net/mac80211/mesh_plink.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2008, 2009 open80211s Ltd.
   4  * Copyright (C) 2019 Intel Corporation
   5  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   6  */
   7 #include <linux/gfp.h>
   8 #include <linux/kernel.h>
   9 #include <linux/random.h>
  10 #include <linux/rculist.h>
  11
  12 #include "ieee80211_i.h"
  13 #include "rate.h"
  14 #include "mesh.h"
  15
  16 #define PLINK_CNF_AID(mgmt) ((mgmt)->u.action.u.self_prot.variable + 2)
  17 #define PLINK_GET_LLID(p) (p + 2)
  18 #define PLINK_GET_PLID(p) (p + 4)
  19
  20 #define mod_plink_timer(s, t) (mod_timer(&s->mesh->plink_timer, \
  21                                 jiffies + msecs_to_jiffies(t)))
  22
  23 enum plink_event {
  24         PLINK_UNDEFINED,
  25         OPN_ACPT,
  26         OPN_RJCT,
  27         OPN_IGNR,
  28         CNF_ACPT,
  29         CNF_RJCT,
  30         CNF_IGNR,
  31         CLS_ACPT,
  32         CLS_IGNR
  33 };
  34
  35 static const char * const mplstates[] = {
  36         [NL80211_PLINK_LISTEN] = "LISTEN",
  37         [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
  38         [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
  39         [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
  40         [NL80211_PLINK_ESTAB] = "ESTAB",
  41         [NL80211_PLINK_HOLDING] = "HOLDING",
  42         [NL80211_PLINK_BLOCKED] = "BLOCKED"
  43 };
  44
  45 static const char * const mplevents[] = {
  46         [PLINK_UNDEFINED] = "NONE",
  47         [OPN_ACPT] = "OPN_ACPT",
  48         [OPN_RJCT] = "OPN_RJCT",
  49         [OPN_IGNR] = "OPN_IGNR",
  50         [CNF_ACPT] = "CNF_ACPT",
  51         [CNF_RJCT] = "CNF_RJCT",
  52         [CNF_IGNR] = "CNF_IGNR",
  53         [CLS_ACPT] = "CLS_ACPT",
  54         [CLS_IGNR] = "CLS_IGNR"
  55 };
  56
  57 /* We only need a valid sta if user configured a minimum rssi_threshold. */
  58 static bool rssi_threshold_check(struct ieee80211_sub_if_data *sdata,
  59                                  struct sta_info *sta)
  60 {
  61         s32 rssi_threshold = sdata->u.mesh.mshcfg.rssi_threshold;
  62         return rssi_threshold == 0 ||
  63                (sta &&
  64                 (s8)-ewma_signal_read(&sta->rx_stats_avg.signal) >
  65                                                 rssi_threshold);
  66 }
  67
  68 /**
  69  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  70  *
  71  * @sta: mesh peer link to restart
  72  *
  73  * Locking: this function must be called holding sta->mesh->plink_lock
  74  */
  75 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  76 {
  77         lockdep_assert_held(&sta->mesh->plink_lock);
  78         sta->mesh->plink_state = NL80211_PLINK_LISTEN;
  79         sta->mesh->llid = sta->mesh->plid = sta->mesh->reason = 0;
  80         sta->mesh->plink_retries = 0;
  81 }
  82
  83 /*
  84  * mesh_set_short_slot_time - enable / disable ERP short slot time.
  85  *
  86  * The standard indirectly mandates mesh STAs to turn off short slot time by
  87  * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
  88  * can't be sneaky about it. Enable short slot time if all mesh STAs in the
  89  * MBSS support ERP rates.
  90  *
  91  * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
  92  */
  93 static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
  94 {
  95         struct ieee80211_local *local = sdata->local;
  96         struct ieee80211_supported_band *sband;
  97         struct sta_info *sta;
  98         u32 erp_rates = 0, changed = 0;
  99         int i;
 100         bool short_slot = false;
 101
 102         sband = ieee80211_get_sband(sdata);
 103         if (!sband)
 104                 return changed;
 105
 106         if (sband->band == NL80211_BAND_5GHZ) {
 107                 /* (IEEE 802.11-2012 19.4.5) */
 108                 short_slot = true;
 109                 goto out;
 110         } else if (sband->band != NL80211_BAND_2GHZ) {
 111                 goto out;
 112         }
 113
 114         for (i = 0; i < sband->n_bitrates; i++)
 115                 if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
 116                         erp_rates |= BIT(i);
 117
 118         if (!erp_rates)
 119                 goto out;
 120
 121         rcu_read_lock();
 122         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 123                 if (sdata != sta->sdata ||
 124                     sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 125                         continue;
 126
 127                 short_slot = false;
 128                 if (erp_rates & sta->sta.supp_rates[sband->band])
 129                         short_slot = true;
 130                  else
 131                         break;
 132         }
 133         rcu_read_unlock();
 134
 135 out:
 136         if (sdata->vif.bss_conf.use_short_slot != short_slot) {
 137                 sdata->vif.bss_conf.use_short_slot = short_slot;
 138                 changed = BSS_CHANGED_ERP_SLOT;
 139                 mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
 140                         sdata->vif.addr, short_slot);
 141         }
 142         return changed;
 143 }
 144
 145 /**
 146  * mesh_set_ht_prot_mode - set correct HT protection mode
 147  *
 148  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 149  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 150  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 151  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 152  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 153  * HT20 peer is present. Otherwise no-protection mode is selected.
