xref: /openbmc/linux/net/mac80211/mesh_plink.c (revision 9cdb81c7)
1 /*
2  * Copyright (c) 2008, 2009 open80211s Ltd.
3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  */
9 #include <linux/gfp.h>
10 #include <linux/kernel.h>
11 #include <linux/random.h>
12 #include "ieee80211_i.h"
13 #include "rate.h"
14 #include "mesh.h"
15 
16 #ifdef CONFIG_MAC80211_VERBOSE_MPL_DEBUG
17 #define mpl_dbg(fmt, args...)	printk(KERN_DEBUG fmt, ##args)
18 #else
19 #define mpl_dbg(fmt, args...)	do { (void)(0); } while (0)
20 #endif
21 
22 #define PLINK_GET_LLID(p) (p + 2)
23 #define PLINK_GET_PLID(p) (p + 4)
24 
25 #define mod_plink_timer(s, t) (mod_timer(&s->plink_timer, \
26 				jiffies + HZ * t / 1000))
27 
28 #define dot11MeshMaxRetries(s) (s->u.mesh.mshcfg.dot11MeshMaxRetries)
29 #define dot11MeshRetryTimeout(s) (s->u.mesh.mshcfg.dot11MeshRetryTimeout)
30 #define dot11MeshConfirmTimeout(s) (s->u.mesh.mshcfg.dot11MeshConfirmTimeout)
31 #define dot11MeshHoldingTimeout(s) (s->u.mesh.mshcfg.dot11MeshHoldingTimeout)
32 #define dot11MeshMaxPeerLinks(s) (s->u.mesh.mshcfg.dot11MeshMaxPeerLinks)
33 
34 /* We only need a valid sta if user configured a minimum rssi_threshold. */
35 #define rssi_threshold_check(sta, sdata) \
36 		(sdata->u.mesh.mshcfg.rssi_threshold == 0 ||\
37 		(sta && (s8) -ewma_read(&sta->avg_signal) > \
38 		sdata->u.mesh.mshcfg.rssi_threshold))
39 
40 enum plink_event {
41 	PLINK_UNDEFINED,
42 	OPN_ACPT,
43 	OPN_RJCT,
44 	OPN_IGNR,
45 	CNF_ACPT,
46 	CNF_RJCT,
47 	CNF_IGNR,
48 	CLS_ACPT,
49 	CLS_IGNR
50 };
51 
52 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
53 		enum ieee80211_self_protected_actioncode action,
54 		u8 *da, __le16 llid, __le16 plid, __le16 reason);
55 
56 static inline
57 void mesh_plink_inc_estab_count(struct ieee80211_sub_if_data *sdata)
58 {
59 	atomic_inc(&sdata->u.mesh.mshstats.estab_plinks);
60 	mesh_accept_plinks_update(sdata);
61 }
62 
63 static inline
64 void mesh_plink_dec_estab_count(struct ieee80211_sub_if_data *sdata)
65 {
66 	atomic_dec(&sdata->u.mesh.mshstats.estab_plinks);
67 	mesh_accept_plinks_update(sdata);
68 }
69 
70 /**
71  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
72  *
73  * @sta: mesh peer link to restart
74  *
75  * Locking: this function must be called holding sta->lock
76  */
77 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
78 {
79 	sta->plink_state = NL80211_PLINK_LISTEN;
80 	sta->llid = sta->plid = sta->reason = 0;
81 	sta->plink_retries = 0;
82 }
83 
84 /*
85  * NOTE: This is just an alias for sta_info_alloc(), see notes
86  *       on it in the lifecycle management section!
