net/mac80211/mesh_plink.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9 #include <linux/gfp.h>
  10 #include <linux/kernel.h>
  11 #include <linux/random.h>
  12 #include "ieee80211_i.h"
  13 #include "rate.h"
  14 #include "mesh.h"
  15
  16 #define PLINK_GET_LLID(p) (p + 2)
  17 #define PLINK_GET_PLID(p) (p + 4)
  18
  19 #define mod_plink_timer(s, t) (mod_timer(&s->plink_timer, \
  20                                 jiffies + HZ * t / 1000))
  21
  22 enum plink_event {
  23         PLINK_UNDEFINED,
  24         OPN_ACPT,
  25         OPN_RJCT,
  26         OPN_IGNR,
  27         CNF_ACPT,
  28         CNF_RJCT,
  29         CNF_IGNR,
  30         CLS_ACPT,
  31         CLS_IGNR
  32 };
  33
  34 static const char * const mplstates[] = {
  35         [NL80211_PLINK_LISTEN] = "LISTEN",
  36         [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
  37         [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
  38         [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
  39         [NL80211_PLINK_ESTAB] = "ESTAB",
  40         [NL80211_PLINK_HOLDING] = "HOLDING",
  41         [NL80211_PLINK_BLOCKED] = "BLOCKED"
  42 };
  43
  44 static const char * const mplevents[] = {
  45         [PLINK_UNDEFINED] = "NONE",
  46         [OPN_ACPT] = "OPN_ACPT",
  47         [OPN_RJCT] = "OPN_RJCT",
  48         [OPN_IGNR] = "OPN_IGNR",
  49         [CNF_ACPT] = "CNF_ACPT",
  50         [CNF_RJCT] = "CNF_RJCT",
  51         [CNF_IGNR] = "CNF_IGNR",
  52         [CLS_ACPT] = "CLS_ACPT",
  53         [CLS_IGNR] = "CLS_IGNR"
  54 };
  55
  56 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
  57                                enum ieee80211_self_protected_actioncode action,
  58                                u8 *da, u16 llid, u16 plid, u16 reason);
  59
  60
  61 /* We only need a valid sta if user configured a minimum rssi_threshold. */
  62 static bool rssi_threshold_check(struct ieee80211_sub_if_data *sdata,
  63                                  struct sta_info *sta)
  64 {
  65         s32 rssi_threshold = sdata->u.mesh.mshcfg.rssi_threshold;
  66         return rssi_threshold == 0 ||
  67                (sta && (s8) -ewma_read(&sta->avg_signal) > rssi_threshold);
  68 }
  69
  70 /**
  71  * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  72  *
  73  * @sta: mesh peer link to restart
  74  *
  75  * Locking: this function must be called holding sta->lock
  76  */
  77 static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  78 {
  79         sta->plink_state = NL80211_PLINK_LISTEN;
  80         sta->llid = sta->plid = sta->reason = 0;
  81         sta->plink_retries = 0;
  82 }
  83
  84 /*
  85  * mesh_set_short_slot_time - enable / disable ERP short slot time.
  86  *
  87  * The standard indirectly mandates mesh STAs to turn off short slot time by
  88  * disallowing advertising this (802.11-2012 8.4.1.4), but that doesn't mean we
  89  * can't be sneaky about it. Enable short slot time if all mesh STAs in the
  90  * MBSS support ERP rates.
  91  *
  92  * Returns BSS_CHANGED_ERP_SLOT or 0 for no change.
  93  */
  94 static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
  95 {
  96         struct ieee80211_local *local = sdata->local;
  97         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
  98         struct ieee80211_supported_band *sband = local->hw.wiphy->bands[band];
  99         struct sta_info *sta;
 100         u32 erp_rates = 0, changed = 0;
 101         int i;
 102         bool short_slot = false;
 103
 104         if (band == IEEE80211_BAND_5GHZ) {
 105                 /* (IEEE 802.11-2012 19.4.5) */
 106                 short_slot = true;
 107                 goto out;
 108         } else if (band != IEEE80211_BAND_2GHZ ||
 109                    (band == IEEE80211_BAND_2GHZ &&
 110                     local->hw.flags & IEEE80211_HW_2GHZ_SHORT_SLOT_INCAPABLE))
 111                 goto out;
 112
 113         for (i = 0; i < sband->n_bitrates; i++)
 114                 if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
 115                         erp_rates |= BIT(i);
 116
 117         if (!erp_rates)
 118                 goto out;
 119
 120         rcu_read_lock();
 121         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 122                 if (sdata != sta->sdata ||
 123                     sta->plink_state != NL80211_PLINK_ESTAB)
 124                         continue;
 125
 126                 short_slot = false;
 127                 if (erp_rates & sta->sta.supp_rates[band])
 128                         short_slot = true;
 129                  else
 130                         break;
 131         }
 132         rcu_read_unlock();
 133
 134 out:
 135         if (sdata->vif.bss_conf.use_short_slot != short_slot) {
 136                 sdata->vif.bss_conf.use_short_slot = short_slot;
 137                 changed = BSS_CHANGED_ERP_SLOT;
 138                 mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
 139                         sdata->vif.addr, short_slot);
 140         }
 141         return changed;
 142 }
 143
 144 /**
 145  * mesh_set_ht_prot_mode - set correct HT protection mode
 146  *
 147  * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 148  * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 149  * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 150  * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 151  * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 152  * HT20 peer is present. Otherwise no-protection mode is selected.
