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1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2008, 2009 open80211s Ltd.
4  * Copyright (C) 2019 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. */
rssi_threshold_check(struct ieee80211_sub_if_data * sdata,struct sta_info * sta)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->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  */
mesh_plink_fsm_restart(struct sta_info * sta)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  */
mesh_set_short_slot_time(struct ieee80211_sub_if_data * sdata)93 static u32 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, changed = 0;
99 	int i;
100 	bool short_slot = false;
101 
102 	sband = ieee80211_get_sband(sdata);
103 	if (!sband)
104 		return changed;
105 
106 	if (sband->band == NL80211_BAND_5GHZ) {
107 		/* (IEEE 802.11-2012 19.4.5) */
108 		short_slot = true;
109 		goto out;
110 	} else if (sband->band != NL80211_BAND_2GHZ) {
111 		goto out;
112 	}
113 
114 	for (i = 0; i < sband->n_bitrates; i++)
115 		if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
116 			erp_rates |= BIT(i);
117 
118 	if (!erp_rates)
119 		goto out;
120 
121 	rcu_read_lock();
122 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
123 		if (sdata != sta->sdata ||
124 		    sta->mesh->plink_state != NL80211_PLINK_ESTAB)
125 			continue;
126 
127 		short_slot = false;
128 		if (erp_rates & sta->sta.supp_rates[sband->band])
129 			short_slot = true;
130 		 else
131 			break;
132 	}
133 	rcu_read_unlock();
134 
135 out:
136 	if (sdata->vif.bss_conf.use_short_slot != short_slot) {
137 		sdata->vif.bss_conf.use_short_slot = short_slot;
138 		changed = BSS_CHANGED_ERP_SLOT;
139 		mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
140 			sdata->vif.addr, short_slot);
141 	}
142 	return changed;
143 }
144 
145 /**
146  * mesh_set_ht_prot_mode - set correct HT protection mode
147  * @sdata: the (mesh) interface to handle
148  *
149  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
150  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
151  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
152  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
153  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
154  * HT20 peer is present. Otherwise no-protection mode is selected.
155  */
mesh_set_ht_prot_mode(struct ieee80211_sub_if_data * sdata)156 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
157 {
158 	struct ieee80211_local *local = sdata->local;
159 	struct sta_info *sta;
160 	u16 ht_opmode;
161 	bool non_ht_sta = false, ht20_sta = false;
162 
163 	switch (sdata->vif.bss_conf.chandef.width) {
164 	case NL80211_CHAN_WIDTH_20_NOHT:
165 	case NL80211_CHAN_WIDTH_5:
166 	case NL80211_CHAN_WIDTH_10:
167 		return 0;
168 	default:
169 		break;
170 	}
171 
172 	rcu_read_lock();
173 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
174 		if (sdata != sta->sdata ||
175 		    sta->mesh->plink_state != NL80211_PLINK_ESTAB)
176 			continue;
177 
178 		if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
179 			continue;
180 
181 		if (!sta->sta.ht_cap.ht_supported) {
182 			mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
183 				       sta->sta.addr);
184 			non_ht_sta = true;
185 			break;
186 		}
187 
188 		mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
189 		ht20_sta = true;
190 	}
191 	rcu_read_unlock();
192 
193 	if (non_ht_sta)
194 		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
195 	else if (ht20_sta &&
196 		 sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
197 		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
198 	else
199 		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
200 
201 	if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
202 		return 0;
203 
204 	sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
205 	sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
206 	mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
207 	return BSS_CHANGED_HT;
208 }
209 
mesh_plink_frame_tx(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum ieee80211_self_protected_actioncode action,u8 * da,u16 llid,u16 plid,u16 reason)210 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
211 			       struct sta_info *sta,
212 			       enum ieee80211_self_protected_actioncode action,
213 			       u8 *da, u16 llid, u16 plid, u16 reason)
214 {
215 	struct ieee80211_local *local = sdata->local;
216 	struct sk_buff *skb;
