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 + msecs_to_jiffies(t)))
  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->plink_lock
  76  */
  77 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  78 {
  79         lockdep_assert_held(&sta->plink_lock);
  80         sta->plink_state = NL80211_PLINK_LISTEN;
  81         sta->llid = sta->plid = sta->reason = 0;
  82         sta->plink_retries = 0;
  83 }
  84
  85 /*
  86  * mesh_set_short_slot_time - enable / disable ERP short slot time.
  87  *
  88  * The standard indirectly mandates mesh STAs to turn off short slot time by
  89  * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
  90  * can't be sneaky about it. Enable short slot time if all mesh STAs in the
  91  * MBSS support ERP rates.
  92  *
  93  * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
  94  */
  95 static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
  96 {
  97         struct ieee80211_local *local = sdata->local;
  98         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
  99         struct ieee80211_supported_band *sband = local->hw.wiphy->bands[band];
 100         struct sta_info *sta;
 101         u32 erp_rates = 0, changed = 0;
 102         int i;
 103         bool short_slot = false;
 104
 105         if (band == IEEE80211_BAND_5GHZ) {
 106                 /* (IEEE 802.11-2012 19.4.5) */
 107                 short_slot = true;
 108                 goto out;
 109         } else if (band != IEEE80211_BAND_2GHZ)
 110                 goto out;
 111
 112         for (i = 0; i < sband->n_bitrates; i++)
 113                 if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
 114                         erp_rates |= BIT(i);
 115
 116         if (!erp_rates)
 117                 goto out;
 118
 119         rcu_read_lock();
 120         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 121                 if (sdata != sta->sdata ||
 122                     sta->plink_state != NL80211_PLINK_ESTAB)
 123                         continue;
 124
 125                 short_slot = false;
 126                 if (erp_rates & sta->sta.supp_rates[band])
 127                         short_slot = true;
 128                  else
 129                         break;
 130         }
 131         rcu_read_unlock();
 132
 133 out:
 134         if (sdata->vif.bss_conf.use_short_slot != short_slot) {
 135                 sdata->vif.bss_conf.use_short_slot = short_slot;
 136                 changed = BSS_CHANGED_ERP_SLOT;
 137                 mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
 138                         sdata->vif.addr, short_slot);
 139         }
 140         return changed;
 141 }
 142
 143 /**
 144  * mesh_set_ht_prot_mode - set correct HT protection mode
 145  *
 146  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 147  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 148  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 149  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 150  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 151  * HT20 peer is present. Otherwise no-protection mode is selected.
 152  */
 153 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 154 {
 155         struct ieee80211_local *local = sdata->local;
 156         struct sta_info *sta;
 157         u16 ht_opmode;
 158         bool non_ht_sta = false, ht20_sta = false;
 159
 160         switch (sdata->vif.bss_conf.chandef.width) {
 161         case NL80211_CHAN_WIDTH_20_NOHT:
 162         case NL80211_CHAN_WIDTH_5:
 163         case NL80211_CHAN_WIDTH_10:
 164                 return 0;
 165         default:
 166                 break;
 167         }
 168
 169         rcu_read_lock();
 170         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 171                 if (sdata != sta->sdata ||
 172                     sta->plink_state != NL80211_PLINK_ESTAB)
 173                         continue;
 174
 175                 if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
 176                         continue;
 177
 178                 if (!sta->sta.ht_cap.ht_supported) {
 179                         mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
 180                                        sta->sta.addr);
 181                         non_ht_sta = true;
 182                         break;
 183                 }
 184
 185                 mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
 186                 ht20_sta = true;
 187         }
 188         rcu_read_unlock();
 189
 190         if (non_ht_sta)
 191                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 192         else if (ht20_sta &&
 193                  sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
 194                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 195         else
 196                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 197
 198         if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
 199                 return 0;
 200
 201         sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 202         sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 203         mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
 204         return BSS_CHANGED_HT;
 205 }
 206
 207 /**
 208  * __mesh_plink_deactivate - deactivate mesh peer link
 209  *
 210  * @sta: mesh peer link to deactivate
 211  *
 212  * All mesh paths with this peer as next hop will be flushed
 213  * Returns beacon changed flag if the beacon content changed.
