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 &&
  64                 (s8)-ewma_signal_read(&sta->rx_stats.avg_signal) >
  65                                                 rssi_threshold);
  66 }
  67
  68 /**
  69  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  70  *
  71  * @sta: mesh peer link to restart
  72  *
  73  * Locking: this function must be called holding sta->mesh->plink_lock
  74  */
  75 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  76 {
  77         lockdep_assert_held(&sta->mesh->plink_lock);
  78         sta->mesh->plink_state = NL80211_PLINK_LISTEN;
  79         sta->mesh->llid = sta->mesh->plid = sta->mesh->reason = 0;
  80         sta->mesh->plink_retries = 0;
  81 }
  82
  83 /*
  84  * mesh_set_short_slot_time - enable / disable ERP short slot time.
  85  *
  86  * The standard indirectly mandates mesh STAs to turn off short slot time by
  87  * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
  88  * can't be sneaky about it. Enable short slot time if all mesh STAs in the
  89  * MBSS support ERP rates.
  90  *
  91  * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
  92  */
  93 static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
  94 {
  95         struct ieee80211_local *local = sdata->local;
  96         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
  97         struct ieee80211_supported_band *sband = local->hw.wiphy->bands[band];
  98         struct sta_info *sta;
  99         u32 erp_rates = 0, changed = 0;
 100         int i;
 101         bool short_slot = false;
 102
 103         if (band == IEEE80211_BAND_5GHZ) {
 104                 /* (IEEE 802.11-2012 19.4.5) */
 105                 short_slot = true;
 106                 goto out;
 107         } else if (band != IEEE80211_BAND_2GHZ)
 108                 goto out;
 109
 110         for (i = 0; i < sband->n_bitrates; i++)
 111                 if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
 112                         erp_rates |= BIT(i);
 113
 114         if (!erp_rates)
 115                 goto out;
 116
 117         rcu_read_lock();
 118         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 119                 if (sdata != sta->sdata ||
 120                     sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 121                         continue;
 122
 123                 short_slot = false;
 124                 if (erp_rates & sta->sta.supp_rates[band])
 125                         short_slot = true;
 126                  else
 127                         break;
 128         }
 129         rcu_read_unlock();
 130
 131 out:
 132         if (sdata->vif.bss_conf.use_short_slot != short_slot) {
 133                 sdata->vif.bss_conf.use_short_slot = short_slot;
 134                 changed = BSS_CHANGED_ERP_SLOT;
 135                 mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
 136                         sdata->vif.addr, short_slot);
 137         }
 138         return changed;
 139 }
 140
 141 /**
 142  * mesh_set_ht_prot_mode - set correct HT protection mode
 143  *
 144  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 145  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 146  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 147  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 148  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 149  * HT20 peer is present. Otherwise no-protection mode is selected.
 150  */
 151 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 152 {
 153         struct ieee80211_local *local = sdata->local;
 154         struct sta_info *sta;
 155         u16 ht_opmode;
 156         bool non_ht_sta = false, ht20_sta = false;
 157
 158         switch (sdata->vif.bss_conf.chandef.width) {
 159         case NL80211_CHAN_WIDTH_20_NOHT:
 160         case NL80211_CHAN_WIDTH_5:
 161         case NL80211_CHAN_WIDTH_10:
 162                 return 0;
 163         default:
 164                 break;
 165         }
 166
 167         rcu_read_lock();
 168         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 169                 if (sdata != sta->sdata ||
 170                     sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 171                         continue;
 172
 173                 if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
 174                         continue;
 175
 176                 if (!sta->sta.ht_cap.ht_supported) {
 177                         mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
 178                                        sta->sta.addr);
 179                         non_ht_sta = true;
 180                         break;
 181                 }
 182
 183                 mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
 184                 ht20_sta = true;
 185         }
 186         rcu_read_unlock();
 187
 188         if (non_ht_sta)
 189                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 190         else if (ht20_sta &&
 191                  sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
 192                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 193         else
 194                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 195
 196         if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
 197                 return 0;
 198
 199         sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 200         sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 201         mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
 202         return BSS_CHANGED_HT;
 203 }
 204
