xref: /linux/net/mac80211/mesh_plink.c (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
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 rate_flags, 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 		rate_flags =
284 			ieee80211_chandef_rate_flags(&sdata->vif.bss_conf.chanreq.oper);
285 		basic_rates = sdata->vif.bss_conf.basic_rates;
286 
287 		if (ieee80211_put_srates_elem(skb, sband, basic_rates,
288 					      rate_flags, 0,
289 					      WLAN_EID_SUPP_RATES) ||
290 		    ieee80211_put_srates_elem(skb, sband, basic_rates,
291 					      rate_flags, 0,
292 					      WLAN_EID_EXT_SUPP_RATES) ||
293 		    mesh_add_rsn_ie(sdata, skb) ||
294 		    mesh_add_meshid_ie(sdata, skb) ||
295 		    mesh_add_meshconf_ie(sdata, skb))
296 			goto free;
297 	} else {	/* WLAN_SP_MESH_PEERING_CLOSE */
298 		info->flags |= IEEE80211_TX_CTL_NO_ACK;
299 		if (mesh_add_meshid_ie(sdata, skb))
300 			goto free;
301 	}
302 
303 	/* Add Mesh Peering Management element */
304 	switch (action) {
305 	case WLAN_SP_MESH_PEERING_OPEN:
306 		break;
307 	case WLAN_SP_MESH_PEERING_CONFIRM:
308 		ie_len += 2;
309 		include_plid = true;
310 		break;
311 	case WLAN_SP_MESH_PEERING_CLOSE:
312 		if (plid) {
313 			ie_len += 2;
314 			include_plid = true;
315 		}
316 		ie_len += 2;	/* reason code */
317 		break;
318 	default:
319 		err = -EINVAL;
320 		goto free;
321 	}
322 
323 	if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
324 		goto free;
325 
326 	pos = skb_put(skb, 2 + ie_len);
327 	*pos++ = WLAN_EID_PEER_MGMT;
328 	*pos++ = ie_len;
329 	memcpy(pos, &peering_proto, 2);
330 	pos += 2;
331 	put_unaligned_le16(llid, pos);
332 	pos += 2;
333 	if (include_plid) {
334 		put_unaligned_le16(plid, pos);
335 		pos += 2;
336 	}
337 	if (action == WLAN_SP_MESH_PEERING_CLOSE) {
338 		put_unaligned_le16(reason, pos);
339 		pos += 2;
340 	}
341 
342 	if (action != WLAN_SP_MESH_PEERING_CLOSE) {
343 		if (mesh_add_ht_cap_ie(sdata, skb) ||
344 		    mesh_add_ht_oper_ie(sdata, skb) ||
345 		    mesh_add_vht_cap_ie(sdata, skb) ||
346 		    mesh_add_vht_oper_ie(sdata, skb) ||
347 		    mesh_add_he_cap_ie(sdata, skb, ie_len_he_cap) ||
348 		    mesh_add_he_oper_ie(sdata, skb) ||
349 		    mesh_add_he_6ghz_cap_ie(sdata, skb) ||
350 		    mesh_add_eht_cap_ie(sdata, skb, ie_len_eht_cap) ||
351 		    mesh_add_eht_oper_ie(sdata, skb))
352 			goto free;
353 	}
354 
355 	if (mesh_add_vendor_ies(sdata, skb))
356 		goto free;
357 
358 	ieee80211_tx_skb(sdata, skb);
359 	return 0;
360 free:
361 	kfree_skb(skb);
362 	return err;
363 }
364 
365 /**
366  * __mesh_plink_deactivate - deactivate mesh peer link
367  *
368  * @sta: mesh peer link to deactivate
369  *
370  * Mesh paths with this peer as next hop should be flushed
371  * by the caller outside of plink_lock.
372  *
373  * Returns: beacon changed flag if the beacon content changed.
374  *
375  * Locking: the caller must hold sta->mesh->plink_lock
376  */
__mesh_plink_deactivate(struct sta_info * sta)377 static u64 __mesh_plink_deactivate(struct sta_info *sta)
378 {
379 	struct ieee80211_sub_if_data *sdata = sta->sdata;
380 	u64 changed = 0;
381 
382 	lockdep_assert_held(&sta->mesh->plink_lock);
383 
384 	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
385 		changed = mesh_plink_dec_estab_count(sdata);
386 	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
387 
388 	ieee80211_mps_sta_status_update(sta);
389 	changed |= ieee80211_mps_set_sta_local_pm(sta,
390 			NL80211_MESH_POWER_UNKNOWN);
391 
392 	return changed;
393 }
394 
395 /**
396  * mesh_plink_deactivate - deactivate mesh peer link
397  *
398  * @sta: mesh peer link to deactivate
399  *
400  * All mesh paths with this peer as next hop will be flushed
401  *
402  * Returns: beacon changed flag if the beacon content changed.