217 	struct ieee80211_tx_info *info;
218 	struct ieee80211_mgmt *mgmt;
219 	bool include_plid = false;
220 	u16 peering_proto = 0;
221 	u8 *pos, ie_len = 4;
222 	u8 ie_len_he_cap;
223 	int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.self_prot);
224 	int err = -ENOMEM;
225 
226 	ie_len_he_cap = ieee80211_ie_len_he_cap(sdata,
227 						NL80211_IFTYPE_MESH_POINT);
228 	skb = dev_alloc_skb(local->tx_headroom +
229 			    hdr_len +
230 			    2 + /* capability info */
231 			    2 + /* AID */
232 			    2 + 8 + /* supported rates */
233 			    2 + (IEEE80211_MAX_SUPP_RATES - 8) +
234 			    2 + sdata->u.mesh.mesh_id_len +
235 			    2 + sizeof(struct ieee80211_meshconf_ie) +
236 			    2 + sizeof(struct ieee80211_ht_cap) +
237 			    2 + sizeof(struct ieee80211_ht_operation) +
238 			    2 + sizeof(struct ieee80211_vht_cap) +
239 			    2 + sizeof(struct ieee80211_vht_operation) +
240 			    ie_len_he_cap +
241 			    2 + 1 + sizeof(struct ieee80211_he_operation) +
242 				    sizeof(struct ieee80211_he_6ghz_oper) +
243 			    2 + 1 + sizeof(struct ieee80211_he_6ghz_capa) +
244 			    2 + 8 + /* peering IE */
245 			    sdata->u.mesh.ie_len);
246 	if (!skb)
247 		return err;
248 	info = IEEE80211_SKB_CB(skb);
249 	skb_reserve(skb, local->tx_headroom);
250 	mgmt = skb_put_zero(skb, hdr_len);
251 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
252 					  IEEE80211_STYPE_ACTION);
253 	memcpy(mgmt->da, da, ETH_ALEN);
254 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
255 	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
256 	mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
257 	mgmt->u.action.u.self_prot.action_code = action;
258 
259 	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
260 		struct ieee80211_supported_band *sband;
261 		enum nl80211_band band;
262 
263 		sband = ieee80211_get_sband(sdata);
264 		if (!sband) {
265 			err = -EINVAL;
266 			goto free;
267 		}
268 		band = sband->band;
269 
270 		/* capability info */
271 		pos = skb_put_zero(skb, 2);
272 		if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
273 			/* AID */
274 			pos = skb_put(skb, 2);
275 			put_unaligned_le16(sta->sta.aid, pos);
276 		}
277 		if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
278 		    ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
279 		    mesh_add_rsn_ie(sdata, skb) ||
280 		    mesh_add_meshid_ie(sdata, skb) ||
281 		    mesh_add_meshconf_ie(sdata, skb))
282 			goto free;
283 	} else {	/* WLAN_SP_MESH_PEERING_CLOSE */
284 		info->flags |= IEEE80211_TX_CTL_NO_ACK;
285 		if (mesh_add_meshid_ie(sdata, skb))
286 			goto free;
287 	}
288 
289 	/* Add Mesh Peering Management element */
290 	switch (action) {
291 	case WLAN_SP_MESH_PEERING_OPEN:
292 		break;
293 	case WLAN_SP_MESH_PEERING_CONFIRM:
294 		ie_len += 2;
295 		include_plid = true;
296 		break;
297 	case WLAN_SP_MESH_PEERING_CLOSE:
298 		if (plid) {
299 			ie_len += 2;
300 			include_plid = true;
301 		}
302 		ie_len += 2;	/* reason code */
303 		break;
304 	default:
305 		err = -EINVAL;
306 		goto free;
307 	}
308 
309 	if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
310 		goto free;
311 
312 	pos = skb_put(skb, 2 + ie_len);
313 	*pos++ = WLAN_EID_PEER_MGMT;
314 	*pos++ = ie_len;
315 	memcpy(pos, &peering_proto, 2);
316 	pos += 2;
317 	put_unaligned_le16(llid, pos);
318 	pos += 2;
319 	if (include_plid) {
320 		put_unaligned_le16(plid, pos);
321 		pos += 2;
322 	}
323 	if (action == WLAN_SP_MESH_PEERING_CLOSE) {
324 		put_unaligned_le16(reason, pos);
325 		pos += 2;
326 	}
327 
328 	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
329 		if (mesh_add_ht_cap_ie(sdata, skb) ||
330 		    mesh_add_ht_oper_ie(sdata, skb) ||
331 		    mesh_add_vht_cap_ie(sdata, skb) ||
332 		    mesh_add_vht_oper_ie(sdata, skb) ||
333 		    mesh_add_he_cap_ie(sdata, skb, ie_len_he_cap) ||
334 		    mesh_add_he_oper_ie(sdata, skb) ||
335 		    mesh_add_he_6ghz_cap_ie(sdata, skb))
336 			goto free;
337 	}
338 
339 	if (mesh_add_vendor_ies(sdata, skb))
340 		goto free;
341 
342 	ieee80211_tx_skb(sdata, skb);
343 	return 0;
344 free:
345 	kfree_skb(skb);
346 	return err;
347 }
348 
349 /**
350  * __mesh_plink_deactivate - deactivate mesh peer link
351  *
352  * @sta: mesh peer link to deactivate
353  *
354  * Mesh paths with this peer as next hop should be flushed
355  * by the caller outside of plink_lock.
356  *
357  * Returns beacon changed flag if the beacon content changed.
