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 #ifdef CONFIG_MAC80211_VERBOSE_MPL_DEBUG
  17 #define mpl_dbg(fmt, args...)   printk(KERN_DEBUG fmt, ##args)
  18 #else
  19 #define mpl_dbg(fmt, args...)   do { (void)(0); } while (0)
  20 #endif
  21
  22 #define PLINK_GET_LLID(p) (p + 2)
  23 #define PLINK_GET_PLID(p) (p + 4)
  24
  25 #define mod_plink_timer(s, t) (mod_timer(&s->plink_timer, \
  26                                 jiffies + HZ * t / 1000))
  27
  28 #define dot11MeshMaxRetries(s) (s->u.mesh.mshcfg.dot11MeshMaxRetries)
  29 #define dot11MeshRetryTimeout(s) (s->u.mesh.mshcfg.dot11MeshRetryTimeout)
  30 #define dot11MeshConfirmTimeout(s) (s->u.mesh.mshcfg.dot11MeshConfirmTimeout)
  31 #define dot11MeshHoldingTimeout(s) (s->u.mesh.mshcfg.dot11MeshHoldingTimeout)
  32 #define dot11MeshMaxPeerLinks(s) (s->u.mesh.mshcfg.dot11MeshMaxPeerLinks)
  33
  34 /* We only need a valid sta if user configured a minimum rssi_threshold. */
  35 #define rssi_threshold_check(sta, sdata) \
  36                 (sdata->u.mesh.mshcfg.rssi_threshold == 0 ||\
  37                 (sta && (s8) -ewma_read(&sta->avg_signal) > \
  38                 sdata->u.mesh.mshcfg.rssi_threshold))
  39
  40 enum plink_event {
  41         PLINK_UNDEFINED,
  42         OPN_ACPT,
  43         OPN_RJCT,
  44         OPN_IGNR,
  45         CNF_ACPT,
  46         CNF_RJCT,
  47         CNF_IGNR,
  48         CLS_ACPT,
  49         CLS_IGNR
  50 };
  51
  52 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
  53                 enum ieee80211_self_protected_actioncode action,
  54                 u8 *da, __le16 llid, __le16 plid, __le16 reason);
  55
  56 static inline
  57 void mesh_plink_inc_estab_count(struct ieee80211_sub_if_data *sdata)
  58 {
  59         atomic_inc(&sdata->u.mesh.mshstats.estab_plinks);
  60         mesh_accept_plinks_update(sdata);
  61 }
  62
  63 static inline
  64 void mesh_plink_dec_estab_count(struct ieee80211_sub_if_data *sdata)
  65 {
  66         atomic_dec(&sdata->u.mesh.mshstats.estab_plinks);
  67         mesh_accept_plinks_update(sdata);
  68 }
  69
  70 /**
  71  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  72  *
  73  * @sta: mesh peer link to restart
  74  *
  75  * Locking: this function must be called holding sta->lock
  76  */
  77 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  78 {
  79         sta->plink_state = NL80211_PLINK_LISTEN;
  80         sta->llid = sta->plid = sta->reason = 0;
  81         sta->plink_retries = 0;
  82 }
  83
  84 /*
  85  * NOTE: This is just an alias for sta_info_alloc(), see notes
  86  *       on it in the lifecycle management section!
