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 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  * NOTE: This is just an alias for sta_info_alloc(), see notes
  80  *       on it in the lifecycle management section!
  81  */
  82 static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
  83                                          u8 *hw_addr, u32 rates,
  84                                          struct ieee802_11_elems *elems)
  85 {
  86         struct ieee80211_local *local = sdata->local;
  87         struct ieee80211_supported_band *sband;
  88         struct sta_info *sta;
  89
  90         sband = local->hw.wiphy->bands[local->oper_channel->band];
  91
  92         if (local->num_sta >= MESH_MAX_PLINKS)
  93                 return NULL;
  94
  95         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
  96         if (!sta)
  97                 return NULL;
  98
  99         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 100         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 101         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 102
 103         set_sta_flag(sta, WLAN_STA_WME);
 104
 105         sta->sta.supp_rates[local->hw.conf.channel->band] = rates;
 106         if (elems->ht_cap_elem)
 107                 ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 108                                                   elems->ht_cap_elem,
 109                                                   &sta->sta.ht_cap);
 110         rate_control_rate_init(sta);
 111
 112         return sta;
 113 }
 114
 115 /**
 116  * __mesh_plink_deactivate - deactivate mesh peer link
 117  *
 118  * @sta: mesh peer link to deactivate
 119  *
 120  * All mesh paths with this peer as next hop will be flushed
 121  *
 122  * Locking: the caller must hold sta->lock
 123  */
 124 static bool __mesh_plink_deactivate(struct sta_info *sta)
 125 {
 126         struct ieee80211_sub_if_data *sdata = sta->sdata;
 127         bool deactivated = false;
 128
 129         if (sta->plink_state == NL80211_PLINK_ESTAB) {
 130                 mesh_plink_dec_estab_count(sdata);
 131                 deactivated = true;
 132         }
 133         sta->plink_state = NL80211_PLINK_BLOCKED;
 134         mesh_path_flush_by_nexthop(sta);
 135
 136         return deactivated;
 137 }
 138
 139 /**
 140  * mesh_plink_deactivate - deactivate mesh peer link
 141  *
 142  * @sta: mesh peer link to deactivate
 143  *
 144  * All mesh paths with this peer as next hop will be flushed
 145  */
 146 void mesh_plink_deactivate(struct sta_info *sta)
 147 {
 148         struct ieee80211_sub_if_data *sdata = sta->sdata;
 149         bool deactivated;
 150
 151         spin_lock_bh(&sta->lock);
 152         deactivated = __mesh_plink_deactivate(sta);
 153         sta->reason = cpu_to_le16(WLAN_REASON_MESH_PEER_CANCELED);
 154         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 155                             sta->sta.addr, sta->llid, sta->plid,
 156                             sta->reason);
 157         spin_unlock_bh(&sta->lock);
 158
 159         if (deactivated)
 160                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 161 }
 162
 163 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 164                 enum ieee80211_self_protected_actioncode action,
 165                 u8 *da, __le16 llid, __le16 plid, __le16 reason) {
 166         struct ieee80211_local *local = sdata->local;
 167         struct sk_buff *skb;
 168         struct ieee80211_mgmt *mgmt;
 169         bool include_plid = false;
 170         u16 peering_proto = 0;
 171         u8 *pos, ie_len = 4;
 172         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 173                       sizeof(mgmt->u.action.u.self_prot);
 174
 175         skb = dev_alloc_skb(local->tx_headroom +
 176                             hdr_len +
 177                             2 + /* capability info */
 178                             2 + /* AID */
 179                             2 + 8 + /* supported rates */
 180                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 181                             2 + sdata->u.mesh.mesh_id_len +
 182                             2 + sizeof(struct ieee80211_meshconf_ie) +
 183                             2 + sizeof(struct ieee80211_ht_cap) +
 184                             2 + sizeof(struct ieee80211_ht_info) +
 185                             2 + 8 + /* peering IE */
 186                             sdata->u.mesh.ie_len);
 187         if (!skb)
 188                 return -1;
 189         skb_reserve(skb, local->tx_headroom);
 190         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 191         memset(mgmt, 0, hdr_len);
 192         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 193                                           IEEE80211_STYPE_ACTION);
 194         memcpy(mgmt->da, da, ETH_ALEN);