 205 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 206                                struct sta_info *sta,
 207                                enum ieee80211_self_protected_actioncode action,
 208                                u8 *da, u16 llid, u16 plid, u16 reason)
 209 {
 210         struct ieee80211_local *local = sdata->local;
 211         struct sk_buff *skb;
 212         struct ieee80211_tx_info *info;
 213         struct ieee80211_mgmt *mgmt;
 214         bool include_plid = false;
 215         u16 peering_proto = 0;
 216         u8 *pos, ie_len = 4;
 217         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 218                       sizeof(mgmt->u.action.u.self_prot);
 219         int err = -ENOMEM;
 220
 221         skb = dev_alloc_skb(local->tx_headroom +
 222                             hdr_len +
 223                             2 + /* capability info */
 224                             2 + /* AID */
 225                             2 + 8 + /* supported rates */
 226                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 227                             2 + sdata->u.mesh.mesh_id_len +
 228                             2 + sizeof(struct ieee80211_meshconf_ie) +
 229                             2 + sizeof(struct ieee80211_ht_cap) +
 230                             2 + sizeof(struct ieee80211_ht_operation) +
 231                             2 + sizeof(struct ieee80211_vht_cap) +
 232                             2 + sizeof(struct ieee80211_vht_operation) +
 233                             2 + 8 + /* peering IE */
 234                             sdata->u.mesh.ie_len);
 235         if (!skb)
 236                 return err;
 237         info = IEEE80211_SKB_CB(skb);
 238         skb_reserve(skb, local->tx_headroom);
 239         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 240         memset(mgmt, 0, hdr_len);
 241         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 242                                           IEEE80211_STYPE_ACTION);
 243         memcpy(mgmt->da, da, ETH_ALEN);
 244         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 245         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 246         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 247         mgmt->u.action.u.self_prot.action_code = action;
 248
 249         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 250                 enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 251
 252                 /* capability info */
 253                 pos = skb_put(skb, 2);
 254                 memset(pos, 0, 2);
 255                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 256                         /* AID */
 257                         pos = skb_put(skb, 2);
 258                         put_unaligned_le16(sta->sta.aid, pos);
 259                 }
 260                 if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
 261                     ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
 262                     mesh_add_rsn_ie(sdata, skb) ||
 263                     mesh_add_meshid_ie(sdata, skb) ||
 264                     mesh_add_meshconf_ie(sdata, skb))
 265                         goto free;
 266         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 267                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
 268                 if (mesh_add_meshid_ie(sdata, skb))
 269                         goto free;
 270         }
 271
 272         /* Add Mesh Peering Management element */
 273         switch (action) {
 274         case WLAN_SP_MESH_PEERING_OPEN:
 275                 break;
 276         case WLAN_SP_MESH_PEERING_CONFIRM:
 277                 ie_len += 2;
 278                 include_plid = true;
 279                 break;
 280         case WLAN_SP_MESH_PEERING_CLOSE:
 281                 if (plid) {
 282                         ie_len += 2;
 283                         include_plid = true;
 284                 }
 285                 ie_len += 2;    /* reason code */
 286                 break;
 287         default:
 288                 err = -EINVAL;
 289                 goto free;
 290         }
 291
 292         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 293                 goto free;
 294
 295         pos = skb_put(skb, 2 + ie_len);
 296         *pos++ = WLAN_EID_PEER_MGMT;
 297         *pos++ = ie_len;
 298         memcpy(pos, &peering_proto, 2);
 299         pos += 2;
 300         put_unaligned_le16(llid, pos);
 301         pos += 2;
 302         if (include_plid) {
 303                 put_unaligned_le16(plid, pos);
 304                 pos += 2;
 305         }
 306         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 307                 put_unaligned_le16(reason, pos);
 308                 pos += 2;
 309         }
 310
 311         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 312                 if (mesh_add_ht_cap_ie(sdata, skb) ||
 313                     mesh_add_ht_oper_ie(sdata, skb) ||
 314                     mesh_add_vht_cap_ie(sdata, skb) ||
 315                     mesh_add_vht_oper_ie(sdata, skb))
 316                         goto free;
 317         }
 318
 319         if (mesh_add_vendor_ies(sdata, skb))
 320                 goto free;
 321
 322         ieee80211_tx_skb(sdata, skb);
 323         return 0;
 324 free:
 325         kfree_skb(skb);
 326         return err;
 327 }
 328
 329 /**
 330  * __mesh_plink_deactivate - deactivate mesh peer link
 331  *
 332  * @sta: mesh peer link to deactivate
 333  *
 334  * All mesh paths with this peer as next hop will be flushed
 335  * Returns beacon changed flag if the beacon content changed.
