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
 555         /* If a timer fires just before a state transition on another CPU,
 556          * we may have already extended the timeout and changed state by the
 557          * time we've acquired the lock and arrived  here.  In that case,
 558          * skip this timer and wait for the new one.
 559          */
 560         if (time_before(jiffies, sta->plink_timer.expires)) {
 561                 mpl_dbg(sta->sdata,
 562                         "Ignoring timer for %pM in state %s (timer adjusted)",
 563                         sta->sta.addr, mplstates[sta->plink_state]);
 564                 spin_unlock_bh(&sta->lock);
 565                 return;
 566         }
 567
 568         /* del_timer() and handler may race when entering these states */
 569         if (sta->plink_state == NL80211_PLINK_LISTEN ||
 570             sta->plink_state == NL80211_PLINK_ESTAB) {
 571                 mpl_dbg(sta->sdata,
 572                         "Ignoring timer for %pM in state %s (timer deleted)",
 573                         sta->sta.addr, mplstates[sta->plink_state]);
 574                 spin_unlock_bh(&sta->lock);
 575                 return;
 576         }
 577
 578         mpl_dbg(sta->sdata,
 579                 "Mesh plink timer for %pM fired on state %s\n",
 580                 sta->sta.addr, mplstates[sta->plink_state]);
 581         sdata = sta->sdata;
 582         mshcfg = &sdata->u.mesh.mshcfg;
 583
 584         switch (sta->plink_state) {
 585         case NL80211_PLINK_OPN_RCVD:
 586         case NL80211_PLINK_OPN_SNT:
 587                 /* retry timer */
 588                 if (sta->plink_retries < mshcfg->dot11MeshMaxRetries) {
 589                         u32 rand;
 590                         mpl_dbg(sta->sdata,
 591                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 592                                 sta->sta.addr, sta->plink_retries,
 593                                 sta->plink_timeout);
 594                         get_random_bytes(&rand, sizeof(u32));
 595                         sta->plink_timeout = sta->plink_timeout +
 596                                              rand % sta->plink_timeout;
 597                         ++sta->plink_retries;
 598                         mod_plink_timer(sta, sta->plink_timeout);
 599                         action = WLAN_SP_MESH_PEERING_OPEN;
 600                         break;
 601                 }
 602                 reason = WLAN_REASON_MESH_MAX_RETRIES;
 603                 /* fall through on else */
 604         case NL80211_PLINK_CNF_RCVD:
 605                 /* confirm timer */
 606                 if (!reason)
 607                         reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
 608                 sta->plink_state = NL80211_PLINK_HOLDING;
 609                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 610                 action = WLAN_SP_MESH_PEERING_CLOSE;
 611                 break;
 612         case NL80211_PLINK_HOLDING:
 613                 /* holding timer */
 614                 del_timer(&sta->plink_timer);
 615                 mesh_plink_fsm_restart(sta);
 616                 break;
 617         default:
 618                 break;
 619         }
 620         spin_unlock_bh(&sta->lock);
 621         if (action)
 622                 mesh_plink_frame_tx(sdata, action, sta->sta.addr,
 623                                     sta->llid, sta->plid, reason);
 624 }
 625
 626 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 627 {
 628         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 629         sta->plink_timer.data = (unsigned long) sta;
 630         sta->plink_timer.function = mesh_plink_timer;
 631         sta->plink_timeout = timeout;
 632         add_timer(&sta->plink_timer);
 633 }
 634
 635 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
 636                         u16 llid)
 637 {
 638         struct ieee80211_local *local = sdata->local;
 639         bool in_use = false;
 640         struct sta_info *sta;
 641
 642         rcu_read_lock();
 643         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 644                 if (!memcmp(&sta->llid, &llid, sizeof(llid))) {
 645                         in_use = true;
 646                         break;
 647                 }
 648         }
 649         rcu_read_unlock();
 650
 651         return in_use;
 652 }
 653
 654 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 655 {
 656         u16 llid;
 657
 658         do {
 659                 get_random_bytes(&llid, sizeof(llid));
 660                 /* for mesh PS we still only have the AID range for TIM bits */
 661                 llid = (llid % IEEE80211_MAX_AID) + 1;
 662         } while (llid_in_use(sdata, llid));
