linux/net/mac80211/mesh_plink.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (c) 2008, 2009 open80211s Ltd.
   4 * Copyright (C) 2019 Intel Corporation
   5 * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   6 */
   7#include <linux/gfp.h>
   8#include <linux/kernel.h>
   9#include <linux/random.h>
  10#include <linux/rculist.h>
  11
  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
  23enum 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
  35static 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
  45static 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. */
  58static 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 */
  75static 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 */
  93static u32 mesh_set_short_slot_time(struct ieee80211_sub_if_data *sdata)
  94{
  95        struct ieee80211_local *local = sdata->local;
  96        struct ieee80211_supported_band *sband;
  97        struct sta_info *sta;
  98        u32 erp_rates = 0, changed = 0;
  99        int i;
 100        bool short_slot = false;
 101
 102        sband = ieee80211_get_sband(sdata);
 103        if (!sband)
 104                return changed;
 105
 106        if (sband->band == NL80211_BAND_5GHZ) {
 107                /* (IEEE 802.11-2012 19.4.5) */
 108                short_slot = true;
 109                goto out;
 110        } else if (sband->band != NL80211_BAND_2GHZ) {
 111                goto out;
 112        }
 113
 114        for (i = 0; i < sband->n_bitrates; i++)
 115                if (sband->bitrates[i].flags & IEEE80211_RATE_ERP_G)
 116                        erp_rates |= BIT(i);
 117
 118        if (!erp_rates)
 119                goto out;
 120
 121        rcu_read_lock();
 122        list_for_each_entry_rcu(sta, &local->sta_list, list) {
 123                if (sdata != sta->sdata ||
 124                    sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 125                        continue;
 126
 127                short_slot = false;
 128                if (erp_rates & sta->sta.supp_rates[sband->band])
 129                        short_slot = true;
 130                 else
 131                        break;
 132        }
 133        rcu_read_unlock();
 134
 135out:
 136        if (sdata->vif.bss_conf.use_short_slot != short_slot) {
 137                sdata->vif.bss_conf.use_short_slot = short_slot;
 138                changed = BSS_CHANGED_ERP_SLOT;
 139                mpl_dbg(sdata, "mesh_plink %pM: ERP short slot time %d\n",
 140                        sdata->vif.addr, short_slot);
 141        }
 142        return changed;
 143}
 144
 145/**
 146 * mesh_set_ht_prot_mode - set correct HT protection mode
 147 * @sdata: the (mesh) interface to handle
 148 *
 149 * Section 9.23.3.5 of IEEE 80211-2012 describes the protection rules for HT
 150 * mesh STA in a MBSS. Three HT protection modes are supported for now, non-HT
 151 * mixed mode, 20MHz-protection and no-protection mode. non-HT mixed mode is
 152 * selected if any non-HT peers are present in our MBSS.  20MHz-protection mode
 153 * is selected if all peers in our 20/40MHz MBSS support HT and atleast one
 154 * HT20 peer is present. Otherwise no-protection mode is selected.
