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 nl80211_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 == NL80211_BAND_5GHZ) {
 104                 /* (IEEE 802.11-2012 19.4.5) */
 105                 short_slot = true;
 106                 goto out;
 107         } else if (band != NL80211_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 nl80211_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  * Mesh paths with this peer as next hop should be flushed
 335  * by the caller outside of plink_lock.
 336  *
 337  * Returns beacon changed flag if the beacon content changed.
 338  *
 339  * Locking: the caller must hold sta->mesh->plink_lock
 340  */
 341 static u32 __mesh_plink_deactivate(struct sta_info *sta)
 342 {
 343         struct ieee80211_sub_if_data *sdata = sta->sdata;
 344         u32 changed = 0;
 345
 346         lockdep_assert_held(&sta->mesh->plink_lock);
 347
 348         if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
 349                 changed = mesh_plink_dec_estab_count(sdata);
 350         sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 351
 352         ieee80211_mps_sta_status_update(sta);
 353         changed |= ieee80211_mps_set_sta_local_pm(sta,
 354                         NL80211_MESH_POWER_UNKNOWN);
 355
 356         return changed;
 357 }
 358
 359 /**
 360  * mesh_plink_deactivate - deactivate mesh peer link
 361  *
 362  * @sta: mesh peer link to deactivate
 363  *
 364  * All mesh paths with this peer as next hop will be flushed
 365  */
 366 u32 mesh_plink_deactivate(struct sta_info *sta)
 367 {
 368         struct ieee80211_sub_if_data *sdata = sta->sdata;
 369         u32 changed;
 370
 371         spin_lock_bh(&sta->mesh->plink_lock);
 372         changed = __mesh_plink_deactivate(sta);
 373         sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
 374         mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
 375                             sta->sta.addr, sta->mesh->llid, sta->mesh->plid,
 376                             sta->mesh->reason);
 377         spin_unlock_bh(&sta->mesh->plink_lock);
 378         mesh_path_flush_by_nexthop(sta);
 379
 380         return changed;
 381 }
 382
 383 static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
 384                                struct sta_info *sta,
 385                                struct ieee802_11_elems *elems, bool insert)
 386 {
 387         struct ieee80211_local *local = sdata->local;
 388         enum nl80211_band band = ieee80211_get_sdata_band(sdata);
 389         struct ieee80211_supported_band *sband;
 390         u32 rates, basic_rates = 0, changed = 0;
 391         enum ieee80211_sta_rx_bandwidth bw = sta->sta.bandwidth;
 392
 393         sband = local->hw.wiphy->bands[band];
 394         rates = ieee80211_sta_get_rates(sdata, elems, band, &basic_rates);
 395
 396         spin_lock_bh(&sta->mesh->plink_lock);
 397         sta->rx_stats.last_rx = jiffies;
 398
 399         /* rates and capabilities don't change during peering */
 400         if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
 401             sta->mesh->processed_beacon)
 402                 goto out;
 403         sta->mesh->processed_beacon = true;
 404
 405         if (sta->sta.supp_rates[band] != rates)
 406                 changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
 407         sta->sta.supp_rates[band] = rates;
 408
 409         if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 410                                               elems->ht_cap_elem, sta))
 411                 changed |= IEEE80211_RC_BW_CHANGED;
 412
 413         ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
 414                                             elems->vht_cap_elem, sta);
 415
 416         if (bw != sta->sta.bandwidth)
 417                 changed |= IEEE80211_RC_BW_CHANGED;
 418
 419         /* HT peer is operating 20MHz-only */
 420         if (elems->ht_operation &&
 421             !(elems->ht_operation->ht_param &
 422               IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
 423                 if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
 424                         changed |= IEEE80211_RC_BW_CHANGED;
 425                 sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
