xref: /openbmc/linux/net/mac80211/mesh_plink.c (revision 26479609)
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. */
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->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  */
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 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  */
mesh_set_ht_prot_mode(struct ieee80211_sub_if_data * sdata)157 static u64 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
158 {
159 	struct ieee80211_local *local = sdata->local;
160 	struct sta_info *sta;
161 	u16 ht_opmode;
162 	bool non_ht_sta = false, ht20_sta = false;
163 
164 	switch (sdata->vif.bss_conf.chandef.width) {
165 	case NL80211_CHAN_WIDTH_20_NOHT:
166 	case NL80211_CHAN_WIDTH_5:
167 	case NL80211_CHAN_WIDTH_10:
168 		return 0;
169 	default:
170 		break;
171 	}
172 
173 	rcu_read_lock();
174 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
175 		if (sdata != sta->sdata ||
176 		    sta->mesh->plink_state != NL80211_PLINK_ESTAB)
177 			continue;
178 
179 		if (sta->sta.deflink.bandwidth > IEEE80211_STA_RX_BW_20)
180 			continue;
181 
182 		if (!sta->sta.deflink.ht_cap.ht_supported) {
183 			mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
184 				       sta->sta.addr);
185 			non_ht_sta = true;
186 			break;
187 		}
188 
189 		mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
190 		ht20_sta = true;
191 	}
192 	rcu_read_unlock();
193 
194 	if (non_ht_sta)
195 		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
196 	else if (ht20_sta &&
197 		 sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
198 		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
199 	else
200 		ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
201 
202 	if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
203 		return 0;
204 
205 	sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
206 	sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
207 	mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
208 	return BSS_CHANGED_HT;
209 }
210 
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)211 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
212 			       struct sta_info *sta,
213 			       enum ieee80211_self_protected_actioncode action,
214 			       u8 *da, u16 llid, u16 plid, u16 reason)
215 {
216 	struct ieee80211_local *local = sdata->local;
217 	struct sk_buff *skb;
218 	struct ieee80211_tx_info *info;
219 	struct ieee80211_mgmt *mgmt;
220 	bool include_plid = false;
221 	u16 peering_proto = 0;
222 	u8 *pos, ie_len = 4;
223 	u8 ie_len_he_cap, ie_len_eht_cap;
224 	int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.self_prot);
225 	int err = -ENOMEM;
226 
227 	ie_len_he_cap = ieee80211_ie_len_he_cap(sdata,
228 						NL80211_IFTYPE_MESH_POINT);
229 	ie_len_eht_cap = ieee80211_ie_len_eht_cap(sdata,
230 						  NL80211_IFTYPE_MESH_POINT);
231 	skb = dev_alloc_skb(local->tx_headroom +
232 			    hdr_len +
233 			    2 + /* capability info */
234 			    2 + /* AID */
235 			    2 + 8 + /* supported rates */
236 			    2 + (IEEE80211_MAX_SUPP_RATES - 8) +
237 			    2 + sdata->u.mesh.mesh_id_len +
238 			    2 + sizeof(struct ieee80211_meshconf_ie) +
239 			    2 + sizeof(struct ieee80211_ht_cap) +
240 			    2 + sizeof(struct ieee80211_ht_operation) +
241 			    2 + sizeof(struct ieee80211_vht_cap) +
242 			    2 + sizeof(struct ieee80211_vht_operation) +
243 			    ie_len_he_cap +
244 			    2 + 1 + sizeof(struct ieee80211_he_operation) +
245 				    sizeof(struct ieee80211_he_6ghz_oper) +
246 			    2 + 1 + sizeof(struct ieee80211_he_6ghz_capa) +
247 			    ie_len_eht_cap +
248 			    2 + 1 + offsetof(struct ieee80211_eht_operation, optional) +
249 				    offsetof(struct ieee80211_eht_operation_info, optional) +
250 			    2 + 8 + /* peering IE */
251 			    sdata->u.mesh.ie_len);
252 	if (!skb)
253 		return err;
254 	info = IEEE80211_SKB_CB(skb);
255 	skb_reserve(skb, local->tx_headroom);
256 	mgmt = skb_put_zero(skb, hdr_len);
257 	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
258 					  IEEE80211_STYPE_ACTION);
259 	memcpy(mgmt->da, da, ETH_ALEN);
260 	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
261 	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
262 	mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
263 	mgmt->u.action.u.self_prot.action_code = action;
264 
265 	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
266 		struct ieee80211_supported_band *sband;
267 		enum nl80211_band band;
268 
269 		sband = ieee80211_get_sband(sdata);
270 		if (!sband) {
271 			err = -EINVAL;
272 			goto free;
273 		}
