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 enum plink_event {
  23         PLINK_UNDEFINED,
  24         OPN_ACPT,
  25         OPN_RJCT,
  26         OPN_IGNR,
  27         CNF_ACPT,
  28         CNF_RJCT,
  29         CNF_IGNR,
  30         CLS_ACPT,
  31         CLS_IGNR
  32 };
  33
  34 static const char * const mplstates[] = {
  35         [NL80211_PLINK_LISTEN] = "LISTEN",
  36         [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
  37         [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
  38         [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
  39         [NL80211_PLINK_ESTAB] = "ESTAB",
  40         [NL80211_PLINK_HOLDING] = "HOLDING",
  41         [NL80211_PLINK_BLOCKED] = "BLOCKED"
  42 };
  43
  44 static const char * const mplevents[] = {
  45         [PLINK_UNDEFINED] = "NONE",
  46         [OPN_ACPT] = "OPN_ACPT",
  47         [OPN_RJCT] = "OPN_RJCT",
  48         [OPN_IGNR] = "OPN_IGNR",
  49         [CNF_ACPT] = "CNF_ACPT",
  50         [CNF_RJCT] = "CNF_RJCT",
  51         [CNF_IGNR] = "CNF_IGNR",
  52         [CLS_ACPT] = "CLS_ACPT",
  53         [CLS_IGNR] = "CLS_IGNR"
  54 };
  55
  56 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
  57                                enum ieee80211_self_protected_actioncode action,
  58                                u8 *da, u16 llid, u16 plid, u16 reason);
  59
  60
  61 /* We only need a valid sta if user configured a minimum rssi_threshold. */
  62 static bool rssi_threshold_check(struct ieee80211_sub_if_data *sdata,
  63                                  struct sta_info *sta)
  64 {
  65         s32 rssi_threshold = sdata->u.mesh.mshcfg.rssi_threshold;
  66         return rssi_threshold == 0 ||
  67                (sta && (s8) -ewma_read(&sta->avg_signal) > rssi_threshold);
  68 }
  69
  70 /**
  71  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  72  *
  73  * @sta: mesh peer link to restart
  74  *
  75  * Locking: this function must be called holding sta->lock
  76  */
  77 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  78 {
  79         sta->plink_state = NL80211_PLINK_LISTEN;
  80         sta->llid = sta->plid = sta->reason = 0;
  81         sta->plink_retries = 0;
  82 }
  83
  84 /*
  85  * mesh_set_short_slot_time - enable / disable ERP short slot time.
  86  *
  87  * The standard indirectly mandates mesh STAs to turn off short slot time by
  88  * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
  89  * can't be sneaky about it. Enable short slot time if all mesh STAs in the
  90  * MBSS support ERP rates.
  91  *
  92  * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
  93  */
  94 static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
  95 {
  96         struct ieee80211_local *local = sdata->local;
  97         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
  98         struct ieee80211_supported_band *sband = local->hw.wiphy->bands[band];
  99         struct sta_info *sta;
 100         u32 erp_rates = 0, changed = 0;
 101         int i;
 102         bool short_slot = false;
 103
 104         if (band == IEEE80211_BAND_5GHZ) {
 105                 /* (IEEE 802.11-2012 19.4.5) */
 106                 short_slot = true;
 107                 goto out;
 108         } else if (band != IEEE80211_BAND_2GHZ ||
 109                    (band == IEEE80211_BAND_2GHZ &&
 110                     local->hw.flags & IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE))
 111                 goto out;
 112
 113         for (i = 0; i < sband->n_bitrates; i++)
 114                 if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
 115                         erp_rates |= BIT(i);
 116
 117         if (!erp_rates)
 118                 goto out;
 119
 120         rcu_read_lock();
 121         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 122                 if (sdata != sta->sdata ||
 123                     sta->plink_state != NL80211_PLINK_ESTAB)
 124                         continue;
 125
 126                 short_slot = false;
 127                 if (erp_rates & sta->sta.supp_rates[band])
 128                         short_slot = true;
 129                  else
 130                         break;
 131         }
 132         rcu_read_unlock();
 133
 134 out:
 135         if (sdata->vif.bss_conf.use_short_slot != short_slot) {
 136                 sdata->vif.bss_conf.use_short_slot = short_slot;
 137                 changed = BSS_CHANGED_ERP_SLOT;
 138                 mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
 139                         sdata->vif.addr, short_slot);
 140         }
 141         return changed;
 142 }
 143
 144 /**
 145  * mesh_set_ht_prot_mode - set correct HT protection mode
 146  *
 147  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 148  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 149  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 150  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 151  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 152  * HT20 peer is present. Otherwise no-protection mode is selected.
