net/mac80211/mesh_plink.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9 #include <linux/gfp.h>
  10 #include <linux/kernel.h>
  11 #include <linux/random.h>
  12 #include "ieee80211_i.h"
  13 #include "rate.h"
  14 #include "mesh.h"
  15
  16 #define PLINK_GET_LLID(p) (p + 2)
  17 #define PLINK_GET_PLID(p) (p + 4)
  18
  19 #define mod_plink_timer(s, t) (mod_timer(&s->plink_timer, \
  20                                 jiffies + HZ * t / 1000))
  21
  22 #define dot11MeshMaxRetries(s) (s->u.mesh.mshcfg.dot11MeshMaxRetries)
  23 #define dot11MeshRetryTimeout(s) (s->u.mesh.mshcfg.dot11MeshRetryTimeout)
  24 #define dot11MeshConfirmTimeout(s) (s->u.mesh.mshcfg.dot11MeshConfirmTimeout)
  25 #define dot11MeshHoldingTimeout(s) (s->u.mesh.mshcfg.dot11MeshHoldingTimeout)
  26 #define dot11MeshMaxPeerLinks(s) (s->u.mesh.mshcfg.dot11MeshMaxPeerLinks)
  27
  28 /* We only need a valid sta if user configured a minimum rssi_threshold. */
  29 #define rssi_threshold_check(sta, sdata) \
  30                 (sdata->u.mesh.mshcfg.rssi_threshold == 0 ||\
  31                 (sta && (s8) -ewma_read(&sta->avg_signal) > \
  32                 sdata->u.mesh.mshcfg.rssi_threshold))
  33
  34 enum plink_event {
  35         PLINK_UNDEFINED,
  36         OPN_ACPT,
  37         OPN_RJCT,
  38         OPN_IGNR,
  39         CNF_ACPT,
  40         CNF_RJCT,
  41         CNF_IGNR,
  42         CLS_ACPT,
  43         CLS_IGNR
  44 };
  45
  46 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
  47                 enum ieee80211_self_protected_actioncode action,
  48                 u8 *da, __le16 llid, __le16 plid, __le16 reason);
  49
  50 static inline
  51 void mesh_plink_inc_estab_count(struct ieee80211_sub_if_data *sdata)
  52 {
  53         atomic_inc(&sdata->u.mesh.mshstats.estab_plinks);
  54         mesh_accept_plinks_update(sdata);
  55 }
  56
  57 static inline
  58 void mesh_plink_dec_estab_count(struct ieee80211_sub_if_data *sdata)
  59 {
  60         atomic_dec(&sdata->u.mesh.mshstats.estab_plinks);
  61         mesh_accept_plinks_update(sdata);
  62 }
  63
  64 /**
  65  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  66  *
  67  * @sta: mesh peer link to restart
  68  *
  69  * Locking: this function must be called holding sta->lock
  70  */
  71 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  72 {
  73         sta->plink_state = NL80211_PLINK_LISTEN;
  74         sta->llid = sta->plid = sta->reason = 0;
  75         sta->plink_retries = 0;
  76 }
  77
  78 /*
  79  * Allocate mesh sta entry and insert into station table
  80  */
  81 static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
  82                                          u8 *hw_addr)
  83 {
  84         struct sta_info *sta;
  85
  86         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
  87                 return NULL;
  88
  89         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
  90         if (!sta)
  91                 return NULL;
  92
  93         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
  94         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
  95         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
  96
  97         set_sta_flag(sta, WLAN_STA_WME);
  98
  99         return sta;
 100 }
 101
 102 /*
 103  * mesh_set_ht_prot_mode - set correct HT protection mode
 104  *
 105  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 106  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 107  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 108  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 109  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 110  * HT20 peer is present. Otherwise no-protection mode is selected.
