xref: /linux/net/mac80211/mesh_plink.c (revision be54f8c558027a218423134dd9b8c7c46d92204a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2008, 2009 open80211s Ltd.
4  * Copyright (C) 2019, 2021-2024 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  *
157  * Returns: BSS_CHANGED_HT or 0 for no change
158  */
mesh_set_ht_prot_mode(struct ieee80211_sub_if_data * sdata)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.chanreq.oper.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.chanreq.oper.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 
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)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 	ie_len_eht_cap = ieee80211_ie_len_eht_cap(sdata);
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 		u32 basic_rates;
268 
269 		sband = ieee80211_get_sband(sdata);
270 		if (!sband) {
271 			err = -EINVAL;
272 			goto free;
273 		}
274 
275 		/* capability info */
276 		pos = skb_put_zero(skb, 2);
277 		if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
278 			/* AID */
279 			pos = skb_put(skb, 2);
280 			put_unaligned_le16(sta->sta.aid, pos);
281 		}
282 
283 		basic_rates = sdata->vif.bss_conf.basic_rates;
284 
285 		if (ieee80211_put_srates_elem(skb, sband, basic_rates,
286 					      0, WLAN_EID_SUPP_RATES) ||
287 		    ieee80211_put_srates_elem(skb, sband, basic_rates,
288 					      0, WLAN_EID_EXT_SUPP_RATES) ||
289 		    mesh_add_rsn_ie(sdata, skb) ||
290 		    mesh_add_meshid_ie(sdata, skb) ||
291 		    mesh_add_meshconf_ie(sdata, skb))
292 			goto free;
293 	} else {	/* WLAN_SP_MESH_PEERING_CLOSE */
294 		info->flags |= IEEE80211_TX_CTL_NO_ACK;
295 		if (mesh_add_meshid_ie(sdata, skb))
296 			goto free;
297 	}
298 
299 	/* Add Mesh Peering Management element */
300 	switch (action) {
301 	case WLAN_SP_MESH_PEERING_OPEN:
302 		break;
303 	case WLAN_SP_MESH_PEERING_CONFIRM:
304 		ie_len += 2;
305 		include_plid = true;
306 		break;
307 	case WLAN_SP_MESH_PEERING_CLOSE:
308 		if (plid) {
309 			ie_len += 2;
310 			include_plid = true;
311 		}
312 		ie_len += 2;	/* reason code */
313 		break;
314 	default:
315 		err = -EINVAL;
316 		goto free;
317 	}
318 
319 	if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
320 		goto free;
321 
322 	pos = skb_put(skb, 2 + ie_len);
323 	*pos++ = WLAN_EID_PEER_MGMT;
324 	*pos++ = ie_len;
325 	memcpy(pos, &peering_proto, 2);
326 	pos += 2;
327 	put_unaligned_le16(llid, pos);
328 	pos += 2;
329 	if (include_plid) {
330 		put_unaligned_le16(plid, pos);
331 		pos += 2;
332 	}
333 	if (action == WLAN_SP_MESH_PEERING_CLOSE) {
334 		put_unaligned_le16(reason, pos);
335 		pos += 2;
336 	}
337 
338 	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
339 		if (mesh_add_ht_cap_ie(sdata, skb) ||
340 		    mesh_add_ht_oper_ie(sdata, skb) ||
341 		    mesh_add_vht_cap_ie(sdata, skb) ||
342 		    mesh_add_vht_oper_ie(sdata, skb) ||
343 		    mesh_add_he_cap_ie(sdata, skb, ie_len_he_cap) ||
344 		    mesh_add_he_oper_ie(sdata, skb) ||
345 		    mesh_add_he_6ghz_cap_ie(sdata, skb) ||
346 		    mesh_add_eht_cap_ie(sdata, skb, ie_len_eht_cap) ||
347 		    mesh_add_eht_oper_ie(sdata, skb))
348 			goto free;
349 	}
350 
351 	if (mesh_add_vendor_ies(sdata, skb))
352 		goto free;
353 
354 	ieee80211_tx_skb(sdata, skb);
355 	return 0;
356 free:
357 	kfree_skb(skb);
358 	return err;
359 }
360 
361 /**
362  * __mesh_plink_deactivate - deactivate mesh peer link
363  *
364  * @sta: mesh peer link to deactivate
365  *
366  * Mesh paths with this peer as next hop should be flushed
367  * by the caller outside of plink_lock.
368  *
369  * Returns: beacon changed flag if the beacon content changed.