 336  *
 337  * Locking: the caller must hold sta->mesh->plink_lock
 338  */
 339 static u32 __mesh_plink_deactivate(struct sta_info *sta)
 340 {
 341         struct ieee80211_sub_if_data *sdata = sta->sdata;
 342         u32 changed = 0;
 343
 344         lockdep_assert_held(&sta->mesh->plink_lock);
 345
 346         if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
 347                 changed = mesh_plink_dec_estab_count(sdata);
 348         sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 349         mesh_path_flush_by_nexthop(sta);
 350
 351         ieee80211_mps_sta_status_update(sta);
 352         changed |= ieee80211_mps_set_sta_local_pm(sta,
 353                         NL80211_MESH_POWER_UNKNOWN);
 354
 355         return changed;
 356 }
 357
 358 /**
 359  * mesh_plink_deactivate - deactivate mesh peer link
 360  *
 361  * @sta: mesh peer link to deactivate
 362  *
 363  * All mesh paths with this peer as next hop will be flushed
 364  */
 365 u32 mesh_plink_deactivate(struct sta_info *sta)
 366 {
 367         struct ieee80211_sub_if_data *sdata = sta->sdata;
 368         u32 changed;
 369
 370         spin_lock_bh(&sta->mesh->plink_lock);
 371         changed = __mesh_plink_deactivate(sta);
 372         sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
 373         mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
 374                             sta->sta.addr, sta->mesh->llid, sta->mesh->plid,
 375                             sta->mesh->reason);
 376         spin_unlock_bh(&sta->mesh->plink_lock);
 377
 378         return changed;
 379 }
 380
 381 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
 382                                struct sta_info *sta,
 383                                struct ieee802_11_elems *elems, bool insert)
 384 {
 385         struct ieee80211_local *local = sdata->local;
 386         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 387         struct ieee80211_supported_band *sband;
 388         u32 rates, basic_rates = 0, changed = 0;
 389         enum ieee80211_sta_rx_bandwidth bw = sta->sta.bandwidth;
 390
 391         sband = local->hw.wiphy->bands[band];
 392         rates = ieee80211_sta_get_rates(sdata, elems, band, &basic_rates);
 393
 394         spin_lock_bh(&sta->mesh->plink_lock);
 395         sta->rx_stats.last_rx = jiffies;
 396
 397         /* rates and capabilities don't change during peering */
 398         if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
 399             sta->mesh->processed_beacon)
 400                 goto out;
 401         sta->mesh->processed_beacon = true;
 402
 403         if (sta->sta.supp_rates[band] != rates)
 404                 changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
 405         sta->sta.supp_rates[band] = rates;
 406
 407         if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 408                                               elems->ht_cap_elem, sta))
 409                 changed |= IEEE80211_RC_BW_CHANGED;
 410
 411         ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
 412                                             elems->vht_cap_elem, sta);
 413
 414         if (bw != sta->sta.bandwidth)
 415                 changed |= IEEE80211_RC_BW_CHANGED;
 416
 417         /* HT peer is operating 20MHz-only */
 418         if (elems->ht_operation &&
 419             !(elems->ht_operation->ht_param &
 420               IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
 421                 if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
 422                         changed |= IEEE80211_RC_BW_CHANGED;
 423                 sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
 424         }
 425
 426         if (insert)
 427                 rate_control_rate_init(sta);
 428         else
 429                 rate_control_rate_update(local, sband, sta, changed);
 430 out:
 431         spin_unlock_bh(&sta->mesh->plink_lock);
 432 }
 433
 434 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
 435 {
 436         struct sta_info *sta;
 437         unsigned long *aid_map;
 438         int aid;
 439
 440         aid_map = kcalloc(BITS_TO_LONGS(IEEE80211_MAX_AID + 1),
 441                           sizeof(*aid_map), GFP_KERNEL);
 442         if (!aid_map)
 443                 return -ENOMEM;
 444
 445         /* reserve aid 0 for mcast indication */
 446         __set_bit(0, aid_map);
 447
 448         rcu_read_lock();
 449         list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
 450                 __set_bit(sta->sta.aid, aid_map);
 451         rcu_read_unlock();
 452
 453         aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
 454         kfree(aid_map);
 455
 456         if (aid > IEEE80211_MAX_AID)
 457                 return -ENOBUFS;
 458
 459         return aid;
 460 }
 461
 462 static struct sta_info *
 463 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
 464 {
 465         struct sta_info *sta;
 466         int aid;
 467
 468         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
 469                 return NULL;
 470
 471         aid = mesh_allocate_aid(sdata);
 472         if (aid < 0)
 473                 return NULL;
 474
 475         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 476         if (!sta)
 477                 return NULL;
 478
 479         sta->mesh->plink_state = NL80211_PLINK_LISTEN;
 480         sta->sta.wme = true;
 481         sta->sta.aid = aid;
 482
 483         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 484         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 485         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 486
 487         return sta;
 488 }
 489
 490 static struct sta_info *
 491 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
 492                     struct ieee802_11_elems *elems)
 493 {
 494         struct sta_info *sta = NULL;
 495
 496         /* Userspace handles station allocation */
 497         if (sdata->u.mesh.user_mpm ||
 498             sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
 499                 cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 500                                                    elems->ie_start,
 501                                                    elems->total_len,
 502                                                    GFP_KERNEL);
 503         else
 504                 sta = __mesh_sta_info_alloc(sdata, addr);
 505
 506         return sta;
 507 }
 508
 509 /*
 510  * mesh_sta_info_get - return mesh sta info entry for @addr.