 111  */
 112 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 113 {
 114         struct ieee80211_local *local = sdata->local;
 115         struct sta_info *sta;
 116         u32 changed = 0;
 117         u16 ht_opmode;
 118         bool non_ht_sta = false, ht20_sta = false;
 119
 120         if (local->_oper_channel_type == NL80211_CHAN_NO_HT)
 121                 return 0;
 122
 123         rcu_read_lock();
 124         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 125                 if (sdata != sta->sdata ||
 126                     sta->plink_state != NL80211_PLINK_ESTAB)
 127                         continue;
 128
 129                 switch (sta->ch_type) {
 130                 case NL80211_CHAN_NO_HT:
 131                         mpl_dbg(sdata,
 132                                 "mesh_plink %pM: nonHT sta (%pM) is present\n",
 133                                 sdata->vif.addr, sta->sta.addr);
 134                         non_ht_sta = true;
 135                         goto out;
 136                 case NL80211_CHAN_HT20:
 137                         mpl_dbg(sdata,
 138                                 "mesh_plink %pM: HT20 sta (%pM) is present\n",
 139                                 sdata->vif.addr, sta->sta.addr);
 140                         ht20_sta = true;
 141                 default:
 142                         break;
 143                 }
 144         }
 145 out:
 146         rcu_read_unlock();
 147
 148         if (non_ht_sta)
 149                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 150         else if (ht20_sta && local->_oper_channel_type > NL80211_CHAN_HT20)
 151                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 152         else
 153                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 154
 155         if (sdata->vif.bss_conf.ht_operation_mode != ht_opmode) {
 156                 sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 157                 sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 158                 changed = BSS_CHANGED_HT;
 159                 mpl_dbg(sdata,
 160                         "mesh_plink %pM: protection mode changed to %d\n",
 161                         sdata->vif.addr, ht_opmode);
 162         }
 163
 164         return changed;
 165 }
 166
 167 /**
 168  * __mesh_plink_deactivate - deactivate mesh peer link
 169  *
 170  * @sta: mesh peer link to deactivate
 171  *
 172  * All mesh paths with this peer as next hop will be flushed
 173  *
 174  * Locking: the caller must hold sta->lock
 175  */
 176 static bool __mesh_plink_deactivate(struct sta_info *sta)
 177 {
 178         struct ieee80211_sub_if_data *sdata = sta->sdata;
 179         bool deactivated = false;
 180
 181         if (sta->plink_state == NL80211_PLINK_ESTAB) {
 182                 mesh_plink_dec_estab_count(sdata);
 183                 deactivated = true;
 184         }
 185         sta->plink_state = NL80211_PLINK_BLOCKED;
 186         mesh_path_flush_by_nexthop(sta);
 187
 188         return deactivated;
 189 }
 190
 191 /**
 192  * mesh_plink_deactivate - deactivate mesh peer link
 193  *
 194  * @sta: mesh peer link to deactivate
 195  *
 196  * All mesh paths with this peer as next hop will be flushed
 197  */
 198 void mesh_plink_deactivate(struct sta_info *sta)
 199 {
 200         struct ieee80211_sub_if_data *sdata = sta->sdata;
 201         bool deactivated;
 202
 203         spin_lock_bh(&sta->lock);
 204         deactivated = __mesh_plink_deactivate(sta);
 205         sta->reason = cpu_to_le16(WLAN_REASON_MESH_PEER_CANCELED);
 206         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 207                             sta->sta.addr, sta->llid, sta->plid,
 208                             sta->reason);
 209         spin_unlock_bh(&sta->lock);
 210
 211         if (deactivated)
 212                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 213 }
 214
 215 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 216                 enum ieee80211_self_protected_actioncode action,
 217                 u8 *da, __le16 llid, __le16 plid, __le16 reason) {
 218         struct ieee80211_local *local = sdata->local;
 219         struct sk_buff *skb;
 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 = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 225                       sizeof(mgmt->u.action.u.self_prot);
 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 + 8 + /* peering IE */
 238                             sdata->u.mesh.ie_len);
 239         if (!skb)
 240                 return -1;
 241         skb_reserve(skb, local->tx_headroom);
 242         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 243         memset(mgmt, 0, hdr_len);
 244         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 245                                           IEEE80211_STYPE_ACTION);
 246         memcpy(mgmt->da, da, ETH_ALEN);
 247         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 248         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 249         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 250         mgmt->u.action.u.self_prot.action_code = action;
