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Linux/net/mac80211/mesh_plink.c

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  1 /*
  2  * Copyright (c) 2008, 2009 open80211s Ltd.
  3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
  4  *
  5  * This program is free software; you can redistribute it and/or modify
  6  * it under the terms of the GNU General Public License version 2 as
  7  * published by the Free Software Foundation.
  8  */
  9 #include <linux/gfp.h>
 10 #include <linux/kernel.h>
 11 #include <linux/random.h>
 12 #include "ieee80211_i.h"
 13 #include "rate.h"
 14 #include "mesh.h"
 15 
 16 #define PLINK_GET_LLID(p) (p + 2)
 17 #define PLINK_GET_PLID(p) (p + 4)
 18 
 19 #define mod_plink_timer(s, t) (mod_timer(&s->plink_timer, \
 20                                 jiffies + HZ * t / 1000))
 21 
 22 enum plink_event {
 23         PLINK_UNDEFINED,
 24         OPN_ACPT,
 25         OPN_RJCT,
 26         OPN_IGNR,
 27         CNF_ACPT,
 28         CNF_RJCT,
 29         CNF_IGNR,
 30         CLS_ACPT,
 31         CLS_IGNR
 32 };
 33 
 34 static const char * const mplstates[] = {
 35         [NL80211_PLINK_LISTEN] = "LISTEN",
 36         [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 37         [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 38         [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 39         [NL80211_PLINK_ESTAB] = "ESTAB",
 40         [NL80211_PLINK_HOLDING] = "HOLDING",
 41         [NL80211_PLINK_BLOCKED] = "BLOCKED"
 42 };
 43 
 44 static const char * const mplevents[] = {
 45         [PLINK_UNDEFINED] = "NONE",
 46         [OPN_ACPT] = "OPN_ACPT",
 47         [OPN_RJCT] = "OPN_RJCT",
 48         [OPN_IGNR] = "OPN_IGNR",
 49         [CNF_ACPT] = "CNF_ACPT",
 50         [CNF_RJCT] = "CNF_RJCT",
 51         [CNF_IGNR] = "CNF_IGNR",
 52         [CLS_ACPT] = "CLS_ACPT",
 53         [CLS_IGNR] = "CLS_IGNR"
 54 };
 55 
 56 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 57                                enum ieee80211_self_protected_actioncode action,
 58                                u8 *da, u16 llid, u16 plid, u16 reason);
 59 
 60 
 61 /* We only need a valid sta if user configured a minimum rssi_threshold. */
 62 static bool rssi_threshold_check(struct ieee80211_sub_if_data *sdata,
 63                                  struct sta_info *sta)
 64 {
 65         s32 rssi_threshold = sdata->u.mesh.mshcfg.rssi_threshold;
 66         return rssi_threshold == 0 ||
 67                (sta && (s8) -ewma_read(&sta->avg_signal) > rssi_threshold);
 68 }
 69 
 70 /**
 71  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
 72  *
 73  * @sta: mesh peer link to restart
 74  *
 75  * Locking: this function must be called holding sta->lock
 76  */
 77 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
 78 {
 79         sta->plink_state = NL80211_PLINK_LISTEN;
 80         sta->llid = sta->plid = sta->reason = 0;
 81         sta->plink_retries = 0;
 82 }
 83 
 84 /*
 85  * mesh_set_short_slot_time - enable / disable ERP short slot time.
 86  *
 87  * The standard indirectly mandates mesh STAs to turn off short slot time by
 88  * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
 89  * can't be sneaky about it. Enable short slot time if all mesh STAs in the
 90  * MBSS support ERP rates.
 91  *
 92  * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
 93  */
 94 static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
 95 {
 96         struct ieee80211_local *local = sdata->local;
 97         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 98         struct ieee80211_supported_band *sband = local->hw.wiphy->bands[band];
 99         struct sta_info *sta;
100         u32 erp_rates = 0, changed = 0;
101         int i;
102         bool short_slot = false;
103 
104         if (band == IEEE80211_BAND_5GHZ) {
105                 /* (IEEE 802.11-2012 19.4.5) */
106                 short_slot = true;
107                 goto out;
108         } else if (band != IEEE80211_BAND_2GHZ ||
109                    (band == IEEE80211_BAND_2GHZ &&
110                     local->hw.flags & IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE))
111                 goto out;
112 
113         for (i = 0; i < sband->n_bitrates; i++)
114                 if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
115                         erp_rates |= BIT(i);
116 
117         if (!erp_rates)
118                 goto out;
119 
120         rcu_read_lock();
121         list_for_each_entry_rcu(sta, &local->sta_list, list) {
122                 if (sdata != sta->sdata ||
123                     sta->plink_state != NL80211_PLINK_ESTAB)
124                         continue;
125 
126                 short_slot = false;
127                 if (erp_rates & sta->sta.supp_rates[band])
128                         short_slot = true;
129                  else
130                         break;
131         }
132         rcu_read_unlock();
133 
134 out:
135         if (sdata->vif.bss_conf.use_short_slot != short_slot) {
136                 sdata->vif.bss_conf.use_short_slot = short_slot;
137                 changed = BSS_CHANGED_ERP_SLOT;
138                 mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
139                         sdata->vif.addr, short_slot);
140         }
141         return changed;
142 }
143 
144 /**
145  * mesh_set_ht_prot_mode - set correct HT protection mode
146  *
147  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
148  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
149  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
150  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
151  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
152  * HT20 peer is present. Otherwise no-protection mode is selected.
