linux/net/mac80211/mesh_plink.c
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   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#define dot11MeshMaxRetries(s) (s->u.mesh.mshcfg.dot11MeshMaxRetries)
  23#define dot11MeshRetryTimeout(s) (s->u.mesh.mshcfg.dot11MeshRetryTimeout)
  24#define dot11MeshConfirmTimeout(s) (s->u.mesh.mshcfg.dot11MeshConfirmTimeout)
  25#define dot11MeshHoldingTimeout(s) (s->u.mesh.mshcfg.dot11MeshHoldingTimeout)
  26#define dot11MeshMaxPeerLinks(s) (s->u.mesh.mshcfg.dot11MeshMaxPeerLinks)
  27
  28/* We only need a valid sta if user configured a minimum rssi_threshold. */
  29#define rssi_threshold_check(sta, sdata) \
  30                (sdata->u.mesh.mshcfg.rssi_threshold == 0 ||\
  31                (sta && (s8) -ewma_read(&sta->avg_signal) > \
  32                sdata->u.mesh.mshcfg.rssi_threshold))
  33
  34enum plink_event {
  35        PLINK_UNDEFINED,
  36        OPN_ACPT,
  37        OPN_RJCT,
  38        OPN_IGNR,
  39        CNF_ACPT,
  40        CNF_RJCT,
  41        CNF_IGNR,
  42        CLS_ACPT,
  43        CLS_IGNR
  44};
  45
  46static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
  47                enum ieee80211_self_protected_actioncode action,
  48                u8 *da, __le16 llid, __le16 plid, __le16 reason);
  49
  50static inline
  51void mesh_plink_inc_estab_count(struct ieee80211_sub_if_data *sdata)
  52{
  53        atomic_inc(&sdata->u.mesh.mshstats.estab_plinks);
  54        mesh_accept_plinks_update(sdata);
  55}
  56
  57static inline
  58void mesh_plink_dec_estab_count(struct ieee80211_sub_if_data *sdata)
  59{
  60        atomic_dec(&sdata->u.mesh.mshstats.estab_plinks);
  61        mesh_accept_plinks_update(sdata);
  62}
  63
  64/**
  65 * mesh_plink_fsm_restart - restart a mesh peer link finite state machine
  66 *
  67 * @sta: mesh peer link to restart
  68 *
  69 * Locking: this function must be called holding sta->lock
  70 */
  71static inline void mesh_plink_fsm_restart(struct sta_info *sta)
  72{
  73        sta->plink_state = NL80211_PLINK_LISTEN;
  74        sta->llid = sta->plid = sta->reason = 0;
  75        sta->plink_retries = 0;
  76}
  77
  78/*
  79 * Allocate mesh sta entry and insert into station table
  80 */
  81static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
  82                                         u8 *hw_addr)
  83{
  84        struct sta_info *sta;
  85
  86        if (sdata->local->num_sta >= MESH_MAX_PLINKS)
  87                return NULL;
  88
  89        sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
  90        if (!sta)
  91                return NULL;
  92
  93        sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
  94        sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
  95        sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
  96
  97        set_sta_flag(sta, WLAN_STA_WME);
  98
  99        return sta;
 100}
 101
 102/**
 103 * mesh_set_ht_prot_mode - set correct HT protection mode
 104 *
 105 * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 106 * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 107 * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 108 * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 109 * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 110 * HT20 peer is present. Otherwise no-protection mode is selected.
