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_tx_info *info;
 221         struct ieee80211_mgmt *mgmt;
 222         bool include_plid = false;
 223         u16 peering_proto = 0;
 224         u8 *pos, ie_len = 4;
 225         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 226                       sizeof(mgmt->u.action.u.self_prot);
 227         int err = -ENOMEM;
 228
 229         skb = dev_alloc_skb(local->tx_headroom +
 230                             hdr_len +
 231                             2 + /* capability info */
 232                             2 + /* AID */
 233                             2 + 8 + /* supported rates */
 234                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 235                             2 + sdata->u.mesh.mesh_id_len +
 236                             2 + sizeof(struct ieee80211_meshconf_ie) +
 237                             2 + sizeof(struct ieee80211_ht_cap) +
 238                             2 + sizeof(struct ieee80211_ht_operation) +
 239                             2 + 8 + /* peering IE */
 240                             sdata->u.mesh.ie_len);
 241         if (!skb)
 242                 return -1;
 243         info = IEEE80211_SKB_CB(skb);
 244         skb_reserve(skb, local->tx_headroom);
 245         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 246         memset(mgmt, 0, hdr_len);
 247         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 248                                           IEEE80211_STYPE_ACTION);
 249         memcpy(mgmt->da, da, ETH_ALEN);
 250         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 251         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 252         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 253         mgmt->u.action.u.self_prot.action_code = action;
 254
 255         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 256                 /* capability info */
 257                 pos = skb_put(skb, 2);
 258                 memset(pos, 0, 2);
 259                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 260                         /* AID */
 261                         pos = skb_put(skb, 2);
 262                         memcpy(pos + 2, &plid, 2);
 263                 }
 264                 if (ieee80211_add_srates_ie(sdata, skb, true,
 265                                             local->oper_channel->band) ||
 266                     ieee80211_add_ext_srates_ie(sdata, skb, true,
 267                                                 local->oper_channel->band) ||
 268                     mesh_add_rsn_ie(skb, sdata) ||
 269                     mesh_add_meshid_ie(skb, sdata) ||
 270                     mesh_add_meshconf_ie(skb, sdata))
 271                         goto free;
 272         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 273                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
 274                 if (mesh_add_meshid_ie(skb, sdata))
 275                         goto free;
 276         }
 277
 278         /* Add Mesh Peering Management element */
 279         switch (action) {
 280         case WLAN_SP_MESH_PEERING_OPEN:
 281                 break;
 282         case WLAN_SP_MESH_PEERING_CONFIRM:
 283                 ie_len += 2;
 284                 include_plid = true;
 285                 break;
 286         case WLAN_SP_MESH_PEERING_CLOSE:
 287                 if (plid) {
 288                         ie_len += 2;
 289                         include_plid = true;
 290                 }
 291                 ie_len += 2;    /* reason code */
 292                 break;
 293         default:
 294                 err = -EINVAL;
 295                 goto free;
 296         }
 297
 298         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 299                 goto free;
 300
 301         pos = skb_put(skb, 2 + ie_len);
 302         *pos++ = WLAN_EID_PEER_MGMT;
 303         *pos++ = ie_len;
 304         memcpy(pos, &peering_proto, 2);
 305         pos += 2;
 306         memcpy(pos, &llid, 2);
 307         pos += 2;
 308         if (include_plid) {
 309                 memcpy(pos, &plid, 2);
 310                 pos += 2;
 311         }
 312         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 313                 memcpy(pos, &reason, 2);
 314                 pos += 2;
 315         }
 316
 317         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 318                 if (mesh_add_ht_cap_ie(skb, sdata) ||
 319                     mesh_add_ht_oper_ie(skb, sdata))