358  *
359  * Locking: the caller must hold sta->mesh->plink_lock
360  */
__mesh_plink_deactivate(struct sta_info * sta)361 static u32 __mesh_plink_deactivate(struct sta_info *sta)
362 {
363 	struct ieee80211_sub_if_data *sdata = sta->sdata;
364 	u32 changed = 0;
365 
366 	lockdep_assert_held(&sta->mesh->plink_lock);
367 
368 	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
369 		changed = mesh_plink_dec_estab_count(sdata);
370 	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
371 
372 	ieee80211_mps_sta_status_update(sta);
373 	changed |= ieee80211_mps_set_sta_local_pm(sta,
374 			NL80211_MESH_POWER_UNKNOWN);
375 
376 	return changed;
377 }
378 
379 /**
380  * mesh_plink_deactivate - deactivate mesh peer link
381  *
382  * @sta: mesh peer link to deactivate
383  *
384  * All mesh paths with this peer as next hop will be flushed
385  */
mesh_plink_deactivate(struct sta_info * sta)386 u32 mesh_plink_deactivate(struct sta_info *sta)
387 {
388 	struct ieee80211_sub_if_data *sdata = sta->sdata;
389 	u32 changed;
390 
391 	spin_lock_bh(&sta->mesh->plink_lock);
392 	changed = __mesh_plink_deactivate(sta);
393 
394 	if (!sdata->u.mesh.user_mpm) {
395 		sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
396 		mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
397 				    sta->sta.addr, sta->mesh->llid,
398 				    sta->mesh->plid, sta->mesh->reason);
399 	}
400 	spin_unlock_bh(&sta->mesh->plink_lock);
401 	if (!sdata->u.mesh.user_mpm)
402 		del_timer_sync(&sta->mesh->plink_timer);
403 	mesh_path_flush_by_nexthop(sta);
404 
405 	/* make sure no readers can access nexthop sta from here on */
406 	synchronize_net();
407 
408 	return changed;
409 }
410 
mesh_sta_info_init(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,struct ieee802_11_elems * elems)411 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
412 			       struct sta_info *sta,
413 			       struct ieee802_11_elems *elems)
414 {
415 	struct ieee80211_local *local = sdata->local;
416 	struct ieee80211_supported_band *sband;
417 	u32 rates, basic_rates = 0, changed = 0;
418 	enum ieee80211_sta_rx_bandwidth bw = sta->sta.bandwidth;
419 
420 	sband = ieee80211_get_sband(sdata);
421 	if (!sband)
422 		return;
423 
424 	rates = ieee80211_sta_get_rates(sdata, elems, sband->band,
425 					&basic_rates);
426 
427 	spin_lock_bh(&sta->mesh->plink_lock);
428 	sta->rx_stats.last_rx = jiffies;
429 
430 	/* rates and capabilities don't change during peering */
431 	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
432 	    sta->mesh->processed_beacon)
433 		goto out;
434 	sta->mesh->processed_beacon = true;
435 
436 	if (sta->sta.supp_rates[sband->band] != rates)
437 		changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
438 	sta->sta.supp_rates[sband->band] = rates;
439 
440 	if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
441 					      elems->ht_cap_elem, sta))
442 		changed |= IEEE80211_RC_BW_CHANGED;
443 
444 	ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
445 					    elems->vht_cap_elem, sta);
446 
447 	ieee80211_he_cap_ie_to_sta_he_cap(sdata, sband, elems->he_cap,
448 					  elems->he_cap_len,
449 					  elems->he_6ghz_capa,
450 					  sta);
451 
452 	if (bw != sta->sta.bandwidth)
453 		changed |= IEEE80211_RC_BW_CHANGED;
454 
455 	/* HT peer is operating 20MHz-only */
456 	if (elems->ht_operation &&
457 	    !(elems->ht_operation->ht_param &
458 	      IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
459 		if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
460 			changed |= IEEE80211_RC_BW_CHANGED;
461 		sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
462 	}
463 
464 	if (!test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
465 		rate_control_rate_init(sta);
466 	else
467 		rate_control_rate_update(local, sband, sta, changed);
468 out:
469 	spin_unlock_bh(&sta->mesh->plink_lock);
470 }
471 
mesh_allocate_aid(struct ieee80211_sub_if_data * sdata)472 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
473 {
474 	struct sta_info *sta;
475 	unsigned long *aid_map;
476 	int aid;
477 
478 	aid_map = kcalloc(BITS_TO_LONGS(IEEE80211_MAX_AID + 1),
479 			  sizeof(*aid_map), GFP_KERNEL);
480 	if (!aid_map)
481 		return -ENOMEM;
482 
483 	/* reserve aid 0 for mcast indication */
484 	__set_bit(0, aid_map);
485 
486 	rcu_read_lock();
487 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
488 		__set_bit(sta->sta.aid, aid_map);
489 	rcu_read_unlock();
490 
491 	aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
492 	kfree(aid_map);
493 
494 	if (aid > IEEE80211_MAX_AID)
495 		return -ENOBUFS;
496 
497 	return aid;
498 }
499 
500 static struct sta_info *
__mesh_sta_info_alloc(struct ieee80211_sub_if_data * sdata,u8 * hw_addr)501 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
502 {
503 	struct sta_info *sta;
504 	int aid;
505 
506 	if (sdata->local->num_sta >= MESH_MAX_PLINKS)
507 		return NULL;
508 
509 	aid = mesh_allocate_aid(sdata);
510 	if (aid < 0)
511 		return NULL;
512 
513 	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
514 	if (!sta)
515 		return NULL;
516 
517 	sta->mesh->plink_state = NL80211_PLINK_LISTEN;
518 	sta->sta.wme = true;
519 	sta->sta.aid = aid;
520 
521 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
522 	sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
523 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
524 
525 	return sta;
526 }
527 
528 static struct sta_info *
mesh_sta_info_alloc(struct ieee80211_sub_if_data * sdata,u8 * addr,struct ieee802_11_elems * elems,struct ieee80211_rx_status * rx_status)529 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
530 		    struct ieee802_11_elems *elems,
531 		    struct ieee80211_rx_status *rx_status)
532 {
533 	struct sta_info *sta = NULL;
534 
535 	/* Userspace handles station allocation */
536 	if (sdata->u.mesh.user_mpm ||
537 	    sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
538 		if (mesh_peer_accepts_plinks(elems) &&
539 		    mesh_plink_availables(sdata)) {
540 			int sig = 0;
541 
542 			if (ieee80211_hw_check(&sdata->local->hw, SIGNAL_DBM))
543 				sig = rx_status->signal;
544 
545 			cfg80211_notify_new_peer_candidate(sdata->dev, addr,
546 							   elems->ie_start,
547 							   elems->total_len,
548 							   sig, GFP_KERNEL);
549 		}
550 	} else
551 		sta = __mesh_sta_info_alloc(sdata, addr);
552 
553 	return sta;
554 }
555 
556 /*
557  * mesh_sta_info_get - return mesh sta info entry for @addr.