 251
 252         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 253                 /* capability info */
 254                 pos = skb_put(skb, 2);
 255                 memset(pos, 0, 2);
 256                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 257                         /* AID */
 258                         pos = skb_put(skb, 2);
 259                         memcpy(pos + 2, &plid, 2);
 260                 }
 261                 if (ieee80211_add_srates_ie(sdata, skb, true) ||
 262                     ieee80211_add_ext_srates_ie(sdata, skb, true) ||
 263                     mesh_add_rsn_ie(skb, sdata) ||
 264                     mesh_add_meshid_ie(skb, sdata) ||
 265                     mesh_add_meshconf_ie(skb, sdata))
 266                         return -1;
 267         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 268                 if (mesh_add_meshid_ie(skb, sdata))
 269                         return -1;
 270         }
 271
 272         /* Add Mesh Peering Management element */
 273         switch (action) {
 274         case WLAN_SP_MESH_PEERING_OPEN:
 275                 break;
 276         case WLAN_SP_MESH_PEERING_CONFIRM:
 277                 ie_len += 2;
 278                 include_plid = true;
 279                 break;
 280         case WLAN_SP_MESH_PEERING_CLOSE:
 281                 if (plid) {
 282                         ie_len += 2;
 283                         include_plid = true;
 284                 }
 285                 ie_len += 2;    /* reason code */
 286                 break;
 287         default:
 288                 return -EINVAL;
 289         }
 290
 291         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 292                 return -ENOMEM;
 293
 294         pos = skb_put(skb, 2 + ie_len);
 295         *pos++ = WLAN_EID_PEER_MGMT;
 296         *pos++ = ie_len;
 297         memcpy(pos, &peering_proto, 2);
 298         pos += 2;
 299         memcpy(pos, &llid, 2);
 300         pos += 2;
 301         if (include_plid) {
 302                 memcpy(pos, &plid, 2);
 303                 pos += 2;
 304         }
 305         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 306                 memcpy(pos, &reason, 2);
 307                 pos += 2;
 308         }
 309
 310         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 311                 if (mesh_add_ht_cap_ie(skb, sdata) ||
 312                     mesh_add_ht_oper_ie(skb, sdata))
 313                         return -1;
 314         }
 315
 316         if (mesh_add_vendor_ies(skb, sdata))
 317                 return -1;
 318
 319         ieee80211_tx_skb(sdata, skb);
 320         return 0;
 321 }
 322
 323 /* mesh_peer_init - initialize new mesh peer and return resulting sta_info
 324  *
 325  * @sdata: local meshif
 326  * @addr: peer's address
 327  * @elems: IEs from beacon or mesh peering frame
 328  *
 329  * call under RCU
 330  */
 331 static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata,
 332                                        u8 *addr,
 333                                        struct ieee802_11_elems *elems)
 334 {
 335         struct ieee80211_local *local = sdata->local;
 336         enum ieee80211_band band = local->oper_channel->band;
 337         struct ieee80211_supported_band *sband;
 338         u32 rates, basic_rates = 0;
 339         struct sta_info *sta;
 340         bool insert = false;
 341
 342         sband = local->hw.wiphy->bands[band];
 343         rates = ieee80211_sta_get_rates(local, elems, band, &basic_rates);
 344
 345         sta = sta_info_get(sdata, addr);
 346         if (!sta) {
 347                 /* Userspace handles peer allocation when security is enabled */
 348                 if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
 349                         cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 350                                                            elems->ie_start,
 351                                                            elems->total_len,
 352                                                            GFP_ATOMIC);
 353                         return NULL;
 354                 }
 355
 356                 sta = mesh_plink_alloc(sdata, addr);
 357                 if (!sta)
 358                         return NULL;
 359                 insert = true;
 360         }
 361
 362         spin_lock_bh(&sta->lock);
 363         sta->last_rx = jiffies;
 364         sta->sta.supp_rates[band] = rates;
 365         if (elems->ht_cap_elem &&
 366             sdata->local->_oper_channel_type != NL80211_CHAN_NO_HT)
 367                 ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 368                                                   elems->ht_cap_elem,
 369                                                   &sta->sta.ht_cap);
 370         else
 371                 memset(&sta->sta.ht_cap, 0, sizeof(sta->sta.ht_cap));
 372
 373         if (elems->ht_operation) {
 374                 if (!(elems->ht_operation->ht_param &