 320                         goto free;
 321         }
 322
 323         if (mesh_add_vendor_ies(skb, sdata))
 324                 goto free;
 325
 326         ieee80211_tx_skb(sdata, skb);
 327         return 0;
 328 free:
 329         kfree_skb(skb);
 330         return err;
 331 }
 332
 333 /**
 334  * mesh_peer_init - initialize new mesh peer and return resulting sta_info
 335  *
 336  * @sdata: local meshif
 337  * @addr: peer's address
 338  * @elems: IEs from beacon or mesh peering frame
 339  *
 340  * call under RCU
 341  */
 342 static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata,
 343                                        u8 *addr,
 344                                        struct ieee802_11_elems *elems)
 345 {
 346         struct ieee80211_local *local = sdata->local;
 347         enum ieee80211_band band = local->oper_channel->band;
 348         struct ieee80211_supported_band *sband;
 349         u32 rates, basic_rates = 0;
 350         struct sta_info *sta;
 351         bool insert = false;
 352
 353         sband = local->hw.wiphy->bands[band];
 354         rates = ieee80211_sta_get_rates(local, elems, band, &basic_rates);
 355
 356         sta = sta_info_get(sdata, addr);
 357         if (!sta) {
 358                 /* Userspace handles peer allocation when security is enabled */
 359                 if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
 360                         cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 361                                                            elems->ie_start,
 362                                                            elems->total_len,
 363                                                            GFP_ATOMIC);
 364                         return NULL;
 365                 }
 366
 367                 sta = mesh_plink_alloc(sdata, addr);
 368                 if (!sta)
 369                         return NULL;
 370                 insert = true;
 371         }
 372
 373         spin_lock_bh(&sta->lock);
 374         sta->last_rx = jiffies;
 375         if (sta->plink_state == NL80211_PLINK_ESTAB) {
 376                 spin_unlock_bh(&sta->lock);
 377                 return sta;
 378         }
 379
 380         sta->sta.supp_rates[band] = rates;
 381         if (elems->ht_cap_elem &&
 382             sdata->local->_oper_channel_type != NL80211_CHAN_NO_HT)
 383                 ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 384                                                   elems->ht_cap_elem,
 385                                                   &sta->sta.ht_cap);
 386         else
 387                 memset(&sta->sta.ht_cap, 0, sizeof(sta->sta.ht_cap));
 388
 389         if (elems->ht_operation) {
 390                 if (!(elems->ht_operation->ht_param &
 391                       IEEE80211_HT_PARAM_CHAN_WIDTH_ANY))
 392                         sta->sta.ht_cap.cap &=
 393                                             ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 394                 sta->ch_type =
 395                         ieee80211_ht_oper_to_channel_type(elems->ht_operation);
 396         }
 397
 398         rate_control_rate_init(sta);
 399         spin_unlock_bh(&sta->lock);
 400
 401         if (insert && sta_info_insert(sta))
 402                 return NULL;
 403
 404         return sta;
 405 }
 406
 407 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 408                            u8 *hw_addr,
 409                            struct ieee802_11_elems *elems)
 410 {
 411         struct sta_info *sta;
 412
 413         rcu_read_lock();
 414         sta = mesh_peer_init(sdata, hw_addr, elems);
 415         if (!sta)
 416                 goto out;
 417
 418         if (mesh_peer_accepts_plinks(elems) &&
 419             sta->plink_state == NL80211_PLINK_LISTEN &&
 420             sdata->u.mesh.accepting_plinks &&
 421             sdata->u.mesh.mshcfg.auto_open_plinks &&
 422             rssi_threshold_check(sta, sdata))
 423                 mesh_plink_open(sta);
 424
 425 out:
 426         rcu_read_unlock();
 427 }
 428
 429 static void mesh_plink_timer(unsigned long data)
 430 {
 431         struct sta_info *sta;
 432         __le16 llid, plid, reason;
 433         struct ieee80211_sub_if_data *sdata;
 434
 435         /*
 436          * This STA is valid because sta_info_destroy() will
 437          * del_timer_sync() this timer after having made sure
 438          * it cannot be readded (by deleting the plink.)