87  */
88 static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
89 					 u8 *hw_addr, u32 rates,
90 					 struct ieee802_11_elems *elems)
91 {
92 	struct ieee80211_local *local = sdata->local;
93 	struct ieee80211_supported_band *sband;
94 	struct sta_info *sta;
95 
96 	sband = local->hw.wiphy->bands[local->oper_channel->band];
97 
98 	if (local->num_sta >= MESH_MAX_PLINKS)
99 		return NULL;
100 
101 	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
102 	if (!sta)
103 		return NULL;
104 
105 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
106 	sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
107 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
108 
109 	set_sta_flag(sta, WLAN_STA_WME);
110 
111 	sta->sta.supp_rates[local->hw.conf.channel->band] = rates;
112 	if (elems->ht_cap_elem)
113 		ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
114 						  elems->ht_cap_elem,
115 						  &sta->sta.ht_cap);
116 	rate_control_rate_init(sta);
117 
118 	return sta;
119 }
120 
121 /**
122  * __mesh_plink_deactivate - deactivate mesh peer link
123  *
124  * @sta: mesh peer link to deactivate
125  *
126  * All mesh paths with this peer as next hop will be flushed
127  *
128  * Locking: the caller must hold sta->lock
129  */
130 static bool __mesh_plink_deactivate(struct sta_info *sta)
131 {
132 	struct ieee80211_sub_if_data *sdata = sta->sdata;
133 	bool deactivated = false;
134 
135 	if (sta->plink_state == NL80211_PLINK_ESTAB) {
136 		mesh_plink_dec_estab_count(sdata);
137 		deactivated = true;
138 	}
139 	sta->plink_state = NL80211_PLINK_BLOCKED;
140 	mesh_path_flush_by_nexthop(sta);
141 
142 	return deactivated;
143 }
144 
145 /**
146  * mesh_plink_deactivate - deactivate mesh peer link
147  *
148  * @sta: mesh peer link to deactivate
149  *
150  * All mesh paths with this peer as next hop will be flushed
151  */
152 void mesh_plink_deactivate(struct sta_info *sta)
153 {
154 	struct ieee80211_sub_if_data *sdata = sta->sdata;
155 	bool deactivated;
156 
157 	spin_lock_bh(&sta->lock);
158 	deactivated = __mesh_plink_deactivate(sta);
159 	sta->reason = cpu_to_le16(WLAN_REASON_MESH_PEER_CANCELED);
160 	mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
161 			    sta->sta.addr, sta->llid, sta->plid,
162 			    sta->reason);
163 	spin_unlock_bh(&sta->lock);
164 
165 	if (deactivated)
166 		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
167 }
168 
169 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
170 		enum ieee80211_self_protected_actioncode action,
171 		u8 *da, __le16 llid, __le16 plid, __le16 reason) {
172 	struct ieee80211_local *local = sdata->local;
173 	struct sk_buff *skb;
174 	struct ieee80211_mgmt *mgmt;
175 	bool include_plid = false;
176 	u16 peering_proto = 0;
177 	u8 *pos, ie_len = 4;
178 	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
179 		      sizeof(mgmt->u.action.u.self_prot);
180 
181 	skb = dev_alloc_skb(local->tx_headroom +
182 			    hdr_len +
183 			    2 + /* capability info */
184 			    2 + /* AID */
185 			    2 + 8 + /* supported rates */
186 			    2 + (IEEE80211_MAX_SUPP_RATES - 8) +
187 			    2 + sdata->u.mesh.mesh_id_len +
188 			    2 + sizeof(struct ieee80211_meshconf_ie) +
189 			    2 + sizeof(struct ieee80211_ht_cap) +
190 			    2 + sizeof(struct ieee80211_ht_info) +
191 			    2 + 8 + /* peering IE */
192 			    sdata->u.mesh.ie_len);
193 	if (!skb)
194 		return -1;
195 	skb_reserve(skb, local->tx_headroom);
196 	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
197 	memset(mgmt, 0, hdr_len);
198 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
199 					  IEEE80211_STYPE_ACTION);