 155 */
 156static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
 157{
 158        struct ieee80211_local *local = sdata->local;
 159        struct sta_info *sta;
 160        u16 ht_opmode;
 161        bool non_ht_sta = false, ht20_sta = false;
 162
 163        switch (sdata->vif.bss_conf.chandef.width) {
 164        case NL80211_CHAN_WIDTH_20_NOHT:
 165        case NL80211_CHAN_WIDTH_5:
 166        case NL80211_CHAN_WIDTH_10:
 167                return 0;
 168        default:
 169                break;
 170        }
 171
 172        rcu_read_lock();
 173        list_for_each_entry_rcu(sta, &local->sta_list, list) {
 174                if (sdata != sta->sdata ||
 175                    sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 176                        continue;
 177
 178                if (sta->sta.bandwidth > IEEE80211_STA_RX_BW_20)
 179                        continue;
 180
 181                if (!sta->sta.ht_cap.ht_supported) {
 182                        mpl_dbg(sdata, "nonHT sta (%pM) is present\n",
 183                                       sta->sta.addr);
 184                        non_ht_sta = true;
 185                        break;
 186                }
 187
 188                mpl_dbg(sdata, "HT20 sta (%pM) is present\n", sta->sta.addr);
 189                ht20_sta = true;
 190        }
 191        rcu_read_unlock();
 192
 193        if (non_ht_sta)
 194                ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
 195        else if (ht20_sta &&
 196                 sdata->vif.bss_conf.chandef.width > NL80211_CHAN_WIDTH_20)
 197                ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
 198        else
 199                ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
 200
 201        if (sdata->vif.bss_conf.ht_operation_mode == ht_opmode)
 202                return 0;
 203
 204        sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
 205        sdata->u.mesh.mshcfg.ht_opmode = ht_opmode;
 206        mpl_dbg(sdata, "selected new HT protection mode %d\n", ht_opmode);
 207        return BSS_CHANGED_HT;
 208}
 209
 210static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
 211                               struct sta_info *sta,
 212                               enum ieee80211_self_protected_actioncode action,
 213                               u8 *da, u16 llid, u16 plid, u16 reason)
 214{
 215        struct ieee80211_local *local = sdata->local;
 216        struct sk_buff *skb;
 217        struct ieee80211_tx_info *info;
 218        struct ieee80211_mgmt *mgmt;
 219        bool include_plid = false;
 220        u16 peering_proto = 0;
 221        u8 *pos, ie_len = 4;
 222        u8 ie_len_he_cap;
 223        int hdr_len = offsetofend(struct ieee80211_mgmt, u.action.u.self_prot);
 224        int err = -ENOMEM;
 225
 226        ie_len_he_cap = ieee80211_ie_len_he_cap(sdata,
 227                                                NL80211_IFTYPE_MESH_POINT);
 228        skb = dev_alloc_skb(local->tx_headroom +
 229                            hdr_len +
 230                            2 + /* capability info */
 231                            2 + /* AID */
 232                            2 + 8 + /* supported rates */
 233                            2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 234                            2 + sdata->u.mesh.mesh_id_len +
 235                            2 + sizeof(struct ieee80211_meshconf_ie) +
 236                            2 + sizeof(struct ieee80211_ht_cap) +
 237                            2 + sizeof(struct ieee80211_ht_operation) +
 238                            2 + sizeof(struct ieee80211_vht_cap) +
 239                            2 + sizeof(struct ieee80211_vht_operation) +
 240                            ie_len_he_cap +
 241                            2 + 1 + sizeof(struct ieee80211_he_operation) +
 242                                    sizeof(struct ieee80211_he_6ghz_oper) +
 243                            2 + 1 + sizeof(struct ieee80211_he_6ghz_capa) +
 244                            2 + 8 + /* peering IE */
 245                            sdata->u.mesh.ie_len);
 246        if (!skb)
 247                return err;
 248        info = IEEE80211_SKB_CB(skb);