274 		band = sband->band;
275 
276 		/* capability info */
277 		pos = skb_put_zero(skb, 2);
278 		if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
279 			/* AID */
280 			pos = skb_put(skb, 2);
281 			put_unaligned_le16(sta->sta.aid, pos);
282 		}
283 		if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
284 		    ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
285 		    mesh_add_rsn_ie(sdata, skb) ||
286 		    mesh_add_meshid_ie(sdata, skb) ||
287 		    mesh_add_meshconf_ie(sdata, skb))
288 			goto free;
289 	} else {	/* WLAN_SP_MESH_PEERING_CLOSE */
290 		info->flags |= IEEE80211_TX_CTL_NO_ACK;
291 		if (mesh_add_meshid_ie(sdata, skb))
292 			goto free;
293 	}
294 
295 	/* Add Mesh Peering Management element */
296 	switch (action) {
297 	case WLAN_SP_MESH_PEERING_OPEN:
298 		break;
299 	case WLAN_SP_MESH_PEERING_CONFIRM:
300 		ie_len += 2;
301 		include_plid = true;
302 		break;
303 	case WLAN_SP_MESH_PEERING_CLOSE:
304 		if (plid) {
305 			ie_len += 2;
306 			include_plid = true;
307 		}
308 		ie_len += 2;	/* reason code */
309 		break;
310 	default:
311 		err = -EINVAL;
312 		goto free;
313 	}
314 
315 	if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
316 		goto free;
317 
318 	pos = skb_put(skb, 2 + ie_len);
319 	*pos++ = WLAN_EID_PEER_MGMT;
320 	*pos++ = ie_len;
321 	memcpy(pos, &peering_proto, 2);
322 	pos += 2;
323 	put_unaligned_le16(llid, pos);
324 	pos += 2;
325 	if (include_plid) {
326 		put_unaligned_le16(plid, pos);
327 		pos += 2;
328 	}
329 	if (action == WLAN_SP_MESH_PEERING_CLOSE) {
330 		put_unaligned_le16(reason, pos);
331 		pos += 2;
332 	}
333 
334 	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
335 		if (mesh_add_ht_cap_ie(sdata, skb) ||
336 		    mesh_add_ht_oper_ie(sdata, skb) ||
337 		    mesh_add_vht_cap_ie(sdata, skb) ||
338 		    mesh_add_vht_oper_ie(sdata, skb) ||
339 		    mesh_add_he_cap_ie(sdata, skb, ie_len_he_cap) ||
340 		    mesh_add_he_oper_ie(sdata, skb) ||
341 		    mesh_add_he_6ghz_cap_ie(sdata, skb) ||
342 		    mesh_add_eht_cap_ie(sdata, skb, ie_len_eht_cap) ||
343 		    mesh_add_eht_oper_ie(sdata, skb))
344 			goto free;
345 	}
346 
347 	if (mesh_add_vendor_ies(sdata, skb))
348 		goto free;
349 
350 	ieee80211_tx_skb(sdata, skb);
351 	return 0;
352 free:
353 	kfree_skb(skb);
354 	return err;
355 }
356 
357 /**
358  * __mesh_plink_deactivate - deactivate mesh peer link
359  *
360  * @sta: mesh peer link to deactivate
361  *
362  * Mesh paths with this peer as next hop should be flushed
363  * by the caller outside of plink_lock.
364  *
365  * Returns beacon changed flag if the beacon content changed.
366  *
367  * Locking: the caller must hold sta->mesh->plink_lock
368  */
__mesh_plink_deactivate(struct sta_info * sta)369 static u64 __mesh_plink_deactivate(struct sta_info *sta)
370 {
371 	struct ieee80211_sub_if_data *sdata = sta->sdata;
372 	u64 changed = 0;
373 
374 	lockdep_assert_held(&sta->mesh->plink_lock);
375 
376 	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
377 		changed = mesh_plink_dec_estab_count(sdata);
378 	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
379 
380 	ieee80211_mps_sta_status_update(sta);
381 	changed |= ieee80211_mps_set_sta_local_pm(sta,
382 			NL80211_MESH_POWER_UNKNOWN);
383 
384 	return changed;
385 }
386 
387 /**
388  * mesh_plink_deactivate - deactivate mesh peer link
389  *
390  * @sta: mesh peer link to deactivate
391  *
392  * All mesh paths with this peer as next hop will be flushed
393  */
mesh_plink_deactivate(struct sta_info * sta)394 u64 mesh_plink_deactivate(struct sta_info *sta)
395 {
396 	struct ieee80211_sub_if_data *sdata = sta->sdata;
397 	u64 changed;
398 
399 	spin_lock_bh(&sta->mesh->plink_lock);
400 	changed = __mesh_plink_deactivate(sta);
401 
402 	if (!sdata->u.mesh.user_mpm) {
403 		sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
404 		mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
405 				    sta->sta.addr, sta->mesh->llid,
406 				    sta->mesh->plid, sta->mesh->reason);
407 	}
408 	spin_unlock_bh(&sta->mesh->plink_lock);
409 	if (!sdata->u.mesh.user_mpm)
410 		del_timer_sync(&sta->mesh->plink_timer);
411 	mesh_path_flush_by_nexthop(sta);
412 
413 	/* make sure no readers can access nexthop sta from here on */
414 	synchronize_net();
415 
416 	return changed;
417 }
418 
mesh_sta_info_init(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,struct ieee802_11_elems * elems)419 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
420 			       struct sta_info *sta,
421 			       struct ieee802_11_elems *elems)
422 {
423 	struct ieee80211_local *local = sdata->local;
