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_CNF_AID(mgmt) ((mgmt)->u.action.u.self_prot.variable + 2)
  17 #define PLINK_GET_LLID(p) (p + 2)
  18 #define PLINK_GET_PLID(p) (p + 4)
  19
  20 #define mod_plink_timer(s, t) (mod_timer(&s->mesh->plink_timer, \
  21                                 jiffies + msecs_to_jiffies(t)))
  22
  23 enum plink_event {
  24         PLINK_UNDEFINED,
  25         OPN_ACPT,
  26         OPN_RJCT,
  27         OPN_IGNR,
  28         CNF_ACPT,
  29         CNF_RJCT,
  30         CNF_IGNR,
  31         CLS_ACPT,
  32         CLS_IGNR
  33 };
  34
  35 static const char * const mplstates[] = {
  36         [NL80211_PLINK_LISTEN] = "LISTEN",
  37         [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
  38         [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
  39         [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
  40         [NL80211_PLINK_ESTAB] = "ESTAB",
  41         [NL80211_PLINK_HOLDING] = "HOLDING",
  42         [NL80211_PLINK_BLOCKED] = "BLOCKED"
  43 };
  44
  45 static const char * const mplevents[] = {
  46         [PLINK_UNDEFINED] = "NONE",
  47         [OPN_ACPT] = "OPN_ACPT",
  48         [OPN_RJCT] = "OPN_RJCT",
  49         [OPN_IGNR] = "OPN_IGNR",
  50         [CNF_ACPT] = "CNF_ACPT",
  51         [CNF_RJCT] = "CNF_RJCT",
  52         [CNF_IGNR] = "CNF_IGNR",
  53         [CLS_ACPT] = "CLS_ACPT",
  54         [CLS_IGNR] = "CLS_IGNR"
  55 };
  56
  57 /* We only need a valid sta if user configured a minimum rssi_threshold. */
  58 static bool rssi_threshold_check(struct ieee80211_sub_if_data *sdata,
  59                                  struct sta_info *sta)
  60 {
  61         s32 rssi_threshold = sdata->u.mesh.mshcfg.rssi_threshold;
  62         return rssi_threshold == 0 ||
  63                (sta && (s8) -ewma_signal_read(&sta->avg_signal) > rssi_threshold);
  64 }
  65
  66 /**
  67  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  68  *
  69  * @sta: mesh peer link to restart
  70  *
  71  * Locking: this function must be called holding sta->mesh->plink_lock
  72  */
  73 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  74 {
  75         lockdep_assert_held(&sta->mesh->plink_lock);
  76         sta->mesh->plink_state = NL80211_PLINK_LISTEN;
  77         sta->mesh->llid = sta->mesh->plid = sta->mesh->reason = 0;
  78         sta->mesh->plink_retries = 0;
  79 }
  80
  81 /*
  82  * mesh_set_short_slot_time - enable / disable ERP short slot time.
  83  *
  84  * The standard indirectly mandates mesh STAs to turn off short slot time by
  85  * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
  86  * can't be sneaky about it. Enable short slot time if all mesh STAs in the
  87  * MBSS support ERP rates.
  88  *
  89  * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
  90  */
  91 static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
  92 {
  93         struct ieee80211_local *local = sdata->local;
  94         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
  95         struct ieee80211_supported_band *sband = local->hw.wiphy->bands[band];
  96         struct sta_info *sta;
  97         u32 erp_rates = 0, changed = 0;
  98         int i;
  99         bool short_slot = false;
 100
 101         if (band == IEEE80211_BAND_5GHZ) {
 102                 /* (IEEE 802.11-2012 19.4.5) */
 103                 short_slot = true;
 104                 goto out;
 105         } else if (band != IEEE80211_BAND_2GHZ)
 106                 goto out;
 107
 108         for (i = 0; i < sband->n_bitrates; i++)
 109                 if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
 110                         erp_rates |= BIT(i);
 111
 112         if (!erp_rates)
 113                 goto out;
 114
 115         rcu_read_lock();
 116         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 117                 if (sdata != sta->sdata ||
 118                     sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 119                         continue;
 120
 121                 short_slot = false;
 122                 if (erp_rates & sta->sta.supp_rates[band])
 123                         short_slot = true;
 124                  else
 125                         break;
 126         }
 127         rcu_read_unlock();
 128
 129 out:
 130         if (sdata->vif.bss_conf.use_short_slot != short_slot) {
 131                 sdata->vif.bss_conf.use_short_slot = short_slot;
 132                 changed = BSS_CHANGED_ERP_SLOT;
 133                 mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
 134                         sdata->vif.addr, short_slot);
 135         }
 136         return changed;
 137 }
 138
 139 /**
 140  * mesh_set_ht_prot_mode - set correct HT protection mode
 141  *
 142  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 143  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 144  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 145  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 146  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 147  * HT20 peer is present. Otherwise no-protection mode is selected.
