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         rate_control_rate_init(sta);
 395         spin_unlock_bh(&sta->lock);
 396
 397         if (insert && sta_info_insert(sta))
 398                 return NULL;
 399
 400         return sta;
 401 }
 402
 403 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 404                            u8 *hw_addr,
 405                            struct ieee802_11_elems *elems)
 406 {
 407         struct sta_info *sta;
 408
 409         rcu_read_lock();
 410         sta = mesh_peer_init(sdata, hw_addr, elems);
 411         if (!sta)
 412                 goto out;
 413
 414         if (mesh_peer_accepts_plinks(elems) &&
 415             sta->plink_state == NL80211_PLINK_LISTEN &&
 416             sdata->u.mesh.accepting_plinks &&
 417             sdata->u.mesh.mshcfg.auto_open_plinks &&
 418             rssi_threshold_check(sta, sdata))
 419                 mesh_plink_open(sta);
 420
 421 out:
 422         rcu_read_unlock();
 423 }
 424
 425 static void mesh_plink_timer(unsigned long data)
 426 {
 427         struct sta_info *sta;
 428         __le16 llid, plid, reason;
 429         struct ieee80211_sub_if_data *sdata;
 430         struct mesh_config *mshcfg;
 431
 432         /*
 433          * This STA is valid because sta_info_destroy() will
 434          * del_timer_sync() this timer after having made sure
 435          * it cannot be readded (by deleting the plink.)
 436          */
 437         sta = (struct sta_info *) data;
 438
 439         if (sta->sdata->local->quiescing) {
 440                 sta->plink_timer_was_running = true;
 441                 return;
 442         }
 443
 444         spin_lock_bh(&sta->lock);
 445         if (sta->ignore_plink_timer) {
 446                 sta->ignore_plink_timer = false;
 447                 spin_unlock_bh(&sta->lock);
 448                 return;
 449         }
 450         mpl_dbg(sta->sdata,
 451                 "Mesh plink timer for %pM fired on state %d\n",
 452                 sta->sta.addr, sta->plink_state);
 453         reason = 0;
 454         llid = sta->llid;
 455         plid = sta->plid;
 456         sdata = sta->sdata;
 457         mshcfg = &sdata->u.mesh.mshcfg;
 458
 459         switch (sta->plink_state) {
 460         case NL80211_PLINK_OPN_RCVD:
 461         case NL80211_PLINK_OPN_SNT:
 462                 /* retry timer */
 463                 if (sta->plink_retries < mshcfg->dot11MeshMaxRetries) {
 464                         u32 rand;
 465                         mpl_dbg(sta->sdata,
 466                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 467                                 sta->sta.addr, sta->plink_retries,
 468                                 sta->plink_timeout);
 469                         get_random_bytes(&rand, sizeof(u32));
 470                         sta->plink_timeout = sta->plink_timeout +
 471                                              rand % sta->plink_timeout;
 472                         ++sta->plink_retries;
 473                         mod_plink_timer(sta, sta->plink_timeout);
 474                         spin_unlock_bh(&sta->lock);
 475                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 476                                             sta->sta.addr, llid, 0, 0);
 477                         break;
 478                 }
 479                 reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);
 480                 /* fall through on else */
 481         case NL80211_PLINK_CNF_RCVD:
 482                 /* confirm timer */
 483                 if (!reason)
 484                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);
 485                 sta->plink_state = NL80211_PLINK_HOLDING;
 486                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 487                 spin_unlock_bh(&sta->lock);
 488                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 489                                     sta->sta.addr, llid, plid, reason);
 490                 break;
 491         case NL80211_PLINK_HOLDING:
 492                 /* holding timer */
 493                 del_timer(&sta->plink_timer);
 494                 mesh_plink_fsm_restart(sta);
 495                 spin_unlock_bh(&sta->lock);
 496                 break;
 497         default:
 498                 spin_unlock_bh(&sta->lock);
 499                 break;
 500         }
 501 }
 502
 503 #ifdef CONFIG_PM
 504 void mesh_plink_quiesce(struct sta_info *sta)
 505 {
 506         if (del_timer_sync(&sta->plink_timer))
 507                 sta->plink_timer_was_running = true;