370  *
371  * Locking: the caller must hold sta->mesh->plink_lock
372  */
__mesh_plink_deactivate(struct sta_info * sta)373 static u64 __mesh_plink_deactivate(struct sta_info *sta)
374 {
375 	struct ieee80211_sub_if_data *sdata = sta->sdata;
376 	u64 changed = 0;
377 
378 	lockdep_assert_held(&sta->mesh->plink_lock);
379 
380 	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
381 		changed = mesh_plink_dec_estab_count(sdata);
382 	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
383 
384 	ieee80211_mps_sta_status_update(sta);
385 	changed |= ieee80211_mps_set_sta_local_pm(sta,
386 			NL80211_MESH_POWER_UNKNOWN);
387 
388 	return changed;
389 }
390 
391 /**
392  * mesh_plink_deactivate - deactivate mesh peer link
393  *
394  * @sta: mesh peer link to deactivate
395  *
396  * All mesh paths with this peer as next hop will be flushed
397  *
398  * Returns: beacon changed flag if the beacon content changed.
399  */
mesh_plink_deactivate(struct sta_info * sta)400 u64 mesh_plink_deactivate(struct sta_info *sta)
401 {
402 	struct ieee80211_sub_if_data *sdata = sta->sdata;
403 	u64 changed;
404 
405 	spin_lock_bh(&sta->mesh->plink_lock);
406 	changed = __mesh_plink_deactivate(sta);
407 
408 	if (!sdata->u.mesh.user_mpm) {
409 		sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
410 		mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
411 				    sta->sta.addr, sta->mesh->llid,
412 				    sta->mesh->plid, sta->mesh->reason);
413 	}
414 	spin_unlock_bh(&sta->mesh->plink_lock);
415 	if (!sdata->u.mesh.user_mpm)
416 		timer_delete_sync(&sta->mesh->plink_timer);
417 	mesh_path_flush_by_nexthop(sta);
418 
419 	/* make sure no readers can access nexthop sta from here on */
420 	synchronize_net();
421 
422 	return changed;
423 }
424 
mesh_sta_info_init(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,struct ieee802_11_elems * elems)425 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
426 			       struct sta_info *sta,
427 			       struct ieee802_11_elems *elems)
428 {
429 	struct ieee80211_local *local = sdata->local;
430 	struct ieee80211_supported_band *sband;
431 	u32 rates, changed = 0;
432 	enum ieee80211_sta_rx_bandwidth bw = sta->sta.deflink.bandwidth;
433 
434 	sband = ieee80211_get_sband(sdata);
435 	if (!sband)
436 		return;
437 
438 	rates = ieee80211_sta_get_rates(sdata, elems, sband->band, NULL);
439 
440 	spin_lock_bh(&sta->mesh->plink_lock);
441 	sta->deflink.rx_stats.last_rx = jiffies;
442 
443 	/* rates and capabilities don't change during peering */
444 	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
445 	    sta->mesh->processed_beacon)
446 		goto out;
447 	sta->mesh->processed_beacon = true;
448 
449 	if (sta->sta.deflink.supp_rates[sband->band] != rates)
450 		changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
451 	sta->sta.deflink.supp_rates[sband->band] = rates;
452 
453 	if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
454 					      elems->ht_cap_elem,
455 					      &sta->deflink))
456 		changed |= IEEE80211_RC_BW_CHANGED;
457 
458 	ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
459 					    elems->vht_cap_elem, NULL,
460 					    &sta->deflink);
461 
462 	ieee80211_he_cap_ie_to_sta_he_cap(sdata, sband, elems->he_cap,
463 					  elems->he_cap_len,
464 					  elems->he_6ghz_capa,
465 					  &sta->deflink);
466 
467 	ieee80211_eht_cap_ie_to_sta_eht_cap(sdata, sband, elems->he_cap,
468 					    elems->he_cap_len,
469 					    elems->eht_cap, elems->eht_cap_len,
470 					    &sta->deflink);
471 
472 	if (bw != sta->sta.deflink.bandwidth)
473 		changed |= IEEE80211_RC_BW_CHANGED;
474 
475 	/* HT peer is operating 20MHz-only */
476 	if (elems->ht_operation &&
477 	    !(elems->ht_operation->ht_param &
478 	      IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
479 		if (sta->sta.deflink.bandwidth != IEEE80211_STA_RX_BW_20)
480 			changed |= IEEE80211_RC_BW_CHANGED;
481 		sta->sta.deflink.bandwidth = IEEE80211_STA_RX_BW_20;
482 	}
483 
484 	/* FIXME: this check is wrong without SW rate control */
