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 #ifdef CONFIG_MAC80211_VERBOSE_MPL_DEBUG
  17 #define mpl_dbg(fmt, args...)   printk(KERN_DEBUG fmt, ##args)
  18 #else
  19 #define mpl_dbg(fmt, args...)   do { (void)(0); } while (0)
  20 #endif
  21
  22 #define PLINK_GET_LLID(p) (p + 2)
  23 #define PLINK_GET_PLID(p) (p + 4)
  24
  25 #define mod_plink_timer(s, t) (mod_timer(&s->plink_timer, \
  26                                 jiffies + HZ * t / 1000))
  27
  28 #define dot11MeshMaxRetries(s) (s->u.mesh.mshcfg.dot11MeshMaxRetries)
  29 #define dot11MeshRetryTimeout(s) (s->u.mesh.mshcfg.dot11MeshRetryTimeout)
  30 #define dot11MeshConfirmTimeout(s) (s->u.mesh.mshcfg.dot11MeshConfirmTimeout)
  31 #define dot11MeshHoldingTimeout(s) (s->u.mesh.mshcfg.dot11MeshHoldingTimeout)
  32 #define dot11MeshMaxPeerLinks(s) (s->u.mesh.mshcfg.dot11MeshMaxPeerLinks)
  33
  34 /* We only need a valid sta if user configured a minimum rssi_threshold. */
  35 #define rssi_threshold_check(sta, sdata) \
  36                 (sdata->u.mesh.mshcfg.rssi_threshold == 0 ||\
  37                 (sta && (s8) -ewma_read(&sta->avg_signal) > \
  38                 sdata->u.mesh.mshcfg.rssi_threshold))
  39
  40 enum plink_event {
  41         PLINK_UNDEFINED,
  42         OPN_ACPT,
  43         OPN_RJCT,
  44         OPN_IGNR,
  45         CNF_ACPT,
  46         CNF_RJCT,
  47         CNF_IGNR,
  48         CLS_ACPT,
  49         CLS_IGNR
  50 };
  51
  52 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
  53                 enum ieee80211_self_protected_actioncode action,
  54                 u8 *da, __le16 llid, __le16 plid, __le16 reason);
  55
  56 static inline
  57 void mesh_plink_inc_estab_count(struct ieee80211_sub_if_data *sdata)
  58 {
  59         atomic_inc(&sdata->u.mesh.mshstats.estab_plinks);
  60         mesh_accept_plinks_update(sdata);
  61 }
  62
  63 static inline
  64 void mesh_plink_dec_estab_count(struct ieee80211_sub_if_data *sdata)
  65 {
  66         atomic_dec(&sdata->u.mesh.mshstats.estab_plinks);
  67         mesh_accept_plinks_update(sdata);
  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  * Allocate mesh sta entry and insert into station table
  86  */
  87 static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
  88                                          u8 *hw_addr)
  89 {
  90         struct sta_info *sta;
  91
  92         if (sdata->local->num_sta >= MESH_MAX_PLINKS)
  93                 return NULL;
  94
  95         sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
  96         if (!sta)
  97                 return NULL;
  98
  99         sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 100         sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 101         sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 102
 103         set_sta_flag(sta, WLAN_STA_WME);
 104
 105         return sta;
 106 }
 107
 108 /** mesh_set_ht_prot_mode - set correct HT protection mode
 109  *
 110  * Section 9.23.3.5 of IEEE 80211s standard describes the protection rules for
 111  * HT mesh STA in a MBSS. Three HT protection modes are supported for now,
 112  * non-HT mixed mode, 20MHz-protection and no-protection mode. non-HT mixed
 113  * mode is selected if any non-HT peers are present in our MBSS.
 114  * 20MHz-protection mode is selected if all peers in our 20/40MHz MBSS support
 115  * HT and atleast one HT20 peer is present. Otherwise no-protection mode is
 116  * selected.