 439          */
 440         sta = (struct sta_info *) data;
 441
 442         if (sta->sdata->local->quiescing) {
 443                 sta->plink_timer_was_running = true;
 444                 return;
 445         }
 446
 447         spin_lock_bh(&sta->lock);
 448         if (sta->ignore_plink_timer) {
 449                 sta->ignore_plink_timer = false;
 450                 spin_unlock_bh(&sta->lock);
 451                 return;
 452         }
 453         mpl_dbg(sta->sdata,
 454                 "Mesh plink timer for %pM fired on state %d\n",
 455                 sta->sta.addr, sta->plink_state);
 456         reason = 0;
 457         llid = sta->llid;
 458         plid = sta->plid;
 459         sdata = sta->sdata;
 460
 461         switch (sta->plink_state) {
 462         case NL80211_PLINK_OPN_RCVD:
 463         case NL80211_PLINK_OPN_SNT:
 464                 /* retry timer */
 465                 if (sta->plink_retries < dot11MeshMaxRetries(sdata)) {
 466                         u32 rand;
 467                         mpl_dbg(sta->sdata,
 468                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 469                                 sta->sta.addr, sta->plink_retries,
 470                                 sta->plink_timeout);
 471                         get_random_bytes(&rand, sizeof(u32));
 472                         sta->plink_timeout = sta->plink_timeout +
 473                                              rand % sta->plink_timeout;
 474                         ++sta->plink_retries;
 475                         mod_plink_timer(sta, sta->plink_timeout);
 476                         spin_unlock_bh(&sta->lock);
 477                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 478                                             sta->sta.addr, llid, 0, 0);
 479                         break;
 480                 }
 481                 reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);
 482                 /* fall through on else */
 483         case NL80211_PLINK_CNF_RCVD:
 484                 /* confirm timer */
 485                 if (!reason)
 486                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);
 487                 sta->plink_state = NL80211_PLINK_HOLDING;
 488                 mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 489                 spin_unlock_bh(&sta->lock);
 490                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 491                                     sta->sta.addr, llid, plid, reason);
 492                 break;
 493         case NL80211_PLINK_HOLDING:
 494                 /* holding timer */
 495                 del_timer(&sta->plink_timer);
 496                 mesh_plink_fsm_restart(sta);
 497                 spin_unlock_bh(&sta->lock);
 498                 break;
 499         default:
 500                 spin_unlock_bh(&sta->lock);
 501                 break;
 502         }
 503 }
 504
 505 #ifdef CONFIG_PM
 506 void mesh_plink_quiesce(struct sta_info *sta)
 507 {
 508         if (del_timer_sync(&sta->plink_timer))
 509                 sta->plink_timer_was_running = true;
 510 }
 511
 512 void mesh_plink_restart(struct sta_info *sta)
 513 {
 514         if (sta->plink_timer_was_running) {
 515                 add_timer(&sta->plink_timer);
 516                 sta->plink_timer_was_running = false;
 517         }
 518 }
 519 #endif
 520
 521 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 522 {
 523         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 524         sta->plink_timer.data = (unsigned long) sta;
 525         sta->plink_timer.function = mesh_plink_timer;
 526         sta->plink_timeout = timeout;
 527         add_timer(&sta->plink_timer);
 528 }
 529
 530 int mesh_plink_open(struct sta_info *sta)
 531 {
 532         __le16 llid;
 533         struct ieee80211_sub_if_data *sdata = sta->sdata;
 534
 535         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 536                 return -EPERM;
 537
 538         spin_lock_bh(&sta->lock);
 539         get_random_bytes(&llid, 2);
 540         sta->llid = llid;
 541         if (sta->plink_state != NL80211_PLINK_LISTEN) {
 542                 spin_unlock_bh(&sta->lock);
 543                 return -EBUSY;