 214  *
 215  * Locking: the caller must hold sta->plink_lock
 216  */
 217 static u32 __mesh_plink_deactivate(struct sta_info *sta)
 218 {
 219         struct ieee80211_sub_if_data *sdata = sta->sdata;
 220         u32 changed = 0;
 221
 222         lockdep_assert_held(&sta->plink_lock);
 223
 224         if (sta->plink_state == NL80211_PLINK_ESTAB)
 225                 changed = mesh_plink_dec_estab_count(sdata);
 226         sta->plink_state = NL80211_PLINK_BLOCKED;
 227         mesh_path_flush_by_nexthop(sta);
 228
 229         ieee80211_mps_sta_status_update(sta);
 230         changed |= ieee80211_mps_set_sta_local_pm(sta,
 231                         NL80211_MESH_POWER_UNKNOWN);
 232
 233         return changed;
 234 }
 235
 236 /**
 237  * mesh_plink_deactivate - deactivate mesh peer link
 238  *
 239  * @sta: mesh peer link to deactivate
 240  *
 241  * All mesh paths with this peer as next hop will be flushed
 242  */
 243 u32 mesh_plink_deactivate(struct sta_info *sta)
 244 {
 245         struct ieee80211_sub_if_data *sdata = sta->sdata;
 246         u32 changed;
 247
 248         spin_lock_bh(&sta->plink_lock);
 249         changed = __mesh_plink_deactivate(sta);
 250         sta->reason = WLAN_REASON_MESH_PEER_CANCELED;
 251         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 252                             sta->sta.addr, sta->llid, sta->plid,
 253                             sta->reason);
 254         spin_unlock_bh(&sta->plink_lock);
 255
 256         return changed;
 257 }
 258
 259 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 260                                enum ieee80211_self_protected_actioncode action,
 261                                u8 *da, u16 llid, u16 plid, u16 reason)
 262 {
 263         struct ieee80211_local *local = sdata->local;
 264         struct sk_buff *skb;
 265         struct ieee80211_tx_info *info;
 266         struct ieee80211_mgmt *mgmt;
 267         bool include_plid = false;
 268         u16 peering_proto = 0;
 269         u8 *pos, ie_len = 4;
 270         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 271                       sizeof(mgmt->u.action.u.self_prot);
 272         int err = -ENOMEM;
 273
 274         skb = dev_alloc_skb(local->tx_headroom +
 275                             hdr_len +
 276                             2 + /* capability info */
 277                             2 + /* AID */
 278                             2 + 8 + /* supported rates */
 279                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 280                             2 + sdata->u.mesh.mesh_id_len +
 281                             2 + sizeof(struct ieee80211_meshconf_ie) +
 282                             2 + sizeof(struct ieee80211_ht_cap) +
 283                             2 + sizeof(struct ieee80211_ht_operation) +
 284                             2 + 8 + /* peering IE */
 285                             sdata->u.mesh.ie_len);
 286         if (!skb)
 287                 return err;
 288         info = IEEE80211_SKB_CB(skb);
 289         skb_reserve(skb, local->tx_headroom);
 290         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 291         memset(mgmt, 0, hdr_len);
 292         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 293                                           IEEE80211_STYPE_ACTION);
 294         memcpy(mgmt->da, da, ETH_ALEN);
 295         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 296         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 297         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 298         mgmt->u.action.u.self_prot.action_code = action;
 299
 300         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 301                 enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 302
 303                 /* capability info */
 304                 pos = skb_put(skb, 2);
 305                 memset(pos, 0, 2);
 306                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 307                         /* AID */
 308                         pos = skb_put(skb, 2);
 309                         put_unaligned_le16(plid, pos);
 310                 }
 311                 if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
 312                     ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
 313                     mesh_add_rsn_ie(sdata, skb) ||
 314                     mesh_add_meshid_ie(sdata, skb) ||
 315                     mesh_add_meshconf_ie(sdata, skb))
 316                         goto free;
 317         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 318                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
 319                 if (mesh_add_meshid_ie(sdata, skb))
 320                         goto free;
 321         }
 322
 323         /* Add Mesh Peering Management element */
 324         switch (action) {
 325         case WLAN_SP_MESH_PEERING_OPEN:
 326                 break;
 327         case WLAN_SP_MESH_PEERING_CONFIRM:
 328                 ie_len += 2;
 329                 include_plid = true;
 330                 break;
 331         case WLAN_SP_MESH_PEERING_CLOSE:
 332                 if (plid) {
 333                         ie_len += 2;
 334                         include_plid = true;