 195         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 196         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 197         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 198         mgmt->u.action.u.self_prot.action_code = action;
 199
 200         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 201                 /* capability info */
 202                 pos = skb_put(skb, 2);
 203                 memset(pos, 0, 2);
 204                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 205                         /* AID */
 206                         pos = skb_put(skb, 2);
 207                         memcpy(pos + 2, &plid, 2);
 208                 }
 209                 if (ieee80211_add_srates_ie(&sdata->vif, skb) ||
 210                     ieee80211_add_ext_srates_ie(&sdata->vif, skb) ||
 211                     mesh_add_rsn_ie(skb, sdata) ||
 212                     mesh_add_meshid_ie(skb, sdata) ||
 213                     mesh_add_meshconf_ie(skb, sdata))
 214                         return -1;
 215         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 216                 if (mesh_add_meshid_ie(skb, sdata))
 217                         return -1;
 218         }
 219
 220         /* Add Mesh Peering Management element */
 221         switch (action) {
 222         case WLAN_SP_MESH_PEERING_OPEN:
 223                 break;
 224         case WLAN_SP_MESH_PEERING_CONFIRM:
 225                 ie_len += 2;
 226                 include_plid = true;
 227                 break;
 228         case WLAN_SP_MESH_PEERING_CLOSE:
 229                 if (plid) {
 230                         ie_len += 2;
 231                         include_plid = true;
 232                 }
 233                 ie_len += 2;    /* reason code */
 234                 break;
 235         default:
 236                 return -EINVAL;
 237         }
 238
 239         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 240                 return -ENOMEM;
 241
 242         pos = skb_put(skb, 2 + ie_len);
 243         *pos++ = WLAN_EID_PEER_MGMT;
 244         *pos++ = ie_len;
 245         memcpy(pos, &peering_proto, 2);
 246         pos += 2;
 247         memcpy(pos, &llid, 2);
 248         pos += 2;
 249         if (include_plid) {
 250                 memcpy(pos, &plid, 2);
 251                 pos += 2;
 252         }
 253         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 254                 memcpy(pos, &reason, 2);
 255                 pos += 2;
 256         }
 257
 258         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 259                 if (mesh_add_ht_cap_ie(skb, sdata) ||
 260                     mesh_add_ht_info_ie(skb, sdata))
 261                         return -1;
 262         }
 263
 264         if (mesh_add_vendor_ies(skb, sdata))
 265                 return -1;
 266
 267         ieee80211_tx_skb(sdata, skb);
 268         return 0;
 269 }
 270
 271 void mesh_neighbour_update(u8 *hw_addr, u32 rates,
 272                 struct ieee80211_sub_if_data *sdata,
 273                 struct ieee802_11_elems *elems)
 274 {
 275         struct ieee80211_local *local = sdata->local;
 276         struct sta_info *sta;
 277
 278         rcu_read_lock();
 279
 280         sta = sta_info_get(sdata, hw_addr);
 281         if (!sta) {
 282                 rcu_read_unlock();
 283                 /* Userspace handles peer allocation when security is enabled
 284                  * */
 285                 if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
 286                         cfg80211_notify_new_peer_candidate(sdata->dev, hw_addr,
 287                                         elems->ie_start, elems->total_len,
 288                                         GFP_KERNEL);
 289                 else
 290                         sta = mesh_plink_alloc(sdata, hw_addr, rates, elems);
 291                 if (!sta)
 292                         return;
 293                 if (sta_info_insert_rcu(sta)) {
 294                         rcu_read_unlock();
 295                         return;
 296                 }
 297         }
 298
 299         sta->last_rx = jiffies;
 300         sta->sta.supp_rates[local->hw.conf.channel->band] = rates;
 301         if (mesh_peer_accepts_plinks(elems) &&
 302                         sta->plink_state == NL80211_PLINK_LISTEN &&
 303                         sdata->u.mesh.accepting_plinks &&
 304                         sdata->u.mesh.mshcfg.auto_open_plinks)
 305                 mesh_plink_open(sta);
 306
 307         rcu_read_unlock();
 308 }
 309
 310 static void mesh_plink_timer(unsigned long data)
 311 {
 312         struct sta_info *sta;
 313         __le16 llid, plid, reason;
 314         struct ieee80211_sub_if_data *sdata;
 315
 316         /*
 317          * This STA is valid because sta_info_destroy() will
 318          * del_timer_sync() this timer after having made sure
 319          * it cannot be readded (by deleting the plink.)
