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 <linux/rculist.h>
13
14 #include "ieee80211_i.h"
15 #include "rate.h"
16 #include "mesh.h"
17
18 #define PLINK_CNF_AID(mgmt) ((mgmt)->u.action.u.self_prot.variable + 2)
19 #define PLINK_GET_LLID(p) (p + 2)
20 #define PLINK_GET_PLID(p) (p + 4)
21
22 #define mod_plink_timer(s, t) (mod_timer(&s->mesh->plink_timer, \
23 jiffies + msecs_to_jiffies(t)))
24
25 enum plink_event {
26 PLINK_UNDEFINED,
27 OPN_ACPT,
28 OPN_RJCT,
29 OPN_IGNR,
30 CNF_ACPT,
31 CNF_RJCT,
32 CNF_IGNR,
33 CLS_ACPT,
34 CLS_IGNR
35 };
36
37 static const char * const mplstates[] = {
38 [NL80211_PLINK_LISTEN] = "LISTEN",
39 [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
40 [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
41 [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
42 [NL80211_PLINK_ESTAB] = "ESTAB",
43 [NL80211_PLINK_HOLDING] = "HOLDING",
44 [NL80211_PLINK_BLOCKED] = "BLOCKED"
45 };
46
47 static const char * const mplevents[] = {
48 [PLINK_UNDEFINED] = "NONE",
49 [OPN_ACPT] = "OPN_ACPT",
50 [OPN_RJCT] = "OPN_RJCT",
51 [OPN_IGNR] = "OPN_IGNR",
52 [CNF_ACPT] = "CNF_ACPT",
53 [CNF_RJCT] = "CNF_RJCT",
54 [CNF_IGNR] = "CNF_IGNR",
55 [CLS_ACPT] = "CLS_ACPT",
56 [CLS_IGNR] = "CLS_IGNR"
57 };
58
59 /* 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)60 static bool rssi_threshold_check(struct ieee80211_sub_if_data *sdata,
61 struct sta_info *sta)
62 {
63 s32 rssi_threshold = sdata->u.mesh.mshcfg.rssi_threshold;
64 return rssi_threshold == 0 ||
65 (sta &&
66 (s8)-ewma_signal_read(&sta->rx_stats_avg.signal) >
67 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->mesh->plink_lock
76 */
mesh_plink_fsm_restart(struct sta_info * sta)77 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
78 {
79 lockdep_assert_held(&sta->mesh->plink_lock);
80 sta->mesh->plink_state = NL80211_PLINK_LISTEN;
81 sta->mesh->llid = sta->mesh->plid = sta->mesh->reason = 0;
82 sta->mesh->plink_retries = 0;
83 }
84
85 /*
86 * mesh_set_short_slot_time - enable / disable ERP short slot time.
87 *
88 * The standard indirectly mandates mesh STAs to turn off short slot time by
89 * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
90 * can't be sneaky about it. Enable short slot time if all mesh STAs in the
91 * MBSS support ERP rates.
92 *
93 * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
94 */
mesh_set_short_slot_time(struct ieee80211_sub_if_data * sdata)95 static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
96 {
97 struct ieee80211_local *local = sdata->local;
98 struct ieee80211_supported_band *sband;
99 struct sta_info *sta;
100 u32 erp_rates = 0, changed = 0;
101 int i;
102 bool short_slot = false;
103
104 sband = ieee80211_get_sband(sdata);
105 if (!sband)
106 return changed;
107
108 if (sband->band == NL80211_BAND_5GHZ) {
109 /* (IEEE 802.11-2012 19.4.5) */
110 short_slot = true;
111 goto out;
112 } else if (sband->band != NL80211_BAND_2GHZ) {
113 goto out;
114 }
115
116 for (i = 0; i < sband->n_bitrates; i++)
117 if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
118 erp_rates |= BIT(i);
119
120 if (!erp_rates)
121 goto out;
122
123 rcu_read_lock();
124 list_for_each_entry_rcu(sta, &local->sta_list, list) {
125 if (sdata != sta->sdata ||
126 sta->mesh->plink_state != NL80211_PLINK_ESTAB)
127 continue;
128
129 short_slot = false;
130 if (erp_rates & sta->sta.supp_rates[sband->band])
131 short_slot = true;
132 else
133 break;
134 }
135 rcu_read_unlock();
136
137 out:
138 if (sdata->vif.bss_conf.use_short_slot != short_slot) {
139 sdata->vif.bss_conf.use_short_slot = short_slot;
140 changed = BSS_CHANGED_ERP_SLOT;
141 mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
142 sdata->vif.addr, short_slot);
143 }
144 return changed;
145 }
146
147 /**
148 * mesh_set_ht_prot_mode - set correct HT protection mode
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 atleast one
155 * HT20 peer is present. Otherwise no-protection mode is selected.
