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 /* We only need a valid sta if user configured a minimum rssi_threshold. */
  23 #define rssi_threshold_check(sta, sdata) \
  24                 (sdata->u.mesh.mshcfg.rssi_threshold == 0 ||\
  25                 (sta && (s8) -ewma_read(&sta->avg_signal) > \
  26                 sdata->u.mesh.mshcfg.rssi_threshold))
  27
  28 enum plink_event {
  29         PLINK_UNDEFINED,
  30         OPN_ACPT,
  31         OPN_RJCT,
  32         OPN_IGNR,
  33         CNF_ACPT,
  34         CNF_RJCT,
  35         CNF_IGNR,
  36         CLS_ACPT,
  37         CLS_IGNR
  38 };
  39
  40 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
  41                 enum ieee80211_self_protected_actioncode action,
  42                 u8 *da, __le16 llid, __le16 plid, __le16 reason);
  43
  44 static inline
  45 u32 mesh_plink_inc_estab_count(struct ieee80211_sub_if_data *sdata)
  46 {
  47         atomic_inc(&sdata->u.mesh.estab_plinks);
  48         return mesh_accept_plinks_update(sdata);
  49 }
  50
  51 static inline
  52 u32 mesh_plink_dec_estab_count(struct ieee80211_sub_if_data *sdata)
  53 {
  54         atomic_dec(&sdata->u.mesh.estab_plinks);
  55         return mesh_accept_plinks_update(sdata);
  56 }
  57
  58 /**
  59  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  60  *
  61  * @sta: mesh peer link to restart
  62  *
  63  * Locking: this function must be called holding sta->lock
  64  */
  65 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  66 {
  67         sta->plink_state = NL80211_PLINK_LISTEN;
  68         sta->llid = sta->plid = sta->reason = 0;
  69         sta->plink_retries = 0;
  70 }
  71
  72 /*
  73  * Allocate mesh sta entry and insert into station table
  74  */
  75 static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
  76                                          u8 *hw_addr)
  77 {
  78         struct sta_info *sta;
  79
  80         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
  81                 return NULL;
  82
  83         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
  84         if (!sta)
  85                 return NULL;
  86
  87         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
  88         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
  89         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
  90
  91         set_sta_flag(sta, WLAN_STA_WME);
  92
  93         return sta;
  94 }
  95
  96 /**
  97  * mesh_set_ht_prot_mode - set correct HT protection mode
  98  *
  99  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 100  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 101  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 102  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 103  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 104  * HT20 peer is present. Otherwise no-protection mode is selected.
 105  */
 106 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 107 {
 108         struct ieee80211_local *local = sdata->local;
 109         struct sta_info *sta;
 110         u32 changed = 0;
 111         u16 ht_opmode;
 112         bool non_ht_sta = false, ht20_sta = false;
 113
 114         if (sdata->vif.bss_conf.chandef.width == NL80211_CHAN_WIDTH_20_NOHT)
 115                 return 0;
 116
 117         rcu_read_lock();
 118         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 119                 if (sdata != sta->sdata ||
 120                     sta->plink_state != NL80211_PLINK_ESTAB)
 121                         continue;
 122
 123                 switch (sta->ch_width) {
 124                 case NL80211_CHAN_WIDTH_20_NOHT:
 125                         mpl_dbg(sdata,
 126                                 "mesh_plink %pM: nonHT sta (%pM) is present\n",
 127                                 sdata->vif.addr, sta->sta.addr);
 128                         non_ht_sta = true;
 129                         goto out;
 130                 case NL80211_CHAN_WIDTH_20:
 131                         mpl_dbg(sdata,
 132                                 "mesh_plink %pM: HT20 sta (%pM) is present\n",
 133                                 sdata->vif.addr, sta->sta.addr);
 134                         ht20_sta = true;
 135                 default:
 136                         break;
 137                 }
 138         }
 139 out:
 140         rcu_read_unlock();
 141
 142         if (non_ht_sta)
 143                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 144         else if (ht20_sta &&
 145                  sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
 146                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 147         else
 148                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 149
 150         if (sdata->vif.bss_conf.ht_operation_mode != ht_opmode) {
 151                 sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 152                 sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 153                 changed = BSS_CHANGED_HT;
 154                 mpl_dbg(sdata,
 155                         "mesh_plink %pM: protection mode changed to %d\n",
 156                         sdata->vif.addr, ht_opmode);
 157         }
 158
 159         return changed;
 160 }
 161
 162 /**
 163  * __mesh_plink_deactivate - deactivate mesh peer link
 164  *
 165  * @sta: mesh peer link to deactivate
 166  *
 167  * All mesh paths with this peer as next hop will be flushed
 168  * Returns beacon changed flag if the beacon content changed.