 117  */
 118 static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 119 {
 120         struct ieee80211_local *local = sdata->local;
 121         struct sta_info *sta;
 122         u32 changed = 0;
 123         u16 ht_opmode;
 124         bool non_ht_sta = false, ht20_sta = false;
 125
 126         if (local->_oper_channel_type == NL80211_CHAN_NO_HT)
 127                 return 0;
 128
 129         rcu_read_lock();
 130         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 131                 if (sdata == sta->sdata &&
 132                     sta->plink_state == NL80211_PLINK_ESTAB) {
 133                         switch (sta->ch_type) {
 134                         case NL80211_CHAN_NO_HT:
 135                                 mpl_dbg("mesh_plink %pM: nonHT sta (%pM) is present",
 136                                         sdata->vif.addr, sta->sta.addr);
 137                                 non_ht_sta = true;
 138                                 goto out;
 139                         case NL80211_CHAN_HT20:
 140                                 mpl_dbg("mesh_plink %pM: HT20 sta (%pM) is present",
 141                                         sdata->vif.addr, sta->sta.addr);
 142                                 ht20_sta = true;
 143                         default:
 144                                 break;
 145                         }
 146                 }
 147         }
 148 out:
 149         rcu_read_unlock();
 150
 151         if (non_ht_sta)
 152                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 153         else if (ht20_sta && local->_oper_channel_type > NL80211_CHAN_HT20)
 154                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 155         else
 156                 ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 157
 158         if (sdata->vif.bss_conf.ht_operation_mode != ht_opmode) {
 159                 sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 160                 sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 161                 changed = BSS_CHANGED_HT;
 162                 mpl_dbg("mesh_plink %pM: protection mode changed to %d",
 163                         sdata->vif.addr, ht_opmode);
 164         }
 165
 166         return changed;
 167 }
 168
 169 /**
 170  * __mesh_plink_deactivate - deactivate mesh peer link
 171  *
 172  * @sta: mesh peer link to deactivate
 173  *
 174  * All mesh paths with this peer as next hop will be flushed
 175  *
 176  * Locking: the caller must hold sta->lock
 177  */
 178 static bool __mesh_plink_deactivate(struct sta_info *sta)
 179 {
 180         struct ieee80211_sub_if_data *sdata = sta->sdata;
 181         bool deactivated = false;
 182
 183         if (sta->plink_state == NL80211_PLINK_ESTAB) {
 184                 mesh_plink_dec_estab_count(sdata);
 185                 deactivated = true;
 186         }
 187         sta->plink_state = NL80211_PLINK_BLOCKED;
 188         mesh_path_flush_by_nexthop(sta);
 189
 190         return deactivated;
 191 }
 192
 193 /**
 194  * mesh_plink_deactivate - deactivate mesh peer link
 195  *
 196  * @sta: mesh peer link to deactivate
 197  *
 198  * All mesh paths with this peer as next hop will be flushed
 199  */
 200 void mesh_plink_deactivate(struct sta_info *sta)
 201 {
 202         struct ieee80211_sub_if_data *sdata = sta->sdata;
 203         bool deactivated;
 204
 205         spin_lock_bh(&sta->lock);
 206         deactivated = __mesh_plink_deactivate(sta);
 207         sta->reason = cpu_to_le16(WLAN_REASON_MESH_PEER_CANCELED);
 208         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 209                             sta->sta.addr, sta->llid, sta->plid,
 210                             sta->reason);
 211         spin_unlock_bh(&sta->lock);
 212
 213         if (deactivated)
 214                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 215 }
 216
 217 static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 218                 enum ieee80211_self_protected_actioncode action,
 219                 u8 *da, __le16 llid, __le16 plid, __le16 reason) {
 220         struct ieee80211_local *local = sdata->local;
 221         struct sk_buff *skb;
 222         struct ieee80211_mgmt *mgmt;
 223         bool include_plid = false;
 224         u16 peering_proto = 0;
 225         u8 *pos, ie_len = 4;
 226         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 227                       sizeof(mgmt->u.action.u.self_prot);
 228
 229         skb = dev_alloc_skb(local->tx_headroom +
 230                             hdr_len +
 231                             2 + /* capability info */
 232                             2 + /* AID */
 233                             2 + 8 + /* supported rates */
 234                             2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 235                             2 + sdata->u.mesh.mesh_id_len +
 236                             2 + sizeof(struct ieee80211_meshconf_ie) +
 237                             2 + sizeof(struct ieee80211_ht_cap) +
 238                             2 + sizeof(struct ieee80211_ht_operation) +
 239                             2 + 8 + /* peering IE */
 240                             sdata->u.mesh.ie_len);