156 */
mesh_set_ht_prot_mode(struct ieee80211_sub_if_data * sdata)157 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
158 {
159 struct ieee80211_local *local = sdata->local;
160 struct sta_info *sta;
161 u16 ht_opmode;
162 bool non_ht_sta = false, ht20_sta = false;
163
164 switch (sdata->vif.bss_conf.chandef.width) {
165 case NL80211_CHAN_WIDTH_20_NOHT:
166 case NL80211_CHAN_WIDTH_5:
167 case NL80211_CHAN_WIDTH_10:
168 return 0;
169 default:
170 break;
171 }
172
173 rcu_read_lock();
174 list_for_each_entry_rcu(sta, &local->sta_list, list) {
175 if (sdata != sta->sdata ||
176 sta->mesh->plink_state != NL80211_PLINK_ESTAB)
177 continue;
178
179 if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
180 continue;
181
182 if (!sta->sta.ht_cap.ht_supported) {
183 mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
184 sta->sta.addr);
185 non_ht_sta = true;
186 break;
187 }
188
189 mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
190 ht20_sta = true;
191 }
192 rcu_read_unlock();
193
194 if (non_ht_sta)
195 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
196 else if (ht20_sta &&
197 sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
198 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
199 else
200 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
201
202 if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
203 return 0;
204
205 sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
206 sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
207 mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
208 return BSS_CHANGED_HT;
209 }
210
mesh_plink_frame_tx(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum ieee80211_self_protected_actioncode action,u8 * da,u16 llid,u16 plid,u16 reason)211 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
212 struct sta_info *sta,
213 enum ieee80211_self_protected_actioncode action,
214 u8 *da, u16 llid, u16 plid, u16 reason)
215 {
216 struct ieee80211_local *local = sdata->local;
217 struct sk_buff *skb;
218 struct ieee80211_tx_info *info;
219 struct ieee80211_mgmt *mgmt;
220 bool include_plid = false;
221 u16 peering_proto = 0;
222 u8 *pos, ie_len = 4;
223 int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.self_prot);
224 int err = -ENOMEM;
225
226 skb = dev_alloc_skb(local->tx_headroom +
227 hdr_len +
228 2 + /* capability info */
229 2 + /* AID */
230 2 + 8 + /* supported rates */
231 2 + (IEEE80211_MAX_SUPP_RATES - 8) +
232 2 + sdata->u.mesh.mesh_id_len +
233 2 + sizeof(struct ieee80211_meshconf_ie) +
234 2 + sizeof(struct ieee80211_ht_cap) +
235 2 + sizeof(struct ieee80211_ht_operation) +
236 2 + sizeof(struct ieee80211_vht_cap) +
237 2 + sizeof(struct ieee80211_vht_operation) +
238 2 + 8 + /* peering IE */
239 sdata->u.mesh.ie_len);
240 if (!skb)
241 return err;
242 info = IEEE80211_SKB_CB(skb);
243 skb_reserve(skb, local->tx_headroom);
244 mgmt = skb_put_zero(skb, hdr_len);
245 mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
246 IEEE80211_STYPE_ACTION);
247 memcpy(mgmt->da, da, ETH_ALEN);
248 memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
249 memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
250 mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
251 mgmt->u.action.u.self_prot.action_code = action;
252
253 if (action != WLAN_SP_MESH_PEERING_CLOSE) {
254 struct ieee80211_supported_band *sband;
255 enum nl80211_band band;
256
257 sband = ieee80211_get_sband(sdata);
258 if (!sband) {
259 err = -EINVAL;
260 goto free;
261 }
262 band = sband->band;
263
264 /* capability info */
265 pos = skb_put_zero(skb, 2);
266 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
267 /* AID */
268 pos = skb_put(skb, 2);
269 put_unaligned_le16(sta->sta.aid, pos);
270 }
271 if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
272 ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
273 mesh_add_rsn_ie(sdata, skb) ||
274 mesh_add_meshid_ie(sdata, skb) ||
275 mesh_add_meshconf_ie(sdata, skb))
276 goto free;
277 } else { /* WLAN_SP_MESH_PEERING_CLOSE */
278 info->flags |= IEEE80211_TX_CTL_NO_ACK;
279 if (mesh_add_meshid_ie(sdata, skb))
280 goto free;
281 }
282
283 /* Add Mesh Peering Management element */
284 switch (action) {
285 case WLAN_SP_MESH_PEERING_OPEN:
286 break;
287 case WLAN_SP_MESH_PEERING_CONFIRM:
288 ie_len += 2;
289 include_plid = true;
290 break;
291 case WLAN_SP_MESH_PEERING_CLOSE:
292 if (plid) {
293 ie_len += 2;
294 include_plid = true;
295 }
296 ie_len += 2; /* reason code */
297 break;
298 default:
299 err = -EINVAL;
300 goto free;
301 }
302
303 if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
304 goto free;
305
306 pos = skb_put(skb, 2 + ie_len);
307 *pos++ = WLAN_EID_PEER_MGMT;
308 *pos++ = ie_len;
309 memcpy(pos, &peering_proto, 2);
310 pos += 2;
311 put_unaligned_le16(llid, pos);
312 pos += 2;
313 if (include_plid) {
314 put_unaligned_le16(plid, pos);
315 pos += 2;
316 }
317 if (action == WLAN_SP_MESH_PEERING_CLOSE) {
318 put_unaligned_le16(reason, pos);
319 pos += 2;
320 }
321
322 if (action != WLAN_SP_MESH_PEERING_CLOSE) {
323 if (mesh_add_ht_cap_ie(sdata, skb) ||
324 mesh_add_ht_oper_ie(sdata, skb) ||
325 mesh_add_vht_cap_ie(sdata, skb) ||
326 mesh_add_vht_oper_ie(sdata, skb))
327 goto free;
328 }
329
330 if (mesh_add_vendor_ies(sdata, skb))
331 goto free;
332
333 ieee80211_tx_skb(sdata, skb);
334 return 0;
335 free:
336 kfree_skb(skb);
337 return err;
338 }
339
340 /**
341 * __mesh_plink_deactivate - deactivate mesh peer link
342 *
343 * @sta: mesh peer link to deactivate
344 *
345 * Mesh paths with this peer as next hop should be flushed
346 * by the caller outside of plink_lock.