  87  */
  88 static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
  89                                          u8 *hw_addr, u32 rates,
  90                                          struct ieee802_11_elems *elems)
  91 {
  92         struct ieee80211_local *local = sdata->local;
  93         struct ieee80211_supported_band *sband;
  94         struct sta_info *sta;
  95
  96         sband = local->hw.wiphy->bands[local->oper_channel->band];
  97
  98         if (local->num_sta >= MESH_MAX_PLINKS)
  99                 return NULL;
 100
 101         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 102         if (!sta)
 103                 return NULL;
 104
 105         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 106         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 107         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 108
 109         set_sta_flag(sta, WLAN_STA_WME);
 110
 111         sta->sta.supp_rates[local->hw.conf.channel->band] = rates;
 112         if (elems->ht_cap_elem)
 113                 ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 114                                                   elems->ht_cap_elem,
 115                                                   &sta->sta.ht_cap);
 116         rate_control_rate_init(sta);
 117
 118         return sta;
 119 }
 120
 121 /**
 122  * __mesh_plink_deactivate - deactivate mesh peer link
 123  *
 124  * @sta: mesh peer link to deactivate
 125  *
 126  * All mesh paths with this peer as next hop will be flushed
 127  *
 128  * Locking: the caller must hold sta->lock
 129  */
 130 static bool __mesh_plink_deactivate(struct sta_info *sta)
 131 {
 132         struct ieee80211_sub_if_data *sdata = sta->sdata;
 133         bool deactivated = false;
 134
 135         if (sta->plink_state == NL80211_PLINK_ESTAB) {
 136                 mesh_plink_dec_estab_count(sdata);
 137                 deactivated = true;
 138         }
 139         sta->plink_state = NL80211_PLINK_BLOCKED;
 140         mesh_path_flush_by_nexthop(sta);
 141
 142         return deactivated;
 143 }
 144
 145 /**
 146  * mesh_plink_deactivate - deactivate mesh peer link
 147  *
 148  * @sta: mesh peer link to deactivate
 149  *
 150  * All mesh paths with this peer as next hop will be flushed
 151  */
 152 void mesh_plink_deactivate(struct sta_info *sta)
 153 {
 154         struct ieee80211_sub_if_data *sdata = sta->sdata;
 155         bool deactivated;
 156
 157         spin_lock_bh(&sta->lock);
 158         deactivated = __mesh_plink_deactivate(sta);
 159         sta->reason = cpu_to_le16(WLAN_REASON_MESH_PEER_CANCELED);
 160         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 161                             sta->sta.addr, sta->llid, sta->plid,
 162                             sta->reason);
 163         spin_unlock_bh(&sta->lock);
 164
 165         if (deactivated)
 166                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 167 }
 168
 169 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 170                 enum ieee80211_self_protected_actioncode action,
 171                 u8 *da, __le16 llid, __le16 plid, __le16 reason) {
 172         struct ieee80211_local *local = sdata->local;
 173         struct sk_buff *skb;
 174         struct ieee80211_mgmt *mgmt;
 175         bool include_plid = false;
 176         u16 peering_proto = 0;
 177         u8 *pos, ie_len = 4;
 178         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 179                       sizeof(mgmt->u.action.u.self_prot);
 180
 181         skb = dev_alloc_skb(local->tx_headroom +
 182                             hdr_len +
 183                             2 + /* capability info */
 184                             2 + /* AID */
 185                             2 + 8 + /* supported rates */
 186                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 187                             2 + sdata->u.mesh.mesh_id_len +
 188                             2 + sizeof(struct ieee80211_meshconf_ie) +
 189                             2 + sizeof(struct ieee80211_ht_cap) +
 190                             2 + sizeof(struct ieee80211_ht_operation) +
 191                             2 + 8 + /* peering IE */
 192                             sdata->u.mesh.ie_len);
 193         if (!skb)
 194                 return -1;
 195         skb_reserve(skb, local->tx_headroom);
 196         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 197         memset(mgmt, 0, hdr_len);
 198         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 199                                           IEEE80211_STYPE_ACTION);
 200         memcpy(mgmt->da, da, ETH_ALEN);
 201         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 202         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 203         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 204         mgmt->u.action.u.self_prot.action_code = action;