 511  *
 512  * @sdata: local meshif
 513  * @addr: peer's address
 514  * @elems: IEs from beacon or mesh peering frame.
 515  *
 516  * Return existing or newly allocated sta_info under RCU read lock.
 517  * (re)initialize with given IEs.
 518  */
 519 static struct sta_info *
 520 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
 521                   u8 *addr, struct ieee802_11_elems *elems) __acquires(RCU)
 522 {
 523         struct sta_info *sta = NULL;
 524
 525         rcu_read_lock();
 526         sta = sta_info_get(sdata, addr);
 527         if (sta) {
 528                 mesh_sta_info_init(sdata, sta, elems, false);
 529         } else {
 530                 rcu_read_unlock();
 531                 /* can't run atomic */
 532                 sta = mesh_sta_info_alloc(sdata, addr, elems);
 533                 if (!sta) {
 534                         rcu_read_lock();
 535                         return NULL;
 536                 }
 537
 538                 mesh_sta_info_init(sdata, sta, elems, true);
 539
 540                 if (sta_info_insert_rcu(sta))
 541                         return NULL;
 542         }
 543
 544         return sta;
 545 }
 546
 547 /*
 548  * mesh_neighbour_update - update or initialize new mesh neighbor.
 549  *
 550  * @sdata: local meshif
 551  * @addr: peer's address
 552  * @elems: IEs from beacon or mesh peering frame
 553  *
 554  * Initiates peering if appropriate.
 555  */
 556 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 557                            u8 *hw_addr,
 558                            struct ieee802_11_elems *elems)
 559 {
 560         struct sta_info *sta;
 561         u32 changed = 0;
 562
 563         sta = mesh_sta_info_get(sdata, hw_addr, elems);
 564         if (!sta)
 565                 goto out;
 566
 567         if (mesh_peer_accepts_plinks(elems) &&
 568             sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
 569             sdata->u.mesh.accepting_plinks &&
 570             sdata->u.mesh.mshcfg.auto_open_plinks &&
 571             rssi_threshold_check(sdata, sta))
 572                 changed = mesh_plink_open(sta);
 573
 574         ieee80211_mps_frame_release(sta, elems);
 575 out:
 576         rcu_read_unlock();
 577         ieee80211_mbss_info_change_notify(sdata, changed);
 578 }
 579
 580 static void mesh_plink_timer(unsigned long data)
 581 {
 582         struct sta_info *sta;
 583         u16 reason = 0;
 584         struct ieee80211_sub_if_data *sdata;
 585         struct mesh_config *mshcfg;
 586         enum ieee80211_self_protected_actioncode action = 0;
 587
 588         /*
 589          * This STA is valid because sta_info_destroy() will
 590          * del_timer_sync() this timer after having made sure
 591          * it cannot be readded (by deleting the plink.)
 592          */
 593         sta = (struct sta_info *) data;
 594
 595         if (sta->sdata->local->quiescing)
 596                 return;
 597
 598         spin_lock_bh(&sta->mesh->plink_lock);
 599
 600         /* If a timer fires just before a state transition on another CPU,
 601          * we may have already extended the timeout and changed state by the
 602          * time we've acquired the lock and arrived  here.  In that case,
 603          * skip this timer and wait for the new one.