 426         }
 427
 428         if (insert)
 429                 rate_control_rate_init(sta);
 430         else
 431                 rate_control_rate_update(local, sband, sta, changed);
 432 out:
 433         spin_unlock_bh(&sta->mesh->plink_lock);
 434 }
 435
 436 static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
 437 {
 438         struct sta_info *sta;
 439         unsigned long *aid_map;
 440         int aid;
 441
 442         aid_map = kcalloc(BITS_TO_LONGS(IEEE80211_MAX_AID + 1),
 443                           sizeof(*aid_map), GFP_KERNEL);
 444         if (!aid_map)
 445                 return -ENOMEM;
 446
 447         /* reserve aid 0 for mcast indication */
 448         __set_bit(0, aid_map);
 449
 450         rcu_read_lock();
 451         list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
 452                 __set_bit(sta->sta.aid, aid_map);
 453         rcu_read_unlock();
 454
 455         aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
 456         kfree(aid_map);
 457
 458         if (aid > IEEE80211_MAX_AID)
 459                 return -ENOBUFS;
 460
 461         return aid;
 462 }
 463
 464 static struct sta_info *
 465 __mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
 466 {
 467         struct sta_info *sta;
 468         int aid;
 469
 470         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
 471                 return NULL;
 472
 473         aid = mesh_allocate_aid(sdata);
 474         if (aid < 0)
 475                 return NULL;
 476
 477         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 478         if (!sta)
 479                 return NULL;
 480
 481         sta->mesh->plink_state = NL80211_PLINK_LISTEN;
 482         sta->sta.wme = true;
 483         sta->sta.aid = aid;
 484
 485         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 486         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 487         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 488
 489         return sta;
 490 }
 491
 492 static struct sta_info *
 493 mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
 494                     struct ieee802_11_elems *elems)
 495 {
 496         struct sta_info *sta = NULL;
 497
 498         /* Userspace handles station allocation */
 499         if (sdata->u.mesh.user_mpm ||
 500             sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
 501                 cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 502                                                    elems->ie_start,
 503                                                    elems->total_len,
 504                                                    GFP_KERNEL);
 505         else
 506                 sta = __mesh_sta_info_alloc(sdata, addr);
 507
 508         return sta;
 509 }
 510
 511 /*
 512  * mesh_sta_info_get - return mesh sta info entry for @addr.
 513  *
 514  * @sdata: local meshif
 515  * @addr: peer's address
 516  * @elems: IEs from beacon or mesh peering frame.
 517  *
 518  * Return existing or newly allocated sta_info under RCU read lock.
 519  * (re)initialize with given IEs.
 520  */
 521 static struct sta_info *
 522 mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
 523                   u8 *addr, struct ieee802_11_elems *elems) __acquires(RCU)
 524 {
 525         struct sta_info *sta = NULL;
 526
 527         rcu_read_lock();
 528         sta = sta_info_get(sdata, addr);
 529         if (sta) {
 530                 mesh_sta_info_init(sdata, sta, elems, false);
 531         } else {
 532                 rcu_read_unlock();
 533                 /* can't run atomic */
 534                 sta = mesh_sta_info_alloc(sdata, addr, elems);
 535                 if (!sta) {
 536                         rcu_read_lock();
 537                         return NULL;
 538                 }
 539
 540                 mesh_sta_info_init(sdata, sta, elems, true);
 541
 542                 if (sta_info_insert_rcu(sta))
 543                         return NULL;
 544         }
 545
 546         return sta;
 547 }
 548
 549 /*
 550  * mesh_neighbour_update - update or initialize new mesh neighbor.
 551  *
 552  * @sdata: local meshif
 553  * @addr: peer's address
 554  * @elems: IEs from beacon or mesh peering frame
 555  *
 556  * Initiates peering if appropriate.