 111 */
 112static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 113{
 114        struct ieee80211_local *local = sdata->local;
 115        struct sta_info *sta;
 116        u32 changed = 0;
 117        u16 ht_opmode;
 118        bool non_ht_sta = false, ht20_sta = false;
 119
 120        if (local->_oper_channel_type == NL80211_CHAN_NO_HT)
 121                return 0;
 122
 123        rcu_read_lock();
 124        list_for_each_entry_rcu(sta, &local->sta_list, list) {
 125                if (sdata != sta->sdata ||
 126                    sta->plink_state != NL80211_PLINK_ESTAB)
 127                        continue;
 128
 129                switch (sta->ch_type) {
 130                case NL80211_CHAN_NO_HT:
 131                        mpl_dbg(sdata,
 132                                "mesh_plink %pM: nonHT sta (%pM) is present\n",
 133                                sdata->vif.addr, sta->sta.addr);
 134                        non_ht_sta = true;
 135                        goto out;
 136                case NL80211_CHAN_HT20:
 137                        mpl_dbg(sdata,
 138                                "mesh_plink %pM: HT20 sta (%pM) is present\n",
 139                                sdata->vif.addr, sta->sta.addr);
 140                        ht20_sta = true;
 141                default:
 142                        break;
 143                }
 144        }
 145out:
 146        rcu_read_unlock();
 147
 148        if (non_ht_sta)
 149                ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 150        else if (ht20_sta && local->_oper_channel_type > NL80211_CHAN_HT20)
 151                ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 152        else
 153                ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 154
 155        if (sdata->vif.bss_conf.ht_operation_mode != ht_opmode) {
 156                sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 157                sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 158                changed = BSS_CHANGED_HT;
 159                mpl_dbg(sdata,
 160                        "mesh_plink %pM: protection mode changed to %d\n",
 161                        sdata->vif.addr, ht_opmode);
 162        }
 163
 164        return changed;
 165}
 166
 167/**
 168 * __mesh_plink_deactivate - deactivate mesh peer link
 169 *
 170 * @sta: mesh peer link to deactivate
 171 *
 172 * All mesh paths with this peer as next hop will be flushed
 173 *
 174 * Locking: the caller must hold sta->lock
 175 */
 176static bool __mesh_plink_deactivate(struct sta_info *sta)
 177{
 178        struct ieee80211_sub_if_data *sdata = sta->sdata;
 179        bool deactivated = false;
 180
 181        if (sta->plink_state == NL80211_PLINK_ESTAB) {
 182                mesh_plink_dec_estab_count(sdata);
 183                deactivated = true;
 184        }
 185        sta->plink_state = NL80211_PLINK_BLOCKED;
 186        mesh_path_flush_by_nexthop(sta);
 187
 188        return deactivated;
 189}
 190
 191/**
 192 * mesh_plink_deactivate - deactivate mesh peer link
 193 *
 194 * @sta: mesh peer link to deactivate
 195 *
 196 * All mesh paths with this peer as next hop will be flushed
 197 */
 198void mesh_plink_deactivate(struct sta_info *sta)
 199{
 200        struct ieee80211_sub_if_data *sdata = sta->sdata;
 201        bool deactivated;
 202
 203        spin_lock_bh(&sta->lock);
 204        deactivated = __mesh_plink_deactivate(sta);
 205        sta->reason = cpu_to_le16(WLAN_REASON_MESH_PEER_CANCELED);
 206        mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 207                            sta->sta.addr, sta->llid, sta->plid,
 208                            sta->reason);
 209        spin_unlock_bh(&sta->lock);
 210
 211        if (deactivated)
 212                ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 213}
 214
 215static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 216                enum ieee80211_self_protected_actioncode action,
 217                u8 *da, __le16 llid, __le16 plid, __le16 reason) {
 218        struct ieee80211_local *local = sdata->local;
 219        struct sk_buff *skb;
 220        struct ieee80211_mgmt *mgmt;
 221        bool include_plid = false;
 222        u16 peering_proto = 0;
 223        u8 *pos, ie_len = 4;
 224        int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.self_prot) +
 225                      sizeof(mgmt->u.action.u.self_prot);
 226
 227        skb = dev_alloc_skb(local->tx_headroom +
 228                            hdr_len +
 229                            2 + /* capability info */
 230                            2 + /* AID */
 231                            2 + 8 + /* supported rates */
 232                            2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 233                            2 + sdata->u.mesh.mesh_id_len +
 234                            2 + sizeof(struct ieee80211_meshconf_ie) +
 235                            2 + sizeof(struct ieee80211_ht_cap) +
 236                            2 + sizeof(struct ieee80211_ht_operation) +
 237                            2 + 8 + /* peering IE */
 238                            sdata->u.mesh.ie_len);
 239        if (!skb)
 240                return -1;
 241        skb_reserve(skb, local->tx_headroom);
 242        mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 243        memset(mgmt, 0, hdr_len);
 244        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 245                                          IEEE80211_STYPE_ACTION);
 246        memcpy(mgmt->da, da, ETH_ALEN);
 247        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 248        memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 249        mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 250        mgmt->u.action.u.self_prot.action_code = action;
 251
 252        if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 253                /* capability info */