 153  */
 154 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 155 {
 156         struct ieee80211_local *local = sdata->local;
 157         struct sta_info *sta;
 158         u16 ht_opmode;
 159         bool non_ht_sta = false, ht20_sta = false;
 160
 161         switch (sdata->vif.bss_conf.chandef.width) {
 162         case NL80211_CHAN_WIDTH_20_NOHT:
 163         case NL80211_CHAN_WIDTH_5:
 164         case NL80211_CHAN_WIDTH_10:
 165                 return 0;
 166         default:
 167                 break;
 168         }
 169
 170         rcu_read_lock();
 171         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 172                 if (sdata != sta->sdata ||
 173                     sta->plink_state != NL80211_PLINK_ESTAB)
 174                         continue;
 175
 176                 if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
 177                         continue;
 178
 179                 if (!sta->sta.ht_cap.ht_supported) {
 180                         mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
 181                                        sta->sta.addr);
 182                         non_ht_sta = true;
 183                         break;
 184                 }
 185
 186                 mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
 187                 ht20_sta = true;
 188         }
 189         rcu_read_unlock();
 190
 191         if (non_ht_sta)
 192                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 193         else if (ht20_sta &&
 194                  sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
 195                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 196         else
 197                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 198
 199         if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
 200                 return 0;
 201
 202         sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 203         sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 204         mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
 205         return BSS_CHANGED_HT;
 206 }
 207
 208 /**
 209  * __mesh_plink_deactivate - deactivate mesh peer link
 210  *
 211  * @sta: mesh peer link to deactivate
 212  *
 213  * All mesh paths with this peer as next hop will be flushed
 214  * Returns beacon changed flag if the beacon content changed.
 215  *
 216  * Locking: the caller must hold sta->lock
 217  */
 218 static u32 __mesh_plink_deactivate(struct sta_info *sta)
 219 {
 220         struct ieee80211_sub_if_data *sdata = sta->sdata;
 221         u32 changed = 0;
 222
 223         if (sta->plink_state == NL80211_PLINK_ESTAB)
 224                 changed = mesh_plink_dec_estab_count(sdata);
 225         sta->plink_state = NL80211_PLINK_BLOCKED;
 226         mesh_path_flush_by_nexthop(sta);
 227
 228         ieee80211_mps_sta_status_update(sta);
 229         changed |= ieee80211_mps_set_sta_local_pm(sta,
 230                         NL80211_MESH_POWER_UNKNOWN);
 231
 232         return changed;
 233 }
 234
 235 /**
 236  * mesh_plink_deactivate - deactivate mesh peer link
 237  *
 238  * @sta: mesh peer link to deactivate
 239  *
 240  * All mesh paths with this peer as next hop will be flushed
 241  */
 242 u32 mesh_plink_deactivate(struct sta_info *sta)
 243 {
 244         struct ieee80211_sub_if_data *sdata = sta->sdata;
 245         u32 changed;
 246
 247         spin_lock_bh(&sta->lock);
 248         changed = __mesh_plink_deactivate(sta);
 249         sta->reason = WLAN_REASON_MESH_PEER_CANCELED;
 250         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 251                             sta->sta.addr, sta->llid, sta->plid,
 252                             sta->reason);
 253         spin_unlock_bh(&sta->lock);
 254
 255         return changed;
 256 }
 257
 258 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 259                                enum ieee80211_self_protected_actioncode action,
 260                                u8 *da, u16 llid, u16 plid, u16 reason)
 261 {
 262         struct ieee80211_local *local = sdata->local;
 263         struct sk_buff *skb;
 264         struct ieee80211_tx_info *info;
 265         struct ieee80211_mgmt *mgmt;
 266         bool include_plid = false;
 267         u16 peering_proto = 0;
 268         u8 *pos, ie_len = 4;
 269         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 270                       sizeof(mgmt->u.action.u.self_prot);
 271         int err = -ENOMEM;
 272
 273         skb = dev_alloc_skb(local->tx_headroom +
 274                             hdr_len +
 275                             2 + /* capability info */
 276                             2 + /* AID */
 277                             2 + 8 + /* supported rates */
 278                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 279                             2 + sdata->u.mesh.mesh_id_len +
 280                             2 + sizeof(struct ieee80211_meshconf_ie) +
 281                             2 + sizeof(struct ieee80211_ht_cap) +
 282                             2 + sizeof(struct ieee80211_ht_operation) +
 283                             2 + 8 + /* peering IE */