 557  */
 558 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 559                            u8 *hw_addr,
 560                            struct ieee802_11_elems *elems)
 561 {
 562         struct sta_info *sta;
 563         u32 changed = 0;
 564
 565         sta = mesh_sta_info_get(sdata, hw_addr, elems);
 566         if (!sta)
 567                 goto out;
 568
 569         if (mesh_peer_accepts_plinks(elems) &&
 570             sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
 571             sdata->u.mesh.accepting_plinks &&
 572             sdata->u.mesh.mshcfg.auto_open_plinks &&
 573             rssi_threshold_check(sdata, sta))
 574                 changed = mesh_plink_open(sta);
 575
 576         ieee80211_mps_frame_release(sta, elems);
 577 out:
 578         rcu_read_unlock();
 579         ieee80211_mbss_info_change_notify(sdata, changed);
 580 }
 581
 582 static void mesh_plink_timer(unsigned long data)
 583 {
 584         struct sta_info *sta;
 585         u16 reason = 0;
 586         struct ieee80211_sub_if_data *sdata;
 587         struct mesh_config *mshcfg;
 588         enum ieee80211_self_protected_actioncode action = 0;
 589
 590         /*
 591          * This STA is valid because sta_info_destroy() will
 592          * del_timer_sync() this timer after having made sure
 593          * it cannot be readded (by deleting the plink.)
 594          */
 595         sta = (struct sta_info *) data;
 596
 597         if (sta->sdata->local->quiescing)
 598                 return;
 599
 600         spin_lock_bh(&sta->mesh->plink_lock);
 601
 602         /* If a timer fires just before a state transition on another CPU,
 603          * we may have already extended the timeout and changed state by the
 604          * time we've acquired the lock and arrived  here.  In that case,
 605          * skip this timer and wait for the new one.
 606          */
 607         if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
 608                 mpl_dbg(sta->sdata,
 609                         "Ignoring timer for %pM in state %s (timer adjusted)",
 610                         sta->sta.addr, mplstates[sta->mesh->plink_state]);
 611                 spin_unlock_bh(&sta->mesh->plink_lock);
 612                 return;
 613         }
 614
 615         /* del_timer() and handler may race when entering these states */
 616         if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
 617             sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
 618                 mpl_dbg(sta->sdata,
 619                         "Ignoring timer for %pM in state %s (timer deleted)",
 620                         sta->sta.addr, mplstates[sta->mesh->plink_state]);
 621                 spin_unlock_bh(&sta->mesh->plink_lock);
 622                 return;
 623         }
 624
 625         mpl_dbg(sta->sdata,
 626                 "Mesh plink timer for %pM fired on state %s\n",
 627                 sta->sta.addr, mplstates[sta->mesh->plink_state]);
 628         sdata = sta->sdata;
 629         mshcfg = &sdata->u.mesh.mshcfg;
 630
 631         switch (sta->mesh->plink_state) {
 632         case NL80211_PLINK_OPN_RCVD:
 633         case NL80211_PLINK_OPN_SNT:
 634                 /* retry timer */
 635                 if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
 636                         u32 rand;
 637                         mpl_dbg(sta->sdata,
 638                                 "Mesh plink for %pM (retry, timeout): %d %d\n",
 639                                 sta->sta.addr, sta->mesh->plink_retries,
 640                                 sta->mesh->plink_timeout);
 641                         get_random_bytes(&rand, sizeof(u32));
 642                         sta->mesh->plink_timeout = sta->mesh->plink_timeout +
 643                                              rand % sta->mesh->plink_timeout;
 644                         ++sta->mesh->plink_retries;
 645                         mod_plink_timer(sta, sta->mesh->plink_timeout);
 646                         action = WLAN_SP_MESH_PEERING_OPEN;
 647                         break;
 648                 }
 649                 reason = WLAN_REASON_MESH_MAX_RETRIES;
 650                 /* fall through on else */
 651         case NL80211_PLINK_CNF_RCVD:
 652                 /* confirm timer */
 653                 if (!reason)
 654                         reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
 655                 sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 656                 mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 657                 action = WLAN_SP_MESH_PEERING_CLOSE;
 658                 break;
 659         case NL80211_PLINK_HOLDING:
 660                 /* holding timer */
 661                 del_timer(&sta->mesh->plink_timer);
 662                 mesh_plink_fsm_restart(sta);
 663                 break;
 664         default:
 665                 break;
 666         }
 667         spin_unlock_bh(&sta->mesh->plink_lock);
 668         if (action)
 669                 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 670                                     sta->mesh->llid, sta->mesh->plid, reason);
 671 }
 672
 673 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
 674 {
 675         sta->mesh->plink_timer.expires = jiffies + msecs_to_jiffies(timeout);
 676         sta->mesh->plink_timer.data = (unsigned long) sta;
 677         sta->mesh->plink_timer.function = mesh_plink_timer;
 678         sta->mesh->plink_timeout = timeout;