 375                       IEEE80211_HT_PARAM_CHAN_WIDTH_ANY))
 376                         sta->sta.ht_cap.cap &=
 377                                             ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 378                 sta->ch_type =
 379                         ieee80211_ht_oper_to_channel_type(elems->ht_operation);
 380         }
 381
 382         rate_control_rate_init(sta);
 383         spin_unlock_bh(&sta->lock);
 384
 385         if (insert && sta_info_insert(sta))
 386                 return NULL;
 387
 388         return sta;
 389 }
 390
 391 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 392                            u8 *hw_addr,
 393                            struct ieee802_11_elems *elems)
 394 {
 395         struct sta_info *sta;
 396
 397         rcu_read_lock();
 398         sta = mesh_peer_init(sdata, hw_addr, elems);
 399         if (!sta)
 400                 goto out;
 401
 402         if (mesh_peer_accepts_plinks(elems) &&
 403             sta->plink_state == NL80211_PLINK_LISTEN &&
 404             sdata->u.mesh.accepting_plinks &&
 405             sdata->u.mesh.mshcfg.auto_open_plinks &&
 406             rssi_threshold_check(sta, sdata))
 407                 mesh_plink_open(sta);
 408
 409 out:
 410         rcu_read_unlock();
 411 }
 412
 413 static void mesh_plink_timer(unsigned long data)
 414 {
 415         struct sta_info *sta;
 416         __le16 llid, plid, reason;
 417         struct ieee80211_sub_if_data *sdata;
 418
 419         /*
 420          * This STA is valid because sta_info_destroy() will
 421          * del_timer_sync() this timer after having made sure
 422          * it cannot be readded (by deleting the plink.)
 423          */
 424         sta = (struct sta_info *) data;
 425
 426         if (sta->sdata->local->quiescing) {
 427                 sta->plink_timer_was_running = true;
 428                 return;
 429         }
 430
 431         spin_lock_bh(&sta->lock);
 432         if (sta->ignore_plink_timer) {
 433                 sta->ignore_plink_timer = false;
 434                 spin_unlock_bh(&sta->lock);
 435                 return;
 436         }
 437         mpl_dbg(sta->sdata,
 438                 "Mesh plink timer for %pM fired on state %d\n",
 439                 sta->sta.addr, sta->plink_state);
 440         reason = 0;
 441         llid = sta->llid;
 442         plid = sta->plid;
 443         sdata = sta->sdata;
 444
 445         switch (sta->plink_state) {
 446         case NL80211_PLINK_OPN_RCVD:
 447         case NL80211_PLINK_OPN_SNT:
 448                 /* retry timer */
 449                 if (sta->plink_retries < dot11MeshMaxRetries(sdata)) {
 450                         u32 rand;
 451                         mpl_dbg(sta->sdata,
 452                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 453                                 sta->sta.addr, sta->plink_retries,
 454                                 sta->plink_timeout);
 455                         get_random_bytes(&rand, sizeof(u32));
 456                         sta->plink_timeout = sta->plink_timeout +
 457                                              rand % sta->plink_timeout;
 458                         ++sta->plink_retries;
 459                         mod_plink_timer(sta, sta->plink_timeout);
 460                         spin_unlock_bh(&sta->lock);
 461                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 462                                             sta->sta.addr, llid, 0, 0);
 463                         break;
 464                 }
 465                 reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);
 466                 /* fall through on else */
 467         case NL80211_PLINK_CNF_RCVD:
 468                 /* confirm timer */
 469                 if (!reason)
 470                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);
 471                 sta->plink_state = NL80211_PLINK_HOLDING;
 472                 mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 473                 spin_unlock_bh(&sta->lock);
 474                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 475                                     sta->sta.addr, llid, plid, reason);
 476                 break;
 477         case NL80211_PLINK_HOLDING:
 478                 /* holding timer */
 479                 del_timer(&sta->plink_timer);
 480                 mesh_plink_fsm_restart(sta);
 481                 spin_unlock_bh(&sta->lock);
 482                 break;
 483         default:
 484                 spin_unlock_bh(&sta->lock);
 485                 break;
 486         }
 487 }
 488
 489 #ifdef CONFIG_PM
 490 void mesh_plink_quiesce(struct sta_info *sta)
 491 {
 492         if (del_timer_sync(&sta->plink_timer))
 493                 sta->plink_timer_was_running = true;
 494 }
 495
 496 void mesh_plink_restart(struct sta_info *sta)
 497 {
 498         if (sta->plink_timer_was_running) {
 499                 add_timer(&sta->plink_timer);
 500                 sta->plink_timer_was_running = false;
 501         }
 502 }
