net/mac80211/mesh_plink.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9 #include <linux/gfp.h>
  10 #include <linux/kernel.h>
  11 #include <linux/random.h>
  12 #include "ieee80211_i.h"
  13 #include "rate.h"
  14 #include "mesh.h"
  15
  16 #define PLINK_GET_LLID(p) (p + 2)
  17 #define PLINK_GET_PLID(p) (p + 4)
  18
  19 #define mod_plink_timer(s, t) (mod_timer(&s->plink_timer, \
  20                                 jiffies + HZ * t / 1000))
  21
  22 #define dot11MeshMaxRetries(s) (s->u.mesh.mshcfg.dot11MeshMaxRetries)
  23 #define dot11MeshRetryTimeout(s) (s->u.mesh.mshcfg.dot11MeshRetryTimeout)
  24 #define dot11MeshConfirmTimeout(s) (s->u.mesh.mshcfg.dot11MeshConfirmTimeout)
  25 #define dot11MeshHoldingTimeout(s) (s->u.mesh.mshcfg.dot11MeshHoldingTimeout)
  26 #define dot11MeshMaxPeerLinks(s) (s->u.mesh.mshcfg.dot11MeshMaxPeerLinks)
  27
  28 /* We only need a valid sta if user configured a minimum rssi_threshold. */
  29 #define rssi_threshold_check(sta, sdata) \
  30                 (sdata->u.mesh.mshcfg.rssi_threshold == 0 ||\
  31                 (sta && (s8) -ewma_read(&sta->avg_signal) > \
  32                 sdata->u.mesh.mshcfg.rssi_threshold))
  33
  34 enum plink_event {
  35         PLINK_UNDEFINED,
  36         OPN_ACPT,
  37         OPN_RJCT,
  38         OPN_IGNR,
  39         CNF_ACPT,
  40         CNF_RJCT,
  41         CNF_IGNR,
  42         CLS_ACPT,
  43         CLS_IGNR
  44 };
  45
  46 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
  47                 enum ieee80211_self_protected_actioncode action,
  48                 u8 *da, __le16 llid, __le16 plid, __le16 reason);
  49
  50 static inline
  51 u32 mesh_plink_inc_estab_count(struct ieee80211_sub_if_data *sdata)
  52 {
  53         atomic_inc(&sdata->u.mesh.mshstats.estab_plinks);
  54         return mesh_accept_plinks_update(sdata);
  55 }
  56
  57 static inline
  58 u32 mesh_plink_dec_estab_count(struct ieee80211_sub_if_data *sdata)
  59 {
  60         atomic_dec(&sdata->u.mesh.mshstats.estab_plinks);
  61         return mesh_accept_plinks_update(sdata);
  62 }
  63
  64 /**
  65  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  66  *
  67  * @sta: mesh peer link to restart
  68  *
  69  * Locking: this function must be called holding sta->lock
  70  */
  71 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  72 {
  73         sta->plink_state = NL80211_PLINK_LISTEN;
  74         sta->llid = sta->plid = sta->reason = 0;
  75         sta->plink_retries = 0;
  76 }
  77
  78 /*
  79  * Allocate mesh sta entry and insert into station table
  80  */
  81 static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
  82                                          u8 *hw_addr)
  83 {
  84         struct sta_info *sta;
  85
  86         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
  87                 return NULL;
  88
  89         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
  90         if (!sta)
  91                 return NULL;
  92
  93         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
  94         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
  95         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
  96
  97         set_sta_flag(sta, WLAN_STA_WME);
  98
  99         return sta;
 100 }
 101
 102 /**
 103  * mesh_set_ht_prot_mode - set correct HT protection mode
 104  *
 105  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 106  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 107  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 108  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 109  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 110  * HT20 peer is present. Otherwise no-protection mode is selected.
