net/mac80211/mesh_plink.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Copyright (C) 2019 Intel Corporation
   4  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/gfp.h>
  11 #include <linux/kernel.h>
  12 #include <linux/random.h>
  13 #include <linux/rculist.h>
  14
  15 #include "ieee80211_i.h"
  16 #include "rate.h"
  17 #include "mesh.h"
  18
  19 #define PLINK_CNF_AID(mgmt) ((mgmt)->u.action.u.self_prot.variable + 2)
  20 #define PLINK_GET_LLID(p) (p + 2)
  21 #define PLINK_GET_PLID(p) (p + 4)
  22
  23 #define mod_plink_timer(s, t) (mod_timer(&s->mesh->plink_timer, \
  24                                 jiffies + msecs_to_jiffies(t)))
  25
  26 enum plink_event {
  27         PLINK_UNDEFINED,
  28         OPN_ACPT,
  29         OPN_RJCT,
  30         OPN_IGNR,
  31         CNF_ACPT,
  32         CNF_RJCT,
  33         CNF_IGNR,
  34         CLS_ACPT,
  35         CLS_IGNR
  36 };
  37
  38 static const char * const mplstates[] = {
  39         [NL80211_PLINK_LISTEN] = "LISTEN",
  40         [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
  41         [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
  42         [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
  43         [NL80211_PLINK_ESTAB] = "ESTAB",
  44         [NL80211_PLINK_HOLDING] = "HOLDING",
  45         [NL80211_PLINK_BLOCKED] = "BLOCKED"
  46 };
  47
  48 static const char * const mplevents[] = {
  49         [PLINK_UNDEFINED] = "NONE",
  50         [OPN_ACPT] = "OPN_ACPT",
  51         [OPN_RJCT] = "OPN_RJCT",
  52         [OPN_IGNR] = "OPN_IGNR",
  53         [CNF_ACPT] = "CNF_ACPT",
  54         [CNF_RJCT] = "CNF_RJCT",
  55         [CNF_IGNR] = "CNF_IGNR",
  56         [CLS_ACPT] = "CLS_ACPT",
  57         [CLS_IGNR] = "CLS_IGNR"
  58 };
  59
  60 /* We only need a valid sta if user configured a minimum rssi_threshold. */
  61 static bool rssi_threshold_check(struct ieee80211_sub_if_data *sdata,
  62                                  struct sta_info *sta)
  63 {
  64         s32 rssi_threshold = sdata->u.mesh.mshcfg.rssi_threshold;
  65         return rssi_threshold == 0 ||
  66                (sta &&
  67                 (s8)-ewma_signal_read(&sta->rx_stats_avg.signal) >
  68                                                 rssi_threshold);
  69 }
  70
  71 /**
  72  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  73  *
  74  * @sta: mesh peer link to restart
  75  *
  76  * Locking: this function must be called holding sta->mesh->plink_lock
  77  */
  78 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  79 {
  80         lockdep_assert_held(&sta->mesh->plink_lock);
  81         sta->mesh->plink_state = NL80211_PLINK_LISTEN;
  82         sta->mesh->llid = sta->mesh->plid = sta->mesh->reason = 0;
  83         sta->mesh->plink_retries = 0;
  84 }
  85
  86 /*
  87  * mesh_set_short_slot_time - enable / disable ERP short slot time.
  88  *
  89  * The standard indirectly mandates mesh STAs to turn off short slot time by
  90  * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
  91  * can't be sneaky about it. Enable short slot time if all mesh STAs in the
  92  * MBSS support ERP rates.
  93  *
  94  * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
  95  */
  96 static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
  97 {
  98         struct ieee80211_local *local = sdata->local;
  99         struct ieee80211_supported_band *sband;
 100         struct sta_info *sta;
 101         u32 erp_rates = 0, changed = 0;
 102         int i;
 103         bool short_slot = false;
 104
 105         sband = ieee80211_get_sband(sdata);
 106         if (!sband)
 107                 return changed;
 108
 109         if (sband->band == NL80211_BAND_5GHZ) {
 110                 /* (IEEE 802.11-2012 19.4.5) */
 111                 short_slot = true;
 112                 goto out;
 113         } else if (sband->band != NL80211_BAND_2GHZ) {
 114                 goto out;
 115         }
 116
 117         for (i = 0; i < sband->n_bitrates; i++)
 118                 if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
 119                         erp_rates |= BIT(i);
 120
 121         if (!erp_rates)
 122                 goto out;
 123
 124         rcu_read_lock();
 125         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 126                 if (sdata != sta->sdata ||
 127                     sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 128                         continue;
 129
 130                 short_slot = false;
 131                 if (erp_rates & sta->sta.supp_rates[sband->band])
 132                         short_slot = true;
 133                  else
 134                         break;
 135         }
 136         rcu_read_unlock();
 137
 138 out:
 139         if (sdata->vif.bss_conf.use_short_slot != short_slot) {
 140                 sdata->vif.bss_conf.use_short_slot = short_slot;
 141                 changed = BSS_CHANGED_ERP_SLOT;
 142                 mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
 143                         sdata->vif.addr, short_slot);
 144         }
 145         return changed;
 146 }
 147
 148 /**
 149  * mesh_set_ht_prot_mode - set correct HT protection mode
 150  *
 151  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 152  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 153  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 154  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 155  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 156  * HT20 peer is present. Otherwise no-protection mode is selected.