153  */
154 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
155 {
156         struct ieee80211_local *local = sdata->local;
157         struct sta_info *sta;
158         u16 ht_opmode;
159         bool non_ht_sta = false, ht20_sta = false;
160 
161         switch (sdata->vif.bss_conf.chandef.width) {
162         case NL80211_CHAN_WIDTH_20_NOHT:
163         case NL80211_CHAN_WIDTH_5:
164         case NL80211_CHAN_WIDTH_10:
165                 return 0;
166         default:
167                 break;
168         }
169 
170         rcu_read_lock();
171         list_for_each_entry_rcu(sta, &local->sta_list, list) {
172                 if (sdata != sta->sdata ||
173                     sta->plink_state != NL80211_PLINK_ESTAB)
174                         continue;
175 
176                 if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
177                         continue;
178 
179                 if (!sta->sta.ht_cap.ht_supported) {
180                         mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
181                                        sta->sta.addr);
182                         non_ht_sta = true;
183                         break;
184                 }
185 
186                 mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
187                 ht20_sta = true;
188         }
189         rcu_read_unlock();
190 
191         if (non_ht_sta)
192                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
193         else if (ht20_sta &&
194                  sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
195                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
196         else
197                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
198 
199         if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
200                 return 0;
201 
202         sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
203         sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
204         mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
205         return BSS_CHANGED_HT;
206 }
207 
208 /**
209  * __mesh_plink_deactivate - deactivate mesh peer link
210  *
211  * @sta: mesh peer link to deactivate
212  *
213  * All mesh paths with this peer as next hop will be flushed
214  * Returns beacon changed flag if the beacon content changed.
215  *
216  * Locking: the caller must hold sta->lock
217  */
218 static u32 __mesh_plink_deactivate(struct sta_info *sta)
219 {
220         struct ieee80211_sub_if_data *sdata = sta->sdata;
221         u32 changed = 0;
222 
223         if (sta->plink_state == NL80211_PLINK_ESTAB)
224                 changed = mesh_plink_dec_estab_count(sdata);
225         sta->plink_state = NL80211_PLINK_BLOCKED;
226         mesh_path_flush_by_nexthop(sta);
227 
228         ieee80211_mps_sta_status_update(sta);
229         changed |= ieee80211_mps_set_sta_local_pm(sta,
230                         NL80211_MESH_POWER_UNKNOWN);
231 
232         return changed;
233 }
234 
235 /**
236  * mesh_plink_deactivate - deactivate mesh peer link
237  *
238  * @sta: mesh peer link to deactivate
239  *
240  * All mesh paths with this peer as next hop will be flushed
241  */
242 u32 mesh_plink_deactivate(struct sta_info *sta)
243 {
244         struct ieee80211_sub_if_data *sdata = sta->sdata;
245         u32 changed;
246 
247         spin_lock_bh(&sta->lock);
248         changed = __mesh_plink_deactivate(sta);
249         sta->reason = WLAN_REASON_MESH_PEER_CANCELED;
250         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
251                             sta->sta.addr, sta->llid, sta->plid,
252                             sta->reason);
253         spin_unlock_bh(&sta->lock);
254 
255         return changed;
256 }
257 
258 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
259                                enum ieee80211_self_protected_actioncode action,
260                                u8 *da, u16 llid, u16 plid, u16 reason)
261 {
262         struct ieee80211_local *local = sdata->local;
263         struct sk_buff *skb;
264         struct ieee80211_tx_info *info;
265         struct ieee80211_mgmt *mgmt;
266         bool include_plid = false;
267         u16 peering_proto = 0;
268         u8 *pos, ie_len = 4;
269         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
270                       sizeof(mgmt->u.action.u.self_prot);
271         int err = -ENOMEM;
272 
273         skb = dev_alloc_skb(local->tx_headroom +
274                             hdr_len +
275                             2 + /* capability info */
276                             2 + /* AID */
277                             2 + 8 + /* supported rates */
278                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
279                             2 + sdata->u.mesh.mesh_id_len +
280                             2 + sizeof(struct ieee80211_meshconf_ie) +
281                             2 + sizeof(struct ieee80211_ht_cap) +
282                             2 + sizeof(struct ieee80211_ht_operation) +
283                             2 + 8 + /* peering IE */
284                             sdata->u.mesh.ie_len);
285         if (!skb)
286                 return err;
287         info = IEEE80211_SKB_CB(skb);
288         skb_reserve(skb, local->tx_headroom);
289         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
290         memset(mgmt, 0, hdr_len);
291         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
292                                           IEEE80211_STYPE_ACTION);
293         memcpy(mgmt->da, da, ETH_ALEN);
294         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
295         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
296         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
297         mgmt->u.action.u.self_prot.action_code = action;
298 
299         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
300                 enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
301 
302                 /* capability info */
303                 pos = skb_put(skb, 2);