 111  */
 112 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 113 {
 114         struct ieee80211_local *local = sdata->local;
 115         struct sta_info *sta;
 116         u32 changed = 0;
 117         u16 ht_opmode;
 118         bool non_ht_sta = false, ht20_sta = false;
 119
 120         if (sdata->vif.bss_conf.channel_type == NL80211_CHAN_NO_HT)
 121                 return 0;
 122
 123         rcu_read_lock();
 124         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 125                 if (sdata != sta->sdata ||
 126                     sta->plink_state != NL80211_PLINK_ESTAB)
 127                         continue;
 128
 129                 switch (sta->ch_type) {
 130                 case NL80211_CHAN_NO_HT:
 131                         mpl_dbg(sdata,
 132                                 "mesh_plink %pM: nonHT sta (%pM) is present\n",
 133                                 sdata->vif.addr, sta->sta.addr);
 134                         non_ht_sta = true;
 135                         goto out;
 136                 case NL80211_CHAN_HT20:
 137                         mpl_dbg(sdata,
 138                                 "mesh_plink %pM: HT20 sta (%pM) is present\n",
 139                                 sdata->vif.addr, sta->sta.addr);
 140                         ht20_sta = true;
 141                 default:
 142                         break;
 143                 }
 144         }
 145 out:
 146         rcu_read_unlock();
 147
 148         if (non_ht_sta)
 149                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 150         else if (ht20_sta &&
 151                  sdata->vif.bss_conf.channel_type > NL80211_CHAN_HT20)
 152                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 153         else
 154                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 155
 156         if (sdata->vif.bss_conf.ht_operation_mode != ht_opmode) {
 157                 sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 158                 sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 159                 changed = BSS_CHANGED_HT;
 160                 mpl_dbg(sdata,
 161                         "mesh_plink %pM: protection mode changed to %d\n",
 162                         sdata->vif.addr, ht_opmode);
 163         }
 164
 165         return changed;
 166 }
 167
 168 /**
 169  * __mesh_plink_deactivate - deactivate mesh peer link
 170  *
 171  * @sta: mesh peer link to deactivate
 172  *
 173  * All mesh paths with this peer as next hop will be flushed
 174  * Returns beacon changed flag if the beacon content changed.
 175  *
 176  * Locking: the caller must hold sta->lock
 177  */
 178 static u32 __mesh_plink_deactivate(struct sta_info *sta)
 179 {
 180         struct ieee80211_sub_if_data *sdata = sta->sdata;
 181         u32 changed = 0;
 182
 183         if (sta->plink_state == NL80211_PLINK_ESTAB)
 184                 changed = mesh_plink_dec_estab_count(sdata);
 185         sta->plink_state = NL80211_PLINK_BLOCKED;
 186         mesh_path_flush_by_nexthop(sta);
 187
 188         return changed;
 189 }
 190
 191 /**
 192  * mesh_plink_deactivate - deactivate mesh peer link
 193  *
 194  * @sta: mesh peer link to deactivate
 195  *
 196  * All mesh paths with this peer as next hop will be flushed
 197  */
 198 void mesh_plink_deactivate(struct sta_info *sta)
 199 {
 200         struct ieee80211_sub_if_data *sdata = sta->sdata;
 201         u32 changed;
 202
 203         spin_lock_bh(&sta->lock);
 204         changed = __mesh_plink_deactivate(sta);
 205         sta->reason = cpu_to_le16(WLAN_REASON_MESH_PEER_CANCELED);
 206         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 207                             sta->sta.addr, sta->llid, sta->plid,
 208                             sta->reason);
 209         spin_unlock_bh(&sta->lock);
 210
 211         ieee80211_bss_info_change_notify(sdata, changed);
 212 }
 213
 214 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 215                 enum ieee80211_self_protected_actioncode action,
 216                 u8 *da, __le16 llid, __le16 plid, __le16 reason) {
 217         struct ieee80211_local *local = sdata->local;
 218         struct sk_buff *skb;
 219         struct ieee80211_tx_info *info;
 220         struct ieee80211_mgmt *mgmt;
 221         bool include_plid = false;
 222         u16 peering_proto = 0;
 223         u8 *pos, ie_len = 4;
 224         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 225                       sizeof(mgmt->u.action.u.self_prot);
 226         int err = -ENOMEM;
 227
 228         skb = dev_alloc_skb(local->tx_headroom +
 229                             hdr_len +
 230                             2 + /* capability info */
 231                             2 + /* AID */
 232                             2 + 8 + /* supported rates */
 233                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 234                             2 + sdata->u.mesh.mesh_id_len +
 235                             2 + sizeof(struct ieee80211_meshconf_ie) +
 236                             2 + sizeof(struct ieee80211_ht_cap) +
 237                             2 + sizeof(struct ieee80211_ht_operation) +
 238                             2 + 8 + /* peering IE */
 239                             sdata->u.mesh.ie_len);
 240         if (!skb)
 241                 return -1;
 242         info = IEEE80211_SKB_CB(skb);