 544         }
 545         sta->plink_state = NL80211_PLINK_OPN_SNT;
 546         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 547         spin_unlock_bh(&sta->lock);
 548         mpl_dbg(sdata,
 549                 "Mesh plink: starting establishment with %pM\n",
 550                 sta->sta.addr);
 551
 552         return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 553                                    sta->sta.addr, llid, 0, 0);
 554 }
 555
 556 void mesh_plink_block(struct sta_info *sta)
 557 {
 558         struct ieee80211_sub_if_data *sdata = sta->sdata;
 559         bool deactivated;
 560
 561         spin_lock_bh(&sta->lock);
 562         deactivated = __mesh_plink_deactivate(sta);
 563         sta->plink_state = NL80211_PLINK_BLOCKED;
 564         spin_unlock_bh(&sta->lock);
 565
 566         if (deactivated)
 567                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 568 }
 569
 570
 571 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,
 572                          size_t len, struct ieee80211_rx_status *rx_status)
 573 {
 574         struct ieee802_11_elems elems;
 575         struct sta_info *sta;
 576         enum plink_event event;
 577         enum ieee80211_self_protected_actioncode ftype;
 578         size_t baselen;
 579         bool matches_local = true;
 580         u8 ie_len;
 581         u8 *baseaddr;
 582         u32 changed = 0;
 583         __le16 plid, llid, reason;
 584         static const char *mplstates[] = {
 585                 [NL80211_PLINK_LISTEN] = "LISTEN",
 586                 [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 587                 [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 588                 [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 589                 [NL80211_PLINK_ESTAB] = "ESTAB",
 590                 [NL80211_PLINK_HOLDING] = "HOLDING",
 591                 [NL80211_PLINK_BLOCKED] = "BLOCKED"
 592         };
 593
 594         /* need action_code, aux */
 595         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
 596                 return;
 597
 598         if (is_multicast_ether_addr(mgmt->da)) {
 599                 mpl_dbg(sdata,
 600                         "Mesh plink: ignore frame from multicast address\n");
 601                 return;
 602         }
 603
 604         baseaddr = mgmt->u.action.u.self_prot.variable;
 605         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
 606         if (mgmt->u.action.u.self_prot.action_code ==
 607                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
 608                 baseaddr += 4;
 609                 baselen += 4;
 610         }
 611         ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
 612         if (!elems.peering) {
 613                 mpl_dbg(sdata,
 614                         "Mesh plink: missing necessary peer link ie\n");
 615                 return;
 616         }
 617         if (elems.rsn_len &&
 618                         sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
 619                 mpl_dbg(sdata,
 620                         "Mesh plink: can't establish link with secure peer\n");
 621                 return;
 622         }
 623
 624         ftype = mgmt->u.action.u.self_prot.action_code;
 625         ie_len = elems.peering_len;
 626         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
 627             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
 628             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
 629                                                         && ie_len != 8)) {
 630                 mpl_dbg(sdata,
 631                         "Mesh plink: incorrect plink ie length %d %d\n",
 632                         ftype, ie_len);
 633                 return;
 634         }
 635
 636         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 637                                 (!elems.mesh_id || !elems.mesh_config)) {
 638                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
 639                 return;
 640         }
 641         /* Note the lines below are correct, the llid in the frame is the plid
 642          * from the point of view of this host.
