xref: /linux/net/mac80211/mesh_plink.c (revision 8b8eed05a1c650c27e78bc47d07f7d6c9ba779e8)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2008, 2009 open80211s Ltd.
4  * Copyright (C) 2019, 2021-2023 Intel Corporation
5  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
6  */
7 #include <linux/gfp.h>
8 #include <linux/kernel.h>
9 #include <linux/random.h>
10 #include <linux/rculist.h>
11 
12 #include "ieee80211_i.h"
13 #include "rate.h"
14 #include "mesh.h"
15 
16 #define PLINK_CNF_AID(mgmt) ((mgmt)->u.action.u.self_prot.variable + 2)
17 #define PLINK_GET_LLID(p) (p + 2)
18 #define PLINK_GET_PLID(p) (p + 4)
19 
20 #define mod_plink_timer(s, t) (mod_timer(&s->mesh->plink_timer, \
21 				jiffies + msecs_to_jiffies(t)))
22 
23 enum plink_event {
24 	PLINK_UNDEFINED,
25 	OPN_ACPT,
26 	OPN_RJCT,
27 	OPN_IGNR,
28 	CNF_ACPT,
29 	CNF_RJCT,
30 	CNF_IGNR,
31 	CLS_ACPT,
32 	CLS_IGNR
33 };
34 
35 static const char * const mplstates[] = {
36 	[NL80211_PLINK_LISTEN] = "LISTEN",
37 	[NL80211_PLINK_OPN_SNT] = "OPN-SNT",
38 	[NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
39 	[NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
40 	[NL80211_PLINK_ESTAB] = "ESTAB",
41 	[NL80211_PLINK_HOLDING] = "HOLDING",
42 	[NL80211_PLINK_BLOCKED] = "BLOCKED"
43 };
44 
45 static const char * const mplevents[] = {
46 	[PLINK_UNDEFINED] = "NONE",
47 	[OPN_ACPT] = "OPN_ACPT",
48 	[OPN_RJCT] = "OPN_RJCT",
49 	[OPN_IGNR] = "OPN_IGNR",
50 	[CNF_ACPT] = "CNF_ACPT",
51 	[CNF_RJCT] = "CNF_RJCT",
52 	[CNF_IGNR] = "CNF_IGNR",
53 	[CLS_ACPT] = "CLS_ACPT",
54 	[CLS_IGNR] = "CLS_IGNR"
55 };
56 
57 /* We only need a valid sta if user configured a minimum rssi_threshold. */
58 static bool rssi_threshold_check(struct ieee80211_sub_if_data *sdata,
59 				 struct sta_info *sta)
60 {
61 	s32 rssi_threshold = sdata->u.mesh.mshcfg.rssi_threshold;
62 	return rssi_threshold == 0 ||
63 	       (sta &&
64 		(s8)-ewma_signal_read(&sta->deflink.rx_stats_avg.signal) >
65 		rssi_threshold);
66 }
67 
68 /**
69  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
70  *
71  * @sta: mesh peer link to restart
72  *
73  * Locking: this function must be called holding sta->mesh->plink_lock
74  */
75 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
76 {
77 	lockdep_assert_held(&sta->mesh->plink_lock);
78 	sta->mesh->plink_state = NL80211_PLINK_LISTEN;
79 	sta->mesh->llid = sta->mesh->plid = sta->mesh->reason = 0;
80 	sta->mesh->plink_retries = 0;
81 }
82 
83 /*
84  * mesh_set_short_slot_time - enable / disable ERP short slot time.
85  *
86  * The standard indirectly mandates mesh STAs to turn off short slot time by
87  * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
88  * can't be sneaky about it. Enable short slot time if all mesh STAs in the
89  * MBSS support ERP rates.
90  *
91  * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
92  */
93 static u64 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
94 {
95 	struct ieee80211_local *local = sdata->local;
96 	struct ieee80211_supported_band *sband;
97 	struct sta_info *sta;
98 	u32 erp_rates = 0;
99 	u64 changed = 0;
100 	int i;
101 	bool short_slot = false;
102 
103 	sband = ieee80211_get_sband(sdata);
104 	if (!sband)
105 		return changed;
106 
107 	if (sband->band == NL80211_BAND_5GHZ) {
108 		/* (IEEE 802.11-2012 19.4.5) */
109 		short_slot = true;
110 		goto out;
111 	} else if (sband->band != NL80211_BAND_2GHZ) {
112 		goto out;
113 	}
114 
115 	for (i = 0; i < sband->n_bitrates; i++)
116 		if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
117 			erp_rates |= BIT(i);
118 
119 	if (!erp_rates)
120 		goto out;
121 
122 	rcu_read_lock();
123 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
124 		if (sdata != sta->sdata ||
125 		    sta->mesh->plink_state != NL80211_PLINK_ESTAB)
126 			continue;
127 
128 		short_slot = false;
129 		if (erp_rates & sta->sta.deflink.supp_rates[sband->band])
130 			short_slot = true;
131 		 else
132 			break;
133 	}
134 	rcu_read_unlock();
135 
136 out:
137 	if (sdata->vif.bss_conf.use_short_slot != short_slot) {
138 		sdata->vif.bss_conf.use_short_slot = short_slot;
139 		changed = BSS_CHANGED_ERP_SLOT;
140 		mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
141 			sdata->vif.addr, short_slot);
142 	}
143 	return changed;
144 }
145 
146 /**
147  * mesh_set_ht_prot_mode - set correct HT protection mode
148  * @sdata: the (mesh) interface to handle
149  *
150  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
151  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
152  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
153  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
154  * is selected if all peers in our 20/40MHz MBSS support HT and at least one
155  * HT20 peer is present. Otherwise no-protection mode is selected.