 679         add_timer(&sta->mesh->plink_timer);
 680 }
 681
 682 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
 683                         u16 llid)
 684 {
 685         struct ieee80211_local *local = sdata->local;
 686         bool in_use = false;
 687         struct sta_info *sta;
 688
 689         rcu_read_lock();
 690         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 691                 if (sdata != sta->sdata)
 692                         continue;
 693
 694                 if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
 695                         in_use = true;
 696                         break;
 697                 }
 698         }
 699         rcu_read_unlock();
 700
 701         return in_use;
 702 }
 703
 704 static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 705 {
 706         u16 llid;
 707
 708         do {
 709                 get_random_bytes(&llid, sizeof(llid));
 710         } while (llid_in_use(sdata, llid));
 711
 712         return llid;
 713 }
 714
 715 u32 mesh_plink_open(struct sta_info *sta)
 716 {
 717         struct ieee80211_sub_if_data *sdata = sta->sdata;
 718         u32 changed;
 719
 720         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 721                 return 0;
 722
 723         spin_lock_bh(&sta->mesh->plink_lock);
 724         sta->mesh->llid = mesh_get_new_llid(sdata);
 725         if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
 726             sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
 727                 spin_unlock_bh(&sta->mesh->plink_lock);
 728                 return 0;
 729         }
 730         sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
 731         mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 732         spin_unlock_bh(&sta->mesh->plink_lock);
 733         mpl_dbg(sdata,
 734                 "Mesh plink: starting establishment with %pM\n",
 735                 sta->sta.addr);
 736
 737         /* set the non-peer mode to active during peering */
 738         changed = ieee80211_mps_local_status_update(sdata);
 739
 740         mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
 741                             sta->sta.addr, sta->mesh->llid, 0, 0);
 742         return changed;
 743 }
 744
 745 u32 mesh_plink_block(struct sta_info *sta)
 746 {
 747         u32 changed;
 748
 749         spin_lock_bh(&sta->mesh->plink_lock);
 750         changed = __mesh_plink_deactivate(sta);
 751         sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 752         spin_unlock_bh(&sta->mesh->plink_lock);
 753         mesh_path_flush_by_nexthop(sta);
 754
 755         return changed;
 756 }
 757
 758 static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
 759                              struct sta_info *sta,
 760                              enum plink_event event)
 761 {
 762         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 763         u16 reason = (event == CLS_ACPT) ?
 764                      WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
 765
 766         sta->mesh->reason = reason;
 767         sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 768         mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 769 }
 770
 771 static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
 772                                 struct sta_info *sta)
 773 {
 774         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 775         u32 changed = 0;
 776
 777         del_timer(&sta->mesh->plink_timer);
 778         sta->mesh->plink_state = NL80211_PLINK_ESTAB;
 779         changed |= mesh_plink_inc_estab_count(sdata);
 780         changed |= mesh_set_ht_prot_mode(sdata);
 781         changed |= mesh_set_short_slot_time(sdata);
 782         mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
 783         ieee80211_mps_sta_status_update(sta);
 784         changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
 785         return changed;
 786 }
 787
 788 /**
 789  * mesh_plink_fsm - step @sta MPM based on @event
 790  *
 791  * @sdata: interface
 792  * @sta: mesh neighbor
 793  * @event: peering event
 794  *
 795  * Return: changed MBSS flags
 796  */
 797 static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
 798                           struct sta_info *sta, enum plink_event event)
 799 {
 800         struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 801         enum ieee80211_self_protected_actioncode action = 0;
 802         u32 changed = 0;
 803         bool flush = false;
 804
 805         mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
 806                 mplstates[sta->mesh->plink_state], mplevents[event]);
 807
 808         spin_lock_bh(&sta->mesh->plink_lock);
 809         switch (sta->mesh->plink_state) {
 810         case NL80211_PLINK_LISTEN:
 811                 switch (event) {
 812                 case CLS_ACPT:
 813                         mesh_plink_fsm_restart(sta);
 814                         break;
 815                 case OPN_ACPT:
 816                         sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 817                         sta->mesh->llid = mesh_get_new_llid(sdata);
 818                         mesh_plink_timer_set(sta,
 819                                              mshcfg->dot11MeshRetryTimeout);
 820
 821                         /* set the non-peer mode to active during peering */
 822                         changed |= ieee80211_mps_local_status_update(sdata);
 823                         action = WLAN_SP_MESH_PEERING_OPEN;