485 	if (!test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
486 		rate_control_rate_init(&sta->deflink);
487 	else
488 		rate_control_rate_update(local, sband, &sta->deflink, changed);
489 out:
490 	spin_unlock_bh(&sta->mesh->plink_lock);
491 }
492 
mesh_allocate_aid(struct ieee80211_sub_if_data * sdata)493 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
494 {
495 	struct sta_info *sta;
496 	unsigned long *aid_map;
497 	int aid;
498 
499 	aid_map = bitmap_zalloc(IEEE80211_MAX_AID + 1, GFP_KERNEL);
500 	if (!aid_map)
501 		return -ENOMEM;
502 
503 	/* reserve aid 0 for mcast indication */
504 	__set_bit(0, aid_map);
505 
506 	rcu_read_lock();
507 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
508 		__set_bit(sta->sta.aid, aid_map);
509 	rcu_read_unlock();
510 
511 	aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
512 	bitmap_free(aid_map);
513 
514 	if (aid > IEEE80211_MAX_AID)
515 		return -ENOBUFS;
516 
517 	return aid;
518 }
519 
520 static struct sta_info *
__mesh_sta_info_alloc(struct ieee80211_sub_if_data * sdata,u8 * hw_addr)521 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
522 {
523 	struct sta_info *sta;
524 	int aid;
525 
526 	if (sdata->local->num_sta >= MESH_MAX_PLINKS)
527 		return NULL;
528 
529 	aid = mesh_allocate_aid(sdata);
530 	if (aid < 0)
531 		return NULL;
532 
533 	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
534 	if (!sta)
535 		return NULL;
536 
537 	sta->mesh->plink_state = NL80211_PLINK_LISTEN;
538 	sta->sta.wme = true;
539 	sta->sta.aid = aid;
540 
541 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
542 	sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
543 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
544 
545 	return sta;
546 }
547 
548 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)549 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
550 		    struct ieee802_11_elems *elems,
551 		    struct ieee80211_rx_status *rx_status)
552 {
553 	struct sta_info *sta = NULL;
554 
555 	/* Userspace handles station allocation */
556 	if (sdata->u.mesh.user_mpm ||
557 	    sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
558 		if (mesh_peer_accepts_plinks(elems) &&
559 		    mesh_plink_availables(sdata)) {
560 			int sig = 0;
561 
562 			if (ieee80211_hw_check(&sdata->local->hw, SIGNAL_DBM))
563 				sig = rx_status->signal;
564 
565 			cfg80211_notify_new_peer_candidate(sdata->dev, addr,
566 							   elems->ie_start,
567 							   elems->total_len,
568 							   sig, GFP_KERNEL);
569 		}
570 	} else
571 		sta = __mesh_sta_info_alloc(sdata, addr);
572 
573 	return sta;
574 }
575 
576 /*
577  * mesh_sta_info_get - return mesh sta info entry for @addr.
578  *
579  * @sdata: local meshif
580  * @addr: peer's address
581  * @elems: IEs from beacon or mesh peering frame.
582  * @rx_status: rx status for the frame for signal reporting
583  *
584  * Return existing or newly allocated sta_info under RCU read lock.
585  * (re)initialize with given IEs.
586  */
587 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)588 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
589 		  u8 *addr, struct ieee802_11_elems *elems,
590 		  struct ieee80211_rx_status *rx_status) __acquires(RCU)
591 {
592 	struct sta_info *sta = NULL;
593 
594 	rcu_read_lock();
595 	sta = sta_info_get(sdata, addr);
596 	if (sta) {
597 		mesh_sta_info_init(sdata, sta, elems);
598 	} else {
599 		rcu_read_unlock();
600 		/* can't run atomic */
601 		sta = mesh_sta_info_alloc(sdata, addr, elems, rx_status);
602 		if (!sta) {
603 			rcu_read_lock();
604 			return NULL;
605 		}
606 
607 		mesh_sta_info_init(sdata, sta, elems);
608 
609 		if (sta_info_insert_rcu(sta))
610 			return NULL;
611 	}
612 
613 	return sta;
614 }
615 
616 /*
617  * mesh_neighbour_update - update or initialize new mesh neighbor.
618  *
619  * @sdata: local meshif
620  * @addr: peer's address
621  * @elems: IEs from beacon or mesh peering frame
622  * @rx_status: rx status for the frame for signal reporting
623  *
624  * Initiates peering if appropriate.