424 	struct ieee80211_supported_band *sband;
425 	u32 rates, basic_rates = 0, changed = 0;
426 	enum ieee80211_sta_rx_bandwidth bw = sta->sta.deflink.bandwidth;
427 
428 	sband = ieee80211_get_sband(sdata);
429 	if (!sband)
430 		return;
431 
432 	rates = ieee80211_sta_get_rates(sdata, elems, sband->band,
433 					&basic_rates);
434 
435 	spin_lock_bh(&sta->mesh->plink_lock);
436 	sta->deflink.rx_stats.last_rx = jiffies;
437 
438 	/* rates and capabilities don't change during peering */
439 	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
440 	    sta->mesh->processed_beacon)
441 		goto out;
442 	sta->mesh->processed_beacon = true;
443 
444 	if (sta->sta.deflink.supp_rates[sband->band] != rates)
445 		changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
446 	sta->sta.deflink.supp_rates[sband->band] = rates;
447 
448 	if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
449 					      elems->ht_cap_elem,
450 					      &sta->deflink))
451 		changed |= IEEE80211_RC_BW_CHANGED;
452 
453 	ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
454 					    elems->vht_cap_elem, NULL,
455 					    &sta->deflink);
456 
457 	ieee80211_he_cap_ie_to_sta_he_cap(sdata, sband, elems->he_cap,
458 					  elems->he_cap_len,
459 					  elems->he_6ghz_capa,
460 					  &sta->deflink);
461 
462 	ieee80211_eht_cap_ie_to_sta_eht_cap(sdata, sband, elems->he_cap,
463 					    elems->he_cap_len,
464 					    elems->eht_cap, elems->eht_cap_len,
465 					    &sta->deflink);
466 
467 	if (bw != sta->sta.deflink.bandwidth)
468 		changed |= IEEE80211_RC_BW_CHANGED;
469 
470 	/* HT peer is operating 20MHz-only */
471 	if (elems->ht_operation &&
472 	    !(elems->ht_operation->ht_param &
473 	      IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
474 		if (sta->sta.deflink.bandwidth != IEEE80211_STA_RX_BW_20)
475 			changed |= IEEE80211_RC_BW_CHANGED;
476 		sta->sta.deflink.bandwidth = IEEE80211_STA_RX_BW_20;
477 	}
478 
479 	if (!test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
480 		rate_control_rate_init(sta);
481 	else
482 		rate_control_rate_update(local, sband, sta, 0, changed);
483 out:
484 	spin_unlock_bh(&sta->mesh->plink_lock);
485 }
486 
mesh_allocate_aid(struct ieee80211_sub_if_data * sdata)487 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
488 {
489 	struct sta_info *sta;
490 	unsigned long *aid_map;
491 	int aid;
492 
493 	aid_map = bitmap_zalloc(IEEE80211_MAX_AID + 1, GFP_KERNEL);
494 	if (!aid_map)
495 		return -ENOMEM;
496 
497 	/* reserve aid 0 for mcast indication */
498 	__set_bit(0, aid_map);
499 
500 	rcu_read_lock();
501 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
502 		__set_bit(sta->sta.aid, aid_map);
503 	rcu_read_unlock();
504 
505 	aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
506 	bitmap_free(aid_map);
507 
508 	if (aid > IEEE80211_MAX_AID)
509 		return -ENOBUFS;
510 
511 	return aid;
512 }
513 
514 static struct sta_info *
__mesh_sta_info_alloc(struct ieee80211_sub_if_data * sdata,u8 * hw_addr)515 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
516 {
517 	struct sta_info *sta;
518 	int aid;
519 
520 	if (sdata->local->num_sta >= MESH_MAX_PLINKS)
521 		return NULL;
522 
523 	aid = mesh_allocate_aid(sdata);
524 	if (aid < 0)
525 		return NULL;
526 
527 	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
528 	if (!sta)
529 		return NULL;
530 
531 	sta->mesh->plink_state = NL80211_PLINK_LISTEN;
532 	sta->sta.wme = true;
533 	sta->sta.aid = aid;
534 
535 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
536 	sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
537 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
538 
539 	return sta;
540 }
541 
542 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)543 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
544 		    struct ieee802_11_elems *elems,
545 		    struct ieee80211_rx_status *rx_status)
546 {
547 	struct sta_info *sta = NULL;
548 
549 	/* Userspace handles station allocation */
550 	if (sdata->u.mesh.user_mpm ||
551 	    sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
552 		if (mesh_peer_accepts_plinks(elems) &&
553 		    mesh_plink_availables(sdata)) {
554 			int sig = 0;
555 
556 			if (ieee80211_hw_check(&sdata->local->hw, SIGNAL_DBM))
557 				sig = rx_status->signal;
558 
559 			cfg80211_notify_new_peer_candidate(sdata->dev, addr,
560 							   elems->ie_start,
561 							   elems->total_len,
562 							   sig, GFP_KERNEL);
563 		}
564 	} else
565 		sta = __mesh_sta_info_alloc(sdata, addr);
566 
567 	return sta;
568 }
569 
570 /*
571  * mesh_sta_info_get - return mesh sta info entry for @addr.