 169  *
 170  * Locking: the caller must hold sta->lock
 171  */
 172 static u32 __mesh_plink_deactivate(struct sta_info *sta)
 173 {
 174         struct ieee80211_sub_if_data *sdata = sta->sdata;
 175         u32 changed = 0;
 176
 177         if (sta->plink_state == NL80211_PLINK_ESTAB)
 178                 changed = mesh_plink_dec_estab_count(sdata);
 179         sta->plink_state = NL80211_PLINK_BLOCKED;
 180         mesh_path_flush_by_nexthop(sta);
 181
 182         return changed;
 183 }
 184
 185 /**
 186  * mesh_plink_deactivate - deactivate mesh peer link
 187  *
 188  * @sta: mesh peer link to deactivate
 189  *
 190  * All mesh paths with this peer as next hop will be flushed
 191  */
 192 void mesh_plink_deactivate(struct sta_info *sta)
 193 {
 194         struct ieee80211_sub_if_data *sdata = sta->sdata;
 195         u32 changed;
 196
 197         spin_lock_bh(&sta->lock);
 198         changed = __mesh_plink_deactivate(sta);
 199         sta->reason = cpu_to_le16(WLAN_REASON_MESH_PEER_CANCELED);
 200         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 201                             sta->sta.addr, sta->llid, sta->plid,
 202                             sta->reason);
 203         spin_unlock_bh(&sta->lock);
 204
 205         ieee80211_bss_info_change_notify(sdata, changed);
 206 }
 207
 208 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 209                 enum ieee80211_self_protected_actioncode action,
 210                 u8 *da, __le16 llid, __le16 plid, __le16 reason) {
 211         struct ieee80211_local *local = sdata->local;
 212         struct sk_buff *skb;
 213         struct ieee80211_tx_info *info;
 214         struct ieee80211_mgmt *mgmt;
 215         bool include_plid = false;
 216         u16 peering_proto = 0;
 217         u8 *pos, ie_len = 4;
 218         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 219                       sizeof(mgmt->u.action.u.self_prot);
 220         int err = -ENOMEM;
 221
 222         skb = dev_alloc_skb(local->tx_headroom +
 223                             hdr_len +
 224                             2 + /* capability info */
 225                             2 + /* AID */
 226                             2 + 8 + /* supported rates */
 227                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 228                             2 + sdata->u.mesh.mesh_id_len +
 229                             2 + sizeof(struct ieee80211_meshconf_ie) +
 230                             2 + sizeof(struct ieee80211_ht_cap) +
 231                             2 + sizeof(struct ieee80211_ht_operation) +
 232                             2 + 8 + /* peering IE */
 233                             sdata->u.mesh.ie_len);
 234         if (!skb)
 235                 return -1;
 236         info = IEEE80211_SKB_CB(skb);
 237         skb_reserve(skb, local->tx_headroom);
 238         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 239         memset(mgmt, 0, hdr_len);
 240         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 241                                           IEEE80211_STYPE_ACTION);
 242         memcpy(mgmt->da, da, ETH_ALEN);
 243         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 244         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 245         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 246         mgmt->u.action.u.self_prot.action_code = action;
 247
 248         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 249                 enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 250
 251                 /* capability info */
 252                 pos = skb_put(skb, 2);
 253                 memset(pos, 0, 2);
 254                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 255                         /* AID */
 256                         pos = skb_put(skb, 2);
 257                         memcpy(pos + 2, &plid, 2);
 258                 }
 259                 if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