 284                             sdata->u.mesh.ie_len);
 285         if (!skb)
 286                 return err;
 287         info = IEEE80211_SKB_CB(skb);
 288         skb_reserve(skb, local->tx_headroom);
 289         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 290         memset(mgmt, 0, hdr_len);
 291         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 292                                           IEEE80211_STYPE_ACTION);
 293         memcpy(mgmt->da, da, ETH_ALEN);
 294         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 295         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 296         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 297         mgmt->u.action.u.self_prot.action_code = action;
 298
 299         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 300                 enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 301
 302                 /* capability info */
 303                 pos = skb_put(skb, 2);
 304                 memset(pos, 0, 2);
 305                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 306                         /* AID */
 307                         pos = skb_put(skb, 2);
 308                         put_unaligned_le16(plid, pos + 2);
 309                 }
 310                 if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
 311                     ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
 312                     mesh_add_rsn_ie(sdata, skb) ||
 313                     mesh_add_meshid_ie(sdata, skb) ||
 314                     mesh_add_meshconf_ie(sdata, skb))
 315                         goto free;
 316         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 317                 info->flags |= IEEE80211_TX_CTL_NO_ACK;
 318                 if (mesh_add_meshid_ie(sdata, skb))
 319                         goto free;
 320         }
 321
 322         /* Add Mesh Peering Management element */
 323         switch (action) {
 324         case WLAN_SP_MESH_PEERING_OPEN:
 325                 break;
 326         case WLAN_SP_MESH_PEERING_CONFIRM:
 327                 ie_len += 2;
 328                 include_plid = true;
 329                 break;
 330         case WLAN_SP_MESH_PEERING_CLOSE:
 331                 if (plid) {
 332                         ie_len += 2;
 333                         include_plid = true;
 334                 }
 335                 ie_len += 2;    /* reason code */
 336                 break;
 337         default:
 338                 err = -EINVAL;
 339                 goto free;
 340         }
 341
 342         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 343                 goto free;
 344
 345         pos = skb_put(skb, 2 + ie_len);
 346         *pos++ = WLAN_EID_PEER_MGMT;
 347         *pos++ = ie_len;
 348         memcpy(pos, &peering_proto, 2);
 349         pos += 2;
 350         put_unaligned_le16(llid, pos);
 351         pos += 2;
 352         if (include_plid) {
 353                 put_unaligned_le16(plid, pos);
 354                 pos += 2;
 355         }
 356         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 357                 put_unaligned_le16(reason, pos);
 358                 pos += 2;
 359         }
 360
 361         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 362                 if (mesh_add_ht_cap_ie(sdata, skb) ||
 363                     mesh_add_ht_oper_ie(sdata, skb))
 364                         goto free;
 365         }
 366
 367         if (mesh_add_vendor_ies(sdata, skb))
 368                 goto free;
 369
 370         ieee80211_tx_skb(sdata, skb);
 371         return 0;
 372 free:
 373         kfree_skb(skb);
 374         return err;
 375 }
 376
 377 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
 378                                struct sta_info *sta,
 379                                struct ieee802_11_elems *elems, bool insert)
 380 {
 381         struct ieee80211_local *local = sdata->local;
 382         enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
 383         struct ieee80211_supported_band *sband;
 384         u32 rates, basic_rates = 0, changed = 0;
 385
 386         sband = local->hw.wiphy->bands[band];
 387         rates = ieee80211_sta_get_rates(sdata, elems, band, &basic_rates);
 388
 389         spin_lock_bh(&sta->lock);
 390         sta->last_rx = jiffies;
 391
 392         /* rates and capabilities don't change during peering */
 393         if (sta->plink_state == NL80211_PLINK_ESTAB)
 394                 goto out;
 395
 396         if (sta->sta.supp_rates[band] != rates)
 397                 changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
 398         sta->sta.supp_rates[band] = rates;
 399
 400         if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 401                                               elems->ht_cap_elem, sta))
 402                 changed |= IEEE80211_RC_BW_CHANGED;
 403
 404         /* HT peer is operating 20MHz-only */
 405         if (elems->ht_operation &&
 406             !(elems->ht_operation->ht_param &
 407               IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
 408                 if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