572  *
573  * @sdata: local meshif
574  * @addr: peer's address
575  * @elems: IEs from beacon or mesh peering frame.
576  * @rx_status: rx status for the frame for signal reporting
577  *
578  * Return existing or newly allocated sta_info under RCU read lock.
579  * (re)initialize with given IEs.
580  */
581 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)582 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
583 		  u8 *addr, struct ieee802_11_elems *elems,
584 		  struct ieee80211_rx_status *rx_status) __acquires(RCU)
585 {
586 	struct sta_info *sta = NULL;
587 
588 	rcu_read_lock();
589 	sta = sta_info_get(sdata, addr);
590 	if (sta) {
591 		mesh_sta_info_init(sdata, sta, elems);
592 	} else {
593 		rcu_read_unlock();
594 		/* can't run atomic */
595 		sta = mesh_sta_info_alloc(sdata, addr, elems, rx_status);
596 		if (!sta) {
597 			rcu_read_lock();
598 			return NULL;
599 		}
600 
601 		mesh_sta_info_init(sdata, sta, elems);
602 
603 		if (sta_info_insert_rcu(sta))
604 			return NULL;
605 	}
606 
607 	return sta;
608 }
609 
610 /*
611  * mesh_neighbour_update - update or initialize new mesh neighbor.
612  *
613  * @sdata: local meshif
614  * @addr: peer's address
615  * @elems: IEs from beacon or mesh peering frame
616  * @rx_status: rx status for the frame for signal reporting
617  *
618  * Initiates peering if appropriate.
619  */
mesh_neighbour_update(struct ieee80211_sub_if_data * sdata,u8 * hw_addr,struct ieee802_11_elems * elems,struct ieee80211_rx_status * rx_status)620 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
621 			   u8 *hw_addr,
622 			   struct ieee802_11_elems *elems,
623 			   struct ieee80211_rx_status *rx_status)
624 {
625 	struct sta_info *sta;
626 	u64 changed = 0;
627 
628 	sta = mesh_sta_info_get(sdata, hw_addr, elems, rx_status);
629 	if (!sta)
630 		goto out;
631 
632 	sta->mesh->connected_to_gate = elems->mesh_config->meshconf_form &
633 		IEEE80211_MESHCONF_FORM_CONNECTED_TO_GATE;
634 
635 	if (mesh_peer_accepts_plinks(elems) &&
636 	    sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
637 	    sdata->u.mesh.accepting_plinks &&
638 	    sdata->u.mesh.mshcfg.auto_open_plinks &&
639 	    rssi_threshold_check(sdata, sta))
640 		changed = mesh_plink_open(sta);
641 
642 	ieee80211_mps_frame_release(sta, elems);
643 out:
644 	rcu_read_unlock();
645 	ieee80211_mbss_info_change_notify(sdata, changed);
646 }
647 
mesh_plink_timer(struct timer_list * t)648 void mesh_plink_timer(struct timer_list *t)
649 {
650 	struct mesh_sta *mesh = from_timer(mesh, t, plink_timer);
651 	struct sta_info *sta;
652 	u16 reason = 0;
653 	struct ieee80211_sub_if_data *sdata;
654 	struct mesh_config *mshcfg;
655 	enum ieee80211_self_protected_actioncode action = 0;
656 
657 	/*
658 	 * This STA is valid because sta_info_destroy() will
659 	 * del_timer_sync() this timer after having made sure
660 	 * it cannot be readded (by deleting the plink.)
661 	 */
662 	sta = mesh->plink_sta;
663 
664 	if (sta->sdata->local->quiescing)
665 		return;
666 
667 	spin_lock_bh(&sta->mesh->plink_lock);
668 
669 	/* If a timer fires just before a state transition on another CPU,
670 	 * we may have already extended the timeout and changed state by the
671 	 * time we've acquired the lock and arrived  here.  In that case,
672 	 * skip this timer and wait for the new one.