 254                pos = skb_put(skb, 2);
 255                memset(pos, 0, 2);
 256                if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 257                        /* AID */
 258                        pos = skb_put(skb, 2);
 259                        memcpy(pos + 2, &plid, 2);
 260                }
 261                if (ieee80211_add_srates_ie(sdata, skb, true) ||
 262                    ieee80211_add_ext_srates_ie(sdata, skb, true) ||
 263                    mesh_add_rsn_ie(skb, sdata) ||
 264                    mesh_add_meshid_ie(skb, sdata) ||
 265                    mesh_add_meshconf_ie(skb, sdata))
 266                        return -1;
 267        } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 268                if (mesh_add_meshid_ie(skb, sdata))
 269                        return -1;
 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                return -EINVAL;
 289        }
 290
 291        if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 292                return -ENOMEM;
 293
 294        pos = skb_put(skb, 2 + ie_len);
 295        *pos++ = WLAN_EID_PEER_MGMT;
 296        *pos++ = ie_len;
 297        memcpy(pos, &peering_proto, 2);
 298        pos += 2;
 299        memcpy(pos, &llid, 2);
 300        pos += 2;
 301        if (include_plid) {
 302                memcpy(pos, &plid, 2);
 303                pos += 2;
 304        }
 305        if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 306                memcpy(pos, &reason, 2);
 307                pos += 2;
 308        }
 309
 310        if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 311                if (mesh_add_ht_cap_ie(skb, sdata) ||
 312                    mesh_add_ht_oper_ie(skb, sdata))
 313                        return -1;
 314        }
 315
 316        if (mesh_add_vendor_ies(skb, sdata))
 317                return -1;
 318
 319        ieee80211_tx_skb(sdata, skb);
 320        return 0;
 321}
 322
 323/**
 324 * mesh_peer_init - initialize new mesh peer and return resulting sta_info
 325 *
 326 * @sdata: local meshif
 327 * @addr: peer's address
 328 * @elems: IEs from beacon or mesh peering frame
 329 *
 330 * call under RCU
 331 */
 332static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata,
 333                                       u8 *addr,
 334                                       struct ieee802_11_elems *elems)
 335{
 336        struct ieee80211_local *local = sdata->local;
 337        enum ieee80211_band band = local->oper_channel->band;
 338        struct ieee80211_supported_band *sband;
 339        u32 rates, basic_rates = 0;
 340        struct sta_info *sta;
 341        bool insert = false;
 342
 343        sband = local->hw.wiphy->bands[band];
 344        rates = ieee80211_sta_get_rates(local, elems, band, &basic_rates);
 345
 346        sta = sta_info_get(sdata, addr);
 347        if (!sta) {
 348                /* Userspace handles peer allocation when security is enabled */
 349                if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
 350                        cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 351                                                           elems->ie_start,
 352                                                           elems->total_len,
 353                                                           GFP_ATOMIC);
 354                        return NULL;
 355                }
 356
 357                sta = mesh_plink_alloc(sdata, addr);
 358                if (!sta)
 359                        return NULL;
 360                insert = true;
 361        }
 362
 363        spin_lock_bh(&sta->lock);
 364        sta->last_rx = jiffies;
 365        sta->sta.supp_rates[band] = rates;
 366        if (elems->ht_cap_elem &&
 367            sdata->local->_oper_channel_type != NL80211_CHAN_NO_HT)
 368                ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 369                                                  elems->ht_cap_elem,
 370                                                  &sta->sta.ht_cap);
 371        else
 372                memset(&sta->sta.ht_cap, 0, sizeof(sta->sta.ht_cap));
 373
 374        if (elems->ht_operation) {
 375                if (!(elems->ht_operation->ht_param &
 376                      IEEE80211_HT_PARAM_CHAN_WIDTH_ANY))
 377                        sta->sta.ht_cap.cap &=
 378                                            ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
 379                sta->ch_type =
 380                        ieee80211_ht_oper_to_channel_type(elems->ht_operation);
 381        }
 382
 383        rate_control_rate_init(sta);
 384        spin_unlock_bh(&sta->lock);
 385
 386        if (insert && sta_info_insert(sta))
 387                return NULL;
 388
 389        return sta;
 390}
 391
 392void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 393                           u8 *hw_addr,
 394                           struct ieee802_11_elems *elems)
 395{
 396        struct sta_info *sta;
 397
 398        rcu_read_lock();
 399        sta = mesh_peer_init(sdata, hw_addr, elems);
 400        if (!sta)
 401                goto out;
 402
 403        if (mesh_peer_accepts_plinks(elems) &&
 404            sta->plink_state == NL80211_PLINK_LISTEN &&
 405            sdata->u.mesh.accepting_plinks &&
 406            sdata->u.mesh.mshcfg.auto_open_plinks &&
 407            rssi_threshold_check(sta, sdata))
 408                mesh_plink_open(sta);
 409
 410out:
 411        rcu_read_unlock();
 412}
 413
 414static void mesh_plink_timer(unsigned long data)
 415{
 416        struct sta_info *sta;
 417        __le16 llid, plid, reason;
 418        struct ieee80211_sub_if_data *sdata;
 419
 420        /*
 421         * This STA is valid because sta_info_destroy() will
 422         * del_timer_sync() this timer after having made sure
 423         * it cannot be readded (by deleting the plink.)