 604          */
 605         if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
 606                 mpl_dbg(sta->sdata,
 607                         "Ignoring timer for %pM in state %s (timer adjusted)",
 608                         sta->sta.addr, mplstates[sta->mesh->plink_state]);
 609                 spin_unlock_bh(&sta->mesh->plink_lock);
 610                 return;
 611         }
 612
 613         /* del_timer() and handler may race when entering these states */
 614         if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
 615             sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
 616                 mpl_dbg(sta->sdata,
 617                         "Ignoring timer for %pM in state %s (timer deleted)",
 618                         sta->sta.addr, mplstates[sta->mesh->plink_state]);
 619                 spin_unlock_bh(&sta->mesh->plink_lock);
 620                 return;
 621         }
 622
 623         mpl_dbg(sta->sdata,
 624                 "Mesh plink timer for %pM fired on state %s\n",
 625                 sta->sta.addr, mplstates[sta->mesh->plink_state]);
 626         sdata = sta->sdata;
 627         mshcfg = &sdata->u.mesh.mshcfg;
 628
 629         switch (sta->mesh->plink_state) {
 630         case NL80211_PLINK_OPN_RCVD:
 631         case NL80211_PLINK_OPN_SNT:
 632                 /* retry timer */
 633                 if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
 634                         u32 rand;
 635                         mpl_dbg(sta->sdata,
 636                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 637                                 sta->sta.addr, sta->mesh->plink_retries,
 638                                 sta->mesh->plink_timeout);
 639                         get_random_bytes(&rand, sizeof(u32));
 640                         sta->mesh->plink_timeout = sta->mesh->plink_timeout +
 641                                              rand % sta->mesh->plink_timeout;
 642                         ++sta->mesh->plink_retries;
 643                         mod_plink_timer(sta, sta->mesh->plink_timeout);
 644                         action = WLAN_SP_MESH_PEERING_OPEN;
 645                         break;
 646                 }
 647                 reason = WLAN_REASON_MESH_MAX_RETRIES;
 648                 /* fall through on else */
 649         case NL80211_PLINK_CNF_RCVD:
 650                 /* confirm timer */
 651                 if (!reason)
 652                         reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
 653                 sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 654                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 655                 action = WLAN_SP_MESH_PEERING_CLOSE;
 656                 break;
 657         case NL80211_PLINK_HOLDING:
 658                 /* holding timer */
 659                 del_timer(&sta->mesh->plink_timer);
 660                 mesh_plink_fsm_restart(sta);
 661                 break;
 662         default:
 663                 break;
 664         }
 665         spin_unlock_bh(&sta->mesh->plink_lock);
 666         if (action)
 667                 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 668                                     sta->mesh->llid, sta->mesh->plid, reason);
 669 }
 670
 671 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
 672 {
 673         sta->mesh->plink_timer.expires = jiffies + msecs_to_jiffies(timeout);
 674         sta->mesh->plink_timer.data = (unsigned long) sta;
 675         sta->mesh->plink_timer.function = mesh_plink_timer;
 676         sta->mesh->plink_timeout = timeout;
 677         add_timer(&sta->mesh->plink_timer);
 678 }
 679
 680 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
 681                         u16 llid)
 682 {
 683         struct ieee80211_local *local = sdata->local;
 684         bool in_use = false;
 685         struct sta_info *sta;
 686
 687         rcu_read_lock();
 688         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 689                 if (sdata != sta->sdata)
 690                         continue;
 691
 692                 if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
 693                         in_use = true;
 694                         break;
 695                 }
 696         }
 697         rcu_read_unlock();
 698
 699         return in_use;
 700 }
 701
 702 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 703 {
 704         u16 llid;
 705
 706         do {
 707                 get_random_bytes(&llid, sizeof(llid));
 708         } while (llid_in_use(sdata, llid));
 709
 710         return llid;
 711 }
 712
 713 u32 mesh_plink_open(struct sta_info *sta)
 714 {
 715         struct ieee80211_sub_if_data *sdata = sta->sdata;
 716         u32 changed;
 717
 718         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 719                 return 0;
 720
 721         spin_lock_bh(&sta->mesh->plink_lock);
 722         sta->mesh->llid = mesh_get_new_llid(sdata);
 723         if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
 724             sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
 725                 spin_unlock_bh(&sta->mesh->plink_lock);
 726                 return 0;
 727         }
 728         sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
 729         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 730         spin_unlock_bh(&sta->mesh->plink_lock);
 731         mpl_dbg(sdata,
 732                 "Mesh plink: starting establishment with %pM\n",
 733                 sta->sta.addr);
 734
 735         /* set the non-peer mode to active during peering */
 736         changed = ieee80211_mps_local_status_update(sdata);
 737
 738         mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
 739                             sta->sta.addr, sta->mesh->llid, 0, 0);
 740         return changed;
 741 }
 742
 743 u32 mesh_plink_block(struct sta_info *sta)
 744 {
 745         u32 changed;
 746
 747         spin_lock_bh(&sta->mesh->plink_lock);
 748         changed = __mesh_plink_deactivate(sta);
 749         sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 750         spin_unlock_bh(&sta->mesh->plink_lock);
 751
 752         return changed;
 753 }
 754
 755 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
 756                              struct sta_info *sta,
 757                              enum plink_event event)
 758 {
 759         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 760         u16 reason = (event == CLS_ACPT) ?