673 	 */
674 	if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
675 		mpl_dbg(sta->sdata,
676 			"Ignoring timer for %pM in state %s (timer adjusted)",
677 			sta->sta.addr, mplstates[sta->mesh->plink_state]);
678 		spin_unlock_bh(&sta->mesh->plink_lock);
679 		return;
680 	}
681 
682 	/* del_timer() and handler may race when entering these states */
683 	if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
684 	    sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
685 		mpl_dbg(sta->sdata,
686 			"Ignoring timer for %pM in state %s (timer deleted)",
687 			sta->sta.addr, mplstates[sta->mesh->plink_state]);
688 		spin_unlock_bh(&sta->mesh->plink_lock);
689 		return;
690 	}
691 
692 	mpl_dbg(sta->sdata,
693 		"Mesh plink timer for %pM fired on state %s\n",
694 		sta->sta.addr, mplstates[sta->mesh->plink_state]);
695 	sdata = sta->sdata;
696 	mshcfg = &sdata->u.mesh.mshcfg;
697 
698 	switch (sta->mesh->plink_state) {
699 	case NL80211_PLINK_OPN_RCVD:
700 	case NL80211_PLINK_OPN_SNT:
701 		/* retry timer */
702 		if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
703 			u32 rand;
704 			mpl_dbg(sta->sdata,
705 				"Mesh plink for %pM (retry, timeout): %d %d\n",
706 				sta->sta.addr, sta->mesh->plink_retries,
707 				sta->mesh->plink_timeout);
708 			get_random_bytes(&rand, sizeof(u32));
709 			sta->mesh->plink_timeout = sta->mesh->plink_timeout +
710 					     rand % sta->mesh->plink_timeout;
711 			++sta->mesh->plink_retries;
712 			mod_plink_timer(sta, sta->mesh->plink_timeout);
713 			action = WLAN_SP_MESH_PEERING_OPEN;
714 			break;
715 		}
716 		reason = WLAN_REASON_MESH_MAX_RETRIES;
717 		fallthrough;
718 	case NL80211_PLINK_CNF_RCVD:
719 		/* confirm timer */
720 		if (!reason)
721 			reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
722 		sta->mesh->plink_state = NL80211_PLINK_HOLDING;
723 		mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
724 		action = WLAN_SP_MESH_PEERING_CLOSE;
725 		break;
726 	case NL80211_PLINK_HOLDING:
727 		/* holding timer */
728 		del_timer(&sta->mesh->plink_timer);
729 		mesh_plink_fsm_restart(sta);
730 		break;
731 	default:
732 		break;
733 	}
734 	spin_unlock_bh(&sta->mesh->plink_lock);
735 	if (action)
736 		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
737 				    sta->mesh->llid, sta->mesh->plid, reason);
738 }
739 
mesh_plink_timer_set(struct sta_info * sta,u32 timeout)740 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
741 {
742 	sta->mesh->plink_timeout = timeout;
743 	mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
744 }
745 
llid_in_use(struct ieee80211_sub_if_data * sdata,u16 llid)746 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
747 			u16 llid)
748 {
749 	struct ieee80211_local *local = sdata->local;
750 	bool in_use = false;
751 	struct sta_info *sta;
752 
753 	rcu_read_lock();
754 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
755 		if (sdata != sta->sdata)
756 			continue;
757 
758 		if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
759 			in_use = true;
760 			break;
761 		}
762 	}
763 	rcu_read_unlock();
764 
765 	return in_use;
766 }
767 
mesh_get_new_llid(struct ieee80211_sub_if_data * sdata)768 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
769 {
770 	u16 llid;
771 
772 	do {
773 		get_random_bytes(&llid, sizeof(llid));
774 	} while (llid_in_use(sdata, llid));
775 
776 	return llid;
777 }
778 
mesh_plink_open(struct sta_info * sta)779 u64 mesh_plink_open(struct sta_info *sta)
780 {
781 	struct ieee80211_sub_if_data *sdata = sta->sdata;
782 	u64 changed;
783 
784 	if (!test_sta_flag(sta, WLAN_STA_AUTH))
785 		return 0;
786 
787 	spin_lock_bh(&sta->mesh->plink_lock);
788 	sta->mesh->llid = mesh_get_new_llid(sdata);
789 	if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
790 	    sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
791 		spin_unlock_bh(&sta->mesh->plink_lock);
792 		return 0;
793 	}
794 	sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
795 	mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
796 	spin_unlock_bh(&sta->mesh->plink_lock);
797 	mpl_dbg(sdata,
798 		"Mesh plink: starting establishment with %pM\n",
799 		sta->sta.addr);
800 
801 	/* set the non-peer mode to active during peering */
802 	changed = ieee80211_mps_local_status_update(sdata);
803 
804 	mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
805 			    sta->sta.addr, sta->mesh->llid, 0, 0);
806 	return changed;
807 }
808 
mesh_plink_block(struct sta_info * sta)809 u64 mesh_plink_block(struct sta_info *sta)
810 {
811 	u64 changed;
812 
813 	spin_lock_bh(&sta->mesh->plink_lock);
814 	changed = __mesh_plink_deactivate(sta);
815 	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
816 	spin_unlock_bh(&sta->mesh->plink_lock);
817 	mesh_path_flush_by_nexthop(sta);
818 
819 	return changed;
820 }
821 
mesh_plink_close(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum plink_event event)822 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
823 			     struct sta_info *sta,
824 			     enum plink_event event)
825 {
826 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
827 	u16 reason = (event == CLS_ACPT) ?