 643          */
 644         memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
 645         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
 646             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
 647                 memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
 648
 649         rcu_read_lock();
 650
 651         sta = sta_info_get(sdata, mgmt->sa);
 652         if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
 653                 mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 654                 rcu_read_unlock();
 655                 return;
 656         }
 657
 658         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
 659             !rssi_threshold_check(sta, sdata)) {
 660                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
 661                         mgmt->sa);
 662                 rcu_read_unlock();
 663                 return;
 664         }
 665
 666         if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
 667                 mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 668                 rcu_read_unlock();
 669                 return;
 670         }
 671
 672         if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
 673                 rcu_read_unlock();
 674                 return;
 675         }
 676
 677         /* Now we will figure out the appropriate event... */
 678         event = PLINK_UNDEFINED;
 679         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 680             !mesh_matches_local(sdata, &elems)) {
 681                 matches_local = false;
 682                 switch (ftype) {
 683                 case WLAN_SP_MESH_PEERING_OPEN:
 684                         event = OPN_RJCT;
 685                         break;
 686                 case WLAN_SP_MESH_PEERING_CONFIRM:
 687                         event = CNF_RJCT;
 688                         break;
 689                 default:
 690                         break;
 691                 }
 692         }
 693
 694         if (!sta && !matches_local) {
 695                 rcu_read_unlock();
 696                 reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 697                 llid = 0;
 698                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 699                                     mgmt->sa, llid, plid, reason);
 700                 return;
 701         } else if (!sta) {
 702                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 703                 if (!mesh_plink_free_count(sdata)) {
 704                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 705                         rcu_read_unlock();
 706                         return;
 707                 }
 708                 event = OPN_ACPT;
 709         } else if (matches_local) {
 710                 switch (ftype) {
 711                 case WLAN_SP_MESH_PEERING_OPEN:
 712                         if (!mesh_plink_free_count(sdata) ||
 713                             (sta->plid && sta->plid != plid))
 714                                 event = OPN_IGNR;
 715                         else
 716                                 event = OPN_ACPT;
 717                         break;
 718                 case WLAN_SP_MESH_PEERING_CONFIRM:
 719                         if (!mesh_plink_free_count(sdata) ||
 720                             (sta->llid != llid || sta->plid != plid))
 721                                 event = CNF_IGNR;
 722                         else
 723                                 event = CNF_ACPT;
 724                         break;
 725                 case WLAN_SP_MESH_PEERING_CLOSE:
 726                         if (sta->plink_state == NL80211_PLINK_ESTAB)
 727                                 /* Do not check for llid or plid. This does not
 728                                  * follow the standard but since multiple plinks
 729                                  * per sta are not supported, it is necessary in
 730                                  * order to avoid a livelock when MP A sees an
 731                                  * establish peer link to MP B but MP B does not
 732                                  * see it. This can be caused by a timeout in
 733                                  * B's peer link establishment or B beign
 734                                  * restarted.
 735                                  */
 736                                 event = CLS_ACPT;
 737                         else if (sta->plid != plid)
 738                                 event = CLS_IGNR;
 739                         else if (ie_len == 7 && sta->llid != llid)
 740                                 event = CLS_IGNR;
 741                         else
 742                                 event = CLS_ACPT;
 743                         break;
 744                 default:
 745                         mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 746                         rcu_read_unlock();
 747                         return;
 748                 }
 749         }
 750
 751         if (event == OPN_ACPT) {
 752                 /* allocate sta entry if necessary and update info */
 753                 sta = mesh_peer_init(sdata, mgmt->sa, &elems);
 754                 if (!sta) {
 755                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
 756                         rcu_read_unlock();
 757                         return;
 758                 }
 759         }
 760
 761         mpl_dbg(sdata,