 249        skb_reserve(skb, local->tx_headroom);
 250        mgmt = skb_put_zero(skb, hdr_len);
 251        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 252                                          IEEE80211_STYPE_ACTION);
 253        memcpy(mgmt->da, da, ETH_ALEN);
 254        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 255        memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 256        mgmt->u.action.category = WLAN_CATEGORY_SELF_PROTECTED;
 257        mgmt->u.action.u.self_prot.action_code = action;
 258
 259        if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 260                struct ieee80211_supported_band *sband;
 261                enum nl80211_band band;
 262
 263                sband = ieee80211_get_sband(sdata);
 264                if (!sband) {
 265                        err = -EINVAL;
 266                        goto free;
 267                }
 268                band = sband->band;
 269
 270                /* capability info */
 271                pos = skb_put_zero(skb, 2);
 272                if (action == WLAN_SP_MESH_PEERING_CONFIRM) {
 273                        /* AID */
 274                        pos = skb_put(skb, 2);
 275                        put_unaligned_le16(sta->sta.aid, pos);
 276                }
 277                if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
 278                    ieee80211_add_ext_srates_ie(sdata, skb, true, band) ||
 279                    mesh_add_rsn_ie(sdata, skb) ||
 280                    mesh_add_meshid_ie(sdata, skb) ||
 281                    mesh_add_meshconf_ie(sdata, skb))
 282                        goto free;
 283        } else {        /* WLAN_SP_MESH_PEERING_CLOSE */
 284                info->flags |= IEEE80211_TX_CTL_NO_ACK;
 285                if (mesh_add_meshid_ie(sdata, skb))
 286                        goto free;
 287        }
 288
 289        /* Add Mesh Peering Management element */
 290        switch (action) {
 291        case WLAN_SP_MESH_PEERING_OPEN:
 292                break;
 293        case WLAN_SP_MESH_PEERING_CONFIRM:
 294                ie_len += 2;
 295                include_plid = true;
 296                break;
 297        case WLAN_SP_MESH_PEERING_CLOSE:
 298                if (plid) {
 299                        ie_len += 2;
 300                        include_plid = true;
 301                }
 302                ie_len += 2;    /* reason code */
 303                break;
 304        default:
 305                err = -EINVAL;
 306                goto free;
 307        }
 308
 309        if (WARN_ON(skb_tailroom(skb) < 2 + ie_len))
 310                goto free;
 311
 312        pos = skb_put(skb, 2 + ie_len);
 313        *pos++ = WLAN_EID_PEER_MGMT;
 314        *pos++ = ie_len;
 315        memcpy(pos, &peering_proto, 2);
 316        pos += 2;
 317        put_unaligned_le16(llid, pos);
 318        pos += 2;
 319        if (include_plid) {
 320                put_unaligned_le16(plid, pos);
 321                pos += 2;
 322        }
 323        if (action == WLAN_SP_MESH_PEERING_CLOSE) {
 324                put_unaligned_le16(reason, pos);
 325                pos += 2;
 326        }
 327
 328        if (action != WLAN_SP_MESH_PEERING_CLOSE) {
 329                if (mesh_add_ht_cap_ie(sdata, skb) ||
 330                    mesh_add_ht_oper_ie(sdata, skb) ||
 331                    mesh_add_vht_cap_ie(sdata, skb) ||
 332                    mesh_add_vht_oper_ie(sdata, skb) ||
 333                    mesh_add_he_cap_ie(sdata, skb, ie_len_he_cap) ||
 334                    mesh_add_he_oper_ie(sdata, skb) ||
 335                    mesh_add_he_6ghz_cap_ie(sdata, skb))
 336                        goto free;
 337        }
 338
 339        if (mesh_add_vendor_ies(sdata, skb))
 340                goto free;
 341
 342        ieee80211_tx_skb(sdata, skb);
 343        return 0;
 344free:
 345        kfree_skb(skb);
 346        return err;
 347}
 348
 349/**
 350 * __mesh_plink_deactivate - deactivate mesh peer link
 351 *
 352 * @sta: mesh peer link to deactivate
 353 *
 354 * Mesh paths with this peer as next hop should be flushed
 355 * by the caller outside of plink_lock.
 356 *
 357 * Returns beacon changed flag if the beacon content changed.