 148  */
 149 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 150 {
 151         struct ieee80211_local *local = sdata->local;
 152         struct sta_info *sta;
 153         u16 ht_opmode;
 154         bool non_ht_sta = false, ht20_sta = false;
 155
 156         switch (sdata->vif.bss_conf.chandef.width) {
 157         case NL80211_CHAN_WIDTH_20_NOHT:
 158         case NL80211_CHAN_WIDTH_5:
 159         case NL80211_CHAN_WIDTH_10:
 160                 return 0;
 161         default:
 162                 break;
 163         }
 164
 165         rcu_read_lock();
 166         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 167                 if (sdata != sta->sdata ||
 168                     sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 169                         continue;
 170
 171                 if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
 172                         continue;
 173
 174                 if (!sta->sta.ht_cap.ht_supported) {
 175                         mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
 176                                        sta->sta.addr);
 177                         non_ht_sta = true;
 178                         break;
 179                 }
 180
 181                 mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
 182                 ht20_sta = true;
 183         }
 184         rcu_read_unlock();
 185
 186         if (non_ht_sta)
 187                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 188         else if (ht20_sta &&
 189                  sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
 190                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 191         else
 192                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 193
 194         if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
 195                 return 0;
 196
 197         sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 198         sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 199         mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
 200         return BSS_CHANGED_HT;
 201 }
 202
 203 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 204                                struct sta_info *sta,
 205                                enum ieee80211_self_protected_actioncode action,
 206                                u8 *da, u16 llid, u16 plid, u16 reason)
 207 {
 208         struct ieee80211_local *local = sdata->local;
 209         struct sk_buff *skb;
 210         struct ieee80211_tx_info *info;
 211         struct ieee80211_mgmt *mgmt;
 212         bool include_plid = false;
 213         u16 peering_proto = 0;
 214         u8 *pos, ie_len = 4;
 215         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 216                       sizeof(mgmt->u.action.u.self_prot);
 217         int err = -ENOMEM;
 218
 219         skb = dev_alloc_skb(local->tx_headroom +
 220                             hdr_len +
 221                             2 + /* capability info */
 222                             2 + /* AID */
 223                             2 + 8 + /* supported rates */
 224                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 225                             2 + sdata->u.mesh.mesh_id_len +
 226                             2 + sizeof(struct ieee80211_meshconf_ie) +
 227                             2 + sizeof(struct ieee80211_ht_cap) +
 228                             2 + sizeof(struct ieee80211_ht_operation) +
 229                             2 + 8 + /* peering IE */
 230                             sdata->u.mesh.ie_len);
 231         if (!skb)
 232                 return err;
 233         info = IEEE80211_SKB_CB(skb);
 234         skb_reserve(skb, local->tx_headroom);
 235         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 236         memset(mgmt, 0, hdr_len);
 237         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 238                                           IEEE80211_STYPE_ACTION);
 239         memcpy(mgmt->da, da, ETH_ALEN);
 240         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 241         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 242         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 243         mgmt->u.action.u.self_prot.action_code = action;
 244
 245         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 246                 enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 247
 248                 /* capability info */
 249                 pos = skb_put(skb, 2);
 250                 memset(pos, 0, 2);
 251                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 252                         /* AID */
 253                         pos = skb_put(skb, 2);
 254                         put_unaligned_le16(sta->sta.aid, pos);
 255                 }
 256                 if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
 257                     ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
 258                     mesh_add_rsn_ie(sdata, skb) ||
 259                     mesh_add_meshid_ie(sdata, skb) ||
 260                     mesh_add_meshconf_ie(sdata, skb))
 261                         goto free;
 262         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 263                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
 264                 if (mesh_add_meshid_ie(sdata, skb))
 265                         goto free;
 266         }
 267
 268         /* Add Mesh Peering Management element */
 269         switch (action) {
 270         case WLAN_SP_MESH_PEERING_OPEN:
 271                 break;
 272         case WLAN_SP_MESH_PEERING_CONFIRM:
 273                 ie_len += 2;
 274                 include_plid = true;
 275                 break;
 276         case WLAN_SP_MESH_PEERING_CLOSE:
 277                 if (plid) {
 278                         ie_len += 2;
 279                         include_plid = true;
 280                 }
 281                 ie_len += 2;    /* reason code */
 282                 break;
 283         default:
 284                 err = -EINVAL;
 285                 goto free;
 286         }
 287
 288         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 289                 goto free;
 290
 291         pos = skb_put(skb, 2 + ie_len);
 292         *pos++ = WLAN_EID_PEER_MGMT;
 293         *pos++ = ie_len;
 294         memcpy(pos, &peering_proto, 2);
 295         pos += 2;
 296         put_unaligned_le16(llid, pos);
 297         pos += 2;
 298         if (include_plid) {
 299                 put_unaligned_le16(plid, pos);
 300                 pos += 2;
 301         }
 302         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 303                 put_unaligned_le16(reason, pos);
 304                 pos += 2;
 305         }
 306
 307         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 308                 if (mesh_add_ht_cap_ie(sdata, skb) ||
 309                     mesh_add_ht_oper_ie(sdata, skb))
 310                         goto free;
 311         }
 312
 313         if (mesh_add_vendor_ies(sdata, skb))
 314                 goto free;
 315
 316         ieee80211_tx_skb(sdata, skb);
 317         return 0;
 318 free:
 319         kfree_skb(skb);
 320         return err;
 321 }
 322
 323 /**
 324  * __mesh_plink_deactivate - deactivate mesh peer link
 325  *
 326  * @sta: mesh peer link to deactivate
 327  *
 328  * All mesh paths with this peer as next hop will be flushed
 329  * Returns beacon changed flag if the beacon content changed.