 205
 206         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 207                 /* capability info */
 208                 pos = skb_put(skb, 2);
 209                 memset(pos, 0, 2);
 210                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 211                         /* AID */
 212                         pos = skb_put(skb, 2);
 213                         memcpy(pos + 2, &plid, 2);
 214                 }
 215                 if (ieee80211_add_srates_ie(&sdata->vif, skb, true) ||
 216                     ieee80211_add_ext_srates_ie(&sdata->vif, skb, true) ||
 217                     mesh_add_rsn_ie(skb, sdata) ||
 218                     mesh_add_meshid_ie(skb, sdata) ||
 219                     mesh_add_meshconf_ie(skb, sdata))
 220                         return -1;
 221         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 222                 if (mesh_add_meshid_ie(skb, sdata))
 223                         return -1;
 224         }
 225
 226         /* Add Mesh Peering Management element */
 227         switch (action) {
 228         case WLAN_SP_MESH_PEERING_OPEN:
 229                 break;
 230         case WLAN_SP_MESH_PEERING_CONFIRM:
 231                 ie_len += 2;
 232                 include_plid = true;
 233                 break;
 234         case WLAN_SP_MESH_PEERING_CLOSE:
 235                 if (plid) {
 236                         ie_len += 2;
 237                         include_plid = true;
 238                 }
 239                 ie_len += 2;    /* reason code */
 240                 break;
 241         default:
 242                 return -EINVAL;
 243         }
 244
 245         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 246                 return -ENOMEM;
 247
 248         pos = skb_put(skb, 2 + ie_len);
 249         *pos++ = WLAN_EID_PEER_MGMT;
 250         *pos++ = ie_len;
 251         memcpy(pos, &peering_proto, 2);
 252         pos += 2;
 253         memcpy(pos, &llid, 2);
 254         pos += 2;
 255         if (include_plid) {
 256                 memcpy(pos, &plid, 2);
 257                 pos += 2;
 258         }
 259         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 260                 memcpy(pos, &reason, 2);
 261                 pos += 2;
 262         }
 263
 264         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 265                 if (mesh_add_ht_cap_ie(skb, sdata) ||
 266                     mesh_add_ht_oper_ie(skb, sdata))
 267                         return -1;
 268         }
 269
 270         if (mesh_add_vendor_ies(skb, sdata))
 271                 return -1;
 272
 273         ieee80211_tx_skb(sdata, skb);
 274         return 0;
 275 }
 276
 277 void mesh_neighbour_update(u8 *hw_addr, u32 rates,
 278                 struct ieee80211_sub_if_data *sdata,
 279                 struct ieee802_11_elems *elems)
 280 {
 281         struct ieee80211_local *local = sdata->local;
 282         struct sta_info *sta;
 283
 284         rcu_read_lock();
 285
 286         sta = sta_info_get(sdata, hw_addr);
 287         if (!sta) {
 288                 rcu_read_unlock();
 289                 /* Userspace handles peer allocation when security is enabled
 290                  * */
 291                 if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
 292                         cfg80211_notify_new_peer_candidate(sdata->dev, hw_addr,
 293                                         elems->ie_start, elems->total_len,
 294                                         GFP_KERNEL);
 295                 else
 296                         sta = mesh_plink_alloc(sdata, hw_addr, rates, elems);
 297                 if (!sta)
 298                         return;
 299                 if (sta_info_insert_rcu(sta)) {
 300                         rcu_read_unlock();
 301                         return;
 302                 }
 303         }
 304
 305         sta->last_rx = jiffies;
 306         sta->sta.supp_rates[local->hw.conf.channel->band] = rates;
 307         if (mesh_peer_accepts_plinks(elems) &&
 308                         sta->plink_state == NL80211_PLINK_LISTEN &&
 309                         sdata->u.mesh.accepting_plinks &&
 310                         sdata->u.mesh.mshcfg.auto_open_plinks &&
 311                         rssi_threshold_check(sta, sdata))
 312                 mesh_plink_open(sta);
 313
 314         rcu_read_unlock();
 315 }
 316
 317 static void mesh_plink_timer(unsigned long data)
 318 {
 319         struct sta_info *sta;
 320         __le16 llid, plid, reason;
 321         struct ieee80211_sub_if_data *sdata;
 322
 323         /*
 324          * This STA is valid because sta_info_destroy() will
 325          * del_timer_sync() this timer after having made sure
 326          * it cannot be readded (by deleting the plink.)