 241         if (!skb)
 242                 return -1;
 243         skb_reserve(skb, local->tx_headroom);
 244         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 245         memset(mgmt, 0, hdr_len);
 246         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 247                                           IEEE80211_STYPE_ACTION);
 248         memcpy(mgmt->da, da, ETH_ALEN);
 249         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 250         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 251         mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 252         mgmt->u.action.u.self_prot.action_code = action;
 253
 254         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 255                 /* capability info */
 256                 pos = skb_put(skb, 2);
 257                 memset(pos, 0, 2);
 258                 if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 259                         /* AID */
 260                         pos = skb_put(skb, 2);
 261                         memcpy(pos + 2, &plid, 2);
 262                 }
 263                 if (ieee80211_add_srates_ie(&sdata->vif, skb, true) ||
 264                     ieee80211_add_ext_srates_ie(&sdata->vif, skb, true) ||
 265                     mesh_add_rsn_ie(skb, sdata) ||
 266                     mesh_add_meshid_ie(skb, sdata) ||
 267                     mesh_add_meshconf_ie(skb, sdata))
 268                         return -1;
 269         } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 270                 if (mesh_add_meshid_ie(skb, sdata))
 271                         return -1;
 272         }
 273
 274         /* Add Mesh Peering Management element */
 275         switch (action) {
 276         case WLAN_SP_MESH_PEERING_OPEN:
 277                 break;
 278         case WLAN_SP_MESH_PEERING_CONFIRM:
 279                 ie_len += 2;
 280                 include_plid = true;
 281                 break;
 282         case WLAN_SP_MESH_PEERING_CLOSE:
 283                 if (plid) {
 284                         ie_len += 2;
 285                         include_plid = true;
 286                 }
 287                 ie_len += 2;    /* reason code */
 288                 break;
 289         default:
 290                 return -EINVAL;
 291         }
 292
 293         if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 294                 return -ENOMEM;
 295
 296         pos = skb_put(skb, 2 + ie_len);
 297         *pos++ = WLAN_EID_PEER_MGMT;
 298         *pos++ = ie_len;
 299         memcpy(pos, &peering_proto, 2);
 300         pos += 2;
 301         memcpy(pos, &llid, 2);
 302         pos += 2;
 303         if (include_plid) {
 304                 memcpy(pos, &plid, 2);
 305                 pos += 2;
 306         }
 307         if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 308                 memcpy(pos, &reason, 2);
 309                 pos += 2;
 310         }
 311
 312         if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 313                 if (mesh_add_ht_cap_ie(skb, sdata) ||
 314                     mesh_add_ht_oper_ie(skb, sdata))
 315                         return -1;
 316         }
 317
 318         if (mesh_add_vendor_ies(skb, sdata))
 319                 return -1;
 320
 321         ieee80211_tx_skb(sdata, skb);
 322         return 0;
 323 }
 324
 325 /* mesh_peer_init - initialize new mesh peer and return resulting sta_info
 326  *
 327  * @sdata: local meshif
 328  * @addr: peer's address
 329  * @elems: IEs from beacon or mesh peering frame
 330  *
 331  * call under RCU
 332  */
 333 static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata,
 334                                        u8 *addr,
 335                                        struct ieee802_11_elems *elems)
 336 {
 337         struct ieee80211_local *local = sdata->local;
 338         enum ieee80211_band band = local->oper_channel->band;
 339         struct ieee80211_supported_band *sband;
 340         u32 rates, basic_rates = 0;
 341         struct sta_info *sta;
 342         bool insert = false;
 343
 344         sband = local->hw.wiphy->bands[band];
 345         rates = ieee80211_sta_get_rates(local, elems, band, &basic_rates);
 346
 347         sta = sta_info_get(sdata, addr);
 348         if (!sta) {
 349                 sta = mesh_plink_alloc(sdata, addr);
 350                 if (!sta)
 351                         return NULL;
 352                 insert = true;
 353         }
 354
 355         spin_lock_bh(&sta->lock);
 356         sta->last_rx = jiffies;
 357         sta->sta.supp_rates[band] = rates;
 358         if (elems->ht_cap_elem &&
 359             sdata->local->_oper_channel_type != NL80211_CHAN_NO_HT)
 360                 ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 361                                                   elems->ht_cap_elem,
 362                                                   &sta->sta.ht_cap);
 363         else
 364                 memset(&sta->sta.ht_cap, 0, sizeof(sta->sta.ht_cap));
 365
 366         if (elems->ht_operation) {
 367                 if (!(elems->ht_operation->ht_param &
 368                       IEEE80211_HT_PARAM_CHAN_WIDTH_ANY))