 330  *
 331  * Locking: the caller must hold sta->mesh->plink_lock
 332  */
 333 static u32 __mesh_plink_deactivate(struct sta_info *sta)
 334 {
 335         struct ieee80211_sub_if_data *sdata = sta->sdata;
 336         u32 changed = 0;
 337
 338         lockdep_assert_held(&sta->mesh->plink_lock);
 339
 340         if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
 341                 changed = mesh_plink_dec_estab_count(sdata);
 342         sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 343         mesh_path_flush_by_nexthop(sta);
 344
 345         ieee80211_mps_sta_status_update(sta);
 346         changed |= ieee80211_mps_set_sta_local_pm(sta,
 347                         NL80211_MESH_POWER_UNKNOWN);
 348
 349         return changed;
 350 }
 351
 352 /**
 353  * mesh_plink_deactivate - deactivate mesh peer link
 354  *
 355  * @sta: mesh peer link to deactivate
 356  *
 357  * All mesh paths with this peer as next hop will be flushed
 358  */
 359 u32 mesh_plink_deactivate(struct sta_info *sta)
 360 {
 361         struct ieee80211_sub_if_data *sdata = sta->sdata;
 362         u32 changed;
 363
 364         spin_lock_bh(&sta->mesh->plink_lock);
 365         changed = __mesh_plink_deactivate(sta);
 366         sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
 367         mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
 368                             sta->sta.addr, sta->mesh->llid, sta->mesh->plid,
 369                             sta->mesh->reason);
 370         spin_unlock_bh(&sta->mesh->plink_lock);
 371
 372         return changed;
 373 }
 374
 375 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
 376                                struct sta_info *sta,
 377                                struct ieee802_11_elems *elems, bool insert)
 378 {
 379         struct ieee80211_local *local = sdata->local;
 380         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 381         struct ieee80211_supported_band *sband;
 382         u32 rates, basic_rates = 0, changed = 0;
 383         enum ieee80211_sta_rx_bandwidth bw = sta->sta.bandwidth;
 384
 385         sband = local->hw.wiphy->bands[band];
 386         rates = ieee80211_sta_get_rates(sdata, elems, band, &basic_rates);
 387
 388         spin_lock_bh(&sta->mesh->plink_lock);
 389         sta->last_rx = jiffies;
 390
 391         /* rates and capabilities don't change during peering */
 392         if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
 393             sta->mesh->processed_beacon)
 394                 goto out;
 395         sta->mesh->processed_beacon = true;
 396
 397         if (sta->sta.supp_rates[band] != rates)
 398                 changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
 399         sta->sta.supp_rates[band] = rates;
 400
 401         if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 402                                               elems->ht_cap_elem, sta))
 403                 changed |= IEEE80211_RC_BW_CHANGED;
 404
 405         if (bw != sta->sta.bandwidth)
 406                 changed |= IEEE80211_RC_BW_CHANGED;
 407
 408         /* HT peer is operating 20MHz-only */
 409         if (elems->ht_operation &&
 410             !(elems->ht_operation->ht_param &
 411               IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
 412                 if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
 413                         changed |= IEEE80211_RC_BW_CHANGED;
 414                 sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
 415         }
 416
 417         if (insert)
 418                 rate_control_rate_init(sta);
 419         else
 420                 rate_control_rate_update(local, sband, sta, changed);
 421 out:
 422         spin_unlock_bh(&sta->mesh->plink_lock);
 423 }
 424
 425 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
 426 {
 427         struct sta_info *sta;
 428         unsigned long *aid_map;
 429         int aid;
 430
 431         aid_map = kcalloc(BITS_TO_LONGS(IEEE80211_MAX_AID + 1),
 432                           sizeof(*aid_map), GFP_KERNEL);
 433         if (!aid_map)
 434                 return -ENOMEM;
 435
 436         /* reserve aid 0 for mcast indication */
 437         __set_bit(0, aid_map);
 438
 439         rcu_read_lock();
 440         list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
 441                 __set_bit(sta->sta.aid, aid_map);
 442         rcu_read_unlock();
 443
 444         aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
 445         kfree(aid_map);
 446
 447         if (aid > IEEE80211_MAX_AID)