 503 #endif
 504
 505 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 506 {
 507         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 508         sta->plink_timer.data = (unsigned long) sta;
 509         sta->plink_timer.function = mesh_plink_timer;
 510         sta->plink_timeout = timeout;
 511         add_timer(&sta->plink_timer);
 512 }
 513
 514 int mesh_plink_open(struct sta_info *sta)
 515 {
 516         __le16 llid;
 517         struct ieee80211_sub_if_data *sdata = sta->sdata;
 518
 519         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 520                 return -EPERM;
 521
 522         spin_lock_bh(&sta->lock);
 523         get_random_bytes(&llid, 2);
 524         sta->llid = llid;
 525         if (sta->plink_state != NL80211_PLINK_LISTEN) {
 526                 spin_unlock_bh(&sta->lock);
 527                 return -EBUSY;
 528         }
 529         sta->plink_state = NL80211_PLINK_OPN_SNT;
 530         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 531         spin_unlock_bh(&sta->lock);
 532         mpl_dbg(sdata,
 533                 "Mesh plink: starting establishment with %pM\n",
 534                 sta->sta.addr);
 535
 536         return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 537                                    sta->sta.addr, llid, 0, 0);
 538 }
 539
 540 void mesh_plink_block(struct sta_info *sta)
 541 {
 542         struct ieee80211_sub_if_data *sdata = sta->sdata;
 543         bool deactivated;
 544
 545         spin_lock_bh(&sta->lock);
 546         deactivated = __mesh_plink_deactivate(sta);
 547         sta->plink_state = NL80211_PLINK_BLOCKED;
 548         spin_unlock_bh(&sta->lock);
 549
 550         if (deactivated)
 551                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 552 }
 553
 554
 555 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,
 556                          size_t len, struct ieee80211_rx_status *rx_status)
 557 {
 558         struct ieee802_11_elems elems;
 559         struct sta_info *sta;
 560         enum plink_event event;
 561         enum ieee80211_self_protected_actioncode ftype;
 562         size_t baselen;
 563         bool matches_local = true;
 564         u8 ie_len;
 565         u8 *baseaddr;
 566         u32 changed = 0;
 567         __le16 plid, llid, reason;
 568         static const char *mplstates[] = {
 569                 [NL80211_PLINK_LISTEN] = "LISTEN",
 570                 [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 571                 [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 572                 [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 573                 [NL80211_PLINK_ESTAB] = "ESTAB",
 574                 [NL80211_PLINK_HOLDING] = "HOLDING",
 575                 [NL80211_PLINK_BLOCKED] = "BLOCKED"
 576         };
 577
 578         /* need action_code, aux */
 579         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
 580                 return;
 581
 582         if (is_multicast_ether_addr(mgmt->da)) {
 583                 mpl_dbg(sdata,
 584                         "Mesh plink: ignore frame from multicast address\n");
 585                 return;
 586         }
 587
 588         baseaddr = mgmt->u.action.u.self_prot.variable;
 589         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
 590         if (mgmt->u.action.u.self_prot.action_code ==
 591                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
 592                 baseaddr += 4;
 593                 baselen += 4;
 594         }
 595         ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
 596         if (!elems.peering) {
 597                 mpl_dbg(sdata,
 598                         "Mesh plink: missing necessary peer link ie\n");
 599                 return;
 600         }
 601         if (elems.rsn_len &&
 602                         sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
 603                 mpl_dbg(sdata,
 604                         "Mesh plink: can't establish link with secure peer\n");
 605                 return;
 606         }
 607
 608         ftype = mgmt->u.action.u.self_prot.action_code;
 609         ie_len = elems.peering_len;
 610         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
 611             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
 612             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
 613                                                         && ie_len != 8)) {
 614                 mpl_dbg(sdata,
 615                         "Mesh plink: incorrect plink ie length %d %d\n",
 616                         ftype, ie_len);
 617                 return;
 618         }
 619
 620         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 621                                 (!elems.mesh_id || !elems.mesh_config)) {
 622                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
 623                 return;
 624         }
 625         /* Note the lines below are correct, the llid in the frame is the plid
 626          * from the point of view of this host.