 320          */
 321         sta = (struct sta_info *) data;
 322
 323         if (sta->sdata->local->quiescing) {
 324                 sta->plink_timer_was_running = true;
 325                 return;
 326         }
 327
 328         spin_lock_bh(&sta->lock);
 329         if (sta->ignore_plink_timer) {
 330                 sta->ignore_plink_timer = false;
 331                 spin_unlock_bh(&sta->lock);
 332                 return;
 333         }
 334         mpl_dbg("Mesh plink timer for %pM fired on state %d\n",
 335                 sta->sta.addr, sta->plink_state);
 336         reason = 0;
 337         llid = sta->llid;
 338         plid = sta->plid;
 339         sdata = sta->sdata;
 340
 341         switch (sta->plink_state) {
 342         case NL80211_PLINK_OPN_RCVD:
 343         case NL80211_PLINK_OPN_SNT:
 344                 /* retry timer */
 345                 if (sta->plink_retries < dot11MeshMaxRetries(sdata)) {
 346                         u32 rand;
 347                         mpl_dbg("Mesh plink for %pM (retry, timeout): %d %d\n",
 348                                 sta->sta.addr, sta->plink_retries,
 349                                 sta->plink_timeout);
 350                         get_random_bytes(&rand, sizeof(u32));
 351                         sta->plink_timeout = sta->plink_timeout +
 352                                              rand % sta->plink_timeout;
 353                         ++sta->plink_retries;
 354                         mod_plink_timer(sta, sta->plink_timeout);
 355                         spin_unlock_bh(&sta->lock);
 356                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 357                                             sta->sta.addr, llid, 0, 0);
 358                         break;
 359                 }
 360                 reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);
 361                 /* fall through on else */
 362         case NL80211_PLINK_CNF_RCVD:
 363                 /* confirm timer */
 364                 if (!reason)
 365                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);
 366                 sta->plink_state = NL80211_PLINK_HOLDING;
 367                 mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 368                 spin_unlock_bh(&sta->lock);
 369                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 370                                     sta->sta.addr, llid, plid, reason);
 371                 break;
 372         case NL80211_PLINK_HOLDING:
 373                 /* holding timer */
 374                 del_timer(&sta->plink_timer);
 375                 mesh_plink_fsm_restart(sta);
 376                 spin_unlock_bh(&sta->lock);
 377                 break;
 378         default:
 379                 spin_unlock_bh(&sta->lock);
 380                 break;
 381         }
 382 }
 383
 384 #ifdef CONFIG_PM
 385 void mesh_plink_quiesce(struct sta_info *sta)
 386 {
 387         if (del_timer_sync(&sta->plink_timer))
 388                 sta->plink_timer_was_running = true;
 389 }
 390
 391 void mesh_plink_restart(struct sta_info *sta)
 392 {
 393         if (sta->plink_timer_was_running) {
 394                 add_timer(&sta->plink_timer);
 395                 sta->plink_timer_was_running = false;
 396         }
 397 }
 398 #endif
 399
 400 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 401 {
 402         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 403         sta->plink_timer.data = (unsigned long) sta;
 404         sta->plink_timer.function = mesh_plink_timer;
 405         sta->plink_timeout = timeout;
 406         add_timer(&sta->plink_timer);
 407 }
 408
 409 int mesh_plink_open(struct sta_info *sta)
 410 {
 411         __le16 llid;
 412         struct ieee80211_sub_if_data *sdata = sta->sdata;
 413
 414         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 415                 return -EPERM;
 416
 417         spin_lock_bh(&sta->lock);
 418         get_random_bytes(&llid, 2);
 419         sta->llid = llid;
 420         if (sta->plink_state != NL80211_PLINK_LISTEN) {
 421                 spin_unlock_bh(&sta->lock);