 157  */
 158 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 159 {
 160         struct ieee80211_local *local = sdata->local;
 161         struct sta_info *sta;
 162         u16 ht_opmode;
 163         bool non_ht_sta = false, ht20_sta = false;
 164
 165         switch (sdata->vif.bss_conf.chandef.width) {
 166         case NL80211_CHAN_WIDTH_20_NOHT:
 167         case NL80211_CHAN_WIDTH_5:
 168         case NL80211_CHAN_WIDTH_10:
 169                 return 0;
 170         default:
 171                 break;
 172         }
 173
 174         rcu_read_lock();
 175         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 176                 if (sdata != sta->sdata ||
 177                     sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 178                         continue;
 179
 180                 if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
 181                         continue;
 182
 183                 if (!sta->sta.ht_cap.ht_supported) {
 184                         mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
 185                                        sta->sta.addr);
 186                         non_ht_sta = true;
 187                         break;
 188                 }
 189
 190                 mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
 191                 ht20_sta = true;
 192         }
 193         rcu_read_unlock();
 194
 195         if (non_ht_sta)
 196                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 197         else if (ht20_sta &&
 198                  sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
 199                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 200         else
 201                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 202
 203         if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
 204                 return 0;
 205
 206         sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 207         sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 208         mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
 209         return BSS_CHANGED_HT;
 210 }
 211
 212 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 213                                struct sta_info *sta,
 214                                enum ieee80211_self_protected_actioncode action,
 215                                u8 *da, u16 llid, u16 plid, u16 reason)
 216 {
 217         struct ieee80211_local *local = sdata->local;
 218         struct sk_buff *skb;
 219         struct ieee80211_tx_info *info;
 220         struct ieee80211_mgmt *mgmt;
 221         bool include_plid = false;
 222         u16 peering_proto = 0;
 223         u8 *pos, ie_len = 4;
 224         int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.self_prot);
 225         int err = -ENOMEM;
 226
 227         skb = dev_alloc_skb(local->tx_headroom +
 228                             hdr_len +
 229                             2 + /* capability info */
 230                             2 + /* AID */
 231                             2 + 8 + /* supported rates */
 232                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 233                             2 + sdata->u.mesh.mesh_id_len +
 234                             2 + sizeof(struct ieee80211_meshconf_ie) +
 235                             2 + sizeof(struct ieee80211_ht_cap) +
 236                             2 + sizeof(struct ieee80211_ht_operation) +
 237                             2 + sizeof(struct ieee80211_vht_cap) +
 238                             2 + sizeof(struct ieee80211_vht_operation) +
 239                             2 + 8 + /* peering IE */
 240                             sdata->u.mesh.ie_len);
 241         if (!skb)
 242                 return err;
 243         info = IEEE80211_SKB_CB(skb);
 244         skb_reserve(skb, local->tx_headroom);
 245         mgmt = skb_put_zero(skb, hdr_len);
 246         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 247                                           IEEE80211_STYPE_ACTION);
 248         memcpy(mgmt->da, da, ETH_ALEN);
 249         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 250         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 251         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 252         mgmt->u.action.u.self_prot.action_code = action;
 253
 254         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 255                 struct ieee80211_supported_band *sband;
 256                 enum nl80211_band band;
 257
 258                 sband = ieee80211_get_sband(sdata);
 259                 if (!sband) {
 260                         err = -EINVAL;
 261                         goto free;
 262                 }
 263                 band = sband->band;
 264
 265                 /* capability info */
 266                 pos = skb_put_zero(skb, 2);
 267                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 268                         /* AID */
 269                         pos = skb_put(skb, 2);
 270                         put_unaligned_le16(sta->sta.aid, pos);
 271                 }
 272                 if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
 273                     ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
 274                     mesh_add_rsn_ie(sdata, skb) ||
 275                     mesh_add_meshid_ie(sdata, skb) ||
 276                     mesh_add_meshconf_ie(sdata, skb))
 277                         goto free;
 278         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 279                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
 280                 if (mesh_add_meshid_ie(sdata, skb))
 281                         goto free;
 282         }
 283
 284         /* Add Mesh Peering Management element */
 285         switch (action) {
 286         case WLAN_SP_MESH_PEERING_OPEN:
 287                 break;
 288         case WLAN_SP_MESH_PEERING_CONFIRM:
 289                 ie_len += 2;
 290                 include_plid = true;
 291                 break;
 292         case WLAN_SP_MESH_PEERING_CLOSE:
 293                 if (plid) {
 294                         ie_len += 2;
 295                         include_plid = true;
 296                 }
 297                 ie_len += 2;    /* reason code */
 298                 break;
 299         default:
 300                 err = -EINVAL;
 301                 goto free;
 302         }
 303
 304         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 305                 goto free;
 306
 307         pos = skb_put(skb, 2 + ie_len);
 308         *pos++ = WLAN_EID_PEER_MGMT;
 309         *pos++ = ie_len;
 310         memcpy(pos, &peering_proto, 2);
 311         pos += 2;
 312         put_unaligned_le16(llid, pos);
 313         pos += 2;
 314         if (include_plid) {
 315                 put_unaligned_le16(plid, pos);
 316                 pos += 2;
 317         }
 318         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 319                 put_unaligned_le16(reason, pos);
 320                 pos += 2;
 321         }
 322
 323         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 324                 if (mesh_add_ht_cap_ie(sdata, skb) ||
 325                     mesh_add_ht_oper_ie(sdata, skb) ||
 326                     mesh_add_vht_cap_ie(sdata, skb) ||
 327                     mesh_add_vht_oper_ie(sdata, skb))
 328                         goto free;
 329         }
 330
 331         if (mesh_add_vendor_ies(sdata, skb))
 332                 goto free;
 333
 334         ieee80211_tx_skb(sdata, skb);
 335         return 0;
 336 free:
 337         kfree_skb(skb);
 338         return err;
 339 }
 340
 341 /**
 342  * __mesh_plink_deactivate - deactivate mesh peer link
 343  *
 344  * @sta: mesh peer link to deactivate
 345  *
 346  * Mesh paths with this peer as next hop should be flushed
 347  * by the caller outside of plink_lock.