 153  */
 154 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 155 {
 156         struct ieee80211_local *local = sdata->local;
 157         struct sta_info *sta;
 158         u16 ht_opmode;
 159         bool non_ht_sta = false, ht20_sta = false;
 160
 161         switch (sdata->vif.bss_conf.chandef.width) {
 162         case NL80211_CHAN_WIDTH_20_NOHT:
 163         case NL80211_CHAN_WIDTH_5:
 164         case NL80211_CHAN_WIDTH_10:
 165                 return 0;
 166         default:
 167                 break;
 168         }
 169
 170         rcu_read_lock();
 171         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 172                 if (sdata != sta->sdata ||
 173                     sta->plink_state != NL80211_PLINK_ESTAB)
 174                         continue;
 175
 176                 if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
 177                         continue;
 178
 179                 if (!sta->sta.ht_cap.ht_supported) {
 180                         mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
 181                                        sta->sta.addr);
 182                         non_ht_sta = true;
 183                         break;
 184                 }
 185
 186                 mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
 187                 ht20_sta = true;
 188         }
 189         rcu_read_unlock();
 190
 191         if (non_ht_sta)
 192                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 193         else if (ht20_sta &&
 194                  sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
 195                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 196         else
 197                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 198
 199         if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
 200                 return 0;
 201
 202         sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 203         sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 204         mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
 205         return BSS_CHANGED_HT;
 206 }
 207
 208 /**
 209  * __mesh_plink_deactivate - deactivate mesh peer link
 210  *
 211  * @sta: mesh peer link to deactivate
 212  *
 213  * All mesh paths with this peer as next hop will be flushed
 214  * Returns beacon changed flag if the beacon content changed.
 215  *
 216  * Locking: the caller must hold sta->lock
 217  */
 218 static u32 __mesh_plink_deactivate(struct sta_info *sta)
 219 {
 220         struct ieee80211_sub_if_data *sdata = sta->sdata;
 221         u32 changed = 0;
 222
 223         if (sta->plink_state == NL80211_PLINK_ESTAB)
 224                 changed = mesh_plink_dec_estab_count(sdata);
 225         sta->plink_state = NL80211_PLINK_BLOCKED;
 226         mesh_path_flush_by_nexthop(sta);
 227
 228         ieee80211_mps_sta_status_update(sta);
 229         changed |= ieee80211_mps_set_sta_local_pm(sta,
 230                         NL80211_MESH_POWER_UNKNOWN);
 231
 232         return changed;
 233 }
 234
 235 /**
 236  * mesh_plink_deactivate - deactivate mesh peer link
 237  *
 238  * @sta: mesh peer link to deactivate
 239  *
 240  * All mesh paths with this peer as next hop will be flushed
 241  */
 242 u32 mesh_plink_deactivate(struct sta_info *sta)
 243 {
 244         struct ieee80211_sub_if_data *sdata = sta->sdata;
 245         u32 changed;
 246
 247         spin_lock_bh(&sta->lock);
 248         changed = __mesh_plink_deactivate(sta);
 249         sta->reason = WLAN_REASON_MESH_PEER_CANCELED;
 250         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 251                             sta->sta.addr, sta->llid, sta->plid,
 252                             sta->reason);
 253         spin_unlock_bh(&sta->lock);
 254
 255         return changed;
 256 }
 257
 258 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 259                                enum ieee80211_self_protected_actioncode action,
 260                                u8 *da, u16 llid, u16 plid, u16 reason)
 261 {
 262         struct ieee80211_local *local = sdata->local;
 263         struct sk_buff *skb;
 264         struct ieee80211_tx_info *info;
 265         struct ieee80211_mgmt *mgmt;
 266         bool include_plid = false;
 267         u16 peering_proto = 0;
 268         u8 *pos, ie_len = 4;
 269         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 270                       sizeof(mgmt->u.action.u.self_prot);
 271         int err = -ENOMEM;
 272
 273         skb = dev_alloc_skb(local->tx_headroom +
 274                             hdr_len +
 275                             2 + /* capability info */
 276                             2 + /* AID */
 277                             2 + 8 + /* supported rates */
 278                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 279                             2 + sdata->u.mesh.mesh_id_len +
 280                             2 + sizeof(struct ieee80211_meshconf_ie) +
 281                             2 + sizeof(struct ieee80211_ht_cap) +
 282                             2 + sizeof(struct ieee80211_ht_operation) +
 283                             2 + 8 + /* peering IE */
 284                             sdata->u.mesh.ie_len);
 285         if (!skb)
 286                 return err;
 287         info = IEEE80211_SKB_CB(skb);
 288         skb_reserve(skb, local->tx_headroom);
 289         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 290         memset(mgmt, 0, hdr_len);
 291         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 292                                           IEEE80211_STYPE_ACTION);
 293         memcpy(mgmt->da, da, ETH_ALEN);
 294         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 295         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 296         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 297         mgmt->u.action.u.self_prot.action_code = action;
 298
 299         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 300                 enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 301
 302                 /* capability info */
 303                 pos = skb_put(skb, 2);
 304                 memset(pos, 0, 2);