 358 *
 359 * Locking: the caller must hold sta->mesh->plink_lock
 360 */
 361static u32 __mesh_plink_deactivate(struct sta_info *sta)
 362{
 363        struct ieee80211_sub_if_data *sdata = sta->sdata;
 364        u32 changed = 0;
 365
 366        lockdep_assert_held(&sta->mesh->plink_lock);
 367
 368        if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
 369                changed = mesh_plink_dec_estab_count(sdata);
 370        sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 371
 372        ieee80211_mps_sta_status_update(sta);
 373        changed |= ieee80211_mps_set_sta_local_pm(sta,
 374                        NL80211_MESH_POWER_UNKNOWN);
 375
 376        return changed;
 377}
 378
 379/**
 380 * mesh_plink_deactivate - deactivate mesh peer link
 381 *
 382 * @sta: mesh peer link to deactivate
 383 *
 384 * All mesh paths with this peer as next hop will be flushed
 385 */
 386u32 mesh_plink_deactivate(struct sta_info *sta)
 387{
 388        struct ieee80211_sub_if_data *sdata = sta->sdata;
 389        u32 changed;
 390
 391        spin_lock_bh(&sta->mesh->plink_lock);
 392        changed = __mesh_plink_deactivate(sta);
 393
 394        if (!sdata->u.mesh.user_mpm) {
 395                sta->mesh->reason = WLAN_REASON_MESH_PEER_CANCELED;
 396                mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_CLOSE,
 397                                    sta->sta.addr, sta->mesh->llid,
 398                                    sta->mesh->plid, sta->mesh->reason);
 399        }
 400        spin_unlock_bh(&sta->mesh->plink_lock);
 401        if (!sdata->u.mesh.user_mpm)
 402                del_timer_sync(&sta->mesh->plink_timer);
 403        mesh_path_flush_by_nexthop(sta);
 404
 405        /* make sure no readers can access nexthop sta from here on */
 406        synchronize_net();
 407
 408        return changed;
 409}
 410
 411static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
 412                               struct sta_info *sta,
 413                               struct ieee802_11_elems *elems)
 414{
 415        struct ieee80211_local *local = sdata->local;
 416        struct ieee80211_supported_band *sband;
 417        u32 rates, basic_rates = 0, changed = 0;
 418        enum ieee80211_sta_rx_bandwidth bw = sta->sta.bandwidth;
 419
 420        sband = ieee80211_get_sband(sdata);
 421        if (!sband)
 422                return;
 423
 424        rates = ieee80211_sta_get_rates(sdata, elems, sband->band,
 425                                        &basic_rates);
 426
 427        spin_lock_bh(&sta->mesh->plink_lock);
 428        sta->rx_stats.last_rx = jiffies;
 429
 430        /* rates and capabilities don't change during peering */
 431        if (sta->mesh->plink_state == NL80211_PLINK_ESTAB &&
 432            sta->mesh->processed_beacon)
 433                goto out;
 434        sta->mesh->processed_beacon = true;
 435
 436        if (sta->sta.supp_rates[sband->band] != rates)
 437                changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
 438        sta->sta.supp_rates[sband->band] = rates;
 439
 440        if (ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
 441                                              elems->ht_cap_elem, sta))
 442                changed |= IEEE80211_RC_BW_CHANGED;
 443
 444        ieee80211_vht_cap_ie_to_sta_vht_cap(sdata, sband,
 445                                            elems->vht_cap_elem, sta);
 446
 447        ieee80211_he_cap_ie_to_sta_he_cap(sdata, sband, elems->he_cap,
 448                                          elems->he_cap_len,
 449                                          elems->he_6ghz_capa,
 450                                          sta);
 451
 452        if (bw != sta->sta.bandwidth)
 453                changed |= IEEE80211_RC_BW_CHANGED;
 454
 455        /* HT peer is operating 20MHz-only */
 456        if (elems->ht_operation &&
 457            !(elems->ht_operation->ht_param &
 458              IEEE80211_HT_PARAM_CHAN_WIDTH_ANY)) {
 459                if (sta->sta.bandwidth != IEEE80211_STA_RX_BW_20)
 460                        changed |= IEEE80211_RC_BW_CHANGED;
 461                sta->sta.bandwidth = IEEE80211_STA_RX_BW_20;
 462        }
 463
 464        if (!test_sta_flag(sta, WLAN_STA_RATE_CONTROL))
 465                rate_control_rate_init(sta);
 466        else
 467                rate_control_rate_update(local, sband, sta, changed);
 468out:
 469        spin_unlock_bh(&sta->mesh->plink_lock);
 470}
 471
 472static int mesh_allocate_aid(struct ieee80211_sub_if_data *sdata)