 409                         changed |= IEEE80211_RC_BW_CHANGED;
 410                 sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
 411         }
 412
 413         if (insert)
 414                 rate_control_rate_init(sta);
 415         else
 416                 rate_control_rate_update(local, sband, sta, changed);
 417 out:
 418         spin_unlock_bh(&sta->lock);
 419 }
 420
 421 static struct sta_info *
 422 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
 423 {
 424         struct sta_info *sta;
 425
 426         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
 427                 return NULL;
 428
 429         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 430         if (!sta)
 431                 return NULL;
 432
 433         sta->plink_state = NL80211_PLINK_LISTEN;
 434         sta->sta.wme = true;
 435
 436         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 437         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 438         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 439
 440         return sta;
 441 }
 442
 443 static struct sta_info *
 444 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
 445                     struct ieee802_11_elems *elems)
 446 {
 447         struct sta_info *sta = NULL;
 448
 449         /* Userspace handles station allocation */
 450         if (sdata->u.mesh.user_mpm ||
 451             sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
 452                 cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 453                                                    elems->ie_start,
 454                                                    elems->total_len,
 455                                                    GFP_KERNEL);
 456         else
 457                 sta = __mesh_sta_info_alloc(sdata, addr);
 458
 459         return sta;
 460 }
 461
 462 /*
 463  * mesh_sta_info_get - return mesh sta info entry for @addr.
 464  *
 465  * @sdata: local meshif
 466  * @addr: peer's address
 467  * @elems: IEs from beacon or mesh peering frame.
 468  *
 469  * Return existing or newly allocated sta_info under RCU read lock.
 470  * (re)initialize with given IEs.
 471  */
 472 static struct sta_info *
 473 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
 474                   u8 *addr, struct ieee802_11_elems *elems) __acquires(RCU)
 475 {
 476         struct sta_info *sta = NULL;
 477
 478         rcu_read_lock();
 479         sta = sta_info_get(sdata, addr);
 480         if (sta) {
 481                 mesh_sta_info_init(sdata, sta, elems, false);
 482         } else {
 483                 rcu_read_unlock();
 484                 /* can't run atomic */
 485                 sta = mesh_sta_info_alloc(sdata, addr, elems);
 486                 if (!sta) {
 487                         rcu_read_lock();
 488                         return NULL;
 489                 }
 490
 491                 mesh_sta_info_init(sdata, sta, elems, true);
 492
 493                 if (sta_info_insert_rcu(sta))
 494                         return NULL;
 495         }
 496
 497         return sta;
 498 }
 499
 500 /*
 501  * mesh_neighbour_update - update or initialize new mesh neighbor.
 502  *
 503  * @sdata: local meshif
 504  * @addr: peer's address
 505  * @elems: IEs from beacon or mesh peering frame
 506  *
 507  * Initiates peering if appropriate.
 508  */
 509 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 510                            u8 *hw_addr,
 511                            struct ieee802_11_elems *elems)
 512 {
 513         struct sta_info *sta;
 514         u32 changed = 0;
 515
 516         sta = mesh_sta_info_get(sdata, hw_addr, elems);
 517         if (!sta)
 518                 goto out;
 519
 520         if (mesh_peer_accepts_plinks(elems) &&
 521             sta->plink_state == NL80211_PLINK_LISTEN &&
 522             sdata->u.mesh.accepting_plinks &&
 523             sdata->u.mesh.mshcfg.auto_open_plinks &&
 524             rssi_threshold_check(sdata, sta))
 525                 changed = mesh_plink_open(sta);
 526
 527         ieee80211_mps_frame_release(sta, elems);
 528 out:
 529         rcu_read_unlock();
 530         ieee80211_mbss_info_change_notify(sdata, changed);
 531 }
 532
 533 static void mesh_plink_timer(unsigned long data)
 534 {
 535         struct sta_info *sta;
 536         u16 reason = 0;
 537         struct ieee80211_sub_if_data *sdata;
 538         struct mesh_config *mshcfg;
 539         enum ieee80211_self_protected_actioncode action = 0;
 540
 541         /*
 542          * This STA is valid because sta_info_destroy() will
 543          * del_timer_sync() this timer after having made sure
 544          * it cannot be readded (by deleting the plink.)
 545          */
 546         sta = (struct sta_info *) data;
 547
 548         if (sta->sdata->local->quiescing)
 549                 return;
 550
 551         spin_lock_bh(&sta->lock);
 552
 553         /* If a timer fires just before a state transition on another CPU,
 554          * we may have already extended the timeout and changed state by the
 555          * time we've acquired the lock and arrived  here.  In that case,
 556          * skip this timer and wait for the new one.