 663
 664         return llid;
 665 }
 666
 667 u32 mesh_plink_open(struct sta_info *sta)
 668 {
 669         struct ieee80211_sub_if_data *sdata = sta->sdata;
 670         u32 changed;
 671
 672         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 673                 return 0;
 674
 675         spin_lock_bh(&sta->lock);
 676         sta->llid = mesh_get_new_llid(sdata);
 677         if (sta->plink_state != NL80211_PLINK_LISTEN &&
 678             sta->plink_state != NL80211_PLINK_BLOCKED) {
 679                 spin_unlock_bh(&sta->lock);
 680                 return 0;
 681         }
 682         sta->plink_state = NL80211_PLINK_OPN_SNT;
 683         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 684         spin_unlock_bh(&sta->lock);
 685         mpl_dbg(sdata,
 686                 "Mesh plink: starting establishment with %pM\n",
 687                 sta->sta.addr);
 688
 689         /* set the non-peer mode to active during peering */
 690         changed = ieee80211_mps_local_status_update(sdata);
 691
 692         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 693                             sta->sta.addr, sta->llid, 0, 0);
 694         return changed;
 695 }
 696
 697 u32 mesh_plink_block(struct sta_info *sta)
 698 {
 699         u32 changed;
 700
 701         spin_lock_bh(&sta->lock);
 702         changed = __mesh_plink_deactivate(sta);
 703         sta->plink_state = NL80211_PLINK_BLOCKED;
 704         spin_unlock_bh(&sta->lock);
 705
 706         return changed;
 707 }
 708
 709 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
 710                              struct sta_info *sta,
 711                              enum plink_event event)
 712 {
 713         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 714
 715         u16 reason = (event == CLS_ACPT) ?
 716                      WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
 717
 718         sta->reason = reason;
 719         sta->plink_state = NL80211_PLINK_HOLDING;
 720         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 721 }
 722
 723 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
 724                                 struct sta_info *sta)
 725 {
 726         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 727         u32 changed = 0;
 728
 729         del_timer(&sta->plink_timer);
 730         sta->plink_state = NL80211_PLINK_ESTAB;
 731         changed |= mesh_plink_inc_estab_count(sdata);
 732         changed |= mesh_set_ht_prot_mode(sdata);
 733         changed |= mesh_set_short_slot_time(sdata);
 734         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
 735         ieee80211_mps_sta_status_update(sta);
 736         changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
 737         return changed;
 738 }
 739
 740 /**
 741  * mesh_plink_fsm - step @sta MPM based on @event
 742  *
 743  * @sdata: interface
 744  * @sta: mesh neighbor
 745  * @event: peering event
 746  *
 747  * Return: changed MBSS flags
 748  */
 749 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
 750                           struct sta_info *sta, enum plink_event event)
 751 {
 752         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 753         enum ieee80211_self_protected_actioncode action = 0;
 754         u32 changed = 0;
 755
 756         mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
 757                 mplstates[sta->plink_state], mplevents[event]);
 758
 759         spin_lock_bh(&sta->lock);
 760         switch (sta->plink_state) {
 761         case NL80211_PLINK_LISTEN:
 762                 switch (event) {
 763                 case CLS_ACPT:
 764                         mesh_plink_fsm_restart(sta);
 765                         break;
 766                 case OPN_ACPT:
 767                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 768                         sta->llid = mesh_get_new_llid(sdata);
 769                         mesh_plink_timer_set(sta,
 770                                              mshcfg->dot11MeshRetryTimeout);
 771
 772                         /* set the non-peer mode to active during peering */
 773                         changed |= ieee80211_mps_local_status_update(sdata);
 774                         action = WLAN_SP_MESH_PEERING_OPEN;
 775                         break;
 776                 default:
 777                         break;
 778                 }
 779                 break;
 780         case NL80211_PLINK_OPN_SNT:
 781                 switch (event) {
 782                 case OPN_RJCT:
 783                 case CNF_RJCT:
 784                 case CLS_ACPT:
 785                         mesh_plink_close(sdata, sta, event);
 786                         action = WLAN_SP_MESH_PEERING_CLOSE;
 787                         break;