200 	memcpy(mgmt->da, da, ETH_ALEN);
201 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
202 	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
203 	mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
204 	mgmt->u.action.u.self_prot.action_code = action;
205 
206 	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
207 		/* capability info */
208 		pos = skb_put(skb, 2);
209 		memset(pos, 0, 2);
210 		if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
211 			/* AID */
212 			pos = skb_put(skb, 2);
213 			memcpy(pos + 2, &plid, 2);
214 		}
215 		if (ieee80211_add_srates_ie(&sdata->vif, skb) ||
216 		    ieee80211_add_ext_srates_ie(&sdata->vif, skb) ||
217 		    mesh_add_rsn_ie(skb, sdata) ||
218 		    mesh_add_meshid_ie(skb, sdata) ||
219 		    mesh_add_meshconf_ie(skb, sdata))
220 			return -1;
221 	} else {	/* WLAN_SP_MESH_PEERING_CLOSE */
222 		if (mesh_add_meshid_ie(skb, sdata))
223 			return -1;
224 	}
225 
226 	/* Add Mesh Peering Management element */
227 	switch (action) {
228 	case WLAN_SP_MESH_PEERING_OPEN:
229 		break;
230 	case WLAN_SP_MESH_PEERING_CONFIRM:
231 		ie_len += 2;
232 		include_plid = true;
233 		break;
234 	case WLAN_SP_MESH_PEERING_CLOSE:
235 		if (plid) {
236 			ie_len += 2;
237 			include_plid = true;
238 		}
239 		ie_len += 2;	/* reason code */
240 		break;
241 	default:
242 		return -EINVAL;
243 	}
244 
245 	if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
246 		return -ENOMEM;
247 
248 	pos = skb_put(skb, 2 + ie_len);
249 	*pos++ = WLAN_EID_PEER_MGMT;
250 	*pos++ = ie_len;
251 	memcpy(pos, &peering_proto, 2);
252 	pos += 2;
253 	memcpy(pos, &llid, 2);
254 	pos += 2;
255 	if (include_plid) {
256 		memcpy(pos, &plid, 2);
257 		pos += 2;
258 	}
259 	if (action == WLAN_SP_MESH_PEERING_CLOSE) {
260 		memcpy(pos, &reason, 2);
261 		pos += 2;
262 	}
263 
264 	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
265 		if (mesh_add_ht_cap_ie(skb, sdata) ||
266 		    mesh_add_ht_info_ie(skb, sdata))
267 			return -1;
268 	}
269 
270 	if (mesh_add_vendor_ies(skb, sdata))
271 		return -1;
272 
273 	ieee80211_tx_skb(sdata, skb);
274 	return 0;
275 }
276 
277 void mesh_neighbour_update(u8 *hw_addr, u32 rates,
278 		struct ieee80211_sub_if_data *sdata,
279 		struct ieee802_11_elems *elems)
280 {
281 	struct ieee80211_local *local = sdata->local;
282 	struct sta_info *sta;
283 
284 	rcu_read_lock();
285 
286 	sta = sta_info_get(sdata, hw_addr);
287 	if (!sta) {
288 		rcu_read_unlock();
289 		/* Userspace handles peer allocation when security is enabled
290 		 * */
291 		if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
292 			cfg80211_notify_new_peer_candidate(sdata->dev, hw_addr,
293 					elems->ie_start, elems->total_len,
294 					GFP_KERNEL);
295 		else
296 			sta = mesh_plink_alloc(sdata, hw_addr, rates, elems);
297 		if (!sta)
298 			return;
299 		if (sta_info_insert_rcu(sta)) {
300 			rcu_read_unlock();
301 			return;
302 		}
303 	}
304 
305 	sta->last_rx = jiffies;
306 	sta->sta.supp_rates[local->hw.conf.channel->band] = rates;
307 	if (mesh_peer_accepts_plinks(elems) &&
308 			sta->plink_state == NL80211_PLINK_LISTEN &&
309 			sdata->u.mesh.accepting_plinks &&
310 			sdata->u.mesh.mshcfg.auto_open_plinks &&
311 			rssi_threshold_check(sta, sdata))
312 		mesh_plink_open(sta);
313 
314 	rcu_read_unlock();
315 }
316 
317 static void mesh_plink_timer(unsigned long data)
318 {
319 	struct sta_info *sta;
320 	__le16 llid, plid, reason;
321 	struct ieee80211_sub_if_data *sdata;
322 
323 	/*
324 	 * This STA is valid because sta_info_destroy() will
325 	 * del_timer_sync() this timer after having made sure
326 	 * it cannot be readded (by deleting the plink.)