347 *
348 * Returns beacon changed flag if the beacon content changed.
349 *
350 * Locking: the caller must hold sta->mesh->plink_lock
351 */
__mesh_plink_deactivate(struct sta_info * sta)352 static u32 __mesh_plink_deactivate(struct sta_info *sta)
353 {
354 struct ieee80211_sub_if_data *sdata = sta->sdata;
355 u32 changed = 0;
356
357 lockdep_assert_held(&sta->mesh->plink_lock);
358
359 if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
360 changed = mesh_plink_dec_estab_count(sdata);
361 sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
362
363 ieee80211_mps_sta_status_update(sta);
364 changed |= ieee80211_mps_set_sta_local_pm(sta,
365 NL80211_MESH_POWER_UNKNOWN);
366
367 return changed;
368 }
369
370 /**
371 * mesh_plink_deactivate - deactivate mesh peer link
372 *
373 * @sta: mesh peer link to deactivate
374 *
375 * All mesh paths with this peer as next hop will be flushed
376 */
mesh_plink_deactivate(struct sta_info * sta)377 u32 mesh_plink_deactivate(struct sta_info *sta)
378 {
379 struct ieee80211_sub_if_data *sdata = sta->sdata;
380 u32 changed;
381
382 spin_lock_bh(&sta->mesh->plink_lock);
383 changed = __mesh_plink_deactivate(sta);
384
385 if (!sdata->u.mesh.user_mpm) {
386 sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
387 mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
388 sta->sta.addr, sta->mesh->llid,
389 sta->mesh->plid, sta->mesh->reason);
390 }
391 spin_unlock_bh(&sta->mesh->plink_lock);
392 if (!sdata->u.mesh.user_mpm)
393 del_timer_sync(&sta->mesh->plink_timer);
394 mesh_path_flush_by_nexthop(sta);
395
396 /* make sure no readers can access nexthop sta from here on */
397 synchronize_net();
398
399 return changed;
400 }
401
mesh_sta_info_init(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,struct ieee802_11_elems * elems)402 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
403 struct sta_info *sta,
404 struct ieee802_11_elems *elems)
405 {
406 struct ieee80211_local *local = sdata->local;
407 struct ieee80211_supported_band *sband;
408 u32 rates, basic_rates = 0, changed = 0;
409 enum ieee80211_sta_rx_bandwidth bw = sta->sta.bandwidth;
410
411 sband = ieee80211_get_sband(sdata);
412 if (!sband)
413 return;
414
415 rates = ieee80211_sta_get_rates(sdata, elems, sband->band,
416 &basic_rates);
417
418 spin_lock_bh(&sta->mesh->plink_lock);
419 sta->rx_stats.last_rx = jiffies;
420
421 /* rates and capabilities don't change during peering */
422 if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
423 sta->mesh->processed_beacon)
424 goto out;
425 sta->mesh->processed_beacon = true;
426
427 if (sta->sta.supp_rates[sband->band] != rates)
428 changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
429 sta->sta.supp_rates[sband->band] = rates;
430
431 if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
432 elems->ht_cap_elem, sta))
433 changed |= IEEE80211_RC_BW_CHANGED;
434
435 ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
436 elems->vht_cap_elem, sta);
437
438 if (bw != sta->sta.bandwidth)
439 changed |= IEEE80211_RC_BW_CHANGED;
440
441 /* HT peer is operating 20MHz-only */
442 if (elems->ht_operation &&
443 !(elems->ht_operation->ht_param &
444 IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
445 if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
446 changed |= IEEE80211_RC_BW_CHANGED;
447 sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
448 }
449
450 if (!test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
451 rate_control_rate_init(sta);
452 else
453 rate_control_rate_update(local, sband, sta, changed);
454 out:
455 spin_unlock_bh(&sta->mesh->plink_lock);
456 }
457
mesh_allocate_aid(struct ieee80211_sub_if_data * sdata)458 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
459 {
460 struct sta_info *sta;
461 unsigned long *aid_map;
462 int aid;
463
464 aid_map = kcalloc(BITS_TO_LONGS(IEEE80211_MAX_AID + 1),
465 sizeof(*aid_map), GFP_KERNEL);
466 if (!aid_map)
467 return -ENOMEM;
468
469 /* reserve aid 0 for mcast indication */
470 __set_bit(0, aid_map);
471
472 rcu_read_lock();
473 list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
474 __set_bit(sta->sta.aid, aid_map);
475 rcu_read_unlock();