 348  *
 349  * Returns beacon changed flag if the beacon content changed.
 350  *
 351  * Locking: the caller must hold sta->mesh->plink_lock
 352  */
 353 static u32 __mesh_plink_deactivate(struct sta_info *sta)
 354 {
 355         struct ieee80211_sub_if_data *sdata = sta->sdata;
 356         u32 changed = 0;
 357
 358         lockdep_assert_held(&sta->mesh->plink_lock);
 359
 360         if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
 361                 changed = mesh_plink_dec_estab_count(sdata);
 362         sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 363
 364         ieee80211_mps_sta_status_update(sta);
 365         changed |= ieee80211_mps_set_sta_local_pm(sta,
 366                         NL80211_MESH_POWER_UNKNOWN);
 367
 368         return changed;
 369 }
 370
 371 /**
 372  * mesh_plink_deactivate - deactivate mesh peer link
 373  *
 374  * @sta: mesh peer link to deactivate
 375  *
 376  * All mesh paths with this peer as next hop will be flushed
 377  */
 378 u32 mesh_plink_deactivate(struct sta_info *sta)
 379 {
 380         struct ieee80211_sub_if_data *sdata = sta->sdata;
 381         u32 changed;
 382
 383         spin_lock_bh(&sta->mesh->plink_lock);
 384         changed = __mesh_plink_deactivate(sta);
 385
 386         if (!sdata->u.mesh.user_mpm) {
 387                 sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
 388                 mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
 389                                     sta->sta.addr, sta->mesh->llid,
 390                                     sta->mesh->plid, sta->mesh->reason);
 391         }
 392         spin_unlock_bh(&sta->mesh->plink_lock);
 393         if (!sdata->u.mesh.user_mpm)
 394                 del_timer_sync(&sta->mesh->plink_timer);
 395         mesh_path_flush_by_nexthop(sta);
 396
 397         /* make sure no readers can access nexthop sta from here on */
 398         synchronize_net();
 399
 400         return changed;
 401 }
 402
 403 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
 404                                struct sta_info *sta,
 405                                struct ieee802_11_elems *elems)
 406 {
 407         struct ieee80211_local *local = sdata->local;
 408         struct ieee80211_supported_band *sband;
 409         u32 rates, basic_rates = 0, changed = 0;
 410         enum ieee80211_sta_rx_bandwidth bw = sta->sta.bandwidth;
 411
 412         sband = ieee80211_get_sband(sdata);
 413         if (!sband)
 414                 return;
 415
 416         rates = ieee80211_sta_get_rates(sdata, elems, sband->band,
 417                                         &basic_rates);
 418
 419         spin_lock_bh(&sta->mesh->plink_lock);
 420         sta->rx_stats.last_rx = jiffies;
 421
 422         /* rates and capabilities don't change during peering */
 423         if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
 424             sta->mesh->processed_beacon)
 425                 goto out;
 426         sta->mesh->processed_beacon = true;
 427
 428         if (sta->sta.supp_rates[sband->band] != rates)
 429                 changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
 430         sta->sta.supp_rates[sband->band] = rates;
 431
 432         if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 433                                               elems->ht_cap_elem, sta))
 434                 changed |= IEEE80211_RC_BW_CHANGED;
 435
 436         ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
 437                                             elems->vht_cap_elem, sta);
 438
 439         if (bw != sta->sta.bandwidth)
 440                 changed |= IEEE80211_RC_BW_CHANGED;
 441
 442         /* HT peer is operating 20MHz-only */
 443         if (elems->ht_operation &&
 444             !(elems->ht_operation->ht_param &
 445               IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
 446                 if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
 447                         changed |= IEEE80211_RC_BW_CHANGED;
 448                 sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
 449         }
 450
 451         if (!test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
 452                 rate_control_rate_init(sta);
 453         else
 454                 rate_control_rate_update(local, sband, sta, changed);
 455 out:
 456         spin_unlock_bh(&sta->mesh->plink_lock);
 457 }
 458
 459 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
 460 {
 461         struct sta_info *sta;