403  */
mesh_plink_deactivate(struct sta_info * sta)404 u64 mesh_plink_deactivate(struct sta_info *sta)
405 {
406 	struct ieee80211_sub_if_data *sdata = sta->sdata;
407 	u64 changed;
408 
409 	spin_lock_bh(&sta->mesh->plink_lock);
410 	changed = __mesh_plink_deactivate(sta);
411 
412 	if (!sdata->u.mesh.user_mpm) {
413 		sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
414 		mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
415 				    sta->sta.addr, sta->mesh->llid,
416 				    sta->mesh->plid, sta->mesh->reason);
417 	}
418 	spin_unlock_bh(&sta->mesh->plink_lock);
419 	if (!sdata->u.mesh.user_mpm)
420 		del_timer_sync(&sta->mesh->plink_timer);
421 	mesh_path_flush_by_nexthop(sta);
422 
423 	/* make sure no readers can access nexthop sta from here on */
424 	synchronize_net();
425 
426 	return changed;
427 }
428 
mesh_sta_info_init(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,struct ieee802_11_elems * elems)429 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
430 			       struct sta_info *sta,
431 			       struct ieee802_11_elems *elems)
432 {
433 	struct ieee80211_local *local = sdata->local;
434 	struct ieee80211_supported_band *sband;
435 	u32 rates, basic_rates = 0, changed = 0;
436 	enum ieee80211_sta_rx_bandwidth bw = sta->sta.deflink.bandwidth;
437 
438 	sband = ieee80211_get_sband(sdata);
439 	if (!sband)
440 		return;
441 
442 	rates = ieee80211_sta_get_rates(sdata, elems, sband->band,
443 					&basic_rates);
444 
445 	spin_lock_bh(&sta->mesh->plink_lock);
446 	sta->deflink.rx_stats.last_rx = jiffies;
447 
448 	/* rates and capabilities don't change during peering */
449 	if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
450 	    sta->mesh->processed_beacon)
451 		goto out;
452 	sta->mesh->processed_beacon = true;
453 
454 	if (sta->sta.deflink.supp_rates[sband->band] != rates)
455 		changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
456 	sta->sta.deflink.supp_rates[sband->band] = rates;
457 
458 	if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
459 					      elems->ht_cap_elem,
460 					      &sta->deflink))
461 		changed |= IEEE80211_RC_BW_CHANGED;
462 
463 	ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
464 					    elems->vht_cap_elem, NULL,
465 					    &sta->deflink);
466 
467 	ieee80211_he_cap_ie_to_sta_he_cap(sdata, sband, elems->he_cap,
468 					  elems->he_cap_len,
469 					  elems->he_6ghz_capa,
470 					  &sta->deflink);
471 
472 	ieee80211_eht_cap_ie_to_sta_eht_cap(sdata, sband, elems->he_cap,
473 					    elems->he_cap_len,
474 					    elems->eht_cap, elems->eht_cap_len,
475 					    &sta->deflink);
476 
477 	if (bw != sta->sta.deflink.bandwidth)
478 		changed |= IEEE80211_RC_BW_CHANGED;
479 
480 	/* HT peer is operating 20MHz-only */
481 	if (elems->ht_operation &&
482 	    !(elems->ht_operation->ht_param &
483 	      IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
484 		if (sta->sta.deflink.bandwidth != IEEE80211_STA_RX_BW_20)
485 			changed |= IEEE80211_RC_BW_CHANGED;
486 		sta->sta.deflink.bandwidth = IEEE80211_STA_RX_BW_20;
487 	}
488 
489 	if (!test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
490 		rate_control_rate_init(sta);
491 	else
492 		rate_control_rate_update(local, sband, sta, 0, changed);
493 out:
494 	spin_unlock_bh(&sta->mesh->plink_lock);
495 }
496 
mesh_allocate_aid(struct ieee80211_sub_if_data * sdata)497 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
498 {
499 	struct sta_info *sta;
500 	unsigned long *aid_map;
501 	int aid;
502 
503 	aid_map = bitmap_zalloc(IEEE80211_MAX_AID + 1, GFP_KERNEL);