 788                 case OPN_ACPT:
 789                         /* retry timer is left untouched */
 790                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 791                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 792                         break;
 793                 case CNF_ACPT:
 794                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 795                         mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
 796                         break;
 797                 default:
 798                         break;
 799                 }
 800                 break;
 801         case NL80211_PLINK_OPN_RCVD:
 802                 switch (event) {
 803                 case OPN_RJCT:
 804                 case CNF_RJCT:
 805                 case CLS_ACPT:
 806                         mesh_plink_close(sdata, sta, event);
 807                         action = WLAN_SP_MESH_PEERING_CLOSE;
 808                         break;
 809                 case OPN_ACPT:
 810                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 811                         break;
 812                 case CNF_ACPT:
 813                         changed |= mesh_plink_establish(sdata, sta);
 814                         break;
 815                 default:
 816                         break;
 817                 }
 818                 break;
 819         case NL80211_PLINK_CNF_RCVD:
 820                 switch (event) {
 821                 case OPN_RJCT:
 822                 case CNF_RJCT:
 823                 case CLS_ACPT:
 824                         mesh_plink_close(sdata, sta, event);
 825                         action = WLAN_SP_MESH_PEERING_CLOSE;
 826                         break;
 827                 case OPN_ACPT:
 828                         changed |= mesh_plink_establish(sdata, sta);
 829                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 830                         break;
 831                 default:
 832                         break;
 833                 }
 834                 break;
 835         case NL80211_PLINK_ESTAB:
 836                 switch (event) {
 837                 case CLS_ACPT:
 838                         changed |= __mesh_plink_deactivate(sta);
 839                         changed |= mesh_set_ht_prot_mode(sdata);
 840                         changed |= mesh_set_short_slot_time(sdata);
 841                         mesh_plink_close(sdata, sta, event);
 842                         action = WLAN_SP_MESH_PEERING_CLOSE;
 843                         break;
 844                 case OPN_ACPT:
 845                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 846                         break;
 847                 default:
 848                         break;
 849                 }
 850                 break;
 851         case NL80211_PLINK_HOLDING:
 852                 switch (event) {
 853                 case CLS_ACPT:
 854                         del_timer(&sta->plink_timer);
 855                         mesh_plink_fsm_restart(sta);
 856                         break;
 857                 case OPN_ACPT:
 858                 case CNF_ACPT:
 859                 case OPN_RJCT:
 860                 case CNF_RJCT:
 861                         action = WLAN_SP_MESH_PEERING_CLOSE;
 862                         break;
 863                 default:
 864                         break;
 865                 }
 866                 break;
 867         default:
 868                 /* should not get here, PLINK_BLOCKED is dealt with at the
 869                  * beginning of the function
 870                  */
 871                 break;
 872         }
 873         spin_unlock_bh(&sta->lock);
 874         if (action) {
 875                 mesh_plink_frame_tx(sdata, action, sta->sta.addr,
 876                                     sta->llid, sta->plid, sta->reason);
 877
 878                 /* also send confirm in open case */
 879                 if (action == WLAN_SP_MESH_PEERING_OPEN) {
 880                         mesh_plink_frame_tx(sdata,
 881                                             WLAN_SP_MESH_PEERING_CONFIRM,
 882                                             sta->sta.addr, sta->llid,
 883                                             sta->plid, 0);
 884                 }
 885         }
 886
 887         return changed;
 888 }
 889
 890 /*
 891  * mesh_plink_get_event - get correct MPM event
 892  *
 893  * @sdata: interface
 894  * @sta: peer, leave NULL if processing a frame from a new suitable peer
 895  * @elems: peering management IEs
 896  * @ftype: frame type
 897  * @llid: peer's peer link ID
 898  * @plid: peer's local link ID
 899  *
 900  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
 901  * an error.