 557          */
 558         if (time_before(jiffies, sta->plink_timer.expires)) {
 559                 mpl_dbg(sta->sdata,
 560                         "Ignoring timer for %pM in state %s (timer adjusted)",
 561                         sta->sta.addr, mplstates[sta->plink_state]);
 562                 spin_unlock_bh(&sta->lock);
 563                 return;
 564         }
 565
 566         /* del_timer() and handler may race when entering these states */
 567         if (sta->plink_state == NL80211_PLINK_LISTEN ||
 568             sta->plink_state == NL80211_PLINK_ESTAB) {
 569                 mpl_dbg(sta->sdata,
 570                         "Ignoring timer for %pM in state %s (timer deleted)",
 571                         sta->sta.addr, mplstates[sta->plink_state]);
 572                 spin_unlock_bh(&sta->lock);
 573                 return;
 574         }
 575
 576         mpl_dbg(sta->sdata,
 577                 "Mesh plink timer for %pM fired on state %s\n",
 578                 sta->sta.addr, mplstates[sta->plink_state]);
 579         sdata = sta->sdata;
 580         mshcfg = &sdata->u.mesh.mshcfg;
 581
 582         switch (sta->plink_state) {
 583         case NL80211_PLINK_OPN_RCVD:
 584         case NL80211_PLINK_OPN_SNT:
 585                 /* retry timer */
 586                 if (sta->plink_retries < mshcfg->dot11MeshMaxRetries) {
 587                         u32 rand;
 588                         mpl_dbg(sta->sdata,
 589                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 590                                 sta->sta.addr, sta->plink_retries,
 591                                 sta->plink_timeout);
 592                         get_random_bytes(&rand, sizeof(u32));
 593                         sta->plink_timeout = sta->plink_timeout +
 594                                              rand % sta->plink_timeout;
 595                         ++sta->plink_retries;
 596                         mod_plink_timer(sta, sta->plink_timeout);
 597                         action = WLAN_SP_MESH_PEERING_OPEN;
 598                         break;
 599                 }
 600                 reason = WLAN_REASON_MESH_MAX_RETRIES;
 601                 /* fall through on else */
 602         case NL80211_PLINK_CNF_RCVD:
 603                 /* confirm timer */
 604                 if (!reason)
 605                         reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
 606                 sta->plink_state = NL80211_PLINK_HOLDING;
 607                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 608                 action = WLAN_SP_MESH_PEERING_CLOSE;
 609                 break;
 610         case NL80211_PLINK_HOLDING:
 611                 /* holding timer */
 612                 del_timer(&sta->plink_timer);
 613                 mesh_plink_fsm_restart(sta);
 614                 break;
 615         default:
 616                 break;
 617         }
 618         spin_unlock_bh(&sta->lock);
 619         if (action)
 620                 mesh_plink_frame_tx(sdata, action, sta->sta.addr,
 621                                     sta->llid, sta->plid, reason);
 622 }
 623
 624 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 625 {
 626         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 627         sta->plink_timer.data = (unsigned long) sta;
 628         sta->plink_timer.function = mesh_plink_timer;
 629         sta->plink_timeout = timeout;
 630         add_timer(&sta->plink_timer);
 631 }
 632
 633 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
 634                         u16 llid)
 635 {
 636         struct ieee80211_local *local = sdata->local;
 637         bool in_use = false;
 638         struct sta_info *sta;
 639
 640         rcu_read_lock();
 641         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 642                 if (!memcmp(&sta->llid, &llid, sizeof(llid))) {
 643                         in_use = true;
 644                         break;
 645                 }
 646         }
 647         rcu_read_unlock();
 648
 649         return in_use;
 650 }
 651
 652 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 653 {
 654         u16 llid;
 655
 656         do {
 657                 get_random_bytes(&llid, sizeof(llid));
 658                 /* for mesh PS we still only have the AID range for TIM bits */
 659                 llid = (llid % IEEE80211_MAX_AID) + 1;
 660         } while (llid_in_use(sdata, llid));
 661
 662         return llid;
 663 }
 664
 665 u32 mesh_plink_open(struct sta_info *sta)
 666 {
 667         struct ieee80211_sub_if_data *sdata = sta->sdata;
 668         u32 changed;
 669
 670         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 671                 return 0;
 672
 673         spin_lock_bh(&sta->lock);
 674         sta->llid = mesh_get_new_llid(sdata);
 675         if (sta->plink_state != NL80211_PLINK_LISTEN &&
 676             sta->plink_state != NL80211_PLINK_BLOCKED) {
 677                 spin_unlock_bh(&sta->lock);
 678                 return 0;
 679         }
 680         sta->plink_state = NL80211_PLINK_OPN_SNT;
 681         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 682         spin_unlock_bh(&sta->lock);
 683         mpl_dbg(sdata,
 684                 "Mesh plink: starting establishment with %pM\n",
 685                 sta->sta.addr);
 686
 687         /* set the non-peer mode to active during peering */
 688         changed = ieee80211_mps_local_status_update(sdata);
 689
 690         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 691                             sta->sta.addr, sta->llid, 0, 0);
 692         return changed;
 693 }
 694
 695 u32 mesh_plink_block(struct sta_info *sta)
 696 {
 697         u32 changed;
 698
 699         spin_lock_bh(&sta->lock);
 700         changed = __mesh_plink_deactivate(sta);
 701         sta->plink_state = NL80211_PLINK_BLOCKED;
 702         spin_unlock_bh(&sta->lock);
 703
 704         return changed;
 705 }
 706
 707 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
 708                              struct sta_info *sta,
 709                              enum plink_event event)
 710 {
 711         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 712
 713         u16 reason = (event == CLS_ACPT) ?