 508 }
 509
 510 void mesh_plink_restart(struct sta_info *sta)
 511 {
 512         if (sta->plink_timer_was_running) {
 513                 add_timer(&sta->plink_timer);
 514                 sta->plink_timer_was_running = false;
 515         }
 516 }
 517 #endif
 518
 519 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 520 {
 521         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 522         sta->plink_timer.data = (unsigned long) sta;
 523         sta->plink_timer.function = mesh_plink_timer;
 524         sta->plink_timeout = timeout;
 525         add_timer(&sta->plink_timer);
 526 }
 527
 528 int mesh_plink_open(struct sta_info *sta)
 529 {
 530         __le16 llid;
 531         struct ieee80211_sub_if_data *sdata = sta->sdata;
 532
 533         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 534                 return -EPERM;
 535
 536         spin_lock_bh(&sta->lock);
 537         get_random_bytes(&llid, 2);
 538         sta->llid = llid;
 539         if (sta->plink_state != NL80211_PLINK_LISTEN &&
 540             sta->plink_state != NL80211_PLINK_BLOCKED) {
 541                 spin_unlock_bh(&sta->lock);
 542                 return -EBUSY;
 543         }
 544         sta->plink_state = NL80211_PLINK_OPN_SNT;
 545         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 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 mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 573         struct ieee802_11_elems elems;
 574         struct sta_info *sta;
 575         enum plink_event event;
 576         enum ieee80211_self_protected_actioncode ftype;
 577         size_t baselen;
 578         bool matches_local = true;
 579         u8 ie_len;
 580         u8 *baseaddr;
 581         u32 changed = 0;
 582         __le16 plid, llid, reason;
 583         static const char *mplstates[] = {
 584                 [NL80211_PLINK_LISTEN] = "LISTEN",
 585                 [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 586                 [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 587                 [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 588                 [NL80211_PLINK_ESTAB] = "ESTAB",
 589                 [NL80211_PLINK_HOLDING] = "HOLDING",
 590                 [NL80211_PLINK_BLOCKED] = "BLOCKED"
 591         };
 592
 593         /* need action_code, aux */
 594         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
 595                 return;
 596
 597         if (is_multicast_ether_addr(mgmt->da)) {
 598                 mpl_dbg(sdata,
 599                         "Mesh plink: ignore frame from multicast address\n");
 600                 return;
 601         }
 602
 603         baseaddr = mgmt->u.action.u.self_prot.variable;
 604         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
 605         if (mgmt->u.action.u.self_prot.action_code ==
 606                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
 607                 baseaddr += 4;
 608                 baselen += 4;
 609         }
 610         ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
 611         if (!elems.peering) {
 612                 mpl_dbg(sdata,
 613                         "Mesh plink: missing necessary peer link ie\n");
 614                 return;
 615         }
 616         if (elems.rsn_len &&
 617                         sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
 618                 mpl_dbg(sdata,
 619                         "Mesh plink: can't establish link with secure peer\n");
 620                 return;
 621         }
 622
 623         ftype = mgmt->u.action.u.self_prot.action_code;
 624         ie_len = elems.peering_len;
 625         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
 626             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
 627             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
 628                                                         && ie_len != 8)) {
 629                 mpl_dbg(sdata,
 630                         "Mesh plink: incorrect plink ie length %d %d\n",
 631                         ftype, ie_len);
 632                 return;
 633         }
 634
 635         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 636                                 (!elems.mesh_id || !elems.mesh_config)) {
 637                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
 638                 return;
 639         }
 640         /* Note the lines below are correct, the llid in the frame is the plid
 641          * from the point of view of this host.