 473{
 474        struct sta_info *sta;
 475        unsigned long *aid_map;
 476        int aid;
 477
 478        aid_map = kcalloc(BITS_TO_LONGS(IEEE80211_MAX_AID + 1),
 479                          sizeof(*aid_map), GFP_KERNEL);
 480        if (!aid_map)
 481                return -ENOMEM;
 482
 483        /* reserve aid 0 for mcast indication */
 484        __set_bit(0, aid_map);
 485
 486        rcu_read_lock();
 487        list_for_each_entry_rcu(sta, &sdata->local->sta_list, list)
 488                __set_bit(sta->sta.aid, aid_map);
 489        rcu_read_unlock();
 490
 491        aid = find_first_zero_bit(aid_map, IEEE80211_MAX_AID + 1);
 492        kfree(aid_map);
 493
 494        if (aid > IEEE80211_MAX_AID)
 495                return -ENOBUFS;
 496
 497        return aid;
 498}
 499
 500static struct sta_info *
 501__mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr)
 502{
 503        struct sta_info *sta;
 504        int aid;
 505
 506        if (sdata->local->num_sta >= MESH_MAX_PLINKS)
 507                return NULL;
 508
 509        aid = mesh_allocate_aid(sdata);
 510        if (aid < 0)
 511                return NULL;
 512
 513        sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
 514        if (!sta)
 515                return NULL;
 516
 517        sta->mesh->plink_state = NL80211_PLINK_LISTEN;
 518        sta->sta.wme = true;
 519        sta->sta.aid = aid;
 520
 521        sta_info_pre_move_state(sta, IEEE80211_STA_AUTH);
 522        sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC);
 523        sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED);
 524
 525        return sta;
 526}
 527
 528static struct sta_info *
 529mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr,
 530                    struct ieee802_11_elems *elems,
 531                    struct ieee80211_rx_status *rx_status)
 532{
 533        struct sta_info *sta = NULL;
 534
 535        /* Userspace handles station allocation */
 536        if (sdata->u.mesh.user_mpm ||
 537            sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
 538                if (mesh_peer_accepts_plinks(elems) &&
 539                    mesh_plink_availables(sdata)) {
 540                        int sig = 0;
 541
 542                        if (ieee80211_hw_check(&sdata->local->hw, SIGNAL_DBM))
 543                                sig = rx_status->signal;
 544
 545                        cfg80211_notify_new_peer_candidate(sdata->dev, addr,
 546                                                           elems->ie_start,
 547                                                           elems->total_len,
 548                                                           sig, GFP_KERNEL);
 549                }
 550        } else
 551                sta = __mesh_sta_info_alloc(sdata, addr);
 552
 553        return sta;
 554}
 555
 556/*
 557 * mesh_sta_info_get - return mesh sta info entry for @addr.
 558 *
 559 * @sdata: local meshif
 560 * @addr: peer's address
 561 * @elems: IEs from beacon or mesh peering frame.
 562 * @rx_status: rx status for the frame for signal reporting
 563 *
 564 * Return existing or newly allocated sta_info under RCU read lock.
 565 * (re)initialize with given IEs.
 566 */
 567static struct sta_info *
 568mesh_sta_info_get(struct ieee80211_sub_if_data *sdata,
 569                  u8 *addr, struct ieee802_11_elems *elems,
 570                  struct ieee80211_rx_status *rx_status) __acquires(RCU)
 571{
 572        struct sta_info *sta = NULL;
 573
 574        rcu_read_lock();
 575        sta = sta_info_get(sdata, addr);
 576        if (sta) {
 577                mesh_sta_info_init(sdata, sta, elems);
 578        } else {
 579                rcu_read_unlock();
 580                /* can't run atomic */
 581                sta = mesh_sta_info_alloc(sdata, addr, elems, rx_status);
 582                if (!sta) {
 583                        rcu_read_lock();
 584                        return NULL;
 585                }
 586
 587                mesh_sta_info_init(sdata, sta, elems);
 588
 589                if (sta_info_insert_rcu(sta))
 590                        return NULL;
 591        }
 592
 593        return sta;
 594}
 595
 596/*
 597 * mesh_neighbour_update - update or initialize new mesh neighbor.
 598 *
 599 * @sdata: local meshif
 600 * @addr: peer's address
 601 * @elems: IEs from beacon or mesh peering frame
 602 * @rx_status: rx status for the frame for signal reporting
 603 *
 604 * Initiates peering if appropriate.