504 	if (!aid_map)
505 		return -ENOMEM;
506 
507 	/* reserve aid 0 for mcast indication */
508 	__set_bit(0, aid_map);
509 
510 	rcu_read_lock();
511 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
512 		__set_bit(sta->sta.aid, aid_map);
513 	rcu_read_unlock();
514 
515 	aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
516 	bitmap_free(aid_map);
517 
518 	if (aid > IEEE80211_MAX_AID)
519 		return -ENOBUFS;
520 
521 	return aid;
522 }
523 
524 static struct sta_info *
__mesh_sta_info_alloc(struct ieee80211_sub_if_data * sdata,u8 * hw_addr)525 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
526 {
527 	struct sta_info *sta;
528 	int aid;
529 
530 	if (sdata->local->num_sta >= MESH_MAX_PLINKS)
531 		return NULL;
532 
533 	aid = mesh_allocate_aid(sdata);
534 	if (aid < 0)
535 		return NULL;
536 
537 	sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
538 	if (!sta)
539 		return NULL;
540 
541 	sta->mesh->plink_state = NL80211_PLINK_LISTEN;
542 	sta->sta.wme = true;
543 	sta->sta.aid = aid;
544 
545 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
546 	sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
547 	sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
548 
549 	return sta;
550 }
551 
552 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)553 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
554 		    struct ieee802_11_elems *elems,
555 		    struct ieee80211_rx_status *rx_status)
556 {
557 	struct sta_info *sta = NULL;
558 
559 	/* Userspace handles station allocation */
560 	if (sdata->u.mesh.user_mpm ||
561 	    sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
562 		if (mesh_peer_accepts_plinks(elems) &&
563 		    mesh_plink_availables(sdata)) {
564 			int sig = 0;
565 
566 			if (ieee80211_hw_check(&sdata->local->hw, SIGNAL_DBM))
567 				sig = rx_status->signal;
568 
569 			cfg80211_notify_new_peer_candidate(sdata->dev, addr,
570 							   elems->ie_start,
571 							   elems->total_len,
572 							   sig, GFP_KERNEL);
573 		}
574 	} else
575 		sta = __mesh_sta_info_alloc(sdata, addr);
576 
577 	return sta;
578 }
579 
580 /*
581  * mesh_sta_info_get - return mesh sta info entry for @addr.
582  *
583  * @sdata: local meshif
584  * @addr: peer's address
585  * @elems: IEs from beacon or mesh peering frame.
586  * @rx_status: rx status for the frame for signal reporting
587  *
588  * Return existing or newly allocated sta_info under RCU read lock.
589  * (re)initialize with given IEs.
590  */
591 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)592 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
593 		  u8 *addr, struct ieee802_11_elems *elems,
594 		  struct ieee80211_rx_status *rx_status) __acquires(RCU)
595 {
596 	struct sta_info *sta = NULL;
597 
598 	rcu_read_lock();
599 	sta = sta_info_get(sdata, addr);
600 	if (sta) {
601 		mesh_sta_info_init(sdata, sta, elems);
602 	} else {
603 		rcu_read_unlock();
604 		/* can't run atomic */
605 		sta = mesh_sta_info_alloc(sdata, addr, elems, rx_status);
606 		if (!sta) {
607 			rcu_read_lock();
608 			return NULL;
609 		}
610 
611 		mesh_sta_info_init(sdata, sta, elems);
612 
613 		if (sta_info_insert_rcu(sta))
614 			return NULL;
615 	}
616 
617 	return sta;
618 }
619 
620 /*
621  * mesh_neighbour_update - update or initialize new mesh neighbor.
622  *
623  * @sdata: local meshif
624  * @addr: peer's address
625  * @elems: IEs from beacon or mesh peering frame
626  * @rx_status: rx status for the frame for signal reporting
627  *
628  * Initiates peering if appropriate.