 761                      WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
 762
 763         sta->mesh->reason = reason;
 764         sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 765         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 766 }
 767
 768 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
 769                                 struct sta_info *sta)
 770 {
 771         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 772         u32 changed = 0;
 773
 774         del_timer(&sta->mesh->plink_timer);
 775         sta->mesh->plink_state = NL80211_PLINK_ESTAB;
 776         changed |= mesh_plink_inc_estab_count(sdata);
 777         changed |= mesh_set_ht_prot_mode(sdata);
 778         changed |= mesh_set_short_slot_time(sdata);
 779         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
 780         ieee80211_mps_sta_status_update(sta);
 781         changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
 782         return changed;
 783 }
 784
 785 /**
 786  * mesh_plink_fsm - step @sta MPM based on @event
 787  *
 788  * @sdata: interface
 789  * @sta: mesh neighbor
 790  * @event: peering event
 791  *
 792  * Return: changed MBSS flags
 793  */
 794 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
 795                           struct sta_info *sta, enum plink_event event)
 796 {
 797         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 798         enum ieee80211_self_protected_actioncode action = 0;
 799         u32 changed = 0;
 800
 801         mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
 802                 mplstates[sta->mesh->plink_state], mplevents[event]);
 803
 804         spin_lock_bh(&sta->mesh->plink_lock);
 805         switch (sta->mesh->plink_state) {
 806         case NL80211_PLINK_LISTEN:
 807                 switch (event) {
 808                 case CLS_ACPT:
 809                         mesh_plink_fsm_restart(sta);
 810                         break;
 811                 case OPN_ACPT:
 812                         sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 813                         sta->mesh->llid = mesh_get_new_llid(sdata);
 814                         mesh_plink_timer_set(sta,
 815                                              mshcfg->dot11MeshRetryTimeout);
 816
 817                         /* set the non-peer mode to active during peering */
 818                         changed |= ieee80211_mps_local_status_update(sdata);
 819                         action = WLAN_SP_MESH_PEERING_OPEN;
 820                         break;
 821                 default:
 822                         break;
 823                 }
 824                 break;
 825         case NL80211_PLINK_OPN_SNT:
 826                 switch (event) {
 827                 case OPN_RJCT:
 828                 case CNF_RJCT:
 829                 case CLS_ACPT:
 830                         mesh_plink_close(sdata, sta, event);
 831                         action = WLAN_SP_MESH_PEERING_CLOSE;
 832                         break;
 833                 case OPN_ACPT:
 834                         /* retry timer is left untouched */
 835                         sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 836                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 837                         break;
 838                 case CNF_ACPT:
 839                         sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
 840                         mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
 841                         break;
 842                 default:
 843                         break;
 844                 }
 845                 break;
 846         case NL80211_PLINK_OPN_RCVD:
 847                 switch (event) {
 848                 case OPN_RJCT:
 849                 case CNF_RJCT:
 850                 case CLS_ACPT:
 851                         mesh_plink_close(sdata, sta, event);
 852                         action = WLAN_SP_MESH_PEERING_CLOSE;
 853                         break;
 854                 case OPN_ACPT:
 855                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 856                         break;
 857                 case CNF_ACPT:
 858                         changed |= mesh_plink_establish(sdata, sta);
 859                         break;
 860                 default:
 861                         break;
 862                 }
 863                 break;
 864         case NL80211_PLINK_CNF_RCVD:
 865                 switch (event) {
 866                 case OPN_RJCT:
 867                 case CNF_RJCT:
 868                 case CLS_ACPT:
 869                         mesh_plink_close(sdata, sta, event);
 870                         action = WLAN_SP_MESH_PEERING_CLOSE;
 871                         break;
 872                 case OPN_ACPT:
 873                         changed |= mesh_plink_establish(sdata, sta);
 874                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 875                         break;
 876                 default:
 877                         break;
 878                 }
 879                 break;
 880         case NL80211_PLINK_ESTAB:
 881                 switch (event) {
 882                 case CLS_ACPT:
 883                         changed |= __mesh_plink_deactivate(sta);
 884                         changed |= mesh_set_ht_prot_mode(sdata);
 885                         changed |= mesh_set_short_slot_time(sdata);
 886                         mesh_plink_close(sdata, sta, event);
 887                         action = WLAN_SP_MESH_PEERING_CLOSE;
 888                         break;
 889                 case OPN_ACPT:
 890                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 891                         break;
 892                 default:
 893                         break;
 894                 }
 895                 break;
 896         case NL80211_PLINK_HOLDING:
 897                 switch (event) {
 898                 case CLS_ACPT:
 899                         del_timer(&sta->mesh->plink_timer);
 900                         mesh_plink_fsm_restart(sta);
 901                         break;
 902                 case OPN_ACPT:
 903                 case CNF_ACPT:
 904                 case OPN_RJCT:
 905                 case CNF_RJCT:
 906                         action = WLAN_SP_MESH_PEERING_CLOSE;
 907                         break;
 908                 default:
 909                         break;
 910                 }
 911                 break;
 912         default:
 913                 /* should not get here, PLINK_BLOCKED is dealt with at the
 914                  * beginning of the function
 915                  */
 916                 break;
 917         }
 918         spin_unlock_bh(&sta->mesh->plink_lock);
 919         if (action) {
 920                 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 921                                     sta->mesh->llid, sta->mesh->plid,
 922                                     sta->mesh->reason);
 923
 924                 /* also send confirm in open case */
 925                 if (action == WLAN_SP_MESH_PEERING_OPEN) {
 926                         mesh_plink_frame_tx(sdata, sta,
 927                                             WLAN_SP_MESH_PEERING_CONFIRM,
 928                                             sta->sta.addr, sta->mesh->llid,
 929                                             sta->mesh->plid, 0);
 930                 }
 931         }
 932
 933         return changed;
 934 }
 935
 936 /*
 937  * mesh_plink_get_event - get correct MPM event
 938  *
 939  * @sdata: interface
 940  * @sta: peer, leave NULL if processing a frame from a new suitable peer
 941  * @elems: peering management IEs
 942  * @ftype: frame type
 943  * @llid: peer's peer link ID
 944  * @plid: peer's local link ID
 945  *
 946  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
 947  * an error.
 948  */
 949 static enum plink_event
 950 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
 951                      struct sta_info *sta,
 952                      struct ieee802_11_elems *elems,
 953                      enum ieee80211_self_protected_actioncode ftype,
 954                      u16 llid, u16 plid)
 955 {
 956         enum plink_event event = PLINK_UNDEFINED;
 957         u8 ie_len = elems->peering_len;
 958         bool matches_local;
 959
 960         matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
 961                          mesh_matches_local(sdata, elems));
 962
 963         /* deny open request from non-matching peer */
 964         if (!matches_local && !sta) {
 965                 event = OPN_RJCT;
 966                 goto out;
 967         }
 968
 969         if (!sta) {
 970                 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
 971                         mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 972                         goto out;
 973                 }
 974                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 975                 if (!mesh_plink_free_count(sdata)) {
 976                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 977                         goto out;
 978                 }
 979
 980                 /* new matching peer */
 981                 event = OPN_ACPT;
 982                 goto out;
 983         } else {
 984                 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
 985                         mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 986                         goto out;
 987                 }
 988                 if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
 989                         goto out;
 990         }
 991
 992         switch (ftype) {
 993         case WLAN_SP_MESH_PEERING_OPEN:
 994                 if (!matches_local)
 995                         event = OPN_RJCT;
 996                 if (!mesh_plink_free_count(sdata) ||
 997                     (sta->mesh->plid && sta->mesh->plid != plid))
 998                         event = OPN_IGNR;
 999                 else
1000                         event = OPN_ACPT;
1001                 break;
1002         case WLAN_SP_MESH_PEERING_CONFIRM:
1003                 if (!matches_local)
1004                         event = CNF_RJCT;
1005                 if (!mesh_plink_free_count(sdata) ||
1006                     sta->mesh->llid != llid ||
1007                     (sta->mesh->plid && sta->mesh->plid != plid))
1008                         event = CNF_IGNR;
1009                 else
1010                         event = CNF_ACPT;
1011                 break;
1012         case WLAN_SP_MESH_PEERING_CLOSE:
1013                 if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1014                         /* Do not check for llid or plid. This does not
1015                          * follow the standard but since multiple plinks
1016                          * per sta are not supported, it is necessary in
1017                          * order to avoid a livelock when MP A sees an
1018                          * establish peer link to MP B but MP B does not
1019                          * see it. This can be caused by a timeout in
1020                          * B's peer link establishment or B beign
1021                          * restarted.