156  *
157  * Returns: BSS_CHANGED_HT or 0 for no change
158  */
159 static u64 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
160 {
161 	struct ieee80211_local *local = sdata->local;
162 	struct sta_info *sta;
163 	u16 ht_opmode;
164 	bool non_ht_sta = false, ht20_sta = false;
165 
166 	switch (sdata->vif.bss_conf.chandef.width) {
167 	case NL80211_CHAN_WIDTH_20_NOHT:
168 	case NL80211_CHAN_WIDTH_5:
169 	case NL80211_CHAN_WIDTH_10:
170 		return 0;
171 	default:
172 		break;
173 	}
174 
175 	rcu_read_lock();
176 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
177 		if (sdata != sta->sdata ||
178 		    sta->mesh->plink_state != NL80211_PLINK_ESTAB)
179 			continue;
180 
181 		if (sta->sta.deflink.bandwidth > IEEE80211_STA_RX_BW_20)
182 			continue;
183 
184 		if (!sta->sta.deflink.ht_cap.ht_supported) {
185 			mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
186 				       sta->sta.addr);
187 			non_ht_sta = true;
188 			break;
189 		}
190 
191 		mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
192 		ht20_sta = true;
193 	}
194 	rcu_read_unlock();
195 
196 	if (non_ht_sta)
197 		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
198 	else if (ht20_sta &&
199 		 sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
200 		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
201 	else
202 		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
203 
204 	if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
205 		return 0;
206 
207 	sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
208 	sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
209 	mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
210 	return BSS_CHANGED_HT;
211 }
212 
213 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
214 			       struct sta_info *sta,
215 			       enum ieee80211_self_protected_actioncode action,
216 			       u8 *da, u16 llid, u16 plid, u16 reason)
217 {
218 	struct ieee80211_local *local = sdata->local;
219 	struct sk_buff *skb;
220 	struct ieee80211_tx_info *info;
221 	struct ieee80211_mgmt *mgmt;
222 	bool include_plid = false;
223 	u16 peering_proto = 0;
224 	u8 *pos, ie_len = 4;
225 	u8 ie_len_he_cap, ie_len_eht_cap;
226 	int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.self_prot);
227 	int err = -ENOMEM;
228 
229 	ie_len_he_cap = ieee80211_ie_len_he_cap(sdata,
230 						NL80211_IFTYPE_MESH_POINT);
231 	ie_len_eht_cap = ieee80211_ie_len_eht_cap(sdata,
232 						  NL80211_IFTYPE_MESH_POINT);
233 	skb = dev_alloc_skb(local->tx_headroom +
234 			    hdr_len +
235 			    2 + /* capability info */
236 			    2 + /* AID */
237 			    2 + 8 + /* supported rates */
238 			    2 + (IEEE80211_MAX_SUPP_RATES - 8) +
239 			    2 + sdata->u.mesh.mesh_id_len +
240 			    2 + sizeof(struct ieee80211_meshconf_ie) +
241 			    2 + sizeof(struct ieee80211_ht_cap) +
242 			    2 + sizeof(struct ieee80211_ht_operation) +
243 			    2 + sizeof(struct ieee80211_vht_cap) +
244 			    2 + sizeof(struct ieee80211_vht_operation) +
245 			    ie_len_he_cap +
246 			    2 + 1 + sizeof(struct ieee80211_he_operation) +
247 				    sizeof(struct ieee80211_he_6ghz_oper) +
248 			    2 + 1 + sizeof(struct ieee80211_he_6ghz_capa) +
249 			    ie_len_eht_cap +
250 			    2 + 1 + offsetof(struct ieee80211_eht_operation, optional) +
251 				    offsetof(struct ieee80211_eht_operation_info, optional) +
252 			    2 + 8 + /* peering IE */
253 			    sdata->u.mesh.ie_len);
254 	if (!skb)
255 		return err;
256 	info = IEEE80211_SKB_CB(skb);
257 	skb_reserve(skb, local->tx_headroom);
258 	mgmt = skb_put_zero(skb, hdr_len);
259 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
260 					  IEEE80211_STYPE_ACTION);
261 	memcpy(mgmt->da, da, ETH_ALEN);
262 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
263 	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
264 	mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
265 	mgmt->u.action.u.self_prot.action_code = action;
266 
267 	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
268 		struct ieee80211_supported_band *sband;
269 		enum nl80211_band band;
270 
271 		sband = ieee80211_get_sband(sdata);
272 		if (!sband) {
273 			err = -EINVAL;
274 			goto free;
275 		}
276 		band = sband->band;
277 
278 		/* capability info */
279 		pos = skb_put_zero(skb, 2);
280 		if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
281 			/* AID */
282 			pos = skb_put(skb, 2);
283 			put_unaligned_le16(sta->sta.aid, pos);
284 		}
285 		if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
286 		    ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
287 		    mesh_add_rsn_ie(sdata, skb) ||
288 		    mesh_add_meshid_ie(sdata, skb) ||
289 		    mesh_add_meshconf_ie(sdata, skb))
290 			goto free;