828 		     WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
829 
830 	sta->mesh->reason = reason;
831 	sta->mesh->plink_state = NL80211_PLINK_HOLDING;
832 	mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
833 }
834 
mesh_plink_establish(struct ieee80211_sub_if_data * sdata,struct sta_info * sta)835 static u64 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
836 				struct sta_info *sta)
837 {
838 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
839 	u64 changed = 0;
840 
841 	del_timer(&sta->mesh->plink_timer);
842 	sta->mesh->plink_state = NL80211_PLINK_ESTAB;
843 	changed |= mesh_plink_inc_estab_count(sdata);
844 	changed |= mesh_set_ht_prot_mode(sdata);
845 	changed |= mesh_set_short_slot_time(sdata);
846 	mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
847 	ieee80211_mps_sta_status_update(sta);
848 	changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
849 	return changed;
850 }
851 
852 /**
853  * mesh_plink_fsm - step @sta MPM based on @event
854  *
855  * @sdata: interface
856  * @sta: mesh neighbor
857  * @event: peering event
858  *
859  * Return: changed MBSS flags
860  */
mesh_plink_fsm(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum plink_event event)861 static u64 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
862 			  struct sta_info *sta, enum plink_event event)
863 {
864 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
865 	enum ieee80211_self_protected_actioncode action = 0;
866 	u64 changed = 0;
867 	bool flush = false;
868 
869 	mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
870 		mplstates[sta->mesh->plink_state], mplevents[event]);
871 
872 	spin_lock_bh(&sta->mesh->plink_lock);
873 	switch (sta->mesh->plink_state) {
874 	case NL80211_PLINK_LISTEN:
875 		switch (event) {
876 		case CLS_ACPT:
877 			mesh_plink_fsm_restart(sta);
878 			break;
879 		case OPN_ACPT:
880 			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
881 			sta->mesh->llid = mesh_get_new_llid(sdata);
882 			mesh_plink_timer_set(sta,
883 					     mshcfg->dot11MeshRetryTimeout);
884 
885 			/* set the non-peer mode to active during peering */
886 			changed |= ieee80211_mps_local_status_update(sdata);
887 			action = WLAN_SP_MESH_PEERING_OPEN;
888 			break;
889 		default:
890 			break;
891 		}
892 		break;
893 	case NL80211_PLINK_OPN_SNT:
894 		switch (event) {
895 		case OPN_RJCT:
896 		case CNF_RJCT:
897 		case CLS_ACPT:
898 			mesh_plink_close(sdata, sta, event);
899 			action = WLAN_SP_MESH_PEERING_CLOSE;
900 			break;
901 		case OPN_ACPT:
902 			/* retry timer is left untouched */
903 			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
904 			action = WLAN_SP_MESH_PEERING_CONFIRM;
905 			break;
906 		case CNF_ACPT:
907 			sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
908 			mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
909 			break;
910 		default:
911 			break;
912 		}
913 		break;
914 	case NL80211_PLINK_OPN_RCVD:
915 		switch (event) {
916 		case OPN_RJCT:
917 		case CNF_RJCT:
918 		case CLS_ACPT:
919 			mesh_plink_close(sdata, sta, event);
920 			action = WLAN_SP_MESH_PEERING_CLOSE;
921 			break;
922 		case OPN_ACPT:
923 			action = WLAN_SP_MESH_PEERING_CONFIRM;
924 			break;
925 		case CNF_ACPT:
926 			changed |= mesh_plink_establish(sdata, sta);
927 			break;
928 		default:
929 			break;
930 		}
931 		break;
932 	case NL80211_PLINK_CNF_RCVD:
933 		switch (event) {
934 		case OPN_RJCT:
935 		case CNF_RJCT:
936 		case CLS_ACPT:
937 			mesh_plink_close(sdata, sta, event);
938 			action = WLAN_SP_MESH_PEERING_CLOSE;
939 			break;
940 		case OPN_ACPT:
941 			changed |= mesh_plink_establish(sdata, sta);
942 			action = WLAN_SP_MESH_PEERING_CONFIRM;
943 			break;
944 		default:
945 			break;
946 		}
947 		break;
948 	case NL80211_PLINK_ESTAB:
949 		switch (event) {
950 		case CLS_ACPT:
951 			changed |= __mesh_plink_deactivate(sta);
952 			changed |= mesh_set_ht_prot_mode(sdata);
953 			changed |= mesh_set_short_slot_time(sdata);
954 			mesh_plink_close(sdata, sta, event);
955 			action = WLAN_SP_MESH_PEERING_CLOSE;
956 			flush = true;
957 			break;