304                 memset(pos, 0, 2);
305                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
306                         /* AID */
307                         pos = skb_put(skb, 2);
308                         put_unaligned_le16(plid, pos + 2);
309                 }
310                 if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
311                     ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
312                     mesh_add_rsn_ie(sdata, skb) ||
313                     mesh_add_meshid_ie(sdata, skb) ||
314                     mesh_add_meshconf_ie(sdata, skb))
315                         goto free;
316         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
317                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
318                 if (mesh_add_meshid_ie(sdata, skb))
319                         goto free;
320         }
321 
322         /* Add Mesh Peering Management element */
323         switch (action) {
324         case WLAN_SP_MESH_PEERING_OPEN:
325                 break;
326         case WLAN_SP_MESH_PEERING_CONFIRM:
327                 ie_len += 2;
328                 include_plid = true;
329                 break;
330         case WLAN_SP_MESH_PEERING_CLOSE:
331                 if (plid) {
332                         ie_len += 2;
333                         include_plid = true;
334                 }
335                 ie_len += 2;    /* reason code */
336                 break;
337         default:
338                 err = -EINVAL;
339                 goto free;
340         }
341 
342         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
343                 goto free;
344 
345         pos = skb_put(skb, 2 + ie_len);
346         *pos++ = WLAN_EID_PEER_MGMT;
347         *pos++ = ie_len;
348         memcpy(pos, &peering_proto, 2);
349         pos += 2;
350         put_unaligned_le16(llid, pos);
351         pos += 2;
352         if (include_plid) {
353                 put_unaligned_le16(plid, pos);
354                 pos += 2;
355         }
356         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
357                 put_unaligned_le16(reason, pos);
358                 pos += 2;
359         }
360 
361         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
362                 if (mesh_add_ht_cap_ie(sdata, skb) ||
363                     mesh_add_ht_oper_ie(sdata, skb))
364                         goto free;
365         }
366 
367         if (mesh_add_vendor_ies(sdata, skb))
368                 goto free;
369 
370         ieee80211_tx_skb(sdata, skb);
371         return 0;
372 free:
373         kfree_skb(skb);
374         return err;
375 }
376 
377 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
378                                struct sta_info *sta,
379                                struct ieee802_11_elems *elems, bool insert)
380 {
381         struct ieee80211_local *local = sdata->local;
382         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
383         struct ieee80211_supported_band *sband;
384         u32 rates, basic_rates = 0, changed = 0;
385 
386         sband = local->hw.wiphy->bands[band];
387         rates = ieee80211_sta_get_rates(sdata, elems, band, &basic_rates);
388 
389         spin_lock_bh(&sta->lock);
390         sta->last_rx = jiffies;
391 
392         /* rates and capabilities don't change during peering */
393         if (sta->plink_state == NL80211_PLINK_ESTAB)
394                 goto out;
395 
396         if (sta->sta.supp_rates[band] != rates)
397                 changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
398         sta->sta.supp_rates[band] = rates;
399 
400         if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
401                                               elems->ht_cap_elem, sta))
402                 changed |= IEEE80211_RC_BW_CHANGED;
403 
404         /* HT peer is operating 20MHz-only */
405         if (elems->ht_operation &&
406             !(elems->ht_operation->ht_param &
407               IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
408                 if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
409                         changed |= IEEE80211_RC_BW_CHANGED;
410                 sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
411         }
412 
413         if (insert)
414                 rate_control_rate_init(sta);
415         else
416                 rate_control_rate_update(local, sband, sta, changed);
417 out:
418         spin_unlock_bh(&sta->lock);
419 }
420 
421 static struct sta_info *
422 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
423 {
424         struct sta_info *sta;
425 
426         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
427                 return NULL;
428 
429         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
430         if (!sta)
431                 return NULL;
432 
433         sta->plink_state = NL80211_PLINK_LISTEN;
434 
435         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
436         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
437         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
438 
439         set_sta_flag(sta, WLAN_STA_WME);
440         sta->sta.wme = true;
441 
442         return sta;
443 }
444 
445 static struct sta_info *
446 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
447                     struct ieee802_11_elems *elems)
448 {
449         struct sta_info *sta = NULL;
450 
451         /* Userspace handles station allocation */
452         if (sdata->u.mesh.user_mpm ||
453             sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
454                 cfg80211_notify_new_peer_candidate(sdata->dev, addr,
455                                                    elems->ie_start,
456                                                    elems->total_len,
457                                                    GFP_KERNEL);
458         else
459                 sta = __mesh_sta_info_alloc(sdata, addr);
460 
461         return sta;
462 }
463 
464 /*
465  * mesh_sta_info_get - return mesh sta info entry for @addr.