 448                 return -ENOBUFS;
 449
 450         return aid;
 451 }
 452
 453 static struct sta_info *
 454 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
 455 {
 456         struct sta_info *sta;
 457         int aid;
 458
 459         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
 460                 return NULL;
 461
 462         aid = mesh_allocate_aid(sdata);
 463         if (aid < 0)
 464                 return NULL;
 465
 466         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 467         if (!sta)
 468                 return NULL;
 469
 470         sta->mesh->plink_state = NL80211_PLINK_LISTEN;
 471         sta->sta.wme = true;
 472         sta->sta.aid = aid;
 473
 474         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 475         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 476         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 477
 478         return sta;
 479 }
 480
 481 static struct sta_info *
 482 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
 483                     struct ieee802_11_elems *elems)
 484 {
 485         struct sta_info *sta = NULL;
 486
 487         /* Userspace handles station allocation */
 488         if (sdata->u.mesh.user_mpm ||
 489             sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
 490                 cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 491                                                    elems->ie_start,
 492                                                    elems->total_len,
 493                                                    GFP_KERNEL);
 494         else
 495                 sta = __mesh_sta_info_alloc(sdata, addr);
 496
 497         return sta;
 498 }
 499
 500 /*
 501  * mesh_sta_info_get - return mesh sta info entry for @addr.
 502  *
 503  * @sdata: local meshif
 504  * @addr: peer's address
 505  * @elems: IEs from beacon or mesh peering frame.
 506  *
 507  * Return existing or newly allocated sta_info under RCU read lock.
 508  * (re)initialize with given IEs.
 509  */
 510 static struct sta_info *
 511 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
 512                   u8 *addr, struct ieee802_11_elems *elems) __acquires(RCU)
 513 {
 514         struct sta_info *sta = NULL;
 515
 516         rcu_read_lock();
 517         sta = sta_info_get(sdata, addr);
 518         if (sta) {
 519                 mesh_sta_info_init(sdata, sta, elems, false);
 520         } else {
 521                 rcu_read_unlock();
 522                 /* can't run atomic */
 523                 sta = mesh_sta_info_alloc(sdata, addr, elems);
 524                 if (!sta) {
 525                         rcu_read_lock();
 526                         return NULL;
 527                 }
 528
 529                 mesh_sta_info_init(sdata, sta, elems, true);
 530
 531                 if (sta_info_insert_rcu(sta))
 532                         return NULL;
 533         }
 534
 535         return sta;
 536 }
 537
 538 /*
 539  * mesh_neighbour_update - update or initialize new mesh neighbor.
 540  *
 541  * @sdata: local meshif
 542  * @addr: peer's address
 543  * @elems: IEs from beacon or mesh peering frame
 544  *
 545  * Initiates peering if appropriate.
 546  */
 547 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 548                            u8 *hw_addr,
 549                            struct ieee802_11_elems *elems)
 550 {
 551         struct sta_info *sta;
 552         u32 changed = 0;
 553
 554         sta = mesh_sta_info_get(sdata, hw_addr, elems);
 555         if (!sta)
 556                 goto out;
 557
 558         if (mesh_peer_accepts_plinks(elems) &&
 559             sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
 560             sdata->u.mesh.accepting_plinks &&
 561             sdata->u.mesh.mshcfg.auto_open_plinks &&
 562             rssi_threshold_check(sdata, sta))
 563                 changed = mesh_plink_open(sta);
 564
 565         ieee80211_mps_frame_release(sta, elems);
 566 out:
 567         rcu_read_unlock();
 568         ieee80211_mbss_info_change_notify(sdata, changed);
 569 }
 570
 571 static void mesh_plink_timer(unsigned long data)
 572 {
 573         struct sta_info *sta;
 574         u16 reason = 0;
 575         struct ieee80211_sub_if_data *sdata;
 576         struct mesh_config *mshcfg;
 577         enum ieee80211_self_protected_actioncode action = 0;
 578
 579         /*
 580          * This STA is valid because sta_info_destroy() will
 581          * del_timer_sync() this timer after having made sure
 582          * it cannot be readded (by deleting the plink.)