 369                         sta->sta.ht_cap.cap &=
 370                                             ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 371                 sta->ch_type =
 372                         ieee80211_ht_oper_to_channel_type(elems->ht_operation);
 373         }
 374
 375         rate_control_rate_init(sta);
 376         spin_unlock_bh(&sta->lock);
 377
 378         if (insert && sta_info_insert(sta))
 379                 return NULL;
 380
 381         return sta;
 382 }
 383
 384 void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 385                            u8 *hw_addr,
 386                            struct ieee802_11_elems *elems)
 387 {
 388         struct sta_info *sta;
 389
 390         /* Userspace handles peer allocation when security is enabled */
 391         if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
 392                 cfg80211_notify_new_peer_candidate(sdata->dev, hw_addr,
 393                                                    elems->ie_start,
 394                                                    elems->total_len,
 395                                                    GFP_KERNEL);
 396                 return;
 397         }
 398
 399         rcu_read_lock();
 400         sta = mesh_peer_init(sdata, hw_addr, elems);
 401         if (!sta)
 402                 goto out;
 403
 404         if (mesh_peer_accepts_plinks(elems) &&
 405             sta->plink_state == NL80211_PLINK_LISTEN &&
 406             sdata->u.mesh.accepting_plinks &&
 407             sdata->u.mesh.mshcfg.auto_open_plinks &&
 408             rssi_threshold_check(sta, sdata))
 409                 mesh_plink_open(sta);
 410
 411 out:
 412         rcu_read_unlock();
 413 }
 414
 415 static void mesh_plink_timer(unsigned long data)
 416 {
 417         struct sta_info *sta;
 418         __le16 llid, plid, reason;
 419         struct ieee80211_sub_if_data *sdata;
 420
 421         /*
 422          * This STA is valid because sta_info_destroy() will
 423          * del_timer_sync() this timer after having made sure
 424          * it cannot be readded (by deleting the plink.)
 425          */
 426         sta = (struct sta_info *) data;
 427
 428         if (sta->sdata->local->quiescing) {
 429                 sta->plink_timer_was_running = true;
 430                 return;
 431         }
 432
 433         spin_lock_bh(&sta->lock);
 434         if (sta->ignore_plink_timer) {
 435                 sta->ignore_plink_timer = false;
 436                 spin_unlock_bh(&sta->lock);
 437                 return;
 438         }
 439         mpl_dbg("Mesh plink timer for %pM fired on state %d\n",
 440                 sta->sta.addr, sta->plink_state);
 441         reason = 0;
 442         llid = sta->llid;
 443         plid = sta->plid;
 444         sdata = sta->sdata;
 445
 446         switch (sta->plink_state) {
 447         case NL80211_PLINK_OPN_RCVD:
 448         case NL80211_PLINK_OPN_SNT:
 449                 /* retry timer */
 450                 if (sta->plink_retries < dot11MeshMaxRetries(sdata)) {
 451                         u32 rand;
 452                         mpl_dbg("Mesh plink for %pM (retry, timeout): %d %d\n",
 453                                 sta->sta.addr, sta->plink_retries,
 454                                 sta->plink_timeout);
 455                         get_random_bytes(&rand, sizeof(u32));
 456                         sta->plink_timeout = sta->plink_timeout +
 457                                              rand % sta->plink_timeout;
 458                         ++sta->plink_retries;
 459                         mod_plink_timer(sta, sta->plink_timeout);
 460                         spin_unlock_bh(&sta->lock);
 461                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 462                                             sta->sta.addr, llid, 0, 0);
 463                         break;
 464                 }
 465                 reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);
 466                 /* fall through on else */
 467         case NL80211_PLINK_CNF_RCVD:
 468                 /* confirm timer */
 469                 if (!reason)
 470                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);
 471                 sta->plink_state = NL80211_PLINK_HOLDING;
 472                 mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 473                 spin_unlock_bh(&sta->lock);
 474                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 475                                     sta->sta.addr, llid, plid, reason);
 476                 break;
 477         case NL80211_PLINK_HOLDING:
 478                 /* holding timer */
 479                 del_timer(&sta->plink_timer);
 480                 mesh_plink_fsm_restart(sta);
 481                 spin_unlock_bh(&sta->lock);
 482                 break;
 483         default:
 484                 spin_unlock_bh(&sta->lock);
 485                 break;
 486         }
 487 }
 488
 489 #ifdef CONFIG_PM
 490 void mesh_plink_quiesce(struct sta_info *sta)
 491 {
 492         if (del_timer_sync(&sta->plink_timer))
 493                 sta->plink_timer_was_running = true;
 494 }