 154  */
 155 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 156 {
 157         struct ieee80211_local *local = sdata->local;
 158         struct sta_info *sta;
 159         u16 ht_opmode;
 160         bool non_ht_sta = false, ht20_sta = false;
 161
 162         switch (sdata->vif.bss_conf.chandef.width) {
 163         case NL80211_CHAN_WIDTH_20_NOHT:
 164         case NL80211_CHAN_WIDTH_5:
 165         case NL80211_CHAN_WIDTH_10:
 166                 return 0;
 167         default:
 168                 break;
 169         }
 170
 171         rcu_read_lock();
 172         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 173                 if (sdata != sta->sdata ||
 174                     sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 175                         continue;
 176
 177                 if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
 178                         continue;
 179
 180                 if (!sta->sta.ht_cap.ht_supported) {
 181                         mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
 182                                        sta->sta.addr);
 183                         non_ht_sta = true;
 184                         break;
 185                 }
 186
 187                 mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
 188                 ht20_sta = true;
 189         }
 190         rcu_read_unlock();
 191
 192         if (non_ht_sta)
 193                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 194         else if (ht20_sta &&
 195                  sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
 196                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 197         else
 198                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 199
 200         if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
 201                 return 0;
 202
 203         sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 204         sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 205         mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
 206         return BSS_CHANGED_HT;
 207 }
 208
 209 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 210                                struct sta_info *sta,
 211                                enum ieee80211_self_protected_actioncode action,
 212                                u8 *da, u16 llid, u16 plid, u16 reason)
 213 {
 214         struct ieee80211_local *local = sdata->local;
 215         struct sk_buff *skb;
 216         struct ieee80211_tx_info *info;
 217         struct ieee80211_mgmt *mgmt;
 218         bool include_plid = false;
 219         u16 peering_proto = 0;
 220         u8 *pos, ie_len = 4;
 221         int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.self_prot);
 222         int err = -ENOMEM;
 223
 224         skb = dev_alloc_skb(local->tx_headroom +
 225                             hdr_len +
 226                             2 + /* capability info */
 227                             2 + /* AID */
 228                             2 + 8 + /* supported rates */
 229                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 230                             2 + sdata->u.mesh.mesh_id_len +
 231                             2 + sizeof(struct ieee80211_meshconf_ie) +
 232                             2 + sizeof(struct ieee80211_ht_cap) +
 233                             2 + sizeof(struct ieee80211_ht_operation) +
 234                             2 + sizeof(struct ieee80211_vht_cap) +
 235                             2 + sizeof(struct ieee80211_vht_operation) +
 236                             2 + 8 + /* peering IE */
 237                             sdata->u.mesh.ie_len);
 238         if (!skb)
 239                 return err;
 240         info = IEEE80211_SKB_CB(skb);
 241         skb_reserve(skb, local->tx_headroom);
 242         mgmt = skb_put_zero(skb, hdr_len);
 243         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 244                                           IEEE80211_STYPE_ACTION);
 245         memcpy(mgmt->da, da, ETH_ALEN);
 246         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 247         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 248         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 249         mgmt->u.action.u.self_prot.action_code = action;
 250
 251         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 252                 struct ieee80211_supported_band *sband;
 253                 enum nl80211_band band;
 254
 255                 sband = ieee80211_get_sband(sdata);
 256                 if (!sband) {
 257                         err = -EINVAL;
 258                         goto free;
 259                 }
 260                 band = sband->band;
 261
 262                 /* capability info */
 263                 pos = skb_put_zero(skb, 2);
 264                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 265                         /* AID */
 266                         pos = skb_put(skb, 2);
 267                         put_unaligned_le16(sta->sta.aid, pos);
 268                 }
 269                 if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
 270                     ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
 271                     mesh_add_rsn_ie(sdata, skb) ||
 272                     mesh_add_meshid_ie(sdata, skb) ||
 273                     mesh_add_meshconf_ie(sdata, skb))
 274                         goto free;
 275         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 276                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
 277                 if (mesh_add_meshid_ie(sdata, skb))