558  *
559  * @sdata: local meshif
560  * @addr: peer's address
561  * @elems: IEs from beacon or mesh peering frame.
562  * @rx_status: rx status for the frame for signal reporting
563  *
564  * Return existing or newly allocated sta_info under RCU read lock.
565  * (re)initialize with given IEs.
566  */
567 static struct sta_info *
mesh_sta_info_get(struct ieee80211_sub_if_data * sdata,u8 * addr,struct ieee802_11_elems * elems,struct ieee80211_rx_status * rx_status)568 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
569 		  u8 *addr, struct ieee802_11_elems *elems,
570 		  struct ieee80211_rx_status *rx_status) __acquires(RCU)
571 {
572 	struct sta_info *sta = NULL;
573 
574 	rcu_read_lock();
575 	sta = sta_info_get(sdata, addr);
576 	if (sta) {
577 		mesh_sta_info_init(sdata, sta, elems);
578 	} else {
579 		rcu_read_unlock();
580 		/* can't run atomic */
581 		sta = mesh_sta_info_alloc(sdata, addr, elems, rx_status);
582 		if (!sta) {
583 			rcu_read_lock();
584 			return NULL;
585 		}
586 
587 		mesh_sta_info_init(sdata, sta, elems);
588 
589 		if (sta_info_insert_rcu(sta))
590 			return NULL;
591 	}
592 
593 	return sta;
594 }
595 
596 /*
597  * mesh_neighbour_update - update or initialize new mesh neighbor.
598  *
599  * @sdata: local meshif
600  * @addr: peer's address
601  * @elems: IEs from beacon or mesh peering frame
602  * @rx_status: rx status for the frame for signal reporting
603  *
604  * Initiates peering if appropriate.
605  */
mesh_neighbour_update(struct ieee80211_sub_if_data * sdata,u8 * hw_addr,struct ieee802_11_elems * elems,struct ieee80211_rx_status * rx_status)606 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
607 			   u8 *hw_addr,
608 			   struct ieee802_11_elems *elems,
609 			   struct ieee80211_rx_status *rx_status)
610 {
611 	struct sta_info *sta;
612 	u32 changed = 0;
613 
614 	sta = mesh_sta_info_get(sdata, hw_addr, elems, rx_status);
615 	if (!sta)
616 		goto out;
617 
618 	sta->mesh->connected_to_gate = elems->mesh_config->meshconf_form &
619 		IEEE80211_MESHCONF_FORM_CONNECTED_TO_GATE;
620 
621 	if (mesh_peer_accepts_plinks(elems) &&
622 	    sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
623 	    sdata->u.mesh.accepting_plinks &&
624 	    sdata->u.mesh.mshcfg.auto_open_plinks &&
625 	    rssi_threshold_check(sdata, sta))
626 		changed = mesh_plink_open(sta);
627 
628 	ieee80211_mps_frame_release(sta, elems);
629 out:
630 	rcu_read_unlock();
631 	ieee80211_mbss_info_change_notify(sdata, changed);
632 }
633 
mesh_plink_timer(struct timer_list * t)634 void mesh_plink_timer(struct timer_list *t)
635 {
636 	struct mesh_sta *mesh = from_timer(mesh, t, plink_timer);
637 	struct sta_info *sta;
638 	u16 reason = 0;
639 	struct ieee80211_sub_if_data *sdata;
640 	struct mesh_config *mshcfg;
641 	enum ieee80211_self_protected_actioncode action = 0;
642 
643 	/*
644 	 * This STA is valid because sta_info_destroy() will
645 	 * del_timer_sync() this timer after having made sure
646 	 * it cannot be readded (by deleting the plink.)