 762                 "Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
 763                 mgmt->sa, mplstates[sta->plink_state],
 764                 le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
 765                 event);
 766         reason = 0;
 767         spin_lock_bh(&sta->lock);
 768         switch (sta->plink_state) {
 769                 /* spin_unlock as soon as state is updated at each case */
 770         case NL80211_PLINK_LISTEN:
 771                 switch (event) {
 772                 case CLS_ACPT:
 773                         mesh_plink_fsm_restart(sta);
 774                         spin_unlock_bh(&sta->lock);
 775                         break;
 776                 case OPN_ACPT:
 777                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 778                         sta->plid = plid;
 779                         get_random_bytes(&llid, 2);
 780                         sta->llid = llid;
 781                         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 782                         spin_unlock_bh(&sta->lock);
 783                         mesh_plink_frame_tx(sdata,
 784                                             WLAN_SP_MESH_PEERING_OPEN,
 785                                             sta->sta.addr, llid, 0, 0);
 786                         mesh_plink_frame_tx(sdata,
 787                                             WLAN_SP_MESH_PEERING_CONFIRM,
 788                                             sta->sta.addr, llid, plid, 0);
 789                         break;
 790                 default:
 791                         spin_unlock_bh(&sta->lock);
 792                         break;
 793                 }
 794                 break;
 795
 796         case NL80211_PLINK_OPN_SNT:
 797                 switch (event) {
 798                 case OPN_RJCT:
 799                 case CNF_RJCT:
 800                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 801                 case CLS_ACPT:
 802                         if (!reason)
 803                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 804                         sta->reason = reason;
 805                         sta->plink_state = NL80211_PLINK_HOLDING;
 806                         if (!mod_plink_timer(sta,
 807                                              dot11MeshHoldingTimeout(sdata)))
 808                                 sta->ignore_plink_timer = true;
 809
 810                         llid = sta->llid;
 811                         spin_unlock_bh(&sta->lock);
 812                         mesh_plink_frame_tx(sdata,
 813                                             WLAN_SP_MESH_PEERING_CLOSE,
 814                                             sta->sta.addr, llid, plid, reason);
 815                         break;
 816                 case OPN_ACPT:
 817                         /* retry timer is left untouched */
 818                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 819                         sta->plid = plid;
 820                         llid = sta->llid;
 821                         spin_unlock_bh(&sta->lock);
 822                         mesh_plink_frame_tx(sdata,
 823                                             WLAN_SP_MESH_PEERING_CONFIRM,
 824                                             sta->sta.addr, llid, plid, 0);
 825                         break;
 826                 case CNF_ACPT:
 827                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 828                         if (!mod_plink_timer(sta,
 829                                              dot11MeshConfirmTimeout(sdata)))
 830                                 sta->ignore_plink_timer = true;
 831
 832                         spin_unlock_bh(&sta->lock);
 833                         break;
 834                 default:
 835                         spin_unlock_bh(&sta->lock);
 836                         break;
 837                 }
 838                 break;
 839
 840         case NL80211_PLINK_OPN_RCVD:
 841                 switch (event) {
 842                 case OPN_RJCT:
 843                 case CNF_RJCT:
 844                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 845                 case CLS_ACPT:
 846                         if (!reason)
 847                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 848                         sta->reason = reason;
 849                         sta->plink_state = NL80211_PLINK_HOLDING;
 850                         if (!mod_plink_timer(sta,
 851                                              dot11MeshHoldingTimeout(sdata)))
 852                                 sta->ignore_plink_timer = true;
 853
 854                         llid = sta->llid;
 855                         spin_unlock_bh(&sta->lock);
 856                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 857                                             sta->sta.addr, llid, plid, reason);
 858                         break;
 859                 case OPN_ACPT:
 860                         llid = sta->llid;
 861                         spin_unlock_bh(&sta->lock);
 862                         mesh_plink_frame_tx(sdata,
 863                                             WLAN_SP_MESH_PEERING_CONFIRM,
 864                                             sta->sta.addr, llid, plid, 0);
 865                         break;
 866                 case CNF_ACPT:
 867                         del_timer(&sta->plink_timer);
 868                         sta->plink_state = NL80211_PLINK_ESTAB;