 327          */
 328         sta = (struct sta_info *) data;
 329
 330         if (sta->sdata->local->quiescing) {
 331                 sta->plink_timer_was_running = true;
 332                 return;
 333         }
 334
 335         spin_lock_bh(&sta->lock);
 336         if (sta->ignore_plink_timer) {
 337                 sta->ignore_plink_timer = false;
 338                 spin_unlock_bh(&sta->lock);
 339                 return;
 340         }
 341         mpl_dbg("Mesh plink timer for %pM fired on state %d\n",
 342                 sta->sta.addr, sta->plink_state);
 343         reason = 0;
 344         llid = sta->llid;
 345         plid = sta->plid;
 346         sdata = sta->sdata;
 347
 348         switch (sta->plink_state) {
 349         case NL80211_PLINK_OPN_RCVD:
 350         case NL80211_PLINK_OPN_SNT:
 351                 /* retry timer */
 352                 if (sta->plink_retries < dot11MeshMaxRetries(sdata)) {
 353                         u32 rand;
 354                         mpl_dbg("Mesh plink for %pM (retry, timeout): %d %d\n",
 355                                 sta->sta.addr, sta->plink_retries,
 356                                 sta->plink_timeout);
 357                         get_random_bytes(&rand, sizeof(u32));
 358                         sta->plink_timeout = sta->plink_timeout +
 359                                              rand % sta->plink_timeout;
 360                         ++sta->plink_retries;
 361                         mod_plink_timer(sta, sta->plink_timeout);
 362                         spin_unlock_bh(&sta->lock);
 363                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 364                                             sta->sta.addr, llid, 0, 0);
 365                         break;
 366                 }
 367                 reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);
 368                 /* fall through on else */
 369         case NL80211_PLINK_CNF_RCVD:
 370                 /* confirm timer */
 371                 if (!reason)
 372                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);
 373                 sta->plink_state = NL80211_PLINK_HOLDING;
 374                 mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 375                 spin_unlock_bh(&sta->lock);
 376                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 377                                     sta->sta.addr, llid, plid, reason);
 378                 break;
 379         case NL80211_PLINK_HOLDING:
 380                 /* holding timer */
 381                 del_timer(&sta->plink_timer);
 382                 mesh_plink_fsm_restart(sta);
 383                 spin_unlock_bh(&sta->lock);
 384                 break;
 385         default:
 386                 spin_unlock_bh(&sta->lock);
 387                 break;
 388         }
 389 }
 390
 391 #ifdef CONFIG_PM
 392 void mesh_plink_quiesce(struct sta_info *sta)
 393 {
 394         if (del_timer_sync(&sta->plink_timer))
 395                 sta->plink_timer_was_running = true;
 396 }
 397
 398 void mesh_plink_restart(struct sta_info *sta)
 399 {
 400         if (sta->plink_timer_was_running) {
 401                 add_timer(&sta->plink_timer);
 402                 sta->plink_timer_was_running = false;
 403         }
 404 }
 405 #endif
 406
 407 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 408 {
 409         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 410         sta->plink_timer.data = (unsigned long) sta;
 411         sta->plink_timer.function = mesh_plink_timer;
 412         sta->plink_timeout = timeout;
 413         add_timer(&sta->plink_timer);
 414 }
 415
 416 int mesh_plink_open(struct sta_info *sta)
 417 {
 418         __le16 llid;
 419         struct ieee80211_sub_if_data *sdata = sta->sdata;
 420
 421         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 422                 return -EPERM;
 423
 424         spin_lock_bh(&sta->lock);
 425         get_random_bytes(&llid, 2);
 426         sta->llid = llid;
 427         if (sta->plink_state != NL80211_PLINK_LISTEN) {
 428                 spin_unlock_bh(&sta->lock);