 583          */
 584         sta = (struct sta_info *) data;
 585
 586         if (sta->sdata->local->quiescing)
 587                 return;
 588
 589         spin_lock_bh(&sta->mesh->plink_lock);
 590
 591         /* If a timer fires just before a state transition on another CPU,
 592          * we may have already extended the timeout and changed state by the
 593          * time we've acquired the lock and arrived  here.  In that case,
 594          * skip this timer and wait for the new one.
 595          */
 596         if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
 597                 mpl_dbg(sta->sdata,
 598                         "Ignoring timer for %pM in state %s (timer adjusted)",
 599                         sta->sta.addr, mplstates[sta->mesh->plink_state]);
 600                 spin_unlock_bh(&sta->mesh->plink_lock);
 601                 return;
 602         }
 603
 604         /* del_timer() and handler may race when entering these states */
 605         if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
 606             sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
 607                 mpl_dbg(sta->sdata,
 608                         "Ignoring timer for %pM in state %s (timer deleted)",
 609                         sta->sta.addr, mplstates[sta->mesh->plink_state]);
 610                 spin_unlock_bh(&sta->mesh->plink_lock);
 611                 return;
 612         }
 613
 614         mpl_dbg(sta->sdata,
 615                 "Mesh plink timer for %pM fired on state %s\n",
 616                 sta->sta.addr, mplstates[sta->mesh->plink_state]);
 617         sdata = sta->sdata;
 618         mshcfg = &sdata->u.mesh.mshcfg;
 619
 620         switch (sta->mesh->plink_state) {
 621         case NL80211_PLINK_OPN_RCVD:
 622         case NL80211_PLINK_OPN_SNT:
 623                 /* retry timer */
 624                 if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
 625                         u32 rand;
 626                         mpl_dbg(sta->sdata,
 627                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 628                                 sta->sta.addr, sta->mesh->plink_retries,
 629                                 sta->mesh->plink_timeout);
 630                         get_random_bytes(&rand, sizeof(u32));
 631                         sta->mesh->plink_timeout = sta->mesh->plink_timeout +
 632                                              rand % sta->mesh->plink_timeout;
 633                         ++sta->mesh->plink_retries;
 634                         mod_plink_timer(sta, sta->mesh->plink_timeout);
 635                         action = WLAN_SP_MESH_PEERING_OPEN;
 636                         break;
 637                 }
 638                 reason = WLAN_REASON_MESH_MAX_RETRIES;
 639                 /* fall through on else */
 640         case NL80211_PLINK_CNF_RCVD:
 641                 /* confirm timer */
 642                 if (!reason)
 643                         reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
 644                 sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 645                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 646                 action = WLAN_SP_MESH_PEERING_CLOSE;
 647                 break;
 648         case NL80211_PLINK_HOLDING:
 649                 /* holding timer */
 650                 del_timer(&sta->mesh->plink_timer);
 651                 mesh_plink_fsm_restart(sta);
 652                 break;
 653         default:
 654                 break;
 655         }
 656         spin_unlock_bh(&sta->mesh->plink_lock);
 657         if (action)
 658                 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 659                                     sta->mesh->llid, sta->mesh->plid, reason);
 660 }
 661
 662 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
 663 {
 664         sta->mesh->plink_timer.expires = jiffies + msecs_to_jiffies(timeout);
 665         sta->mesh->plink_timer.data = (unsigned long) sta;
 666         sta->mesh->plink_timer.function = mesh_plink_timer;
 667         sta->mesh->plink_timeout = timeout;
 668         add_timer(&sta->mesh->plink_timer);
 669 }
 670
 671 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
 672                         u16 llid)
 673 {
 674         struct ieee80211_local *local = sdata->local;
 675         bool in_use = false;
 676         struct sta_info *sta;
 677
 678         rcu_read_lock();
 679         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 680                 if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
 681                         in_use = true;
 682                         break;
 683                 }
 684         }
 685         rcu_read_unlock();
 686
 687         return in_use;
 688 }
 689
 690 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 691 {
 692         u16 llid;
 693
 694         do {
 695                 get_random_bytes(&llid, sizeof(llid));
 696         } while (llid_in_use(sdata, llid));
 697
 698         return llid;
 699 }
 700
 701 u32 mesh_plink_open(struct sta_info *sta)
 702 {
 703         struct ieee80211_sub_if_data *sdata = sta->sdata;
 704         u32 changed;
 705
 706         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 707                 return 0;
 708
 709         spin_lock_bh(&sta->mesh->plink_lock);
 710         sta->mesh->llid = mesh_get_new_llid(sdata);
 711         if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
 712             sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
 713                 spin_unlock_bh(&sta->mesh->plink_lock);
 714                 return 0;
 715         }
 716         sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
 717         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 718         spin_unlock_bh(&sta->mesh->plink_lock);
 719         mpl_dbg(sdata,
 720                 "Mesh plink: starting establishment with %pM\n",
 721                 sta->sta.addr);
 722
 723         /* set the non-peer mode to active during peering */
 724         changed = ieee80211_mps_local_status_update(sdata);
 725
 726         mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
 727                             sta->sta.addr, sta->mesh->llid, 0, 0);
 728         return changed;
 729 }
 730
 731 u32 mesh_plink_block(struct sta_info *sta)
 732 {
 733         u32 changed;
 734
 735         spin_lock_bh(&sta->mesh->plink_lock);
 736         changed = __mesh_plink_deactivate(sta);
 737         sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 738         spin_unlock_bh(&sta->mesh->plink_lock);
 739
 740         return changed;
 741 }
 742
 743 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
 744                              struct sta_info *sta,
 745                              enum plink_event event)
 746 {
 747         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 748         u16 reason = (event == CLS_ACPT) ?