958 		case OPN_ACPT:
959 			action = WLAN_SP_MESH_PEERING_CONFIRM;
960 			break;
961 		default:
962 			break;
963 		}
964 		break;
965 	case NL80211_PLINK_HOLDING:
966 		switch (event) {
967 		case CLS_ACPT:
968 			del_timer(&sta->mesh->plink_timer);
969 			mesh_plink_fsm_restart(sta);
970 			break;
971 		case OPN_ACPT:
972 		case CNF_ACPT:
973 		case OPN_RJCT:
974 		case CNF_RJCT:
975 			action = WLAN_SP_MESH_PEERING_CLOSE;
976 			break;
977 		default:
978 			break;
979 		}
980 		break;
981 	default:
982 		/* should not get here, PLINK_BLOCKED is dealt with at the
983 		 * beginning of the function
984 		 */
985 		break;
986 	}
987 	spin_unlock_bh(&sta->mesh->plink_lock);
988 	if (flush)
989 		mesh_path_flush_by_nexthop(sta);
990 	if (action) {
991 		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
992 				    sta->mesh->llid, sta->mesh->plid,
993 				    sta->mesh->reason);
994 
995 		/* also send confirm in open case */
996 		if (action == WLAN_SP_MESH_PEERING_OPEN) {
997 			mesh_plink_frame_tx(sdata, sta,
998 					    WLAN_SP_MESH_PEERING_CONFIRM,
999 					    sta->sta.addr, sta->mesh->llid,
1000 					    sta->mesh->plid, 0);
1001 		}
1002 	}
1003 
1004 	return changed;
1005 }
1006 
1007 /*
1008  * mesh_plink_get_event - get correct MPM event
1009  *
1010  * @sdata: interface
1011  * @sta: peer, leave NULL if processing a frame from a new suitable peer
1012  * @elems: peering management IEs
1013  * @ftype: frame type
1014  * @llid: peer's peer link ID
1015  * @plid: peer's local link ID
1016  *
1017  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
1018  * an error.
1019  */
1020 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)1021 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
1022 		     struct sta_info *sta,
1023 		     struct ieee802_11_elems *elems,
1024 		     enum ieee80211_self_protected_actioncode ftype,
1025 		     u16 llid, u16 plid)
1026 {
1027 	enum plink_event event = PLINK_UNDEFINED;
1028 	u8 ie_len = elems->peering_len;
1029 	bool matches_local;
1030 
1031 	matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
1032 			 mesh_matches_local(sdata, elems));
1033 
1034 	/* deny open request from non-matching peer */
1035 	if (!matches_local && !sta) {
1036 		event = OPN_RJCT;
1037 		goto out;
1038 	}
1039 
1040 	if (!sta) {
1041 		if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
1042 			mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
1043 			goto out;
1044 		}
1045 		/* ftype == WLAN_SP_MESH_PEERING_OPEN */
1046 		if (!mesh_plink_free_count(sdata)) {
1047 			mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
1048 			goto out;
1049 		}
1050 
1051 		/* new matching peer */
1052 		event = OPN_ACPT;
1053 		goto out;
1054 	} else {
1055 		if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
1056 			mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
1057 			goto out;
1058 		}
1059 		if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
1060 			goto out;
1061 	}
1062 
1063 	switch (ftype) {
1064 	case WLAN_SP_MESH_PEERING_OPEN:
1065 		if (!matches_local)
1066 			event = OPN_RJCT;
1067 		else if (!mesh_plink_free_count(sdata) ||
1068 			 (sta->mesh->plid && sta->mesh->plid != plid))
1069 			event = OPN_IGNR;
1070 		else
1071 			event = OPN_ACPT;
1072 		break;
1073 	case WLAN_SP_MESH_PEERING_CONFIRM:
1074 		if (!matches_local)
1075 			event = CNF_RJCT;
1076 		else if (!mesh_plink_free_count(sdata) ||
1077 			 sta->mesh->llid != llid ||
1078 			 (sta->mesh->plid && sta->mesh->plid != plid))
1079 			event = CNF_IGNR;
1080 		else
1081 			event = CNF_ACPT;
1082 		break;
1083 	case WLAN_SP_MESH_PEERING_CLOSE:
1084 		if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1085 			/* Do not check for llid or plid. This does not
1086 			 * follow the standard but since multiple plinks
1087 			 * per sta are not supported, it is necessary in
1088 			 * order to avoid a livelock when MP A sees an
1089 			 * establish peer link to MP B but MP B does not
1090 			 * see it. This can be caused by a timeout in
1091 			 * B's peer link establishment or B beign
1092 			 * restarted.