 462         unsigned long *aid_map;
 463         int aid;
 464
 465         aid_map = kcalloc(BITS_TO_LONGS(IEEE80211_MAX_AID + 1),
 466                           sizeof(*aid_map), GFP_KERNEL);
 467         if (!aid_map)
 468                 return -ENOMEM;
 469
 470         /* reserve aid 0 for mcast indication */
 471         __set_bit(0, aid_map);
 472
 473         rcu_read_lock();
 474         list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
 475                 __set_bit(sta->sta.aid, aid_map);
 476         rcu_read_unlock();
 477
 478         aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
 479         kfree(aid_map);
 480
 481         if (aid > IEEE80211_MAX_AID)
 482                 return -ENOBUFS;
 483
 484         return aid;
 485 }
 486
 487 static struct sta_info *
 488 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
 489 {
 490         struct sta_info *sta;
 491         int aid;
 492
 493         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
 494                 return NULL;
 495
 496         aid = mesh_allocate_aid(sdata);
 497         if (aid < 0)
 498                 return NULL;
 499
 500         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 501         if (!sta)
 502                 return NULL;
 503
 504         sta->mesh->plink_state = NL80211_PLINK_LISTEN;
 505         sta->sta.wme = true;
 506         sta->sta.aid = aid;
 507
 508         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 509         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 510         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 511
 512         return sta;
 513 }
 514
 515 static struct sta_info *
 516 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
 517                     struct ieee802_11_elems *elems,
 518                     struct ieee80211_rx_status *rx_status)
 519 {
 520         struct sta_info *sta = NULL;
 521
 522         /* Userspace handles station allocation */
 523         if (sdata->u.mesh.user_mpm ||
 524             sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
 525                 if (mesh_peer_accepts_plinks(elems) &&
 526                     mesh_plink_availables(sdata)) {
 527                         int sig = 0;
 528
 529                         if (ieee80211_hw_check(&sdata->local->hw, SIGNAL_DBM))
 530                                 sig = rx_status->signal;
 531
 532                         cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 533                                                            elems->ie_start,
 534                                                            elems->total_len,
 535                                                            sig, GFP_KERNEL);
 536                 }
 537         } else
 538                 sta = __mesh_sta_info_alloc(sdata, addr);
 539
 540         return sta;
 541 }
 542
 543 /*
 544  * mesh_sta_info_get - return mesh sta info entry for @addr.
 545  *
 546  * @sdata: local meshif
 547  * @addr: peer's address
 548  * @elems: IEs from beacon or mesh peering frame.
 549  * @rx_status: rx status for the frame for signal reporting
 550  *
 551  * Return existing or newly allocated sta_info under RCU read lock.
 552  * (re)initialize with given IEs.
 553  */
 554 static struct sta_info *
 555 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
 556                   u8 *addr, struct ieee802_11_elems *elems,
 557                   struct ieee80211_rx_status *rx_status) __acquires(RCU)
 558 {
 559         struct sta_info *sta = NULL;
 560
 561         rcu_read_lock();
 562         sta = sta_info_get(sdata, addr);
 563         if (sta) {
 564                 mesh_sta_info_init(sdata, sta, elems);
 565         } else {
 566                 rcu_read_unlock();
 567                 /* can't run atomic */
 568                 sta = mesh_sta_info_alloc(sdata, addr, elems, rx_status);
 569                 if (!sta) {
 570                         rcu_read_lock();
 571                         return NULL;
 572                 }
 573
 574                 mesh_sta_info_init(sdata, sta, elems);
 575
 576                 if (sta_info_insert_rcu(sta))
 577                         return NULL;
 578         }
 579
 580         return sta;
 581 }
 582
 583 /*
 584  * mesh_neighbour_update - update or initialize new mesh neighbor.
 585  *
 586  * @sdata: local meshif
 587  * @addr: peer's address
 588  * @elems: IEs from beacon or mesh peering frame
 589  * @rx_status: rx status for the frame for signal reporting
 590  *
 591  * Initiates peering if appropriate.