 260                     ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
 261                     mesh_add_rsn_ie(skb, sdata) ||
 262                     mesh_add_meshid_ie(skb, sdata) ||
 263                     mesh_add_meshconf_ie(skb, sdata))
 264                         goto free;
 265         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 266                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
 267                 if (mesh_add_meshid_ie(skb, sdata))
 268                         goto free;
 269         }
 270
 271         /* Add Mesh Peering Management element */
 272         switch (action) {
 273         case WLAN_SP_MESH_PEERING_OPEN:
 274                 break;
 275         case WLAN_SP_MESH_PEERING_CONFIRM:
 276                 ie_len += 2;
 277                 include_plid = true;
 278                 break;
 279         case WLAN_SP_MESH_PEERING_CLOSE:
 280                 if (plid) {
 281                         ie_len += 2;
 282                         include_plid = true;
 283                 }
 284                 ie_len += 2;    /* reason code */
 285                 break;
 286         default:
 287                 err = -EINVAL;
 288                 goto free;
 289         }
 290
 291         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 292                 goto free;
 293
 294         pos = skb_put(skb, 2 + ie_len);
 295         *pos++ = WLAN_EID_PEER_MGMT;
 296         *pos++ = ie_len;
 297         memcpy(pos, &peering_proto, 2);
 298         pos += 2;
 299         memcpy(pos, &llid, 2);
 300         pos += 2;
 301         if (include_plid) {
 302                 memcpy(pos, &plid, 2);
 303                 pos += 2;
 304         }
 305         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 306                 memcpy(pos, &reason, 2);
 307                 pos += 2;
 308         }
 309
 310         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 311                 if (mesh_add_ht_cap_ie(skb, sdata) ||
 312                     mesh_add_ht_oper_ie(skb, sdata))
 313                         goto free;
 314         }
 315
 316         if (mesh_add_vendor_ies(skb, sdata))
 317                 goto free;
 318
 319         ieee80211_tx_skb(sdata, skb);
 320         return 0;
 321 free:
 322         kfree_skb(skb);
 323         return err;
 324 }
 325
 326 /**
 327  * mesh_peer_init - initialize new mesh peer and return resulting sta_info
 328  *
 329  * @sdata: local meshif
 330  * @addr: peer's address
 331  * @elems: IEs from beacon or mesh peering frame
 332  *
 333  * call under RCU
 334  */
 335 static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata,
 336                                        u8 *addr,
 337                                        struct ieee802_11_elems *elems)
 338 {
 339         struct ieee80211_local *local = sdata->local;
 340         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 341         struct ieee80211_supported_band *sband;
 342         u32 rates, basic_rates = 0;
 343         struct sta_info *sta;
 344         bool insert = false;
 345
 346         sband = local->hw.wiphy->bands[band];
 347         rates = ieee80211_sta_get_rates(local, elems, band, &basic_rates);
 348
 349         sta = sta_info_get(sdata, addr);
 350         if (!sta) {
 351                 /* Userspace handles peer allocation when security is enabled */
 352                 if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
 353                         cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 354                                                            elems->ie_start,
 355                                                            elems->total_len,
 356                                                            GFP_ATOMIC);
 357                         return NULL;
 358                 }
 359
 360                 sta = mesh_plink_alloc(sdata, addr);
 361                 if (!sta)
 362                         return NULL;
 363                 insert = true;
 364         }
 365
 366         spin_lock_bh(&sta->lock);