 424         */
 425        sta = (struct sta_info *) data;
 426
 427        if (sta->sdata->local->quiescing) {
 428                sta->plink_timer_was_running = true;
 429                return;
 430        }
 431
 432        spin_lock_bh(&sta->lock);
 433        if (sta->ignore_plink_timer) {
 434                sta->ignore_plink_timer = false;
 435                spin_unlock_bh(&sta->lock);
 436                return;
 437        }
 438        mpl_dbg(sta->sdata,
 439                "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(sta->sdata,
 453                                "Mesh plink for %pM (retry, timeout): %d %d\n",
 454                                sta->sta.addr, sta->plink_retries,
 455                                sta->plink_timeout);
 456                        get_random_bytes(&rand, sizeof(u32));
 457                        sta->plink_timeout = sta->plink_timeout +
 458                                             rand % sta->plink_timeout;
 459                        ++sta->plink_retries;
 460                        mod_plink_timer(sta, sta->plink_timeout);
 461                        spin_unlock_bh(&sta->lock);
 462                        mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 463                                            sta->sta.addr, llid, 0, 0);
 464                        break;
 465                }
 466                reason = cpu_to_le16(WLAN_REASON_MESH_MAX_RETRIES);
 467                /* fall through on else */
 468        case NL80211_PLINK_CNF_RCVD:
 469                /* confirm timer */
 470                if (!reason)
 471                        reason = cpu_to_le16(WLAN_REASON_MESH_CONFIRM_TIMEOUT);
 472                sta->plink_state = NL80211_PLINK_HOLDING;
 473                mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 474                spin_unlock_bh(&sta->lock);
 475                mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 476                                    sta->sta.addr, llid, plid, reason);
 477                break;
 478        case NL80211_PLINK_HOLDING:
 479                /* holding timer */
 480                del_timer(&sta->plink_timer);
 481                mesh_plink_fsm_restart(sta);
 482                spin_unlock_bh(&sta->lock);
 483                break;
 484        default:
 485                spin_unlock_bh(&sta->lock);
 486                break;
 487        }
 488}
 489
 490#ifdef CONFIG_PM
 491void mesh_plink_quiesce(struct sta_info *sta)
 492{
 493        if (del_timer_sync(&sta->plink_timer))
 494                sta->plink_timer_was_running = true;
 495}
 496
 497void mesh_plink_restart(struct sta_info *sta)
 498{
 499        if (sta->plink_timer_was_running) {
 500                add_timer(&sta->plink_timer);
 501                sta->plink_timer_was_running = false;
 502        }
 503}
 504#endif
 505
 506static inline void mesh_plink_timer_set(struct sta_info *sta, int timeout)
 507{
 508        sta->plink_timer.expires = jiffies + (HZ * timeout / 1000);
 509        sta->plink_timer.data = (unsigned long) sta;
 510        sta->plink_timer.function = mesh_plink_timer;
 511        sta->plink_timeout = timeout;
 512        add_timer(&sta->plink_timer);
 513}
 514
 515int mesh_plink_open(struct sta_info *sta)
 516{
 517        __le16 llid;
 518        struct ieee80211_sub_if_data *sdata = sta->sdata;
 519
 520        if (!test_sta_flag(sta, WLAN_STA_AUTH))
 521                return -EPERM;
 522
 523        spin_lock_bh(&sta->lock);
 524        get_random_bytes(&llid, 2);
 525        sta->llid = llid;
 526        if (sta->plink_state != NL80211_PLINK_LISTEN) {
 527                spin_unlock_bh(&sta->lock);
 528                return -EBUSY;
 529        }
 530        sta->plink_state = NL80211_PLINK_OPN_SNT;
 531        mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 532        spin_unlock_bh(&sta->lock);