 592  */
 593 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 594                            u8 *hw_addr,
 595                            struct ieee802_11_elems *elems,
 596                            struct ieee80211_rx_status *rx_status)
 597 {
 598         struct sta_info *sta;
 599         u32 changed = 0;
 600
 601         sta = mesh_sta_info_get(sdata, hw_addr, elems, rx_status);
 602         if (!sta)
 603                 goto out;
 604
 605         sta->mesh->connected_to_gate = elems->mesh_config->meshconf_form &
 606                 IEEE80211_MESHCONF_FORM_CONNECTED_TO_GATE;
 607
 608         if (mesh_peer_accepts_plinks(elems) &&
 609             sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
 610             sdata->u.mesh.accepting_plinks &&
 611             sdata->u.mesh.mshcfg.auto_open_plinks &&
 612             rssi_threshold_check(sdata, sta))
 613                 changed = mesh_plink_open(sta);
 614
 615         ieee80211_mps_frame_release(sta, elems);
 616 out:
 617         rcu_read_unlock();
 618         ieee80211_mbss_info_change_notify(sdata, changed);
 619 }
 620
 621 void mesh_plink_timer(struct timer_list *t)
 622 {
 623         struct mesh_sta *mesh = from_timer(mesh, t, plink_timer);
 624         struct sta_info *sta;
 625         u16 reason = 0;
 626         struct ieee80211_sub_if_data *sdata;
 627         struct mesh_config *mshcfg;
 628         enum ieee80211_self_protected_actioncode action = 0;
 629
 630         /*
 631          * This STA is valid because sta_info_destroy() will
 632          * del_timer_sync() this timer after having made sure
 633          * it cannot be readded (by deleting the plink.)
 634          */
 635         sta = mesh->plink_sta;
 636
 637         if (sta->sdata->local->quiescing)
 638                 return;
 639
 640         spin_lock_bh(&sta->mesh->plink_lock);
 641
 642         /* If a timer fires just before a state transition on another CPU,
 643          * we may have already extended the timeout and changed state by the
 644          * time we've acquired the lock and arrived  here.  In that case,
 645          * skip this timer and wait for the new one.
 646          */
 647         if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
 648                 mpl_dbg(sta->sdata,
 649                         "Ignoring timer for %pM in state %s (timer adjusted)",
 650                         sta->sta.addr, mplstates[sta->mesh->plink_state]);
 651                 spin_unlock_bh(&sta->mesh->plink_lock);
 652                 return;
 653         }
 654
 655         /* del_timer() and handler may race when entering these states */
 656         if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
 657             sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
 658                 mpl_dbg(sta->sdata,
 659                         "Ignoring timer for %pM in state %s (timer deleted)",
 660                         sta->sta.addr, mplstates[sta->mesh->plink_state]);
 661                 spin_unlock_bh(&sta->mesh->plink_lock);
 662                 return;
 663         }
 664
 665         mpl_dbg(sta->sdata,
 666                 "Mesh plink timer for %pM fired on state %s\n",
 667                 sta->sta.addr, mplstates[sta->mesh->plink_state]);
 668         sdata = sta->sdata;
 669         mshcfg = &sdata->u.mesh.mshcfg;
 670
 671         switch (sta->mesh->plink_state) {
 672         case NL80211_PLINK_OPN_RCVD:
 673         case NL80211_PLINK_OPN_SNT:
 674                 /* retry timer */
 675                 if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
 676                         u32 rand;
 677                         mpl_dbg(sta->sdata,
 678                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 679                                 sta->sta.addr, sta->mesh->plink_retries,
 680                                 sta->mesh->plink_timeout);
 681                         get_random_bytes(&rand, sizeof(u32));
 682                         sta->mesh->plink_timeout = sta->mesh->plink_timeout +
 683                                              rand % sta->mesh->plink_timeout;
 684                         ++sta->mesh->plink_retries;
 685                         mod_plink_timer(sta, sta->mesh->plink_timeout);
 686                         action = WLAN_SP_MESH_PEERING_OPEN;
 687                         break;
 688                 }
 689                 reason = WLAN_REASON_MESH_MAX_RETRIES;
 690                 /* fall through */
 691         case NL80211_PLINK_CNF_RCVD:
 692                 /* confirm timer */
 693                 if (!reason)
 694                         reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
 695                 sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 696                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 697                 action = WLAN_SP_MESH_PEERING_CLOSE;
 698                 break;
 699         case NL80211_PLINK_HOLDING:
 700                 /* holding timer */
 701                 del_timer(&sta->mesh->plink_timer);
 702                 mesh_plink_fsm_restart(sta);
 703                 break;
 704         default:
 705                 break;
 706         }
 707         spin_unlock_bh(&sta->mesh->plink_lock);
 708         if (action)
 709                 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 710                                     sta->mesh->llid, sta->mesh->plid, reason);
 711 }
 712
 713 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
 714 {
 715         sta->mesh->plink_timeout = timeout;
 716         mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
 717 }
 718
 719 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
 720                         u16 llid)
 721 {
 722         struct ieee80211_local *local = sdata->local;
 723         bool in_use = false;
 724         struct sta_info *sta;
 725
 726         rcu_read_lock();
 727         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 728                 if (sdata != sta->sdata)
 729                         continue;
 730
 731                 if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
 732                         in_use = true;
 733                         break;
 734                 }
 735         }
 736         rcu_read_unlock();
 737
 738         return in_use;
 739 }
 740
 741 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 742 {
 743         u16 llid;
 744
 745         do {
 746                 get_random_bytes(&llid, sizeof(llid));
 747         } while (llid_in_use(sdata, llid));
 748
 749         return llid;
 750 }
 751
 752 u32 mesh_plink_open(struct sta_info *sta)
 753 {