629  */
mesh_neighbour_update(struct ieee80211_sub_if_data * sdata,u8 * hw_addr,struct ieee802_11_elems * elems,struct ieee80211_rx_status * rx_status)630 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
631 			   u8 *hw_addr,
632 			   struct ieee802_11_elems *elems,
633 			   struct ieee80211_rx_status *rx_status)
634 {
635 	struct sta_info *sta;
636 	u64 changed = 0;
637 
638 	sta = mesh_sta_info_get(sdata, hw_addr, elems, rx_status);
639 	if (!sta)
640 		goto out;
641 
642 	sta->mesh->connected_to_gate = elems->mesh_config->meshconf_form &
643 		IEEE80211_MESHCONF_FORM_CONNECTED_TO_GATE;
644 
645 	if (mesh_peer_accepts_plinks(elems) &&
646 	    sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
647 	    sdata->u.mesh.accepting_plinks &&
648 	    sdata->u.mesh.mshcfg.auto_open_plinks &&
649 	    rssi_threshold_check(sdata, sta))
650 		changed = mesh_plink_open(sta);
651 
652 	ieee80211_mps_frame_release(sta, elems);
653 out:
654 	rcu_read_unlock();
655 	ieee80211_mbss_info_change_notify(sdata, changed);
656 }
657 
mesh_plink_timer(struct timer_list * t)658 void mesh_plink_timer(struct timer_list *t)
659 {
660 	struct mesh_sta *mesh = from_timer(mesh, t, plink_timer);
661 	struct sta_info *sta;
662 	u16 reason = 0;
663 	struct ieee80211_sub_if_data *sdata;
664 	struct mesh_config *mshcfg;
665 	enum ieee80211_self_protected_actioncode action = 0;
666 
667 	/*
668 	 * This STA is valid because sta_info_destroy() will
669 	 * del_timer_sync() this timer after having made sure
670 	 * it cannot be readded (by deleting the plink.)
671 	 */
672 	sta = mesh->plink_sta;
673 
674 	if (sta->sdata->local->quiescing)
675 		return;
676 
677 	spin_lock_bh(&sta->mesh->plink_lock);
678 
679 	/* If a timer fires just before a state transition on another CPU,
680 	 * we may have already extended the timeout and changed state by the
681 	 * time we've acquired the lock and arrived  here.  In that case,
682 	 * skip this timer and wait for the new one.
683 	 */
684 	if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
685 		mpl_dbg(sta->sdata,
686 			"Ignoring timer for %pM in state %s (timer adjusted)",
687 			sta->sta.addr, mplstates[sta->mesh->plink_state]);
688 		spin_unlock_bh(&sta->mesh->plink_lock);
689 		return;
690 	}
691 
692 	/* del_timer() and handler may race when entering these states */
693 	if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
694 	    sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
695 		mpl_dbg(sta->sdata,
696 			"Ignoring timer for %pM in state %s (timer deleted)",
697 			sta->sta.addr, mplstates[sta->mesh->plink_state]);
698 		spin_unlock_bh(&sta->mesh->plink_lock);
699 		return;
700 	}
701 
702 	mpl_dbg(sta->sdata,
703 		"Mesh plink timer for %pM fired on state %s\n",
704 		sta->sta.addr, mplstates[sta->mesh->plink_state]);
705 	sdata = sta->sdata;
706 	mshcfg = &sdata->u.mesh.mshcfg;
707 
708 	switch (sta->mesh->plink_state) {
709 	case NL80211_PLINK_OPN_RCVD:
710 	case NL80211_PLINK_OPN_SNT:
711 		/* retry timer */
712 		if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
713 			u32 rand;
714 			mpl_dbg(sta->sdata,
715 				"Mesh plink for %pM (retry, timeout): %d %d\n",
716 				sta->sta.addr, sta->mesh->plink_retries,
717 				sta->mesh->plink_timeout);
718 			get_random_bytes(&rand, sizeof(u32));
719 			sta->mesh->plink_timeout = sta->mesh->plink_timeout +
720 					     rand % sta->mesh->plink_timeout;
721 			++sta->mesh->plink_retries;
722 			mod_plink_timer(sta, sta->mesh->plink_timeout);
723 			action = WLAN_SP_MESH_PEERING_OPEN;
724 			break;
725 		}