 243         skb_reserve(skb, local->tx_headroom);
 244         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 245         memset(mgmt, 0, hdr_len);
 246         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 247                                           IEEE80211_STYPE_ACTION);
 248         memcpy(mgmt->da, da, ETH_ALEN);
 249         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 250         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 251         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 252         mgmt->u.action.u.self_prot.action_code = action;
 253
 254         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 255                 /* capability info */
 256                 pos = skb_put(skb, 2);
 257                 memset(pos, 0, 2);
 258                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 259                         /* AID */
 260                         pos = skb_put(skb, 2);
 261                         memcpy(pos + 2, &plid, 2);
 262                 }
 263                 if (ieee80211_add_srates_ie(sdata, skb, true,
 264                                             local->oper_channel->band) ||
 265                     ieee80211_add_ext_srates_ie(sdata, skb, true,
 266                                                 local->oper_channel->band) ||
 267                     mesh_add_rsn_ie(skb, sdata) ||
 268                     mesh_add_meshid_ie(skb, sdata) ||
 269                     mesh_add_meshconf_ie(skb, sdata))
 270                         goto free;
 271         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 272                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
 273                 if (mesh_add_meshid_ie(skb, sdata))
 274                         goto free;
 275         }
 276
 277         /* Add Mesh Peering Management element */
 278         switch (action) {
 279         case WLAN_SP_MESH_PEERING_OPEN:
 280                 break;
 281         case WLAN_SP_MESH_PEERING_CONFIRM:
 282                 ie_len += 2;
 283                 include_plid = true;
 284                 break;
 285         case WLAN_SP_MESH_PEERING_CLOSE:
 286                 if (plid) {
 287                         ie_len += 2;
 288                         include_plid = true;
 289                 }
 290                 ie_len += 2;    /* reason code */
 291                 break;
 292         default:
 293                 err = -EINVAL;
 294                 goto free;
 295         }
 296
 297         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 298                 goto free;
 299
 300         pos = skb_put(skb, 2 + ie_len);
 301         *pos++ = WLAN_EID_PEER_MGMT;
 302         *pos++ = ie_len;
 303         memcpy(pos, &peering_proto, 2);
 304         pos += 2;
 305         memcpy(pos, &llid, 2);
 306         pos += 2;
 307         if (include_plid) {
 308                 memcpy(pos, &plid, 2);
 309                 pos += 2;
 310         }
 311         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 312                 memcpy(pos, &reason, 2);
 313                 pos += 2;
 314         }
 315
 316         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 317                 if (mesh_add_ht_cap_ie(skb, sdata) ||
 318                     mesh_add_ht_oper_ie(skb, sdata))
 319                         goto free;
 320         }
 321
 322         if (mesh_add_vendor_ies(skb, sdata))
 323                 goto free;
 324
 325         ieee80211_tx_skb(sdata, skb);
 326         return 0;
 327 free:
 328         kfree_skb(skb);
 329         return err;
 330 }
 331
 332 /**
 333  * mesh_peer_init - initialize new mesh peer and return resulting sta_info
 334  *
 335  * @sdata: local meshif
 336  * @addr: peer's address
 337  * @elems: IEs from beacon or mesh peering frame
 338  *
 339  * call under RCU
 340  */
 341 static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata,
 342                                        u8 *addr,
 343                                        struct ieee802_11_elems *elems)
 344 {
 345         struct ieee80211_local *local = sdata->local;
 346         enum ieee80211_band band = local->oper_channel->band;
 347         struct ieee80211_supported_band *sband;
 348         u32 rates, basic_rates = 0;
 349         struct sta_info *sta;
 350         bool insert = false;
 351
 352         sband = local->hw.wiphy->bands[band];
 353         rates = ieee80211_sta_get_rates(local, elems, band, &basic_rates);
 354
 355         sta = sta_info_get(sdata, addr);
 356         if (!sta) {
 357                 /* Userspace handles peer allocation when security is enabled */
 358                 if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
 359                         cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 360                                                            elems->ie_start,
 361                                                            elems->total_len,
 362                                                            GFP_ATOMIC);
 363                         return NULL;
 364                 }
 365
 366                 sta = mesh_plink_alloc(sdata, addr);
 367                 if (!sta)
 368                         return NULL;
 369                 insert = true;
 370         }
 371
 372         spin_lock_bh(&sta->lock);
 373         sta->last_rx = jiffies;
 374         if (sta->plink_state == NL80211_PLINK_ESTAB) {