327 	 */
328 	sta = (struct sta_info *) data;
329 
330 	if (sta->sdata->local->quiescing) {
331 		sta->plink_timer_was_running = true;
332 		return;
333 	}
334 
335 	spin_lock_bh(&sta->lock);
336 	if (sta->ignore_plink_timer) {
337 		sta->ignore_plink_timer = false;
338 		spin_unlock_bh(&sta->lock);
339 		return;
340 	}
341 	mpl_dbg("Mesh plink timer for %pM fired on state %d\n",
342 		sta->sta.addr, sta->plink_state);
343 	reason = 0;
344 	llid = sta->llid;
345 	plid = sta->plid;
346 	sdata = sta->sdata;
347 
348 	switch (sta->plink_state) {
349 	case NL80211_PLINK_OPN_RCVD:
350 	case NL80211_PLINK_OPN_SNT:
351 		/* retry timer */
352 		if (sta->plink_retries < dot11MeshMaxRetries(sdata)) {
353 			u32 rand;
354 			mpl_dbg("Mesh plink for %pM (retry, timeout): %d %d\n",
355 				sta->sta.addr, sta->plink_retries,
356 				sta->plink_timeout);
357 			get_random_bytes(&rand, sizeof(u32));
358 			sta->plink_timeout = sta->plink_timeout +
359 					     rand % sta->plink_timeout;
360 			++sta->plink_retries;
361 			mod_plink_timer(sta, sta->plink_timeout);
362 			spin_unlock_bh(&sta->lock);
363 			mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
364 					    sta->sta.addr, llid, 0, 0);
365 			break;
366 		}
367 		reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);
368 		/* fall through on else */
369 	case NL80211_PLINK_CNF_RCVD:
370 		/* confirm timer */
371 		if (!reason)
372 			reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);
373 		sta->plink_state = NL80211_PLINK_HOLDING;
374 		mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
375 		spin_unlock_bh(&sta->lock);
376 		mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
377 				    sta->sta.addr, llid, plid, reason);
378 		break;
379 	case NL80211_PLINK_HOLDING:
380 		/* holding timer */
381 		del_timer(&sta->plink_timer);
382 		mesh_plink_fsm_restart(sta);
383 		spin_unlock_bh(&sta->lock);
384 		break;
385 	default:
386 		spin_unlock_bh(&sta->lock);
387 		break;
388 	}
389 }
390 
391 #ifdef CONFIG_PM
392 void mesh_plink_quiesce(struct sta_info *sta)
393 {
394 	if (del_timer_sync(&sta->plink_timer))
395 		sta->plink_timer_was_running = true;
396 }
397 
398 void mesh_plink_restart(struct sta_info *sta)
399 {
400 	if (sta->plink_timer_was_running) {
401 		add_timer(&sta->plink_timer);
402 		sta->plink_timer_was_running = false;
403 	}
404 }
405 #endif
406 
407 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
408 {
409 	sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
410 	sta->plink_timer.data = (unsigned long) sta;
411 	sta->plink_timer.function = mesh_plink_timer;
412 	sta->plink_timeout = timeout;
413 	add_timer(&sta->plink_timer);
414 }
415 
416 int mesh_plink_open(struct sta_info *sta)
417 {
418 	__le16 llid;
419 	struct ieee80211_sub_if_data *sdata = sta->sdata;
420 
421 	if (!test_sta_flag(sta, WLAN_STA_AUTH))
422 		return -EPERM;
423 
424 	spin_lock_bh(&sta->lock);
425 	get_random_bytes(&llid, 2);
426 	sta->llid = llid;
427 	if (sta->plink_state != NL80211_PLINK_LISTEN) {
428 		spin_unlock_bh(&sta->lock);
429 		return -EBUSY;
430 	}
431 	sta->plink_state = NL80211_PLINK_OPN_SNT;