726 		reason = WLAN_REASON_MESH_MAX_RETRIES;
727 		fallthrough;
728 	case NL80211_PLINK_CNF_RCVD:
729 		/* confirm timer */
730 		if (!reason)
731 			reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
732 		sta->mesh->plink_state = NL80211_PLINK_HOLDING;
733 		mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
734 		action = WLAN_SP_MESH_PEERING_CLOSE;
735 		break;
736 	case NL80211_PLINK_HOLDING:
737 		/* holding timer */
738 		del_timer(&sta->mesh->plink_timer);
739 		mesh_plink_fsm_restart(sta);
740 		break;
741 	default:
742 		break;
743 	}
744 	spin_unlock_bh(&sta->mesh->plink_lock);
745 	if (action)
746 		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
747 				    sta->mesh->llid, sta->mesh->plid, reason);
748 }
749 
mesh_plink_timer_set(struct sta_info * sta,u32 timeout)750 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
751 {
752 	sta->mesh->plink_timeout = timeout;
753 	mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
754 }
755 
llid_in_use(struct ieee80211_sub_if_data * sdata,u16 llid)756 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
757 			u16 llid)
758 {
759 	struct ieee80211_local *local = sdata->local;
760 	bool in_use = false;
761 	struct sta_info *sta;
762 
763 	rcu_read_lock();
764 	list_for_each_entry_rcu(sta, &local->sta_list, list) {
765 		if (sdata != sta->sdata)
766 			continue;
767 
768 		if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
769 			in_use = true;
770 			break;
771 		}
772 	}
773 	rcu_read_unlock();
774 
775 	return in_use;
776 }
777 
mesh_get_new_llid(struct ieee80211_sub_if_data * sdata)778 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
779 {
780 	u16 llid;
781 
782 	do {
783 		get_random_bytes(&llid, sizeof(llid));
784 	} while (llid_in_use(sdata, llid));
785 
786 	return llid;
787 }
788 
mesh_plink_open(struct sta_info * sta)789 u64 mesh_plink_open(struct sta_info *sta)
790 {
791 	struct ieee80211_sub_if_data *sdata = sta->sdata;
792 	u64 changed;
793 
794 	if (!test_sta_flag(sta, WLAN_STA_AUTH))
795 		return 0;
796 
797 	spin_lock_bh(&sta->mesh->plink_lock);
798 	sta->mesh->llid = mesh_get_new_llid(sdata);
799 	if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
800 	    sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
801 		spin_unlock_bh(&sta->mesh->plink_lock);
802 		return 0;
803 	}
804 	sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
805 	mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
806 	spin_unlock_bh(&sta->mesh->plink_lock);
807 	mpl_dbg(sdata,
808 		"Mesh plink: starting establishment with %pM\n",
809 		sta->sta.addr);
810 
811 	/* set the non-peer mode to active during peering */
812 	changed = ieee80211_mps_local_status_update(sdata);
813 
814 	mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
815 			    sta->sta.addr, sta->mesh->llid, 0, 0);
816 	return changed;
817 }
818 
mesh_plink_block(struct sta_info * sta)819 u64 mesh_plink_block(struct sta_info *sta)
820 {
821 	u64 changed;
822 
823 	spin_lock_bh(&sta->mesh->plink_lock);
824 	changed = __mesh_plink_deactivate(sta);
825 	sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
826 	spin_unlock_bh(&sta->mesh->plink_lock);
827 	mesh_path_flush_by_nexthop(sta);
828 
829 	return changed;
830 }
831 
mesh_plink_close(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum plink_event event)832 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
833 			     struct sta_info *sta,
834 			     enum plink_event event)
835 {
836 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
837 	u16 reason = (event == CLS_ACPT) ?