476
477 aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
478 kfree(aid_map);
479
480 if (aid > IEEE80211_MAX_AID)
481 return -ENOBUFS;
482
483 return aid;
484 }
485
486 static struct sta_info *
__mesh_sta_info_alloc(struct ieee80211_sub_if_data * sdata,u8 * hw_addr)487 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
488 {
489 struct sta_info *sta;
490 int aid;
491
492 if (sdata->local->num_sta >= MESH_MAX_PLINKS)
493 return NULL;
494
495 aid = mesh_allocate_aid(sdata);
496 if (aid < 0)
497 return NULL;
498
499 sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
500 if (!sta)
501 return NULL;
502
503 sta->mesh->plink_state = NL80211_PLINK_LISTEN;
504 sta->sta.wme = true;
505 sta->sta.aid = aid;
506
507 sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
508 sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
509 sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
510
511 return sta;
512 }
513
514 static struct sta_info *
mesh_sta_info_alloc(struct ieee80211_sub_if_data * sdata,u8 * addr,struct ieee802_11_elems * elems)515 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
516 struct ieee802_11_elems *elems)
517 {
518 struct sta_info *sta = NULL;
519
520 /* Userspace handles station allocation */
521 if (sdata->u.mesh.user_mpm ||
522 sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
523 if (mesh_peer_accepts_plinks(elems) &&
524 mesh_plink_availables(sdata))
525 cfg80211_notify_new_peer_candidate(sdata->dev, addr,
526 elems->ie_start,
527 elems->total_len,
528 GFP_KERNEL);
529 } else
530 sta = __mesh_sta_info_alloc(sdata, addr);
531
532 return sta;
533 }
534
535 /*
536 * mesh_sta_info_get - return mesh sta info entry for @addr.
537 *
538 * @sdata: local meshif
539 * @addr: peer's address
540 * @elems: IEs from beacon or mesh peering frame.
541 *
542 * Return existing or newly allocated sta_info under RCU read lock.
543 * (re)initialize with given IEs.
544 */
545 static struct sta_info *
mesh_sta_info_get(struct ieee80211_sub_if_data * sdata,u8 * addr,struct ieee802_11_elems * elems)546 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
547 u8 *addr, struct ieee802_11_elems *elems) __acquires(RCU)
548 {
549 struct sta_info *sta = NULL;
550
551 rcu_read_lock();
552 sta = sta_info_get(sdata, addr);
553 if (sta) {
554 mesh_sta_info_init(sdata, sta, elems);
555 } else {
556 rcu_read_unlock();
557 /* can't run atomic */
558 sta = mesh_sta_info_alloc(sdata, addr, elems);
559 if (!sta) {
560 rcu_read_lock();
561 return NULL;
562 }
563
564 mesh_sta_info_init(sdata, sta, elems);
565
566 if (sta_info_insert_rcu(sta))
567 return NULL;
568 }
569
570 return sta;
571 }
572
573 /*
574 * mesh_neighbour_update - update or initialize new mesh neighbor.
575 *
576 * @sdata: local meshif
577 * @addr: peer's address
578 * @elems: IEs from beacon or mesh peering frame
579 *
580 * Initiates peering if appropriate.
581 */
mesh_neighbour_update(struct ieee80211_sub_if_data * sdata,u8 * hw_addr,struct ieee802_11_elems * elems)582 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
583 u8 *hw_addr,
584 struct ieee802_11_elems *elems)
585 {
586 struct sta_info *sta;
587 u32 changed = 0;
588
589 sta = mesh_sta_info_get(sdata, hw_addr, elems);
590 if (!sta)
591 goto out;
592
593 if (mesh_peer_accepts_plinks(elems) &&
594 sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
595 sdata->u.mesh.accepting_plinks &&
596 sdata->u.mesh.mshcfg.auto_open_plinks &&
597 rssi_threshold_check(sdata, sta))
598 changed = mesh_plink_open(sta);
599
600 ieee80211_mps_frame_release(sta, elems);
601 out:
602 rcu_read_unlock();
603 ieee80211_mbss_info_change_notify(sdata, changed);
604 }
605
mesh_plink_timer(struct timer_list * t)606 void mesh_plink_timer(struct timer_list *t)
607 {
608 struct mesh_sta *mesh = from_timer(mesh, t, plink_timer);
609 struct sta_info *sta;
610 u16 reason = 0;
611 struct ieee80211_sub_if_data *sdata;
612 struct mesh_config *mshcfg;
613 enum ieee80211_self_protected_actioncode action = 0;
614
615 /*
616 * This STA is valid because sta_info_destroy() will
617 * del_timer_sync() this timer after having made sure
618 * it cannot be readded (by deleting the plink.)