 278                         goto free;
 279         }
 280
 281         /* Add Mesh Peering Management element */
 282         switch (action) {
 283         case WLAN_SP_MESH_PEERING_OPEN:
 284                 break;
 285         case WLAN_SP_MESH_PEERING_CONFIRM:
 286                 ie_len += 2;
 287                 include_plid = true;
 288                 break;
 289         case WLAN_SP_MESH_PEERING_CLOSE:
 290                 if (plid) {
 291                         ie_len += 2;
 292                         include_plid = true;
 293                 }
 294                 ie_len += 2;    /* reason code */
 295                 break;
 296         default:
 297                 err = -EINVAL;
 298                 goto free;
 299         }
 300
 301         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 302                 goto free;
 303
 304         pos = skb_put(skb, 2 + ie_len);
 305         *pos++ = WLAN_EID_PEER_MGMT;
 306         *pos++ = ie_len;
 307         memcpy(pos, &peering_proto, 2);
 308         pos += 2;
 309         put_unaligned_le16(llid, pos);
 310         pos += 2;
 311         if (include_plid) {
 312                 put_unaligned_le16(plid, pos);
 313                 pos += 2;
 314         }
 315         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 316                 put_unaligned_le16(reason, pos);
 317                 pos += 2;
 318         }
 319
 320         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 321                 if (mesh_add_ht_cap_ie(sdata, skb) ||
 322                     mesh_add_ht_oper_ie(sdata, skb) ||
 323                     mesh_add_vht_cap_ie(sdata, skb) ||
 324                     mesh_add_vht_oper_ie(sdata, skb))
 325                         goto free;
 326         }
 327
 328         if (mesh_add_vendor_ies(sdata, skb))
 329                 goto free;
 330
 331         ieee80211_tx_skb(sdata, skb);
 332         return 0;
 333 free:
 334         kfree_skb(skb);
 335         return err;
 336 }
 337
 338 /**
 339  * __mesh_plink_deactivate - deactivate mesh peer link
 340  *
 341  * @sta: mesh peer link to deactivate
 342  *
 343  * Mesh paths with this peer as next hop should be flushed
 344  * by the caller outside of plink_lock.
 345  *
 346  * Returns beacon changed flag if the beacon content changed.
 347  *
 348  * Locking: the caller must hold sta->mesh->plink_lock
 349  */
 350 static u32 __mesh_plink_deactivate(struct sta_info *sta)
 351 {
 352         struct ieee80211_sub_if_data *sdata = sta->sdata;
 353         u32 changed = 0;
 354
 355         lockdep_assert_held(&sta->mesh->plink_lock);
 356
 357         if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
 358                 changed = mesh_plink_dec_estab_count(sdata);
 359         sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 360
 361         ieee80211_mps_sta_status_update(sta);
 362         changed |= ieee80211_mps_set_sta_local_pm(sta,
 363                         NL80211_MESH_POWER_UNKNOWN);
 364
 365         return changed;
 366 }
 367
 368 /**
 369  * mesh_plink_deactivate - deactivate mesh peer link
 370  *
 371  * @sta: mesh peer link to deactivate
 372  *
 373  * All mesh paths with this peer as next hop will be flushed
 374  */
 375 u32 mesh_plink_deactivate(struct sta_info *sta)
 376 {
 377         struct ieee80211_sub_if_data *sdata = sta->sdata;
 378         u32 changed;
 379
 380         spin_lock_bh(&sta->mesh->plink_lock);
 381         changed = __mesh_plink_deactivate(sta);
 382
 383         if (!sdata->u.mesh.user_mpm) {
 384                 sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
 385                 mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
 386                                     sta->sta.addr, sta->mesh->llid,
 387                                     sta->mesh->plid, sta->mesh->reason);
 388         }
 389         spin_unlock_bh(&sta->mesh->plink_lock);
 390         if (!sdata->u.mesh.user_mpm)
 391                 del_timer_sync(&sta->mesh->plink_timer);
 392         mesh_path_flush_by_nexthop(sta);
 393
 394         /* make sure no readers can access nexthop sta from here on */
 395         synchronize_net();
 396
 397         return changed;
 398 }
 399
 400 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
 401                                struct sta_info *sta,
 402                                struct ieee802_11_elems *elems)
 403 {
 404         struct ieee80211_local *local = sdata->local;
 405         struct ieee80211_supported_band *sband;
 406         u32 rates, basic_rates = 0, changed = 0;
 407         enum ieee80211_sta_rx_bandwidth bw = sta->sta.bandwidth;
 408
 409         sband = ieee80211_get_sband(sdata);
 410         if (!sband)
 411                 return;
 412
 413         rates = ieee80211_sta_get_rates(sdata, elems, sband->band,
 414                                         &basic_rates);
 415
 416         spin_lock_bh(&sta->mesh->plink_lock);
 417         sta->rx_stats.last_rx = jiffies;
 418
 419         /* rates and capabilities don't change during peering */
 420         if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
 421             sta->mesh->processed_beacon)
 422                 goto out;
 423         sta->mesh->processed_beacon = true;
 424
 425         if (sta->sta.supp_rates[sband->band] != rates)
 426                 changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
 427         sta->sta.supp_rates[sband->band] = rates;
 428
 429         if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 430                                               elems->ht_cap_elem, sta))
 431                 changed |= IEEE80211_RC_BW_CHANGED;