 422                 return -EBUSY;
 423         }
 424         sta->plink_state = NL80211_PLINK_OPN_SNT;
 425         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 426         spin_unlock_bh(&sta->lock);
 427         mpl_dbg("Mesh plink: starting establishment with %pM\n",
 428                 sta->sta.addr);
 429
 430         return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 431                                    sta->sta.addr, llid, 0, 0);
 432 }
 433
 434 void mesh_plink_block(struct sta_info *sta)
 435 {
 436         struct ieee80211_sub_if_data *sdata = sta->sdata;
 437         bool deactivated;
 438
 439         spin_lock_bh(&sta->lock);
 440         deactivated = __mesh_plink_deactivate(sta);
 441         sta->plink_state = NL80211_PLINK_BLOCKED;
 442         spin_unlock_bh(&sta->lock);
 443
 444         if (deactivated)
 445                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 446 }
 447
 448
 449 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,
 450                          size_t len, struct ieee80211_rx_status *rx_status)
 451 {
 452         struct ieee80211_local *local = sdata->local;
 453         struct ieee802_11_elems elems;
 454         struct sta_info *sta;
 455         enum plink_event event;
 456         enum ieee80211_self_protected_actioncode ftype;
 457         size_t baselen;
 458         bool deactivated, matches_local = true;
 459         u8 ie_len;
 460         u8 *baseaddr;
 461         __le16 plid, llid, reason;
 462 #ifdef CONFIG_MAC80211_VERBOSE_MPL_DEBUG
 463         static const char *mplstates[] = {
 464                 [NL80211_PLINK_LISTEN] = "LISTEN",
 465                 [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 466                 [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 467                 [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 468                 [NL80211_PLINK_ESTAB] = "ESTAB",
 469                 [NL80211_PLINK_HOLDING] = "HOLDING",
 470                 [NL80211_PLINK_BLOCKED] = "BLOCKED"
 471         };
 472 #endif
 473
 474         /* need action_code, aux */
 475         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
 476                 return;
 477
 478         if (is_multicast_ether_addr(mgmt->da)) {
 479                 mpl_dbg("Mesh plink: ignore frame from multicast address");
 480                 return;
 481         }
 482
 483         baseaddr = mgmt->u.action.u.self_prot.variable;
 484         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
 485         if (mgmt->u.action.u.self_prot.action_code ==
 486                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
 487                 baseaddr += 4;
 488                 baselen += 4;
 489         }
 490         ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
 491         if (!elems.peering) {
 492                 mpl_dbg("Mesh plink: missing necessary peer link ie\n");
 493                 return;
 494         }
 495         if (elems.rsn_len &&
 496                         sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
 497                 mpl_dbg("Mesh plink: can't establish link with secure peer\n");
 498                 return;
 499         }
 500
 501         ftype = mgmt->u.action.u.self_prot.action_code;
 502         ie_len = elems.peering_len;
 503         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
 504             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
 505             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
 506                                                         && ie_len != 8)) {
 507                 mpl_dbg("Mesh plink: incorrect plink ie length %d %d\n",
 508                     ftype, ie_len);
 509                 return;
 510         }
 511
 512         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 513                                 (!elems.mesh_id || !elems.mesh_config)) {
 514                 mpl_dbg("Mesh plink: missing necessary ie\n");
 515                 return;
 516         }
 517         /* Note the lines below are correct, the llid in the frame is the plid
 518          * from the point of view of this host.