619 */
620 sta = mesh->plink_sta;
621
622 if (sta->sdata->local->quiescing)
623 return;
624
625 spin_lock_bh(&sta->mesh->plink_lock);
626
627 /* If a timer fires just before a state transition on another CPU,
628 * we may have already extended the timeout and changed state by the
629 * time we've acquired the lock and arrived here. In that case,
630 * skip this timer and wait for the new one.
631 */
632 if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
633 mpl_dbg(sta->sdata,
634 "Ignoring timer for %pM in state %s (timer adjusted)",
635 sta->sta.addr, mplstates[sta->mesh->plink_state]);
636 spin_unlock_bh(&sta->mesh->plink_lock);
637 return;
638 }
639
640 /* del_timer() and handler may race when entering these states */
641 if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
642 sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
643 mpl_dbg(sta->sdata,
644 "Ignoring timer for %pM in state %s (timer deleted)",
645 sta->sta.addr, mplstates[sta->mesh->plink_state]);
646 spin_unlock_bh(&sta->mesh->plink_lock);
647 return;
648 }
649
650 mpl_dbg(sta->sdata,
651 "Mesh plink timer for %pM fired on state %s\n",
652 sta->sta.addr, mplstates[sta->mesh->plink_state]);
653 sdata = sta->sdata;
654 mshcfg = &sdata->u.mesh.mshcfg;
655
656 switch (sta->mesh->plink_state) {
657 case NL80211_PLINK_OPN_RCVD:
658 case NL80211_PLINK_OPN_SNT:
659 /* retry timer */
660 if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
661 u32 rand;
662 mpl_dbg(sta->sdata,
663 "Mesh plink for %pM (retry, timeout): %d %d\n",
664 sta->sta.addr, sta->mesh->plink_retries,
665 sta->mesh->plink_timeout);
666 get_random_bytes(&rand, sizeof(u32));
667 sta->mesh->plink_timeout = sta->mesh->plink_timeout +
668 rand % sta->mesh->plink_timeout;
669 ++sta->mesh->plink_retries;
670 mod_plink_timer(sta, sta->mesh->plink_timeout);
671 action = WLAN_SP_MESH_PEERING_OPEN;
672 break;
673 }
674 reason = WLAN_REASON_MESH_MAX_RETRIES;
675 /* fall through */
676 case NL80211_PLINK_CNF_RCVD:
677 /* confirm timer */
678 if (!reason)
679 reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
680 sta->mesh->plink_state = NL80211_PLINK_HOLDING;
681 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
682 action = WLAN_SP_MESH_PEERING_CLOSE;
683 break;
684 case NL80211_PLINK_HOLDING:
685 /* holding timer */
686 del_timer(&sta->mesh->plink_timer);
687 mesh_plink_fsm_restart(sta);
688 break;
689 default:
690 break;
691 }
692 spin_unlock_bh(&sta->mesh->plink_lock);
693 if (action)
694 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
695 sta->mesh->llid, sta->mesh->plid, reason);
696 }
697
mesh_plink_timer_set(struct sta_info * sta,u32 timeout)698 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
699 {
700 sta->mesh->plink_timeout = timeout;
701 mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
702 }
703
llid_in_use(struct ieee80211_sub_if_data * sdata,u16 llid)704 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
705 u16 llid)
706 {
707 struct ieee80211_local *local = sdata->local;
708 bool in_use = false;
709 struct sta_info *sta;
710
711 rcu_read_lock();
712 list_for_each_entry_rcu(sta, &local->sta_list, list) {
713 if (sdata != sta->sdata)
714 continue;
715
716 if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
717 in_use = true;
718 break;
719 }
720 }
721 rcu_read_unlock();
722
723 return in_use;
724 }
725
mesh_get_new_llid(struct ieee80211_sub_if_data * sdata)726 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
727 {
728 u16 llid;
729
730 do {
731 get_random_bytes(&llid, sizeof(llid));
732 } while (llid_in_use(sdata, llid));
733
734 return llid;
735 }
736
mesh_plink_open(struct sta_info * sta)737 u32 mesh_plink_open(struct sta_info *sta)
738 {
739 struct ieee80211_sub_if_data *sdata = sta->sdata;
740 u32 changed;
741
742 if (!test_sta_flag(sta, WLAN_STA_AUTH))
743 return 0;
744
745 spin_lock_bh(&sta->mesh->plink_lock);
746 sta->mesh->llid = mesh_get_new_llid(sdata);
747 if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
748 sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
749 spin_unlock_bh(&sta->mesh->plink_lock);
750 return 0;
751 }
752 sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
753 mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
754 spin_unlock_bh(&sta->mesh->plink_lock);
755 mpl_dbg(sdata,