1022                          */
1023                         event = CLS_ACPT;
1024                 else if (sta->mesh->plid != plid)
1025                         event = CLS_IGNR;
1026                 else if (ie_len == 8 && sta->mesh->llid != llid)
1027                         event = CLS_IGNR;
1028                 else
1029                         event = CLS_ACPT;
1030                 break;
1031         default:
1032                 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1033                 break;
1034         }
1035
1036 out:
1037         return event;
1038 }
1039
1040 static void
1041 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1042                          struct ieee80211_mgmt *mgmt,
1043                          struct ieee802_11_elems *elems)
1044 {
1045
1046         struct sta_info *sta;
1047         enum plink_event event;
1048         enum ieee80211_self_protected_actioncode ftype;
1049         u32 changed = 0;
1050         u8 ie_len = elems->peering_len;
1051         u16 plid, llid = 0;
1052
1053         if (!elems->peering) {
1054                 mpl_dbg(sdata,
1055                         "Mesh plink: missing necessary peer link ie\n");
1056                 return;
1057         }
1058
1059         if (elems->rsn_len &&
1060             sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1061                 mpl_dbg(sdata,
1062                         "Mesh plink: can't establish link with secure peer\n");
1063                 return;
1064         }
1065
1066         ftype = mgmt->u.action.u.self_prot.action_code;
1067         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1068             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1069             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1070                                                         && ie_len != 8)) {
1071                 mpl_dbg(sdata,
1072                         "Mesh plink: incorrect plink ie length %d %d\n",
1073                         ftype, ie_len);
1074                 return;
1075         }
1076
1077         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1078             (!elems->mesh_id || !elems->mesh_config)) {
1079                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1080                 return;
1081         }
1082         /* Note the lines below are correct, the llid in the frame is the plid
1083          * from the point of view of this host.
1084          */
1085         plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1086         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1087             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1088                 llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1089
1090         /* WARNING: Only for sta pointer, is dropped & re-acquired */
1091         rcu_read_lock();
1092
1093         sta = sta_info_get(sdata, mgmt->sa);
1094
1095         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1096             !rssi_threshold_check(sdata, sta)) {
1097                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1098                         mgmt->sa);
1099                 goto unlock_rcu;
1100         }
1101
1102         /* Now we will figure out the appropriate event... */
1103         event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1104
1105         if (event == OPN_ACPT) {
1106                 rcu_read_unlock();
1107                 /* allocate sta entry if necessary and update info */
1108                 sta = mesh_sta_info_get(sdata, mgmt->sa, elems);
1109                 if (!sta) {
1110                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1111                         goto unlock_rcu;
1112                 }
1113                 sta->mesh->plid = plid;
1114         } else if (!sta && event == OPN_RJCT) {
1115                 mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1116                                     mgmt->sa, 0, plid,
1117                                     WLAN_REASON_MESH_CONFIG);
1118                 goto unlock_rcu;
1119         } else if (!sta || event == PLINK_UNDEFINED) {
1120                 /* something went wrong */
1121                 goto unlock_rcu;
1122         }
1123
1124         if (event == CNF_ACPT) {
1125                 /* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1126                 if (!sta->mesh->plid)
1127                         sta->mesh->plid = plid;
1128
1129                 sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1130         }
1131
1132         changed |= mesh_plink_fsm(sdata, sta, event);
1133
1134 unlock_rcu:
1135         rcu_read_unlock();
1136
1137         if (changed)
1138                 ieee80211_mbss_info_change_notify(sdata, changed);
1139 }
1140
1141 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1142                          struct ieee80211_mgmt *mgmt, size_t len,
1143                          struct ieee80211_rx_status *rx_status)
1144 {
1145         struct ieee802_11_elems elems;
1146         size_t baselen;
1147         u8 *baseaddr;
1148
1149         /* need action_code, aux */
1150         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1151                 return;
1152
1153         if (sdata->u.mesh.user_mpm)
1154                 /* userspace must register for these */
1155                 return;
1156
1157         if (is_multicast_ether_addr(mgmt->da)) {
1158                 mpl_dbg(sdata,
1159                         "Mesh plink: ignore frame from multicast address\n");
1160                 return;
1161         }
1162
1163         baseaddr = mgmt->u.action.u.self_prot.variable;
1164         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1165         if (mgmt->u.action.u.self_prot.action_code ==
1166                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
1167                 baseaddr += 4;
1168                 baselen += 4;
1169
1170                 if (baselen > len)
1171                         return;
1172         }
1173         ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems);
1174         mesh_process_plink_frame(sdata, mgmt, &elems);
1175 }