 495
 496 void mesh_plink_restart(struct sta_info *sta)
 497 {
 498         if (sta->plink_timer_was_running) {
 499                 add_timer(&sta->plink_timer);
 500                 sta->plink_timer_was_running = false;
 501         }
 502 }
 503 #endif
 504
 505 static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 506 {
 507         sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 508         sta->plink_timer.data = (unsigned long) sta;
 509         sta->plink_timer.function = mesh_plink_timer;
 510         sta->plink_timeout = timeout;
 511         add_timer(&sta->plink_timer);
 512 }
 513
 514 int mesh_plink_open(struct sta_info *sta)
 515 {
 516         __le16 llid;
 517         struct ieee80211_sub_if_data *sdata = sta->sdata;
 518
 519         if (!test_sta_flag(sta, WLAN_STA_AUTH))
 520                 return -EPERM;
 521
 522         spin_lock_bh(&sta->lock);
 523         get_random_bytes(&llid, 2);
 524         sta->llid = llid;
 525         if (sta->plink_state != NL80211_PLINK_LISTEN) {
 526                 spin_unlock_bh(&sta->lock);
 527                 return -EBUSY;
 528         }
 529         sta->plink_state = NL80211_PLINK_OPN_SNT;
 530         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 531         spin_unlock_bh(&sta->lock);
 532         mpl_dbg("Mesh plink: starting establishment with %pM\n",
 533                 sta->sta.addr);
 534
 535         return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 536                                    sta->sta.addr, llid, 0, 0);
 537 }
 538
 539 void mesh_plink_block(struct sta_info *sta)
 540 {
 541         struct ieee80211_sub_if_data *sdata = sta->sdata;
 542         bool deactivated;
 543
 544         spin_lock_bh(&sta->lock);
 545         deactivated = __mesh_plink_deactivate(sta);
 546         sta->plink_state = NL80211_PLINK_BLOCKED;
 547         spin_unlock_bh(&sta->lock);
 548
 549         if (deactivated)
 550                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 551 }
 552
 553
 554 void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,
 555                          size_t len, struct ieee80211_rx_status *rx_status)
 556 {
 557         struct ieee802_11_elems elems;
 558         struct sta_info *sta;
 559         enum plink_event event;
 560         enum ieee80211_self_protected_actioncode ftype;
 561         size_t baselen;
 562         bool matches_local = true;
 563         u8 ie_len;
 564         u8 *baseaddr;
 565         u32 changed = 0;
 566         __le16 plid, llid, reason;
 567 #ifdef CONFIG_MAC80211_VERBOSE_MPL_DEBUG
 568         static const char *mplstates[] = {
 569                 [NL80211_PLINK_LISTEN] = "LISTEN",
 570                 [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 571                 [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 572                 [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 573                 [NL80211_PLINK_ESTAB] = "ESTAB",
 574                 [NL80211_PLINK_HOLDING] = "HOLDING",
 575                 [NL80211_PLINK_BLOCKED] = "BLOCKED"
 576         };
 577 #endif
 578
 579         /* need action_code, aux */
 580         if (len < IEEE80211_MIN_ACTION_SIZE + 3)
 581                 return;
 582
 583         if (is_multicast_ether_addr(mgmt->da)) {
 584                 mpl_dbg("Mesh plink: ignore frame from multicast address");
 585                 return;
 586         }
 587
 588         baseaddr = mgmt->u.action.u.self_prot.variable;
 589         baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
 590         if (mgmt->u.action.u.self_prot.action_code ==
 591                                                 WLAN_SP_MESH_PEERING_CONFIRM) {
 592                 baseaddr += 4;
 593                 baselen += 4;
 594         }
 595         ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
 596         if (!elems.peering) {
 597                 mpl_dbg("Mesh plink: missing necessary peer link ie\n");
 598                 return;
 599         }
 600         if (elems.rsn_len &&
 601                         sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
 602                 mpl_dbg("Mesh plink: can't establish link with secure peer\n");
 603                 return;
 604         }
 605
 606         ftype = mgmt->u.action.u.self_prot.action_code;
 607         ie_len = elems.peering_len;
 608         if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
 609             (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
 610             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
 611                                                         && ie_len != 8)) {
 612                 mpl_dbg("Mesh plink: incorrect plink ie length %d %d\n",
 613                     ftype, ie_len);
 614                 return;
 615         }
 616
 617         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 618                                 (!elems.mesh_id || !elems.mesh_config)) {
 619                 mpl_dbg("Mesh plink: missing necessary ie\n");
 620                 return;
 621         }
 622         /* Note the lines below are correct, the llid in the frame is the plid
 623          * from the point of view of this host.