 627          */
 628         memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
 629         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
 630             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
 631                 memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
 632
 633         rcu_read_lock();
 634
 635         sta = sta_info_get(sdata, mgmt->sa);
 636         if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
 637                 mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 638                 rcu_read_unlock();
 639                 return;
 640         }
 641
 642         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
 643             !rssi_threshold_check(sta, sdata)) {
 644                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
 645                         mgmt->sa);
 646                 rcu_read_unlock();
 647                 return;
 648         }
 649
 650         if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
 651                 mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 652                 rcu_read_unlock();
 653                 return;
 654         }
 655
 656         if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
 657                 rcu_read_unlock();
 658                 return;
 659         }
 660
 661         /* Now we will figure out the appropriate event... */
 662         event = PLINK_UNDEFINED;
 663         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 664             !mesh_matches_local(sdata, &elems)) {
 665                 matches_local = false;
 666                 switch (ftype) {
 667                 case WLAN_SP_MESH_PEERING_OPEN:
 668                         event = OPN_RJCT;
 669                         break;
 670                 case WLAN_SP_MESH_PEERING_CONFIRM:
 671                         event = CNF_RJCT;
 672                         break;
 673                 default:
 674                         break;
 675                 }
 676         }
 677
 678         if (!sta && !matches_local) {
 679                 rcu_read_unlock();
 680                 reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 681                 llid = 0;
 682                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 683                                     mgmt->sa, llid, plid, reason);
 684                 return;
 685         } else if (!sta) {
 686                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 687                 if (!mesh_plink_free_count(sdata)) {
 688                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 689                         rcu_read_unlock();
 690                         return;
 691                 }
 692                 event = OPN_ACPT;
 693         } else if (matches_local) {
 694                 switch (ftype) {
 695                 case WLAN_SP_MESH_PEERING_OPEN:
 696                         if (!mesh_plink_free_count(sdata) ||
 697                             (sta->plid && sta->plid != plid))
 698                                 event = OPN_IGNR;
 699                         else
 700                                 event = OPN_ACPT;
 701                         break;
 702                 case WLAN_SP_MESH_PEERING_CONFIRM:
 703                         if (!mesh_plink_free_count(sdata) ||
 704                             (sta->llid != llid || sta->plid != plid))
 705                                 event = CNF_IGNR;
 706                         else
 707                                 event = CNF_ACPT;
 708                         break;
 709                 case WLAN_SP_MESH_PEERING_CLOSE:
 710                         if (sta->plink_state == NL80211_PLINK_ESTAB)
 711                                 /* Do not check for llid or plid. This does not
 712                                  * follow the standard but since multiple plinks
 713                                  * per sta are not supported, it is necessary in
 714                                  * order to avoid a livelock when MP A sees an
 715                                  * establish peer link to MP B but MP B does not
 716                                  * see it. This can be caused by a timeout in
 717                                  * B's peer link establishment or B beign
 718                                  * restarted.