291 	} else {	/* WLAN_SP_MESH_PEERING_CLOSE */
292 		info->flags |= IEEE80211_TX_CTL_NO_ACK;
293 		if (mesh_add_meshid_ie(sdata, skb))
294 			goto free;
295 	}
296 
297 	/* Add Mesh Peering Management element */
298 	switch (action) {
299 	case WLAN_SP_MESH_PEERING_OPEN:
300 		break;
301 	case WLAN_SP_MESH_PEERING_CONFIRM:
302 		ie_len += 2;
303 		include_plid = true;
304 		break;
305 	case WLAN_SP_MESH_PEERING_CLOSE:
306 		if (plid) {
307 			ie_len += 2;
308 			include_plid = true;
309 		}
310 		ie_len += 2;	/* reason code */
311 		break;
312 	default:
313 		err = -EINVAL;
314 		goto free;
315 	}
316 
317 	if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
318 		goto free;
319 
320 	pos = skb_put(skb, 2 + ie_len);
321 	*pos++ = WLAN_EID_PEER_MGMT;
322 	*pos++ = ie_len;
323 	memcpy(pos, &peering_proto, 2);
324 	pos += 2;
325 	put_unaligned_le16(llid, pos);
326 	pos += 2;
327 	if (include_plid) {
328 		put_unaligned_le16(plid, pos);
329 		pos += 2;
330 	}
331 	if (action == WLAN_SP_MESH_PEERING_CLOSE) {
332 		put_unaligned_le16(reason, pos);
333 		pos += 2;
334 	}
335 
336 	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
337 		if (mesh_add_ht_cap_ie(sdata, skb) ||
338 		    mesh_add_ht_oper_ie(sdata, skb) ||
339 		    mesh_add_vht_cap_ie(sdata, skb) ||
340 		    mesh_add_vht_oper_ie(sdata, skb) ||
341 		    mesh_add_he_cap_ie(sdata, skb, ie_len_he_cap) ||
342 		    mesh_add_he_oper_ie(sdata, skb) ||
343 		    mesh_add_he_6ghz_cap_ie(sdata, skb) ||
344 		    mesh_add_eht_cap_ie(sdata, skb, ie_len_eht_cap) ||
345 		    mesh_add_eht_oper_ie(sdata, skb))
346 			goto free;
347 	}
348 
349 	if (mesh_add_vendor_ies(sdata, skb))
350 		goto free;
351 
352 	ieee80211_tx_skb(sdata, skb);
353 	return 0;
354 free:
355 	kfree_skb(skb);
356 	return err;
357 }
358 
359 /**
360  * __mesh_plink_deactivate - deactivate mesh peer link
361  *
362  * @sta: mesh peer link to deactivate
363  *
364  * Mesh paths with this peer as next hop should be flushed
365  * by the caller outside of plink_lock.
366  *
367  * Returns: beacon changed flag if the beacon content changed.
368  *
369  * Locking: the caller must hold sta->mesh->plink_lock
370  */
371 static u64 __mesh_plink_deactivate(struct sta_info *sta)
372 {
373 	struct ieee80211_sub_if_data *sdata = sta->sdata;
374 	u64 changed = 0;
375 
376 	lockdep_assert_held(&sta->mesh->plink_lock);
377 
378 	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
379 		changed = mesh_plink_dec_estab_count(sdata);
380 	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
381 
382 	ieee80211_mps_sta_status_update(sta);
383 	changed |= ieee80211_mps_set_sta_local_pm(sta,
384 			NL80211_MESH_POWER_UNKNOWN);
385 
386 	return changed;
387 }
388 
389 /**
390  * mesh_plink_deactivate - deactivate mesh peer link
391  *
392  * @sta: mesh peer link to deactivate
393  *
394  * All mesh paths with this peer as next hop will be flushed
395  *
396  * Returns: beacon changed flag if the beacon content changed.
397  */
398 u64 mesh_plink_deactivate(struct sta_info *sta)
399 {
400 	struct ieee80211_sub_if_data *sdata = sta->sdata;
401 	u64 changed;
402 
403 	spin_lock_bh(&sta->mesh->plink_lock);
404 	changed = __mesh_plink_deactivate(sta);
405 
406 	if (!sdata->u.mesh.user_mpm) {
407 		sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
408 		mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
409 				    sta->sta.addr, sta->mesh->llid,
410 				    sta->mesh->plid, sta->mesh->reason);
411 	}
412 	spin_unlock_bh(&sta->mesh->plink_lock);
413 	if (!sdata->u.mesh.user_mpm)
414 		del_timer_sync(&sta->mesh->plink_timer);
415 	mesh_path_flush_by_nexthop(sta);
416 
417 	/* make sure no readers can access nexthop sta from here on */
418 	synchronize_net();
419 
420 	return changed;
421 }
422 
423 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
424 			       struct sta_info *sta,
425 			       struct ieee802_11_elems *elems)
426 {
427 	struct ieee80211_local *local = sdata->local;
428 	struct ieee80211_supported_band *sband;
429 	u32 rates, basic_rates = 0, changed = 0;
430 	enum ieee80211_sta_rx_bandwidth bw = sta->sta.deflink.bandwidth;
431 
432 	sband = ieee80211_get_sband(sdata);
433 	if (!sband)
434 		return;
435 
436 	rates = ieee80211_sta_get_rates(sdata, elems, sband->band,
437 					&basic_rates);
438 
439 	spin_lock_bh(&sta->mesh->plink_lock);
440 	sta->deflink.rx_stats.last_rx = jiffies;
441 
442 	/* rates and capabilities don't change during peering */
443 	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
444 	    sta->mesh->processed_beacon)
445 		goto out;
446 	sta->mesh->processed_beacon = true;
447 
448 	if (sta->sta.deflink.supp_rates[sband->band] != rates)
449 		changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
450 	sta->sta.deflink.supp_rates[sband->band] = rates;