 714                      WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
 715
 716         sta->reason = reason;
 717         sta->plink_state = NL80211_PLINK_HOLDING;
 718         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 719 }
 720
 721 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
 722                                 struct sta_info *sta)
 723 {
 724         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 725         u32 changed = 0;
 726
 727         del_timer(&sta->plink_timer);
 728         sta->plink_state = NL80211_PLINK_ESTAB;
 729         changed |= mesh_plink_inc_estab_count(sdata);
 730         changed |= mesh_set_ht_prot_mode(sdata);
 731         changed |= mesh_set_short_slot_time(sdata);
 732         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
 733         ieee80211_mps_sta_status_update(sta);
 734         changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
 735         return changed;
 736 }
 737
 738 /**
 739  * mesh_plink_fsm - step @sta MPM based on @event
 740  *
 741  * @sdata: interface
 742  * @sta: mesh neighbor
 743  * @event: peering event
 744  *
 745  * Return: changed MBSS flags
 746  */
 747 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
 748                           struct sta_info *sta, enum plink_event event)
 749 {
 750         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 751         enum ieee80211_self_protected_actioncode action = 0;
 752         u32 changed = 0;
 753
 754         mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
 755                 mplstates[sta->plink_state], mplevents[event]);
 756
 757         spin_lock_bh(&sta->lock);
 758         switch (sta->plink_state) {
 759         case NL80211_PLINK_LISTEN:
 760                 switch (event) {
 761                 case CLS_ACPT:
 762                         mesh_plink_fsm_restart(sta);
 763                         break;
 764                 case OPN_ACPT:
 765                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 766                         sta->llid = mesh_get_new_llid(sdata);
 767                         mesh_plink_timer_set(sta,
 768                                              mshcfg->dot11MeshRetryTimeout);
 769
 770                         /* set the non-peer mode to active during peering */
 771                         changed |= ieee80211_mps_local_status_update(sdata);
 772                         action = WLAN_SP_MESH_PEERING_OPEN;
 773                         break;
 774                 default:
 775                         break;
 776                 }
 777                 break;
 778         case NL80211_PLINK_OPN_SNT:
 779                 switch (event) {
 780                 case OPN_RJCT:
 781                 case CNF_RJCT:
 782                 case CLS_ACPT:
 783                         mesh_plink_close(sdata, sta, event);
 784                         action = WLAN_SP_MESH_PEERING_CLOSE;
 785                         break;
 786                 case OPN_ACPT:
 787                         /* retry timer is left untouched */
 788                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 789                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 790                         break;
 791                 case CNF_ACPT:
 792                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 793                         mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
 794                         break;
 795                 default:
 796                         break;
 797                 }
 798                 break;
 799         case NL80211_PLINK_OPN_RCVD:
 800                 switch (event) {
 801                 case OPN_RJCT:
 802                 case CNF_RJCT:
 803                 case CLS_ACPT:
 804                         mesh_plink_close(sdata, sta, event);
 805                         action = WLAN_SP_MESH_PEERING_CLOSE;
 806                         break;
 807                 case OPN_ACPT:
 808                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 809                         break;
 810                 case CNF_ACPT:
 811                         changed |= mesh_plink_establish(sdata, sta);
 812                         break;
 813                 default:
 814                         break;
 815                 }
 816                 break;
 817         case NL80211_PLINK_CNF_RCVD:
 818                 switch (event) {
 819                 case OPN_RJCT:
 820                 case CNF_RJCT:
 821                 case CLS_ACPT:
 822                         mesh_plink_close(sdata, sta, event);
 823                         action = WLAN_SP_MESH_PEERING_CLOSE;
 824                         break;
 825                 case OPN_ACPT:
 826                         changed |= mesh_plink_establish(sdata, sta);
 827                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 828                         break;
 829                 default:
 830                         break;
 831                 }
 832                 break;
 833         case NL80211_PLINK_ESTAB:
 834                 switch (event) {
 835                 case CLS_ACPT:
 836                         changed |= __mesh_plink_deactivate(sta);
 837                         changed |= mesh_set_ht_prot_mode(sdata);
 838                         changed |= mesh_set_short_slot_time(sdata);
 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                 default:
 846                         break;
 847                 }
 848                 break;
 849         case NL80211_PLINK_HOLDING:
 850                 switch (event) {
 851                 case CLS_ACPT:
 852                         del_timer(&sta->plink_timer);
 853                         mesh_plink_fsm_restart(sta);
 854                         break;
 855                 case OPN_ACPT:
 856                 case CNF_ACPT:
 857                 case OPN_RJCT:
 858                 case CNF_RJCT:
 859                         action = WLAN_SP_MESH_PEERING_CLOSE;
 860                         break;
 861                 default:
 862                         break;
 863                 }
 864                 break;
 865         default:
 866                 /* should not get here, PLINK_BLOCKED is dealt with at the
 867                  * beginning of the function
 868                  */
 869                 break;
 870         }
 871         spin_unlock_bh(&sta->lock);
 872         if (action) {
 873                 mesh_plink_frame_tx(sdata, action, sta->sta.addr,
 874                                     sta->llid, sta->plid, sta->reason);
 875
 876                 /* also send confirm in open case */
 877                 if (action == WLAN_SP_MESH_PEERING_OPEN) {
 878                         mesh_plink_frame_tx(sdata,
 879                                             WLAN_SP_MESH_PEERING_CONFIRM,
 880                                             sta->sta.addr, sta->llid,
 881                                             sta->plid, 0);
 882                 }
 883         }
 884
 885         return changed;
 886 }
 887
 888 /*
 889  * mesh_plink_get_event - get correct MPM event
 890  *
 891  * @sdata: interface
 892  * @sta: peer, leave NULL if processing a frame from a new suitable peer
 893  * @elems: peering management IEs
 894  * @ftype: frame type
 895  * @llid: peer's peer link ID
 896  * @plid: peer's local link ID
 897  *
 898  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
 899  * an error.
 900  */
 901 static enum plink_event
 902 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
 903                      struct sta_info *sta,
 904                      struct ieee802_11_elems *elems,
 905                      enum ieee80211_self_protected_actioncode ftype,
 906                      u16 llid, u16 plid)
 907 {
 908         enum plink_event event = PLINK_UNDEFINED;
 909         u8 ie_len = elems->peering_len;
 910         bool matches_local;
 911
 912         matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
 913                          mesh_matches_local(sdata, elems));
 914
 915         /* deny open request from non-matching peer */
 916         if (!matches_local && !sta) {
 917                 event = OPN_RJCT;
 918                 goto out;
 919         }
 920
 921         if (!sta) {
 922                 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
 923                         mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 924                         goto out;
 925                 }
 926                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 927                 if (!mesh_plink_free_count(sdata)) {
 928                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 929                         goto out;
 930                 }
 931         } else {
 932                 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
 933                         mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 934                         goto out;
 935                 }
 936                 if (sta->plink_state == NL80211_PLINK_BLOCKED)
 937                         goto out;
 938         }
 939
 940         /* new matching peer */
 941         if (!sta) {
 942                 event = OPN_ACPT;
 943                 goto out;
 944         }
 945
 946         switch (ftype) {
 947         case WLAN_SP_MESH_PEERING_OPEN:
 948                 if (!matches_local)
 949                         event = OPN_RJCT;
 950                 if (!mesh_plink_free_count(sdata) ||
 951                     (sta->plid && sta->plid != plid))
 952                         event = OPN_IGNR;
 953                 else
 954                         event = OPN_ACPT;
 955                 break;
 956         case WLAN_SP_MESH_PEERING_CONFIRM:
 957                 if (!matches_local)
 958                         event = CNF_RJCT;
 959                 if (!mesh_plink_free_count(sdata) ||
 960                     sta->llid != llid ||
 961                     (sta->plid && sta->plid != plid))
 962                         event = CNF_IGNR;
 963                 else
 964                         event = CNF_ACPT;
 965                 break;
 966         case WLAN_SP_MESH_PEERING_CLOSE:
 967                 if (sta->plink_state == NL80211_PLINK_ESTAB)
 968                         /* Do not check for llid or plid. This does not
 969                          * follow the standard but since multiple plinks
 970                          * per sta are not supported, it is necessary in
 971                          * order to avoid a livelock when MP A sees an
 972                          * establish peer link to MP B but MP B does not
 973                          * see it. This can be caused by a timeout in
 974                          * B's peer link establishment or B beign
 975                          * restarted.
