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