 375                 spin_unlock_bh(&sta->lock);
 376                 return sta;
 377         }
 378
 379         sta->sta.supp_rates[band] = rates;
 380         if (elems->ht_cap_elem &&
 381             sdata->vif.bss_conf.channel_type != NL80211_CHAN_NO_HT)
 382                 ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 383                                                   elems->ht_cap_elem,
 384                                                   &sta->sta.ht_cap);
 385         else
 386                 memset(&sta->sta.ht_cap, 0, sizeof(sta->sta.ht_cap));
 387
 388         if (elems->ht_operation) {
 389                 if (!(elems->ht_operation->ht_param &
 390                       IEEE80211_HT_PARAM_CHAN_WIDTH_ANY))
 391                         sta->sta.ht_cap.cap &=
 392                                             ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 393                 sta->ch_type =
 394                         ieee80211_ht_oper_to_channel_type(elems->ht_operation);
 395         }
 396
 397         rate_control_rate_init(sta);
 398         spin_unlock_bh(&sta->lock);
 399
 400         if (insert && sta_info_insert(sta))
 401                 return NULL;
 402
 403         return sta;
 404 }
 405
 406 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 407                            u8 *hw_addr,
 408                            struct ieee802_11_elems *elems)
 409 {
 410         struct sta_info *sta;
 411
 412         rcu_read_lock();
 413         sta = mesh_peer_init(sdata, hw_addr, elems);
 414         if (!sta)
 415                 goto out;
 416
 417         if (mesh_peer_accepts_plinks(elems) &&
 418             sta->plink_state == NL80211_PLINK_LISTEN &&
 419             sdata->u.mesh.accepting_plinks &&
 420             sdata->u.mesh.mshcfg.auto_open_plinks &&
 421             rssi_threshold_check(sta, sdata))
 422                 mesh_plink_open(sta);
 423
 424 out:
 425         rcu_read_unlock();
 426 }
 427
 428 static void mesh_plink_timer(unsigned long data)
 429 {
 430         struct sta_info *sta;
 431         __le16 llid, plid, reason;
 432         struct ieee80211_sub_if_data *sdata;
 433
 434         /*
 435          * This STA is valid because sta_info_destroy() will
 436          * del_timer_sync() this timer after having made sure
 437          * it cannot be readded (by deleting the plink.)
 438          */
 439         sta = (struct sta_info *) data;
 440
 441         if (sta->sdata->local->quiescing) {
 442                 sta->plink_timer_was_running = true;
 443                 return;
 444         }
 445
 446         spin_lock_bh(&sta->lock);
 447         if (sta->ignore_plink_timer) {
 448                 sta->ignore_plink_timer = false;
 449                 spin_unlock_bh(&sta->lock);
 450                 return;
 451         }
 452         mpl_dbg(sta->sdata,
 453                 "Mesh plink timer for %pM fired on state %d\n",
 454                 sta->sta.addr, sta->plink_state);
 455         reason = 0;
 456         llid = sta->llid;
 457         plid = sta->plid;
 458         sdata = sta->sdata;
 459
 460         switch (sta->plink_state) {
 461         case NL80211_PLINK_OPN_RCVD:
 462         case NL80211_PLINK_OPN_SNT:
 463                 /* retry timer */
 464                 if (sta->plink_retries < dot11MeshMaxRetries(sdata)) {
 465                         u32 rand;
 466                         mpl_dbg(sta->sdata,
 467                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 468                                 sta->sta.addr, sta->plink_retries,
 469                                 sta->plink_timeout);
 470                         get_random_bytes(&rand, sizeof(u32));
 471                         sta->plink_timeout = sta->plink_timeout +
 472                                              rand % sta->plink_timeout;
 473                         ++sta->plink_retries;
 474                         mod_plink_timer(sta, sta->plink_timeout);
 475                         spin_unlock_bh(&sta->lock);
 476                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 477                                             sta->sta.addr, llid, 0, 0);
 478                         break;
 479                 }
 480                 reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);
 481                 /* fall through on else */
 482         case NL80211_PLINK_CNF_RCVD:
 483                 /* confirm timer */
 484                 if (!reason)
 485                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);
 486                 sta->plink_state = NL80211_PLINK_HOLDING;
 487                 mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 488                 spin_unlock_bh(&sta->lock);
 489                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 490                                     sta->sta.addr, llid, plid, reason);
 491                 break;
 492         case NL80211_PLINK_HOLDING:
 493                 /* holding timer */
 494                 del_timer(&sta->plink_timer);
 495                 mesh_plink_fsm_restart(sta);
 496                 spin_unlock_bh(&sta->lock);
 497                 break;
 498         default:
 499                 spin_unlock_bh(&sta->lock);
 500                 break;
 501         }
 502 }
 503
 504 #ifdef CONFIG_PM
 505 void mesh_plink_quiesce(struct sta_info *sta)