 719                                  */
 720                                 event = CLS_ACPT;
 721                         else if (sta->plid != plid)
 722                                 event = CLS_IGNR;
 723                         else if (ie_len == 7 && sta->llid != llid)
 724                                 event = CLS_IGNR;
 725                         else
 726                                 event = CLS_ACPT;
 727                         break;
 728                 default:
 729                         mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 730                         rcu_read_unlock();
 731                         return;
 732                 }
 733         }
 734
 735         if (event == OPN_ACPT) {
 736                 /* allocate sta entry if necessary and update info */
 737                 sta = mesh_peer_init(sdata, mgmt->sa, &elems);
 738                 if (!sta) {
 739                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
 740                         rcu_read_unlock();
 741                         return;
 742                 }
 743         }
 744
 745         mpl_dbg(sdata,
 746                 "Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
 747                 mgmt->sa, mplstates[sta->plink_state],
 748                 le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
 749                 event);
 750         reason = 0;
 751         spin_lock_bh(&sta->lock);
 752         switch (sta->plink_state) {
 753                 /* spin_unlock as soon as state is updated at each case */
 754         case NL80211_PLINK_LISTEN:
 755                 switch (event) {
 756                 case CLS_ACPT:
 757                         mesh_plink_fsm_restart(sta);
 758                         spin_unlock_bh(&sta->lock);
 759                         break;
 760                 case OPN_ACPT:
 761                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 762                         sta->plid = plid;
 763                         get_random_bytes(&llid, 2);
 764                         sta->llid = llid;
 765                         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 766                         spin_unlock_bh(&sta->lock);
 767                         mesh_plink_frame_tx(sdata,
 768                                             WLAN_SP_MESH_PEERING_OPEN,
 769                                             sta->sta.addr, llid, 0, 0);
 770                         mesh_plink_frame_tx(sdata,
 771                                             WLAN_SP_MESH_PEERING_CONFIRM,
 772                                             sta->sta.addr, llid, plid, 0);
 773                         break;
 774                 default:
 775                         spin_unlock_bh(&sta->lock);
 776                         break;
 777                 }
 778                 break;
 779
 780         case NL80211_PLINK_OPN_SNT:
 781                 switch (event) {
 782                 case OPN_RJCT:
 783                 case CNF_RJCT:
 784                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 785                 case CLS_ACPT:
 786                         if (!reason)
 787                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 788                         sta->reason = reason;
 789                         sta->plink_state = NL80211_PLINK_HOLDING;
 790                         if (!mod_plink_timer(sta,
 791                                              dot11MeshHoldingTimeout(sdata)))
 792                                 sta->ignore_plink_timer = true;
 793
 794                         llid = sta->llid;
 795                         spin_unlock_bh(&sta->lock);
 796                         mesh_plink_frame_tx(sdata,
 797                                             WLAN_SP_MESH_PEERING_CLOSE,
 798                                             sta->sta.addr, llid, plid, reason);
 799                         break;
 800                 case OPN_ACPT:
 801                         /* retry timer is left untouched */
 802                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 803                         sta->plid = plid;
 804                         llid = sta->llid;
 805                         spin_unlock_bh(&sta->lock);
 806                         mesh_plink_frame_tx(sdata,
 807                                             WLAN_SP_MESH_PEERING_CONFIRM,
 808                                             sta->sta.addr, llid, plid, 0);
 809                         break;
 810                 case CNF_ACPT:
 811                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 812                         if (!mod_plink_timer(sta,
 813                                              dot11MeshConfirmTimeout(sdata)))
 814                                 sta->ignore_plink_timer = true;
 815
 816                         spin_unlock_bh(&sta->lock);
 817                         break;
 818                 default:
 819                         spin_unlock_bh(&sta->lock);
 820                         break;
 821                 }
 822                 break;
 823
 824         case NL80211_PLINK_OPN_RCVD:
 825                 switch (event) {
 826                 case OPN_RJCT:
 827                 case CNF_RJCT:
 828                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 829                 case CLS_ACPT:
 830                         if (!reason)
 831                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 832                         sta->reason = reason;
 833                         sta->plink_state = NL80211_PLINK_HOLDING;
 834                         if (!mod_plink_timer(sta,
 835                                              dot11MeshHoldingTimeout(sdata)))
 836                                 sta->ignore_plink_timer = true;
 837
 838                         llid = sta->llid;
 839                         spin_unlock_bh(&sta->lock);
 840                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 841                                             sta->sta.addr, llid, plid, reason);
