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 /**
 324  * mesh_peer_init - initialize new mesh peer and return resulting sta_info
 325  *
 326  * @sdata: local meshif
 327  * @addr: peer's address
 328  * @elems: IEs from beacon or mesh peering frame
 329  *
 330  * call under RCU
 331  */
 332 static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata,
 333                                        u8 *addr,
 334                                        struct ieee802_11_elems *elems)
 335 {
 336         struct ieee80211_local *local = sdata->local;
 337         enum ieee80211_band band = local->oper_channel->band;
 338         struct ieee80211_supported_band *sband;
 339         u32 rates, basic_rates = 0;
 340         struct sta_info *sta;
 341         bool insert = false;
 342
 343         sband = local->hw.wiphy->bands[band];
 344         rates = ieee80211_sta_get_rates(local, elems, band, &basic_rates);
 345
 346         sta = sta_info_get(sdata, addr);
 347         if (!sta) {
 348                 /* Userspace handles peer allocation when security is enabled */
 349                 if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
 350                         cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 351                                                            elems->ie_start,
 352                                                            elems->total_len,
 353                                                            GFP_ATOMIC);
 354                         return NULL;
 355                 }
 356
 357                 sta = mesh_plink_alloc(sdata, addr);
 358                 if (!sta)
 359                         return NULL;
 360                 insert = true;
 361         }
 362
 363         spin_lock_bh(&sta->lock);
 364         sta->last_rx = jiffies;
 365         sta->sta.supp_rates[band] = rates;
 366         if (elems->ht_cap_elem &&
 367             sdata->local->_oper_channel_type != NL80211_CHAN_NO_HT)
 368                 ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 369                                                   elems->ht_cap_elem,
 370                                                   &sta->sta.ht_cap);
 371         else
 372                 memset(&sta->sta.ht_cap, 0, sizeof(sta->sta.ht_cap));
 373
 374         if (elems->ht_operation) {
 375                 if (!(elems->ht_operation->ht_param &
 376                       IEEE80211_HT_PARAM_CHAN_WIDTH_ANY))
 377                         sta->sta.ht_cap.cap &=
 378                                             ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 379                 sta->ch_type =
 380                         ieee80211_ht_oper_to_channel_type(elems->ht_operation);
 381         }
 382
 383         rate_control_rate_init(sta);
 384         spin_unlock_bh(&sta->lock);
 385
 386         if (insert && sta_info_insert(sta))
 387                 return NULL;
 388
 389         return sta;
 390 }
 391
 392 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 393                            u8 *hw_addr,
 394                            struct ieee802_11_elems *elems)
 395 {
 396         struct sta_info *sta;
 397
 398         rcu_read_lock();
 399         sta = mesh_peer_init(sdata, hw_addr, elems);
 400         if (!sta)
 401                 goto out;
 402
 403         if (mesh_peer_accepts_plinks(elems) &&
 404             sta->plink_state == NL80211_PLINK_LISTEN &&
 405             sdata->u.mesh.accepting_plinks &&
 406             sdata->u.mesh.mshcfg.auto_open_plinks &&
 407             rssi_threshold_check(sta, sdata))
 408                 mesh_plink_open(sta);
 409
 410 out:
 411         rcu_read_unlock();
 412 }
 413
 414 static void mesh_plink_timer(unsigned long data)
 415 {
 416         struct sta_info *sta;
 417         __le16 llid, plid, reason;
 418         struct ieee80211_sub_if_data *sdata;
 419
 420         /*
 421          * This STA is valid because sta_info_destroy() will
 422          * del_timer_sync() this timer after having made sure
 423          * it cannot be readded (by deleting the plink.)