 749                      WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
 750
 751         sta->mesh->reason = reason;
 752         sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 753         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 754 }
 755
 756 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
 757                                 struct sta_info *sta)
 758 {
 759         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 760         u32 changed = 0;
 761
 762         del_timer(&sta->mesh->plink_timer);
 763         sta->mesh->plink_state = NL80211_PLINK_ESTAB;
 764         changed |= mesh_plink_inc_estab_count(sdata);
 765         changed |= mesh_set_ht_prot_mode(sdata);
 766         changed |= mesh_set_short_slot_time(sdata);
 767         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
 768         ieee80211_mps_sta_status_update(sta);
 769         changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
 770         return changed;
 771 }
 772
 773 /**
 774  * mesh_plink_fsm - step @sta MPM based on @event
 775  *
 776  * @sdata: interface
 777  * @sta: mesh neighbor
 778  * @event: peering event
 779  *
 780  * Return: changed MBSS flags
 781  */
 782 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
 783                           struct sta_info *sta, enum plink_event event)
 784 {
 785         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 786         enum ieee80211_self_protected_actioncode action = 0;
 787         u32 changed = 0;
 788
 789         mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
 790                 mplstates[sta->mesh->plink_state], mplevents[event]);
 791
 792         spin_lock_bh(&sta->mesh->plink_lock);
 793         switch (sta->mesh->plink_state) {
 794         case NL80211_PLINK_LISTEN:
 795                 switch (event) {
 796                 case CLS_ACPT:
 797                         mesh_plink_fsm_restart(sta);
 798                         break;
 799                 case OPN_ACPT:
 800                         sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 801                         sta->mesh->llid = mesh_get_new_llid(sdata);
 802                         mesh_plink_timer_set(sta,
 803                                              mshcfg->dot11MeshRetryTimeout);
 804
 805                         /* set the non-peer mode to active during peering */
 806                         changed |= ieee80211_mps_local_status_update(sdata);
 807                         action = WLAN_SP_MESH_PEERING_OPEN;
 808                         break;
 809                 default:
 810                         break;
 811                 }
 812                 break;
 813         case NL80211_PLINK_OPN_SNT:
 814                 switch (event) {
 815                 case OPN_RJCT:
 816                 case CNF_RJCT:
 817                 case CLS_ACPT:
 818                         mesh_plink_close(sdata, sta, event);
 819                         action = WLAN_SP_MESH_PEERING_CLOSE;
 820                         break;
 821                 case OPN_ACPT:
 822                         /* retry timer is left untouched */
 823                         sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 824                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 825                         break;
 826                 case CNF_ACPT:
 827                         sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
 828                         mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
 829                         break;
 830                 default:
 831                         break;
 832                 }
 833                 break;
 834         case NL80211_PLINK_OPN_RCVD:
 835                 switch (event) {
 836                 case OPN_RJCT:
 837                 case CNF_RJCT:
 838                 case CLS_ACPT:
 839                         mesh_plink_close(sdata, sta, event);
 840                         action = WLAN_SP_MESH_PEERING_CLOSE;
 841                         break;
 842                 case OPN_ACPT:
 843                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 844                         break;
 845                 case CNF_ACPT:
 846                         changed |= mesh_plink_establish(sdata, sta);
 847                         break;
 848                 default:
 849                         break;
 850                 }
 851                 break;
 852         case NL80211_PLINK_CNF_RCVD:
 853                 switch (event) {
 854                 case OPN_RJCT:
 855                 case CNF_RJCT:
 856                 case CLS_ACPT:
 857                         mesh_plink_close(sdata, sta, event);
 858                         action = WLAN_SP_MESH_PEERING_CLOSE;
 859                         break;
 860                 case OPN_ACPT:
 861                         changed |= mesh_plink_establish(sdata, sta);
 862                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 863                         break;
 864                 default:
 865                         break;
 866                 }
 867                 break;
 868         case NL80211_PLINK_ESTAB:
 869                 switch (event) {
 870                 case CLS_ACPT:
 871                         changed |= __mesh_plink_deactivate(sta);
 872                         changed |= mesh_set_ht_prot_mode(sdata);
 873                         changed |= mesh_set_short_slot_time(sdata);
 874                         mesh_plink_close(sdata, sta, event);
 875                         action = WLAN_SP_MESH_PEERING_CLOSE;
 876                         break;
 877                 case OPN_ACPT:
 878                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 879                         break;
 880                 default:
 881                         break;
 882                 }
 883                 break;
 884         case NL80211_PLINK_HOLDING:
 885                 switch (event) {
 886                 case CLS_ACPT:
 887                         del_timer(&sta->mesh->plink_timer);
 888                         mesh_plink_fsm_restart(sta);
 889                         break;
 890                 case OPN_ACPT:
 891                 case CNF_ACPT:
 892                 case OPN_RJCT:
 893                 case CNF_RJCT:
 894                         action = WLAN_SP_MESH_PEERING_CLOSE;
 895                         break;
 896                 default:
 897                         break;
 898                 }
 899                 break;
 900         default:
 901                 /* should not get here, PLINK_BLOCKED is dealt with at the
 902                  * beginning of the function
 903                  */
 904                 break;
 905         }
 906         spin_unlock_bh(&sta->mesh->plink_lock);
 907         if (action) {
 908                 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 909                                     sta->mesh->llid, sta->mesh->plid,
 910                                     sta->mesh->reason);
 911
 912                 /* also send confirm in open case */
 913                 if (action == WLAN_SP_MESH_PEERING_OPEN) {
 914                         mesh_plink_frame_tx(sdata, sta,
 915                                             WLAN_SP_MESH_PEERING_CONFIRM,
 916                                             sta->sta.addr, sta->mesh->llid,
 917                                             sta->mesh->plid, 0);
 918                 }
 919         }
 920
 921         return changed;
 922 }
 923
 924 /*
 925  * mesh_plink_get_event - get correct MPM event
 926  *
 927  * @sdata: interface
 928  * @sta: peer, leave NULL if processing a frame from a new suitable peer
 929  * @elems: peering management IEs
 930  * @ftype: frame type
 931  * @llid: peer's peer link ID
 932  * @plid: peer's local link ID
 933  *
 934  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
 935  * an error.
 936  */
 937 static enum plink_event
 938 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
 939                      struct sta_info *sta,
 940                      struct ieee802_11_elems *elems,
 941                      enum ieee80211_self_protected_actioncode ftype,
 942                      u16 llid, u16 plid)
 943 {
 944         enum plink_event event = PLINK_UNDEFINED;
 945         u8 ie_len = elems->peering_len;
 946         bool matches_local;
 947
 948         matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
 949                          mesh_matches_local(sdata, elems));
 950
 951         /* deny open request from non-matching peer */
 952         if (!matches_local && !sta) {
 953                 event = OPN_RJCT;
 954                 goto out;
 955         }
 956
 957         if (!sta) {
 958                 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
 959                         mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 960                         goto out;
 961                 }
 962                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 963                 if (!mesh_plink_free_count(sdata)) {
 964                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 965                         goto out;
 966                 }
 967         } else {
 968                 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
 969                         mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 970                         goto out;
 971                 }
 972                 if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
 973                         goto out;
 974         }
 975
 976         /* new matching peer */
 977         if (!sta) {
 978                 event = OPN_ACPT;
 979                 goto out;
 980         }
 981
 982         switch (ftype) {
 983         case WLAN_SP_MESH_PEERING_OPEN:
 984                 if (!matches_local)
 985                         event = OPN_RJCT;
 986                 if (!mesh_plink_free_count(sdata) ||
 987                     (sta->mesh->plid && sta->mesh->plid != plid))
 988                         event = OPN_IGNR;
 989                 else
 990                         event = OPN_ACPT;
 991                 break;
 992         case WLAN_SP_MESH_PEERING_CONFIRM:
 993                 if (!matches_local)
 994                         event = CNF_RJCT;
 995                 if (!mesh_plink_free_count(sdata) ||
 996                     sta->mesh->llid != llid ||
 997                     (sta->mesh->plid && sta->mesh->plid != plid))
 998                         event = CNF_IGNR;
 999                 else
1000                         event = CNF_ACPT;
1001                 break;
1002         case WLAN_SP_MESH_PEERING_CLOSE:
1003                 if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1004                         /* Do not check for llid or plid. This does not
1005                          * follow the standard but since multiple plinks
1006                          * per sta are not supported, it is necessary in
1007                          * order to avoid a livelock when MP A sees an
1008                          * establish peer link to MP B but MP B does not
1009                          * see it. This can be caused by a timeout in
1010                          * B's peer link establishment or B beign
1011                          * restarted.