 902  */
 903 static enum plink_event
 904 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
 905                      struct sta_info *sta,
 906                      struct ieee802_11_elems *elems,
 907                      enum ieee80211_self_protected_actioncode ftype,
 908                      u16 llid, u16 plid)
 909 {
 910         enum plink_event event = PLINK_UNDEFINED;
 911         u8 ie_len = elems->peering_len;
 912         bool matches_local;
 913
 914         matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
 915                          mesh_matches_local(sdata, elems));
 916
 917         /* deny open request from non-matching peer */
 918         if (!matches_local && !sta) {
 919                 event = OPN_RJCT;
 920                 goto out;
 921         }
 922
 923         if (!sta) {
 924                 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
 925                         mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 926                         goto out;
 927                 }
 928                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 929                 if (!mesh_plink_free_count(sdata)) {
 930                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 931                         goto out;
 932                 }
 933         } else {
 934                 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
 935                         mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 936                         goto out;
 937                 }
 938                 if (sta->plink_state == NL80211_PLINK_BLOCKED)
 939                         goto out;
 940         }
 941
 942         /* new matching peer */
 943         if (!sta) {
 944                 event = OPN_ACPT;
 945                 goto out;
 946         }
 947
 948         switch (ftype) {
 949         case WLAN_SP_MESH_PEERING_OPEN:
 950                 if (!matches_local)
 951                         event = OPN_RJCT;
 952                 if (!mesh_plink_free_count(sdata) ||
 953                     (sta->plid && sta->plid != plid))
 954                         event = OPN_IGNR;
 955                 else
 956                         event = OPN_ACPT;
 957                 break;
 958         case WLAN_SP_MESH_PEERING_CONFIRM:
 959                 if (!matches_local)
 960                         event = CNF_RJCT;
 961                 if (!mesh_plink_free_count(sdata) ||
 962                     (sta->llid != llid || sta->plid != plid))
 963                         event = CNF_IGNR;
 964                 else
 965                         event = CNF_ACPT;
 966                 break;
 967         case WLAN_SP_MESH_PEERING_CLOSE:
 968                 if (sta->plink_state == NL80211_PLINK_ESTAB)
 969                         /* Do not check for llid or plid. This does not
 970                          * follow the standard but since multiple plinks
 971                          * per sta are not supported, it is necessary in
 972                          * order to avoid a livelock when MP A sees an
 973                          * establish peer link to MP B but MP B does not
 974                          * see it. This can be caused by a timeout in
 975                          * B's peer link establishment or B beign
 976                          * restarted.