625  */
mesh_neighbour_update(struct ieee80211_sub_if_data * sdata,u8 * hw_addr,struct ieee802_11_elems * elems,struct ieee80211_rx_status * rx_status)626 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
627 			   u8 *hw_addr,
628 			   struct ieee802_11_elems *elems,
629 			   struct ieee80211_rx_status *rx_status)
630 {
631 	struct sta_info *sta;
632 	u64 changed = 0;
633 
634 	sta = mesh_sta_info_get(sdata, hw_addr, elems, rx_status);
635 	if (!sta)
636 		goto out;
637 
638 	sta->mesh->connected_to_gate = elems->mesh_config->meshconf_form &
639 		IEEE80211_MESHCONF_FORM_CONNECTED_TO_GATE;
640 
641 	if (mesh_peer_accepts_plinks(elems) &&
642 	    sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
643 	    sdata->u.mesh.accepting_plinks &&
644 	    sdata->u.mesh.mshcfg.auto_open_plinks &&
645 	    rssi_threshold_check(sdata, sta))
646 		changed = mesh_plink_open(sta);
647 
648 	ieee80211_mps_frame_release(sta, elems);
649 out:
650 	rcu_read_unlock();
651 	ieee80211_mbss_info_change_notify(sdata, changed);
652 }
653 
mesh_plink_timer(struct timer_list * t)654 void mesh_plink_timer(struct timer_list *t)
655 {
656 	struct mesh_sta *mesh = timer_container_of(mesh, t, plink_timer);
657 	struct sta_info *sta;
658 	u16 reason = 0;
659 	struct ieee80211_sub_if_data *sdata;
660 	struct mesh_config *mshcfg;
661 	enum ieee80211_self_protected_actioncode action = 0;
662 
663 	/*
664 	 * This STA is valid because sta_info_destroy() will
665 	 * timer_delete_sync() this timer after having made sure
666 	 * it cannot be re-added (by deleting the plink.)
667 	 */
668 	sta = mesh->plink_sta;
669 
670 	if (sta->sdata->local->quiescing)
671 		return;
672 
673 	spin_lock_bh(&sta->mesh->plink_lock);
674 
675 	/* If a timer fires just before a state transition on another CPU,
676 	 * we may have already extended the timeout and changed state by the
677 	 * time we've acquired the lock and arrived  here.  In that case,
678 	 * skip this timer and wait for the new one.
679 	 */
680 	if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
681 		mpl_dbg(sta->sdata,
682 			"Ignoring timer for %pM in state %s (timer adjusted)",
683 			sta->sta.addr, mplstates[sta->mesh->plink_state]);
684 		spin_unlock_bh(&sta->mesh->plink_lock);
685 		return;
686 	}
687 
688 	/* timer_delete() and handler may race when entering these states */
689 	if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
690 	    sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
691 		mpl_dbg(sta->sdata,
692 			"Ignoring timer for %pM in state %s (timer deleted)",
693 			sta->sta.addr, mplstates[sta->mesh->plink_state]);
694 		spin_unlock_bh(&sta->mesh->plink_lock);
695 		return;
696 	}
697 
698 	mpl_dbg(sta->sdata,
699 		"Mesh plink timer for %pM fired on state %s\n",
700 		sta->sta.addr, mplstates[sta->mesh->plink_state]);
701 	sdata = sta->sdata;
702 	mshcfg = &sdata->u.mesh.mshcfg;
703 
704 	switch (sta->mesh->plink_state) {
705 	case NL80211_PLINK_OPN_RCVD:
706 	case NL80211_PLINK_OPN_SNT:
707 		/* retry timer */
708 		if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
709 			u32 rand;
710 			mpl_dbg(sta->sdata,
711 				"Mesh plink for %pM (retry, timeout): %d %d\n",
712 				sta->sta.addr, sta->mesh->plink_retries,
713 				sta->mesh->plink_timeout);
714 			get_random_bytes(&rand, sizeof(u32));
715 			sta->mesh->plink_timeout = sta->mesh->plink_timeout +
716 					     rand % sta->mesh->plink_timeout;
717 			++sta->mesh->plink_retries;
718 			mod_plink_timer(sta, sta->mesh->plink_timeout);
719 			action = WLAN_SP_MESH_PEERING_OPEN;
720 			break;