 976                          */
 977                         event = CLS_ACPT;
 978                 else if (sta->plid != plid)
 979                         event = CLS_IGNR;
 980                 else if (ie_len == 8 && sta->llid != llid)
 981                         event = CLS_IGNR;
 982                 else
 983                         event = CLS_ACPT;
 984                 break;
 985         default:
 986                 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 987                 break;
 988         }
 989
 990 out:
 991         return event;
 992 }
 993
 994 static void
 995 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
 996                          struct ieee80211_mgmt *mgmt,
 997                          struct ieee802_11_elems *elems)
 998 {
 999
1000         struct sta_info *sta;
1001         enum plink_event event;
1002         enum ieee80211_self_protected_actioncode ftype;
1003         u32 changed = 0;
1004         u8 ie_len = elems->peering_len;
1005         u16 plid, llid = 0;
1006
1007         if (!elems->peering) {
1008                 mpl_dbg(sdata,
1009                         "Mesh plink: missing necessary peer link ie\n");
1010                 return;
1011         }
1012
1013         if (elems->rsn_len &&
1014             sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1015                 mpl_dbg(sdata,
1016                         "Mesh plink: can't establish link with secure peer\n");
1017                 return;
1018         }
1019
1020         ftype = mgmt->u.action.u.self_prot.action_code;
1021         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1022             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1023             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1024                                                         && ie_len != 8)) {
1025                 mpl_dbg(sdata,
1026                         "Mesh plink: incorrect plink ie length %d %d\n",
1027                         ftype, ie_len);
1028                 return;
1029         }
1030
1031         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1032             (!elems->mesh_id || !elems->mesh_config)) {
1033                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1034                 return;
1035         }
1036         /* Note the lines below are correct, the llid in the frame is the plid
1037          * from the point of view of this host.
1038          */
1039         plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1040         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1041             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1042                 llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1043
1044         /* WARNING: Only for sta pointer, is dropped & re-acquired */
1045         rcu_read_lock();
1046
1047         sta = sta_info_get(sdata, mgmt->sa);
1048
1049         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1050             !rssi_threshold_check(sdata, sta)) {
1051                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1052                         mgmt->sa);
1053                 goto unlock_rcu;
1054         }
1055
1056         /* Now we will figure out the appropriate event... */
1057         event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1058
1059         if (event == OPN_ACPT) {
1060                 rcu_read_unlock();
1061                 /* allocate sta entry if necessary and update info */
1062                 sta = mesh_sta_info_get(sdata, mgmt->sa, elems);
1063                 if (!sta) {
1064                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1065                         goto unlock_rcu;
1066                 }
1067                 sta->plid = plid;
1068         } else if (!sta && event == OPN_RJCT) {
1069                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
1070                                     mgmt->sa, 0, plid,
1071                                     WLAN_REASON_MESH_CONFIG);
1072                 goto unlock_rcu;
1073         } else if (!sta || event == PLINK_UNDEFINED) {
1074                 /* something went wrong */
1075                 goto unlock_rcu;
1076         }
1077
1078         /* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1079         if (!sta->plid && event == CNF_ACPT)
1080                 sta->plid = plid;
1081
1082         changed |= mesh_plink_fsm(sdata, sta, event);
1083
1084 unlock_rcu:
1085         rcu_read_unlock();
1086
1087         if (changed)
1088                 ieee80211_mbss_info_change_notify(sdata, changed);
1089 }
1090
1091 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1092                          struct ieee80211_mgmt *mgmt, size_t len,
1093                          struct ieee80211_rx_status *rx_status)
1094 {
1095         struct ieee802_11_elems elems;
1096         size_t baselen;
1097         u8 *baseaddr;
1098
1099         /* need action_code, aux */
1100         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1101                 return;
1102
1103         if (sdata->u.mesh.user_mpm)
1104                 /* userspace must register for these */
1105                 return;
1106
1107         if (is_multicast_ether_addr(mgmt->da)) {
1108                 mpl_dbg(sdata,
1109                         "Mesh plink: ignore frame from multicast address\n");
1110                 return;
1111         }
1112
1113         baseaddr = mgmt->u.action.u.self_prot.variable;
1114         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1115         if (mgmt->u.action.u.self_prot.action_code ==
1116                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
1117                 baseaddr += 4;
1118                 baselen += 4;
1119         }
1120         ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems);
1121         mesh_process_plink_frame(sdata, mgmt, &elems);
1122 }