838 		     WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
839 
840 	sta->mesh->reason = reason;
841 	sta->mesh->plink_state = NL80211_PLINK_HOLDING;
842 	mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
843 }
844 
mesh_plink_establish(struct ieee80211_sub_if_data * sdata,struct sta_info * sta)845 static u64 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
846 				struct sta_info *sta)
847 {
848 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
849 	u64 changed = 0;
850 
851 	del_timer(&sta->mesh->plink_timer);
852 	sta->mesh->plink_state = NL80211_PLINK_ESTAB;
853 	changed |= mesh_plink_inc_estab_count(sdata);
854 	changed |= mesh_set_ht_prot_mode(sdata);
855 	changed |= mesh_set_short_slot_time(sdata);
856 	mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
857 	ieee80211_mps_sta_status_update(sta);
858 	changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
859 	return changed;
860 }
861 
862 /**
863  * mesh_plink_fsm - step @sta MPM based on @event
864  *
865  * @sdata: interface
866  * @sta: mesh neighbor
867  * @event: peering event
868  *
869  * Return: changed MBSS flags
870  */
mesh_plink_fsm(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum plink_event event)871 static u64 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
872 			  struct sta_info *sta, enum plink_event event)
873 {
874 	struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
875 	enum ieee80211_self_protected_actioncode action = 0;
876 	u64 changed = 0;
877 	bool flush = false;
878 
879 	mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
880 		mplstates[sta->mesh->plink_state], mplevents[event]);
881 
882 	spin_lock_bh(&sta->mesh->plink_lock);
883 	switch (sta->mesh->plink_state) {
884 	case NL80211_PLINK_LISTEN:
885 		switch (event) {
886 		case CLS_ACPT:
887 			mesh_plink_fsm_restart(sta);
888 			break;
889 		case OPN_ACPT:
890 			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
891 			sta->mesh->llid = mesh_get_new_llid(sdata);
892 			mesh_plink_timer_set(sta,
893 					     mshcfg->dot11MeshRetryTimeout);
894 
895 			/* set the non-peer mode to active during peering */
896 			changed |= ieee80211_mps_local_status_update(sdata);
897 			action = WLAN_SP_MESH_PEERING_OPEN;
898 			break;
899 		default:
900 			break;
901 		}
902 		break;
903 	case NL80211_PLINK_OPN_SNT:
904 		switch (event) {
905 		case OPN_RJCT:
906 		case CNF_RJCT:
907 		case CLS_ACPT:
908 			mesh_plink_close(sdata, sta, event);
909 			action = WLAN_SP_MESH_PEERING_CLOSE;
910 			break;
911 		case OPN_ACPT:
912 			/* retry timer is left untouched */
913 			sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
914 			action = WLAN_SP_MESH_PEERING_CONFIRM;
915 			break;
916 		case CNF_ACPT:
917 			sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
918 			mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
919 			break;
920 		default:
921 			break;
922 		}
923 		break;
924 	case NL80211_PLINK_OPN_RCVD:
925 		switch (event) {
926 		case OPN_RJCT:
927 		case CNF_RJCT:
928 		case CLS_ACPT:
929 			mesh_plink_close(sdata, sta, event);
930 			action = WLAN_SP_MESH_PEERING_CLOSE;
931 			break;
932 		case OPN_ACPT:
933 			action = WLAN_SP_MESH_PEERING_CONFIRM;
934 			break;
935 		case CNF_ACPT:
936 			changed |= mesh_plink_establish(sdata, sta);
937 			break;
938 		default:
939 			break;
940 		}
941 		break;
942 	case NL80211_PLINK_CNF_RCVD:
943 		switch (event) {
944 		case OPN_RJCT:
945 		case CNF_RJCT:
946 		case CLS_ACPT:
947 			mesh_plink_close(sdata, sta, event);
948 			action = WLAN_SP_MESH_PEERING_CLOSE;
949 			break;
950 		case OPN_ACPT:
951 			changed |= mesh_plink_establish(sdata, sta);
952 			action = WLAN_SP_MESH_PEERING_CONFIRM;
953 			break;
954 		default:
955 			break;
956 		}
957 		break;
958 	case NL80211_PLINK_ESTAB:
959 		switch (event) {
960 		case CLS_ACPT:
961 			changed |= __mesh_plink_deactivate(sta);
962 			changed |= mesh_set_ht_prot_mode(sdata);
963 			changed |= mesh_set_short_slot_time(sdata);
964 			mesh_plink_close(sdata, sta, event);
965 			action = WLAN_SP_MESH_PEERING_CLOSE;
966 			flush = true;
967 			break;
968 		case OPN_ACPT:
969 			action = WLAN_SP_MESH_PEERING_CONFIRM;
970 			break;
971 		default:
972 			break;
973 		}
974 		break;
975 	case NL80211_PLINK_HOLDING:
976 		switch (event) {
977 		case CLS_ACPT:
978 			del_timer(&sta->mesh->plink_timer);
979 			mesh_plink_fsm_restart(sta);
980 			break;
981 		case OPN_ACPT:
982 		case CNF_ACPT:
983 		case OPN_RJCT:
984 		case CNF_RJCT:
985 			action = WLAN_SP_MESH_PEERING_CLOSE;
986 			break;
987 		default:
988 			break;
989 		}
990 		break;
991 	default:
992 		/* should not get here, PLINK_BLOCKED is dealt with at the
993 		 * beginning of the function
994 		 */
995 		break;
996 	}
997 	spin_unlock_bh(&sta->mesh->plink_lock);
998 	if (flush)
999 		mesh_path_flush_by_nexthop(sta);
1000 	if (action) {
1001 		mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
1002 				    sta->mesh->llid, sta->mesh->plid,
1003 				    sta->mesh->reason);
1004 
1005 		/* also send confirm in open case */
1006 		if (action == WLAN_SP_MESH_PEERING_OPEN) {
1007 			mesh_plink_frame_tx(sdata, sta,
1008 					    WLAN_SP_MESH_PEERING_CONFIRM,
1009 					    sta->sta.addr, sta->mesh->llid,
1010 					    sta->mesh->plid, 0);
1011 		}
1012 	}
1013 
1014 	return changed;
1015 }
1016 
1017 /*
1018  * mesh_plink_get_event - get correct MPM event
1019  *
1020  * @sdata: interface
1021  * @sta: peer, leave NULL if processing a frame from a new suitable peer
1022  * @elems: peering management IEs
1023  * @ftype: frame type
1024  * @llid: peer's peer link ID
1025  * @plid: peer's local link ID
1026  *
1027  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
1028  * an error.