 335                 }
 336                 ie_len += 2;    /* reason code */
 337                 break;
 338         default:
 339                 err = -EINVAL;
 340                 goto free;
 341         }
 342
 343         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 344                 goto free;
 345
 346         pos = skb_put(skb, 2 + ie_len);
 347         *pos++ = WLAN_EID_PEER_MGMT;
 348         *pos++ = ie_len;
 349         memcpy(pos, &peering_proto, 2);
 350         pos += 2;
 351         put_unaligned_le16(llid, pos);
 352         pos += 2;
 353         if (include_plid) {
 354                 put_unaligned_le16(plid, pos);
 355                 pos += 2;
 356         }
 357         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 358                 put_unaligned_le16(reason, pos);
 359                 pos += 2;
 360         }
 361
 362         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 363                 if (mesh_add_ht_cap_ie(sdata, skb) ||
 364                     mesh_add_ht_oper_ie(sdata, skb))
 365                         goto free;
 366         }
 367
 368         if (mesh_add_vendor_ies(sdata, skb))
 369                 goto free;
 370
 371         ieee80211_tx_skb(sdata, skb);
 372         return 0;
 373 free:
 374         kfree_skb(skb);
 375         return err;
 376 }
 377
 378 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
 379                                struct sta_info *sta,
 380                                struct ieee802_11_elems *elems, bool insert)
 381 {
 382         struct ieee80211_local *local = sdata->local;
 383         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 384         struct ieee80211_supported_band *sband;
 385         u32 rates, basic_rates = 0, changed = 0;
 386         enum ieee80211_sta_rx_bandwidth bw = sta->sta.bandwidth;
 387
 388         sband = local->hw.wiphy->bands[band];
 389         rates = ieee80211_sta_get_rates(sdata, elems, band, &basic_rates);
 390
 391         spin_lock_bh(&sta->plink_lock);
 392         sta->last_rx = jiffies;
 393
 394         /* rates and capabilities don't change during peering */
 395         if (sta->plink_state == NL80211_PLINK_ESTAB && sta->processed_beacon)
 396                 goto out;
 397         sta->processed_beacon = true;
 398
 399         if (sta->sta.supp_rates[band] != rates)
 400                 changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
 401         sta->sta.supp_rates[band] = rates;
 402
 403         if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 404                                               elems->ht_cap_elem, sta))
 405                 changed |= IEEE80211_RC_BW_CHANGED;
 406
 407         if (bw != sta->sta.bandwidth)
 408                 changed |= IEEE80211_RC_BW_CHANGED;
 409
 410         /* HT peer is operating 20MHz-only */
 411         if (elems->ht_operation &&
 412             !(elems->ht_operation->ht_param &
 413               IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
 414                 if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
 415                         changed |= IEEE80211_RC_BW_CHANGED;
 416                 sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
 417         }
 418
 419         if (insert)
 420                 rate_control_rate_init(sta);
 421         else
 422                 rate_control_rate_update(local, sband, sta, changed);
 423 out:
 424         spin_unlock_bh(&sta->plink_lock);
 425 }
 426
 427 static struct sta_info *
 428 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
 429 {
 430         struct sta_info *sta;
 431
 432         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
 433                 return NULL;
 434
 435         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 436         if (!sta)
 437                 return NULL;
 438
 439         sta->plink_state = NL80211_PLINK_LISTEN;
 440         sta->sta.wme = true;
 441
 442         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 443         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 444         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 445
 446         return sta;
 447 }
 448
 449 static struct sta_info *
 450 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
 451                     struct ieee802_11_elems *elems)
 452 {
 453         struct sta_info *sta = NULL;
 454
 455         /* Userspace handles station allocation */
 456         if (sdata->u.mesh.user_mpm ||
 457             sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
 458                 cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 459                                                    elems->ie_start,
 460                                                    elems->total_len,
 461                                                    GFP_KERNEL);
 462         else
 463                 sta = __mesh_sta_info_alloc(sdata, addr);
 464
 465         return sta;
 466 }
 467
 468 /*
 469  * mesh_sta_info_get - return mesh sta info entry for @addr.
 470  *
 471  * @sdata: local meshif
 472  * @addr: peer's address
 473  * @elems: IEs from beacon or mesh peering frame.
 474  *
 475  * Return existing or newly allocated sta_info under RCU read lock.
 476  * (re)initialize with given IEs.