 642          */
 643         memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
 644         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
 645             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
 646                 memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
 647
 648         rcu_read_lock();
 649
 650         sta = sta_info_get(sdata, mgmt->sa);
 651         if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
 652                 mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 653                 rcu_read_unlock();
 654                 return;
 655         }
 656
 657         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
 658             !rssi_threshold_check(sta, sdata)) {
 659                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
 660                         mgmt->sa);
 661                 rcu_read_unlock();
 662                 return;
 663         }
 664
 665         if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
 666                 mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 667                 rcu_read_unlock();
 668                 return;
 669         }
 670
 671         if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
 672                 rcu_read_unlock();
 673                 return;
 674         }
 675
 676         /* Now we will figure out the appropriate event... */
 677         event = PLINK_UNDEFINED;
 678         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 679             !mesh_matches_local(sdata, &elems)) {
 680                 matches_local = false;
 681                 switch (ftype) {
 682                 case WLAN_SP_MESH_PEERING_OPEN:
 683                         event = OPN_RJCT;
 684                         break;
 685                 case WLAN_SP_MESH_PEERING_CONFIRM:
 686                         event = CNF_RJCT;
 687                         break;
 688                 default:
 689                         break;
 690                 }
 691         }
 692
 693         if (!sta && !matches_local) {
 694                 rcu_read_unlock();
 695                 reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 696                 llid = 0;
 697                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 698                                     mgmt->sa, llid, plid, reason);
 699                 return;
 700         } else if (!sta) {
 701                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 702                 if (!mesh_plink_free_count(sdata)) {
 703                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 704                         rcu_read_unlock();
 705                         return;
 706                 }
 707                 event = OPN_ACPT;
 708         } else if (matches_local) {
 709                 switch (ftype) {
 710                 case WLAN_SP_MESH_PEERING_OPEN:
 711                         if (!mesh_plink_free_count(sdata) ||
 712                             (sta->plid && sta->plid != plid))
 713                                 event = OPN_IGNR;
 714                         else
 715                                 event = OPN_ACPT;
 716                         break;
 717                 case WLAN_SP_MESH_PEERING_CONFIRM:
 718                         if (!mesh_plink_free_count(sdata) ||
 719                             (sta->llid != llid || sta->plid != plid))
 720                                 event = CNF_IGNR;
 721                         else
 722                                 event = CNF_ACPT;
 723                         break;
 724                 case WLAN_SP_MESH_PEERING_CLOSE:
 725                         if (sta->plink_state == NL80211_PLINK_ESTAB)
 726                                 /* Do not check for llid or plid. This does not
 727                                  * follow the standard but since multiple plinks
 728                                  * per sta are not supported, it is necessary in
 729                                  * order to avoid a livelock when MP A sees an
 730                                  * establish peer link to MP B but MP B does not
 731                                  * see it. This can be caused by a timeout in
 732                                  * B's peer link establishment or B beign
 733                                  * restarted.
 734                                  */
 735                                 event = CLS_ACPT;
 736                         else if (sta->plid != plid)
 737                                 event = CLS_IGNR;
 738                         else if (ie_len == 7 && sta->llid != llid)
 739                                 event = CLS_IGNR;
 740                         else
 741                                 event = CLS_ACPT;
 742                         break;
 743                 default:
 744                         mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 745                         rcu_read_unlock();
 746                         return;
 747                 }
 748         }
 749
 750         if (event == OPN_ACPT) {
 751                 /* allocate sta entry if necessary and update info */
 752                 sta = mesh_peer_init(sdata, mgmt->sa, &elems);
 753                 if (!sta) {
 754                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
 755                         rcu_read_unlock();
 756                         return;
 757                 }
 758         }
 759