466  *
467  * @sdata: local meshif
468  * @addr: peer's address
469  * @elems: IEs from beacon or mesh peering frame.
470  *
471  * Return existing or newly allocated sta_info under RCU read lock.
472  * (re)initialize with given IEs.
473  */
474 static struct sta_info *
475 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
476                   u8 *addr, struct ieee802_11_elems *elems) __acquires(RCU)
477 {
478         struct sta_info *sta = NULL;
479 
480         rcu_read_lock();
481         sta = sta_info_get(sdata, addr);
482         if (sta) {
483                 mesh_sta_info_init(sdata, sta, elems, false);
484         } else {
485                 rcu_read_unlock();
486                 /* can't run atomic */
487                 sta = mesh_sta_info_alloc(sdata, addr, elems);
488                 if (!sta) {
489                         rcu_read_lock();
490                         return NULL;
491                 }
492 
493                 mesh_sta_info_init(sdata, sta, elems, true);
494 
495                 if (sta_info_insert_rcu(sta))
496                         return NULL;
497         }
498 
499         return sta;
500 }
501 
502 /*
503  * mesh_neighbour_update - update or initialize new mesh neighbor.
504  *
505  * @sdata: local meshif
506  * @addr: peer's address
507  * @elems: IEs from beacon or mesh peering frame
508  *
509  * Initiates peering if appropriate.
510  */
511 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
512                            u8 *hw_addr,
513                            struct ieee802_11_elems *elems)
514 {
515         struct sta_info *sta;
516         u32 changed = 0;
517 
518         sta = mesh_sta_info_get(sdata, hw_addr, elems);
519         if (!sta)
520                 goto out;
521 
522         if (mesh_peer_accepts_plinks(elems) &&
523             sta->plink_state == NL80211_PLINK_LISTEN &&
524             sdata->u.mesh.accepting_plinks &&
525             sdata->u.mesh.mshcfg.auto_open_plinks &&
526             rssi_threshold_check(sdata, sta))
527                 changed = mesh_plink_open(sta);
528 
529         ieee80211_mps_frame_release(sta, elems);
530 out:
531         rcu_read_unlock();
532         ieee80211_mbss_info_change_notify(sdata, changed);
533 }
534 
535 static void mesh_plink_timer(unsigned long data)
536 {
537         struct sta_info *sta;
538         u16 reason = 0;
539         struct ieee80211_sub_if_data *sdata;
540         struct mesh_config *mshcfg;
541         enum ieee80211_self_protected_actioncode action = 0;
542 
543         /*
544          * This STA is valid because sta_info_destroy() will
545          * del_timer_sync() this timer after having made sure
546          * it cannot be readded (by deleting the plink.)
547          */
548         sta = (struct sta_info *) data;
549 
550         if (sta->sdata->local->quiescing)
551                 return;
552 
553         spin_lock_bh(&sta->lock);
554 
555         /* If a timer fires just before a state transition on another CPU,
556          * we may have already extended the timeout and changed state by the
557          * time we've acquired the lock and arrived  here.  In that case,
558          * skip this timer and wait for the new one.