 533        mpl_dbg(sdata,
 534                "Mesh plink: starting establishment with %pM\n",
 535                sta->sta.addr);
 536
 537        return mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_OPEN,
 538                                   sta->sta.addr, llid, 0, 0);
 539}
 540
 541void mesh_plink_block(struct sta_info *sta)
 542{
 543        struct ieee80211_sub_if_data *sdata = sta->sdata;
 544        bool deactivated;
 545
 546        spin_lock_bh(&sta->lock);
 547        deactivated = __mesh_plink_deactivate(sta);
 548        sta->plink_state = NL80211_PLINK_BLOCKED;
 549        spin_unlock_bh(&sta->lock);
 550
 551        if (deactivated)
 552                ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
 553}
 554
 555
 556void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_mgmt *mgmt,
 557                         size_t len, struct ieee80211_rx_status *rx_status)
 558{
 559        struct ieee802_11_elems elems;
 560        struct sta_info *sta;
 561        enum plink_event event;
 562        enum ieee80211_self_protected_actioncode ftype;
 563        size_t baselen;
 564        bool matches_local = true;
 565        u8 ie_len;
 566        u8 *baseaddr;
 567        u32 changed = 0;
 568        __le16 plid, llid, reason;
 569        static const char *mplstates[] = {
 570                [NL80211_PLINK_LISTEN] = "LISTEN",
 571                [NL80211_PLINK_OPN_SNT] = "OPN-SNT",
 572                [NL80211_PLINK_OPN_RCVD] = "OPN-RCVD",
 573                [NL80211_PLINK_CNF_RCVD] = "CNF_RCVD",
 574                [NL80211_PLINK_ESTAB] = "ESTAB",
 575                [NL80211_PLINK_HOLDING] = "HOLDING",
 576                [NL80211_PLINK_BLOCKED] = "BLOCKED"
 577        };
 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(sdata,
 585                        "Mesh plink: ignore frame from multicast address\n");
 586                return;
 587        }
 588
 589        baseaddr = mgmt->u.action.u.self_prot.variable;
 590        baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
 591        if (mgmt->u.action.u.self_prot.action_code ==
 592                                                WLAN_SP_MESH_PEERING_CONFIRM) {
 593                baseaddr += 4;
 594                baselen += 4;
 595        }
 596        ieee802_11_parse_elems(baseaddr, len - baselen, &elems);
 597        if (!elems.peering) {
 598                mpl_dbg(sdata,
 599                        "Mesh plink: missing necessary peer link ie\n");
 600                return;
 601        }
 602        if (elems.rsn_len &&
 603                        sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
 604                mpl_dbg(sdata,
 605                        "Mesh plink: can't establish link with secure peer\n");
 606                return;
 607        }
 608
 609        ftype = mgmt->u.action.u.self_prot.action_code;
 610        ie_len = elems.peering_len;
 611        if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
 612            (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
 613            (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
 614                                                        && ie_len != 8)) {
 615                mpl_dbg(sdata,
 616                        "Mesh plink: incorrect plink ie length %d %d\n",
 617                        ftype, ie_len);
 618                return;
 619        }
 620
 621        if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 622                                (!elems.mesh_id || !elems.mesh_config)) {
 623                mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
 624                return;
 625        }
 626        /* Note the lines below are correct, the llid in the frame is the plid
 627         * from the point of view of this host.