 305                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 306                         /* AID */
 307                         pos = skb_put(skb, 2);
 308                         put_unaligned_le16(plid, pos + 2);
 309                 }
 310                 if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
 311                     ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
 312                     mesh_add_rsn_ie(sdata, skb) ||
 313                     mesh_add_meshid_ie(sdata, skb) ||
 314                     mesh_add_meshconf_ie(sdata, skb))
 315                         goto free;
 316         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 317                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
 318                 if (mesh_add_meshid_ie(sdata, skb))
 319                         goto free;
 320         }
 321
 322         /* Add Mesh Peering Management element */
 323         switch (action) {
 324         case WLAN_SP_MESH_PEERING_OPEN:
 325                 break;
 326         case WLAN_SP_MESH_PEERING_CONFIRM:
 327                 ie_len += 2;
 328                 include_plid = true;
 329                 break;
 330         case WLAN_SP_MESH_PEERING_CLOSE:
 331                 if (plid) {
 332                         ie_len += 2;
 333                         include_plid = true;
 334                 }
 335                 ie_len += 2;    /* reason code */
 336                 break;
 337         default:
 338                 err = -EINVAL;
 339                 goto free;
 340         }
 341
 342         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 343                 goto free;
 344
 345         pos = skb_put(skb, 2 + ie_len);
 346         *pos++ = WLAN_EID_PEER_MGMT;
 347         *pos++ = ie_len;
 348         memcpy(pos, &peering_proto, 2);
 349         pos += 2;
 350         put_unaligned_le16(llid, pos);
 351         pos += 2;
 352         if (include_plid) {
 353                 put_unaligned_le16(plid, pos);
 354                 pos += 2;
 355         }
 356         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 357                 put_unaligned_le16(reason, pos);
 358                 pos += 2;
 359         }
 360
 361         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 362                 if (mesh_add_ht_cap_ie(sdata, skb) ||
 363                     mesh_add_ht_oper_ie(sdata, skb))
 364                         goto free;
 365         }
 366
 367         if (mesh_add_vendor_ies(sdata, skb))
 368                 goto free;
 369
 370         ieee80211_tx_skb(sdata, skb);
 371         return 0;
 372 free:
 373         kfree_skb(skb);
 374         return err;
 375 }
 376
 377 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
 378                                struct sta_info *sta,
 379                                struct ieee802_11_elems *elems, bool insert)
 380 {
 381         struct ieee80211_local *local = sdata->local;
 382         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 383         struct ieee80211_supported_band *sband;
 384         u32 rates, basic_rates = 0, changed = 0;
 385
 386         sband = local->hw.wiphy->bands[band];
 387         rates = ieee80211_sta_get_rates(sdata, elems, band, &basic_rates);
 388
 389         spin_lock_bh(&sta->lock);
 390         sta->last_rx = jiffies;
 391
 392         /* rates and capabilities don't change during peering */
 393         if (sta->plink_state == NL80211_PLINK_ESTAB)
 394                 goto out;
 395
 396         if (sta->sta.supp_rates[band] != rates)
 397                 changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
 398         sta->sta.supp_rates[band] = rates;
 399
 400         if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 401                                               elems->ht_cap_elem, sta))
 402                 changed |= IEEE80211_RC_BW_CHANGED;
 403
 404         /* HT peer is operating 20MHz-only */
 405         if (elems->ht_operation &&
 406             !(elems->ht_operation->ht_param &
 407               IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
 408                 if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
 409                         changed |= IEEE80211_RC_BW_CHANGED;
 410                 sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
 411         }
 412
 413         if (insert)
 414                 rate_control_rate_init(sta);
 415         else
 416                 rate_control_rate_update(local, sband, sta, changed);
 417 out:
 418         spin_unlock_bh(&sta->lock);
 419 }
 420
 421 static struct sta_info *
 422 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
 423 {
 424         struct sta_info *sta;
 425
 426         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
 427                 return NULL;
 428
 429         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 430         if (!sta)
 431                 return NULL;
 432
 433         sta->plink_state = NL80211_PLINK_LISTEN;
 434
 435         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 436         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 437         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 438
 439         set_sta_flag(sta, WLAN_STA_WME);
 440         sta->sta.wme = true;
 441
 442         return sta;
 443 }
 444
 445 static struct sta_info *
 446 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
 447                     struct ieee802_11_elems *elems)
 448 {
 449         struct sta_info *sta = NULL;
 450
 451         /* Userspace handles station allocation */
 452         if (sdata->u.mesh.user_mpm ||
 453             sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
 454                 cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 455                                                    elems->ie_start,
 456                                                    elems->total_len,
 457                                                    GFP_KERNEL);
 458         else
 459                 sta = __mesh_sta_info_alloc(sdata, addr);
 460
 461         return sta;
 462 }
 463
 464 /*
 465  * mesh_sta_info_get - return mesh sta info entry for @addr.