 367         sta->last_rx = jiffies;
 368         if (sta->plink_state == NL80211_PLINK_ESTAB) {
 369                 spin_unlock_bh(&sta->lock);
 370                 return sta;
 371         }
 372
 373         sta->sta.supp_rates[band] = rates;
 374         if (elems->ht_cap_elem &&
 375             sdata->vif.bss_conf.chandef.width != NL80211_CHAN_WIDTH_20_NOHT)
 376                 ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 377                                                   elems->ht_cap_elem,
 378                                                   &sta->sta.ht_cap);
 379         else
 380                 memset(&sta->sta.ht_cap, 0, sizeof(sta->sta.ht_cap));
 381
 382         if (elems->ht_operation) {
 383                 struct cfg80211_chan_def chandef;
 384
 385                 if (!(elems->ht_operation->ht_param &
 386                       IEEE80211_HT_PARAM_CHAN_WIDTH_ANY))
 387                         sta->sta.ht_cap.cap &=
 388                                             ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 389                 ieee80211_ht_oper_to_chandef(sdata->vif.bss_conf.chandef.chan,
 390                                              elems->ht_operation, &chandef);
 391                 sta->ch_width = chandef.width;
 392         }
 393
 394         if (insert)
 395                 rate_control_rate_init(sta);
 396         spin_unlock_bh(&sta->lock);
 397
 398         if (insert && sta_info_insert(sta))
 399                 return NULL;
 400
 401         return sta;
 402 }
 403
 404 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 405                            u8 *hw_addr,
 406                            struct ieee802_11_elems *elems)
 407 {
 408         struct sta_info *sta;
 409
 410         rcu_read_lock();
 411         sta = mesh_peer_init(sdata, hw_addr, elems);
 412         if (!sta)
 413                 goto out;
 414
 415         if (mesh_peer_accepts_plinks(elems) &&
 416             sta->plink_state == NL80211_PLINK_LISTEN &&
 417             sdata->u.mesh.accepting_plinks &&
 418             sdata->u.mesh.mshcfg.auto_open_plinks &&
 419             rssi_threshold_check(sta, sdata))
 420                 mesh_plink_open(sta);
 421
 422 out:
 423         rcu_read_unlock();
 424 }
 425
 426 static void mesh_plink_timer(unsigned long data)
 427 {
 428         struct sta_info *sta;
 429         __le16 llid, plid, reason;
 430         struct ieee80211_sub_if_data *sdata;
 431         struct mesh_config *mshcfg;
 432
 433         /*
 434          * This STA is valid because sta_info_destroy() will
 435          * del_timer_sync() this timer after having made sure
 436          * it cannot be readded (by deleting the plink.)
 437          */
 438         sta = (struct sta_info *) data;
 439
 440         if (sta->sdata->local->quiescing) {
 441                 sta->plink_timer_was_running = true;
 442                 return;
 443         }
 444
 445         spin_lock_bh(&sta->lock);
 446         if (sta->ignore_plink_timer) {
 447                 sta->ignore_plink_timer = false;
 448                 spin_unlock_bh(&sta->lock);
 449                 return;
 450         }
 451         mpl_dbg(sta->sdata,
 452                 "Mesh plink timer for %pM fired on state %d\n",
 453                 sta->sta.addr, sta->plink_state);
 454         reason = 0;
 455         llid = sta->llid;
 456         plid = sta->plid;
 457         sdata = sta->sdata;
 458         mshcfg = &sdata->u.mesh.mshcfg;
 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 < mshcfg->dot11MeshMaxRetries) {
 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, mshcfg->dot11MeshHoldingTimeout);
 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             sta->plink_state != NL80211_PLINK_BLOCKED) {
 542                 spin_unlock_bh(&sta->lock);
 543                 return -EBUSY;
 544         }
 545         sta->plink_state = NL80211_PLINK_OPN_SNT;
 546         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 547         spin_unlock_bh(&sta->lock);