 506 {
 507         if (del_timer_sync(&sta->plink_timer))
 508                 sta->plink_timer_was_running = true;
 509 }
 510
 511 void mesh_plink_restart(struct sta_info *sta)
 512 {
 513         if (sta->plink_timer_was_running) {
 514                 add_timer(&sta->plink_timer);
 515                 sta->plink_timer_was_running = false;
 516         }
 517 }
 518 #endif
 519
 520 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 521 {
 522         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 523         sta->plink_timer.data = (unsigned long) sta;
 524         sta->plink_timer.function = mesh_plink_timer;
 525         sta->plink_timeout = timeout;
 526         add_timer(&sta->plink_timer);
 527 }
 528
 529 int mesh_plink_open(struct sta_info *sta)
 530 {
 531         __le16 llid;
 532         struct ieee80211_sub_if_data *sdata = sta->sdata;
 533
 534         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 535                 return -EPERM;
 536
 537         spin_lock_bh(&sta->lock);
 538         get_random_bytes(&llid, 2);
 539         sta->llid = llid;
 540         if (sta->plink_state != NL80211_PLINK_LISTEN) {
 541                 spin_unlock_bh(&sta->lock);
 542                 return -EBUSY;
 543         }
 544         sta->plink_state = NL80211_PLINK_OPN_SNT;
 545         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 546         spin_unlock_bh(&sta->lock);
 547         mpl_dbg(sdata,
 548                 "Mesh plink: starting establishment with %pM\n",
 549                 sta->sta.addr);
 550
 551         return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 552                                    sta->sta.addr, llid, 0, 0);
 553 }
 554
 555 void mesh_plink_block(struct sta_info *sta)
 556 {
 557         struct ieee80211_sub_if_data *sdata = sta->sdata;
 558         u32 changed;
 559
 560         spin_lock_bh(&sta->lock);
 561         changed = __mesh_plink_deactivate(sta);
 562         sta->plink_state = NL80211_PLINK_BLOCKED;
 563         spin_unlock_bh(&sta->lock);
 564
 565         ieee80211_bss_info_change_notify(sdata, changed);
 566 }
 567
 568
 569 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,
 570                          size_t len, struct ieee80211_rx_status *rx_status)
 571 {
 572         struct ieee802_11_elems elems;
 573         struct sta_info *sta;
 574         enum plink_event event;
 575         enum ieee80211_self_protected_actioncode ftype;
 576         size_t baselen;
 577         bool matches_local = true;
 578         u8 ie_len;
 579         u8 *baseaddr;
 580         u32 changed = 0;
 581         __le16 plid, llid, reason;
 582         static const char *mplstates[] = {
 583                 [NL80211_PLINK_LISTEN] = "LISTEN",
 584                 [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 585                 [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 586                 [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 587                 [NL80211_PLINK_ESTAB] = "ESTAB",
 588                 [NL80211_PLINK_HOLDING] = "HOLDING",
 589                 [NL80211_PLINK_BLOCKED] = "BLOCKED"
 590         };
 591
 592         /* need action_code, aux */
 593         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
 594                 return;
 595
 596         if (is_multicast_ether_addr(mgmt->da)) {
 597                 mpl_dbg(sdata,
 598                         "Mesh plink: ignore frame from multicast address\n");
 599                 return;
 600         }
 601
 602         baseaddr = mgmt->u.action.u.self_prot.variable;
 603         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
 604         if (mgmt->u.action.u.self_prot.action_code ==
 605                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
 606                 baseaddr += 4;
 607                 baselen += 4;
 608         }
 609         ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
 610         if (!elems.peering) {
 611                 mpl_dbg(sdata,
 612                         "Mesh plink: missing necessary peer link ie\n");
 613                 return;
 614         }
 615         if (elems.rsn_len &&
 616                         sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
 617                 mpl_dbg(sdata,
 618                         "Mesh plink: can't establish link with secure peer\n");
 619                 return;
 620         }
 621
 622         ftype = mgmt->u.action.u.self_prot.action_code;
 623         ie_len = elems.peering_len;
 624         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
 625             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
 626             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
 627                                                         && ie_len != 8)) {
 628                 mpl_dbg(sdata,
 629                         "Mesh plink: incorrect plink ie length %d %d\n",
 630                         ftype, ie_len);
 631                 return;
 632         }
 633
 634         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 635                                 (!elems.mesh_id || !elems.mesh_config)) {
 636                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
 637                 return;
 638         }
 639         /* Note the lines below are correct, the llid in the frame is the plid
 640          * from the point of view of this host.