 466  *
 467  * @sdata: local meshif
 468  * @addr: peer's address
 469  * @elems: IEs from beacon or mesh peering frame.
 470  *
 471  * Return existing or newly allocated sta_info under RCU read lock.
 472  * (re)initialize with given IEs.
 473  */
 474 static struct sta_info *
 475 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
 476                   u8 *addr, struct ieee802_11_elems *elems) __acquires(RCU)
 477 {
 478         struct sta_info *sta = NULL;
 479
 480         rcu_read_lock();
 481         sta = sta_info_get(sdata, addr);
 482         if (sta) {
 483                 mesh_sta_info_init(sdata, sta, elems, false);
 484         } else {
 485                 rcu_read_unlock();
 486                 /* can't run atomic */
 487                 sta = mesh_sta_info_alloc(sdata, addr, elems);
 488                 if (!sta) {
 489                         rcu_read_lock();
 490                         return NULL;
 491                 }
 492
 493                 mesh_sta_info_init(sdata, sta, elems, true);
 494
 495                 if (sta_info_insert_rcu(sta))
 496                         return NULL;
 497         }
 498
 499         return sta;
 500 }
 501
 502 /*
 503  * mesh_neighbour_update - update or initialize new mesh neighbor.
 504  *
 505  * @sdata: local meshif
 506  * @addr: peer's address
 507  * @elems: IEs from beacon or mesh peering frame
 508  *
 509  * Initiates peering if appropriate.
 510  */
 511 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 512                            u8 *hw_addr,
 513                            struct ieee802_11_elems *elems)
 514 {
 515         struct sta_info *sta;
 516         u32 changed = 0;
 517
 518         sta = mesh_sta_info_get(sdata, hw_addr, elems);
 519         if (!sta)
 520                 goto out;
 521
 522         if (mesh_peer_accepts_plinks(elems) &&
 523             sta->plink_state == NL80211_PLINK_LISTEN &&
 524             sdata->u.mesh.accepting_plinks &&
 525             sdata->u.mesh.mshcfg.auto_open_plinks &&
 526             rssi_threshold_check(sdata, sta))
 527                 changed = mesh_plink_open(sta);
 528
 529         ieee80211_mps_frame_release(sta, elems);
 530 out:
 531         rcu_read_unlock();
 532         ieee80211_mbss_info_change_notify(sdata, changed);
 533 }
 534
 535 static void mesh_plink_timer(unsigned long data)
 536 {
 537         struct sta_info *sta;
 538         u16 reason = 0;
 539         struct ieee80211_sub_if_data *sdata;
 540         struct mesh_config *mshcfg;
 541         enum ieee80211_self_protected_actioncode action = 0;
 542
 543         /*
 544          * This STA is valid because sta_info_destroy() will
 545          * del_timer_sync() this timer after having made sure
 546          * it cannot be readded (by deleting the plink.)