 869                         spin_unlock_bh(&sta->lock);
 870                         mesh_plink_inc_estab_count(sdata);
 871                         changed |= mesh_set_ht_prot_mode(sdata);
 872                         changed |= BSS_CHANGED_BEACON;
 873                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 874                                 sta->sta.addr);
 875                         break;
 876                 default:
 877                         spin_unlock_bh(&sta->lock);
 878                         break;
 879                 }
 880                 break;
 881
 882         case NL80211_PLINK_CNF_RCVD:
 883                 switch (event) {
 884                 case OPN_RJCT:
 885                 case CNF_RJCT:
 886                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 887                 case CLS_ACPT:
 888                         if (!reason)
 889                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 890                         sta->reason = reason;
 891                         sta->plink_state = NL80211_PLINK_HOLDING;
 892                         if (!mod_plink_timer(sta,
 893                                              dot11MeshHoldingTimeout(sdata)))
 894                                 sta->ignore_plink_timer = true;
 895
 896                         llid = sta->llid;
 897                         spin_unlock_bh(&sta->lock);
 898                         mesh_plink_frame_tx(sdata,
 899                                             WLAN_SP_MESH_PEERING_CLOSE,
 900                                             sta->sta.addr, llid, plid, reason);
 901                         break;
 902                 case OPN_ACPT:
 903                         del_timer(&sta->plink_timer);
 904                         sta->plink_state = NL80211_PLINK_ESTAB;
 905                         spin_unlock_bh(&sta->lock);
 906                         mesh_plink_inc_estab_count(sdata);
 907                         changed |= mesh_set_ht_prot_mode(sdata);
 908                         changed |= BSS_CHANGED_BEACON;
 909                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 910                                 sta->sta.addr);
 911                         mesh_plink_frame_tx(sdata,
 912                                             WLAN_SP_MESH_PEERING_CONFIRM,
 913                                             sta->sta.addr, llid, plid, 0);
 914                         break;
 915                 default:
 916                         spin_unlock_bh(&sta->lock);
 917                         break;
 918                 }
 919                 break;
 920
 921         case NL80211_PLINK_ESTAB:
 922                 switch (event) {
 923                 case CLS_ACPT:
 924                         reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 925                         sta->reason = reason;
 926                         __mesh_plink_deactivate(sta);
 927                         sta->plink_state = NL80211_PLINK_HOLDING;
 928                         llid = sta->llid;
 929                         mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 930                         spin_unlock_bh(&sta->lock);
 931                         changed |= mesh_set_ht_prot_mode(sdata);
 932                         changed |= BSS_CHANGED_BEACON;
 933                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 934                                             sta->sta.addr, llid, plid, reason);
 935                         break;
 936                 case OPN_ACPT:
 937                         llid = sta->llid;
 938                         spin_unlock_bh(&sta->lock);
 939                         mesh_plink_frame_tx(sdata,
 940                                             WLAN_SP_MESH_PEERING_CONFIRM,
 941                                             sta->sta.addr, llid, plid, 0);
 942                         break;
 943                 default:
 944                         spin_unlock_bh(&sta->lock);
 945                         break;
 946                 }
 947                 break;
 948         case NL80211_PLINK_HOLDING:
 949                 switch (event) {
 950                 case CLS_ACPT:
 951                         if (del_timer(&sta->plink_timer))
 952                                 sta->ignore_plink_timer = 1;
 953                         mesh_plink_fsm_restart(sta);
 954                         spin_unlock_bh(&sta->lock);
 955                         break;
 956                 case OPN_ACPT:
 957                 case CNF_ACPT:
 958                 case OPN_RJCT:
 959                 case CNF_RJCT:
 960                         llid = sta->llid;
 961                         reason = sta->reason;
 962                         spin_unlock_bh(&sta->lock);
 963                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 964                                             sta->sta.addr, llid, plid, reason);
 965                         break;
 966                 default:
 967                         spin_unlock_bh(&sta->lock);
 968                 }
 969                 break;
 970         default:
 971                 /* should not get here, PLINK_BLOCKED is dealt with at the
 972                  * beginning of the function
 973                  */
 974                 spin_unlock_bh(&sta->lock);
 975                 break;
 976         }
 977
 978         rcu_read_unlock();
 979
 980         if (changed)
 981                 ieee80211_bss_info_change_notify(sdata, changed);
 982 }