 824                         break;
 825                 default:
 826                         break;
 827                 }
 828                 break;
 829         case NL80211_PLINK_OPN_SNT:
 830                 switch (event) {
 831                 case OPN_RJCT:
 832                 case CNF_RJCT:
 833                 case CLS_ACPT:
 834                         mesh_plink_close(sdata, sta, event);
 835                         action = WLAN_SP_MESH_PEERING_CLOSE;
 836                         break;
 837                 case OPN_ACPT:
 838                         /* retry timer is left untouched */
 839                         sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 840                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 841                         break;
 842                 case CNF_ACPT:
 843                         sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
 844                         mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
 845                         break;
 846                 default:
 847                         break;
 848                 }
 849                 break;
 850         case NL80211_PLINK_OPN_RCVD:
 851                 switch (event) {
 852                 case OPN_RJCT:
 853                 case CNF_RJCT:
 854                 case CLS_ACPT:
 855                         mesh_plink_close(sdata, sta, event);
 856                         action = WLAN_SP_MESH_PEERING_CLOSE;
 857                         break;
 858                 case OPN_ACPT:
 859                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 860                         break;
 861                 case CNF_ACPT:
 862                         changed |= mesh_plink_establish(sdata, sta);
 863                         break;
 864                 default:
 865                         break;
 866                 }
 867                 break;
 868         case NL80211_PLINK_CNF_RCVD:
 869                 switch (event) {
 870                 case OPN_RJCT:
 871                 case CNF_RJCT:
 872                 case CLS_ACPT:
 873                         mesh_plink_close(sdata, sta, event);
 874                         action = WLAN_SP_MESH_PEERING_CLOSE;
 875                         break;
 876                 case OPN_ACPT:
 877                         changed |= mesh_plink_establish(sdata, sta);
 878                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 879                         break;
 880                 default:
 881                         break;
 882                 }
 883                 break;
 884         case NL80211_PLINK_ESTAB:
 885                 switch (event) {
 886                 case CLS_ACPT:
 887                         changed |= __mesh_plink_deactivate(sta);
 888                         changed |= mesh_set_ht_prot_mode(sdata);
 889                         changed |= mesh_set_short_slot_time(sdata);
 890                         mesh_plink_close(sdata, sta, event);
 891                         action = WLAN_SP_MESH_PEERING_CLOSE;
 892                         flush = true;
 893                         break;
 894                 case OPN_ACPT:
 895                         action = WLAN_SP_MESH_PEERING_CONFIRM;
 896                         break;
 897                 default:
 898                         break;
 899                 }
 900                 break;
 901         case NL80211_PLINK_HOLDING:
 902                 switch (event) {
 903                 case CLS_ACPT:
 904                         del_timer(&sta->mesh->plink_timer);
 905                         mesh_plink_fsm_restart(sta);
 906                         break;
 907                 case OPN_ACPT:
 908                 case CNF_ACPT:
 909                 case OPN_RJCT:
 910                 case CNF_RJCT:
 911                         action = WLAN_SP_MESH_PEERING_CLOSE;
 912                         break;
 913                 default:
 914                         break;
 915                 }
 916                 break;
 917         default:
 918                 /* should not get here, PLINK_BLOCKED is dealt with at the
 919                  * beginning of the function
 920                  */
 921                 break;
 922         }
 923         spin_unlock_bh(&sta->mesh->plink_lock);
 924         if (flush)
 925                 mesh_path_flush_by_nexthop(sta);
 926         if (action) {
 927                 mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 928                                     sta->mesh->llid, sta->mesh->plid,
 929                                     sta->mesh->reason);
 930
 931                 /* also send confirm in open case */
 932                 if (action == WLAN_SP_MESH_PEERING_OPEN) {
 933                         mesh_plink_frame_tx(sdata, sta,
 934                                             WLAN_SP_MESH_PEERING_CONFIRM,
 935                                             sta->sta.addr, sta->mesh->llid,
 936                                             sta->mesh->plid, 0);
 937                 }
 938         }
 939
 940         return changed;
 941 }
 942
 943 /*
 944  * mesh_plink_get_event - get correct MPM event
 945  *
 946  * @sdata: interface
 947  * @sta: peer, leave NULL if processing a frame from a new suitable peer
 948  * @elems: peering management IEs
 949  * @ftype: frame type
 950  * @llid: peer's peer link ID
 951  * @plid: peer's local link ID
 952  *
 953  * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
 954  * an error.