721 		}
722 		reason = WLAN_REASON_MESH_MAX_RETRIES;
723 		fallthrough;
724 	case NL80211_PLINK_CNF_RCVD:
725 		/* confirm timer */
726 		if (!reason)
727 			reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
728 		sta->mesh->plink_state = NL80211_PLINK_HOLDING;
729 		mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
730 		action = WLAN_SP_MESH_PEERING_CLOSE;
731 		break;
732 	case NL80211_PLINK_HOLDING:
733 		/* holding timer */
734 		timer_delete(&sta->mesh->plink_timer);
735 		mesh_plink_fsm_restart(sta);
736 		break;
737 	default:
738 		break;
739 	}
740 	spin_unlock_bh(&sta->mesh->plink_lock);
741 	if (action)
742 		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
743 				    sta->mesh->llid, sta->mesh->plid, reason);
744 }
745 
mesh_plink_timer_set(struct sta_info * sta,u32 timeout)746 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
747 {
748 	sta->mesh->plink_timeout = timeout;
749 	mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
750 }
751 
llid_in_use(struct ieee80211_sub_if_data * sdata,u16 llid)752 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
753 			u16 llid)
754 {
755 	struct ieee80211_local *local = sdata->local;
756 	bool in_use = false;
757 	struct sta_info *sta;
758 
759 	rcu_read_lock();
760 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
761 		if (sdata != sta->sdata)
762 			continue;
763 
764 		if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
765 			in_use = true;
766 			break;
767 		}
768 	}
769 	rcu_read_unlock();
770 
771 	return in_use;
772 }
773 
mesh_get_new_llid(struct ieee80211_sub_if_data * sdata)774 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
775 {
776 	u16 llid;
777 
778 	do {
779 		get_random_bytes(&llid, sizeof(llid));
780 	} while (llid_in_use(sdata, llid));
781 
782 	return llid;
783 }
784 
mesh_plink_open(struct sta_info * sta)785 u64 mesh_plink_open(struct sta_info *sta)
786 {
787 	struct ieee80211_sub_if_data *sdata = sta->sdata;
788 	u64 changed;
789 
790 	if (!test_sta_flag(sta, WLAN_STA_AUTH))
791 		return 0;
792 
793 	spin_lock_bh(&sta->mesh->plink_lock);
794 	sta->mesh->llid = mesh_get_new_llid(sdata);
795 	if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
796 	    sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
797 		spin_unlock_bh(&sta->mesh->plink_lock);
798 		return 0;
799 	}
800 	sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
801 	mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
802 	spin_unlock_bh(&sta->mesh->plink_lock);
803 	mpl_dbg(sdata,
804 		"Mesh plink: starting establishment with %pM\n",
805 		sta->sta.addr);
806 
807 	/* set the non-peer mode to active during peering */
808 	changed = ieee80211_mps_local_status_update(sdata);
809 
810 	mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
811 			    sta->sta.addr, sta->mesh->llid, 0, 0);
812 	return changed;
813 }
814 
mesh_plink_block(struct sta_info * sta)815 u64 mesh_plink_block(struct sta_info *sta)
816 {
817 	u64 changed;
818 
819 	spin_lock_bh(&sta->mesh->plink_lock);
820 	changed = __mesh_plink_deactivate(sta);
821 	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
822 	spin_unlock_bh(&sta->mesh->plink_lock);
823 	mesh_path_flush_by_nexthop(sta);
824 
825 	return changed;
826 }
827 
mesh_plink_close(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum plink_event event)828 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
829 			     struct sta_info *sta,
830 			     enum plink_event event)
831 {
832 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
833 	u16 reason = (event == CLS_ACPT) ?