 477  */
 478 static struct sta_info *
 479 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
 480                   u8 *addr, struct ieee802_11_elems *elems) __acquires(RCU)
 481 {
 482         struct sta_info *sta = NULL;
 483
 484         rcu_read_lock();
 485         sta = sta_info_get(sdata, addr);
 486         if (sta) {
 487                 mesh_sta_info_init(sdata, sta, elems, false);
 488         } else {
 489                 rcu_read_unlock();
 490                 /* can't run atomic */
 491                 sta = mesh_sta_info_alloc(sdata, addr, elems);
 492                 if (!sta) {
 493                         rcu_read_lock();
 494                         return NULL;
 495                 }
 496
 497                 mesh_sta_info_init(sdata, sta, elems, true);
 498
 499                 if (sta_info_insert_rcu(sta))
 500                         return NULL;
 501         }
 502
 503         return sta;
 504 }
 505
 506 /*
 507  * mesh_neighbour_update - update or initialize new mesh neighbor.
 508  *
 509  * @sdata: local meshif
 510  * @addr: peer's address
 511  * @elems: IEs from beacon or mesh peering frame
 512  *
 513  * Initiates peering if appropriate.
 514  */
 515 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 516                            u8 *hw_addr,
 517                            struct ieee802_11_elems *elems)
 518 {
 519         struct sta_info *sta;
 520         u32 changed = 0;
 521
 522         sta = mesh_sta_info_get(sdata, hw_addr, elems);
 523         if (!sta)
 524                 goto out;
 525
 526         if (mesh_peer_accepts_plinks(elems) &&
 527             sta->plink_state == NL80211_PLINK_LISTEN &&
 528             sdata->u.mesh.accepting_plinks &&
 529             sdata->u.mesh.mshcfg.auto_open_plinks &&
 530             rssi_threshold_check(sdata, sta))
 531                 changed = mesh_plink_open(sta);
 532
 533         ieee80211_mps_frame_release(sta, elems);
 534 out:
 535         rcu_read_unlock();
 536         ieee80211_mbss_info_change_notify(sdata, changed);
 537 }
 538
 539 static void mesh_plink_timer(unsigned long data)
 540 {
 541         struct sta_info *sta;
 542         u16 reason = 0;
 543         struct ieee80211_sub_if_data *sdata;
 544         struct mesh_config *mshcfg;
 545         enum ieee80211_self_protected_actioncode action = 0;
 546
 547         /*
 548          * This STA is valid because sta_info_destroy() will
 549          * del_timer_sync() this timer after having made sure
 550          * it cannot be readded (by deleting the plink.)
 551          */
 552         sta = (struct sta_info *) data;
 553
 554         if (sta->sdata->local->quiescing)
 555                 return;
 556
 557         spin_lock_bh(&sta->plink_lock);
 558
 559         /* If a timer fires just before a state transition on another CPU,
 560          * we may have already extended the timeout and changed state by the
 561          * time we've acquired the lock and arrived  here.  In that case,
 562          * skip this timer and wait for the new one.
 563          */
 564         if (time_before(jiffies, sta->plink_timer.expires)) {
 565                 mpl_dbg(sta->sdata,
 566                         "Ignoring timer for %pM in state %s (timer adjusted)",
 567                         sta->sta.addr, mplstates[sta->plink_state]);
 568                 spin_unlock_bh(&sta->plink_lock);
 569                 return;
 570         }
 571
 572         /* del_timer() and handler may race when entering these states */
 573         if (sta->plink_state == NL80211_PLINK_LISTEN ||
 574             sta->plink_state == NL80211_PLINK_ESTAB) {
 575                 mpl_dbg(sta->sdata,
 576                         "Ignoring timer for %pM in state %s (timer deleted)",
 577                         sta->sta.addr, mplstates[sta->plink_state]);
 578                 spin_unlock_bh(&sta->plink_lock);
 579                 return;
 580         }
 581
 582         mpl_dbg(sta->sdata,
 583                 "Mesh plink timer for %pM fired on state %s\n",
 584                 sta->sta.addr, mplstates[sta->plink_state]);
 585         sdata = sta->sdata;
 586         mshcfg = &sdata->u.mesh.mshcfg;
 587
 588         switch (sta->plink_state) {
 589         case NL80211_PLINK_OPN_RCVD:
 590         case NL80211_PLINK_OPN_SNT:
 591                 /* retry timer */
 592                 if (sta->plink_retries < mshcfg->dot11MeshMaxRetries) {
 593                         u32 rand;
 594                         mpl_dbg(sta->sdata,
 595                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 596                                 sta->sta.addr, sta->plink_retries,