 432
 433         ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
 434                                             elems->vht_cap_elem, sta);
 435
 436         if (bw != sta->sta.bandwidth)
 437                 changed |= IEEE80211_RC_BW_CHANGED;
 438
 439         /* HT peer is operating 20MHz-only */
 440         if (elems->ht_operation &&
 441             !(elems->ht_operation->ht_param &
 442               IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
 443                 if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
 444                         changed |= IEEE80211_RC_BW_CHANGED;
 445                 sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
 446         }
 447
 448         if (!test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
 449                 rate_control_rate_init(sta);
 450         else
 451                 rate_control_rate_update(local, sband, sta, changed);
 452 out:
 453         spin_unlock_bh(&sta->mesh->plink_lock);
 454 }
 455
 456 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
 457 {
 458         struct sta_info *sta;
 459         unsigned long *aid_map;
 460         int aid;
 461
 462         aid_map = kcalloc(BITS_TO_LONGS(IEEE80211_MAX_AID + 1),
 463                           sizeof(*aid_map), GFP_KERNEL);
 464         if (!aid_map)
 465                 return -ENOMEM;
 466
 467         /* reserve aid 0 for mcast indication */
 468         __set_bit(0, aid_map);
 469
 470         rcu_read_lock();
 471         list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
 472                 __set_bit(sta->sta.aid, aid_map);
 473         rcu_read_unlock();
 474
 475         aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
 476         kfree(aid_map);
 477
 478         if (aid > IEEE80211_MAX_AID)
 479                 return -ENOBUFS;
 480
 481         return aid;
 482 }
 483
 484 static struct sta_info *
 485 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
 486 {
 487         struct sta_info *sta;
 488         int aid;
 489
 490         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
 491                 return NULL;
 492
 493         aid = mesh_allocate_aid(sdata);
 494         if (aid < 0)
 495                 return NULL;
 496
 497         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 498         if (!sta)
 499                 return NULL;
 500
 501         sta->mesh->plink_state = NL80211_PLINK_LISTEN;
 502         sta->sta.wme = true;
 503         sta->sta.aid = aid;
 504
 505         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 506         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 507         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 508
 509         return sta;
 510 }
 511
 512 static struct sta_info *
 513 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
 514                     struct ieee802_11_elems *elems,
 515                     struct ieee80211_rx_status *rx_status)
 516 {
 517         struct sta_info *sta = NULL;
 518
 519         /* Userspace handles station allocation */
 520         if (sdata->u.mesh.user_mpm ||
 521             sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
 522                 if (mesh_peer_accepts_plinks(elems) &&
 523                     mesh_plink_availables(sdata)) {
 524                         int sig = 0;
 525
 526                         if (ieee80211_hw_check(&sdata->local->hw, SIGNAL_DBM))
 527                                 sig = rx_status->signal;
 528
 529                         cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 530                                                            elems->ie_start,
 531                                                            elems->total_len,
 532                                                            sig, GFP_KERNEL);
 533                 }
 534         } else
 535                 sta = __mesh_sta_info_alloc(sdata, addr);
 536
 537         return sta;
 538 }
 539
 540 /*
 541  * mesh_sta_info_get - return mesh sta info entry for @addr.
 542  *
 543  * @sdata: local meshif
 544  * @addr: peer's address
 545  * @elems: IEs from beacon or mesh peering frame.
 546  * @rx_status: rx status for the frame for signal reporting
 547  *
 548  * Return existing or newly allocated sta_info under RCU read lock.
 549  * (re)initialize with given IEs.
 550  */
 551 static struct sta_info *
 552 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
 553                   u8 *addr, struct ieee802_11_elems *elems,
 554                   struct ieee80211_rx_status *rx_status) __acquires(RCU)
 555 {
 556         struct sta_info *sta = NULL;
 557
 558         rcu_read_lock();
 559         sta = sta_info_get(sdata, addr);
 560         if (sta) {
 561                 mesh_sta_info_init(sdata, sta, elems);
 562         } else {
 563                 rcu_read_unlock();
 564                 /* can't run atomic */
 565                 sta = mesh_sta_info_alloc(sdata, addr, elems, rx_status);
 566                 if (!sta) {
 567                         rcu_read_lock();
 568                         return NULL;
 569                 }
 570
 571                 mesh_sta_info_init(sdata, sta, elems);
 572
 573                 if (sta_info_insert_rcu(sta))
 574                         return NULL;
 575         }
 576
 577         return sta;
 578 }
 579
 580 /*
 581  * mesh_neighbour_update - update or initialize new mesh neighbor.
 582  *
 583  * @sdata: local meshif
 584  * @addr: peer's address
 585  * @elems: IEs from beacon or mesh peering frame
 586  * @rx_status: rx status for the frame for signal reporting
 587  *
 588  * Initiates peering if appropriate.