 424          */
 425         sta = (struct sta_info *) data;
 426
 427         if (sta->sdata->local->quiescing) {
 428                 sta->plink_timer_was_running = true;
 429                 return;
 430         }
 431
 432         spin_lock_bh(&sta->lock);
 433         if (sta->ignore_plink_timer) {
 434                 sta->ignore_plink_timer = false;
 435                 spin_unlock_bh(&sta->lock);
 436                 return;
 437         }
 438         mpl_dbg(sta->sdata,
 439                 "Mesh plink timer for %pM fired on state %d\n",
 440                 sta->sta.addr, sta->plink_state);
 441         reason = 0;
 442         llid = sta->llid;
 443         plid = sta->plid;
 444         sdata = sta->sdata;
 445
 446         switch (sta->plink_state) {
 447         case NL80211_PLINK_OPN_RCVD:
 448         case NL80211_PLINK_OPN_SNT:
 449                 /* retry timer */
 450                 if (sta->plink_retries < dot11MeshMaxRetries(sdata)) {
 451                         u32 rand;
 452                         mpl_dbg(sta->sdata,
 453                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 454                                 sta->sta.addr, sta->plink_retries,
 455                                 sta->plink_timeout);
 456                         get_random_bytes(&rand, sizeof(u32));
 457                         sta->plink_timeout = sta->plink_timeout +
 458                                              rand % sta->plink_timeout;
 459                         ++sta->plink_retries;
 460                         mod_plink_timer(sta, sta->plink_timeout);
 461                         spin_unlock_bh(&sta->lock);
 462                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 463                                             sta->sta.addr, llid, 0, 0);
 464                         break;
 465                 }
 466                 reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);
 467                 /* fall through on else */
 468         case NL80211_PLINK_CNF_RCVD:
 469                 /* confirm timer */
 470                 if (!reason)
 471                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);
 472                 sta->plink_state = NL80211_PLINK_HOLDING;
 473                 mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 474                 spin_unlock_bh(&sta->lock);
 475                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 476                                     sta->sta.addr, llid, plid, reason);
 477                 break;
 478         case NL80211_PLINK_HOLDING:
 479                 /* holding timer */
 480                 del_timer(&sta->plink_timer);
 481                 mesh_plink_fsm_restart(sta);
 482                 spin_unlock_bh(&sta->lock);
 483                 break;
 484         default:
 485                 spin_unlock_bh(&sta->lock);
 486                 break;
 487         }
 488 }
 489
 490 #ifdef CONFIG_PM
 491 void mesh_plink_quiesce(struct sta_info *sta)
 492 {
 493         if (del_timer_sync(&sta->plink_timer))
 494                 sta->plink_timer_was_running = true;
 495 }
 496
 497 void mesh_plink_restart(struct sta_info *sta)
 498 {
 499         if (sta->plink_timer_was_running) {
 500                 add_timer(&sta->plink_timer);
 501                 sta->plink_timer_was_running = false;
 502         }
 503 }
 504 #endif
 505
 506 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 507 {
 508         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 509         sta->plink_timer.data = (unsigned long) sta;
 510         sta->plink_timer.function = mesh_plink_timer;
 511         sta->plink_timeout = timeout;
 512         add_timer(&sta->plink_timer);
 513 }
 514
 515 int mesh_plink_open(struct sta_info *sta)
 516 {
 517         __le16 llid;
 518         struct ieee80211_sub_if_data *sdata = sta->sdata;
 519
 520         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 521                 return -EPERM;
 522
 523         spin_lock_bh(&sta->lock);
 524         get_random_bytes(&llid, 2);
 525         sta->llid = llid;
 526         if (sta->plink_state != NL80211_PLINK_LISTEN) {
 527                 spin_unlock_bh(&sta->lock);
 528                 return -EBUSY;
 529         }
 530         sta->plink_state = NL80211_PLINK_OPN_SNT;
 531         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 532         spin_unlock_bh(&sta->lock);
 533         mpl_dbg(sdata,
 534                 "Mesh plink: starting establishment with %pM\n",
 535                 sta->sta.addr);
 536
 537         return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 538                                    sta->sta.addr, llid, 0, 0);
 539 }
 540
 541 void mesh_plink_block(struct sta_info *sta)
 542 {
 543         struct ieee80211_sub_if_data *sdata = sta->sdata;
 544         bool deactivated;
 545
 546         spin_lock_bh(&sta->lock);
 547         deactivated = __mesh_plink_deactivate(sta);
 548         sta->plink_state = NL80211_PLINK_BLOCKED;
 549         spin_unlock_bh(&sta->lock);
 550
 551         if (deactivated)
 552                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 553 }
 554
 555
 556 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,
 557                          size_t len, struct ieee80211_rx_status *rx_status)
 558 {
 559         struct ieee802_11_elems elems;
 560         struct sta_info *sta;
 561         enum plink_event event;
 562         enum ieee80211_self_protected_actioncode ftype;
 563         size_t baselen;
 564         bool matches_local = true;
 565         u8 ie_len;
 566         u8 *baseaddr;
 567         u32 changed = 0;
 568         __le16 plid, llid, reason;
 569         static const char *mplstates[] = {
 570                 [NL80211_PLINK_LISTEN] = "LISTEN",
 571                 [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 572                 [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 573                 [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 574                 [NL80211_PLINK_ESTAB] = "ESTAB",
 575                 [NL80211_PLINK_HOLDING] = "HOLDING",
 576                 [NL80211_PLINK_BLOCKED] = "BLOCKED"
 577         };
 578
 579         /* need action_code, aux */
 580         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
 581                 return;
 582
 583         if (is_multicast_ether_addr(mgmt->da)) {