432 	mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
433 	spin_unlock_bh(&sta->lock);
434 	mpl_dbg("Mesh plink: starting establishment with %pM\n",
435 		sta->sta.addr);
436 
437 	return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
438 				   sta->sta.addr, llid, 0, 0);
439 }
440 
441 void mesh_plink_block(struct sta_info *sta)
442 {
443 	struct ieee80211_sub_if_data *sdata = sta->sdata;
444 	bool deactivated;
445 
446 	spin_lock_bh(&sta->lock);
447 	deactivated = __mesh_plink_deactivate(sta);
448 	sta->plink_state = NL80211_PLINK_BLOCKED;
449 	spin_unlock_bh(&sta->lock);
450 
451 	if (deactivated)
452 		ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
453 }
454 
455 
456 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,
457 			 size_t len, struct ieee80211_rx_status *rx_status)
458 {
459 	struct ieee80211_local *local = sdata->local;
460 	struct ieee802_11_elems elems;
461 	struct sta_info *sta;
462 	enum plink_event event;
463 	enum ieee80211_self_protected_actioncode ftype;
464 	size_t baselen;
465 	bool deactivated, matches_local = true;
466 	u8 ie_len;
467 	u8 *baseaddr;
468 	__le16 plid, llid, reason;
469 #ifdef CONFIG_MAC80211_VERBOSE_MPL_DEBUG
470 	static const char *mplstates[] = {
471 		[NL80211_PLINK_LISTEN] = "LISTEN",
472 		[NL80211_PLINK_OPN_SNT] = "OPN-SNT",
473 		[NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
474 		[NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
475 		[NL80211_PLINK_ESTAB] = "ESTAB",
476 		[NL80211_PLINK_HOLDING] = "HOLDING",
477 		[NL80211_PLINK_BLOCKED] = "BLOCKED"
478 	};
479 #endif
480 
481 	/* need action_code, aux */
482 	if (len < IEEE80211_MIN_ACTION_SIZE + 3)
483 		return;
484 
485 	if (is_multicast_ether_addr(mgmt->da)) {
486 		mpl_dbg("Mesh plink: ignore frame from multicast address");
487 		return;
488 	}
489 
490 	baseaddr = mgmt->u.action.u.self_prot.variable;
491 	baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
492 	if (mgmt->u.action.u.self_prot.action_code ==
493 						WLAN_SP_MESH_PEERING_CONFIRM) {
494 		baseaddr += 4;
495 		baselen += 4;
496 	}
497 	ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
498 	if (!elems.peering) {
499 		mpl_dbg("Mesh plink: missing necessary peer link ie\n");
500 		return;
501 	}
502 	if (elems.rsn_len &&
503 			sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
504 		mpl_dbg("Mesh plink: can't establish link with secure peer\n");
505 		return;
506 	}
507 
508 	ftype = mgmt->u.action.u.self_prot.action_code;
509 	ie_len = elems.peering_len;
510 	if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
511 	    (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
512 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
513 							&& ie_len != 8)) {
514 		mpl_dbg("Mesh plink: incorrect plink ie length %d %d\n",
515 		    ftype, ie_len);
516 		return;
517 	}
518 
519 	if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
520 				(!elems.mesh_id || !elems.mesh_config)) {
521 		mpl_dbg("Mesh plink: missing necessary ie\n");
522 		return;
523 	}
524 	/* Note the lines below are correct, the llid in the frame is the plid
525 	 * from the point of view of this host.