 429                 return -EBUSY;
 430         }
 431         sta->plink_state = NL80211_PLINK_OPN_SNT;
 432         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 433         spin_unlock_bh(&sta->lock);
 434         mpl_dbg("Mesh plink: starting establishment with %pM\n",
 435                 sta->sta.addr);
 436
 437         return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 438                                    sta->sta.addr, llid, 0, 0);
 439 }
 440
 441 void mesh_plink_block(struct sta_info *sta)
 442 {
 443         struct ieee80211_sub_if_data *sdata = sta->sdata;
 444         bool deactivated;
 445
 446         spin_lock_bh(&sta->lock);
 447         deactivated = __mesh_plink_deactivate(sta);
 448         sta->plink_state = NL80211_PLINK_BLOCKED;
 449         spin_unlock_bh(&sta->lock);
 450
 451         if (deactivated)
 452                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 453 }
 454
 455
 456 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,
 457                          size_t len, struct ieee80211_rx_status *rx_status)
 458 {
 459         struct ieee80211_local *local = sdata->local;
 460         struct ieee802_11_elems elems;
 461         struct sta_info *sta;
 462         enum plink_event event;
 463         enum ieee80211_self_protected_actioncode ftype;
 464         size_t baselen;
 465         bool deactivated, matches_local = true;
 466         u8 ie_len;
 467         u8 *baseaddr;
 468         __le16 plid, llid, reason;
 469 #ifdef CONFIG_MAC80211_VERBOSE_MPL_DEBUG
 470         static const char *mplstates[] = {
 471                 [NL80211_PLINK_LISTEN] = "LISTEN",
 472                 [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 473                 [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 474                 [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 475                 [NL80211_PLINK_ESTAB] = "ESTAB",
 476                 [NL80211_PLINK_HOLDING] = "HOLDING",
 477                 [NL80211_PLINK_BLOCKED] = "BLOCKED"
 478         };
 479 #endif
 480
 481         /* need action_code, aux */
 482         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
 483                 return;
 484
 485         if (is_multicast_ether_addr(mgmt->da)) {
 486                 mpl_dbg("Mesh plink: ignore frame from multicast address");
 487                 return;
 488         }
 489
 490         baseaddr = mgmt->u.action.u.self_prot.variable;
 491         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
 492         if (mgmt->u.action.u.self_prot.action_code ==
 493                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
 494                 baseaddr += 4;
 495                 baselen += 4;
 496         }
 497         ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
 498         if (!elems.peering) {
 499                 mpl_dbg("Mesh plink: missing necessary peer link ie\n");
 500                 return;
 501         }
 502         if (elems.rsn_len &&
 503                         sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
 504                 mpl_dbg("Mesh plink: can't establish link with secure peer\n");
 505                 return;
 506         }
 507
 508         ftype = mgmt->u.action.u.self_prot.action_code;
 509         ie_len = elems.peering_len;
 510         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
 511             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
 512             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
 513                                                         && ie_len != 8)) {
 514                 mpl_dbg("Mesh plink: incorrect plink ie length %d %d\n",
 515                     ftype, ie_len);
 516                 return;
 517         }
 518
 519         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 520                                 (!elems.mesh_id || !elems.mesh_config)) {
 521                 mpl_dbg("Mesh plink: missing necessary ie\n");
 522                 return;
 523         }
 524         /* Note the lines below are correct, the llid in the frame is the plid
 525          * from the point of view of this host.