 754         struct ieee80211_sub_if_data *sdata = sta->sdata;
 755         u32 changed;
 756
 757         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 758                 return 0;
 759
 760         spin_lock_bh(&sta->mesh->plink_lock);
 761         sta->mesh->llid = mesh_get_new_llid(sdata);
 762         if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
 763             sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
 764                 spin_unlock_bh(&sta->mesh->plink_lock);
 765                 return 0;
 766         }
 767         sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
 768         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 769         spin_unlock_bh(&sta->mesh->plink_lock);
 770         mpl_dbg(sdata,
 771                 "Mesh plink: starting establishment with %pM\n",
 772                 sta->sta.addr);
 773
 774         /* set the non-peer mode to active during peering */
 775         changed = ieee80211_mps_local_status_update(sdata);
 776
 777         mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
 778                             sta->sta.addr, sta->mesh->llid, 0, 0);
 779         return changed;
 780 }
 781
 782 u32 mesh_plink_block(struct sta_info *sta)
 783 {
 784         u32 changed;
 785
 786         spin_lock_bh(&sta->mesh->plink_lock);
 787         changed = __mesh_plink_deactivate(sta);
 788         sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 789         spin_unlock_bh(&sta->mesh->plink_lock);
 790         mesh_path_flush_by_nexthop(sta);
 791
 792         return changed;
 793 }
 794
 795 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
 796                              struct sta_info *sta,
 797                              enum plink_event event)
 798 {
 799         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 800         u16 reason = (event == CLS_ACPT) ?
 801                      WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
 802
 803         sta->mesh->reason = reason;
 804         sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 805         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 806 }
 807
 808 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
 809                                 struct sta_info *sta)
 810 {
 811         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 812         u32 changed = 0;
 813
 814         del_timer(&sta->mesh->plink_timer);
 815         sta->mesh->plink_state = NL80211_PLINK_ESTAB;
 816         changed |= mesh_plink_inc_estab_count(sdata);
 817         changed |= mesh_set_ht_prot_mode(sdata);
 818         changed |= mesh_set_short_slot_time(sdata);
 819         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
 820         ieee80211_mps_sta_status_update(sta);
 821         changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
 822         return changed;
 823 }
 824
 825 /**
 826  * mesh_plink_fsm - step @sta MPM based on @event
 827  *
 828  * @sdata: interface
 829  * @sta: mesh neighbor
 830  * @event: peering event
 831  *
 832  * Return: changed MBSS flags
 833  */
 834 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
 835                           struct sta_info *sta, enum plink_event event)
 836 {
 837         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 838         enum ieee80211_self_protected_actioncode action = 0;
 839         u32 changed = 0;
 840         bool flush = false;
 841
 842         mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
 843                 mplstates[sta->mesh->plink_state], mplevents[event]);
 844
 845         spin_lock_bh(&sta->mesh->plink_lock);
 846         switch (sta->mesh->plink_state) {
 847         case NL80211_PLINK_LISTEN:
 848                 switch (event) {
 849                 case CLS_ACPT:
 850                         mesh_plink_fsm_restart(sta);
 851                         break;
 852                 case OPN_ACPT:
 853                         sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 854                         sta->mesh->llid = mesh_get_new_llid(sdata);
 855                         mesh_plink_timer_set(sta,
 856                                              mshcfg->dot11MeshRetryTimeout);
 857
 858                         /* set the non-peer mode to active during peering */
 859                         changed |= ieee80211_mps_local_status_update(sdata);
 860                         action = WLAN_SP_MESH_PEERING_OPEN;
 861                         break;
 862                 default:
 863                         break;
 864                 }
 865                 break;
 866         case NL80211_PLINK_OPN_SNT:
 867                 switch (event) {
 868                 case OPN_RJCT:
 869                 case CNF_RJCT:
 870                 case CLS_ACPT:
 871                         mesh_plink_close(sdata, sta, event);
 872                         action = WLAN_SP_MESH_PEERING_CLOSE;
 873                         break;
 874                 case OPN_ACPT:
 875                         /* retry timer is left untouched */
 876                         sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 877                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 878                         break;
 879                 case CNF_ACPT:
 880                         sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
 881                         mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
 882                         break;
 883                 default:
 884                         break;
 885                 }
 886                 break;
 887         case NL80211_PLINK_OPN_RCVD:
 888                 switch (event) {
 889                 case OPN_RJCT:
 890                 case CNF_RJCT:
 891                 case CLS_ACPT:
 892                         mesh_plink_close(sdata, sta, event);
 893                         action = WLAN_SP_MESH_PEERING_CLOSE;
 894                         break;
 895                 case OPN_ACPT:
 896                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 897                         break;
 898                 case CNF_ACPT:
 899                         changed |= mesh_plink_establish(sdata, sta);
 900                         break;
 901                 default:
 902                         break;
 903                 }
 904                 break;
 905         case NL80211_PLINK_CNF_RCVD:
 906                 switch (event) {
 907                 case OPN_RJCT:
 908                 case CNF_RJCT:
 909                 case CLS_ACPT:
 910                         mesh_plink_close(sdata, sta, event);
 911                         action = WLAN_SP_MESH_PEERING_CLOSE;