 597                                 sta->plink_timeout);
 598                         get_random_bytes(&rand, sizeof(u32));
 599                         sta->plink_timeout = sta->plink_timeout +
 600                                              rand % sta->plink_timeout;
 601                         ++sta->plink_retries;
 602                         mod_plink_timer(sta, sta->plink_timeout);
 603                         action = WLAN_SP_MESH_PEERING_OPEN;
 604                         break;
 605                 }
 606                 reason = WLAN_REASON_MESH_MAX_RETRIES;
 607                 /* fall through on else */
 608         case NL80211_PLINK_CNF_RCVD:
 609                 /* confirm timer */
 610                 if (!reason)
 611                         reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
 612                 sta->plink_state = NL80211_PLINK_HOLDING;
 613                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 614                 action = WLAN_SP_MESH_PEERING_CLOSE;
 615                 break;
 616         case NL80211_PLINK_HOLDING:
 617                 /* holding timer */
 618                 del_timer(&sta->plink_timer);
 619                 mesh_plink_fsm_restart(sta);
 620                 break;
 621         default:
 622                 break;
 623         }
 624         spin_unlock_bh(&sta->plink_lock);
 625         if (action)
 626                 mesh_plink_frame_tx(sdata, action, sta->sta.addr,
 627                                     sta->llid, sta->plid, reason);
 628 }
 629
 630 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
 631 {
 632         sta->plink_timer.expires = jiffies + msecs_to_jiffies(timeout);
 633         sta->plink_timer.data = (unsigned long) sta;
 634         sta->plink_timer.function = mesh_plink_timer;
 635         sta->plink_timeout = timeout;
 636         add_timer(&sta->plink_timer);
 637 }
 638
 639 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
 640                         u16 llid)
 641 {
 642         struct ieee80211_local *local = sdata->local;
 643         bool in_use = false;
 644         struct sta_info *sta;
 645
 646         rcu_read_lock();
 647         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 648                 if (!memcmp(&sta->llid, &llid, sizeof(llid))) {
 649                         in_use = true;
 650                         break;
 651                 }
 652         }
 653         rcu_read_unlock();
 654
 655         return in_use;
 656 }
 657
 658 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 659 {
 660         u16 llid;
 661
 662         do {
 663                 get_random_bytes(&llid, sizeof(llid));
 664                 /* for mesh PS we still only have the AID range for TIM bits */
 665                 llid = (llid % IEEE80211_MAX_AID) + 1;
 666         } while (llid_in_use(sdata, llid));
 667
 668         return llid;
 669 }
 670
 671 u32 mesh_plink_open(struct sta_info *sta)
 672 {
 673         struct ieee80211_sub_if_data *sdata = sta->sdata;
 674         u32 changed;
 675
 676         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 677                 return 0;
 678
 679         spin_lock_bh(&sta->plink_lock);
 680         sta->llid = mesh_get_new_llid(sdata);
 681         if (sta->plink_state != NL80211_PLINK_LISTEN &&
 682             sta->plink_state != NL80211_PLINK_BLOCKED) {
 683                 spin_unlock_bh(&sta->plink_lock);
 684                 return 0;
 685         }
 686         sta->plink_state = NL80211_PLINK_OPN_SNT;
 687         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 688         spin_unlock_bh(&sta->plink_lock);
 689         mpl_dbg(sdata,
 690                 "Mesh plink: starting establishment with %pM\n",
 691                 sta->sta.addr);
 692
 693         /* set the non-peer mode to active during peering */
 694         changed = ieee80211_mps_local_status_update(sdata);
 695
 696         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 697                             sta->sta.addr, sta->llid, 0, 0);
 698         return changed;
 699 }
 700
 701 u32 mesh_plink_block(struct sta_info *sta)
 702 {
 703         u32 changed;
 704
 705         spin_lock_bh(&sta->plink_lock);
 706         changed = __mesh_plink_deactivate(sta);
 707         sta->plink_state = NL80211_PLINK_BLOCKED;
 708         spin_unlock_bh(&sta->plink_lock);
 709
 710         return changed;
 711 }
 712
 713 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
 714                              struct sta_info *sta,
 715                              enum plink_event event)
 716 {
 717         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 718
 719         u16 reason = (event == CLS_ACPT) ?