 547          */
 548         sta = (struct sta_info *) data;
 549
 550         if (sta->sdata->local->quiescing)
 551                 return;
 552
 553         spin_lock_bh(&sta->lock);
 554         if (sta->ignore_plink_timer) {
 555                 sta->ignore_plink_timer = false;
 556                 spin_unlock_bh(&sta->lock);
 557                 return;
 558         }
 559         mpl_dbg(sta->sdata,
 560                 "Mesh plink timer for %pM fired on state %s\n",
 561                 sta->sta.addr, mplstates[sta->plink_state]);
 562         sdata = sta->sdata;
 563         mshcfg = &sdata->u.mesh.mshcfg;
 564
 565         switch (sta->plink_state) {
 566         case NL80211_PLINK_OPN_RCVD:
 567         case NL80211_PLINK_OPN_SNT:
 568                 /* retry timer */
 569                 if (sta->plink_retries < mshcfg->dot11MeshMaxRetries) {
 570                         u32 rand;
 571                         mpl_dbg(sta->sdata,
 572                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 573                                 sta->sta.addr, sta->plink_retries,
 574                                 sta->plink_timeout);
 575                         get_random_bytes(&rand, sizeof(u32));
 576                         sta->plink_timeout = sta->plink_timeout +
 577                                              rand % sta->plink_timeout;
 578                         ++sta->plink_retries;
 579                         mod_plink_timer(sta, sta->plink_timeout);
 580                         action = WLAN_SP_MESH_PEERING_OPEN;
 581                         break;
 582                 }
 583                 reason = WLAN_REASON_MESH_MAX_RETRIES;
 584                 /* fall through on else */
 585         case NL80211_PLINK_CNF_RCVD:
 586                 /* confirm timer */
 587                 if (!reason)
 588                         reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
 589                 sta->plink_state = NL80211_PLINK_HOLDING;
 590                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 591                 action = WLAN_SP_MESH_PEERING_CLOSE;
 592                 break;
 593         case NL80211_PLINK_HOLDING:
 594                 /* holding timer */
 595                 del_timer(&sta->plink_timer);
 596                 mesh_plink_fsm_restart(sta);
 597                 break;
 598         default:
 599                 break;
 600         }
 601         spin_unlock_bh(&sta->lock);
 602         if (action)
 603                 mesh_plink_frame_tx(sdata, action, sta->sta.addr,
 604                                     sta->llid, sta->plid, reason);
 605 }
 606
 607 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 608 {
 609         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 610         sta->plink_timer.data = (unsigned long) sta;
 611         sta->plink_timer.function = mesh_plink_timer;
 612         sta->plink_timeout = timeout;
 613         add_timer(&sta->plink_timer);
 614 }
 615
 616 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
 617                         u16 llid)
 618 {
 619         struct ieee80211_local *local = sdata->local;
 620         bool in_use = false;
 621         struct sta_info *sta;
 622
 623         rcu_read_lock();
 624         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 625                 if (!memcmp(&sta->llid, &llid, sizeof(llid))) {
 626                         in_use = true;
 627                         break;
 628                 }
 629         }
 630         rcu_read_unlock();
 631
 632         return in_use;
 633 }
 634
 635 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 636 {
 637         u16 llid;
 638
 639         do {
 640                 get_random_bytes(&llid, sizeof(llid));
 641                 /* for mesh PS we still only have the AID range for TIM bits */
 642                 llid = (llid % IEEE80211_MAX_AID) + 1;
 643         } while (llid_in_use(sdata, llid));
 644
 645         return llid;
 646 }
 647
 648 u32 mesh_plink_open(struct sta_info *sta)
 649 {
 650         struct ieee80211_sub_if_data *sdata = sta->sdata;
 651         u32 changed;
 652
 653         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 654                 return 0;
 655
 656         spin_lock_bh(&sta->lock);
 657         sta->llid = mesh_get_new_llid(sdata);
 658         if (sta->plink_state != NL80211_PLINK_LISTEN &&
 659             sta->plink_state != NL80211_PLINK_BLOCKED) {
 660                 spin_unlock_bh(&sta->lock);
 661                 return 0;
 662         }
 663         sta->plink_state = NL80211_PLINK_OPN_SNT;
 664         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 665         spin_unlock_bh(&sta->lock);
 666         mpl_dbg(sdata,
 667                 "Mesh plink: starting establishment with %pM\n",
 668                 sta->sta.addr);
 669
 670         /* set the non-peer mode to active during peering */
 671         changed = ieee80211_mps_local_status_update(sdata);
 672
 673         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 674                             sta->sta.addr, sta->llid, 0, 0);
 675         return changed;
 676 }
 677
 678 u32 mesh_plink_block(struct sta_info *sta)
 679 {
 680         u32 changed;
 681
 682         spin_lock_bh(&sta->lock);
 683         changed = __mesh_plink_deactivate(sta);
 684         sta->plink_state = NL80211_PLINK_BLOCKED;
 685         spin_unlock_bh(&sta->lock);
 686
 687         return changed;
 688 }
 689
 690 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
 691                              struct sta_info *sta,
 692                              enum plink_event event)
 693 {
 694         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 695
 696         u16 reason = (event == CLS_ACPT) ?