 589  */
 590 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 591                            u8 *hw_addr,
 592                            struct ieee802_11_elems *elems,
 593                            struct ieee80211_rx_status *rx_status)
 594 {
 595         struct sta_info *sta;
 596         u32 changed = 0;
 597
 598         sta = mesh_sta_info_get(sdata, hw_addr, elems, rx_status);
 599         if (!sta)
 600                 goto out;
 601
 602         sta->mesh->connected_to_gate = elems->mesh_config->meshconf_form &
 603                 IEEE80211_MESHCONF_FORM_CONNECTED_TO_GATE;
 604
 605         if (mesh_peer_accepts_plinks(elems) &&
 606             sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
 607             sdata->u.mesh.accepting_plinks &&
 608             sdata->u.mesh.mshcfg.auto_open_plinks &&
 609             rssi_threshold_check(sdata, sta))
 610                 changed = mesh_plink_open(sta);
 611
 612         ieee80211_mps_frame_release(sta, elems);
 613 out:
 614         rcu_read_unlock();
 615         ieee80211_mbss_info_change_notify(sdata, changed);
 616 }
 617
 618 void mesh_plink_timer(struct timer_list *t)
 619 {
 620         struct mesh_sta *mesh = from_timer(mesh, t, plink_timer);
 621         struct sta_info *sta;
 622         u16 reason = 0;
 623         struct ieee80211_sub_if_data *sdata;
 624         struct mesh_config *mshcfg;
 625         enum ieee80211_self_protected_actioncode action = 0;
 626
 627         /*
 628          * This STA is valid because sta_info_destroy() will
 629          * del_timer_sync() this timer after having made sure
 630          * it cannot be readded (by deleting the plink.)
 631          */
 632         sta = mesh->plink_sta;
 633
 634         if (sta->sdata->local->quiescing)
 635                 return;
 636
 637         spin_lock_bh(&sta->mesh->plink_lock);
 638
 639         /* If a timer fires just before a state transition on another CPU,
 640          * we may have already extended the timeout and changed state by the
 641          * time we've acquired the lock and arrived  here.  In that case,
 642          * skip this timer and wait for the new one.
 643          */
 644         if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
 645                 mpl_dbg(sta->sdata,
 646                         "Ignoring timer for %pM in state %s (timer adjusted)",
 647                         sta->sta.addr, mplstates[sta->mesh->plink_state]);
 648                 spin_unlock_bh(&sta->mesh->plink_lock);
 649                 return;
 650         }
 651
 652         /* del_timer() and handler may race when entering these states */
 653         if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
 654             sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
 655                 mpl_dbg(sta->sdata,
 656                         "Ignoring timer for %pM in state %s (timer deleted)",
 657                         sta->sta.addr, mplstates[sta->mesh->plink_state]);
 658                 spin_unlock_bh(&sta->mesh->plink_lock);
 659                 return;
 660         }
 661
 662         mpl_dbg(sta->sdata,
 663                 "Mesh plink timer for %pM fired on state %s\n",
 664                 sta->sta.addr, mplstates[sta->mesh->plink_state]);
 665         sdata = sta->sdata;
 666         mshcfg = &sdata->u.mesh.mshcfg;
 667
 668         switch (sta->mesh->plink_state) {
 669         case NL80211_PLINK_OPN_RCVD:
 670         case NL80211_PLINK_OPN_SNT:
 671                 /* retry timer */
 672                 if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
 673                         u32 rand;
 674                         mpl_dbg(sta->sdata,
 675                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 676                                 sta->sta.addr, sta->mesh->plink_retries,
 677                                 sta->mesh->plink_timeout);
 678                         get_random_bytes(&rand, sizeof(u32));
 679                         sta->mesh->plink_timeout = sta->mesh->plink_timeout +
 680                                              rand % sta->mesh->plink_timeout;
 681                         ++sta->mesh->plink_retries;
 682                         mod_plink_timer(sta, sta->mesh->plink_timeout);
 683                         action = WLAN_SP_MESH_PEERING_OPEN;
 684                         break;
 685                 }
 686                 reason = WLAN_REASON_MESH_MAX_RETRIES;
 687                 /* fall through */
 688         case NL80211_PLINK_CNF_RCVD:
 689                 /* confirm timer */
 690                 if (!reason)
 691                         reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
 692                 sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 693                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 694                 action = WLAN_SP_MESH_PEERING_CLOSE;
 695                 break;
 696         case NL80211_PLINK_HOLDING:
 697                 /* holding timer */
 698                 del_timer(&sta->mesh->plink_timer);
 699                 mesh_plink_fsm_restart(sta);
 700                 break;
 701         default:
 702                 break;
 703         }
 704         spin_unlock_bh(&sta->mesh->plink_lock);
 705         if (action)
 706                 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 707                                     sta->mesh->llid, sta->mesh->plid, reason);
 708 }
 709
 710 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
 711 {
 712         sta->mesh->plink_timeout = timeout;
 713         mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
 714 }
 715
 716 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
 717                         u16 llid)
 718 {
 719         struct ieee80211_local *local = sdata->local;
 720         bool in_use = false;
 721         struct sta_info *sta;
 722
 723         rcu_read_lock();
 724         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 725                 if (sdata != sta->sdata)
 726                         continue;
 727
 728                 if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
 729                         in_use = true;
 730                         break;
 731                 }
 732         }
 733         rcu_read_unlock();
 734
 735         return in_use;
 736 }
 737
 738 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 739 {
 740         u16 llid;
 741
 742         do {
 743                 get_random_bytes(&llid, sizeof(llid));
 744         } while (llid_in_use(sdata, llid));
 745
 746         return llid;
 747 }
 748
 749 u32 mesh_plink_open(struct sta_info *sta)
 750 {