 526          */
 527         memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
 528         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
 529             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
 530                 memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
 531
 532         rcu_read_lock();
 533
 534         sta = sta_info_get(sdata, mgmt->sa);
 535         if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
 536                 mpl_dbg("Mesh plink: cls or cnf from unknown peer\n");
 537                 rcu_read_unlock();
 538                 return;
 539         }
 540
 541         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
 542             !rssi_threshold_check(sta, sdata)) {
 543                 mpl_dbg("Mesh plink: %pM does not meet rssi threshold\n",
 544                         mgmt->sa);
 545                 rcu_read_unlock();
 546                 return;
 547         }
 548
 549         if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
 550                 mpl_dbg("Mesh plink: Action frame from non-authed peer\n");
 551                 rcu_read_unlock();
 552                 return;
 553         }
 554
 555         if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
 556                 rcu_read_unlock();
 557                 return;
 558         }
 559
 560         /* Now we will figure out the appropriate event... */
 561         event = PLINK_UNDEFINED;
 562         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 563             (!mesh_matches_local(&elems, sdata))) {
 564                 matches_local = false;
 565                 switch (ftype) {
 566                 case WLAN_SP_MESH_PEERING_OPEN:
 567                         event = OPN_RJCT;
 568                         break;
 569                 case WLAN_SP_MESH_PEERING_CONFIRM:
 570                         event = CNF_RJCT;
 571                         break;
 572                 default:
 573                         break;
 574                 }
 575         }
 576
 577         if (!sta && !matches_local) {
 578                 rcu_read_unlock();
 579                 reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 580                 llid = 0;
 581                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 582                                     mgmt->sa, llid, plid, reason);
 583                 return;
 584         } else if (!sta) {
 585                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 586                 u32 rates;
 587
 588                 rcu_read_unlock();
 589
 590                 if (!mesh_plink_free_count(sdata)) {
 591                         mpl_dbg("Mesh plink error: no more free plinks\n");
 592                         return;
 593                 }
 594
 595                 rates = ieee80211_sta_get_rates(local, &elems, rx_status->band);
 596                 sta = mesh_plink_alloc(sdata, mgmt->sa, rates, &elems);
 597                 if (!sta) {
 598                         mpl_dbg("Mesh plink error: plink table full\n");
 599                         return;
 600                 }
 601                 if (sta_info_insert_rcu(sta)) {
 602                         rcu_read_unlock();
 603                         return;
 604                 }
 605                 event = OPN_ACPT;
 606                 spin_lock_bh(&sta->lock);
 607         } else if (matches_local) {
 608                 spin_lock_bh(&sta->lock);
 609                 switch (ftype) {
 610                 case WLAN_SP_MESH_PEERING_OPEN:
 611                         if (!mesh_plink_free_count(sdata) ||
 612                             (sta->plid && sta->plid != plid))
 613                                 event = OPN_IGNR;
 614                         else
 615                                 event = OPN_ACPT;
 616                         break;
 617                 case WLAN_SP_MESH_PEERING_CONFIRM:
 618                         if (!mesh_plink_free_count(sdata) ||
 619                             (sta->llid != llid || sta->plid != plid))
 620                                 event = CNF_IGNR;
 621                         else
 622                                 event = CNF_ACPT;
 623                         break;
 624                 case WLAN_SP_MESH_PEERING_CLOSE:
 625                         if (sta->plink_state == NL80211_PLINK_ESTAB)
 626                                 /* Do not check for llid or plid. This does not
 627                                  * follow the standard but since multiple plinks
 628                                  * per sta are not supported, it is necessary in
 629                                  * order to avoid a livelock when MP A sees an
 630                                  * establish peer link to MP B but MP B does not
 631                                  * see it. This can be caused by a timeout in
 632                                  * B's peer link establishment or B beign
 633                                  * restarted.