 519          */
 520         memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
 521         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
 522             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
 523                 memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
 524
 525         rcu_read_lock();
 526
 527         sta = sta_info_get(sdata, mgmt->sa);
 528         if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
 529                 mpl_dbg("Mesh plink: cls or cnf from unknown peer\n");
 530                 rcu_read_unlock();
 531                 return;
 532         }
 533
 534         if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
 535                 mpl_dbg("Mesh plink: Action frame from non-authed peer\n");
 536                 rcu_read_unlock();
 537                 return;
 538         }
 539
 540         if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
 541                 rcu_read_unlock();
 542                 return;
 543         }
 544
 545         /* Now we will figure out the appropriate event... */
 546         event = PLINK_UNDEFINED;
 547         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 548             (!mesh_matches_local(&elems, sdata))) {
 549                 matches_local = false;
 550                 switch (ftype) {
 551                 case WLAN_SP_MESH_PEERING_OPEN:
 552                         event = OPN_RJCT;
 553                         break;
 554                 case WLAN_SP_MESH_PEERING_CONFIRM:
 555                         event = CNF_RJCT;
 556                         break;
 557                 default:
 558                         break;
 559                 }
 560         }
 561
 562         if (!sta && !matches_local) {
 563                 rcu_read_unlock();
 564                 reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 565                 llid = 0;
 566                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 567                                     mgmt->sa, llid, plid, reason);
 568                 return;
 569         } else if (!sta) {
 570                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 571                 u32 rates;
 572
 573                 rcu_read_unlock();
 574
 575                 if (!mesh_plink_free_count(sdata)) {
 576                         mpl_dbg("Mesh plink error: no more free plinks\n");
 577                         return;
 578                 }
 579
 580                 rates = ieee80211_sta_get_rates(local, &elems, rx_status->band);
 581                 sta = mesh_plink_alloc(sdata, mgmt->sa, rates, &elems);
 582                 if (!sta) {
 583                         mpl_dbg("Mesh plink error: plink table full\n");
 584                         return;
 585                 }
 586                 if (sta_info_insert_rcu(sta)) {
 587                         rcu_read_unlock();
 588                         return;
 589                 }
 590                 event = OPN_ACPT;
 591                 spin_lock_bh(&sta->lock);
 592         } else if (matches_local) {
 593                 spin_lock_bh(&sta->lock);
 594                 switch (ftype) {
 595                 case WLAN_SP_MESH_PEERING_OPEN:
 596                         if (!mesh_plink_free_count(sdata) ||
 597                             (sta->plid && sta->plid != plid))
 598                                 event = OPN_IGNR;
 599                         else
 600                                 event = OPN_ACPT;
 601                         break;
 602                 case WLAN_SP_MESH_PEERING_CONFIRM:
 603                         if (!mesh_plink_free_count(sdata) ||
 604                             (sta->llid != llid || sta->plid != plid))
 605                                 event = CNF_IGNR;
 606                         else
 607                                 event = CNF_ACPT;
 608                         break;
 609                 case WLAN_SP_MESH_PEERING_CLOSE:
 610                         if (sta->plink_state == NL80211_PLINK_ESTAB)
 611                                 /* Do not check for llid or plid. This does not
 612                                  * follow the standard but since multiple plinks
 613                                  * per sta are not supported, it is necessary in
 614                                  * order to avoid a livelock when MP A sees an
 615                                  * establish peer link to MP B but MP B does not
 616                                  * see it. This can be caused by a timeout in
 617                                  * B's peer link establishment or B beign
 618                                  * restarted.