 751         struct ieee80211_sub_if_data *sdata = sta->sdata;
 752         u32 changed;
 753
 754         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 755                 return 0;
 756
 757         spin_lock_bh(&sta->mesh->plink_lock);
 758         sta->mesh->llid = mesh_get_new_llid(sdata);
 759         if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
 760             sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
 761                 spin_unlock_bh(&sta->mesh->plink_lock);
 762                 return 0;
 763         }
 764         sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
 765         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 766         spin_unlock_bh(&sta->mesh->plink_lock);
 767         mpl_dbg(sdata,
 768                 "Mesh plink: starting establishment with %pM\n",
 769                 sta->sta.addr);
 770
 771         /* set the non-peer mode to active during peering */
 772         changed = ieee80211_mps_local_status_update(sdata);
 773
 774         mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
 775                             sta->sta.addr, sta->mesh->llid, 0, 0);
 776         return changed;
 777 }
 778
 779 u32 mesh_plink_block(struct sta_info *sta)
 780 {
 781         u32 changed;
 782
 783         spin_lock_bh(&sta->mesh->plink_lock);
 784         changed = __mesh_plink_deactivate(sta);
 785         sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 786         spin_unlock_bh(&sta->mesh->plink_lock);
 787         mesh_path_flush_by_nexthop(sta);
 788
 789         return changed;
 790 }
 791
 792 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
 793                              struct sta_info *sta,
 794                              enum plink_event event)
 795 {
 796         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 797         u16 reason = (event == CLS_ACPT) ?
 798                      WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
 799
 800         sta->mesh->reason = reason;
 801         sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 802         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 803 }
 804
 805 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
 806                                 struct sta_info *sta)
 807 {
 808         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 809         u32 changed = 0;
 810
 811         del_timer(&sta->mesh->plink_timer);
 812         sta->mesh->plink_state = NL80211_PLINK_ESTAB;
 813         changed |= mesh_plink_inc_estab_count(sdata);
 814         changed |= mesh_set_ht_prot_mode(sdata);
 815         changed |= mesh_set_short_slot_time(sdata);
 816         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
 817         ieee80211_mps_sta_status_update(sta);
 818         changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
 819         return changed;
 820 }
 821
 822 /**
 823  * mesh_plink_fsm - step @sta MPM based on @event
 824  *
 825  * @sdata: interface
 826  * @sta: mesh neighbor
 827  * @event: peering event
 828  *
 829  * Return: changed MBSS flags
 830  */
 831 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
 832                           struct sta_info *sta, enum plink_event event)
 833 {
 834         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 835         enum ieee80211_self_protected_actioncode action = 0;
 836         u32 changed = 0;
 837         bool flush = false;
 838
 839         mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
 840                 mplstates[sta->mesh->plink_state], mplevents[event]);
 841
 842         spin_lock_bh(&sta->mesh->plink_lock);
 843         switch (sta->mesh->plink_state) {
 844         case NL80211_PLINK_LISTEN:
 845                 switch (event) {
 846                 case CLS_ACPT:
 847                         mesh_plink_fsm_restart(sta);
 848                         break;
 849                 case OPN_ACPT:
 850                         sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 851                         sta->mesh->llid = mesh_get_new_llid(sdata);
 852                         mesh_plink_timer_set(sta,
 853                                              mshcfg->dot11MeshRetryTimeout);
 854
 855                         /* set the non-peer mode to active during peering */
 856                         changed |= ieee80211_mps_local_status_update(sdata);
 857                         action = WLAN_SP_MESH_PEERING_OPEN;
 858                         break;
 859                 default:
 860                         break;
 861                 }
 862                 break;
 863         case NL80211_PLINK_OPN_SNT:
 864                 switch (event) {
 865                 case OPN_RJCT:
 866                 case CNF_RJCT:
 867                 case CLS_ACPT:
 868                         mesh_plink_close(sdata, sta, event);
 869                         action = WLAN_SP_MESH_PEERING_CLOSE;
 870                         break;
 871                 case OPN_ACPT:
 872                         /* retry timer is left untouched */
 873                         sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 874                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 875                         break;
 876                 case CNF_ACPT:
 877                         sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
 878                         mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
 879                         break;
 880                 default:
 881                         break;
 882                 }
 883                 break;
 884         case NL80211_PLINK_OPN_RCVD:
 885                 switch (event) {
 886                 case OPN_RJCT:
 887                 case CNF_RJCT:
 888                 case CLS_ACPT:
 889                         mesh_plink_close(sdata, sta, event);
 890                         action = WLAN_SP_MESH_PEERING_CLOSE;
 891                         break;
 892                 case OPN_ACPT:
 893                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 894                         break;
 895                 case CNF_ACPT:
 896                         changed |= mesh_plink_establish(sdata, sta);
 897                         break;
 898                 default:
 899                         break;
 900                 }
 901                 break;
 902         case NL80211_PLINK_CNF_RCVD:
 903                 switch (event) {
 904                 case OPN_RJCT:
 905                 case CNF_RJCT:
 906                 case CLS_ACPT:
 907                         mesh_plink_close(sdata, sta, event);
 908                         action = WLAN_SP_MESH_PEERING_CLOSE;