 634                                  */
 635                                 event = CLS_ACPT;
 636                         else if (sta->plid != plid)
 637                                 event = CLS_IGNR;
 638                         else if (ie_len == 7 && sta->llid != llid)
 639                                 event = CLS_IGNR;
 640                         else
 641                                 event = CLS_ACPT;
 642                         break;
 643                 default:
 644                         mpl_dbg("Mesh plink: unknown frame subtype\n");
 645                         spin_unlock_bh(&sta->lock);
 646                         rcu_read_unlock();
 647                         return;
 648                 }
 649         } else {
 650                 spin_lock_bh(&sta->lock);
 651         }
 652
 653         mpl_dbg("Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
 654                 mgmt->sa, mplstates[sta->plink_state],
 655                 le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
 656                 event);
 657         reason = 0;
 658         switch (sta->plink_state) {
 659                 /* spin_unlock as soon as state is updated at each case */
 660         case NL80211_PLINK_LISTEN:
 661                 switch (event) {
 662                 case CLS_ACPT:
 663                         mesh_plink_fsm_restart(sta);
 664                         spin_unlock_bh(&sta->lock);
 665                         break;
 666                 case OPN_ACPT:
 667                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 668                         sta->plid = plid;
 669                         get_random_bytes(&llid, 2);
 670                         sta->llid = llid;
 671                         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 672                         spin_unlock_bh(&sta->lock);
 673                         mesh_plink_frame_tx(sdata,
 674                                             WLAN_SP_MESH_PEERING_OPEN,
 675                                             sta->sta.addr, llid, 0, 0);
 676                         mesh_plink_frame_tx(sdata,
 677                                             WLAN_SP_MESH_PEERING_CONFIRM,
 678                                             sta->sta.addr, llid, plid, 0);
 679                         break;
 680                 default:
 681                         spin_unlock_bh(&sta->lock);
 682                         break;
 683                 }
 684                 break;
 685
 686         case NL80211_PLINK_OPN_SNT:
 687                 switch (event) {
 688                 case OPN_RJCT:
 689                 case CNF_RJCT:
 690                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 691                 case CLS_ACPT:
 692                         if (!reason)
 693                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 694                         sta->reason = reason;
 695                         sta->plink_state = NL80211_PLINK_HOLDING;
 696                         if (!mod_plink_timer(sta,
 697                                              dot11MeshHoldingTimeout(sdata)))
 698                                 sta->ignore_plink_timer = true;
 699
 700                         llid = sta->llid;
 701                         spin_unlock_bh(&sta->lock);
 702                         mesh_plink_frame_tx(sdata,
 703                                             WLAN_SP_MESH_PEERING_CLOSE,
 704                                             sta->sta.addr, llid, plid, reason);
 705                         break;
 706                 case OPN_ACPT:
 707                         /* retry timer is left untouched */
 708                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 709                         sta->plid = plid;
 710                         llid = sta->llid;
 711                         spin_unlock_bh(&sta->lock);
 712                         mesh_plink_frame_tx(sdata,
 713                                             WLAN_SP_MESH_PEERING_CONFIRM,
 714                                             sta->sta.addr, llid, plid, 0);
 715                         break;
 716                 case CNF_ACPT:
 717                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 718                         if (!mod_plink_timer(sta,
 719                                              dot11MeshConfirmTimeout(sdata)))
 720                                 sta->ignore_plink_timer = true;
 721
 722                         spin_unlock_bh(&sta->lock);
 723                         break;
 724                 default:
 725                         spin_unlock_bh(&sta->lock);
 726                         break;
 727                 }
 728                 break;
 729
 730         case NL80211_PLINK_OPN_RCVD:
 731                 switch (event) {
 732                 case OPN_RJCT:
 733                 case CNF_RJCT:
 734                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 735                 case CLS_ACPT:
 736                         if (!reason)
 737                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 738                         sta->reason = reason;
 739                         sta->plink_state = NL80211_PLINK_HOLDING;
 740                         if (!mod_plink_timer(sta,
 741                                              dot11MeshHoldingTimeout(sdata)))
 742                                 sta->ignore_plink_timer = true;
 743
 744                         llid = sta->llid;
 745                         spin_unlock_bh(&sta->lock);
 746                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 747                                             sta->sta.addr, llid, plid, reason);
 748                         break;
 749                 case OPN_ACPT:
 750                         llid = sta->llid;