 641          */
 642         memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
 643         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
 644             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
 645                 memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
 646
 647         rcu_read_lock();
 648
 649         sta = sta_info_get(sdata, mgmt->sa);
 650         if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
 651                 mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 652                 rcu_read_unlock();
 653                 return;
 654         }
 655
 656         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
 657             !rssi_threshold_check(sta, sdata)) {
 658                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
 659                         mgmt->sa);
 660                 rcu_read_unlock();
 661                 return;
 662         }
 663
 664         if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
 665                 mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 666                 rcu_read_unlock();
 667                 return;
 668         }
 669
 670         if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
 671                 rcu_read_unlock();
 672                 return;
 673         }
 674
 675         /* Now we will figure out the appropriate event... */
 676         event = PLINK_UNDEFINED;
 677         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 678             !mesh_matches_local(sdata, &elems)) {
 679                 matches_local = false;
 680                 switch (ftype) {
 681                 case WLAN_SP_MESH_PEERING_OPEN:
 682                         event = OPN_RJCT;
 683                         break;
 684                 case WLAN_SP_MESH_PEERING_CONFIRM:
 685                         event = CNF_RJCT;
 686                         break;
 687                 default:
 688                         break;
 689                 }
 690         }
 691
 692         if (!sta && !matches_local) {
 693                 rcu_read_unlock();
 694                 reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 695                 llid = 0;
 696                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 697                                     mgmt->sa, llid, plid, reason);
 698                 return;
 699         } else if (!sta) {
 700                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 701                 if (!mesh_plink_free_count(sdata)) {
 702                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 703                         rcu_read_unlock();
 704                         return;
 705                 }
 706                 event = OPN_ACPT;
 707         } else if (matches_local) {
 708                 switch (ftype) {
 709                 case WLAN_SP_MESH_PEERING_OPEN:
 710                         if (!mesh_plink_free_count(sdata) ||
 711                             (sta->plid && sta->plid != plid))
 712                                 event = OPN_IGNR;
 713                         else
 714                                 event = OPN_ACPT;
 715                         break;
 716                 case WLAN_SP_MESH_PEERING_CONFIRM:
 717                         if (!mesh_plink_free_count(sdata) ||
 718                             (sta->llid != llid || sta->plid != plid))
 719                                 event = CNF_IGNR;
 720                         else
 721                                 event = CNF_ACPT;
 722                         break;
 723                 case WLAN_SP_MESH_PEERING_CLOSE:
 724                         if (sta->plink_state == NL80211_PLINK_ESTAB)
 725                                 /* Do not check for llid or plid. This does not
 726                                  * follow the standard but since multiple plinks
 727                                  * per sta are not supported, it is necessary in
 728                                  * order to avoid a livelock when MP A sees an
 729                                  * establish peer link to MP B but MP B does not
 730                                  * see it. This can be caused by a timeout in
 731                                  * B's peer link establishment or B beign
 732                                  * restarted.