 624          */
 625         memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
 626         if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
 627             (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
 628                 memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
 629
 630         rcu_read_lock();
 631
 632         sta = sta_info_get(sdata, mgmt->sa);
 633         if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
 634                 mpl_dbg("Mesh plink: cls or cnf from unknown peer\n");
 635                 rcu_read_unlock();
 636                 return;
 637         }
 638
 639         if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
 640             !rssi_threshold_check(sta, sdata)) {
 641                 mpl_dbg("Mesh plink: %pM does not meet rssi threshold\n",
 642                         mgmt->sa);
 643                 rcu_read_unlock();
 644                 return;
 645         }
 646
 647         if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
 648                 mpl_dbg("Mesh plink: Action frame from non-authed peer\n");
 649                 rcu_read_unlock();
 650                 return;
 651         }
 652
 653         if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
 654                 rcu_read_unlock();
 655                 return;
 656         }
 657
 658         /* Now we will figure out the appropriate event... */
 659         event = PLINK_UNDEFINED;
 660         if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 661             !mesh_matches_local(sdata, &elems)) {
 662                 matches_local = false;
 663                 switch (ftype) {
 664                 case WLAN_SP_MESH_PEERING_OPEN:
 665                         event = OPN_RJCT;
 666                         break;
 667                 case WLAN_SP_MESH_PEERING_CONFIRM:
 668                         event = CNF_RJCT;
 669                         break;
 670                 default:
 671                         break;
 672                 }
 673         }
 674
 675         if (!sta && !matches_local) {
 676                 rcu_read_unlock();
 677                 reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 678                 llid = 0;
 679                 mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 680                                     mgmt->sa, llid, plid, reason);
 681                 return;
 682         } else if (!sta) {
 683                 /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 684                 if (!mesh_plink_free_count(sdata)) {
 685                         mpl_dbg("Mesh plink error: no more free plinks\n");
 686                         rcu_read_unlock();
 687                         return;
 688                 }
 689                 event = OPN_ACPT;
 690         } else if (matches_local) {
 691                 switch (ftype) {
 692                 case WLAN_SP_MESH_PEERING_OPEN:
 693                         if (!mesh_plink_free_count(sdata) ||
 694                             (sta->plid && sta->plid != plid))
 695                                 event = OPN_IGNR;
 696                         else
 697                                 event = OPN_ACPT;
 698                         break;
 699                 case WLAN_SP_MESH_PEERING_CONFIRM:
 700                         if (!mesh_plink_free_count(sdata) ||
 701                             (sta->llid != llid || sta->plid != plid))
 702                                 event = CNF_IGNR;
 703                         else
 704                                 event = CNF_ACPT;
 705                         break;
 706                 case WLAN_SP_MESH_PEERING_CLOSE:
 707                         if (sta->plink_state == NL80211_PLINK_ESTAB)
 708                                 /* Do not check for llid or plid. This does not
 709                                  * follow the standard but since multiple plinks
 710                                  * per sta are not supported, it is necessary in
 711                                  * order to avoid a livelock when MP A sees an
 712                                  * establish peer link to MP B but MP B does not
 713                                  * see it. This can be caused by a timeout in
 714                                  * B's peer link establishment or B beign
 715                                  * restarted.