 584                 mpl_dbg(sdata,
 585                         "Mesh plink: ignore frame from multicast address\n");
 586                 return;
 587         }
 588
 589         baseaddr = mgmt->u.action.u.self_prot.variable;
 590         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
 591         if (mgmt->u.action.u.self_prot.action_code ==
 592                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
 593                 baseaddr += 4;
 594                 baselen += 4;
 595         }
 596         ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
 597         if (!elems.peering) {
 598                 mpl_dbg(sdata,
 599                         "Mesh plink: missing necessary peer link ie\n");
 600                 return;
 601         }
 602         if (elems.rsn_len &&
 603                         sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
 604                 mpl_dbg(sdata,
 605                         "Mesh plink: can't establish link with secure peer\n");
 606                 return;
 607         }
 608
 609         ftype = mgmt->u.action.u.self_prot.action_code;
 610         ie_len = elems.peering_len;
 611         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
 612             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
 613             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
 614                                                         && ie_len != 8)) {
 615                 mpl_dbg(sdata,
 616                         "Mesh plink: incorrect plink ie length %d %d\n",
 617                         ftype, ie_len);
 618                 return;
 619         }
 620
 621         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 622                                 (!elems.mesh_id || !elems.mesh_config)) {
 623                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
 624                 return;
 625         }
 626         /* Note the lines below are correct, the llid in the frame is the plid
 627          * from the point of view of this host.
 628          */
 629         memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
 630         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
 631             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
 632                 memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
 633
 634         rcu_read_lock();
 635
 636         sta = sta_info_get(sdata, mgmt->sa);
 637         if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
 638                 mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 639                 rcu_read_unlock();
 640                 return;
 641         }
 642
 643         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
 644             !rssi_threshold_check(sta, sdata)) {
 645                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
 646                         mgmt->sa);
 647                 rcu_read_unlock();
 648                 return;
 649         }
 650
 651         if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
 652                 mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 653                 rcu_read_unlock();
 654                 return;
 655         }
 656
 657         if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
 658                 rcu_read_unlock();
 659                 return;
 660         }
 661
 662         /* Now we will figure out the appropriate event... */
 663         event = PLINK_UNDEFINED;
 664         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 665             !mesh_matches_local(sdata, &elems)) {
 666                 matches_local = false;
 667                 switch (ftype) {
 668                 case WLAN_SP_MESH_PEERING_OPEN:
 669                         event = OPN_RJCT;
 670                         break;
 671                 case WLAN_SP_MESH_PEERING_CONFIRM:
 672                         event = CNF_RJCT;
 673                         break;
 674                 default:
 675                         break;
 676                 }
 677         }
 678
 679         if (!sta && !matches_local) {
 680                 rcu_read_unlock();
 681                 reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 682                 llid = 0;
 683                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 684                                     mgmt->sa, llid, plid, reason);
 685                 return;
 686         } else if (!sta) {
 687                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 688                 if (!mesh_plink_free_count(sdata)) {
 689                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 690                         rcu_read_unlock();
 691                         return;
 692                 }
 693                 event = OPN_ACPT;
 694         } else if (matches_local) {
 695                 switch (ftype) {
 696                 case WLAN_SP_MESH_PEERING_OPEN:
 697                         if (!mesh_plink_free_count(sdata) ||
 698                             (sta->plid && sta->plid != plid))
 699                                 event = OPN_IGNR;
 700                         else
 701                                 event = OPN_ACPT;
 702                         break;
 703                 case WLAN_SP_MESH_PEERING_CONFIRM:
 704                         if (!mesh_plink_free_count(sdata) ||
 705                             (sta->llid != llid || sta->plid != plid))
 706                                 event = CNF_IGNR;
 707                         else
 708                                 event = CNF_ACPT;
 709                         break;
 710                 case WLAN_SP_MESH_PEERING_CLOSE:
 711                         if (sta->plink_state == NL80211_PLINK_ESTAB)
 712                                 /* Do not check for llid or plid. This does not
 713                                  * follow the standard but since multiple plinks
 714                                  * per sta are not supported, it is necessary in
 715                                  * order to avoid a livelock when MP A sees an
 716                                  * establish peer link to MP B but MP B does not
 717                                  * see it. This can be caused by a timeout in
 718                                  * B's peer link establishment or B beign
 719                                  * restarted.