526 	 */
527 	memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
528 	if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
529 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
530 		memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
531 
532 	rcu_read_lock();
533 
534 	sta = sta_info_get(sdata, mgmt->sa);
535 	if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
536 		mpl_dbg("Mesh plink: cls or cnf from unknown peer\n");
537 		rcu_read_unlock();
538 		return;
539 	}
540 
541 	if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
542 	    !rssi_threshold_check(sta, sdata)) {
543 		mpl_dbg("Mesh plink: %pM does not meet rssi threshold\n",
544 			mgmt->sa);
545 		rcu_read_unlock();
546 		return;
547 	}
548 
549 	if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
550 		mpl_dbg("Mesh plink: Action frame from non-authed peer\n");
551 		rcu_read_unlock();
552 		return;
553 	}
554 
555 	if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
556 		rcu_read_unlock();
557 		return;
558 	}
559 
560 	/* Now we will figure out the appropriate event... */
561 	event = PLINK_UNDEFINED;
562 	if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
563 	    (!mesh_matches_local(&elems, sdata))) {
564 		matches_local = false;
565 		switch (ftype) {
566 		case WLAN_SP_MESH_PEERING_OPEN:
567 			event = OPN_RJCT;
568 			break;
569 		case WLAN_SP_MESH_PEERING_CONFIRM:
570 			event = CNF_RJCT;
571 			break;
572 		default:
573 			break;
574 		}
575 	}
576 
577 	if (!sta && !matches_local) {
578 		rcu_read_unlock();
579 		reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
580 		llid = 0;
581 		mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
582 				    mgmt->sa, llid, plid, reason);
583 		return;
584 	} else if (!sta) {
585 		/* ftype == WLAN_SP_MESH_PEERING_OPEN */
586 		u32 rates;
587 
588 		rcu_read_unlock();
589 
590 		if (!mesh_plink_free_count(sdata)) {
591 			mpl_dbg("Mesh plink error: no more free plinks\n");
592 			return;
593 		}
594 
595 		rates = ieee80211_sta_get_rates(local, &elems, rx_status->band);
596 		sta = mesh_plink_alloc(sdata, mgmt->sa, rates, &elems);
597 		if (!sta) {
598 			mpl_dbg("Mesh plink error: plink table full\n");
599 			return;
600 		}
601 		if (sta_info_insert_rcu(sta)) {
602 			rcu_read_unlock();
603 			return;
604 		}
605 		event = OPN_ACPT;
606 		spin_lock_bh(&sta->lock);
607 	} else if (matches_local) {
608 		spin_lock_bh(&sta->lock);
609 		switch (ftype) {
610 		case WLAN_SP_MESH_PEERING_OPEN:
611 			if (!mesh_plink_free_count(sdata) ||
612 			    (sta->plid && sta->plid != plid))
613 				event = OPN_IGNR;
614 			else
615 				event = OPN_ACPT;
616 			break;
617 		case WLAN_SP_MESH_PEERING_CONFIRM:
618 			if (!mesh_plink_free_count(sdata) ||
619 			    (sta->llid != llid || sta->plid != plid))
620 				event = CNF_IGNR;
621 			else
622 				event = CNF_ACPT;
623 			break;
624 		case WLAN_SP_MESH_PEERING_CLOSE:
625 			if (sta->plink_state == NL80211_PLINK_ESTAB)
626 				/* Do not check for llid or plid. This does not
627 				 * follow the standard but since multiple plinks
628 				 * per sta are not supported, it is necessary in
629 				 * order to avoid a livelock when MP A sees an
630 				 * establish peer link to MP B but MP B does not
631 				 * see it. This can be caused by a timeout in
632 				 * B's peer link establishment or B beign
633 				 * restarted.