 733                                  */
 734                                 event = CLS_ACPT;
 735                         else if (sta->plid != plid)
 736                                 event = CLS_IGNR;
 737                         else if (ie_len == 7 && sta->llid != llid)
 738                                 event = CLS_IGNR;
 739                         else
 740                                 event = CLS_ACPT;
 741                         break;
 742                 default:
 743                         mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 744                         rcu_read_unlock();
 745                         return;
 746                 }
 747         }
 748
 749         if (event == OPN_ACPT) {
 750                 /* allocate sta entry if necessary and update info */
 751                 sta = mesh_peer_init(sdata, mgmt->sa, &elems);
 752                 if (!sta) {
 753                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
 754                         rcu_read_unlock();
 755                         return;
 756                 }
 757         }
 758
 759         mpl_dbg(sdata,
 760                 "Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
 761                 mgmt->sa, mplstates[sta->plink_state],
 762                 le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
 763                 event);
 764         reason = 0;
 765         spin_lock_bh(&sta->lock);
 766         switch (sta->plink_state) {
 767                 /* spin_unlock as soon as state is updated at each case */
 768         case NL80211_PLINK_LISTEN:
 769                 switch (event) {
 770                 case CLS_ACPT:
 771                         mesh_plink_fsm_restart(sta);
 772                         spin_unlock_bh(&sta->lock);
 773                         break;
 774                 case OPN_ACPT:
 775                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 776                         sta->plid = plid;
 777                         get_random_bytes(&llid, 2);
 778                         sta->llid = llid;
 779                         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 780                         spin_unlock_bh(&sta->lock);
 781                         mesh_plink_frame_tx(sdata,
 782                                             WLAN_SP_MESH_PEERING_OPEN,
 783                                             sta->sta.addr, llid, 0, 0);
 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_OPN_SNT:
 795                 switch (event) {
 796                 case OPN_RJCT:
 797                 case CNF_RJCT:
 798                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 799                 case CLS_ACPT:
 800                         if (!reason)
 801                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 802                         sta->reason = reason;
 803                         sta->plink_state = NL80211_PLINK_HOLDING;
 804                         if (!mod_plink_timer(sta,
 805                                              dot11MeshHoldingTimeout(sdata)))
 806                                 sta->ignore_plink_timer = true;
 807
 808                         llid = sta->llid;
 809                         spin_unlock_bh(&sta->lock);
 810                         mesh_plink_frame_tx(sdata,
 811                                             WLAN_SP_MESH_PEERING_CLOSE,
 812                                             sta->sta.addr, llid, plid, reason);
 813                         break;
 814                 case OPN_ACPT:
 815                         /* retry timer is left untouched */
 816                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 817                         sta->plid = plid;
 818                         llid = sta->llid;
 819                         spin_unlock_bh(&sta->lock);
 820                         mesh_plink_frame_tx(sdata,
 821                                             WLAN_SP_MESH_PEERING_CONFIRM,
 822                                             sta->sta.addr, llid, plid, 0);
 823                         break;
 824                 case CNF_ACPT:
 825                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 826                         if (!mod_plink_timer(sta,
 827                                              dot11MeshConfirmTimeout(sdata)))
 828                                 sta->ignore_plink_timer = true;
 829
 830                         spin_unlock_bh(&sta->lock);
 831                         break;
 832                 default:
 833                         spin_unlock_bh(&sta->lock);
 834                         break;
 835                 }
 836                 break;
 837
 838         case NL80211_PLINK_OPN_RCVD:
 839                 switch (event) {
 840                 case OPN_RJCT:
 841                 case CNF_RJCT:
 842                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 843                 case CLS_ACPT:
 844                         if (!reason)
 845                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 846                         sta->reason = reason;
 847                         sta->plink_state = NL80211_PLINK_HOLDING;
 848                         if (!mod_plink_timer(sta,
 849                                              dot11MeshHoldingTimeout(sdata)))
 850                                 sta->ignore_plink_timer = true;
 851
 852                         llid = sta->llid;
 853                         spin_unlock_bh(&sta->lock);
 854                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 855                                             sta->sta.addr, llid, plid, reason);
 856                         break;
 857                 case OPN_ACPT:
 858                         llid = sta->llid;