1012                          */
1013                         event = CLS_ACPT;
1014                 else if (sta->mesh->plid != plid)
1015                         event = CLS_IGNR;
1016                 else if (ie_len == 8 && sta->mesh->llid != llid)
1017                         event = CLS_IGNR;
1018                 else
1019                         event = CLS_ACPT;
1020                 break;
1021         default:
1022                 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1023                 break;
1024         }
1025
1026 out:
1027         return event;
1028 }
1029
1030 static void
1031 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1032                          struct ieee80211_mgmt *mgmt,
1033                          struct ieee802_11_elems *elems)
1034 {
1035
1036         struct sta_info *sta;
1037         enum plink_event event;
1038         enum ieee80211_self_protected_actioncode ftype;
1039         u32 changed = 0;
1040         u8 ie_len = elems->peering_len;
1041         u16 plid, llid = 0;
1042
1043         if (!elems->peering) {
1044                 mpl_dbg(sdata,
1045                         "Mesh plink: missing necessary peer link ie\n");
1046                 return;
1047         }
1048
1049         if (elems->rsn_len &&
1050             sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1051                 mpl_dbg(sdata,
1052                         "Mesh plink: can't establish link with secure peer\n");
1053                 return;
1054         }
1055
1056         ftype = mgmt->u.action.u.self_prot.action_code;
1057         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1058             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1059             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1060                                                         && ie_len != 8)) {
1061                 mpl_dbg(sdata,
1062                         "Mesh plink: incorrect plink ie length %d %d\n",
1063                         ftype, ie_len);
1064                 return;
1065         }
1066
1067         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1068             (!elems->mesh_id || !elems->mesh_config)) {
1069                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1070                 return;
1071         }
1072         /* Note the lines below are correct, the llid in the frame is the plid
1073          * from the point of view of this host.
1074          */
1075         plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1076         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1077             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1078                 llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1079
1080         /* WARNING: Only for sta pointer, is dropped & re-acquired */
1081         rcu_read_lock();
1082
1083         sta = sta_info_get(sdata, mgmt->sa);
1084
1085         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1086             !rssi_threshold_check(sdata, sta)) {
1087                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1088                         mgmt->sa);
1089                 goto unlock_rcu;
1090         }
1091
1092         /* Now we will figure out the appropriate event... */
1093         event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1094
1095         if (event == OPN_ACPT) {
1096                 rcu_read_unlock();
1097                 /* allocate sta entry if necessary and update info */
1098                 sta = mesh_sta_info_get(sdata, mgmt->sa, elems);
1099                 if (!sta) {
1100                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1101                         goto unlock_rcu;
1102                 }
1103                 sta->mesh->plid = plid;
1104         } else if (!sta && event == OPN_RJCT) {
1105                 mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1106                                     mgmt->sa, 0, plid,
1107                                     WLAN_REASON_MESH_CONFIG);
1108                 goto unlock_rcu;
1109         } else if (!sta || event == PLINK_UNDEFINED) {
1110                 /* something went wrong */
1111                 goto unlock_rcu;
1112         }
1113
1114         if (event == CNF_ACPT) {
1115                 /* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1116                 if (!sta->mesh->plid)
1117                         sta->mesh->plid = plid;
1118
1119                 sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1120         }
1121
1122         changed |= mesh_plink_fsm(sdata, sta, event);
1123
1124 unlock_rcu:
1125         rcu_read_unlock();
1126
1127         if (changed)
1128                 ieee80211_mbss_info_change_notify(sdata, changed);
1129 }
1130
1131 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1132                          struct ieee80211_mgmt *mgmt, size_t len,
1133                          struct ieee80211_rx_status *rx_status)
1134 {
1135         struct ieee802_11_elems elems;
1136         size_t baselen;
1137         u8 *baseaddr;
1138
1139         /* need action_code, aux */
1140         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1141                 return;
1142
1143         if (sdata->u.mesh.user_mpm)
1144                 /* userspace must register for these */
1145                 return;
1146
1147         if (is_multicast_ether_addr(mgmt->da)) {
1148                 mpl_dbg(sdata,
1149                         "Mesh plink: ignore frame from multicast address\n");
1150                 return;
1151         }
1152
1153         baseaddr = mgmt->u.action.u.self_prot.variable;
1154         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1155         if (mgmt->u.action.u.self_prot.action_code ==
1156                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
1157                 baseaddr += 4;
1158                 baselen += 4;
1159
1160                 if (baselen > len)
1161                         return;
1162         }
1163         ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems);
1164         mesh_process_plink_frame(sdata, mgmt, &elems);
1165 }