 628         */
 629        memcpy(&plid, PLINK_GET_LLID(elems.peering), 2);
 630        if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
 631            (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
 632                memcpy(&llid, PLINK_GET_PLID(elems.peering), 2);
 633
 634        rcu_read_lock();
 635
 636        sta = sta_info_get(sdata, mgmt->sa);
 637        if (!sta && ftype != WLAN_SP_MESH_PEERING_OPEN) {
 638                mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
 639                rcu_read_unlock();
 640                return;
 641        }
 642
 643        if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
 644            !rssi_threshold_check(sta, sdata)) {
 645                mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
 646                        mgmt->sa);
 647                rcu_read_unlock();
 648                return;
 649        }
 650
 651        if (sta && !test_sta_flag(sta, WLAN_STA_AUTH)) {
 652                mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
 653                rcu_read_unlock();
 654                return;
 655        }
 656
 657        if (sta && sta->plink_state == NL80211_PLINK_BLOCKED) {
 658                rcu_read_unlock();
 659                return;
 660        }
 661
 662        /* Now we will figure out the appropriate event... */
 663        event = PLINK_UNDEFINED;
 664        if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
 665            !mesh_matches_local(sdata, &elems)) {
 666                matches_local = false;
 667                switch (ftype) {
 668                case WLAN_SP_MESH_PEERING_OPEN:
 669                        event = OPN_RJCT;
 670                        break;
 671                case WLAN_SP_MESH_PEERING_CONFIRM:
 672                        event = CNF_RJCT;
 673                        break;
 674                default:
 675                        break;
 676                }
 677        }
 678
 679        if (!sta && !matches_local) {
 680                rcu_read_unlock();
 681                reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 682                llid = 0;
 683                mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 684                                    mgmt->sa, llid, plid, reason);
 685                return;
 686        } else if (!sta) {
 687                /* ftype == WLAN_SP_MESH_PEERING_OPEN */
 688                if (!mesh_plink_free_count(sdata)) {
 689                        mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
 690                        rcu_read_unlock();
 691                        return;
 692                }
 693                event = OPN_ACPT;
 694        } else if (matches_local) {
 695                switch (ftype) {
 696                case WLAN_SP_MESH_PEERING_OPEN:
 697                        if (!mesh_plink_free_count(sdata) ||
 698                            (sta->plid && sta->plid != plid))
 699                                event = OPN_IGNR;
 700                        else
 701                                event = OPN_ACPT;
 702                        break;
 703                case WLAN_SP_MESH_PEERING_CONFIRM:
 704                        if (!mesh_plink_free_count(sdata) ||
 705                            (sta->llid != llid || sta->plid != plid))
 706                                event = CNF_IGNR;
 707                        else
 708                                event = CNF_ACPT;
 709                        break;
 710                case WLAN_SP_MESH_PEERING_CLOSE:
 711                        if (sta->plink_state == NL80211_PLINK_ESTAB)
 712                                /* Do not check for llid or plid. This does not
 713                                 * follow the standard but since multiple plinks
 714                                 * per sta are not supported, it is necessary in
 715                                 * order to avoid a livelock when MP A sees an
 716                                 * establish peer link to MP B but MP B does not
 717                                 * see it. This can be caused by a timeout in
 718                                 * B's peer link establishment or B beign
 719                                 * restarted.