 720                                  */
 721                                 event = CLS_ACPT;
 722                         else if (sta->plid != plid)
 723                                 event = CLS_IGNR;
 724                         else if (ie_len == 7 && sta->llid != llid)
 725                                 event = CLS_IGNR;
 726                         else
 727                                 event = CLS_ACPT;
 728                         break;
 729                 default:
 730                         mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 731                         rcu_read_unlock();
 732                         return;
 733                 }
 734         }
 735
 736         if (event == OPN_ACPT) {
 737                 /* allocate sta entry if necessary and update info */
 738                 sta = mesh_peer_init(sdata, mgmt->sa, &elems);
 739                 if (!sta) {
 740                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
 741                         rcu_read_unlock();
 742                         return;
 743                 }
 744         }
 745
 746         mpl_dbg(sdata,
 747                 "Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
 748                 mgmt->sa, mplstates[sta->plink_state],
 749                 le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
 750                 event);
 751         reason = 0;
 752         spin_lock_bh(&sta->lock);
 753         switch (sta->plink_state) {
 754                 /* spin_unlock as soon as state is updated at each case */
 755         case NL80211_PLINK_LISTEN:
 756                 switch (event) {
 757                 case CLS_ACPT:
 758                         mesh_plink_fsm_restart(sta);
 759                         spin_unlock_bh(&sta->lock);
 760                         break;
 761                 case OPN_ACPT:
 762                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 763                         sta->plid = plid;
 764                         get_random_bytes(&llid, 2);
 765                         sta->llid = llid;
 766                         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 767                         spin_unlock_bh(&sta->lock);
 768                         mesh_plink_frame_tx(sdata,
 769                                             WLAN_SP_MESH_PEERING_OPEN,
 770                                             sta->sta.addr, llid, 0, 0);
 771                         mesh_plink_frame_tx(sdata,
 772                                             WLAN_SP_MESH_PEERING_CONFIRM,
 773                                             sta->sta.addr, llid, plid, 0);
 774                         break;
 775                 default:
 776                         spin_unlock_bh(&sta->lock);
 777                         break;
 778                 }
 779                 break;
 780
 781         case NL80211_PLINK_OPN_SNT:
 782                 switch (event) {
 783                 case OPN_RJCT:
 784                 case CNF_RJCT:
 785                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 786                 case CLS_ACPT:
 787                         if (!reason)
 788                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 789                         sta->reason = reason;
 790                         sta->plink_state = NL80211_PLINK_HOLDING;
 791                         if (!mod_plink_timer(sta,
 792                                              dot11MeshHoldingTimeout(sdata)))
 793                                 sta->ignore_plink_timer = true;
 794
 795                         llid = sta->llid;
 796                         spin_unlock_bh(&sta->lock);
 797                         mesh_plink_frame_tx(sdata,
 798                                             WLAN_SP_MESH_PEERING_CLOSE,
 799                                             sta->sta.addr, llid, plid, reason);
 800                         break;
 801                 case OPN_ACPT:
 802                         /* retry timer is left untouched */
 803                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 804                         sta->plid = plid;
 805                         llid = sta->llid;
 806                         spin_unlock_bh(&sta->lock);
 807                         mesh_plink_frame_tx(sdata,
 808                                             WLAN_SP_MESH_PEERING_CONFIRM,
 809                                             sta->sta.addr, llid, plid, 0);
 810                         break;
 811                 case CNF_ACPT:
 812                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 813                         if (!mod_plink_timer(sta,
 814                                              dot11MeshConfirmTimeout(sdata)))
 815                                 sta->ignore_plink_timer = true;
 816
 817                         spin_unlock_bh(&sta->lock);
 818                         break;
 819                 default:
 820                         spin_unlock_bh(&sta->lock);
 821                         break;
 822                 }
 823                 break;
 824
 825         case NL80211_PLINK_OPN_RCVD:
 826                 switch (event) {
 827                 case OPN_RJCT:
 828                 case CNF_RJCT:
 829                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 830                 case CLS_ACPT:
 831                         if (!reason)
 832                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 833                         sta->reason = reason;
 834                         sta->plink_state = NL80211_PLINK_HOLDING;
 835                         if (!mod_plink_timer(sta,
 836                                              dot11MeshHoldingTimeout(sdata)))
 837                                 sta->ignore_plink_timer = true;
 838
 839                         llid = sta->llid;
 840                         spin_unlock_bh(&sta->lock);
 841                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 842                                             sta->sta.addr, llid, plid, reason);