 697                      WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
 698
 699         sta->reason = reason;
 700         sta->plink_state = NL80211_PLINK_HOLDING;
 701         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 702 }
 703
 704 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
 705                                 struct sta_info *sta)
 706 {
 707         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 708         u32 changed = 0;
 709
 710         del_timer(&sta->plink_timer);
 711         sta->plink_state = NL80211_PLINK_ESTAB;
 712         changed |= mesh_plink_inc_estab_count(sdata);
 713         changed |= mesh_set_ht_prot_mode(sdata);
 714         changed |= mesh_set_short_slot_time(sdata);
 715         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
 716         ieee80211_mps_sta_status_update(sta);
 717         changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
 718         return changed;
 719 }
 720
 721 /**
 722  * mesh_plink_fsm - step @sta MPM based on @event
 723  *
 724  * @sdata: interface
 725  * @sta: mesh neighbor
 726  * @event: peering event
 727  *
 728  * Return: changed MBSS flags
 729  */
 730 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
 731                           struct sta_info *sta, enum plink_event event)
 732 {
 733         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 734         enum ieee80211_self_protected_actioncode action = 0;
 735         u32 changed = 0;
 736
 737         mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
 738                 mplstates[sta->plink_state], mplevents[event]);
 739
 740         spin_lock_bh(&sta->lock);
 741         switch (sta->plink_state) {
 742         case NL80211_PLINK_LISTEN:
 743                 switch (event) {
 744                 case CLS_ACPT:
 745                         mesh_plink_fsm_restart(sta);
 746                         break;
 747                 case OPN_ACPT:
 748                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 749                         sta->llid = mesh_get_new_llid(sdata);
 750                         mesh_plink_timer_set(sta,
 751                                              mshcfg->dot11MeshRetryTimeout);
 752
 753                         /* set the non-peer mode to active during peering */
 754                         changed |= ieee80211_mps_local_status_update(sdata);
 755                         action = WLAN_SP_MESH_PEERING_OPEN;
 756                         break;
 757                 default:
 758                         break;
 759                 }
 760                 break;
 761         case NL80211_PLINK_OPN_SNT:
 762                 switch (event) {
 763                 case OPN_RJCT:
 764                 case CNF_RJCT:
 765                 case CLS_ACPT:
 766                         mesh_plink_close(sdata, sta, event);
 767                         action = WLAN_SP_MESH_PEERING_CLOSE;
 768                         break;
 769                 case OPN_ACPT:
 770                         /* retry timer is left untouched */
 771                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 772                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 773                         break;
 774                 case CNF_ACPT:
 775                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 776                         if (!mod_plink_timer(sta,
 777                                              mshcfg->dot11MeshConfirmTimeout))
 778                                 sta->ignore_plink_timer = true;
 779                         break;
 780                 default:
 781                         break;
 782                 }
 783                 break;
 784         case NL80211_PLINK_OPN_RCVD:
 785                 switch (event) {
 786                 case OPN_RJCT:
 787                 case CNF_RJCT:
 788                 case CLS_ACPT:
 789                         mesh_plink_close(sdata, sta, event);
 790                         action = WLAN_SP_MESH_PEERING_CLOSE;
 791                         break;
 792                 case OPN_ACPT:
 793                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 794                         break;
 795                 case CNF_ACPT:
 796                         changed |= mesh_plink_establish(sdata, sta);
 797                         break;
 798                 default:
 799                         break;
 800                 }
 801                 break;
 802         case NL80211_PLINK_CNF_RCVD:
 803                 switch (event) {
 804                 case OPN_RJCT:
 805                 case CNF_RJCT:
 806                 case CLS_ACPT:
 807                         mesh_plink_close(sdata, sta, event);
 808                         action = WLAN_SP_MESH_PEERING_CLOSE;
 809                         break;
 810                 case OPN_ACPT:
 811                         changed |= mesh_plink_establish(sdata, sta);
 812                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 813                         break;
 814                 default:
 815                         break;
 816                 }
 817                 break;
 818         case NL80211_PLINK_ESTAB:
 819                 switch (event) {
 820                 case CLS_ACPT:
 821                         changed |= __mesh_plink_deactivate(sta);
 822                         changed |= mesh_set_ht_prot_mode(sdata);
 823                         changed |= mesh_set_short_slot_time(sdata);
 824                         mesh_plink_close(sdata, sta, event);
 825                         action = WLAN_SP_MESH_PEERING_CLOSE;