1029  */
1030 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)1031 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
1032 		     struct sta_info *sta,
1033 		     struct ieee802_11_elems *elems,
1034 		     enum ieee80211_self_protected_actioncode ftype,
1035 		     u16 llid, u16 plid)
1036 {
1037 	enum plink_event event = PLINK_UNDEFINED;
1038 	u8 ie_len = elems->peering_len;
1039 	bool matches_local;
1040 
1041 	matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
1042 			 mesh_matches_local(sdata, elems));
1043 
1044 	/* deny open request from non-matching peer */
1045 	if (!matches_local && !sta) {
1046 		event = OPN_RJCT;
1047 		goto out;
1048 	}
1049 
1050 	if (!sta) {
1051 		if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
1052 			mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
1053 			goto out;
1054 		}
1055 		/* ftype == WLAN_SP_MESH_PEERING_OPEN */
1056 		if (!mesh_plink_free_count(sdata)) {
1057 			mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
1058 			goto out;
1059 		}
1060 
1061 		/* new matching peer */
1062 		event = OPN_ACPT;
1063 		goto out;
1064 	} else {
1065 		if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
1066 			mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
1067 			goto out;
1068 		}
1069 		if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
1070 			goto out;
1071 	}
1072 
1073 	switch (ftype) {
1074 	case WLAN_SP_MESH_PEERING_OPEN:
1075 		if (!matches_local)
1076 			event = OPN_RJCT;
1077 		else if (!mesh_plink_free_count(sdata) ||
1078 			 (sta->mesh->plid && sta->mesh->plid != plid))
1079 			event = OPN_IGNR;
1080 		else
1081 			event = OPN_ACPT;
1082 		break;
1083 	case WLAN_SP_MESH_PEERING_CONFIRM:
1084 		if (!matches_local)
1085 			event = CNF_RJCT;
1086 		else if (!mesh_plink_free_count(sdata) ||
1087 			 sta->mesh->llid != llid ||
1088 			 (sta->mesh->plid && sta->mesh->plid != plid))
1089 			event = CNF_IGNR;
1090 		else
1091 			event = CNF_ACPT;
1092 		break;
1093 	case WLAN_SP_MESH_PEERING_CLOSE:
1094 		if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1095 			/* Do not check for llid or plid. This does not
1096 			 * follow the standard but since multiple plinks
1097 			 * per sta are not supported, it is necessary in
1098 			 * order to avoid a livelock when MP A sees an
1099 			 * establish peer link to MP B but MP B does not
1100 			 * see it. This can be caused by a timeout in
1101 			 * B's peer link establishment or B beign
1102 			 * restarted.