559          */
560         if (time_before(jiffies, sta->plink_timer.expires)) {
561                 mpl_dbg(sta->sdata,
562                         "Ignoring timer for %pM in state %s (timer adjusted)",
563                         sta->sta.addr, mplstates[sta->plink_state]);
564                 spin_unlock_bh(&sta->lock);
565                 return;
566         }
567 
568         /* del_timer() and handler may race when entering these states */
569         if (sta->plink_state == NL80211_PLINK_LISTEN ||
570             sta->plink_state == NL80211_PLINK_ESTAB) {
571                 mpl_dbg(sta->sdata,
572                         "Ignoring timer for %pM in state %s (timer deleted)",
573                         sta->sta.addr, mplstates[sta->plink_state]);
574                 spin_unlock_bh(&sta->lock);
575                 return;
576         }
577 
578         mpl_dbg(sta->sdata,
579                 "Mesh plink timer for %pM fired on state %s\n",
580                 sta->sta.addr, mplstates[sta->plink_state]);
581         sdata = sta->sdata;
582         mshcfg = &sdata->u.mesh.mshcfg;
583 
584         switch (sta->plink_state) {
585         case NL80211_PLINK_OPN_RCVD:
586         case NL80211_PLINK_OPN_SNT:
587                 /* retry timer */
588                 if (sta->plink_retries < mshcfg->dot11MeshMaxRetries) {
589                         u32 rand;
590                         mpl_dbg(sta->sdata,
591                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
592                                 sta->sta.addr, sta->plink_retries,
593                                 sta->plink_timeout);
594                         get_random_bytes(&rand, sizeof(u32));
595                         sta->plink_timeout = sta->plink_timeout +
596                                              rand % sta->plink_timeout;
597                         ++sta->plink_retries;
598                         mod_plink_timer(sta, sta->plink_timeout);
599                         action = WLAN_SP_MESH_PEERING_OPEN;
600                         break;
601                 }
602                 reason = WLAN_REASON_MESH_MAX_RETRIES;
603                 /* fall through on else */
604         case NL80211_PLINK_CNF_RCVD:
605                 /* confirm timer */
606                 if (!reason)
607                         reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
608                 sta->plink_state = NL80211_PLINK_HOLDING;
609                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
610                 action = WLAN_SP_MESH_PEERING_CLOSE;
611                 break;
612         case NL80211_PLINK_HOLDING:
613                 /* holding timer */
614                 del_timer(&sta->plink_timer);
615                 mesh_plink_fsm_restart(sta);
616                 break;
617         default:
618                 break;
619         }
620         spin_unlock_bh(&sta->lock);
621         if (action)
622                 mesh_plink_frame_tx(sdata, action, sta->sta.addr,
623                                     sta->llid, sta->plid, reason);
624 }
625 
626 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
627 {
628         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
629         sta->plink_timer.data = (unsigned long) sta;
630         sta->plink_timer.function = mesh_plink_timer;
631         sta->plink_timeout = timeout;
632         add_timer(&sta->plink_timer);
633 }
634 
635 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
636                         u16 llid)
637 {
638         struct ieee80211_local *local = sdata->local;
639         bool in_use = false;
640         struct sta_info *sta;
641 
642         rcu_read_lock();
643         list_for_each_entry_rcu(sta, &local->sta_list, list) {
644                 if (!memcmp(&sta->llid, &llid, sizeof(llid))) {
645                         in_use = true;
646                         break;
647                 }
648         }
649         rcu_read_unlock();
650 
651         return in_use;
652 }
653 
654 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
655 {
656         u16 llid;
657 
658         do {
659                 get_random_bytes(&llid, sizeof(llid));
660                 /* for mesh PS we still only have the AID range for TIM bits */
661                 llid = (llid % IEEE80211_MAX_AID) + 1;
662         } while (llid_in_use(sdata, llid));
663 
664         return llid;
665 }
666 
667 u32 mesh_plink_open(struct sta_info *sta)
668 {
669         struct ieee80211_sub_if_data *sdata = sta->sdata;
670         u32 changed;
671 
672         if (!test_sta_flag(sta, WLAN_STA_AUTH))
673                 return 0;
674 
675         spin_lock_bh(&sta->lock);
676         sta->llid = mesh_get_new_llid(sdata);
677         if (sta->plink_state != NL80211_PLINK_LISTEN &&
678             sta->plink_state != NL80211_PLINK_BLOCKED) {
679                 spin_unlock_bh(&sta->lock);
680                 return 0;
681         }
682         sta->plink_state = NL80211_PLINK_OPN_SNT;
683         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
684         spin_unlock_bh(&sta->lock);
685         mpl_dbg(sdata,
686                 "Mesh plink: starting establishment with %pM\n",
687                 sta->sta.addr);
688 
689         /* set the non-peer mode to active during peering */
690         changed = ieee80211_mps_local_status_update(sdata);
691 
692         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
693                             sta->sta.addr, sta->llid, 0, 0);
694         return changed;
695 }
696 
697 u32 mesh_plink_block(struct sta_info *sta)
698 {
699         u32 changed;
700 
701         spin_lock_bh(&sta->lock);
702         changed = __mesh_plink_deactivate(sta);
703         sta->plink_state = NL80211_PLINK_BLOCKED;
704         spin_unlock_bh(&sta->lock);
705 
706         return changed;
707 }
708 
709 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
710                              struct sta_info *sta,
711                              enum plink_event event)
712 {
713         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
714 
715         u16 reason = (event == CLS_ACPT) ?