 619                                  */
 620                                 event = CLS_ACPT;
 621                         else if (sta->plid != plid)
 622                                 event = CLS_IGNR;
 623                         else if (ie_len == 7 && sta->llid != llid)
 624                                 event = CLS_IGNR;
 625                         else
 626                                 event = CLS_ACPT;
 627                         break;
 628                 default:
 629                         mpl_dbg("Mesh plink: unknown frame subtype\n");
 630                         spin_unlock_bh(&sta->lock);
 631                         rcu_read_unlock();
 632                         return;
 633                 }
 634         } else {
 635                 spin_lock_bh(&sta->lock);
 636         }
 637
 638         mpl_dbg("Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
 639                 mgmt->sa, mplstates[sta->plink_state],
 640                 le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
 641                 event);
 642         reason = 0;
 643         switch (sta->plink_state) {
 644                 /* spin_unlock as soon as state is updated at each case */
 645         case NL80211_PLINK_LISTEN:
 646                 switch (event) {
 647                 case CLS_ACPT:
 648                         mesh_plink_fsm_restart(sta);
 649                         spin_unlock_bh(&sta->lock);
 650                         break;
 651                 case OPN_ACPT:
 652                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 653                         sta->plid = plid;
 654                         get_random_bytes(&llid, 2);
 655                         sta->llid = llid;
 656                         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 657                         spin_unlock_bh(&sta->lock);
 658                         mesh_plink_frame_tx(sdata,
 659                                             WLAN_SP_MESH_PEERING_OPEN,
 660                                             sta->sta.addr, llid, 0, 0);
 661                         mesh_plink_frame_tx(sdata,
 662                                             WLAN_SP_MESH_PEERING_CONFIRM,
 663                                             sta->sta.addr, llid, plid, 0);
 664                         break;
 665                 default:
 666                         spin_unlock_bh(&sta->lock);
 667                         break;
 668                 }
 669                 break;
 670
 671         case NL80211_PLINK_OPN_SNT:
 672                 switch (event) {
 673                 case OPN_RJCT:
 674                 case CNF_RJCT:
 675                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 676                 case CLS_ACPT:
 677                         if (!reason)
 678                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 679                         sta->reason = reason;
 680                         sta->plink_state = NL80211_PLINK_HOLDING;
 681                         if (!mod_plink_timer(sta,
 682                                              dot11MeshHoldingTimeout(sdata)))
 683                                 sta->ignore_plink_timer = true;
 684
 685                         llid = sta->llid;
 686                         spin_unlock_bh(&sta->lock);
 687                         mesh_plink_frame_tx(sdata,
 688                                             WLAN_SP_MESH_PEERING_CLOSE,
 689                                             sta->sta.addr, llid, plid, reason);
 690                         break;
 691                 case OPN_ACPT:
 692                         /* retry timer is left untouched */
 693                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 694                         sta->plid = plid;
 695                         llid = sta->llid;
 696                         spin_unlock_bh(&sta->lock);
 697                         mesh_plink_frame_tx(sdata,
 698                                             WLAN_SP_MESH_PEERING_CONFIRM,
 699                                             sta->sta.addr, llid, plid, 0);
 700                         break;
 701                 case CNF_ACPT:
 702                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 703                         if (!mod_plink_timer(sta,
 704                                              dot11MeshConfirmTimeout(sdata)))
 705                                 sta->ignore_plink_timer = true;
 706
 707                         spin_unlock_bh(&sta->lock);
 708                         break;
 709                 default:
 710                         spin_unlock_bh(&sta->lock);
 711                         break;
 712                 }
 713                 break;
 714
 715         case NL80211_PLINK_OPN_RCVD:
 716                 switch (event) {
 717                 case OPN_RJCT:
 718                 case CNF_RJCT:
 719                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 720                 case CLS_ACPT:
 721                         if (!reason)
 722                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 723                         sta->reason = reason;
 724                         sta->plink_state = NL80211_PLINK_HOLDING;
 725                         if (!mod_plink_timer(sta,
 726                                              dot11MeshHoldingTimeout(sdata)))
 727                                 sta->ignore_plink_timer = true;
 728
 729                         llid = sta->llid;
 730                         spin_unlock_bh(&sta->lock);
 731                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 732                                             sta->sta.addr, llid, plid, reason);
 733                         break;
 734                 case OPN_ACPT:
 735                         llid = sta->llid;