 548         mpl_dbg(sdata,
 549                 "Mesh plink: starting establishment with %pM\n",
 550                 sta->sta.addr);
 551
 552         return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 553                                    sta->sta.addr, llid, 0, 0);
 554 }
 555
 556 void mesh_plink_block(struct sta_info *sta)
 557 {
 558         struct ieee80211_sub_if_data *sdata = sta->sdata;
 559         u32 changed;
 560
 561         spin_lock_bh(&sta->lock);
 562         changed = __mesh_plink_deactivate(sta);
 563         sta->plink_state = NL80211_PLINK_BLOCKED;
 564         spin_unlock_bh(&sta->lock);
 565
 566         ieee80211_bss_info_change_notify(sdata, changed);
 567 }
 568
 569
 570 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,
 571                          size_t len, struct ieee80211_rx_status *rx_status)
 572 {
 573         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 574         struct ieee802_11_elems elems;
 575         struct sta_info *sta;
 576         enum plink_event event;
 577         enum ieee80211_self_protected_actioncode ftype;
 578         size_t baselen;
 579         bool matches_local = true;
 580         u8 ie_len;
 581         u8 *baseaddr;
 582         u32 changed = 0;
 583         __le16 plid, llid, reason;
 584         static const char *mplstates[] = {
 585                 [NL80211_PLINK_LISTEN] = "LISTEN",
 586                 [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 587                 [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 588                 [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 589                 [NL80211_PLINK_ESTAB] = "ESTAB",
 590                 [NL80211_PLINK_HOLDING] = "HOLDING",
 591                 [NL80211_PLINK_BLOCKED] = "BLOCKED"
 592         };
 593
 594         /* need action_code, aux */
 595         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
 596                 return;
 597
 598         if (is_multicast_ether_addr(mgmt->da)) {
 599                 mpl_dbg(sdata,
 600                         "Mesh plink: ignore frame from multicast address\n");
 601                 return;
 602         }
 603
 604         baseaddr = mgmt->u.action.u.self_prot.variable;
 605         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
 606         if (mgmt->u.action.u.self_prot.action_code ==
 607                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
 608                 baseaddr += 4;
 609                 baselen += 4;
 610         }
 611         ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
 612         if (!elems.peering) {
 613                 mpl_dbg(sdata,
 614                         "Mesh plink: missing necessary peer link ie\n");
 615                 return;
 616         }
 617         if (elems.rsn_len &&
 618                         sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
 619                 mpl_dbg(sdata,
 620                         "Mesh plink: can't establish link with secure peer\n");
 621                 return;
 622         }
 623
 624         ftype = mgmt->u.action.u.self_prot.action_code;
 625         ie_len = elems.peering_len;
 626         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
 627             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
 628             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
 629                                                         && ie_len != 8)) {
 630                 mpl_dbg(sdata,
 631                         "Mesh plink: incorrect plink ie length %d %d\n",
 632                         ftype, ie_len);
 633                 return;
 634         }
 635
 636         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 637                                 (!elems.mesh_id || !elems.mesh_config)) {
 638                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
 639                 return;
 640         }
 641         /* Note the lines below are correct, the llid in the frame is the plid
 642          * from the point of view of this host.