 720                      WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
 721
 722         sta->reason = reason;
 723         sta->plink_state = NL80211_PLINK_HOLDING;
 724         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 725 }
 726
 727 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
 728                                 struct sta_info *sta)
 729 {
 730         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 731         u32 changed = 0;
 732
 733         del_timer(&sta->plink_timer);
 734         sta->plink_state = NL80211_PLINK_ESTAB;
 735         changed |= mesh_plink_inc_estab_count(sdata);
 736         changed |= mesh_set_ht_prot_mode(sdata);
 737         changed |= mesh_set_short_slot_time(sdata);
 738         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
 739         ieee80211_mps_sta_status_update(sta);
 740         changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
 741         return changed;
 742 }
 743
 744 /**
 745  * mesh_plink_fsm - step @sta MPM based on @event
 746  *
 747  * @sdata: interface
 748  * @sta: mesh neighbor
 749  * @event: peering event
 750  *
 751  * Return: changed MBSS flags
 752  */
 753 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
 754                           struct sta_info *sta, enum plink_event event)
 755 {
 756         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 757         enum ieee80211_self_protected_actioncode action = 0;
 758         u32 changed = 0;
 759
 760         mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
 761                 mplstates[sta->plink_state], mplevents[event]);
 762
 763         spin_lock_bh(&sta->plink_lock);
 764         switch (sta->plink_state) {
 765         case NL80211_PLINK_LISTEN:
 766                 switch (event) {
 767                 case CLS_ACPT:
 768                         mesh_plink_fsm_restart(sta);
 769                         break;
 770                 case OPN_ACPT:
 771                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 772                         sta->llid = mesh_get_new_llid(sdata);
 773                         mesh_plink_timer_set(sta,
 774                                              mshcfg->dot11MeshRetryTimeout);
 775
 776                         /* set the non-peer mode to active during peering */
 777                         changed |= ieee80211_mps_local_status_update(sdata);
 778                         action = WLAN_SP_MESH_PEERING_OPEN;
 779                         break;
 780                 default:
 781                         break;
 782                 }
 783                 break;
 784         case NL80211_PLINK_OPN_SNT:
 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                         /* retry timer is left untouched */
 794                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 795                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 796                         break;
 797                 case CNF_ACPT:
 798                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 799                         mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
 800                         break;
 801                 default:
 802                         break;
 803                 }
 804                 break;
 805         case NL80211_PLINK_OPN_RCVD:
 806                 switch (event) {
 807                 case OPN_RJCT:
 808                 case CNF_RJCT:
 809                 case CLS_ACPT:
 810                         mesh_plink_close(sdata, sta, event);
 811                         action = WLAN_SP_MESH_PEERING_CLOSE;
 812                         break;
 813                 case OPN_ACPT:
 814                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 815                         break;
 816                 case CNF_ACPT:
 817                         changed |= mesh_plink_establish(sdata, sta);
 818                         break;
 819                 default:
 820                         break;
 821                 }
 822                 break;
 823         case NL80211_PLINK_CNF_RCVD:
 824                 switch (event) {
 825                 case OPN_RJCT:
 826                 case CNF_RJCT:
 827                 case CLS_ACPT:
 828                         mesh_plink_close(sdata, sta, event);
 829                         action = WLAN_SP_MESH_PEERING_CLOSE;
 830                         break;
 831                 case OPN_ACPT:
 832                         changed |= mesh_plink_establish(sdata, sta);
 833                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 834                         break;
 835                 default:
 836                         break;
 837                 }
 838                 break;
 839         case NL80211_PLINK_ESTAB:
 840                 switch (event) {
 841                 case CLS_ACPT:
 842                         changed |= __mesh_plink_deactivate(sta);
 843                         changed |= mesh_set_ht_prot_mode(sdata);
 844                         changed |= mesh_set_short_slot_time(sdata);
 845                         mesh_plink_close(sdata, sta, event);
 846                         action = WLAN_SP_MESH_PEERING_CLOSE;
 847                         break;
 848                 case OPN_ACPT:
 849                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 850                         break;
 851                 default:
 852                         break;
 853                 }
 854                 break;
 855         case NL80211_PLINK_HOLDING:
 856                 switch (event) {
 857                 case CLS_ACPT:
 858                         del_timer(&sta->plink_timer);
 859                         mesh_plink_fsm_restart(sta);
 860                         break;
 861                 case OPN_ACPT:
 862                 case CNF_ACPT:
 863                 case OPN_RJCT:
 864                 case CNF_RJCT:
 865                         action = WLAN_SP_MESH_PEERING_CLOSE;
 866                         break;
 867                 default:
 868                         break;
 869                 }
 870                 break;
 871         default:
 872                 /* should not get here, PLINK_BLOCKED is dealt with at the
 873                  * beginning of the function
 874                  */
 875                 break;
 876         }
 877         spin_unlock_bh(&sta->plink_lock);
 878         if (action) {
 879                 mesh_plink_frame_tx(sdata, action, sta->sta.addr,
 880                                     sta->llid, sta->plid, sta->reason);
 881
 882                 /* also send confirm in open case */
 883                 if (action == WLAN_SP_MESH_PEERING_OPEN) {
 884                         mesh_plink_frame_tx(sdata,
 885                                             WLAN_SP_MESH_PEERING_CONFIRM,
 886                                             sta->sta.addr, sta->llid,
 887                                             sta->plid, 0);
 888                 }
 889         }
 890
 891         return changed;
 892 }
 893
 894 /*
 895  * mesh_plink_get_event - get correct MPM event
 896  *
 897  * @sdata: interface
 898  * @sta: peer, leave NULL if processing a frame from a new suitable peer
 899  * @elems: peering management IEs
 900  * @ftype: frame type
 901  * @llid: peer's peer link ID
 902  * @plid: peer's local link ID
 903  *
 904  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
 905  * an error.
 906  */
 907 static enum plink_event
 908 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
 909                      struct sta_info *sta,
 910                      struct ieee802_11_elems *elems,
 911                      enum ieee80211_self_protected_actioncode ftype,
 912                      u16 llid, u16 plid)
 913 {
 914         enum plink_event event = PLINK_UNDEFINED;
 915         u8 ie_len = elems->peering_len;
 916         bool matches_local;
 917
 918         matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
 919                          mesh_matches_local(sdata, elems));
 920
 921         /* deny open request from non-matching peer */
 922         if (!matches_local && !sta) {
 923                 event = OPN_RJCT;
 924                 goto out;
 925         }
 926
 927         if (!sta) {
 928                 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
 929                         mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 930                         goto out;
 931                 }
 932                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 933                 if (!mesh_plink_free_count(sdata)) {
 934                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 935                         goto out;
 936                 }
 937         } else {
 938                 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
 939                         mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 940                         goto out;
 941                 }
 942                 if (sta->plink_state == NL80211_PLINK_BLOCKED)
 943                         goto out;
 944         }
 945
 946         /* new matching peer */
 947         if (!sta) {
 948                 event = OPN_ACPT;
 949                 goto out;
 950         }
 951
 952         switch (ftype) {
 953         case WLAN_SP_MESH_PEERING_OPEN:
 954                 if (!matches_local)
 955                         event = OPN_RJCT;
 956                 if (!mesh_plink_free_count(sdata) ||
 957                     (sta->plid && sta->plid != plid))
 958                         event = OPN_IGNR;
 959                 else
 960                         event = OPN_ACPT;
 961                 break;
 962         case WLAN_SP_MESH_PEERING_CONFIRM:
 963                 if (!matches_local)
 964                         event = CNF_RJCT;
 965                 if (!mesh_plink_free_count(sdata) ||
 966                     sta->llid != llid ||
 967                     (sta->plid && sta->plid != plid))
 968                         event = CNF_IGNR;
 969                 else
 970                         event = CNF_ACPT;
 971                 break;
 972         case WLAN_SP_MESH_PEERING_CLOSE:
 973                 if (sta->plink_state == NL80211_PLINK_ESTAB)
 974                         /* Do not check for llid or plid. This does not
 975                          * follow the standard but since multiple plinks
 976                          * per sta are not supported, it is necessary in
 977                          * order to avoid a livelock when MP A sees an
 978                          * establish peer link to MP B but MP B does not
 979                          * see it. This can be caused by a timeout in
 980                          * B's peer link establishment or B beign
 981                          * restarted.