834 		     WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
835 
836 	sta->mesh->reason = reason;
837 	sta->mesh->plink_state = NL80211_PLINK_HOLDING;
838 	mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
839 }
840 
mesh_plink_establish(struct ieee80211_sub_if_data * sdata,struct sta_info * sta)841 static u64 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
842 				struct sta_info *sta)
843 {
844 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
845 	u64 changed = 0;
846 
847 	timer_delete(&sta->mesh->plink_timer);
848 	sta->mesh->plink_state = NL80211_PLINK_ESTAB;
849 	changed |= mesh_plink_inc_estab_count(sdata);
850 	changed |= mesh_set_ht_prot_mode(sdata);
851 	changed |= mesh_set_short_slot_time(sdata);
852 	mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
853 	ieee80211_mps_sta_status_update(sta);
854 	changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
855 	return changed;
856 }
857 
858 /**
859  * mesh_plink_fsm - step @sta MPM based on @event
860  *
861  * @sdata: interface
862  * @sta: mesh neighbor
863  * @event: peering event
864  *
865  * Return: changed MBSS flags
866  */
mesh_plink_fsm(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum plink_event event)867 static u64 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
868 			  struct sta_info *sta, enum plink_event event)
869 {
870 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
871 	enum ieee80211_self_protected_actioncode action = 0;
872 	u64 changed = 0;
873 	bool flush = false;
874 
875 	mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
876 		mplstates[sta->mesh->plink_state], mplevents[event]);
877 
878 	spin_lock_bh(&sta->mesh->plink_lock);
879 	switch (sta->mesh->plink_state) {
880 	case NL80211_PLINK_LISTEN:
881 		switch (event) {
882 		case CLS_ACPT:
883 			mesh_plink_fsm_restart(sta);
884 			break;
885 		case OPN_ACPT:
886 			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
887 			sta->mesh->llid = mesh_get_new_llid(sdata);
888 			mesh_plink_timer_set(sta,
889 					     mshcfg->dot11MeshRetryTimeout);
890 
891 			/* set the non-peer mode to active during peering */
892 			changed |= ieee80211_mps_local_status_update(sdata);
893 			action = WLAN_SP_MESH_PEERING_OPEN;
894 			break;
895 		default:
896 			break;
897 		}
898 		break;
899 	case NL80211_PLINK_OPN_SNT:
900 		switch (event) {
901 		case OPN_RJCT:
902 		case CNF_RJCT:
903 		case CLS_ACPT:
904 			mesh_plink_close(sdata, sta, event);
905 			action = WLAN_SP_MESH_PEERING_CLOSE;
906 			break;
907 		case OPN_ACPT:
908 			/* retry timer is left untouched */
909 			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
910 			action = WLAN_SP_MESH_PEERING_CONFIRM;
911 			break;
912 		case CNF_ACPT:
913 			sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
914 			mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
915 			break;
916 		default:
917 			break;
918 		}
919 		break;
920 	case NL80211_PLINK_OPN_RCVD:
921 		switch (event) {
922 		case OPN_RJCT:
923 		case CNF_RJCT:
924 		case CLS_ACPT:
925 			mesh_plink_close(sdata, sta, event);
926 			action = WLAN_SP_MESH_PEERING_CLOSE;
927 			break;
928 		case OPN_ACPT:
929 			action = WLAN_SP_MESH_PEERING_CONFIRM;
930 			break;
931 		case CNF_ACPT:
932 			changed |= mesh_plink_establish(sdata, sta);
933 			break;
934 		default:
935 			break;
936 		}
937 		break;
938 	case NL80211_PLINK_CNF_RCVD:
939 		switch (event) {
940 		case OPN_RJCT:
941 		case CNF_RJCT:
942 		case CLS_ACPT:
943 			mesh_plink_close(sdata, sta, event);
944 			action = WLAN_SP_MESH_PEERING_CLOSE;
945 			break;
946 		case OPN_ACPT:
947 			changed |= mesh_plink_establish(sdata, sta);
948 			action = WLAN_SP_MESH_PEERING_CONFIRM;
949 			break;
950 		default:
951 			break;
952 		}
953 		break;
954 	case NL80211_PLINK_ESTAB:
955 		switch (event) {
956 		case CLS_ACPT:
957 			changed |= __mesh_plink_deactivate(sta);
958 			changed |= mesh_set_ht_prot_mode(sdata);
959 			changed |= mesh_set_short_slot_time(sdata);
960 			mesh_plink_close(sdata, sta, event);
961 			action = WLAN_SP_MESH_PEERING_CLOSE;
962 			flush = true;
963 			break;
964 		case OPN_ACPT:
965 			action = WLAN_SP_MESH_PEERING_CONFIRM;
966 			break;
967 		default:
968 			break;
969 		}
970 		break;
971 	case NL80211_PLINK_HOLDING:
972 		switch (event) {
973 		case CLS_ACPT:
974 			timer_delete(&sta->mesh->plink_timer);
975 			mesh_plink_fsm_restart(sta);
976 			break;
977 		case OPN_ACPT:
978 		case CNF_ACPT:
979 		case OPN_RJCT:
980 		case CNF_RJCT:
981 			action = WLAN_SP_MESH_PEERING_CLOSE;
982 			break;
983 		default:
984 			break;
985 		}
986 		break;
987 	default:
988 		/* should not get here, PLINK_BLOCKED is dealt with at the
989 		 * beginning of the function
990 		 */
991 		break;
992 	}
993 	spin_unlock_bh(&sta->mesh->plink_lock);
994 	if (flush)
995 		mesh_path_flush_by_nexthop(sta);
996 	if (action) {
997 		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
998 				    sta->mesh->llid, sta->mesh->plid,
999 				    sta->mesh->reason);
1000 
1001 		/* also send confirm in open case */
1002 		if (action == WLAN_SP_MESH_PEERING_OPEN) {
1003 			mesh_plink_frame_tx(sdata, sta,
1004 					    WLAN_SP_MESH_PEERING_CONFIRM,
1005 					    sta->sta.addr, sta->mesh->llid,
1006 					    sta->mesh->plid, 0);
1007 		}
1008 	}
1009 
1010 	return changed;
1011 }
1012 
1013 /*
1014  * mesh_plink_get_event - get correct MPM event
1015  *
1016  * @sdata: interface
1017  * @sta: peer, leave NULL if processing a frame from a new suitable peer
1018  * @elems: peering management IEs
1019  * @ftype: frame type
1020  * @llid: peer's peer link ID
1021  * @plid: peer's local link ID
1022  *
1023  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
1024  * an error.