 909                         break;
 910                 case OPN_ACPT:
 911                         changed |= mesh_plink_establish(sdata, sta);
 912                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 913                         break;
 914                 default:
 915                         break;
 916                 }
 917                 break;
 918         case NL80211_PLINK_ESTAB:
 919                 switch (event) {
 920                 case CLS_ACPT:
 921                         changed |= __mesh_plink_deactivate(sta);
 922                         changed |= mesh_set_ht_prot_mode(sdata);
 923                         changed |= mesh_set_short_slot_time(sdata);
 924                         mesh_plink_close(sdata, sta, event);
 925                         action = WLAN_SP_MESH_PEERING_CLOSE;
 926                         flush = true;
 927                         break;
 928                 case OPN_ACPT:
 929                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 930                         break;
 931                 default:
 932                         break;
 933                 }
 934                 break;
 935         case NL80211_PLINK_HOLDING:
 936                 switch (event) {
 937                 case CLS_ACPT:
 938                         del_timer(&sta->mesh->plink_timer);
 939                         mesh_plink_fsm_restart(sta);
 940                         break;
 941                 case OPN_ACPT:
 942                 case CNF_ACPT:
 943                 case OPN_RJCT:
 944                 case CNF_RJCT:
 945                         action = WLAN_SP_MESH_PEERING_CLOSE;
 946                         break;
 947                 default:
 948                         break;
 949                 }
 950                 break;
 951         default:
 952                 /* should not get here, PLINK_BLOCKED is dealt with at the
 953                  * beginning of the function
 954                  */
 955                 break;
 956         }
 957         spin_unlock_bh(&sta->mesh->plink_lock);
 958         if (flush)
 959                 mesh_path_flush_by_nexthop(sta);
 960         if (action) {
 961                 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 962                                     sta->mesh->llid, sta->mesh->plid,
 963                                     sta->mesh->reason);
 964
 965                 /* also send confirm in open case */
 966                 if (action == WLAN_SP_MESH_PEERING_OPEN) {
 967                         mesh_plink_frame_tx(sdata, sta,
 968                                             WLAN_SP_MESH_PEERING_CONFIRM,
 969                                             sta->sta.addr, sta->mesh->llid,
 970                                             sta->mesh->plid, 0);
 971                 }
 972         }
 973
 974         return changed;
 975 }
 976
 977 /*
 978  * mesh_plink_get_event - get correct MPM event
 979  *
 980  * @sdata: interface
 981  * @sta: peer, leave NULL if processing a frame from a new suitable peer
 982  * @elems: peering management IEs
 983  * @ftype: frame type
 984  * @llid: peer's peer link ID
 985  * @plid: peer's local link ID
 986  *
 987  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
 988  * an error.
 989  */
 990 static enum plink_event
 991 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
 992                      struct sta_info *sta,
 993                      struct ieee802_11_elems *elems,
 994                      enum ieee80211_self_protected_actioncode ftype,
 995                      u16 llid, u16 plid)
 996 {
 997         enum plink_event event = PLINK_UNDEFINED;
 998         u8 ie_len = elems->peering_len;
 999         bool matches_local;
1000
1001         matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
1002                          mesh_matches_local(sdata, elems));
1003
1004         /* deny open request from non-matching peer */
1005         if (!matches_local && !sta) {
1006                 event = OPN_RJCT;
1007                 goto out;
1008         }
1009
1010         if (!sta) {
1011                 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
1012                         mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
1013                         goto out;
1014                 }
1015                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
1016                 if (!mesh_plink_free_count(sdata)) {
1017                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
1018                         goto out;
1019                 }
1020
1021                 /* new matching peer */
1022                 event = OPN_ACPT;
1023                 goto out;
1024         } else {
1025                 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
1026                         mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
1027                         goto out;
1028                 }
1029                 if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
1030                         goto out;
1031         }
1032
1033         switch (ftype) {
1034         case WLAN_SP_MESH_PEERING_OPEN:
1035                 if (!matches_local)
1036                         event = OPN_RJCT;
1037                 if (!mesh_plink_free_count(sdata) ||
1038                     (sta->mesh->plid && sta->mesh->plid != plid))
1039                         event = OPN_IGNR;
1040                 else
1041                         event = OPN_ACPT;
1042                 break;
1043         case WLAN_SP_MESH_PEERING_CONFIRM:
1044                 if (!matches_local)
1045                         event = CNF_RJCT;
1046                 if (!mesh_plink_free_count(sdata) ||
1047                     sta->mesh->llid != llid ||
1048                     (sta->mesh->plid && sta->mesh->plid != plid))
1049                         event = CNF_IGNR;
1050                 else
1051                         event = CNF_ACPT;
1052                 break;
1053         case WLAN_SP_MESH_PEERING_CLOSE:
1054                 if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1055                         /* Do not check for llid or plid. This does not
1056                          * follow the standard but since multiple plinks
1057                          * per sta are not supported, it is necessary in
1058                          * order to avoid a livelock when MP A sees an
1059                          * establish peer link to MP B but MP B does not
1060                          * see it. This can be caused by a timeout in
1061                          * B's peer link establishment or B beign
1062                          * restarted.