 982                          */
 983                         event = CLS_ACPT;
 984                 else if (sta->plid != plid)
 985                         event = CLS_IGNR;
 986                 else if (ie_len == 8 && sta->llid != llid)
 987                         event = CLS_IGNR;
 988                 else
 989                         event = CLS_ACPT;
 990                 break;
 991         default:
 992                 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 993                 break;
 994         }
 995
 996 out:
 997         return event;
 998 }
 999
1000 static void
1001 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1002                          struct ieee80211_mgmt *mgmt,
1003                          struct ieee802_11_elems *elems)
1004 {
1005
1006         struct sta_info *sta;
1007         enum plink_event event;
1008         enum ieee80211_self_protected_actioncode ftype;
1009         u32 changed = 0;
1010         u8 ie_len = elems->peering_len;
1011         u16 plid, llid = 0;
1012
1013         if (!elems->peering) {
1014                 mpl_dbg(sdata,
1015                         "Mesh plink: missing necessary peer link ie\n");
1016                 return;
1017         }
1018
1019         if (elems->rsn_len &&
1020             sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1021                 mpl_dbg(sdata,
1022                         "Mesh plink: can't establish link with secure peer\n");
1023                 return;
1024         }
1025
1026         ftype = mgmt->u.action.u.self_prot.action_code;
1027         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1028             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1029             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1030                                                         && ie_len != 8)) {
1031                 mpl_dbg(sdata,
1032                         "Mesh plink: incorrect plink ie length %d %d\n",
1033                         ftype, ie_len);
1034                 return;
1035         }
1036
1037         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1038             (!elems->mesh_id || !elems->mesh_config)) {
1039                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1040                 return;
1041         }
1042         /* Note the lines below are correct, the llid in the frame is the plid
1043          * from the point of view of this host.
1044          */
1045         plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1046         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1047             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1048                 llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1049
1050         /* WARNING: Only for sta pointer, is dropped & re-acquired */
1051         rcu_read_lock();
1052
1053         sta = sta_info_get(sdata, mgmt->sa);
1054
1055         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1056             !rssi_threshold_check(sdata, sta)) {
1057                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1058                         mgmt->sa);
1059                 goto unlock_rcu;
1060         }
1061
1062         /* Now we will figure out the appropriate event... */
1063         event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1064
1065         if (event == OPN_ACPT) {
1066                 rcu_read_unlock();
1067                 /* allocate sta entry if necessary and update info */
1068                 sta = mesh_sta_info_get(sdata, mgmt->sa, elems);
1069                 if (!sta) {
1070                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1071                         goto unlock_rcu;
1072                 }
1073                 sta->plid = plid;
1074         } else if (!sta && event == OPN_RJCT) {
1075                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
1076                                     mgmt->sa, 0, plid,
1077                                     WLAN_REASON_MESH_CONFIG);
1078                 goto unlock_rcu;
1079         } else if (!sta || event == PLINK_UNDEFINED) {
1080                 /* something went wrong */
1081                 goto unlock_rcu;
1082         }
1083
1084         /* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1085         if (!sta->plid && event == CNF_ACPT)
1086                 sta->plid = plid;
1087
1088         changed |= mesh_plink_fsm(sdata, sta, event);
1089
1090 unlock_rcu:
1091         rcu_read_unlock();
1092
1093         if (changed)
1094                 ieee80211_mbss_info_change_notify(sdata, changed);
1095 }
1096
1097 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1098                          struct ieee80211_mgmt *mgmt, size_t len,
1099                          struct ieee80211_rx_status *rx_status)
1100 {
1101         struct ieee802_11_elems elems;
1102         size_t baselen;
1103         u8 *baseaddr;
1104
1105         /* need action_code, aux */
1106         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1107                 return;
1108
1109         if (sdata->u.mesh.user_mpm)
1110                 /* userspace must register for these */
1111                 return;
1112
1113         if (is_multicast_ether_addr(mgmt->da)) {
1114                 mpl_dbg(sdata,
1115                         "Mesh plink: ignore frame from multicast address\n");
1116                 return;
1117         }
1118
1119         baseaddr = mgmt->u.action.u.self_prot.variable;
1120         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1121         if (mgmt->u.action.u.self_prot.action_code ==
1122                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
1123                 baseaddr += 4;
1124                 baselen += 4;
1125
1126                 if (baselen > len)
1127                         return;
1128         }
1129         ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems);
1130         mesh_process_plink_frame(sdata, mgmt, &elems);
1131 }