 605 */
 606void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 607                           u8 *hw_addr,
 608                           struct ieee802_11_elems *elems,
 609                           struct ieee80211_rx_status *rx_status)
 610{
 611        struct sta_info *sta;
 612        u32 changed = 0;
 613
 614        sta = mesh_sta_info_get(sdata, hw_addr, elems, rx_status);
 615        if (!sta)
 616                goto out;
 617
 618        sta->mesh->connected_to_gate = elems->mesh_config->meshconf_form &
 619                IEEE80211_MESHCONF_FORM_CONNECTED_TO_GATE;
 620
 621        if (mesh_peer_accepts_plinks(elems) &&
 622            sta->mesh->plink_state == NL80211_PLINK_LISTEN &&
 623            sdata->u.mesh.accepting_plinks &&
 624            sdata->u.mesh.mshcfg.auto_open_plinks &&
 625            rssi_threshold_check(sdata, sta))
 626                changed = mesh_plink_open(sta);
 627
 628        ieee80211_mps_frame_release(sta, elems);
 629out:
 630        rcu_read_unlock();
 631        ieee80211_mbss_info_change_notify(sdata, changed);
 632}
 633
 634void mesh_plink_timer(struct timer_list *t)
 635{
 636        struct mesh_sta *mesh = from_timer(mesh, t, plink_timer);
 637        struct sta_info *sta;
 638        u16 reason = 0;
 639        struct ieee80211_sub_if_data *sdata;
 640        struct mesh_config *mshcfg;
 641        enum ieee80211_self_protected_actioncode action = 0;
 642
 643        /*
 644         * This STA is valid because sta_info_destroy() will
 645         * del_timer_sync() this timer after having made sure
 646         * it cannot be readded (by deleting the plink.)
 647         */
 648        sta = mesh->plink_sta;
 649
 650        if (sta->sdata->local->quiescing)
 651                return;
 652
 653        spin_lock_bh(&sta->mesh->plink_lock);
 654
 655        /* If a timer fires just before a state transition on another CPU,
 656         * we may have already extended the timeout and changed state by the
 657         * time we've acquired the lock and arrived  here.  In that case,
 658         * skip this timer and wait for the new one.
 659         */
 660        if (time_before(jiffies, sta->mesh->plink_timer.expires)) {
 661                mpl_dbg(sta->sdata,
 662                        "Ignoring timer for %pM in state %s (timer adjusted)",
 663                        sta->sta.addr, mplstates[sta->mesh->plink_state]);
 664                spin_unlock_bh(&sta->mesh->plink_lock);
 665                return;
 666        }
 667
 668        /* del_timer() and handler may race when entering these states */
 669        if (sta->mesh->plink_state == NL80211_PLINK_LISTEN ||
 670            sta->mesh->plink_state == NL80211_PLINK_ESTAB) {
 671                mpl_dbg(sta->sdata,
 672                        "Ignoring timer for %pM in state %s (timer deleted)",
 673                        sta->sta.addr, mplstates[sta->mesh->plink_state]);
 674                spin_unlock_bh(&sta->mesh->plink_lock);
 675                return;
 676        }
 677
 678        mpl_dbg(sta->sdata,
 679                "Mesh plink timer for %pM fired on state %s\n",
 680                sta->sta.addr, mplstates[sta->mesh->plink_state]);
 681        sdata = sta->sdata;
 682        mshcfg = &sdata->u.mesh.mshcfg;
 683
 684        switch (sta->mesh->plink_state) {
 685        case NL80211_PLINK_OPN_RCVD:
 686        case NL80211_PLINK_OPN_SNT:
 687                /* retry timer */
 688                if (sta->mesh->plink_retries < mshcfg->dot11MeshMaxRetries) {
 689                        u32 rand;
 690                        mpl_dbg(sta->sdata,
 691                                "Mesh plink for %pM (retry, timeout): %d %d\n",
 692                                sta->sta.addr, sta->mesh->plink_retries,
 693                                sta->mesh->plink_timeout);
 694                        get_random_bytes(&rand, sizeof(u32));
 695                        sta->mesh->plink_timeout = sta->mesh->plink_timeout +
 696                                             rand % sta->mesh->plink_timeout;
 697                        ++sta->mesh->plink_retries;
 698                        mod_plink_timer(sta, sta->mesh->plink_timeout);