 843                         break;
 844                 case OPN_ACPT:
 845                         llid = sta->llid;
 846                         spin_unlock_bh(&sta->lock);
 847                         mesh_plink_frame_tx(sdata,
 848                                             WLAN_SP_MESH_PEERING_CONFIRM,
 849                                             sta->sta.addr, llid, plid, 0);
 850                         break;
 851                 case CNF_ACPT:
 852                         del_timer(&sta->plink_timer);
 853                         sta->plink_state = NL80211_PLINK_ESTAB;
 854                         spin_unlock_bh(&sta->lock);
 855                         mesh_plink_inc_estab_count(sdata);
 856                         changed |= mesh_set_ht_prot_mode(sdata);
 857                         changed |= BSS_CHANGED_BEACON;
 858                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 859                                 sta->sta.addr);
 860                         break;
 861                 default:
 862                         spin_unlock_bh(&sta->lock);
 863                         break;
 864                 }
 865                 break;
 866
 867         case NL80211_PLINK_CNF_RCVD:
 868                 switch (event) {
 869                 case OPN_RJCT:
 870                 case CNF_RJCT:
 871                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 872                 case CLS_ACPT:
 873                         if (!reason)
 874                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 875                         sta->reason = reason;
 876                         sta->plink_state = NL80211_PLINK_HOLDING;
 877                         if (!mod_plink_timer(sta,
 878                                              dot11MeshHoldingTimeout(sdata)))
 879                                 sta->ignore_plink_timer = true;
 880
 881                         llid = sta->llid;
 882                         spin_unlock_bh(&sta->lock);
 883                         mesh_plink_frame_tx(sdata,
 884                                             WLAN_SP_MESH_PEERING_CLOSE,
 885                                             sta->sta.addr, llid, plid, reason);
 886                         break;
 887                 case OPN_ACPT:
 888                         del_timer(&sta->plink_timer);
 889                         sta->plink_state = NL80211_PLINK_ESTAB;
 890                         spin_unlock_bh(&sta->lock);
 891                         mesh_plink_inc_estab_count(sdata);
 892                         changed |= mesh_set_ht_prot_mode(sdata);
 893                         changed |= BSS_CHANGED_BEACON;
 894                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 895                                 sta->sta.addr);
 896                         mesh_plink_frame_tx(sdata,
 897                                             WLAN_SP_MESH_PEERING_CONFIRM,
 898                                             sta->sta.addr, llid, plid, 0);
 899                         break;
 900                 default:
 901                         spin_unlock_bh(&sta->lock);
 902                         break;
 903                 }
 904                 break;
 905
 906         case NL80211_PLINK_ESTAB:
 907                 switch (event) {
 908                 case CLS_ACPT:
 909                         reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 910                         sta->reason = reason;
 911                         __mesh_plink_deactivate(sta);
 912                         sta->plink_state = NL80211_PLINK_HOLDING;
 913                         llid = sta->llid;
 914                         mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 915                         spin_unlock_bh(&sta->lock);
 916                         changed |= mesh_set_ht_prot_mode(sdata);
 917                         changed |= BSS_CHANGED_BEACON;
 918                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 919                                             sta->sta.addr, llid, plid, reason);
 920                         break;
 921                 case OPN_ACPT:
 922                         llid = sta->llid;
 923                         spin_unlock_bh(&sta->lock);
 924                         mesh_plink_frame_tx(sdata,
 925                                             WLAN_SP_MESH_PEERING_CONFIRM,
 926                                             sta->sta.addr, llid, plid, 0);
 927                         break;
 928                 default:
 929                         spin_unlock_bh(&sta->lock);
 930                         break;
 931                 }
 932                 break;
 933         case NL80211_PLINK_HOLDING:
 934                 switch (event) {
 935                 case CLS_ACPT:
 936                         if (del_timer(&sta->plink_timer))
 937                                 sta->ignore_plink_timer = 1;
 938                         mesh_plink_fsm_restart(sta);
 939                         spin_unlock_bh(&sta->lock);
 940                         break;
 941                 case OPN_ACPT:
 942                 case CNF_ACPT:
 943                 case OPN_RJCT:
 944                 case CNF_RJCT:
 945                         llid = sta->llid;
 946                         reason = sta->reason;
 947                         spin_unlock_bh(&sta->lock);
 948                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 949                                             sta->sta.addr, llid, plid, reason);
 950                         break;
 951                 default:
 952                         spin_unlock_bh(&sta->lock);
 953                 }
 954                 break;
 955         default:
 956                 /* should not get here, PLINK_BLOCKED is dealt with at the
 957                  * beginning of the function
 958                  */
 959                 spin_unlock_bh(&sta->lock);
 960                 break;
 961         }
 962
 963         rcu_read_unlock();
 964
 965         if (changed)
 966                 ieee80211_bss_info_change_notify(sdata, changed);
 967 }