1093 			 */
1094 			event = CLS_ACPT;
1095 		else if (sta->mesh->plid != plid)
1096 			event = CLS_IGNR;
1097 		else if (ie_len == 8 && sta->mesh->llid != llid)
1098 			event = CLS_IGNR;
1099 		else
1100 			event = CLS_ACPT;
1101 		break;
1102 	default:
1103 		mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1104 		break;
1105 	}
1106 
1107 out:
1108 	return event;
1109 }
1110 
1111 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)1112 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1113 			 struct ieee80211_mgmt *mgmt,
1114 			 struct ieee802_11_elems *elems,
1115 			 struct ieee80211_rx_status *rx_status)
1116 {
1117 
1118 	struct sta_info *sta;
1119 	enum plink_event event;
1120 	enum ieee80211_self_protected_actioncode ftype;
1121 	u64 changed = 0;
1122 	u8 ie_len = elems->peering_len;
1123 	u16 plid, llid = 0;
1124 
1125 	if (!elems->peering) {
1126 		mpl_dbg(sdata,
1127 			"Mesh plink: missing necessary peer link ie\n");
1128 		return;
1129 	}
1130 
1131 	if (elems->rsn_len &&
1132 	    sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1133 		mpl_dbg(sdata,
1134 			"Mesh plink: can't establish link with secure peer\n");
1135 		return;
1136 	}
1137 
1138 	ftype = mgmt->u.action.u.self_prot.action_code;
1139 	if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1140 	    (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1141 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1142 							&& ie_len != 8)) {
1143 		mpl_dbg(sdata,
1144 			"Mesh plink: incorrect plink ie length %d %d\n",
1145 			ftype, ie_len);
1146 		return;
1147 	}
1148 
1149 	if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1150 	    (!elems->mesh_id || !elems->mesh_config)) {
1151 		mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1152 		return;
1153 	}
1154 	/* Note the lines below are correct, the llid in the frame is the plid
1155 	 * from the point of view of this host.
1156 	 */
1157 	plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1158 	if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1159 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1160 		llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1161 
1162 	/* WARNING: Only for sta pointer, is dropped & re-acquired */
1163 	rcu_read_lock();
1164 
1165 	sta = sta_info_get(sdata, mgmt->sa);
1166 
1167 	if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1168 	    !rssi_threshold_check(sdata, sta)) {
1169 		mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1170 			mgmt->sa);
1171 		goto unlock_rcu;
1172 	}
1173 
1174 	/* Now we will figure out the appropriate event... */
1175 	event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1176 
1177 	if (event == OPN_ACPT) {
1178 		rcu_read_unlock();
1179 		/* allocate sta entry if necessary and update info */
1180 		sta = mesh_sta_info_get(sdata, mgmt->sa, elems, rx_status);
1181 		if (!sta) {
1182 			mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1183 			goto unlock_rcu;
1184 		}
1185 		sta->mesh->plid = plid;
1186 	} else if (!sta && event == OPN_RJCT) {
1187 		mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1188 				    mgmt->sa, 0, plid,
1189 				    WLAN_REASON_MESH_CONFIG);
1190 		goto unlock_rcu;
1191 	} else if (!sta || event == PLINK_UNDEFINED) {
1192 		/* something went wrong */
1193 		goto unlock_rcu;
1194 	}
1195 
1196 	if (event == CNF_ACPT) {
1197 		/* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1198 		if (!sta->mesh->plid)
1199 			sta->mesh->plid = plid;
1200 
1201 		sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1202 	}
1203 
1204 	changed |= mesh_plink_fsm(sdata, sta, event);
1205 
1206 unlock_rcu:
1207 	rcu_read_unlock();
1208 
1209 	if (changed)
1210 		ieee80211_mbss_info_change_notify(sdata, changed);
1211 }
1212 
mesh_rx_plink_frame(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,size_t len,struct ieee80211_rx_status * rx_status)1213 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1214 			 struct ieee80211_mgmt *mgmt, size_t len,
1215 			 struct ieee80211_rx_status *rx_status)
1216 {
1217 	struct ieee802_11_elems *elems;
1218 	size_t baselen;
1219 	u8 *baseaddr;
1220 
1221 	/* need action_code, aux */
1222 	if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1223 		return;
1224 
1225 	if (sdata->u.mesh.user_mpm)
1226 		/* userspace must register for these */
1227 		return;
1228 
1229 	if (is_multicast_ether_addr(mgmt->da)) {
1230 		mpl_dbg(sdata,
1231 			"Mesh plink: ignore frame from multicast address\n");
1232 		return;
1233 	}
1234 
1235 	baseaddr = mgmt->u.action.u.self_prot.variable;
1236 	baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1237 	if (mgmt->u.action.u.self_prot.action_code ==
1238 						WLAN_SP_MESH_PEERING_CONFIRM) {
1239 		baseaddr += 4;
1240 		baselen += 4;
1241 
1242 		if (baselen > len)
1243 			return;
1244 	}
1245 	elems = ieee802_11_parse_elems(baseaddr, len - baselen, true, NULL);
1246 	if (elems) {
1247 		mesh_process_plink_frame(sdata, mgmt, elems, rx_status);
1248 		kfree(elems);
1249 	}
1250 }
1251