 826                         break;
 827                 case OPN_ACPT:
 828                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 829                         break;
 830                 default:
 831                         break;
 832                 }
 833                 break;
 834         case NL80211_PLINK_HOLDING:
 835                 switch (event) {
 836                 case CLS_ACPT:
 837                         if (del_timer(&sta->plink_timer))
 838                                 sta->ignore_plink_timer = 1;
 839                         mesh_plink_fsm_restart(sta);
 840                         break;
 841                 case OPN_ACPT:
 842                 case CNF_ACPT:
 843                 case OPN_RJCT:
 844                 case CNF_RJCT:
 845                         action = WLAN_SP_MESH_PEERING_CLOSE;
 846                         break;
 847                 default:
 848                         break;
 849                 }
 850                 break;
 851         default:
 852                 /* should not get here, PLINK_BLOCKED is dealt with at the
 853                  * beginning of the function
 854                  */
 855                 break;
 856         }
 857         spin_unlock_bh(&sta->lock);
 858         if (action) {
 859                 mesh_plink_frame_tx(sdata, action, sta->sta.addr,
 860                                     sta->llid, sta->plid, sta->reason);
 861
 862                 /* also send confirm in open case */
 863                 if (action == WLAN_SP_MESH_PEERING_OPEN) {
 864                         mesh_plink_frame_tx(sdata,
 865                                             WLAN_SP_MESH_PEERING_CONFIRM,
 866                                             sta->sta.addr, sta->llid,
 867                                             sta->plid, 0);
 868                 }
 869         }
 870
 871         return changed;
 872 }
 873
 874 /*
 875  * mesh_plink_get_event - get correct MPM event
 876  *
 877  * @sdata: interface
 878  * @sta: peer, leave NULL if processing a frame from a new suitable peer
 879  * @elems: peering management IEs
 880  * @ftype: frame type
 881  * @llid: peer's peer link ID
 882  * @plid: peer's local link ID
 883  *
 884  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
 885  * an error.
 886  */
 887 static enum plink_event
 888 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
 889                      struct sta_info *sta,
 890                      struct ieee802_11_elems *elems,
 891                      enum ieee80211_self_protected_actioncode ftype,
 892                      u16 llid, u16 plid)
 893 {
 894         enum plink_event event = PLINK_UNDEFINED;
 895         u8 ie_len = elems->peering_len;
 896         bool matches_local;
 897
 898         matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
 899                          mesh_matches_local(sdata, elems));
 900
 901         /* deny open request from non-matching peer */
 902         if (!matches_local && !sta) {
 903                 event = OPN_RJCT;
 904                 goto out;
 905         }
 906
 907         if (!sta) {
 908                 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
 909                         mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 910                         goto out;
 911                 }
 912                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 913                 if (!mesh_plink_free_count(sdata)) {
 914                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 915                         goto out;
 916                 }
 917         } else {
 918                 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
 919                         mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 920                         goto out;
 921                 }
 922                 if (sta->plink_state == NL80211_PLINK_BLOCKED)
 923                         goto out;
 924         }
 925
 926         /* new matching peer */
 927         if (!sta) {
 928                 event = OPN_ACPT;
 929                 goto out;
 930         }
 931
 932         switch (ftype) {
 933         case WLAN_SP_MESH_PEERING_OPEN:
 934                 if (!matches_local)
 935                         event = OPN_RJCT;
 936                 if (!mesh_plink_free_count(sdata) ||
 937                     (sta->plid && sta->plid != plid))
 938                         event = OPN_IGNR;
 939                 else
 940                         event = OPN_ACPT;
 941                 break;
 942         case WLAN_SP_MESH_PEERING_CONFIRM:
 943                 if (!matches_local)
 944                         event = CNF_RJCT;
 945                 if (!mesh_plink_free_count(sdata) ||
 946                     (sta->llid != llid || sta->plid != plid))
 947                         event = CNF_IGNR;
 948                 else
 949                         event = CNF_ACPT;
 950                 break;
 951         case WLAN_SP_MESH_PEERING_CLOSE:
 952                 if (sta->plink_state == NL80211_PLINK_ESTAB)
 953                         /* Do not check for llid or plid. This does not
 954                          * follow the standard but since multiple plinks
 955                          * per sta are not supported, it is necessary in
 956                          * order to avoid a livelock when MP A sees an
 957                          * establish peer link to MP B but MP B does not
 958                          * see it. This can be caused by a timeout in
 959                          * B's peer link establishment or B beign
 960                          * restarted.