 716                                  */
 717                                 event = CLS_ACPT;
 718                         else if (sta->plid != plid)
 719                                 event = CLS_IGNR;
 720                         else if (ie_len == 7 && sta->llid != llid)
 721                                 event = CLS_IGNR;
 722                         else
 723                                 event = CLS_ACPT;
 724                         break;
 725                 default:
 726                         mpl_dbg("Mesh plink: unknown frame subtype\n");
 727                         rcu_read_unlock();
 728                         return;
 729                 }
 730         }
 731
 732         if (event == OPN_ACPT) {
 733                 /* allocate sta entry if necessary and update info */
 734                 sta = mesh_peer_init(sdata, mgmt->sa, &elems);
 735                 if (!sta) {
 736                         mpl_dbg("Mesh plink: failed to init peer!\n");
 737                         rcu_read_unlock();
 738                         return;
 739                 }
 740         }
 741
 742         mpl_dbg("Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
 743                 mgmt->sa, mplstates[sta->plink_state],
 744                 le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
 745                 event);
 746         reason = 0;
 747         spin_lock_bh(&sta->lock);
 748         switch (sta->plink_state) {
 749                 /* spin_unlock as soon as state is updated at each case */
 750         case NL80211_PLINK_LISTEN:
 751                 switch (event) {
 752                 case CLS_ACPT:
 753                         mesh_plink_fsm_restart(sta);
 754                         spin_unlock_bh(&sta->lock);
 755                         break;
 756                 case OPN_ACPT:
 757                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 758                         sta->plid = plid;
 759                         get_random_bytes(&llid, 2);
 760                         sta->llid = llid;
 761                         mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 762                         spin_unlock_bh(&sta->lock);
 763                         mesh_plink_frame_tx(sdata,
 764                                             WLAN_SP_MESH_PEERING_OPEN,
 765                                             sta->sta.addr, llid, 0, 0);
 766                         mesh_plink_frame_tx(sdata,
 767                                             WLAN_SP_MESH_PEERING_CONFIRM,
 768                                             sta->sta.addr, llid, plid, 0);
 769                         break;
 770                 default:
 771                         spin_unlock_bh(&sta->lock);
 772                         break;
 773                 }
 774                 break;
 775
 776         case NL80211_PLINK_OPN_SNT:
 777                 switch (event) {
 778                 case OPN_RJCT:
 779                 case CNF_RJCT:
 780                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 781                 case CLS_ACPT:
 782                         if (!reason)
 783                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 784                         sta->reason = reason;
 785                         sta->plink_state = NL80211_PLINK_HOLDING;
 786                         if (!mod_plink_timer(sta,
 787                                              dot11MeshHoldingTimeout(sdata)))
 788                                 sta->ignore_plink_timer = true;
 789
 790                         llid = sta->llid;
 791                         spin_unlock_bh(&sta->lock);
 792                         mesh_plink_frame_tx(sdata,
 793                                             WLAN_SP_MESH_PEERING_CLOSE,
 794                                             sta->sta.addr, llid, plid, reason);
 795                         break;
 796                 case OPN_ACPT:
 797                         /* retry timer is left untouched */
 798                         sta->plink_state = NL80211_PLINK_OPN_RCVD;
 799                         sta->plid = plid;
 800                         llid = sta->llid;
 801                         spin_unlock_bh(&sta->lock);
 802                         mesh_plink_frame_tx(sdata,
 803                                             WLAN_SP_MESH_PEERING_CONFIRM,
 804                                             sta->sta.addr, llid, plid, 0);
 805                         break;
 806                 case CNF_ACPT:
 807                         sta->plink_state = NL80211_PLINK_CNF_RCVD;
 808                         if (!mod_plink_timer(sta,
 809                                              dot11MeshConfirmTimeout(sdata)))
 810                                 sta->ignore_plink_timer = true;
 811
 812                         spin_unlock_bh(&sta->lock);
 813                         break;
 814                 default:
 815                         spin_unlock_bh(&sta->lock);
 816                         break;
 817                 }
 818                 break;
 819
 820         case NL80211_PLINK_OPN_RCVD:
 821                 switch (event) {
 822                 case OPN_RJCT:
 823                 case CNF_RJCT:
 824                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 825                 case CLS_ACPT:
 826                         if (!reason)
 827                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 828                         sta->reason = reason;
 829                         sta->plink_state = NL80211_PLINK_HOLDING;
 830                         if (!mod_plink_timer(sta,
 831                                              dot11MeshHoldingTimeout(sdata)))
 832                                 sta->ignore_plink_timer = true;
 833
 834                         llid = sta->llid;
 835                         spin_unlock_bh(&sta->lock);
 836                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 837                                             sta->sta.addr, llid, plid, reason);
 838                         break;