 912                         break;
 913                 case OPN_ACPT:
 914                         changed |= mesh_plink_establish(sdata, sta);
 915                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 916                         break;
 917                 default:
 918                         break;
 919                 }
 920                 break;
 921         case NL80211_PLINK_ESTAB:
 922                 switch (event) {
 923                 case CLS_ACPT:
 924                         changed |= __mesh_plink_deactivate(sta);
 925                         changed |= mesh_set_ht_prot_mode(sdata);
 926                         changed |= mesh_set_short_slot_time(sdata);
 927                         mesh_plink_close(sdata, sta, event);
 928                         action = WLAN_SP_MESH_PEERING_CLOSE;
 929                         flush = true;
 930                         break;
 931                 case OPN_ACPT:
 932                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 933                         break;
 934                 default:
 935                         break;
 936                 }
 937                 break;
 938         case NL80211_PLINK_HOLDING:
 939                 switch (event) {
 940                 case CLS_ACPT:
 941                         del_timer(&sta->mesh->plink_timer);
 942                         mesh_plink_fsm_restart(sta);
 943                         break;
 944                 case OPN_ACPT:
 945                 case CNF_ACPT:
 946                 case OPN_RJCT:
 947                 case CNF_RJCT:
 948                         action = WLAN_SP_MESH_PEERING_CLOSE;
 949                         break;
 950                 default:
 951                         break;
 952                 }
 953                 break;
 954         default:
 955                 /* should not get here, PLINK_BLOCKED is dealt with at the
 956                  * beginning of the function
 957                  */
 958                 break;
 959         }
 960         spin_unlock_bh(&sta->mesh->plink_lock);
 961         if (flush)
 962                 mesh_path_flush_by_nexthop(sta);
 963         if (action) {
 964                 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 965                                     sta->mesh->llid, sta->mesh->plid,
 966                                     sta->mesh->reason);
 967
 968                 /* also send confirm in open case */
 969                 if (action == WLAN_SP_MESH_PEERING_OPEN) {
 970                         mesh_plink_frame_tx(sdata, sta,
 971                                             WLAN_SP_MESH_PEERING_CONFIRM,
 972                                             sta->sta.addr, sta->mesh->llid,
 973                                             sta->mesh->plid, 0);
 974                 }
 975         }
 976
 977         return changed;
 978 }
 979
 980 /*
 981  * mesh_plink_get_event - get correct MPM event
 982  *
 983  * @sdata: interface
 984  * @sta: peer, leave NULL if processing a frame from a new suitable peer
 985  * @elems: peering management IEs
 986  * @ftype: frame type
 987  * @llid: peer's peer link ID
 988  * @plid: peer's local link ID
 989  *
 990  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
 991  * an error.
 992  */
 993 static enum plink_event
 994 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
 995                      struct sta_info *sta,
 996                      struct ieee802_11_elems *elems,
 997                      enum ieee80211_self_protected_actioncode ftype,
 998                      u16 llid, u16 plid)
 999 {
1000         enum plink_event event = PLINK_UNDEFINED;
1001         u8 ie_len = elems->peering_len;
1002         bool matches_local;
1003
1004         matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
1005                          mesh_matches_local(sdata, elems));
1006
1007         /* deny open request from non-matching peer */
1008         if (!matches_local && !sta) {
1009                 event = OPN_RJCT;
1010                 goto out;
1011         }
1012
1013         if (!sta) {
1014                 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
1015                         mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
1016                         goto out;
1017                 }
1018                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
1019                 if (!mesh_plink_free_count(sdata)) {
1020                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
1021                         goto out;
1022                 }
1023
1024                 /* new matching peer */
1025                 event = OPN_ACPT;
1026                 goto out;
1027         } else {
1028                 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
1029                         mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
1030                         goto out;
1031                 }
1032                 if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
1033                         goto out;
1034         }
1035
1036         switch (ftype) {
1037         case WLAN_SP_MESH_PEERING_OPEN:
1038                 if (!matches_local)
1039                         event = OPN_RJCT;
1040                 if (!mesh_plink_free_count(sdata) ||
1041                     (sta->mesh->plid && sta->mesh->plid != plid))
1042                         event = OPN_IGNR;
1043                 else
1044                         event = OPN_ACPT;
1045                 break;
1046         case WLAN_SP_MESH_PEERING_CONFIRM:
1047                 if (!matches_local)
1048                         event = CNF_RJCT;
1049                 if (!mesh_plink_free_count(sdata) ||
1050                     sta->mesh->llid != llid ||
1051                     (sta->mesh->plid && sta->mesh->plid != plid))
1052                         event = CNF_IGNR;
1053                 else
1054                         event = CNF_ACPT;
1055                 break;
1056         case WLAN_SP_MESH_PEERING_CLOSE:
1057                 if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1058                         /* Do not check for llid or plid. This does not
1059                          * follow the standard but since multiple plinks
1060                          * per sta are not supported, it is necessary in
1061                          * order to avoid a livelock when MP A sees an
1062                          * establish peer link to MP B but MP B does not
1063                          * see it. This can be caused by a timeout in
1064                          * B's peer link establishment or B beign
1065                          * restarted.