647 	 */
648 	sta = mesh->plink_sta;
649 
650 	if (sta->sdata->local->quiescing)
651 		return;
652 
653 	spin_lock_bh(&sta->mesh->plink_lock);
654 
655 	/* If a timer fires just before a state transition on another CPU,
656 	 * we may have already extended the timeout and changed state by the
657 	 * time we've acquired the lock and arrived  here.  In that case,
658 	 * skip this timer and wait for the new one.
659 	 */
660 	if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
661 		mpl_dbg(sta->sdata,
662 			"Ignoring timer for %pM in state %s (timer adjusted)",
663 			sta->sta.addr, mplstates[sta->mesh->plink_state]);
664 		spin_unlock_bh(&sta->mesh->plink_lock);
665 		return;
666 	}
667 
668 	/* del_timer() and handler may race when entering these states */
669 	if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
670 	    sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
671 		mpl_dbg(sta->sdata,
672 			"Ignoring timer for %pM in state %s (timer deleted)",
673 			sta->sta.addr, mplstates[sta->mesh->plink_state]);
674 		spin_unlock_bh(&sta->mesh->plink_lock);
675 		return;
676 	}
677 
678 	mpl_dbg(sta->sdata,
679 		"Mesh plink timer for %pM fired on state %s\n",
680 		sta->sta.addr, mplstates[sta->mesh->plink_state]);
681 	sdata = sta->sdata;
682 	mshcfg = &sdata->u.mesh.mshcfg;
683 
684 	switch (sta->mesh->plink_state) {
685 	case NL80211_PLINK_OPN_RCVD:
686 	case NL80211_PLINK_OPN_SNT:
687 		/* retry timer */
688 		if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
689 			u32 rand;
690 			mpl_dbg(sta->sdata,
691 				"Mesh plink for %pM (retry, timeout): %d %d\n",
692 				sta->sta.addr, sta->mesh->plink_retries,
693 				sta->mesh->plink_timeout);
694 			get_random_bytes(&rand, sizeof(u32));
695 			sta->mesh->plink_timeout = sta->mesh->plink_timeout +
696 					     rand % sta->mesh->plink_timeout;
697 			++sta->mesh->plink_retries;
698 			mod_plink_timer(sta, sta->mesh->plink_timeout);
699 			action = WLAN_SP_MESH_PEERING_OPEN;
700 			break;
701 		}
702 		reason = WLAN_REASON_MESH_MAX_RETRIES;
703 		fallthrough;
704 	case NL80211_PLINK_CNF_RCVD:
705 		/* confirm timer */
706 		if (!reason)
707 			reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
708 		sta->mesh->plink_state = NL80211_PLINK_HOLDING;
709 		mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
710 		action = WLAN_SP_MESH_PEERING_CLOSE;
711 		break;
712 	case NL80211_PLINK_HOLDING:
713 		/* holding timer */
714 		del_timer(&sta->mesh->plink_timer);
715 		mesh_plink_fsm_restart(sta);
716 		break;
717 	default:
718 		break;
719 	}
720 	spin_unlock_bh(&sta->mesh->plink_lock);
721 	if (action)
722 		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
723 				    sta->mesh->llid, sta->mesh->plid, reason);
724 }
725 
mesh_plink_timer_set(struct sta_info * sta,u32 timeout)726 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
727 {
728 	sta->mesh->plink_timeout = timeout;
729 	mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
730 }
731 
llid_in_use(struct ieee80211_sub_if_data * sdata,u16 llid)732 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
733 			u16 llid)
734 {
735 	struct ieee80211_local *local = sdata->local;
736 	bool in_use = false;
737 	struct sta_info *sta;
738 
739 	rcu_read_lock();
740 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
741 		if (sdata != sta->sdata)
742 			continue;
743 
744 		if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
745 			in_use = true;
746 			break;
747 		}
748 	}
749 	rcu_read_unlock();
750 
751 	return in_use;
752 }
753 
mesh_get_new_llid(struct ieee80211_sub_if_data * sdata)754 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
755 {
756 	u16 llid;
757 
758 	do {
759 		get_random_bytes(&llid, sizeof(llid));
760 	} while (llid_in_use(sdata, llid));
761 
762 	return llid;
763 }
764 
mesh_plink_open(struct sta_info * sta)765 u32 mesh_plink_open(struct sta_info *sta)
766 {
767 	struct ieee80211_sub_if_data *sdata = sta->sdata;
768 	u32 changed;
769 
770 	if (!test_sta_flag(sta, WLAN_STA_AUTH))
771 		return 0;
772 
773 	spin_lock_bh(&sta->mesh->plink_lock);
774 	sta->mesh->llid = mesh_get_new_llid(sdata);
775 	if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
776 	    sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
777 		spin_unlock_bh(&sta->mesh->plink_lock);
778 		return 0;
779 	}
780 	sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
781 	mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
782 	spin_unlock_bh(&sta->mesh->plink_lock);
783 	mpl_dbg(sdata,
784 		"Mesh plink: starting establishment with %pM\n",
785 		sta->sta.addr);
786 
787 	/* set the non-peer mode to active during peering */
788 	changed = ieee80211_mps_local_status_update(sdata);
789 
790 	mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
791 			    sta->sta.addr, sta->mesh->llid, 0, 0);
792 	return changed;
793 }
794 
mesh_plink_block(struct sta_info * sta)795 u32 mesh_plink_block(struct sta_info *sta)
796 {
797 	u32 changed;
798 
799 	spin_lock_bh(&sta->mesh->plink_lock);
800 	changed = __mesh_plink_deactivate(sta);
801 	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
802 	spin_unlock_bh(&sta->mesh->plink_lock);
803 	mesh_path_flush_by_nexthop(sta);
804 
805 	return changed;
806 }
807 
mesh_plink_close(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum plink_event event)808 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
809 			     struct sta_info *sta,
810 			     enum plink_event event)
811 {
812 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
813 	u16 reason = (event == CLS_ACPT) ?