716                      WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
717 
718         sta->reason = reason;
719         sta->plink_state = NL80211_PLINK_HOLDING;
720         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
721 }
722 
723 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
724                                 struct sta_info *sta)
725 {
726         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
727         u32 changed = 0;
728 
729         del_timer(&sta->plink_timer);
730         sta->plink_state = NL80211_PLINK_ESTAB;
731         changed |= mesh_plink_inc_estab_count(sdata);
732         changed |= mesh_set_ht_prot_mode(sdata);
733         changed |= mesh_set_short_slot_time(sdata);
734         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
735         ieee80211_mps_sta_status_update(sta);
736         changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
737         return changed;
738 }
739 
740 /**
741  * mesh_plink_fsm - step @sta MPM based on @event
742  *
743  * @sdata: interface
744  * @sta: mesh neighbor
745  * @event: peering event
746  *
747  * Return: changed MBSS flags
748  */
749 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
750                           struct sta_info *sta, enum plink_event event)
751 {
752         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
753         enum ieee80211_self_protected_actioncode action = 0;
754         u32 changed = 0;
755 
756         mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
757                 mplstates[sta->plink_state], mplevents[event]);
758 
759         spin_lock_bh(&sta->lock);
760         switch (sta->plink_state) {
761         case NL80211_PLINK_LISTEN:
762                 switch (event) {
763                 case CLS_ACPT:
764                         mesh_plink_fsm_restart(sta);
765                         break;
766                 case OPN_ACPT:
767                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
768                         sta->llid = mesh_get_new_llid(sdata);
769                         mesh_plink_timer_set(sta,
770                                              mshcfg->dot11MeshRetryTimeout);
771 
772                         /* set the non-peer mode to active during peering */
773                         changed |= ieee80211_mps_local_status_update(sdata);
774                         action = WLAN_SP_MESH_PEERING_OPEN;
775                         break;
776                 default:
777                         break;
778                 }
779                 break;
780         case NL80211_PLINK_OPN_SNT:
781                 switch (event) {
782                 case OPN_RJCT:
783                 case CNF_RJCT:
784                 case CLS_ACPT:
785                         mesh_plink_close(sdata, sta, event);
786                         action = WLAN_SP_MESH_PEERING_CLOSE;
787                         break;
788                 case OPN_ACPT:
789                         /* retry timer is left untouched */
790                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
791                         action = WLAN_SP_MESH_PEERING_CONFIRM;
792                         break;
793                 case CNF_ACPT:
794                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
795                         mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
796                         break;
797                 default:
798                         break;
799                 }
800                 break;
801         case NL80211_PLINK_OPN_RCVD:
802                 switch (event) {
803                 case OPN_RJCT:
804                 case CNF_RJCT:
805                 case CLS_ACPT:
806                         mesh_plink_close(sdata, sta, event);
807                         action = WLAN_SP_MESH_PEERING_CLOSE;
808                         break;
809                 case OPN_ACPT:
810                         action = WLAN_SP_MESH_PEERING_CONFIRM;
811                         break;
812                 case CNF_ACPT:
813                         changed |= mesh_plink_establish(sdata, sta);
814                         break;
815                 default:
816                         break;
817                 }
818                 break;
819         case NL80211_PLINK_CNF_RCVD:
820                 switch (event) {
821                 case OPN_RJCT:
822                 case CNF_RJCT:
823                 case CLS_ACPT:
824                         mesh_plink_close(sdata, sta, event);
825                         action = WLAN_SP_MESH_PEERING_CLOSE;
826                         break;
827                 case OPN_ACPT:
828                         changed |= mesh_plink_establish(sdata, sta);
829                         action = WLAN_SP_MESH_PEERING_CONFIRM;
830                         break;
831                 default:
832                         break;
833                 }
834                 break;
835         case NL80211_PLINK_ESTAB:
836                 switch (event) {
837                 case CLS_ACPT:
838                         changed |= __mesh_plink_deactivate(sta);
839                         changed |= mesh_set_ht_prot_mode(sdata);
840                         changed |= mesh_set_short_slot_time(sdata);
841                         mesh_plink_close(sdata, sta, event);
842                         action = WLAN_SP_MESH_PEERING_CLOSE;
843                         break;
844                 case OPN_ACPT:
845                         action = WLAN_SP_MESH_PEERING_CONFIRM;
846                         break;
847                 default:
848                         break;
849                 }
850                 break;
851         case NL80211_PLINK_HOLDING:
852                 switch (event) {
853                 case CLS_ACPT:
854                         del_timer(&sta->plink_timer);
855                         mesh_plink_fsm_restart(sta);
856                         break;
857                 case OPN_ACPT:
858                 case CNF_ACPT:
859                 case OPN_RJCT:
860                 case CNF_RJCT:
861                         action = WLAN_SP_MESH_PEERING_CLOSE;
862                         break;
863                 default:
864                         break;
865                 }
866                 break;
867         default:
868                 /* should not get here, PLINK_BLOCKED is dealt with at the
869                  * beginning of the function
870                  */
871                 break;
872         }
873         spin_unlock_bh(&sta->lock);
874         if (action) {
875                 mesh_plink_frame_tx(sdata, action, sta->sta.addr,
876                                     sta->llid, sta->plid, sta->reason);
877 
878                 /* also send confirm in open case */
879                 if (action == WLAN_SP_MESH_PEERING_OPEN) {
880                         mesh_plink_frame_tx(sdata,
881                                             WLAN_SP_MESH_PEERING_CONFIRM,
882                                             sta->sta.addr, sta->llid,
883                                             sta->plid, 0);
884                 }
885         }
886 
887         return changed;
888 }
889 
890 /*
891  * mesh_plink_get_event - get correct MPM event
892  *
893  * @sdata: interface
894  * @sta: peer, leave NULL if processing a frame from a new suitable peer
895  * @elems: peering management IEs
896  * @ftype: frame type
897  * @llid: peer's peer link ID
898  * @plid: peer's local link ID
899  *
900  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
901  * an error.
902  */
903 static enum plink_event
904 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
905                      struct sta_info *sta,
906                      struct ieee802_11_elems *elems,
907                      enum ieee80211_self_protected_actioncode ftype,
908                      u16 llid, u16 plid)
909 {
910         enum plink_event event = PLINK_UNDEFINED;
911         u8 ie_len = elems->peering_len;
912         bool matches_local;
913 
914         matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
915                          mesh_matches_local(sdata, elems));
916 
917         /* deny open request from non-matching peer */
918         if (!matches_local && !sta) {
919                 event = OPN_RJCT;
920                 goto out;
921         }
922 
923         if (!sta) {
924                 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
925                         mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
926                         goto out;
927                 }
928                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
929                 if (!mesh_plink_free_count(sdata)) {
930                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
931                         goto out;
932                 }
933         } else {
934                 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
935                         mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
936                         goto out;
937                 }
938                 if (sta->plink_state == NL80211_PLINK_BLOCKED)
939                         goto out;
940         }
941 
942         /* new matching peer */
943         if (!sta) {
944                 event = OPN_ACPT;
945                 goto out;
946         }
947 
948         switch (ftype) {
949         case WLAN_SP_MESH_PEERING_OPEN:
950                 if (!matches_local)
951                         event = OPN_RJCT;
952                 if (!mesh_plink_free_count(sdata) ||
953                     (sta->plid && sta->plid != plid))
954                         event = OPN_IGNR;
955                 else
956                         event = OPN_ACPT;
957                 break;
958         case WLAN_SP_MESH_PEERING_CONFIRM:
959                 if (!matches_local)
960                         event = CNF_RJCT;
961                 if (!mesh_plink_free_count(sdata) ||
962                     sta->llid != llid ||
963                     (sta->plid && sta->plid != plid))
964                         event = CNF_IGNR;
965                 else
966                         event = CNF_ACPT;
967                 break;
968         case WLAN_SP_MESH_PEERING_CLOSE:
969                 if (sta->plink_state == NL80211_PLINK_ESTAB)
970                         /* Do not check for llid or plid. This does not
971                          * follow the standard but since multiple plinks
972                          * per sta are not supported, it is necessary in
973                          * order to avoid a livelock when MP A sees an
974                          * establish peer link to MP B but MP B does not
975                          * see it. This can be caused by a timeout in
976                          * B's peer link establishment or B beign
977                          * restarted.