 643          */
 644         memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
 645         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
 646             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
 647                 memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
 648
 649         rcu_read_lock();
 650
 651         sta = sta_info_get(sdata, mgmt->sa);
 652         if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
 653                 mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 654                 rcu_read_unlock();
 655                 return;
 656         }
 657
 658         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
 659             !rssi_threshold_check(sta, sdata)) {
 660                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
 661                         mgmt->sa);
 662                 rcu_read_unlock();
 663                 return;
 664         }
 665
 666         if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
 667                 mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 668                 rcu_read_unlock();
 669                 return;
 670         }
 671
 672         if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
 673                 rcu_read_unlock();
 674                 return;
 675         }
 676
 677         /* Now we will figure out the appropriate event... */
 678         event = PLINK_UNDEFINED;
 679         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 680             !mesh_matches_local(sdata, &elems)) {
 681                 matches_local = false;
 682                 switch (ftype) {
 683                 case WLAN_SP_MESH_PEERING_OPEN:
 684                         event = OPN_RJCT;
 685                         break;
 686                 case WLAN_SP_MESH_PEERING_CONFIRM:
 687                         event = CNF_RJCT;
 688                         break;
 689                 default:
 690                         break;
 691                 }
 692         }
 693
 694         if (!sta && !matches_local) {
 695                 rcu_read_unlock();
 696                 reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 697                 llid = 0;
 698                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 699                                     mgmt->sa, llid, plid, reason);
 700                 return;
 701         } else if (!sta) {
 702                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 703                 if (!mesh_plink_free_count(sdata)) {
 704                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 705                         rcu_read_unlock();
 706                         return;
 707                 }
 708                 event = OPN_ACPT;
 709         } else if (matches_local) {
 710                 switch (ftype) {
 711                 case WLAN_SP_MESH_PEERING_OPEN:
 712                         if (!mesh_plink_free_count(sdata) ||
 713                             (sta->plid && sta->plid != plid))
 714                                 event = OPN_IGNR;
 715                         else
 716                                 event = OPN_ACPT;
 717                         break;
 718                 case WLAN_SP_MESH_PEERING_CONFIRM:
 719                         if (!mesh_plink_free_count(sdata) ||
 720                             (sta->llid != llid || sta->plid != plid))
 721                                 event = CNF_IGNR;
 722                         else
 723                                 event = CNF_ACPT;
 724                         break;
 725                 case WLAN_SP_MESH_PEERING_CLOSE:
 726                         if (sta->plink_state == NL80211_PLINK_ESTAB)
 727                                 /* Do not check for llid or plid. This does not
 728                                  * follow the standard but since multiple plinks
 729                                  * per sta are not supported, it is necessary in
 730                                  * order to avoid a livelock when MP A sees an
 731                                  * establish peer link to MP B but MP B does not
 732                                  * see it. This can be caused by a timeout in
 733                                  * B's peer link establishment or B beign
 734                                  * restarted.
 735                                  */
 736                                 event = CLS_ACPT;
 737                         else if (sta->plid != plid)
 738                                 event = CLS_IGNR;
 739                         else if (ie_len == 7 && sta->llid != llid)
 740                                 event = CLS_IGNR;
 741                         else
 742                                 event = CLS_ACPT;
 743                         break;
 744                 default:
 745                         mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 746                         rcu_read_unlock();
 747                         return;
 748                 }
 749         }
 750
 751         if (event == OPN_ACPT) {
 752                 /* allocate sta entry if necessary and update info */
 753                 sta = mesh_peer_init(sdata, mgmt->sa, &elems);
 754                 if (!sta) {
 755                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
 756                         rcu_read_unlock();
 757                         return;
 758                 }
 759         }
 760