814 		     WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
815 
816 	sta->mesh->reason = reason;
817 	sta->mesh->plink_state = NL80211_PLINK_HOLDING;
818 	mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
819 }
820 
mesh_plink_establish(struct ieee80211_sub_if_data * sdata,struct sta_info * sta)821 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
822 				struct sta_info *sta)
823 {
824 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
825 	u32 changed = 0;
826 
827 	del_timer(&sta->mesh->plink_timer);
828 	sta->mesh->plink_state = NL80211_PLINK_ESTAB;
829 	changed |= mesh_plink_inc_estab_count(sdata);
830 	changed |= mesh_set_ht_prot_mode(sdata);
831 	changed |= mesh_set_short_slot_time(sdata);
832 	mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
833 	ieee80211_mps_sta_status_update(sta);
834 	changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
835 	return changed;
836 }
837 
838 /**
839  * mesh_plink_fsm - step @sta MPM based on @event
840  *
841  * @sdata: interface
842  * @sta: mesh neighbor
843  * @event: peering event
844  *
845  * Return: changed MBSS flags
846  */
mesh_plink_fsm(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum plink_event event)847 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
848 			  struct sta_info *sta, enum plink_event event)
849 {
850 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
851 	enum ieee80211_self_protected_actioncode action = 0;
852 	u32 changed = 0;
853 	bool flush = false;
854 
855 	mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
856 		mplstates[sta->mesh->plink_state], mplevents[event]);
857 
858 	spin_lock_bh(&sta->mesh->plink_lock);
859 	switch (sta->mesh->plink_state) {
860 	case NL80211_PLINK_LISTEN:
861 		switch (event) {
862 		case CLS_ACPT:
863 			mesh_plink_fsm_restart(sta);
864 			break;
865 		case OPN_ACPT:
866 			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
867 			sta->mesh->llid = mesh_get_new_llid(sdata);
868 			mesh_plink_timer_set(sta,
869 					     mshcfg->dot11MeshRetryTimeout);
870 
871 			/* set the non-peer mode to active during peering */
872 			changed |= ieee80211_mps_local_status_update(sdata);
873 			action = WLAN_SP_MESH_PEERING_OPEN;
874 			break;
875 		default:
876 			break;
877 		}
878 		break;
879 	case NL80211_PLINK_OPN_SNT:
880 		switch (event) {
881 		case OPN_RJCT:
882 		case CNF_RJCT:
883 		case CLS_ACPT:
884 			mesh_plink_close(sdata, sta, event);
885 			action = WLAN_SP_MESH_PEERING_CLOSE;
886 			break;
887 		case OPN_ACPT:
888 			/* retry timer is left untouched */
889 			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
890 			action = WLAN_SP_MESH_PEERING_CONFIRM;
891 			break;
892 		case CNF_ACPT:
893 			sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
894 			mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
895 			break;
896 		default:
897 			break;
898 		}
899 		break;
900 	case NL80211_PLINK_OPN_RCVD:
901 		switch (event) {
902 		case OPN_RJCT:
903 		case CNF_RJCT:
904 		case CLS_ACPT:
905 			mesh_plink_close(sdata, sta, event);
906 			action = WLAN_SP_MESH_PEERING_CLOSE;
907 			break;
908 		case OPN_ACPT:
909 			action = WLAN_SP_MESH_PEERING_CONFIRM;
910 			break;
911 		case CNF_ACPT:
912 			changed |= mesh_plink_establish(sdata, sta);
913 			break;
914 		default:
915 			break;
916 		}
917 		break;
918 	case NL80211_PLINK_CNF_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 			changed |= mesh_plink_establish(sdata, sta);
928 			action = WLAN_SP_MESH_PEERING_CONFIRM;
929 			break;
930 		default:
931 			break;
932 		}
933 		break;
934 	case NL80211_PLINK_ESTAB:
935 		switch (event) {
936 		case CLS_ACPT:
937 			changed |= __mesh_plink_deactivate(sta);
938 			changed |= mesh_set_ht_prot_mode(sdata);
939 			changed |= mesh_set_short_slot_time(sdata);
940 			mesh_plink_close(sdata, sta, event);
941 			action = WLAN_SP_MESH_PEERING_CLOSE;
942 			flush = true;
943 			break;
944 		case OPN_ACPT:
945 			action = WLAN_SP_MESH_PEERING_CONFIRM;
946 			break;
947 		default:
948 			break;
949 		}
950 		break;
951 	case NL80211_PLINK_HOLDING:
952 		switch (event) {
953 		case CLS_ACPT:
954 			del_timer(&sta->mesh->plink_timer);
955 			mesh_plink_fsm_restart(sta);
956 			break;
957 		case OPN_ACPT:
958 		case CNF_ACPT:
959 		case OPN_RJCT:
960 		case CNF_RJCT:
961 			action = WLAN_SP_MESH_PEERING_CLOSE;
962 			break;
963 		default:
964 			break;
965 		}
966 		break;
967 	default:
968 		/* should not get here, PLINK_BLOCKED is dealt with at the
969 		 * beginning of the function
970 		 */
971 		break;
972 	}
973 	spin_unlock_bh(&sta->mesh->plink_lock);
974 	if (flush)
975 		mesh_path_flush_by_nexthop(sta);
976 	if (action) {
977 		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
978 				    sta->mesh->llid, sta->mesh->plid,
979 				    sta->mesh->reason);
980 
981 		/* also send confirm in open case */
982 		if (action == WLAN_SP_MESH_PEERING_OPEN) {
983 			mesh_plink_frame_tx(sdata, sta,
984 					    WLAN_SP_MESH_PEERING_CONFIRM,
985 					    sta->sta.addr, sta->mesh->llid,
986 					    sta->mesh->plid, 0);
987 		}
988 	}
989 
990 	return changed;
991 }
992 
993 /*
994  * mesh_plink_get_event - get correct MPM event
995  *
996  * @sdata: interface
997  * @sta: peer, leave NULL if processing a frame from a new suitable peer
998  * @elems: peering management IEs
999  * @ftype: frame type
1000  * @llid: peer's peer link ID
1001  * @plid: peer's local link ID
1002  *
1003  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
1004  * an error.
1005  */
1006 static enum plink_event
mesh_plink_get_event(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,struct ieee802_11_elems * elems,enum ieee80211_self_protected_actioncode ftype,u16 llid,u16 plid)1007 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
1008 		     struct sta_info *sta,
1009 		     struct ieee802_11_elems *elems,
1010 		     enum ieee80211_self_protected_actioncode ftype,
1011 		     u16 llid, u16 plid)
1012 {
1013 	enum plink_event event = PLINK_UNDEFINED;
1014 	u8 ie_len = elems->peering_len;
1015 	bool matches_local;
1016 
1017 	matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
1018 			 mesh_matches_local(sdata, elems));
1019 
1020 	/* deny open request from non-matching peer */
1021 	if (!matches_local && !sta) {
1022 		event = OPN_RJCT;
1023 		goto out;
1024 	}
1025 
1026 	if (!sta) {
1027 		if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
1028 			mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
1029 			goto out;
1030 		}
1031 		/* ftype == WLAN_SP_MESH_PEERING_OPEN */
1032 		if (!mesh_plink_free_count(sdata)) {
1033 			mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
1034 			goto out;
1035 		}
1036 
1037 		/* new matching peer */
1038 		event = OPN_ACPT;
1039 		goto out;
1040 	} else {
1041 		if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
1042 			mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
1043 			goto out;
1044 		}
1045 		if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
1046 			goto out;
1047 	}
1048 
1049 	switch (ftype) {
1050 	case WLAN_SP_MESH_PEERING_OPEN:
1051 		if (!matches_local)
1052 			event = OPN_RJCT;
1053 		else if (!mesh_plink_free_count(sdata) ||
1054 			 (sta->mesh->plid && sta->mesh->plid != plid))
1055 			event = OPN_IGNR;
1056 		else
1057 			event = OPN_ACPT;
1058 		break;
1059 	case WLAN_SP_MESH_PEERING_CONFIRM:
1060 		if (!matches_local)
1061 			event = CNF_RJCT;
1062 		else if (!mesh_plink_free_count(sdata) ||
1063 			 sta->mesh->llid != llid ||
1064 			 (sta->mesh->plid && sta->mesh->plid != plid))
1065 			event = CNF_IGNR;
1066 		else
1067 			event = CNF_ACPT;
1068 		break;
1069 	case WLAN_SP_MESH_PEERING_CLOSE:
1070 		if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1071 			/* Do not check for llid or plid. This does not
1072 			 * follow the standard but since multiple plinks
1073 			 * per sta are not supported, it is necessary in
1074 			 * order to avoid a livelock when MP A sees an
1075 			 * establish peer link to MP B but MP B does not
1076 			 * see it. This can be caused by a timeout in
1077 			 * B's peer link establishment or B beign
1078 			 * restarted.