978                          */
979                         event = CLS_ACPT;
980                 else if (sta->plid != plid)
981                         event = CLS_IGNR;
982                 else if (ie_len == 8 && sta->llid != llid)
983                         event = CLS_IGNR;
984                 else
985                         event = CLS_ACPT;
986                 break;
987         default:
988                 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
989                 break;
990         }
991 
992 out:
993         return event;
994 }
995 
996 static void
997 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
998                          struct ieee80211_mgmt *mgmt,
999                          struct ieee802_11_elems *elems)
1000 {
1001 
1002         struct sta_info *sta;
1003         enum plink_event event;
1004         enum ieee80211_self_protected_actioncode ftype;
1005         u32 changed = 0;
1006         u8 ie_len = elems->peering_len;
1007         __le16 _plid, _llid;
1008         u16 plid, llid = 0;
1009 
1010         if (!elems->peering) {
1011                 mpl_dbg(sdata,
1012                         "Mesh plink: missing necessary peer link ie\n");
1013                 return;
1014         }
1015 
1016         if (elems->rsn_len &&
1017             sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1018                 mpl_dbg(sdata,
1019                         "Mesh plink: can't establish link with secure peer\n");
1020                 return;
1021         }
1022 
1023         ftype = mgmt->u.action.u.self_prot.action_code;
1024         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1025             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1026             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1027                                                         && ie_len != 8)) {
1028                 mpl_dbg(sdata,
1029                         "Mesh plink: incorrect plink ie length %d %d\n",
1030                         ftype, ie_len);
1031                 return;
1032         }
1033 
1034         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1035             (!elems->mesh_id || !elems->mesh_config)) {
1036                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1037                 return;
1038         }
1039         /* Note the lines below are correct, the llid in the frame is the plid
1040          * from the point of view of this host.
1041          */
1042         memcpy(&_plid, PLINK_GET_LLID(elems->peering), sizeof(__le16));
1043         plid = le16_to_cpu(_plid);
1044         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1045             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8)) {
1046                 memcpy(&_llid, PLINK_GET_PLID(elems->peering), sizeof(__le16));
1047                 llid = le16_to_cpu(_llid);
1048         }
1049 
1050         /* WARNING: Only for sta pointer, is dropped & re-acquired */
1051         rcu_read_lock();
1052 
1053         sta = sta_info_get(sdata, mgmt->sa);
1054 
1055         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1056             !rssi_threshold_check(sdata, sta)) {
1057                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1058                         mgmt->sa);
1059                 goto unlock_rcu;
1060         }
1061 
1062         /* Now we will figure out the appropriate event... */
1063         event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1064 
1065         if (event == OPN_ACPT) {
1066                 rcu_read_unlock();
1067                 /* allocate sta entry if necessary and update info */
1068                 sta = mesh_sta_info_get(sdata, mgmt->sa, elems);
1069                 if (!sta) {
1070                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1071                         goto unlock_rcu;
1072                 }
1073                 sta->plid = plid;
1074         } else if (!sta && event == OPN_RJCT) {
1075                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
1076                                     mgmt->sa, 0, plid,
1077                                     WLAN_REASON_MESH_CONFIG);
1078                 goto unlock_rcu;
1079         } else if (!sta || event == PLINK_UNDEFINED) {
1080                 /* something went wrong */
1081                 goto unlock_rcu;
1082         }
1083 
1084         /* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1085         if (!sta->plid && event == CNF_ACPT)
1086                 sta->plid = plid;
1087 
1088         changed |= mesh_plink_fsm(sdata, sta, event);
1089 
1090 unlock_rcu:
1091         rcu_read_unlock();
1092 
1093         if (changed)
1094                 ieee80211_mbss_info_change_notify(sdata, changed);
1095 }
1096 
1097 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1098                          struct ieee80211_mgmt *mgmt, size_t len,
1099                          struct ieee80211_rx_status *rx_status)
1100 {
1101         struct ieee802_11_elems elems;
1102         size_t baselen;
1103         u8 *baseaddr;
1104 
1105         /* need action_code, aux */
1106         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1107                 return;
1108 
1109         if (sdata->u.mesh.user_mpm)
1110                 /* userspace must register for these */
1111                 return;
1112 
1113         if (is_multicast_ether_addr(mgmt->da)) {
1114                 mpl_dbg(sdata,
1115                         "Mesh plink: ignore frame from multicast address\n");
1116                 return;
1117         }
1118 
1119         baseaddr = mgmt->u.action.u.self_prot.variable;
1120         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1121         if (mgmt->u.action.u.self_prot.action_code ==
1122                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
1123                 baseaddr += 4;
1124                 baselen += 4;
1125         }
1126         ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems);
1127         mesh_process_plink_frame(sdata, mgmt, &elems);
1128 }
1129 

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