 961                          */
 962                         event = CLS_ACPT;
 963                 else if (sta->plid != plid)
 964                         event = CLS_IGNR;
 965                 else if (ie_len == 8 && sta->llid != llid)
 966                         event = CLS_IGNR;
 967                 else
 968                         event = CLS_ACPT;
 969                 break;
 970         default:
 971                 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 972                 break;
 973         }
 974
 975 out:
 976         return event;
 977 }
 978
 979 static void
 980 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
 981                          struct ieee80211_mgmt *mgmt,
 982                          struct ieee802_11_elems *elems)
 983 {
 984
 985         struct sta_info *sta;
 986         enum plink_event event;
 987         enum ieee80211_self_protected_actioncode ftype;
 988         u32 changed = 0;
 989         u8 ie_len = elems->peering_len;
 990         __le16 _plid, _llid;
 991         u16 plid, llid = 0;
 992
 993         if (!elems->peering) {
 994                 mpl_dbg(sdata,
 995                         "Mesh plink: missing necessary peer link ie\n");
 996                 return;
 997         }
 998
 999         if (elems->rsn_len &&
1000             sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1001                 mpl_dbg(sdata,
1002                         "Mesh plink: can't establish link with secure peer\n");
1003                 return;
1004         }
1005
1006         ftype = mgmt->u.action.u.self_prot.action_code;
1007         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1008             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1009             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1010                                                         && ie_len != 8)) {
1011                 mpl_dbg(sdata,
1012                         "Mesh plink: incorrect plink ie length %d %d\n",
1013                         ftype, ie_len);
1014                 return;
1015         }
1016
1017         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1018             (!elems->mesh_id || !elems->mesh_config)) {
1019                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1020                 return;
1021         }
1022         /* Note the lines below are correct, the llid in the frame is the plid
1023          * from the point of view of this host.
1024          */
1025         memcpy(&_plid, PLINK_GET_LLID(elems->peering), sizeof(__le16));
1026         plid = le16_to_cpu(_plid);
1027         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1028             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8)) {
1029                 memcpy(&_llid, PLINK_GET_PLID(elems->peering), sizeof(__le16));
1030                 llid = le16_to_cpu(_llid);
1031         }
1032
1033         /* WARNING: Only for sta pointer, is dropped & re-acquired */
1034         rcu_read_lock();
1035
1036         sta = sta_info_get(sdata, mgmt->sa);
1037
1038         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1039             !rssi_threshold_check(sdata, sta)) {
1040                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1041                         mgmt->sa);
1042                 goto unlock_rcu;
1043         }
1044
1045         /* Now we will figure out the appropriate event... */
1046         event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1047
1048         if (event == OPN_ACPT) {
1049                 rcu_read_unlock();
1050                 /* allocate sta entry if necessary and update info */
1051                 sta = mesh_sta_info_get(sdata, mgmt->sa, elems);
1052                 if (!sta) {
1053                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1054                         goto unlock_rcu;
1055                 }
1056                 sta->plid = plid;
1057         } else if (!sta && event == OPN_RJCT) {
1058                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
1059                                     mgmt->sa, 0, plid,
1060                                     WLAN_REASON_MESH_CONFIG);
1061                 goto unlock_rcu;
1062         } else if (!sta || event == PLINK_UNDEFINED) {
1063                 /* something went wrong */
1064                 goto unlock_rcu;
1065         }
1066
1067         changed |= mesh_plink_fsm(sdata, sta, event);
1068
1069 unlock_rcu:
1070         rcu_read_unlock();
1071
1072         if (changed)
1073                 ieee80211_mbss_info_change_notify(sdata, changed);
1074 }
1075
1076 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1077                          struct ieee80211_mgmt *mgmt, size_t len,
1078                          struct ieee80211_rx_status *rx_status)
1079 {
1080         struct ieee802_11_elems elems;
1081         size_t baselen;
1082         u8 *baseaddr;
1083
1084         /* need action_code, aux */
1085         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1086                 return;
1087
1088         if (sdata->u.mesh.user_mpm)
1089                 /* userspace must register for these */
1090                 return;
1091
1092         if (is_multicast_ether_addr(mgmt->da)) {
1093                 mpl_dbg(sdata,
1094                         "Mesh plink: ignore frame from multicast address\n");
1095                 return;
1096         }
1097
1098         baseaddr = mgmt->u.action.u.self_prot.variable;
1099         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1100         if (mgmt->u.action.u.self_prot.action_code ==
1101                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
1102                 baseaddr += 4;
1103                 baselen += 4;
1104         }
1105         ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems);
1106         mesh_process_plink_frame(sdata, mgmt, &elems);
1107 }