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