634 				 */
635 				event = CLS_ACPT;
636 			else if (sta->plid != plid)
637 				event = CLS_IGNR;
638 			else if (ie_len == 7 && sta->llid != llid)
639 				event = CLS_IGNR;
640 			else
641 				event = CLS_ACPT;
642 			break;
643 		default:
644 			mpl_dbg("Mesh plink: unknown frame subtype\n");
645 			spin_unlock_bh(&sta->lock);
646 			rcu_read_unlock();
647 			return;
648 		}
649 	} else {
650 		spin_lock_bh(&sta->lock);
651 	}
652 
653 	mpl_dbg("Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
654 		mgmt->sa, mplstates[sta->plink_state],
655 		le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
656 		event);
657 	reason = 0;
658 	switch (sta->plink_state) {
659 		/* spin_unlock as soon as state is updated at each case */
660 	case NL80211_PLINK_LISTEN:
661 		switch (event) {
662 		case CLS_ACPT:
663 			mesh_plink_fsm_restart(sta);
664 			spin_unlock_bh(&sta->lock);
665 			break;
666 		case OPN_ACPT:
667 			sta->plink_state = NL80211_PLINK_OPN_RCVD;
668 			sta->plid = plid;
669 			get_random_bytes(&llid, 2);
670 			sta->llid = llid;
671 			mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
672 			spin_unlock_bh(&sta->lock);
673 			mesh_plink_frame_tx(sdata,
674 					    WLAN_SP_MESH_PEERING_OPEN,
675 					    sta->sta.addr, llid, 0, 0);
676 			mesh_plink_frame_tx(sdata,
677 					    WLAN_SP_MESH_PEERING_CONFIRM,
678 					    sta->sta.addr, llid, plid, 0);
679 			break;
680 		default:
681 			spin_unlock_bh(&sta->lock);
682 			break;
683 		}
684 		break;
685 
686 	case NL80211_PLINK_OPN_SNT:
687 		switch (event) {
688 		case OPN_RJCT:
689 		case CNF_RJCT:
690 			reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
691 		case CLS_ACPT:
692 			if (!reason)
693 				reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
694 			sta->reason = reason;
695 			sta->plink_state = NL80211_PLINK_HOLDING;
696 			if (!mod_plink_timer(sta,
697 					     dot11MeshHoldingTimeout(sdata)))
698 				sta->ignore_plink_timer = true;
699 
700 			llid = sta->llid;
701 			spin_unlock_bh(&sta->lock);
702 			mesh_plink_frame_tx(sdata,
703 					    WLAN_SP_MESH_PEERING_CLOSE,
704 					    sta->sta.addr, llid, plid, reason);
705 			break;
706 		case OPN_ACPT:
707 			/* retry timer is left untouched */
708 			sta->plink_state = NL80211_PLINK_OPN_RCVD;
709 			sta->plid = plid;
710 			llid = sta->llid;
711 			spin_unlock_bh(&sta->lock);
712 			mesh_plink_frame_tx(sdata,
713 					    WLAN_SP_MESH_PEERING_CONFIRM,
714 					    sta->sta.addr, llid, plid, 0);
715 			break;
716 		case CNF_ACPT:
717 			sta->plink_state = NL80211_PLINK_CNF_RCVD;
718 			if (!mod_plink_timer(sta,
719 					     dot11MeshConfirmTimeout(sdata)))
720 				sta->ignore_plink_timer = true;
721 
722 			spin_unlock_bh(&sta->lock);
723 			break;
724 		default:
725 			spin_unlock_bh(&sta->lock);
726 			break;
727 		}
728 		break;
729 
730 	case NL80211_PLINK_OPN_RCVD:
731 		switch (event) {
732 		case OPN_RJCT:
733 		case CNF_RJCT:
734 			reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
735 		case CLS_ACPT:
736 			if (!reason)
737 				reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
738 			sta->reason = reason;
739 			sta->plink_state = NL80211_PLINK_HOLDING;
740 			if (!mod_plink_timer(sta,
741 					     dot11MeshHoldingTimeout(sdata)))
742 				sta->ignore_plink_timer = true;
743 
744 			llid = sta->llid;
745 			spin_unlock_bh(&sta->lock);
746 			mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
747 					    sta->sta.addr, llid, plid, reason);
748 			break;
749 		case OPN_ACPT:
750 			llid = sta->llid;