451 
452 	if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
453 					      elems->ht_cap_elem,
454 					      &sta->deflink))
455 		changed |= IEEE80211_RC_BW_CHANGED;
456 
457 	ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
458 					    elems->vht_cap_elem, NULL,
459 					    &sta->deflink);
460 
461 	ieee80211_he_cap_ie_to_sta_he_cap(sdata, sband, elems->he_cap,
462 					  elems->he_cap_len,
463 					  elems->he_6ghz_capa,
464 					  &sta->deflink);
465 
466 	ieee80211_eht_cap_ie_to_sta_eht_cap(sdata, sband, elems->he_cap,
467 					    elems->he_cap_len,
468 					    elems->eht_cap, elems->eht_cap_len,
469 					    &sta->deflink);
470 
471 	if (bw != sta->sta.deflink.bandwidth)
472 		changed |= IEEE80211_RC_BW_CHANGED;
473 
474 	/* HT peer is operating 20MHz-only */
475 	if (elems->ht_operation &&
476 	    !(elems->ht_operation->ht_param &
477 	      IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
478 		if (sta->sta.deflink.bandwidth != IEEE80211_STA_RX_BW_20)
479 			changed |= IEEE80211_RC_BW_CHANGED;
480 		sta->sta.deflink.bandwidth = IEEE80211_STA_RX_BW_20;
481 	}
482 
483 	if (!test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
484 		rate_control_rate_init(sta);
485 	else
486 		rate_control_rate_update(local, sband, sta, 0, changed);
487 out:
488 	spin_unlock_bh(&sta->mesh->plink_lock);
489 }
490 
491 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
492 {
493 	struct sta_info *sta;
494 	unsigned long *aid_map;
495 	int aid;
496 
497 	aid_map = bitmap_zalloc(IEEE80211_MAX_AID + 1, GFP_KERNEL);
498 	if (!aid_map)
499 		return -ENOMEM;
500 
501 	/* reserve aid 0 for mcast indication */
502 	__set_bit(0, aid_map);
503 
504 	rcu_read_lock();
505 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
506 		__set_bit(sta->sta.aid, aid_map);
507 	rcu_read_unlock();
508 
509 	aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
510 	bitmap_free(aid_map);
511 
512 	if (aid > IEEE80211_MAX_AID)
513 		return -ENOBUFS;
514 
515 	return aid;
516 }
517 
518 static struct sta_info *
519 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
520 {
521 	struct sta_info *sta;
522 	int aid;
523 
524 	if (sdata->local->num_sta >= MESH_MAX_PLINKS)
525 		return NULL;
526 
527 	aid = mesh_allocate_aid(sdata);
528 	if (aid < 0)
529 		return NULL;
530 
531 	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
532 	if (!sta)
533 		return NULL;
534 
535 	sta->mesh->plink_state = NL80211_PLINK_LISTEN;
536 	sta->sta.wme = true;
537 	sta->sta.aid = aid;
538 
539 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
540 	sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
541 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
542 
543 	return sta;
544 }
545 
546 static struct sta_info *
547 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
548 		    struct ieee802_11_elems *elems,
549 		    struct ieee80211_rx_status *rx_status)
550 {
551 	struct sta_info *sta = NULL;
552 
553 	/* Userspace handles station allocation */
554 	if (sdata->u.mesh.user_mpm ||
555 	    sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
556 		if (mesh_peer_accepts_plinks(elems) &&
557 		    mesh_plink_availables(sdata)) {
558 			int sig = 0;
559 
560 			if (ieee80211_hw_check(&sdata->local->hw, SIGNAL_DBM))
561 				sig = rx_status->signal;
562 
563 			cfg80211_notify_new_peer_candidate(sdata->dev, addr,
564 							   elems->ie_start,
565 							   elems->total_len,
566 							   sig, GFP_KERNEL);
567 		}
568 	} else
569 		sta = __mesh_sta_info_alloc(sdata, addr);
570 
571 	return sta;
572 }
573 
574 /*
575  * mesh_sta_info_get - return mesh sta info entry for @addr.
576  *
577  * @sdata: local meshif
578  * @addr: peer's address
579  * @elems: IEs from beacon or mesh peering frame.
580  * @rx_status: rx status for the frame for signal reporting
581  *
582  * Return existing or newly allocated sta_info under RCU read lock.
583  * (re)initialize with given IEs.
584  */
585 static struct sta_info *
586 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
587 		  u8 *addr, struct ieee802_11_elems *elems,
588 		  struct ieee80211_rx_status *rx_status) __acquires(RCU)
589 {
590 	struct sta_info *sta = NULL;
591 
592 	rcu_read_lock();
593 	sta = sta_info_get(sdata, addr);
594 	if (sta) {
595 		mesh_sta_info_init(sdata, sta, elems);
596 	} else {
597 		rcu_read_unlock();
598 		/* can't run atomic */
599 		sta = mesh_sta_info_alloc(sdata, addr, elems, rx_status);
600 		if (!sta) {
601 			rcu_read_lock();
602 			return NULL;
603 		}
604 
605 		mesh_sta_info_init(sdata, sta, elems);
606 
607 		if (sta_info_insert_rcu(sta))
608 			return NULL;
609 	}
610 
611 	return sta;
612 }
613 
614 /*
615  * mesh_neighbour_update - update or initialize new mesh neighbor.