 842                         break;
 843                 case OPN_ACPT:
 844                         llid = sta->llid;
 845                         spin_unlock_bh(&sta->lock);
 846                         mesh_plink_frame_tx(sdata,
 847                                             WLAN_SP_MESH_PEERING_CONFIRM,
 848                                             sta->sta.addr, llid, plid, 0);
 849                         break;
 850                 case CNF_ACPT:
 851                         del_timer(&sta->plink_timer);
 852                         sta->plink_state = NL80211_PLINK_ESTAB;
 853                         spin_unlock_bh(&sta->lock);
 854                         mesh_plink_inc_estab_count(sdata);
 855                         changed |= mesh_set_ht_prot_mode(sdata);
 856                         changed |= BSS_CHANGED_BEACON;
 857                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 858                                 sta->sta.addr);
 859                         break;
 860                 default:
 861                         spin_unlock_bh(&sta->lock);
 862                         break;
 863                 }
 864                 break;
 865
 866         case NL80211_PLINK_CNF_RCVD:
 867                 switch (event) {
 868                 case OPN_RJCT:
 869                 case CNF_RJCT:
 870                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 871                 case CLS_ACPT:
 872                         if (!reason)
 873                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 874                         sta->reason = reason;
 875                         sta->plink_state = NL80211_PLINK_HOLDING;
 876                         if (!mod_plink_timer(sta,
 877                                              dot11MeshHoldingTimeout(sdata)))
 878                                 sta->ignore_plink_timer = true;
 879
 880                         llid = sta->llid;
 881                         spin_unlock_bh(&sta->lock);
 882                         mesh_plink_frame_tx(sdata,
 883                                             WLAN_SP_MESH_PEERING_CLOSE,
 884                                             sta->sta.addr, llid, plid, reason);
 885                         break;
 886                 case OPN_ACPT:
 887                         del_timer(&sta->plink_timer);
 888                         sta->plink_state = NL80211_PLINK_ESTAB;
 889                         spin_unlock_bh(&sta->lock);
 890                         mesh_plink_inc_estab_count(sdata);
 891                         changed |= mesh_set_ht_prot_mode(sdata);
 892                         changed |= BSS_CHANGED_BEACON;
 893                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 894                                 sta->sta.addr);
 895                         mesh_plink_frame_tx(sdata,
 896                                             WLAN_SP_MESH_PEERING_CONFIRM,
 897                                             sta->sta.addr, llid, plid, 0);
 898                         break;
 899                 default:
 900                         spin_unlock_bh(&sta->lock);
 901                         break;
 902                 }
 903                 break;
 904
 905         case NL80211_PLINK_ESTAB:
 906                 switch (event) {
 907                 case CLS_ACPT:
 908                         reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 909                         sta->reason = reason;
 910                         __mesh_plink_deactivate(sta);
 911                         sta->plink_state = NL80211_PLINK_HOLDING;
 912                         llid = sta->llid;
 913                         mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 914                         spin_unlock_bh(&sta->lock);
 915                         changed |= mesh_set_ht_prot_mode(sdata);
 916                         changed |= BSS_CHANGED_BEACON;
 917                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 918                                             sta->sta.addr, llid, plid, reason);
 919                         break;
 920                 case OPN_ACPT:
 921                         llid = sta->llid;
 922                         spin_unlock_bh(&sta->lock);
 923                         mesh_plink_frame_tx(sdata,
 924                                             WLAN_SP_MESH_PEERING_CONFIRM,
 925                                             sta->sta.addr, llid, plid, 0);
 926                         break;
 927                 default:
 928                         spin_unlock_bh(&sta->lock);
 929                         break;
 930                 }
 931                 break;
 932         case NL80211_PLINK_HOLDING:
 933                 switch (event) {
 934                 case CLS_ACPT:
 935                         if (del_timer(&sta->plink_timer))
 936                                 sta->ignore_plink_timer = 1;
 937                         mesh_plink_fsm_restart(sta);
 938                         spin_unlock_bh(&sta->lock);
 939                         break;
 940                 case OPN_ACPT:
 941                 case CNF_ACPT:
 942                 case OPN_RJCT:
 943                 case CNF_RJCT:
 944                         llid = sta->llid;
 945                         reason = sta->reason;
 946                         spin_unlock_bh(&sta->lock);
 947                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 948                                             sta->sta.addr, llid, plid, reason);
 949                         break;
 950                 default:
 951                         spin_unlock_bh(&sta->lock);
 952                 }
 953                 break;
 954         default:
 955                 /* should not get here, PLINK_BLOCKED is dealt with at the
 956                  * beginning of the function
 957                  */
 958                 spin_unlock_bh(&sta->lock);
 959                 break;
 960         }
 961
 962         rcu_read_unlock();
 963
 964         if (changed)
 965                 ieee80211_bss_info_change_notify(sdata, changed);
 966 }