 955  */
 956 static enum plink_event
 957 mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
 958                      struct sta_info *sta,
 959                      struct ieee802_11_elems *elems,
 960                      enum ieee80211_self_protected_actioncode ftype,
 961                      u16 llid, u16 plid)
 962 {
 963         enum plink_event event = PLINK_UNDEFINED;
 964         u8 ie_len = elems->peering_len;
 965         bool matches_local;
 966
 967         matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
 968                          mesh_matches_local(sdata, elems));
 969
 970         /* deny open request from non-matching peer */
 971         if (!matches_local && !sta) {
 972                 event = OPN_RJCT;
 973                 goto out;
 974         }
 975
 976         if (!sta) {
 977                 if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
 978                         mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 979                         goto out;
 980                 }
 981                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 982                 if (!mesh_plink_free_count(sdata)) {
 983                         mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 984                         goto out;
 985                 }
 986
 987                 /* new matching peer */
 988                 event = OPN_ACPT;
 989                 goto out;
 990         } else {
 991                 if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
 992                         mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 993                         goto out;
 994                 }
 995                 if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
 996                         goto out;
 997         }
 998
 999         switch (ftype) {
1000         case WLAN_SP_MESH_PEERING_OPEN:
1001                 if (!matches_local)
1002                         event = OPN_RJCT;
1003                 if (!mesh_plink_free_count(sdata) ||
1004                     (sta->mesh->plid && sta->mesh->plid != plid))
1005                         event = OPN_IGNR;
1006                 else
1007                         event = OPN_ACPT;
1008                 break;
1009         case WLAN_SP_MESH_PEERING_CONFIRM:
1010                 if (!matches_local)
1011                         event = CNF_RJCT;
1012                 if (!mesh_plink_free_count(sdata) ||
1013                     sta->mesh->llid != llid ||
1014                     (sta->mesh->plid && sta->mesh->plid != plid))
1015                         event = CNF_IGNR;
1016                 else
1017                         event = CNF_ACPT;
1018                 break;
1019         case WLAN_SP_MESH_PEERING_CLOSE:
1020                 if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1021                         /* Do not check for llid or plid. This does not
1022                          * follow the standard but since multiple plinks
1023                          * per sta are not supported, it is necessary in
1024                          * order to avoid a livelock when MP A sees an
1025                          * establish peer link to MP B but MP B does not
1026                          * see it. This can be caused by a timeout in
1027                          * B's peer link establishment or B beign
1028                          * restarted.