 839                 case OPN_ACPT:
 840                         llid = sta->llid;
 841                         spin_unlock_bh(&sta->lock);
 842                         mesh_plink_frame_tx(sdata,
 843                                             WLAN_SP_MESH_PEERING_CONFIRM,
 844                                             sta->sta.addr, llid, plid, 0);
 845                         break;
 846                 case CNF_ACPT:
 847                         del_timer(&sta->plink_timer);
 848                         sta->plink_state = NL80211_PLINK_ESTAB;
 849                         spin_unlock_bh(&sta->lock);
 850                         mesh_plink_inc_estab_count(sdata);
 851                         changed |= mesh_set_ht_prot_mode(sdata);
 852                         changed |= BSS_CHANGED_BEACON;
 853                         mpl_dbg("Mesh plink with %pM ESTABLISHED\n",
 854                                 sta->sta.addr);
 855                         break;
 856                 default:
 857                         spin_unlock_bh(&sta->lock);
 858                         break;
 859                 }
 860                 break;
 861
 862         case NL80211_PLINK_CNF_RCVD:
 863                 switch (event) {
 864                 case OPN_RJCT:
 865                 case CNF_RJCT:
 866                         reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 867                 case CLS_ACPT:
 868                         if (!reason)
 869                                 reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 870                         sta->reason = reason;
 871                         sta->plink_state = NL80211_PLINK_HOLDING;
 872                         if (!mod_plink_timer(sta,
 873                                              dot11MeshHoldingTimeout(sdata)))
 874                                 sta->ignore_plink_timer = true;
 875
 876                         llid = sta->llid;
 877                         spin_unlock_bh(&sta->lock);
 878                         mesh_plink_frame_tx(sdata,
 879                                             WLAN_SP_MESH_PEERING_CLOSE,
 880                                             sta->sta.addr, llid, plid, reason);
 881                         break;
 882                 case OPN_ACPT:
 883                         del_timer(&sta->plink_timer);
 884                         sta->plink_state = NL80211_PLINK_ESTAB;
 885                         spin_unlock_bh(&sta->lock);
 886                         mesh_plink_inc_estab_count(sdata);
 887                         changed |= mesh_set_ht_prot_mode(sdata);
 888                         changed |= BSS_CHANGED_BEACON;
 889                         mpl_dbg("Mesh plink with %pM ESTABLISHED\n",
 890                                 sta->sta.addr);
 891                         mesh_plink_frame_tx(sdata,
 892                                             WLAN_SP_MESH_PEERING_CONFIRM,
 893                                             sta->sta.addr, llid, plid, 0);
 894                         break;
 895                 default:
 896                         spin_unlock_bh(&sta->lock);
 897                         break;
 898                 }
 899                 break;
 900
 901         case NL80211_PLINK_ESTAB:
 902                 switch (event) {
 903                 case CLS_ACPT:
 904                         reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 905                         sta->reason = reason;
 906                         __mesh_plink_deactivate(sta);
 907                         sta->plink_state = NL80211_PLINK_HOLDING;
 908                         llid = sta->llid;
 909                         mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 910                         spin_unlock_bh(&sta->lock);
 911                         changed |= mesh_set_ht_prot_mode(sdata);
 912                         changed |= BSS_CHANGED_BEACON;
 913                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 914                                             sta->sta.addr, llid, plid, reason);
 915                         break;
 916                 case OPN_ACPT:
 917                         llid = sta->llid;
 918                         spin_unlock_bh(&sta->lock);
 919                         mesh_plink_frame_tx(sdata,
 920                                             WLAN_SP_MESH_PEERING_CONFIRM,
 921                                             sta->sta.addr, llid, plid, 0);
 922                         break;
 923                 default:
 924                         spin_unlock_bh(&sta->lock);
 925                         break;
 926                 }
 927                 break;
 928         case NL80211_PLINK_HOLDING:
 929                 switch (event) {
 930                 case CLS_ACPT:
 931                         if (del_timer(&sta->plink_timer))
 932                                 sta->ignore_plink_timer = 1;
 933                         mesh_plink_fsm_restart(sta);
 934                         spin_unlock_bh(&sta->lock);
 935                         break;
 936                 case OPN_ACPT:
 937                 case CNF_ACPT:
 938                 case OPN_RJCT:
 939                 case CNF_RJCT:
 940                         llid = sta->llid;
 941                         reason = sta->reason;
 942                         spin_unlock_bh(&sta->lock);
 943                         mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 944                                             sta->sta.addr, llid, plid, reason);
 945                         break;
 946                 default:
 947                         spin_unlock_bh(&sta->lock);
 948                 }
 949                 break;
 950         default:
 951                 /* should not get here, PLINK_BLOCKED is dealt with at the
 952                  * beginning of the function
 953                  */
 954                 spin_unlock_bh(&sta->lock);
 955                 break;
 956         }
 957
 958         rcu_read_unlock();
 959
 960         if (changed)
 961                 ieee80211_bss_info_change_notify(sdata, changed);
 962 }