 720                                 */
 721                                event = CLS_ACPT;
 722                        else if (sta->plid != plid)
 723                                event = CLS_IGNR;
 724                        else if (ie_len == 7 && sta->llid != llid)
 725                                event = CLS_IGNR;
 726                        else
 727                                event = CLS_ACPT;
 728                        break;
 729                default:
 730                        mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
 731                        rcu_read_unlock();
 732                        return;
 733                }
 734        }
 735
 736        if (event == OPN_ACPT) {
 737                /* allocate sta entry if necessary and update info */
 738                sta = mesh_peer_init(sdata, mgmt->sa, &elems);
 739                if (!sta) {
 740                        mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
 741                        rcu_read_unlock();
 742                        return;
 743                }
 744        }
 745
 746        mpl_dbg(sdata,
 747                "Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
 748                mgmt->sa, mplstates[sta->plink_state],
 749                le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
 750                event);
 751        reason = 0;
 752        spin_lock_bh(&sta->lock);
 753        switch (sta->plink_state) {
 754                /* spin_unlock as soon as state is updated at each case */
 755        case NL80211_PLINK_LISTEN:
 756                switch (event) {
 757                case CLS_ACPT:
 758                        mesh_plink_fsm_restart(sta);
 759                        spin_unlock_bh(&sta->lock);
 760                        break;
 761                case OPN_ACPT:
 762                        sta->plink_state = NL80211_PLINK_OPN_RCVD;
 763                        sta->plid = plid;
 764                        get_random_bytes(&llid, 2);
 765                        sta->llid = llid;
 766                        mesh_plink_timer_set(sta, dot11MeshRetryTimeout(sdata));
 767                        spin_unlock_bh(&sta->lock);
 768                        mesh_plink_frame_tx(sdata,
 769                                            WLAN_SP_MESH_PEERING_OPEN,
 770                                            sta->sta.addr, llid, 0, 0);
 771                        mesh_plink_frame_tx(sdata,
 772                                            WLAN_SP_MESH_PEERING_CONFIRM,
 773                                            sta->sta.addr, llid, plid, 0);
 774                        break;
 775                default:
 776                        spin_unlock_bh(&sta->lock);
 777                        break;
 778                }
 779                break;
 780
 781        case NL80211_PLINK_OPN_SNT:
 782                switch (event) {
 783                case OPN_RJCT:
 784                case CNF_RJCT:
 785                        reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 786                case CLS_ACPT:
 787                        if (!reason)
 788                                reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 789                        sta->reason = reason;
 790                        sta->plink_state = NL80211_PLINK_HOLDING;
 791                        if (!mod_plink_timer(sta,
 792                                             dot11MeshHoldingTimeout(sdata)))
 793                                sta->ignore_plink_timer = true;
 794
 795                        llid = sta->llid;
 796                        spin_unlock_bh(&sta->lock);
 797                        mesh_plink_frame_tx(sdata,
 798                                            WLAN_SP_MESH_PEERING_CLOSE,
 799                                            sta->sta.addr, llid, plid, reason);
 800                        break;
 801                case OPN_ACPT:
 802                        /* retry timer is left untouched */
 803                        sta->plink_state = NL80211_PLINK_OPN_RCVD;
 804                        sta->plid = plid;
 805                        llid = sta->llid;
 806                        spin_unlock_bh(&sta->lock);
 807                        mesh_plink_frame_tx(sdata,
 808                                            WLAN_SP_MESH_PEERING_CONFIRM,
 809                                            sta->sta.addr, llid, plid, 0);
 810                        break;
 811                case CNF_ACPT:
 812                        sta->plink_state = NL80211_PLINK_CNF_RCVD;
 813                        if (!mod_plink_timer(sta,
 814                                             dot11MeshConfirmTimeout(sdata)))
 815                                sta->ignore_plink_timer = true;
 816
 817                        spin_unlock_bh(&sta->lock);
 818                        break;
 819                default:
 820                        spin_unlock_bh(&sta->lock);
 821                        break;
 822                }
 823                break;
 824
 825        case NL80211_PLINK_OPN_RCVD:
 826                switch (event) {
 827                case OPN_RJCT:
 828                case CNF_RJCT:
 829                        reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 830                case CLS_ACPT:
 831                        if (!reason)
 832                                reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 833                        sta->reason = reason;
 834                        sta->plink_state = NL80211_PLINK_HOLDING;
 835                        if (!mod_plink_timer(sta,
 836                                             dot11MeshHoldingTimeout(sdata)))
 837                                sta->ignore_plink_timer = true;
 838
 839                        llid = sta->llid;
 840                        spin_unlock_bh(&sta->lock);
 841                        mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 842                                            sta->sta.addr, llid, plid, reason);
 843                        break;