1063                          */
1064                         event = CLS_ACPT;
1065                 else if (sta->mesh->plid != plid)
1066                         event = CLS_IGNR;
1067                 else if (ie_len == 8 && sta->mesh->llid != llid)
1068                         event = CLS_IGNR;
1069                 else
1070                         event = CLS_ACPT;
1071                 break;
1072         default:
1073                 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1074                 break;
1075         }
1076
1077 out:
1078         return event;
1079 }
1080
1081 static void
1082 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1083                          struct ieee80211_mgmt *mgmt,
1084                          struct ieee802_11_elems *elems,
1085                          struct ieee80211_rx_status *rx_status)
1086 {
1087
1088         struct sta_info *sta;
1089         enum plink_event event;
1090         enum ieee80211_self_protected_actioncode ftype;
1091         u32 changed = 0;
1092         u8 ie_len = elems->peering_len;
1093         u16 plid, llid = 0;
1094
1095         if (!elems->peering) {
1096                 mpl_dbg(sdata,
1097                         "Mesh plink: missing necessary peer link ie\n");
1098                 return;
1099         }
1100
1101         if (elems->rsn_len &&
1102             sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1103                 mpl_dbg(sdata,
1104                         "Mesh plink: can't establish link with secure peer\n");
1105                 return;
1106         }
1107
1108         ftype = mgmt->u.action.u.self_prot.action_code;
1109         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1110             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1111             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1112                                                         && ie_len != 8)) {
1113                 mpl_dbg(sdata,
1114                         "Mesh plink: incorrect plink ie length %d %d\n",
1115                         ftype, ie_len);
1116                 return;
1117         }
1118
1119         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1120             (!elems->mesh_id || !elems->mesh_config)) {
1121                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1122                 return;
1123         }
1124         /* Note the lines below are correct, the llid in the frame is the plid
1125          * from the point of view of this host.
1126          */
1127         plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1128         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1129             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1130                 llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1131
1132         /* WARNING: Only for sta pointer, is dropped & re-acquired */
1133         rcu_read_lock();
1134
1135         sta = sta_info_get(sdata, mgmt->sa);
1136
1137         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1138             !rssi_threshold_check(sdata, sta)) {
1139                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1140                         mgmt->sa);
1141                 goto unlock_rcu;
1142         }
1143
1144         /* Now we will figure out the appropriate event... */
1145         event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1146
1147         if (event == OPN_ACPT) {
1148                 rcu_read_unlock();
1149                 /* allocate sta entry if necessary and update info */
1150                 sta = mesh_sta_info_get(sdata, mgmt->sa, elems, rx_status);
1151                 if (!sta) {
1152                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1153                         goto unlock_rcu;
1154                 }
1155                 sta->mesh->plid = plid;
1156         } else if (!sta && event == OPN_RJCT) {
1157                 mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1158                                     mgmt->sa, 0, plid,
1159                                     WLAN_REASON_MESH_CONFIG);
1160                 goto unlock_rcu;
1161         } else if (!sta || event == PLINK_UNDEFINED) {
1162                 /* something went wrong */
1163                 goto unlock_rcu;
1164         }
1165
1166         if (event == CNF_ACPT) {
1167                 /* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1168                 if (!sta->mesh->plid)
1169                         sta->mesh->plid = plid;
1170
1171                 sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1172         }
1173
1174         changed |= mesh_plink_fsm(sdata, sta, event);
1175
1176 unlock_rcu:
1177         rcu_read_unlock();
1178
1179         if (changed)
1180                 ieee80211_mbss_info_change_notify(sdata, changed);
1181 }
1182
1183 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1184                          struct ieee80211_mgmt *mgmt, size_t len,
1185                          struct ieee80211_rx_status *rx_status)
1186 {
1187         struct ieee802_11_elems elems;
1188         size_t baselen;
1189         u8 *baseaddr;
1190
1191         /* need action_code, aux */
1192         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1193                 return;
1194
1195         if (sdata->u.mesh.user_mpm)
1196                 /* userspace must register for these */
1197                 return;
1198
1199         if (is_multicast_ether_addr(mgmt->da)) {
1200                 mpl_dbg(sdata,
1201                         "Mesh plink: ignore frame from multicast address\n");
1202                 return;
1203         }
1204
1205         baseaddr = mgmt->u.action.u.self_prot.variable;
1206         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1207         if (mgmt->u.action.u.self_prot.action_code ==
1208                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
1209                 baseaddr += 4;
1210                 baselen += 4;
1211
1212                 if (baselen > len)
1213                         return;
1214         }
1215         ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems,
1216                                mgmt->bssid, NULL);
1217         mesh_process_plink_frame(sdata, mgmt, &elems, rx_status);
1218 }