 736                         spin_unlock_bh(&sta->lock);
 737                         mesh_plink_frame_tx(sdata,
 738                                             WLAN_SP_MESH_PEERING_CONFIRM,
 739                                             sta->sta.addr, llid, plid, 0);
 740                         break;
 741                 case CNF_ACPT:
 742                         del_timer(&sta->plink_timer);
 743                         sta->plink_state = NL80211_PLINK_ESTAB;
 744                         spin_unlock_bh(&sta->lock);
 745                         mesh_plink_inc_estab_count(sdata);
 746                         ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 747                         mpl_dbg("Mesh plink with %pM ESTABLISHED\n",
 748                                 sta->sta.addr);
 749                         break;
 750                 default:
 751                         spin_unlock_bh(&sta->lock);
 752                         break;
 753                 }
 754                 break;
 755
 756         case NL80211_PLINK_CNF_RCVD:
 757                 switch (event) {
 758                 case OPN_RJCT:
 759                 case CNF_RJCT:
 760                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 761                 case CLS_ACPT:
 762                         if (!reason)
 763                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 764                         sta->reason = reason;
 765                         sta->plink_state = NL80211_PLINK_HOLDING;
 766                         if (!mod_plink_timer(sta,
 767                                              dot11MeshHoldingTimeout(sdata)))
 768                                 sta->ignore_plink_timer = true;
 769
 770                         llid = sta->llid;
 771                         spin_unlock_bh(&sta->lock);
 772                         mesh_plink_frame_tx(sdata,
 773                                             WLAN_SP_MESH_PEERING_CLOSE,
 774                                             sta->sta.addr, llid, plid, reason);
 775                         break;
 776                 case OPN_ACPT:
 777                         del_timer(&sta->plink_timer);
 778                         sta->plink_state = NL80211_PLINK_ESTAB;
 779                         spin_unlock_bh(&sta->lock);
 780                         mesh_plink_inc_estab_count(sdata);
 781                         ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 782                         mpl_dbg("Mesh plink with %pM ESTABLISHED\n",
 783                                 sta->sta.addr);
 784                         mesh_plink_frame_tx(sdata,
 785                                             WLAN_SP_MESH_PEERING_CONFIRM,
 786                                             sta->sta.addr, llid, plid, 0);
 787                         break;
 788                 default:
 789                         spin_unlock_bh(&sta->lock);
 790                         break;
 791                 }
 792                 break;
 793
 794         case NL80211_PLINK_ESTAB:
 795                 switch (event) {
 796                 case CLS_ACPT:
 797                         reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 798                         sta->reason = reason;
 799                         deactivated = __mesh_plink_deactivate(sta);
 800                         sta->plink_state = NL80211_PLINK_HOLDING;
 801                         llid = sta->llid;
 802                         mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 803                         spin_unlock_bh(&sta->lock);
 804                         if (deactivated)
 805                                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 806                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 807                                             sta->sta.addr, llid, plid, reason);
 808                         break;
 809                 case OPN_ACPT:
 810                         llid = sta->llid;
 811                         spin_unlock_bh(&sta->lock);
 812                         mesh_plink_frame_tx(sdata,
 813                                             WLAN_SP_MESH_PEERING_CONFIRM,
 814                                             sta->sta.addr, llid, plid, 0);
 815                         break;
 816                 default:
 817                         spin_unlock_bh(&sta->lock);
 818                         break;
 819                 }
 820                 break;
 821         case NL80211_PLINK_HOLDING:
 822                 switch (event) {
 823                 case CLS_ACPT:
 824                         if (del_timer(&sta->plink_timer))
 825                                 sta->ignore_plink_timer = 1;
 826                         mesh_plink_fsm_restart(sta);
 827                         spin_unlock_bh(&sta->lock);
 828                         break;
 829                 case OPN_ACPT:
 830                 case CNF_ACPT:
 831                 case OPN_RJCT:
 832                 case CNF_RJCT:
 833                         llid = sta->llid;
 834                         reason = sta->reason;
 835                         spin_unlock_bh(&sta->lock);
 836                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 837                                             sta->sta.addr, llid, plid, reason);
 838                         break;
 839                 default:
 840                         spin_unlock_bh(&sta->lock);
 841                 }
 842                 break;
 843         default:
 844                 /* should not get here, PLINK_BLOCKED is dealt with at the
 845                  * beginning of the function
 846                  */
 847                 spin_unlock_bh(&sta->lock);
 848                 break;
 849         }
 850
 851         rcu_read_unlock();
 852 }