 751                         spin_unlock_bh(&sta->lock);
 752                         mesh_plink_frame_tx(sdata,
 753                                             WLAN_SP_MESH_PEERING_CONFIRM,
 754                                             sta->sta.addr, llid, plid, 0);
 755                         break;
 756                 case CNF_ACPT:
 757                         del_timer(&sta->plink_timer);
 758                         sta->plink_state = NL80211_PLINK_ESTAB;
 759                         spin_unlock_bh(&sta->lock);
 760                         mesh_plink_inc_estab_count(sdata);
 761                         ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 762                         mpl_dbg("Mesh plink with %pM ESTABLISHED\n",
 763                                 sta->sta.addr);
 764                         break;
 765                 default:
 766                         spin_unlock_bh(&sta->lock);
 767                         break;
 768                 }
 769                 break;
 770
 771         case NL80211_PLINK_CNF_RCVD:
 772                 switch (event) {
 773                 case OPN_RJCT:
 774                 case CNF_RJCT:
 775                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 776                 case CLS_ACPT:
 777                         if (!reason)
 778                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 779                         sta->reason = reason;
 780                         sta->plink_state = NL80211_PLINK_HOLDING;
 781                         if (!mod_plink_timer(sta,
 782                                              dot11MeshHoldingTimeout(sdata)))
 783                                 sta->ignore_plink_timer = true;
 784
 785                         llid = sta->llid;
 786                         spin_unlock_bh(&sta->lock);
 787                         mesh_plink_frame_tx(sdata,
 788                                             WLAN_SP_MESH_PEERING_CLOSE,
 789                                             sta->sta.addr, llid, plid, reason);
 790                         break;
 791                 case OPN_ACPT:
 792                         del_timer(&sta->plink_timer);
 793                         sta->plink_state = NL80211_PLINK_ESTAB;
 794                         spin_unlock_bh(&sta->lock);
 795                         mesh_plink_inc_estab_count(sdata);
 796                         ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 797                         mpl_dbg("Mesh plink with %pM ESTABLISHED\n",
 798                                 sta->sta.addr);
 799                         mesh_plink_frame_tx(sdata,
 800                                             WLAN_SP_MESH_PEERING_CONFIRM,
 801                                             sta->sta.addr, llid, plid, 0);
 802                         break;
 803                 default:
 804                         spin_unlock_bh(&sta->lock);
 805                         break;
 806                 }
 807                 break;
 808
 809         case NL80211_PLINK_ESTAB:
 810                 switch (event) {
 811                 case CLS_ACPT:
 812                         reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 813                         sta->reason = reason;
 814                         deactivated = __mesh_plink_deactivate(sta);
 815                         sta->plink_state = NL80211_PLINK_HOLDING;
 816                         llid = sta->llid;
 817                         mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 818                         spin_unlock_bh(&sta->lock);
 819                         if (deactivated)
 820                                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 821                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 822                                             sta->sta.addr, llid, plid, reason);
 823                         break;
 824                 case OPN_ACPT:
 825                         llid = sta->llid;
 826                         spin_unlock_bh(&sta->lock);
 827                         mesh_plink_frame_tx(sdata,
 828                                             WLAN_SP_MESH_PEERING_CONFIRM,
 829                                             sta->sta.addr, llid, plid, 0);
 830                         break;
 831                 default:
 832                         spin_unlock_bh(&sta->lock);
 833                         break;
 834                 }
 835                 break;
 836         case NL80211_PLINK_HOLDING:
 837                 switch (event) {
 838                 case CLS_ACPT:
 839                         if (del_timer(&sta->plink_timer))
 840                                 sta->ignore_plink_timer = 1;
 841                         mesh_plink_fsm_restart(sta);
 842                         spin_unlock_bh(&sta->lock);
 843                         break;
 844                 case OPN_ACPT:
 845                 case CNF_ACPT:
 846                 case OPN_RJCT:
 847                 case CNF_RJCT:
 848                         llid = sta->llid;
 849                         reason = sta->reason;
 850                         spin_unlock_bh(&sta->lock);
 851                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 852                                             sta->sta.addr, llid, plid, reason);
 853                         break;
 854                 default:
 855                         spin_unlock_bh(&sta->lock);
 856                 }
 857                 break;
 858         default:
 859                 /* should not get here, PLINK_BLOCKED is dealt with at the
 860                  * beginning of the function
 861                  */
 862                 spin_unlock_bh(&sta->lock);
 863                 break;
 864         }
 865
 866         rcu_read_unlock();
 867 }