751 			spin_unlock_bh(&sta->lock);
752 			mesh_plink_frame_tx(sdata,
753 					    WLAN_SP_MESH_PEERING_CONFIRM,
754 					    sta->sta.addr, llid, plid, 0);
755 			break;
756 		case CNF_ACPT:
757 			del_timer(&sta->plink_timer);
758 			sta->plink_state = NL80211_PLINK_ESTAB;
759 			spin_unlock_bh(&sta->lock);
760 			mesh_plink_inc_estab_count(sdata);
761 			ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
762 			mpl_dbg("Mesh plink with %pM ESTABLISHED\n",
763 				sta->sta.addr);
764 			break;
765 		default:
766 			spin_unlock_bh(&sta->lock);
767 			break;
768 		}
769 		break;
770 
771 	case NL80211_PLINK_CNF_RCVD:
772 		switch (event) {
773 		case OPN_RJCT:
774 		case CNF_RJCT:
775 			reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
776 		case CLS_ACPT:
777 			if (!reason)
778 				reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
779 			sta->reason = reason;
780 			sta->plink_state = NL80211_PLINK_HOLDING;
781 			if (!mod_plink_timer(sta,
782 					     dot11MeshHoldingTimeout(sdata)))
783 				sta->ignore_plink_timer = true;
784 
785 			llid = sta->llid;
786 			spin_unlock_bh(&sta->lock);
787 			mesh_plink_frame_tx(sdata,
788 					    WLAN_SP_MESH_PEERING_CLOSE,
789 					    sta->sta.addr, llid, plid, reason);
790 			break;
791 		case OPN_ACPT:
792 			del_timer(&sta->plink_timer);
793 			sta->plink_state = NL80211_PLINK_ESTAB;
794 			spin_unlock_bh(&sta->lock);
795 			mesh_plink_inc_estab_count(sdata);
796 			ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
797 			mpl_dbg("Mesh plink with %pM ESTABLISHED\n",
798 				sta->sta.addr);
799 			mesh_plink_frame_tx(sdata,
800 					    WLAN_SP_MESH_PEERING_CONFIRM,
801 					    sta->sta.addr, llid, plid, 0);
802 			break;
803 		default:
804 			spin_unlock_bh(&sta->lock);
805 			break;
806 		}
807 		break;
808 
809 	case NL80211_PLINK_ESTAB:
810 		switch (event) {
811 		case CLS_ACPT:
812 			reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
813 			sta->reason = reason;
814 			deactivated = __mesh_plink_deactivate(sta);
815 			sta->plink_state = NL80211_PLINK_HOLDING;
816 			llid = sta->llid;
817 			mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
818 			spin_unlock_bh(&sta->lock);
819 			if (deactivated)
820 				ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
821 			mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
822 					    sta->sta.addr, llid, plid, reason);
823 			break;
824 		case OPN_ACPT:
825 			llid = sta->llid;
826 			spin_unlock_bh(&sta->lock);
827 			mesh_plink_frame_tx(sdata,
828 					    WLAN_SP_MESH_PEERING_CONFIRM,
829 					    sta->sta.addr, llid, plid, 0);
830 			break;
831 		default:
832 			spin_unlock_bh(&sta->lock);
833 			break;
834 		}
835 		break;
836 	case NL80211_PLINK_HOLDING:
837 		switch (event) {
838 		case CLS_ACPT:
839 			if (del_timer(&sta->plink_timer))
840 				sta->ignore_plink_timer = 1;
841 			mesh_plink_fsm_restart(sta);
842 			spin_unlock_bh(&sta->lock);
843 			break;
844 		case OPN_ACPT:
845 		case CNF_ACPT:
846 		case OPN_RJCT:
847 		case CNF_RJCT:
848 			llid = sta->llid;
849 			reason = sta->reason;
850 			spin_unlock_bh(&sta->lock);
851 			mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
852 					    sta->sta.addr, llid, plid, reason);
853 			break;
854 		default:
855 			spin_unlock_bh(&sta->lock);
856 		}
857 		break;
858 	default:
859 		/* should not get here, PLINK_BLOCKED is dealt with at the
860 		 * beginning of the function
861 		 */
862 		spin_unlock_bh(&sta->lock);
863 		break;
864 	}
865 
866 	rcu_read_unlock();
867 }
868