 760         mpl_dbg(sdata,
 761                 "Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
 762                 mgmt->sa, mplstates[sta->plink_state],
 763                 le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
 764                 event);
 765         reason = 0;
 766         spin_lock_bh(&sta->lock);
 767         switch (sta->plink_state) {
 768                 /* spin_unlock as soon as state is updated at each case */
 769         case NL80211_PLINK_LISTEN:
 770                 switch (event) {
 771                 case CLS_ACPT:
 772                         mesh_plink_fsm_restart(sta);
 773                         spin_unlock_bh(&sta->lock);
 774                         break;
 775                 case OPN_ACPT:
 776                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 777                         sta->plid = plid;
 778                         get_random_bytes(&llid, 2);
 779                         sta->llid = llid;
 780                         mesh_plink_timer_set(sta,
 781                                              mshcfg->dot11MeshRetryTimeout);
 782                         spin_unlock_bh(&sta->lock);
 783                         mesh_plink_frame_tx(sdata,
 784                                             WLAN_SP_MESH_PEERING_OPEN,
 785                                             sta->sta.addr, llid, 0, 0);
 786                         mesh_plink_frame_tx(sdata,
 787                                             WLAN_SP_MESH_PEERING_CONFIRM,
 788                                             sta->sta.addr, llid, plid, 0);
 789                         break;
 790                 default:
 791                         spin_unlock_bh(&sta->lock);
 792                         break;
 793                 }
 794                 break;
 795
 796         case NL80211_PLINK_OPN_SNT:
 797                 switch (event) {
 798                 case OPN_RJCT:
 799                 case CNF_RJCT:
 800                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 801                 case CLS_ACPT:
 802                         if (!reason)
 803                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 804                         sta->reason = reason;
 805                         sta->plink_state = NL80211_PLINK_HOLDING;
 806                         if (!mod_plink_timer(sta,
 807                                              mshcfg->dot11MeshHoldingTimeout))
 808                                 sta->ignore_plink_timer = true;
 809
 810                         llid = sta->llid;
 811                         spin_unlock_bh(&sta->lock);
 812                         mesh_plink_frame_tx(sdata,
 813                                             WLAN_SP_MESH_PEERING_CLOSE,
 814                                             sta->sta.addr, llid, plid, reason);
 815                         break;
 816                 case OPN_ACPT:
 817                         /* retry timer is left untouched */
 818                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 819                         sta->plid = plid;
 820                         llid = sta->llid;
 821                         spin_unlock_bh(&sta->lock);
 822                         mesh_plink_frame_tx(sdata,
 823                                             WLAN_SP_MESH_PEERING_CONFIRM,
 824                                             sta->sta.addr, llid, plid, 0);
 825                         break;
 826                 case CNF_ACPT:
 827                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 828                         if (!mod_plink_timer(sta,
 829                                              mshcfg->dot11MeshConfirmTimeout))
 830                                 sta->ignore_plink_timer = true;
 831
 832                         spin_unlock_bh(&sta->lock);
 833                         break;
 834                 default:
 835                         spin_unlock_bh(&sta->lock);
 836                         break;
 837                 }
 838                 break;
 839
 840         case NL80211_PLINK_OPN_RCVD:
 841                 switch (event) {
 842                 case OPN_RJCT:
 843                 case CNF_RJCT:
 844                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 845                 case CLS_ACPT:
 846                         if (!reason)
 847                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 848                         sta->reason = reason;
 849                         sta->plink_state = NL80211_PLINK_HOLDING;
 850                         if (!mod_plink_timer(sta,
 851                                              mshcfg->dot11MeshHoldingTimeout))
 852                                 sta->ignore_plink_timer = true;
 853
 854                         llid = sta->llid;
 855                         spin_unlock_bh(&sta->lock);
 856                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 857                                             sta->sta.addr, llid, plid, reason);
 858                         break;
 859                 case OPN_ACPT:
 860                         llid = sta->llid;
 861                         spin_unlock_bh(&sta->lock);
 862                         mesh_plink_frame_tx(sdata,
 863                                             WLAN_SP_MESH_PEERING_CONFIRM,
 864                                             sta->sta.addr, llid, plid, 0);
 865                         break;
 866                 case CNF_ACPT:
 867                         del_timer(&sta->plink_timer);
 868                         sta->plink_state = NL80211_PLINK_ESTAB;
 869                         spin_unlock_bh(&sta->lock);
 870                         changed |= mesh_plink_inc_estab_count(sdata);
 871                         changed |= mesh_set_ht_prot_mode(sdata);
 872                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 873                                 sta->sta.addr);
 874                         break;
 875                 default:
 876                         spin_unlock_bh(&sta->lock);
 877                         break;
 878                 }
 879                 break;
 880
 881         case NL80211_PLINK_CNF_RCVD:
 882                 switch (event) {
 883                 case OPN_RJCT:
 884                 case CNF_RJCT:
 885                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 886                 case CLS_ACPT:
 887                         if (!reason)
 888                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 889                         sta->reason = reason;
 890                         sta->plink_state = NL80211_PLINK_HOLDING;
 891                         if (!mod_plink_timer(sta,
 892                                              mshcfg->dot11MeshHoldingTimeout))
 893                                 sta->ignore_plink_timer = true;
 894
 895                         llid = sta->llid;
 896                         spin_unlock_bh(&sta->lock);
 897                         mesh_plink_frame_tx(sdata,
 898                                             WLAN_SP_MESH_PEERING_CLOSE,
 899                                             sta->sta.addr, llid, plid, reason);
 900                         break;
 901                 case OPN_ACPT:
 902                         del_timer(&sta->plink_timer);
 903                         sta->plink_state = NL80211_PLINK_ESTAB;
 904                         spin_unlock_bh(&sta->lock);
 905                         changed |= mesh_plink_inc_estab_count(sdata);
 906                         changed |= mesh_set_ht_prot_mode(sdata);
 907                         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 908                                 sta->sta.addr);
 909                         mesh_plink_frame_tx(sdata,
 910                                             WLAN_SP_MESH_PEERING_CONFIRM,
 911                                             sta->sta.addr, llid, plid, 0);
 912                         break;
 913                 default:
 914                         spin_unlock_bh(&sta->lock);
 915                         break;
 916                 }
 917                 break;
 918
 919         case NL80211_PLINK_ESTAB:
 920                 switch (event) {
 921                 case CLS_ACPT:
 922                         reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 923                         sta->reason = reason;
 924                         changed |= __mesh_plink_deactivate(sta);
 925                         sta->plink_state = NL80211_PLINK_HOLDING;
 926                         llid = sta->llid;
 927                         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 928                         spin_unlock_bh(&sta->lock);
 929                         changed |= mesh_set_ht_prot_mode(sdata);
 930                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 931                                             sta->sta.addr, llid, plid, reason);
 932                         break;
 933                 case OPN_ACPT:
 934                         llid = sta->llid;
 935                         spin_unlock_bh(&sta->lock);
 936                         mesh_plink_frame_tx(sdata,
 937                                             WLAN_SP_MESH_PEERING_CONFIRM,
 938                                             sta->sta.addr, llid, plid, 0);
 939                         break;
 940                 default:
 941                         spin_unlock_bh(&sta->lock);
 942                         break;
 943                 }
 944                 break;
 945         case NL80211_PLINK_HOLDING:
 946                 switch (event) {
 947                 case CLS_ACPT:
 948                         if (del_timer(&sta->plink_timer))
 949                                 sta->ignore_plink_timer = 1;
 950                         mesh_plink_fsm_restart(sta);
 951                         spin_unlock_bh(&sta->lock);
 952                         break;
 953                 case OPN_ACPT:
 954                 case CNF_ACPT:
 955                 case OPN_RJCT:
 956                 case CNF_RJCT:
 957                         llid = sta->llid;
 958                         reason = sta->reason;
 959                         spin_unlock_bh(&sta->lock);
 960                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 961                                             sta->sta.addr, llid, plid, reason);
 962                         break;
 963                 default:
 964                         spin_unlock_bh(&sta->lock);
 965                 }
 966                 break;
 967         default:
 968                 /* should not get here, PLINK_BLOCKED is dealt with at the
 969                  * beginning of the function
 970                  */
 971                 spin_unlock_bh(&sta->lock);
 972                 break;
 973         }
 974
 975         rcu_read_unlock();
 976
 977         if (changed)
 978                 ieee80211_bss_info_change_notify(sdata, changed);
 979 }