1079 			 */
1080 			event = CLS_ACPT;
1081 		else if (sta->mesh->plid != plid)
1082 			event = CLS_IGNR;
1083 		else if (ie_len == 8 && sta->mesh->llid != llid)
1084 			event = CLS_IGNR;
1085 		else
1086 			event = CLS_ACPT;
1087 		break;
1088 	default:
1089 		mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1090 		break;
1091 	}
1092 
1093 out:
1094 	return event;
1095 }
1096 
1097 static void
mesh_process_plink_frame(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,struct ieee802_11_elems * elems,struct ieee80211_rx_status * rx_status)1098 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1099 			 struct ieee80211_mgmt *mgmt,
1100 			 struct ieee802_11_elems *elems,
1101 			 struct ieee80211_rx_status *rx_status)
1102 {
1103 
1104 	struct sta_info *sta;
1105 	enum plink_event event;
1106 	enum ieee80211_self_protected_actioncode ftype;
1107 	u32 changed = 0;
1108 	u8 ie_len = elems->peering_len;
1109 	u16 plid, llid = 0;
1110 
1111 	if (!elems->peering) {
1112 		mpl_dbg(sdata,
1113 			"Mesh plink: missing necessary peer link ie\n");
1114 		return;
1115 	}
1116 
1117 	if (elems->rsn_len &&
1118 	    sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1119 		mpl_dbg(sdata,
1120 			"Mesh plink: can't establish link with secure peer\n");
1121 		return;
1122 	}
1123 
1124 	ftype = mgmt->u.action.u.self_prot.action_code;
1125 	if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1126 	    (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1127 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1128 							&& ie_len != 8)) {
1129 		mpl_dbg(sdata,
1130 			"Mesh plink: incorrect plink ie length %d %d\n",
1131 			ftype, ie_len);
1132 		return;
1133 	}
1134 
1135 	if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1136 	    (!elems->mesh_id || !elems->mesh_config)) {
1137 		mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1138 		return;
1139 	}
1140 	/* Note the lines below are correct, the llid in the frame is the plid
1141 	 * from the point of view of this host.
1142 	 */
1143 	plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1144 	if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1145 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1146 		llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1147 
1148 	/* WARNING: Only for sta pointer, is dropped & re-acquired */
1149 	rcu_read_lock();
1150 
1151 	sta = sta_info_get(sdata, mgmt->sa);
1152 
1153 	if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1154 	    !rssi_threshold_check(sdata, sta)) {
1155 		mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1156 			mgmt->sa);
1157 		goto unlock_rcu;
1158 	}
1159 
1160 	/* Now we will figure out the appropriate event... */
1161 	event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1162 
1163 	if (event == OPN_ACPT) {
1164 		rcu_read_unlock();
1165 		/* allocate sta entry if necessary and update info */
1166 		sta = mesh_sta_info_get(sdata, mgmt->sa, elems, rx_status);
1167 		if (!sta) {
1168 			mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1169 			goto unlock_rcu;
1170 		}
1171 		sta->mesh->plid = plid;
1172 	} else if (!sta && event == OPN_RJCT) {
1173 		mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1174 				    mgmt->sa, 0, plid,
1175 				    WLAN_REASON_MESH_CONFIG);
1176 		goto unlock_rcu;
1177 	} else if (!sta || event == PLINK_UNDEFINED) {
1178 		/* something went wrong */
1179 		goto unlock_rcu;
1180 	}
1181 
1182 	if (event == CNF_ACPT) {
1183 		/* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1184 		if (!sta->mesh->plid)
1185 			sta->mesh->plid = plid;
1186 
1187 		sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1188 	}
1189 
1190 	changed |= mesh_plink_fsm(sdata, sta, event);
1191 
1192 unlock_rcu:
1193 	rcu_read_unlock();
1194 
1195 	if (changed)
1196 		ieee80211_mbss_info_change_notify(sdata, changed);
1197 }
1198 
mesh_rx_plink_frame(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,size_t len,struct ieee80211_rx_status * rx_status)1199 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1200 			 struct ieee80211_mgmt *mgmt, size_t len,
1201 			 struct ieee80211_rx_status *rx_status)
1202 {
1203 	struct ieee802_11_elems elems;
1204 	size_t baselen;
1205 	u8 *baseaddr;
1206 
1207 	/* need action_code, aux */
1208 	if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1209 		return;
1210 
1211 	if (sdata->u.mesh.user_mpm)
1212 		/* userspace must register for these */
1213 		return;
1214 
1215 	if (is_multicast_ether_addr(mgmt->da)) {
1216 		mpl_dbg(sdata,
1217 			"Mesh plink: ignore frame from multicast address\n");
1218 		return;
1219 	}
1220 
1221 	baseaddr = mgmt->u.action.u.self_prot.variable;
1222 	baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1223 	if (mgmt->u.action.u.self_prot.action_code ==
1224 						WLAN_SP_MESH_PEERING_CONFIRM) {
1225 		baseaddr += 4;
1226 		baselen += 4;
1227 
1228 		if (baselen > len)
1229 			return;
1230 	}
1231 	ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems,
1232 			       mgmt->bssid, NULL);
1233 	mesh_process_plink_frame(sdata, mgmt, &elems, rx_status);
1234 }
1235