 761         mpl_dbg(sdata,
 762                 "Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
 763                 mgmt->sa, mplstates[sta->plink_state],
 764                 le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
 765                 event);
 766         reason = 0;
 767         spin_lock_bh(&sta->lock);
 768         switch (sta->plink_state) {
 769                 /* spin_unlock as soon as state is updated at each case */
 770         case NL80211_PLINK_LISTEN:
 771                 switch (event) {
 772                 case CLS_ACPT:
 773                         mesh_plink_fsm_restart(sta);
 774                         spin_unlock_bh(&sta->lock);
 775                         break;
 776                 case OPN_ACPT:
 777                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 778                         sta->plid = plid;
 779                         get_random_bytes(&llid, 2);
 780                         sta->llid = llid;
 781                         mesh_plink_timer_set(sta,
 782                                              mshcfg->dot11MeshRetryTimeout);
 783                         spin_unlock_bh(&sta->lock);
 784                         mesh_plink_frame_tx(sdata,
 785                                             WLAN_SP_MESH_PEERING_OPEN,
 786                                             sta->sta.addr, llid, 0, 0);
 787                         mesh_plink_frame_tx(sdata,
 788                                             WLAN_SP_MESH_PEERING_CONFIRM,
 789                                             sta->sta.addr, llid, plid, 0);
 790                         break;
 791                 default:
 792                         spin_unlock_bh(&sta->lock);
 793                         break;
 794                 }
 795                 break;
 796
 797         case NL80211_PLINK_OPN_SNT:
 798                 switch (event) {
 799                 case OPN_RJCT:
 800                 case CNF_RJCT:
 801                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 802                 case CLS_ACPT:
 803                         if (!reason)
 804                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 805                         sta->reason = reason;
 806                         sta->plink_state = NL80211_PLINK_HOLDING;
 807                         if (!mod_plink_timer(sta,
 808                                              mshcfg->dot11MeshHoldingTimeout))
 809                                 sta->ignore_plink_timer = true;
 810
 811                         llid = sta->llid;
 812                         spin_unlock_bh(&sta->lock);
 813                         mesh_plink_frame_tx(sdata,
 814                                             WLAN_SP_MESH_PEERING_CLOSE,
 815                                             sta->sta.addr, llid, plid, reason);
 816                         break;
 817                 case OPN_ACPT:
 818                         /* retry timer is left untouched */
 819                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 820                         sta->plid = plid;
 821                         llid = sta->llid;
 822                         spin_unlock_bh(&sta->lock);
 823                         mesh_plink_frame_tx(sdata,
 824                                             WLAN_SP_MESH_PEERING_CONFIRM,
 825                                             sta->sta.addr, llid, plid, 0);
 826                         break;
 827                 case CNF_ACPT:
 828                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 829                         if (!mod_plink_timer(sta,
 830                                              mshcfg->dot11MeshConfirmTimeout))
 831                                 sta->ignore_plink_timer = true;
 832
 833                         spin_unlock_bh(&sta->lock);
 834                         break;
 835                 default:
 836                         spin_unlock_bh(&sta->lock);
 837                         break;
 838                 }
 839                 break;
 840
 841         case NL80211_PLINK_OPN_RCVD:
 842                 switch (event) {
 843                 case OPN_RJCT:
 844                 case CNF_RJCT:
 845                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 846                 case CLS_ACPT:
 847                         if (!reason)
 848                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 849                         sta->reason = reason;
 850                         sta->plink_state = NL80211_PLINK_HOLDING;
 851                         if (!mod_plink_timer(sta,
 852                                              mshcfg->dot11MeshHoldingTimeout))
 853                                 sta->ignore_plink_timer = true;
 854
 855                         llid = sta->llid;
 856                         spin_unlock_bh(&sta->lock);
 857                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 858                                             sta->sta.addr, llid, plid, reason);
 859                         break;
 860                 case OPN_ACPT:
 861                         llid = sta->llid;
 862                         spin_unlock_bh(&sta->lock);
 863                         mesh_plink_frame_tx(sdata,
 864                                             WLAN_SP_MESH_PEERING_CONFIRM,
 865                                             sta->sta.addr, llid, plid, 0);
 866                         break;
 867                 case CNF_ACPT:
 868                         del_timer(&sta->plink_timer);
 869                         sta->plink_state = NL80211_PLINK_ESTAB;
 870                         spin_unlock_bh(&sta->lock);
 871                         changed |= mesh_plink_inc_estab_count(sdata);
 872                         changed |= mesh_set_ht_prot_mode(sdata);
 873                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 874                                 sta->sta.addr);
 875                         break;
 876                 default:
 877                         spin_unlock_bh(&sta->lock);
 878                         break;
 879                 }
 880                 break;
 881
 882         case NL80211_PLINK_CNF_RCVD:
 883                 switch (event) {
 884                 case OPN_RJCT:
 885                 case CNF_RJCT:
 886                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 887                 case CLS_ACPT:
 888                         if (!reason)
 889                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 890                         sta->reason = reason;
 891                         sta->plink_state = NL80211_PLINK_HOLDING;
 892                         if (!mod_plink_timer(sta,
 893                                              mshcfg->dot11MeshHoldingTimeout))
 894                                 sta->ignore_plink_timer = true;
 895
 896                         llid = sta->llid;
 897                         spin_unlock_bh(&sta->lock);
 898                         mesh_plink_frame_tx(sdata,
 899                                             WLAN_SP_MESH_PEERING_CLOSE,
 900                                             sta->sta.addr, llid, plid, reason);
 901                         break;
 902                 case OPN_ACPT:
 903                         del_timer(&sta->plink_timer);
 904                         sta->plink_state = NL80211_PLINK_ESTAB;
 905                         spin_unlock_bh(&sta->lock);
 906                         changed |= mesh_plink_inc_estab_count(sdata);
 907                         changed |= mesh_set_ht_prot_mode(sdata);
 908                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 909                                 sta->sta.addr);
 910                         mesh_plink_frame_tx(sdata,
 911                                             WLAN_SP_MESH_PEERING_CONFIRM,
 912                                             sta->sta.addr, llid, plid, 0);
 913                         break;
 914                 default:
 915                         spin_unlock_bh(&sta->lock);
 916                         break;
 917                 }
 918                 break;
 919
 920         case NL80211_PLINK_ESTAB:
 921                 switch (event) {
 922                 case CLS_ACPT:
 923                         reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 924                         sta->reason = reason;
 925                         changed |= __mesh_plink_deactivate(sta);
 926                         sta->plink_state = NL80211_PLINK_HOLDING;
 927                         llid = sta->llid;
 928                         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 929                         spin_unlock_bh(&sta->lock);
 930                         changed |= mesh_set_ht_prot_mode(sdata);
 931                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 932                                             sta->sta.addr, llid, plid, reason);
 933                         break;
 934                 case OPN_ACPT:
 935                         llid = sta->llid;
 936                         spin_unlock_bh(&sta->lock);
 937                         mesh_plink_frame_tx(sdata,
 938                                             WLAN_SP_MESH_PEERING_CONFIRM,
 939                                             sta->sta.addr, llid, plid, 0);
 940                         break;
 941                 default:
 942                         spin_unlock_bh(&sta->lock);
 943                         break;
 944                 }
 945                 break;
 946         case NL80211_PLINK_HOLDING:
 947                 switch (event) {
 948                 case CLS_ACPT:
 949                         if (del_timer(&sta->plink_timer))
 950                                 sta->ignore_plink_timer = 1;
 951                         mesh_plink_fsm_restart(sta);
 952                         spin_unlock_bh(&sta->lock);
 953                         break;
 954                 case OPN_ACPT:
 955                 case CNF_ACPT:
 956                 case OPN_RJCT:
 957                 case CNF_RJCT:
 958                         llid = sta->llid;
 959                         reason = sta->reason;
 960                         spin_unlock_bh(&sta->lock);
 961                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 962                                             sta->sta.addr, llid, plid, reason);
 963                         break;
 964                 default:
 965                         spin_unlock_bh(&sta->lock);
 966                 }
 967                 break;
 968         default:
 969                 /* should not get here, PLINK_BLOCKED is dealt with at the
 970                  * beginning of the function
 971                  */
 972                 spin_unlock_bh(&sta->lock);
 973                 break;
 974         }
 975
 976         rcu_read_unlock();
 977
 978         if (changed)
 979                 ieee80211_bss_info_change_notify(sdata, changed);
 980 }