1029                          */
1030                         event = CLS_ACPT;
1031                 else if (sta->mesh->plid != plid)
1032                         event = CLS_IGNR;
1033                 else if (ie_len == 8 && sta->mesh->llid != llid)
1034                         event = CLS_IGNR;
1035                 else
1036                         event = CLS_ACPT;
1037                 break;
1038         default:
1039                 mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1040                 break;
1041         }
1042
1043 out:
1044         return event;
1045 }
1046
1047 static void
1048 mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1049                          struct ieee80211_mgmt *mgmt,
1050                          struct ieee802_11_elems *elems)
1051 {
1052
1053         struct sta_info *sta;
1054         enum plink_event event;
1055         enum ieee80211_self_protected_actioncode ftype;
1056         u32 changed = 0;
1057         u8 ie_len = elems->peering_len;
1058         u16 plid, llid = 0;
1059
1060         if (!elems->peering) {
1061                 mpl_dbg(sdata,
1062                         "Mesh plink: missing necessary peer link ie\n");
1063                 return;
1064         }
1065
1066         if (elems->rsn_len &&
1067             sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1068                 mpl_dbg(sdata,
1069                         "Mesh plink: can't establish link with secure peer\n");
1070                 return;
1071         }
1072
1073         ftype = mgmt->u.action.u.self_prot.action_code;
1074         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1075             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1076             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1077                                                         && ie_len != 8)) {
1078                 mpl_dbg(sdata,
1079                         "Mesh plink: incorrect plink ie length %d %d\n",
1080                         ftype, ie_len);
1081                 return;
1082         }
1083
1084         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1085             (!elems->mesh_id || !elems->mesh_config)) {
1086                 mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1087                 return;
1088         }
1089         /* Note the lines below are correct, the llid in the frame is the plid
1090          * from the point of view of this host.
1091          */
1092         plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1093         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1094             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1095                 llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1096
1097         /* WARNING: Only for sta pointer, is dropped & re-acquired */
1098         rcu_read_lock();
1099
1100         sta = sta_info_get(sdata, mgmt->sa);
1101
1102         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1103             !rssi_threshold_check(sdata, sta)) {
1104                 mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1105                         mgmt->sa);
1106                 goto unlock_rcu;
1107         }
1108
1109         /* Now we will figure out the appropriate event... */
1110         event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1111
1112         if (event == OPN_ACPT) {
1113                 rcu_read_unlock();
1114                 /* allocate sta entry if necessary and update info */
1115                 sta = mesh_sta_info_get(sdata, mgmt->sa, elems);
1116                 if (!sta) {
1117                         mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1118                         goto unlock_rcu;
1119                 }
1120                 sta->mesh->plid = plid;
1121         } else if (!sta && event == OPN_RJCT) {
1122                 mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1123                                     mgmt->sa, 0, plid,
1124                                     WLAN_REASON_MESH_CONFIG);
1125                 goto unlock_rcu;
1126         } else if (!sta || event == PLINK_UNDEFINED) {
1127                 /* something went wrong */
1128                 goto unlock_rcu;
1129         }
1130
1131         if (event == CNF_ACPT) {
1132                 /* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1133                 if (!sta->mesh->plid)
1134                         sta->mesh->plid = plid;
1135
1136                 sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1137         }
1138
1139         changed |= mesh_plink_fsm(sdata, sta, event);
1140
1141 unlock_rcu:
1142         rcu_read_unlock();
1143
1144         if (changed)
1145                 ieee80211_mbss_info_change_notify(sdata, changed);
1146 }
1147
1148 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1149                          struct ieee80211_mgmt *mgmt, size_t len,
1150                          struct ieee80211_rx_status *rx_status)
1151 {
1152         struct ieee802_11_elems elems;
1153         size_t baselen;
1154         u8 *baseaddr;
1155
1156         /* need action_code, aux */
1157         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1158                 return;
1159
1160         if (sdata->u.mesh.user_mpm)
1161                 /* userspace must register for these */
1162                 return;
1163
1164         if (is_multicast_ether_addr(mgmt->da)) {
1165                 mpl_dbg(sdata,
1166                         "Mesh plink: ignore frame from multicast address\n");
1167                 return;
1168         }
1169
1170         baseaddr = mgmt->u.action.u.self_prot.variable;
1171         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1172         if (mgmt->u.action.u.self_prot.action_code ==
1173                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
1174                 baseaddr += 4;
1175                 baselen += 4;
1176
1177                 if (baselen > len)
1178                         return;
1179         }
1180         ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems);
1181         mesh_process_plink_frame(sdata, mgmt, &elems);
1182 }