 977                          */
 978                         event = CLS_ACPT;
 979                 else if (sta->plid != plid)
 980                         event = CLS_IGNR;
 981                 else if (ie_len == 8 && sta->llid != llid)
 982                         event = CLS_IGNR;
 983                 else
 984                         event = CLS_ACPT;
 985                 break;
 986         default:
 987                 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 988                 break;
 989         }
 990
 991 out:
 992         return event;
 993 }
 994
 995 static void
 996 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
 997                          struct ieee80211_mgmt *mgmt,
 998                          struct ieee802_11_elems *elems)
 999 {
1000
1001         struct sta_info *sta;
1002         enum plink_event event;
1003         enum ieee80211_self_protected_actioncode ftype;
1004         u32 changed = 0;
1005         u8 ie_len = elems->peering_len;
1006         __le16 _plid, _llid;
1007         u16 plid, llid = 0;
1008
1009         if (!elems->peering) {
1010                 mpl_dbg(sdata,
1011                         "Mesh plink: missing necessary peer link ie\n");
1012                 return;
1013         }
1014
1015         if (elems->rsn_len &&
1016             sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1017                 mpl_dbg(sdata,
1018                         "Mesh plink: can't establish link with secure peer\n");
1019                 return;
1020         }
1021
1022         ftype = mgmt->u.action.u.self_prot.action_code;
1023         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1024             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1025             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1026                                                         && ie_len != 8)) {
1027                 mpl_dbg(sdata,
1028                         "Mesh plink: incorrect plink ie length %d %d\n",
1029                         ftype, ie_len);
1030                 return;
1031         }
1032
1033         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1034             (!elems->mesh_id || !elems->mesh_config)) {
1035                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1036                 return;
1037         }
1038         /* Note the lines below are correct, the llid in the frame is the plid
1039          * from the point of view of this host.
1040          */
1041         memcpy(&_plid, PLINK_GET_LLID(elems->peering), sizeof(__le16));
1042         plid = le16_to_cpu(_plid);
1043         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1044             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8)) {
1045                 memcpy(&_llid, PLINK_GET_PLID(elems->peering), sizeof(__le16));
1046                 llid = le16_to_cpu(_llid);
1047         }
1048
1049         /* WARNING: Only for sta pointer, is dropped & re-acquired */
1050         rcu_read_lock();
1051
1052         sta = sta_info_get(sdata, mgmt->sa);
1053
1054         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1055             !rssi_threshold_check(sdata, sta)) {
1056                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1057                         mgmt->sa);
1058                 goto unlock_rcu;
1059         }
1060
1061         /* Now we will figure out the appropriate event... */
1062         event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1063
1064         if (event == OPN_ACPT) {
1065                 rcu_read_unlock();
1066                 /* allocate sta entry if necessary and update info */
1067                 sta = mesh_sta_info_get(sdata, mgmt->sa, elems);
1068                 if (!sta) {
1069                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1070                         goto unlock_rcu;
1071                 }
1072                 sta->plid = plid;
1073         } else if (!sta && event == OPN_RJCT) {
1074                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
1075                                     mgmt->sa, 0, plid,
1076                                     WLAN_REASON_MESH_CONFIG);
1077                 goto unlock_rcu;
1078         } else if (!sta || event == PLINK_UNDEFINED) {
1079                 /* something went wrong */
1080                 goto unlock_rcu;
1081         }
1082
1083         changed |= mesh_plink_fsm(sdata, sta, event);
1084
1085 unlock_rcu:
1086         rcu_read_unlock();
1087
1088         if (changed)
1089                 ieee80211_mbss_info_change_notify(sdata, changed);
1090 }
1091
1092 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1093                          struct ieee80211_mgmt *mgmt, size_t len,
1094                          struct ieee80211_rx_status *rx_status)
1095 {
1096         struct ieee802_11_elems elems;
1097         size_t baselen;
1098         u8 *baseaddr;
1099
1100         /* need action_code, aux */
1101         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1102                 return;
1103
1104         if (sdata->u.mesh.user_mpm)
1105                 /* userspace must register for these */
1106                 return;
1107
1108         if (is_multicast_ether_addr(mgmt->da)) {
1109                 mpl_dbg(sdata,
1110                         "Mesh plink: ignore frame from multicast address\n");
1111                 return;
1112         }
1113
1114         baseaddr = mgmt->u.action.u.self_prot.variable;
1115         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1116         if (mgmt->u.action.u.self_prot.action_code ==
1117                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
1118                 baseaddr += 4;
1119                 baselen += 4;
1120         }
1121         ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems);
1122         mesh_process_plink_frame(sdata, mgmt, &elems);
1123 }