756 "Mesh plink: starting establishment with %pM\n",
757 sta->sta.addr);
758
759 /* set the non-peer mode to active during peering */
760 changed = ieee80211_mps_local_status_update(sdata);
761
762 mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
763 sta->sta.addr, sta->mesh->llid, 0, 0);
764 return changed;
765 }
766
mesh_plink_block(struct sta_info * sta)767 u32 mesh_plink_block(struct sta_info *sta)
768 {
769 u32 changed;
770
771 spin_lock_bh(&sta->mesh->plink_lock);
772 changed = __mesh_plink_deactivate(sta);
773 sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
774 spin_unlock_bh(&sta->mesh->plink_lock);
775 mesh_path_flush_by_nexthop(sta);
776
777 return changed;
778 }
779
mesh_plink_close(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum plink_event event)780 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
781 struct sta_info *sta,
782 enum plink_event event)
783 {
784 struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
785 u16 reason = (event == CLS_ACPT) ?
786 WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
787
788 sta->mesh->reason = reason;
789 sta->mesh->plink_state = NL80211_PLINK_HOLDING;
790 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
791 }
792
mesh_plink_establish(struct ieee80211_sub_if_data * sdata,struct sta_info * sta)793 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
794 struct sta_info *sta)
795 {
796 struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
797 u32 changed = 0;
798
799 del_timer(&sta->mesh->plink_timer);
800 sta->mesh->plink_state = NL80211_PLINK_ESTAB;
801 changed |= mesh_plink_inc_estab_count(sdata);
802 changed |= mesh_set_ht_prot_mode(sdata);
803 changed |= mesh_set_short_slot_time(sdata);
804 mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
805 ieee80211_mps_sta_status_update(sta);
806 changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
807 return changed;
808 }
809
810 /**
811 * mesh_plink_fsm - step @sta MPM based on @event
812 *
813 * @sdata: interface
814 * @sta: mesh neighbor
815 * @event: peering event
816 *
817 * Return: changed MBSS flags
818 */
mesh_plink_fsm(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,enum plink_event event)819 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
820 struct sta_info *sta, enum plink_event event)
821 {
822 struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
823 enum ieee80211_self_protected_actioncode action = 0;
824 u32 changed = 0;
825 bool flush = false;
826
827 mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
828 mplstates[sta->mesh->plink_state], mplevents[event]);
829
830 spin_lock_bh(&sta->mesh->plink_lock);
831 switch (sta->mesh->plink_state) {
832 case NL80211_PLINK_LISTEN:
833 switch (event) {
834 case CLS_ACPT:
835 mesh_plink_fsm_restart(sta);
836 break;
837 case OPN_ACPT:
838 sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
839 sta->mesh->llid = mesh_get_new_llid(sdata);
840 mesh_plink_timer_set(sta,
841 mshcfg->dot11MeshRetryTimeout);
842
843 /* set the non-peer mode to active during peering */
844 changed |= ieee80211_mps_local_status_update(sdata);
845 action = WLAN_SP_MESH_PEERING_OPEN;
846 break;
847 default:
848 break;
849 }
850 break;
851 case NL80211_PLINK_OPN_SNT:
852 switch (event) {
853 case OPN_RJCT:
854 case CNF_RJCT:
855 case CLS_ACPT:
856 mesh_plink_close(sdata, sta, event);
857 action = WLAN_SP_MESH_PEERING_CLOSE;
858 break;
859 case OPN_ACPT:
860 /* retry timer is left untouched */
861 sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
862 action = WLAN_SP_MESH_PEERING_CONFIRM;
863 break;
864 case CNF_ACPT:
865 sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
866 mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
867 break;
868 default:
869 break;
870 }
871 break;
872 case NL80211_PLINK_OPN_RCVD:
873 switch (event) {
874 case OPN_RJCT:
875 case CNF_RJCT:
876 case CLS_ACPT:
877 mesh_plink_close(sdata, sta, event);
878 action = WLAN_SP_MESH_PEERING_CLOSE;
879 break;
880 case OPN_ACPT:
881 action = WLAN_SP_MESH_PEERING_CONFIRM;
882 break;
883 case CNF_ACPT:
884 changed |= mesh_plink_establish(sdata, sta);
885 break;
886 default:
887 break;
888 }
889 break;
890 case NL80211_PLINK_CNF_RCVD:
891 switch (event) {
892 case OPN_RJCT:
893 case CNF_RJCT:
894 case CLS_ACPT:
895 mesh_plink_close(sdata, sta, event);