 699                        action = WLAN_SP_MESH_PEERING_OPEN;
 700                        break;
 701                }
 702                reason = WLAN_REASON_MESH_MAX_RETRIES;
 703                fallthrough;
 704        case NL80211_PLINK_CNF_RCVD:
 705                /* confirm timer */
 706                if (!reason)
 707                        reason = WLAN_REASON_MESH_CONFIRM_TIMEOUT;
 708                sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 709                mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 710                action = WLAN_SP_MESH_PEERING_CLOSE;
 711                break;
 712        case NL80211_PLINK_HOLDING:
 713                /* holding timer */
 714                del_timer(&sta->mesh->plink_timer);
 715                mesh_plink_fsm_restart(sta);
 716                break;
 717        default:
 718                break;
 719        }
 720        spin_unlock_bh(&sta->mesh->plink_lock);
 721        if (action)
 722                mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 723                                    sta->mesh->llid, sta->mesh->plid, reason);
 724}
 725
 726static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
 727{
 728        sta->mesh->plink_timeout = timeout;
 729        mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
 730}
 731
 732static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
 733                        u16 llid)
 734{
 735        struct ieee80211_local *local = sdata->local;
 736        bool in_use = false;
 737        struct sta_info *sta;
 738
 739        rcu_read_lock();
 740        list_for_each_entry_rcu(sta, &local->sta_list, list) {
 741                if (sdata != sta->sdata)
 742                        continue;
 743
 744                if (!memcmp(&sta->mesh->llid, &llid, sizeof(llid))) {
 745                        in_use = true;
 746                        break;
 747                }
 748        }
 749        rcu_read_unlock();
 750
 751        return in_use;
 752}
 753
 754static u16 mesh_get_new_llid(struct ieee80211_sub_if_data *sdata)
 755{
 756        u16 llid;
 757
 758        do {
 759                get_random_bytes(&llid, sizeof(llid));
 760        } while (llid_in_use(sdata, llid));
 761
 762        return llid;
 763}
 764
 765u32 mesh_plink_open(struct sta_info *sta)
 766{
 767        struct ieee80211_sub_if_data *sdata = sta->sdata;
 768        u32 changed;
 769
 770        if (!test_sta_flag(sta, WLAN_STA_AUTH))
 771                return 0;
 772
 773        spin_lock_bh(&sta->mesh->plink_lock);
 774        sta->mesh->llid = mesh_get_new_llid(sdata);
 775        if (sta->mesh->plink_state != NL80211_PLINK_LISTEN &&
 776            sta->mesh->plink_state != NL80211_PLINK_BLOCKED) {
 777                spin_unlock_bh(&sta->mesh->plink_lock);
 778                return 0;
 779        }
 780        sta->mesh->plink_state = NL80211_PLINK_OPN_SNT;
 781        mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);
 782        spin_unlock_bh(&sta->mesh->plink_lock);
 783        mpl_dbg(sdata,
 784                "Mesh plink: starting establishment with %pM\n",
 785                sta->sta.addr);
 786
 787        /* set the non-peer mode to active during peering */
 788        changed = ieee80211_mps_local_status_update(sdata);
 789
 790        mesh_plink_frame_tx(sdata, sta, WLAN_SP_MESH_PEERING_OPEN,
 791                            sta->sta.addr, sta->mesh->llid, 0, 0);
 792        return changed;
 793}
 794
 795u32 mesh_plink_block(struct sta_info *sta)
 796{
 797        u32 changed;
 798
 799        spin_lock_bh(&sta->mesh->plink_lock);
 800        changed = __mesh_plink_deactivate(sta);
 801        sta->mesh->plink_state = NL80211_PLINK_BLOCKED;
 802        spin_unlock_bh(&sta->mesh->plink_lock);
 803        mesh_path_flush_by_nexthop(sta);
 804
 805        return changed;
 806}
 807
 808static void mesh_plink_close(struct ieee80211_sub_if_data *sdata,
 809                             struct sta_info *sta,
 810                             enum plink_event event)
 811{
 812        struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 813        u16 reason = (event == CLS_ACPT) ?