616  *
617  * @sdata: local meshif
618  * @addr: peer's address
619  * @elems: IEs from beacon or mesh peering frame
620  * @rx_status: rx status for the frame for signal reporting
621  *
622  * Initiates peering if appropriate.
623  */
624 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
625 			   u8 *hw_addr,
626 			   struct ieee802_11_elems *elems,
627 			   struct ieee80211_rx_status *rx_status)
628 {
629 	struct sta_info *sta;
630 	u64 changed = 0;
631 
632 	sta = mesh_sta_info_get(sdata, hw_addr, elems, rx_status);
633 	if (!sta)
634 		goto out;
635 
636 	sta->mesh->connected_to_gate = elems->mesh_config->meshconf_form &
637 		IEEE80211_MESHCONF_FORM_CONNECTED_TO_GATE;
638 
639 	if (mesh_peer_accepts_plinks(elems) &&
640 	    sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
641 	    sdata->u.mesh.accepting_plinks &&
642 	    sdata->u.mesh.mshcfg.auto_open_plinks &&
643 	    rssi_threshold_check(sdata, sta))
644 		changed = mesh_plink_open(sta);
645 
646 	ieee80211_mps_frame_release(sta, elems);
647 out:
648 	rcu_read_unlock();
649 	ieee80211_mbss_info_change_notify(sdata, changed);
650 }
651 
652 void mesh_plink_timer(struct timer_list *t)
653 {
654 	struct mesh_sta *mesh = from_timer(mesh, t, plink_timer);
655 	struct sta_info *sta;
656 	u16 reason = 0;
657 	struct ieee80211_sub_if_data *sdata;
658 	struct mesh_config *mshcfg;
659 	enum ieee80211_self_protected_actioncode action = 0;
660 
661 	/*
662 	 * This STA is valid because sta_info_destroy() will
663 	 * del_timer_sync() this timer after having made sure
664 	 * it cannot be readded (by deleting the plink.)
665 	 */
666 	sta = mesh->plink_sta;
667 
668 	if (sta->sdata->local->quiescing)
669 		return;
670 
671 	spin_lock_bh(&sta->mesh->plink_lock);
672 
673 	/* If a timer fires just before a state transition on another CPU,
674 	 * we may have already extended the timeout and changed state by the
675 	 * time we've acquired the lock and arrived  here.  In that case,
676 	 * skip this timer and wait for the new one.
677 	 */
678 	if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
679 		mpl_dbg(sta->sdata,
680 			"Ignoring timer for %pM in state %s (timer adjusted)",
681 			sta->sta.addr, mplstates[sta->mesh->plink_state]);
682 		spin_unlock_bh(&sta->mesh->plink_lock);
683 		return;
684 	}
685 
686 	/* del_timer() and handler may race when entering these states */
687 	if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
688 	    sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
689 		mpl_dbg(sta->sdata,
690 			"Ignoring timer for %pM in state %s (timer deleted)",
691 			sta->sta.addr, mplstates[sta->mesh->plink_state]);
692 		spin_unlock_bh(&sta->mesh->plink_lock);
693 		return;
694 	}
695 
696 	mpl_dbg(sta->sdata,
697 		"Mesh plink timer for %pM fired on state %s\n",
698 		sta->sta.addr, mplstates[sta->mesh->plink_state]);
699 	sdata = sta->sdata;
700 	mshcfg = &sdata->u.mesh.mshcfg;
701 
702 	switch (sta->mesh->plink_state) {
703 	case NL80211_PLINK_OPN_RCVD:
704 	case NL80211_PLINK_OPN_SNT:
705 		/* retry timer */
706 		if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
707 			u32 rand;
708 			mpl_dbg(sta->sdata,
709 				"Mesh plink for %pM (retry, timeout): %d %d\n",
710 				sta->sta.addr, sta->mesh->plink_retries,
711 				sta->mesh->plink_timeout);
712 			get_random_bytes(&rand, sizeof(u32));
713 			sta->mesh->plink_timeout = sta->mesh->plink_timeout +
714 					     rand % sta->mesh->plink_timeout;
715 			++sta->mesh->plink_retries;
716 			mod_plink_timer(sta, sta->mesh->plink_timeout);
717 			action = WLAN_SP_MESH_PEERING_OPEN;
718 			break;
719 		}
720 		reason = WLAN_REASON_MESH_MAX_RETRIES;
721 		fallthrough;
722 	case NL80211_PLINK_CNF_RCVD:
723 		/* confirm timer */
724 		if (!reason)
725 			reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
726 		sta->mesh->plink_state = NL80211_PLINK_HOLDING;
727 		mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
728 		action = WLAN_SP_MESH_PEERING_CLOSE;
729 		break;
730 	case NL80211_PLINK_HOLDING:
731 		/* holding timer */
732 		del_timer(&sta->mesh->plink_timer);
733 		mesh_plink_fsm_restart(sta);
734 		break;
735 	default:
736 		break;
737 	}
738 	spin_unlock_bh(&sta->mesh->plink_lock);
739 	if (action)
740 		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
741 				    sta->mesh->llid, sta->mesh->plid, reason);
742 }
743 
744 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
745 {
746 	sta->mesh->plink_timeout = timeout;
747 	mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
748 }
749 
750 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
751 			u16 llid)
752 {
753 	struct ieee80211_local *local = sdata->local;
754 	bool in_use = false;
755 	struct sta_info *sta;
756 
757 	rcu_read_lock();
758 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
759 		if (sdata != sta->sdata)
760 			continue;
761 
762 		if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
763 			in_use = true;