896 action = WLAN_SP_MESH_PEERING_CLOSE;
897 break;
898 case OPN_ACPT:
899 changed |= mesh_plink_establish(sdata, sta);
900 action = WLAN_SP_MESH_PEERING_CONFIRM;
901 break;
902 default:
903 break;
904 }
905 break;
906 case NL80211_PLINK_ESTAB:
907 switch (event) {
908 case CLS_ACPT:
909 changed |= __mesh_plink_deactivate(sta);
910 changed |= mesh_set_ht_prot_mode(sdata);
911 changed |= mesh_set_short_slot_time(sdata);
912 mesh_plink_close(sdata, sta, event);
913 action = WLAN_SP_MESH_PEERING_CLOSE;
914 flush = true;
915 break;
916 case OPN_ACPT:
917 action = WLAN_SP_MESH_PEERING_CONFIRM;
918 break;
919 default:
920 break;
921 }
922 break;
923 case NL80211_PLINK_HOLDING:
924 switch (event) {
925 case CLS_ACPT:
926 del_timer(&sta->mesh->plink_timer);
927 mesh_plink_fsm_restart(sta);
928 break;
929 case OPN_ACPT:
930 case CNF_ACPT:
931 case OPN_RJCT:
932 case CNF_RJCT:
933 action = WLAN_SP_MESH_PEERING_CLOSE;
934 break;
935 default:
936 break;
937 }
938 break;
939 default:
940 /* should not get here, PLINK_BLOCKED is dealt with at the
941 * beginning of the function
942 */
943 break;
944 }
945 spin_unlock_bh(&sta->mesh->plink_lock);
946 if (flush)
947 mesh_path_flush_by_nexthop(sta);
948 if (action) {
949 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
950 sta->mesh->llid, sta->mesh->plid,
951 sta->mesh->reason);
952
953 /* also send confirm in open case */
954 if (action == WLAN_SP_MESH_PEERING_OPEN) {
955 mesh_plink_frame_tx(sdata, sta,
956 WLAN_SP_MESH_PEERING_CONFIRM,
957 sta->sta.addr, sta->mesh->llid,
958 sta->mesh->plid, 0);
959 }
960 }
961
962 return changed;
963 }
964
965 /*
966 * mesh_plink_get_event - get correct MPM event
967 *
968 * @sdata: interface
969 * @sta: peer, leave NULL if processing a frame from a new suitable peer
970 * @elems: peering management IEs
971 * @ftype: frame type
972 * @llid: peer's peer link ID
973 * @plid: peer's local link ID
974 *
975 * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
976 * an error.
977 */
978 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)979 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
980 struct sta_info *sta,
981 struct ieee802_11_elems *elems,
982 enum ieee80211_self_protected_actioncode ftype,
983 u16 llid, u16 plid)
984 {
985 enum plink_event event = PLINK_UNDEFINED;
986 u8 ie_len = elems->peering_len;
987 bool matches_local;
988
989 matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
990 mesh_matches_local(sdata, elems));
991
992 /* deny open request from non-matching peer */
993 if (!matches_local && !sta) {
994 event = OPN_RJCT;
995 goto out;
996 }
997
998 if (!sta) {
999 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
1000 mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
1001 goto out;
1002 }
1003 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
1004 if (!mesh_plink_free_count(sdata)) {
1005 mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
1006 goto out;
1007 }
1008
1009 /* new matching peer */
1010 event = OPN_ACPT;
1011 goto out;
1012 } else {
1013 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
1014 mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
1015 goto out;
1016 }
1017 if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
1018 goto out;
1019 }
1020
1021 switch (ftype) {
1022 case WLAN_SP_MESH_PEERING_OPEN:
1023 if (!matches_local)
1024 event = OPN_RJCT;
1025 if (!mesh_plink_free_count(sdata) ||
1026 (sta->mesh->plid && sta->mesh->plid != plid))
1027 event = OPN_IGNR;
1028 else
1029 event = OPN_ACPT;
1030 break;
1031 case WLAN_SP_MESH_PEERING_CONFIRM:
1032 if (!matches_local)
1033 event = CNF_RJCT;
1034 if (!mesh_plink_free_count(sdata) ||
1035 sta->mesh->llid != llid ||
1036 (sta->mesh->plid && sta->mesh->plid != plid))
1037 event = CNF_IGNR;
1038 else
1039 event = CNF_ACPT;
1040 break;
1041 case WLAN_SP_MESH_PEERING_CLOSE:
1042 if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1043 /* Do not check for llid or plid. This does not
1044 * follow the standard but since multiple plinks
1045 * per sta are not supported, it is necessary in
1046 * order to avoid a livelock when MP A sees an
1047 * establish peer link to MP B but MP B does not
1048 * see it. This can be caused by a timeout in
1049 * B's peer link establishment or B beign
1050 * restarted.