 844                case OPN_ACPT:
 845                        llid = sta->llid;
 846                        spin_unlock_bh(&sta->lock);
 847                        mesh_plink_frame_tx(sdata,
 848                                            WLAN_SP_MESH_PEERING_CONFIRM,
 849                                            sta->sta.addr, llid, plid, 0);
 850                        break;
 851                case CNF_ACPT:
 852                        del_timer(&sta->plink_timer);
 853                        sta->plink_state = NL80211_PLINK_ESTAB;
 854                        spin_unlock_bh(&sta->lock);
 855                        mesh_plink_inc_estab_count(sdata);
 856                        changed |= mesh_set_ht_prot_mode(sdata);
 857                        changed |= BSS_CHANGED_BEACON;
 858                        mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 859                                sta->sta.addr);
 860                        break;
 861                default:
 862                        spin_unlock_bh(&sta->lock);
 863                        break;
 864                }
 865                break;
 866
 867        case NL80211_PLINK_CNF_RCVD:
 868                switch (event) {
 869                case OPN_RJCT:
 870                case CNF_RJCT:
 871                        reason = cpu_to_le16(WLAN_REASON_MESH_CONFIG);
 872                case CLS_ACPT:
 873                        if (!reason)
 874                                reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 875                        sta->reason = reason;
 876                        sta->plink_state = NL80211_PLINK_HOLDING;
 877                        if (!mod_plink_timer(sta,
 878                                             dot11MeshHoldingTimeout(sdata)))
 879                                sta->ignore_plink_timer = true;
 880
 881                        llid = sta->llid;
 882                        spin_unlock_bh(&sta->lock);
 883                        mesh_plink_frame_tx(sdata,
 884                                            WLAN_SP_MESH_PEERING_CLOSE,
 885                                            sta->sta.addr, llid, plid, reason);
 886                        break;
 887                case OPN_ACPT:
 888                        del_timer(&sta->plink_timer);
 889                        sta->plink_state = NL80211_PLINK_ESTAB;
 890                        spin_unlock_bh(&sta->lock);
 891                        mesh_plink_inc_estab_count(sdata);
 892                        changed |= mesh_set_ht_prot_mode(sdata);
 893                        changed |= BSS_CHANGED_BEACON;
 894                        mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n",
 895                                sta->sta.addr);
 896                        mesh_plink_frame_tx(sdata,
 897                                            WLAN_SP_MESH_PEERING_CONFIRM,
 898                                            sta->sta.addr, llid, plid, 0);
 899                        break;
 900                default:
 901                        spin_unlock_bh(&sta->lock);
 902                        break;
 903                }
 904                break;
 905
 906        case NL80211_PLINK_ESTAB:
 907                switch (event) {
 908                case CLS_ACPT:
 909                        reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
 910                        sta->reason = reason;
 911                        __mesh_plink_deactivate(sta);
 912                        sta->plink_state = NL80211_PLINK_HOLDING;
 913                        llid = sta->llid;
 914                        mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
 915                        spin_unlock_bh(&sta->lock);
 916                        changed |= mesh_set_ht_prot_mode(sdata);
 917                        changed |= BSS_CHANGED_BEACON;
 918                        mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 919                                            sta->sta.addr, llid, plid, reason);
 920                        break;
 921                case OPN_ACPT:
 922                        llid = sta->llid;
 923                        spin_unlock_bh(&sta->lock);
 924                        mesh_plink_frame_tx(sdata,
 925                                            WLAN_SP_MESH_PEERING_CONFIRM,
 926                                            sta->sta.addr, llid, plid, 0);
 927                        break;
 928                default:
 929                        spin_unlock_bh(&sta->lock);
 930                        break;
 931                }
 932                break;
 933        case NL80211_PLINK_HOLDING:
 934                switch (event) {
 935                case CLS_ACPT:
 936                        if (del_timer(&sta->plink_timer))
 937                                sta->ignore_plink_timer = 1;
 938                        mesh_plink_fsm_restart(sta);
 939                        spin_unlock_bh(&sta->lock);
 940                        break;
 941                case OPN_ACPT:
 942                case CNF_ACPT:
 943                case OPN_RJCT:
 944                case CNF_RJCT:
 945                        llid = sta->llid;
 946                        reason = sta->reason;
 947                        spin_unlock_bh(&sta->lock);
 948                        mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
 949                                            sta->sta.addr, llid, plid, reason);
 950                        break;
 951                default:
 952                        spin_unlock_bh(&sta->lock);
 953                }
 954                break;
 955        default:
 956                /* should not get here, PLINK_BLOCKED is dealt with at the
 957                 * beginning of the function
 958                 */
 959                spin_unlock_bh(&sta->lock);
 960                break;
 961        }
 962
 963        rcu_read_unlock();
 964
 965        if (changed)
 966                ieee80211_bss_info_change_notify(sdata, changed);
 967}
 968
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