764 			break;
765 		}
766 	}
767 	rcu_read_unlock();
768 
769 	return in_use;
770 }
771 
772 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
773 {
774 	u16 llid;
775 
776 	do {
777 		get_random_bytes(&llid, sizeof(llid));
778 	} while (llid_in_use(sdata, llid));
779 
780 	return llid;
781 }
782 
783 u64 mesh_plink_open(struct sta_info *sta)
784 {
785 	struct ieee80211_sub_if_data *sdata = sta->sdata;
786 	u64 changed;
787 
788 	if (!test_sta_flag(sta, WLAN_STA_AUTH))
789 		return 0;
790 
791 	spin_lock_bh(&sta->mesh->plink_lock);
792 	sta->mesh->llid = mesh_get_new_llid(sdata);
793 	if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
794 	    sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
795 		spin_unlock_bh(&sta->mesh->plink_lock);
796 		return 0;
797 	}
798 	sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
799 	mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
800 	spin_unlock_bh(&sta->mesh->plink_lock);
801 	mpl_dbg(sdata,
802 		"Mesh plink: starting establishment with %pM\n",
803 		sta->sta.addr);
804 
805 	/* set the non-peer mode to active during peering */
806 	changed = ieee80211_mps_local_status_update(sdata);
807 
808 	mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
809 			    sta->sta.addr, sta->mesh->llid, 0, 0);
810 	return changed;
811 }
812 
813 u64 mesh_plink_block(struct sta_info *sta)
814 {
815 	u64 changed;
816 
817 	spin_lock_bh(&sta->mesh->plink_lock);
818 	changed = __mesh_plink_deactivate(sta);
819 	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
820 	spin_unlock_bh(&sta->mesh->plink_lock);
821 	mesh_path_flush_by_nexthop(sta);
822 
823 	return changed;
824 }
825 
826 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
827 			     struct sta_info *sta,
828 			     enum plink_event event)
829 {
830 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
831 	u16 reason = (event == CLS_ACPT) ?
832 		     WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
833 
834 	sta->mesh->reason = reason;
835 	sta->mesh->plink_state = NL80211_PLINK_HOLDING;
836 	mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
837 }
838 
839 static u64 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
840 				struct sta_info *sta)
841 {
842 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
843 	u64 changed = 0;
844 
845 	del_timer(&sta->mesh->plink_timer);
846 	sta->mesh->plink_state = NL80211_PLINK_ESTAB;
847 	changed |= mesh_plink_inc_estab_count(sdata);
848 	changed |= mesh_set_ht_prot_mode(sdata);
849 	changed |= mesh_set_short_slot_time(sdata);
850 	mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
851 	ieee80211_mps_sta_status_update(sta);
852 	changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
853 	return changed;
854 }
855 
856 /**
857  * mesh_plink_fsm - step @sta MPM based on @event
858  *
859  * @sdata: interface
860  * @sta: mesh neighbor
861  * @event: peering event
862  *
863  * Return: changed MBSS flags
864  */
865 static u64 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
866 			  struct sta_info *sta, enum plink_event event)
867 {
868 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
869 	enum ieee80211_self_protected_actioncode action = 0;
870 	u64 changed = 0;
871 	bool flush = false;
872 
873 	mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
874 		mplstates[sta->mesh->plink_state], mplevents[event]);
875 
876 	spin_lock_bh(&sta->mesh->plink_lock);
877 	switch (sta->mesh->plink_state) {
878 	case NL80211_PLINK_LISTEN:
879 		switch (event) {
880 		case CLS_ACPT:
881 			mesh_plink_fsm_restart(sta);
882 			break;
883 		case OPN_ACPT:
884 			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
885 			sta->mesh->llid = mesh_get_new_llid(sdata);
886 			mesh_plink_timer_set(sta,
887 					     mshcfg->dot11MeshRetryTimeout);
888 
889 			/* set the non-peer mode to active during peering */
890 			changed |= ieee80211_mps_local_status_update(sdata);
891 			action = WLAN_SP_MESH_PEERING_OPEN;
892 			break;
893 		default:
894 			break;
895 		}
896 		break;
897 	case NL80211_PLINK_OPN_SNT:
898 		switch (event) {
899 		case OPN_RJCT:
900 		case CNF_RJCT:
901 		case CLS_ACPT:
902 			mesh_plink_close(sdata, sta, event);
903 			action = WLAN_SP_MESH_PEERING_CLOSE;
904 			break;
905 		case OPN_ACPT:
906 			/* retry timer is left untouched */
907 			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
908 			action = WLAN_SP_MESH_PEERING_CONFIRM;
909 			break;
910 		case CNF_ACPT:
911 			sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
912 			mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
913 			break;
914 		default:
915 			break;
916 		}
917 		break;
918 	case NL80211_PLINK_OPN_RCVD:
919 		switch (event) {
920 		case OPN_RJCT:
921 		case CNF_RJCT:
922 		case CLS_ACPT:
923 			mesh_plink_close(sdata, sta, event);
924 			action = WLAN_SP_MESH_PEERING_CLOSE;
925 			break;
926 		case OPN_ACPT:
927 			action = WLAN_SP_MESH_PEERING_CONFIRM;
928 			break;
929 		case CNF_ACPT:
930 			changed |= mesh_plink_establish(sdata, sta);
931 			break;
932 		default:
933 			break;
934 		}
935 		break;
936 	case NL80211_PLINK_CNF_RCVD:
937 		switch (event) {
938 		case OPN_RJCT:
939 		case CNF_RJCT:
940 		case CLS_ACPT:
941 			mesh_plink_close(sdata, sta, event);
942 			action = WLAN_SP_MESH_PEERING_CLOSE;
943 			break;
944 		case OPN_ACPT:
945 			changed |= mesh_plink_establish(sdata, sta);
946 			action = WLAN_SP_MESH_PEERING_CONFIRM;
947 			break;
948 		default:
949 			break;
950 		}
951 		break;
952 	case NL80211_PLINK_ESTAB:
953 		switch (event) {
954 		case CLS_ACPT:
955 			changed |= __mesh_plink_deactivate(sta);
956 			changed |= mesh_set_ht_prot_mode(sdata);
957 			changed |= mesh_set_short_slot_time(sdata);
958 			mesh_plink_close(sdata, sta, event);
959 			action = WLAN_SP_MESH_PEERING_CLOSE;
960 			flush = true;
961 			break;
962 		case OPN_ACPT:
963 			action = WLAN_SP_MESH_PEERING_CONFIRM;
964 			break;
965 		default:
966 			break;
967 		}
968 		break;
969 	case NL80211_PLINK_HOLDING:
970 		switch (event) {
971 		case CLS_ACPT:
972 			del_timer(&sta->mesh->plink_timer);
973 			mesh_plink_fsm_restart(sta);
974 			break;
975 		case OPN_ACPT:
976 		case CNF_ACPT:
977 		case OPN_RJCT:
978 		case CNF_RJCT:
979 			action = WLAN_SP_MESH_PEERING_CLOSE;
980 			break;
981 		default:
982 			break;
983 		}
984 		break;
985 	default:
986 		/* should not get here, PLINK_BLOCKED is dealt with at the
987 		 * beginning of the function
988 		 */
989 		break;
990 	}
991 	spin_unlock_bh(&sta->mesh->plink_lock);
992 	if (flush)
993 		mesh_path_flush_by_nexthop(sta);
994 	if (action) {
995 		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
996 				    sta->mesh->llid, sta->mesh->plid,
997 				    sta->mesh->reason);
998 
999 		/* also send confirm in open case */
1000 		if (action == WLAN_SP_MESH_PEERING_OPEN) {
1001 			mesh_plink_frame_tx(sdata, sta,
1002 					    WLAN_SP_MESH_PEERING_CONFIRM,
1003 					    sta->sta.addr, sta->mesh->llid,
1004 					    sta->mesh->plid, 0);
1005 		}
1006 	}
1007 
1008 	return changed;
1009 }
1010 
1011 /*
1012  * mesh_plink_get_event - get correct MPM event
1013  *
1014  * @sdata: interface
1015  * @sta: peer, leave NULL if processing a frame from a new suitable peer
1016  * @elems: peering management IEs
1017  * @ftype: frame type
1018  * @llid: peer's peer link ID
1019  * @plid: peer's local link ID
1020  *
1021  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
1022  * an error.
1023  */
1024 static enum plink_event
1025 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
1026 		     struct sta_info *sta,
1027 		     struct ieee802_11_elems *elems,
1028 		     enum ieee80211_self_protected_actioncode ftype,
1029 		     u16 llid, u16 plid)
1030 {
1031 	enum plink_event event = PLINK_UNDEFINED;
1032 	u8 ie_len = elems->peering_len;
1033 	bool matches_local;
1034 
1035 	matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
1036 			 mesh_matches_local(sdata, elems));
1037 
1038 	/* deny open request from non-matching peer */
1039 	if (!matches_local && !sta) {
1040 		event = OPN_RJCT;
1041 		goto out;
1042 	}
1043 
1044 	if (!sta) {
1045 		if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
1046 			mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
1047 			goto out;
1048 		}
1049 		/* ftype == WLAN_SP_MESH_PEERING_OPEN */
1050 		if (!mesh_plink_free_count(sdata)) {
1051 			mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
1052 			goto out;
1053 		}
1054 
1055 		/* new matching peer */
1056 		event = OPN_ACPT;
1057 		goto out;
1058 	} else {
1059 		if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
1060 			mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
1061 			goto out;
1062 		}
1063 		if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
1064 			goto out;
1065 	}
1066 
1067 	switch (ftype) {
1068 	case WLAN_SP_MESH_PEERING_OPEN:
1069 		if (!matches_local)
1070 			event = OPN_RJCT;
1071 		if (!mesh_plink_free_count(sdata) ||
1072 		    (sta->mesh->plid && sta->mesh->plid != plid))
1073 			event = OPN_IGNR;
1074 		else
1075 			event = OPN_ACPT;
1076 		break;
1077 	case WLAN_SP_MESH_PEERING_CONFIRM:
1078 		if (!matches_local)
1079 			event = CNF_RJCT;
1080 		if (!mesh_plink_free_count(sdata) ||
1081 		    sta->mesh->llid != llid ||
1082 		    (sta->mesh->plid && sta->mesh->plid != plid))
1083 			event = CNF_IGNR;
1084 		else
1085 			event = CNF_ACPT;
1086 		break;
1087 	case WLAN_SP_MESH_PEERING_CLOSE:
1088 		if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1089 			/* Do not check for llid or plid. This does not
1090 			 * follow the standard but since multiple plinks
1091 			 * per sta are not supported, it is necessary in
1092 			 * order to avoid a livelock when MP A sees an
1093 			 * establish peer link to MP B but MP B does not
1094 			 * see it. This can be caused by a timeout in
1095 			 * B's peer link establishment or B beign
1096 			 * restarted.