1025  */
1026 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)1027 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
1028 		     struct sta_info *sta,
1029 		     struct ieee802_11_elems *elems,
1030 		     enum ieee80211_self_protected_actioncode ftype,
1031 		     u16 llid, u16 plid)
1032 {
1033 	enum plink_event event = PLINK_UNDEFINED;
1034 	u8 ie_len = elems->peering_len;
1035 	bool matches_local;
1036 
1037 	matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
1038 			 mesh_matches_local(sdata, elems));
1039 
1040 	/* deny open request from non-matching peer */
1041 	if (!matches_local && !sta) {
1042 		event = OPN_RJCT;
1043 		goto out;
1044 	}
1045 
1046 	if (!sta) {
1047 		if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
1048 			mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
1049 			goto out;
1050 		}
1051 		/* ftype == WLAN_SP_MESH_PEERING_OPEN */
1052 		if (!mesh_plink_free_count(sdata)) {
1053 			mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
1054 			goto out;
1055 		}
1056 
1057 		/* new matching peer */
1058 		event = OPN_ACPT;
1059 		goto out;
1060 	} else {
1061 		if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
1062 			mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
1063 			goto out;
1064 		}
1065 		if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
1066 			goto out;
1067 	}
1068 
1069 	switch (ftype) {
1070 	case WLAN_SP_MESH_PEERING_OPEN:
1071 		if (!matches_local)
1072 			event = OPN_RJCT;
1073 		else if (!mesh_plink_free_count(sdata) ||
1074 			 (sta->mesh->plid && sta->mesh->plid != plid))
1075 			event = OPN_IGNR;
1076 		else
1077 			event = OPN_ACPT;
1078 		break;
1079 	case WLAN_SP_MESH_PEERING_CONFIRM:
1080 		if (!matches_local)
1081 			event = CNF_RJCT;
1082 		else if (!mesh_plink_free_count(sdata) ||
1083 			 sta->mesh->llid != llid ||
1084 			 (sta->mesh->plid && sta->mesh->plid != plid))
1085 			event = CNF_IGNR;
1086 		else
1087 			event = CNF_ACPT;
1088 		break;
1089 	case WLAN_SP_MESH_PEERING_CLOSE:
1090 		if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1091 			/* Do not check for llid or plid. This does not
1092 			 * follow the standard but since multiple plinks
1093 			 * per sta are not supported, it is necessary in
1094 			 * order to avoid a livelock when MP A sees an
1095 			 * establish peer link to MP B but MP B does not
1096 			 * see it. This can be caused by a timeout in
1097 			 * B's peer link establishment or B beign
1098 			 * restarted.