 859                         spin_unlock_bh(&sta->lock);
 860                         mesh_plink_frame_tx(sdata,
 861                                             WLAN_SP_MESH_PEERING_CONFIRM,
 862                                             sta->sta.addr, llid, plid, 0);
 863                         break;
 864                 case CNF_ACPT:
 865                         del_timer(&sta->plink_timer);
 866                         sta->plink_state = NL80211_PLINK_ESTAB;
 867                         spin_unlock_bh(&sta->lock);
 868                         changed |= mesh_plink_inc_estab_count(sdata);
 869                         changed |= mesh_set_ht_prot_mode(sdata);
 870                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 871                                 sta->sta.addr);
 872                         break;
 873                 default:
 874                         spin_unlock_bh(&sta->lock);
 875                         break;
 876                 }
 877                 break;
 878
 879         case NL80211_PLINK_CNF_RCVD:
 880                 switch (event) {
 881                 case OPN_RJCT:
 882                 case CNF_RJCT:
 883                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 884                 case CLS_ACPT:
 885                         if (!reason)
 886                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 887                         sta->reason = reason;
 888                         sta->plink_state = NL80211_PLINK_HOLDING;
 889                         if (!mod_plink_timer(sta,
 890                                              dot11MeshHoldingTimeout(sdata)))
 891                                 sta->ignore_plink_timer = true;
 892
 893                         llid = sta->llid;
 894                         spin_unlock_bh(&sta->lock);
 895                         mesh_plink_frame_tx(sdata,
 896                                             WLAN_SP_MESH_PEERING_CLOSE,
 897                                             sta->sta.addr, llid, plid, reason);
 898                         break;
 899                 case OPN_ACPT:
 900                         del_timer(&sta->plink_timer);
 901                         sta->plink_state = NL80211_PLINK_ESTAB;
 902                         spin_unlock_bh(&sta->lock);
 903                         changed |= mesh_plink_inc_estab_count(sdata);
 904                         changed |= mesh_set_ht_prot_mode(sdata);
 905                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 906                                 sta->sta.addr);
 907                         mesh_plink_frame_tx(sdata,
 908                                             WLAN_SP_MESH_PEERING_CONFIRM,
 909                                             sta->sta.addr, llid, plid, 0);
 910                         break;
 911                 default:
 912                         spin_unlock_bh(&sta->lock);
 913                         break;
 914                 }
 915                 break;
 916
 917         case NL80211_PLINK_ESTAB:
 918                 switch (event) {
 919                 case CLS_ACPT:
 920                         reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 921                         sta->reason = reason;
 922                         changed |= __mesh_plink_deactivate(sta);
 923                         sta->plink_state = NL80211_PLINK_HOLDING;
 924                         llid = sta->llid;
 925                         mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 926                         spin_unlock_bh(&sta->lock);
 927                         changed |= mesh_set_ht_prot_mode(sdata);
 928                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 929                                             sta->sta.addr, llid, plid, reason);
 930                         break;
 931                 case OPN_ACPT:
 932                         llid = sta->llid;
 933                         spin_unlock_bh(&sta->lock);
 934                         mesh_plink_frame_tx(sdata,
 935                                             WLAN_SP_MESH_PEERING_CONFIRM,
 936                                             sta->sta.addr, llid, plid, 0);
 937                         break;
 938                 default:
 939                         spin_unlock_bh(&sta->lock);
 940                         break;
 941                 }
 942                 break;
 943         case NL80211_PLINK_HOLDING:
 944                 switch (event) {
 945                 case CLS_ACPT:
 946                         if (del_timer(&sta->plink_timer))
 947                                 sta->ignore_plink_timer = 1;
 948                         mesh_plink_fsm_restart(sta);
 949                         spin_unlock_bh(&sta->lock);
 950                         break;
 951                 case OPN_ACPT:
 952                 case CNF_ACPT:
 953                 case OPN_RJCT:
 954                 case CNF_RJCT:
 955                         llid = sta->llid;
 956                         reason = sta->reason;
 957                         spin_unlock_bh(&sta->lock);
 958                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 959                                             sta->sta.addr, llid, plid, reason);
 960                         break;
 961                 default:
 962                         spin_unlock_bh(&sta->lock);
 963                 }
 964                 break;
 965         default:
 966                 /* should not get here, PLINK_BLOCKED is dealt with at the
 967                  * beginning of the function
 968                  */
 969                 spin_unlock_bh(&sta->lock);
 970                 break;
 971         }
 972
 973         rcu_read_unlock();
 974
 975         if (changed)
 976                 ieee80211_bss_info_change_notify(sdata, changed);
 977 }