1066                          */
1067                         event = CLS_ACPT;
1068                 else if (sta->mesh->plid != plid)
1069                         event = CLS_IGNR;
1070                 else if (ie_len == 8 && sta->mesh->llid != llid)
1071                         event = CLS_IGNR;
1072                 else
1073                         event = CLS_ACPT;
1074                 break;
1075         default:
1076                 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1077                 break;
1078         }
1079
1080 out:
1081         return event;
1082 }
1083
1084 static void
1085 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1086                          struct ieee80211_mgmt *mgmt,
1087                          struct ieee802_11_elems *elems,
1088                          struct ieee80211_rx_status *rx_status)
1089 {
1090
1091         struct sta_info *sta;
1092         enum plink_event event;
1093         enum ieee80211_self_protected_actioncode ftype;
1094         u32 changed = 0;
1095         u8 ie_len = elems->peering_len;
1096         u16 plid, llid = 0;
1097
1098         if (!elems->peering) {
1099                 mpl_dbg(sdata,
1100                         "Mesh plink: missing necessary peer link ie\n");
1101                 return;
1102         }
1103
1104         if (elems->rsn_len &&
1105             sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1106                 mpl_dbg(sdata,
1107                         "Mesh plink: can't establish link with secure peer\n");
1108                 return;
1109         }
1110
1111         ftype = mgmt->u.action.u.self_prot.action_code;
1112         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1113             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1114             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1115                                                         && ie_len != 8)) {
1116                 mpl_dbg(sdata,
1117                         "Mesh plink: incorrect plink ie length %d %d\n",
1118                         ftype, ie_len);
1119                 return;
1120         }
1121
1122         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1123             (!elems->mesh_id || !elems->mesh_config)) {
1124                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1125                 return;
1126         }
1127         /* Note the lines below are correct, the llid in the frame is the plid
1128          * from the point of view of this host.
1129          */
1130         plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1131         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1132             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1133                 llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1134
1135         /* WARNING: Only for sta pointer, is dropped & re-acquired */
1136         rcu_read_lock();
1137
1138         sta = sta_info_get(sdata, mgmt->sa);
1139
1140         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1141             !rssi_threshold_check(sdata, sta)) {
1142                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1143                         mgmt->sa);
1144                 goto unlock_rcu;
1145         }
1146
1147         /* Now we will figure out the appropriate event... */
1148         event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1149
1150         if (event == OPN_ACPT) {
1151                 rcu_read_unlock();
1152                 /* allocate sta entry if necessary and update info */
1153                 sta = mesh_sta_info_get(sdata, mgmt->sa, elems, rx_status);
1154                 if (!sta) {
1155                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1156                         goto unlock_rcu;
1157                 }
1158                 sta->mesh->plid = plid;
1159         } else if (!sta && event == OPN_RJCT) {
1160                 mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1161                                     mgmt->sa, 0, plid,
1162                                     WLAN_REASON_MESH_CONFIG);
1163                 goto unlock_rcu;
1164         } else if (!sta || event == PLINK_UNDEFINED) {
1165                 /* something went wrong */
1166                 goto unlock_rcu;
1167         }
1168
1169         if (event == CNF_ACPT) {
1170                 /* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1171                 if (!sta->mesh->plid)
1172                         sta->mesh->plid = plid;
1173
1174                 sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1175         }
1176
1177         changed |= mesh_plink_fsm(sdata, sta, event);
1178
1179 unlock_rcu:
1180         rcu_read_unlock();
1181
1182         if (changed)
1183                 ieee80211_mbss_info_change_notify(sdata, changed);
1184 }
1185
1186 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1187                          struct ieee80211_mgmt *mgmt, size_t len,
1188                          struct ieee80211_rx_status *rx_status)
1189 {
1190         struct ieee802_11_elems elems;
1191         size_t baselen;
1192         u8 *baseaddr;
1193
1194         /* need action_code, aux */
1195         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1196                 return;
1197
1198         if (sdata->u.mesh.user_mpm)
1199                 /* userspace must register for these */
1200                 return;
1201
1202         if (is_multicast_ether_addr(mgmt->da)) {
1203                 mpl_dbg(sdata,
1204                         "Mesh plink: ignore frame from multicast address\n");
1205                 return;
1206         }
1207
1208         baseaddr = mgmt->u.action.u.self_prot.variable;
1209         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1210         if (mgmt->u.action.u.self_prot.action_code ==
1211                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
1212                 baseaddr += 4;
1213                 baselen += 4;
1214
1215                 if (baselen > len)
1216                         return;
1217         }
1218         ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems,
1219                                mgmt->bssid, NULL);
1220         mesh_process_plink_frame(sdata, mgmt, &elems, rx_status);
1221 }