1099 			 */
1100 			event = CLS_ACPT;
1101 		else if (sta->mesh->plid != plid)
1102 			event = CLS_IGNR;
1103 		else if (ie_len == 8 && sta->mesh->llid != llid)
1104 			event = CLS_IGNR;
1105 		else
1106 			event = CLS_ACPT;
1107 		break;
1108 	default:
1109 		mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1110 		break;
1111 	}
1112 
1113 out:
1114 	return event;
1115 }
1116 
1117 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)1118 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1119 			 struct ieee80211_mgmt *mgmt,
1120 			 struct ieee802_11_elems *elems,
1121 			 struct ieee80211_rx_status *rx_status)
1122 {
1123 
1124 	struct sta_info *sta;
1125 	enum plink_event event;
1126 	enum ieee80211_self_protected_actioncode ftype;
1127 	u64 changed = 0;
1128 	u8 ie_len = elems->peering_len;
1129 	u16 plid, llid = 0;
1130 
1131 	if (!elems->peering) {
1132 		mpl_dbg(sdata,
1133 			"Mesh plink: missing necessary peer link ie\n");
1134 		return;
1135 	}
1136 
1137 	if (elems->rsn_len &&
1138 	    sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1139 		mpl_dbg(sdata,
1140 			"Mesh plink: can't establish link with secure peer\n");
1141 		return;
1142 	}
1143 
1144 	ftype = mgmt->u.action.u.self_prot.action_code;
1145 	if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1146 	    (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1147 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1148 							&& ie_len != 8)) {
1149 		mpl_dbg(sdata,
1150 			"Mesh plink: incorrect plink ie length %d %d\n",
1151 			ftype, ie_len);
1152 		return;
1153 	}
1154 
1155 	if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1156 	    (!elems->mesh_id || !elems->mesh_config)) {
1157 		mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1158 		return;
1159 	}
1160 	/* Note the lines below are correct, the llid in the frame is the plid
1161 	 * from the point of view of this host.
1162 	 */
1163 	plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1164 	if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1165 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1166 		llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1167 
1168 	/* WARNING: Only for sta pointer, is dropped & re-acquired */
1169 	rcu_read_lock();
1170 
1171 	sta = sta_info_get(sdata, mgmt->sa);
1172 
1173 	if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1174 	    !rssi_threshold_check(sdata, sta)) {
1175 		mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1176 			mgmt->sa);
1177 		goto unlock_rcu;
1178 	}
1179 
1180 	/* Now we will figure out the appropriate event... */
1181 	event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1182 
1183 	if (event == OPN_ACPT) {
1184 		rcu_read_unlock();
1185 		/* allocate sta entry if necessary and update info */
1186 		sta = mesh_sta_info_get(sdata, mgmt->sa, elems, rx_status);
1187 		if (!sta) {
1188 			mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1189 			goto unlock_rcu;
1190 		}
1191 		sta->mesh->plid = plid;
1192 	} else if (!sta && event == OPN_RJCT) {
1193 		mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1194 				    mgmt->sa, 0, plid,
1195 				    WLAN_REASON_MESH_CONFIG);
1196 		goto unlock_rcu;
1197 	} else if (!sta || event == PLINK_UNDEFINED) {
1198 		/* something went wrong */
1199 		goto unlock_rcu;
1200 	}
1201 
1202 	if (event == CNF_ACPT) {
1203 		/* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1204 		if (!sta->mesh->plid)
1205 			sta->mesh->plid = plid;
1206 
1207 		sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1208 	}
1209 
1210 	changed |= mesh_plink_fsm(sdata, sta, event);
1211 
1212 unlock_rcu:
1213 	rcu_read_unlock();
1214 
1215 	if (changed)
1216 		ieee80211_mbss_info_change_notify(sdata, changed);
1217 }
1218 
mesh_rx_plink_frame(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,size_t len,struct ieee80211_rx_status * rx_status)1219 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1220 			 struct ieee80211_mgmt *mgmt, size_t len,
1221 			 struct ieee80211_rx_status *rx_status)
1222 {
1223 	struct ieee802_11_elems *elems;
1224 	size_t baselen;
1225 	u8 *baseaddr;
1226 
1227 	/* need action_code, aux */
1228 	if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1229 		return;
1230 
1231 	if (sdata->u.mesh.user_mpm)
1232 		/* userspace must register for these */
1233 		return;
1234 
1235 	if (is_multicast_ether_addr(mgmt->da)) {
1236 		mpl_dbg(sdata,
1237 			"Mesh plink: ignore frame from multicast address\n");
1238 		return;
1239 	}
1240 
1241 	baseaddr = mgmt->u.action.u.self_prot.variable;
1242 	baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1243 	if (mgmt->u.action.u.self_prot.action_code ==
1244 						WLAN_SP_MESH_PEERING_CONFIRM) {
1245 		baseaddr += 4;
1246 		baselen += 4;
1247 
1248 		if (baselen > len)
1249 			return;
1250 	}
1251 	elems = ieee802_11_parse_elems(baseaddr, len - baselen, true, NULL);
1252 	if (elems) {
1253 		mesh_process_plink_frame(sdata, mgmt, elems, rx_status);
1254 		kfree(elems);
1255 	}
1256 }
1257