1103 			 */
1104 			event = CLS_ACPT;
1105 		else if (sta->mesh->plid != plid)
1106 			event = CLS_IGNR;
1107 		else if (ie_len == 8 && sta->mesh->llid != llid)
1108 			event = CLS_IGNR;
1109 		else
1110 			event = CLS_ACPT;
1111 		break;
1112 	default:
1113 		mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1114 		break;
1115 	}
1116 
1117 out:
1118 	return event;
1119 }
1120 
1121 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)1122 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1123 			 struct ieee80211_mgmt *mgmt,
1124 			 struct ieee802_11_elems *elems,
1125 			 struct ieee80211_rx_status *rx_status)
1126 {
1127 
1128 	struct sta_info *sta;
1129 	enum plink_event event;
1130 	enum ieee80211_self_protected_actioncode ftype;
1131 	u64 changed = 0;
1132 	u8 ie_len = elems->peering_len;
1133 	u16 plid, llid = 0;
1134 
1135 	if (!elems->peering) {
1136 		mpl_dbg(sdata,
1137 			"Mesh plink: missing necessary peer link ie\n");
1138 		return;
1139 	}
1140 
1141 	if (elems->rsn_len &&
1142 	    sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1143 		mpl_dbg(sdata,
1144 			"Mesh plink: can't establish link with secure peer\n");
1145 		return;
1146 	}
1147 
1148 	ftype = mgmt->u.action.u.self_prot.action_code;
1149 	if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1150 	    (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1151 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1152 							&& ie_len != 8)) {
1153 		mpl_dbg(sdata,
1154 			"Mesh plink: incorrect plink ie length %d %d\n",
1155 			ftype, ie_len);
1156 		return;
1157 	}
1158 
1159 	if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1160 	    (!elems->mesh_id || !elems->mesh_config)) {
1161 		mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1162 		return;
1163 	}
1164 	/* Note the lines below are correct, the llid in the frame is the plid
1165 	 * from the point of view of this host.
1166 	 */
1167 	plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1168 	if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1169 	    (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1170 		llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1171 
1172 	/* WARNING: Only for sta pointer, is dropped & re-acquired */
1173 	rcu_read_lock();
1174 
1175 	sta = sta_info_get(sdata, mgmt->sa);
1176 
1177 	if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1178 	    !rssi_threshold_check(sdata, sta)) {
1179 		mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1180 			mgmt->sa);
1181 		goto unlock_rcu;
1182 	}
1183 
1184 	/* Now we will figure out the appropriate event... */
1185 	event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1186 
1187 	if (event == OPN_ACPT) {
1188 		rcu_read_unlock();
1189 		/* allocate sta entry if necessary and update info */
1190 		sta = mesh_sta_info_get(sdata, mgmt->sa, elems, rx_status);
1191 		if (!sta) {
1192 			mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1193 			goto unlock_rcu;
1194 		}
1195 		sta->mesh->plid = plid;
1196 	} else if (!sta && event == OPN_RJCT) {
1197 		mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1198 				    mgmt->sa, 0, plid,
1199 				    WLAN_REASON_MESH_CONFIG);
1200 		goto unlock_rcu;
1201 	} else if (!sta || event == PLINK_UNDEFINED) {
1202 		/* something went wrong */
1203 		goto unlock_rcu;
1204 	}
1205 
1206 	if (event == CNF_ACPT) {
1207 		/* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1208 		if (!sta->mesh->plid)
1209 			sta->mesh->plid = plid;
1210 
1211 		sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1212 	}
1213 
1214 	changed |= mesh_plink_fsm(sdata, sta, event);
1215 
1216 unlock_rcu:
1217 	rcu_read_unlock();
1218 
1219 	if (changed)
1220 		ieee80211_mbss_info_change_notify(sdata, changed);
1221 }
1222 
mesh_rx_plink_frame(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,size_t len,struct ieee80211_rx_status * rx_status)1223 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1224 			 struct ieee80211_mgmt *mgmt, size_t len,
1225 			 struct ieee80211_rx_status *rx_status)
1226 {
1227 	struct ieee802_11_elems *elems;
1228 	size_t baselen;
1229 	u8 *baseaddr;
1230 
1231 	/* need action_code, aux */
1232 	if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1233 		return;
1234 
1235 	if (sdata->u.mesh.user_mpm)
1236 		/* userspace must register for these */
1237 		return;
1238 
1239 	if (is_multicast_ether_addr(mgmt->da)) {
1240 		mpl_dbg(sdata,
1241 			"Mesh plink: ignore frame from multicast address\n");
1242 		return;
1243 	}
1244 
1245 	baseaddr = mgmt->u.action.u.self_prot.variable;
1246 	baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1247 	if (mgmt->u.action.u.self_prot.action_code ==
1248 						WLAN_SP_MESH_PEERING_CONFIRM) {
1249 		baseaddr += 4;
1250 		baselen += 4;
1251 
1252 		if (baselen > len)
1253 			return;
1254 	}
1255 	elems = ieee802_11_parse_elems(baseaddr, len - baselen, true, NULL);
1256 	if (elems) {
1257 		mesh_process_plink_frame(sdata, mgmt, elems, rx_status);
1258 		kfree(elems);
1259 	}
1260 }
1261