1051 */
1052 event = CLS_ACPT;
1053 else if (sta->mesh->plid != plid)
1054 event = CLS_IGNR;
1055 else if (ie_len == 8 && sta->mesh->llid != llid)
1056 event = CLS_IGNR;
1057 else
1058 event = CLS_ACPT;
1059 break;
1060 default:
1061 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1062 break;
1063 }
1064
1065 out:
1066 return event;
1067 }
1068
1069 static void
mesh_process_plink_frame(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,struct ieee802_11_elems * elems)1070 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1071 struct ieee80211_mgmt *mgmt,
1072 struct ieee802_11_elems *elems)
1073 {
1074
1075 struct sta_info *sta;
1076 enum plink_event event;
1077 enum ieee80211_self_protected_actioncode ftype;
1078 u32 changed = 0;
1079 u8 ie_len = elems->peering_len;
1080 u16 plid, llid = 0;
1081
1082 if (!elems->peering) {
1083 mpl_dbg(sdata,
1084 "Mesh plink: missing necessary peer link ie\n");
1085 return;
1086 }
1087
1088 if (elems->rsn_len &&
1089 sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1090 mpl_dbg(sdata,
1091 "Mesh plink: can't establish link with secure peer\n");
1092 return;
1093 }
1094
1095 ftype = mgmt->u.action.u.self_prot.action_code;
1096 if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1097 (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1098 (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1099 && ie_len != 8)) {
1100 mpl_dbg(sdata,
1101 "Mesh plink: incorrect plink ie length %d %d\n",
1102 ftype, ie_len);
1103 return;
1104 }
1105
1106 if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1107 (!elems->mesh_id || !elems->mesh_config)) {
1108 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1109 return;
1110 }
1111 /* Note the lines below are correct, the llid in the frame is the plid
1112 * from the point of view of this host.
1113 */
1114 plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1115 if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1116 (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1117 llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1118
1119 /* WARNING: Only for sta pointer, is dropped & re-acquired */
1120 rcu_read_lock();
1121
1122 sta = sta_info_get(sdata, mgmt->sa);
1123
1124 if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1125 !rssi_threshold_check(sdata, sta)) {
1126 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1127 mgmt->sa);
1128 goto unlock_rcu;
1129 }
1130
1131 /* Now we will figure out the appropriate event... */
1132 event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1133
1134 if (event == OPN_ACPT) {
1135 rcu_read_unlock();
1136 /* allocate sta entry if necessary and update info */
1137 sta = mesh_sta_info_get(sdata, mgmt->sa, elems);
1138 if (!sta) {
1139 mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1140 goto unlock_rcu;
1141 }
1142 sta->mesh->plid = plid;
1143 } else if (!sta && event == OPN_RJCT) {
1144 mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1145 mgmt->sa, 0, plid,
1146 WLAN_REASON_MESH_CONFIG);
1147 goto unlock_rcu;
1148 } else if (!sta || event == PLINK_UNDEFINED) {
1149 /* something went wrong */
1150 goto unlock_rcu;
1151 }
1152
1153 if (event == CNF_ACPT) {
1154 /* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1155 if (!sta->mesh->plid)
1156 sta->mesh->plid = plid;
1157
1158 sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1159 }
1160
1161 changed |= mesh_plink_fsm(sdata, sta, event);
1162
1163 unlock_rcu:
1164 rcu_read_unlock();
1165
1166 if (changed)
1167 ieee80211_mbss_info_change_notify(sdata, changed);
1168 }
1169
mesh_rx_plink_frame(struct ieee80211_sub_if_data * sdata,struct ieee80211_mgmt * mgmt,size_t len,struct ieee80211_rx_status * rx_status)1170 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1171 struct ieee80211_mgmt *mgmt, size_t len,
1172 struct ieee80211_rx_status *rx_status)
1173 {
1174 struct ieee802_11_elems elems;
1175 size_t baselen;
1176 u8 *baseaddr;
1177
1178 /* need action_code, aux */
1179 if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1180 return;
1181
1182 if (sdata->u.mesh.user_mpm)
1183 /* userspace must register for these */
1184 return;
1185
1186 if (is_multicast_ether_addr(mgmt->da)) {
1187 mpl_dbg(sdata,
1188 "Mesh plink: ignore frame from multicast address\n");
1189 return;
1190 }
1191
1192 baseaddr = mgmt->u.action.u.self_prot.variable;
1193 baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1194 if (mgmt->u.action.u.self_prot.action_code ==
1195 WLAN_SP_MESH_PEERING_CONFIRM) {
1196 baseaddr += 4;
1197 baselen += 4;
1198
1199 if (baselen > len)
1200 return;
1201 }
1202 ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems);
1203 mesh_process_plink_frame(sdata, mgmt, &elems);
1204 }
1205