1097 			 */
1098 			event = CLS_ACPT;
1099 		else if (sta->mesh->plid != plid)
1100 			event = CLS_IGNR;
1101 		else if (ie_len == 8 && sta->mesh->llid != llid)
1102 			event = CLS_IGNR;
1103 		else
1104 			event = CLS_ACPT;
1105 		break;
1106 	default:
1107 		mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1108 		break;
1109 	}
1110 
1111 out:
1112 	return event;
1113 }
1114 
1115 static void
1116 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1117 			 struct ieee80211_mgmt *mgmt,
1118 			 struct ieee802_11_elems *elems,
1119 			 struct ieee80211_rx_status *rx_status)
1120 {
1121 
1122 	struct sta_info *sta;
1123 	enum plink_event event;
1124 	enum ieee80211_self_protected_actioncode ftype;
1125 	u64 changed = 0;
1126 	u8 ie_len = elems->peering_len;
1127 	u16 plid, llid = 0;
1128 
1129 	if (!elems->peering) {
1130 		mpl_dbg(sdata,
1131 			"Mesh plink: missing necessary peer link ie\n");
1132 		return;
1133 	}
1134 
1135 	if (elems->rsn_len &&
1136 	    sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1137 		mpl_dbg(sdata,
1138 			"Mesh plink: can't establish link with secure peer\n");
1139 		return;
1140 	}
1141 
1142 	ftype = mgmt->u.action.u.self_prot.action_code;
1143 	if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1144 	    (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1145 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1146 							&& ie_len != 8)) {
1147 		mpl_dbg(sdata,
1148 			"Mesh plink: incorrect plink ie length %d %d\n",
1149 			ftype, ie_len);
1150 		return;
1151 	}
1152 
1153 	if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1154 	    (!elems->mesh_id || !elems->mesh_config)) {
1155 		mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1156 		return;
1157 	}
1158 	/* Note the lines below are correct, the llid in the frame is the plid
1159 	 * from the point of view of this host.
1160 	 */
1161 	plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1162 	if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1163 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1164 		llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1165 
1166 	/* WARNING: Only for sta pointer, is dropped & re-acquired */
1167 	rcu_read_lock();
1168 
1169 	sta = sta_info_get(sdata, mgmt->sa);
1170 
1171 	if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1172 	    !rssi_threshold_check(sdata, sta)) {
1173 		mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1174 			mgmt->sa);
1175 		goto unlock_rcu;
1176 	}
1177 
1178 	/* Now we will figure out the appropriate event... */
1179 	event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1180 
1181 	if (event == OPN_ACPT) {
1182 		rcu_read_unlock();
1183 		/* allocate sta entry if necessary and update info */
1184 		sta = mesh_sta_info_get(sdata, mgmt->sa, elems, rx_status);
1185 		if (!sta) {
1186 			mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1187 			goto unlock_rcu;
1188 		}
1189 		sta->mesh->plid = plid;
1190 	} else if (!sta && event == OPN_RJCT) {
1191 		mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1192 				    mgmt->sa, 0, plid,
1193 				    WLAN_REASON_MESH_CONFIG);
1194 		goto unlock_rcu;
1195 	} else if (!sta || event == PLINK_UNDEFINED) {
1196 		/* something went wrong */
1197 		goto unlock_rcu;
1198 	}
1199 
1200 	if (event == CNF_ACPT) {
1201 		/* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1202 		if (!sta->mesh->plid)
1203 			sta->mesh->plid = plid;
1204 
1205 		sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1206 	}
1207 
1208 	changed |= mesh_plink_fsm(sdata, sta, event);
1209 
1210 unlock_rcu:
1211 	rcu_read_unlock();
1212 
1213 	if (changed)
1214 		ieee80211_mbss_info_change_notify(sdata, changed);
1215 }
1216 
1217 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1218 			 struct ieee80211_mgmt *mgmt, size_t len,
1219 			 struct ieee80211_rx_status *rx_status)
1220 {
1221 	struct ieee802_11_elems *elems;
1222 	size_t baselen;
1223 	u8 *baseaddr;
1224 
1225 	/* need action_code, aux */
1226 	if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1227 		return;
1228 
1229 	if (sdata->u.mesh.user_mpm)
1230 		/* userspace must register for these */
1231 		return;
1232 
1233 	if (is_multicast_ether_addr(mgmt->da)) {
1234 		mpl_dbg(sdata,
1235 			"Mesh plink: ignore frame from multicast address\n");
1236 		return;
1237 	}
1238 
1239 	baseaddr = mgmt->u.action.u.self_prot.variable;
1240 	baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1241 	if (mgmt->u.action.u.self_prot.action_code ==
1242 						WLAN_SP_MESH_PEERING_CONFIRM) {
1243 		baseaddr += 4;
1244 		baselen += 4;
1245 
1246 		if (baselen > len)
1247 			return;
1248 	}
1249 	elems = ieee802_11_parse_elems(baseaddr, len - baselen, true, NULL);
1250 	mesh_process_plink_frame(sdata, mgmt, elems, rx_status);
1251 	kfree(elems);
1252 }
1253