 814                     WLAN_REASON_MESH_CLOSE : WLAN_REASON_MESH_CONFIG;
 815
 816        sta->mesh->reason = reason;
 817        sta->mesh->plink_state = NL80211_PLINK_HOLDING;
 818        mod_plink_timer(sta, mshcfg->dot11MeshHoldingTimeout);
 819}
 820
 821static u32 mesh_plink_establish(struct ieee80211_sub_if_data *sdata,
 822                                struct sta_info *sta)
 823{
 824        struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 825        u32 changed = 0;
 826
 827        del_timer(&sta->mesh->plink_timer);
 828        sta->mesh->plink_state = NL80211_PLINK_ESTAB;
 829        changed |= mesh_plink_inc_estab_count(sdata);
 830        changed |= mesh_set_ht_prot_mode(sdata);
 831        changed |= mesh_set_short_slot_time(sdata);
 832        mpl_dbg(sdata, "Mesh plink with %pM ESTABLISHED\n", sta->sta.addr);
 833        ieee80211_mps_sta_status_update(sta);
 834        changed |= ieee80211_mps_set_sta_local_pm(sta, mshcfg->power_mode);
 835        return changed;
 836}
 837
 838/**
 839 * mesh_plink_fsm - step @sta MPM based on @event
 840 *
 841 * @sdata: interface
 842 * @sta: mesh neighbor
 843 * @event: peering event
 844 *
 845 * Return: changed MBSS flags
 846 */
 847static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata,
 848                          struct sta_info *sta, enum plink_event event)
 849{
 850        struct mesh_config *mshcfg = &sdata->u.mesh.mshcfg;
 851        enum ieee80211_self_protected_actioncode action = 0;
 852        u32 changed = 0;
 853        bool flush = false;
 854
 855        mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,
 856                mplstates[sta->mesh->plink_state], mplevents[event]);
 857
 858        spin_lock_bh(&sta->mesh->plink_lock);
 859        switch (sta->mesh->plink_state) {
 860        case NL80211_PLINK_LISTEN:
 861                switch (event) {
 862                case CLS_ACPT:
 863                        mesh_plink_fsm_restart(sta);
 864                        break;
 865                case OPN_ACPT:
 866                        sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 867                        sta->mesh->llid = mesh_get_new_llid(sdata);
 868                        mesh_plink_timer_set(sta,
 869                                             mshcfg->dot11MeshRetryTimeout);
 870
 871                        /* set the non-peer mode to active during peering */
 872                        changed |= ieee80211_mps_local_status_update(sdata);
 873                        action = WLAN_SP_MESH_PEERING_OPEN;
 874                        break;
 875                default:
 876                        break;
 877                }
 878                break;
 879        case NL80211_PLINK_OPN_SNT:
 880                switch (event) {
 881                case OPN_RJCT:
 882                case CNF_RJCT:
 883                case CLS_ACPT:
 884                        mesh_plink_close(sdata, sta, event);
 885                        action = WLAN_SP_MESH_PEERING_CLOSE;
 886                        break;
 887                case OPN_ACPT:
 888                        /* retry timer is left untouched */
 889                        sta->mesh->plink_state = NL80211_PLINK_OPN_RCVD;
 890                        action = WLAN_SP_MESH_PEERING_CONFIRM;
 891                        break;
 892                case CNF_ACPT:
 893                        sta->mesh->plink_state = NL80211_PLINK_CNF_RCVD;
 894                        mod_plink_timer(sta, mshcfg->dot11MeshConfirmTimeout);
 895                        break;
 896                default:
 897                        break;
 898                }
 899                break;
 900        case NL80211_PLINK_OPN_RCVD:
 901                switch (event) {
 902                case OPN_RJCT:
 903                case CNF_RJCT:
 904                case CLS_ACPT:
 905                        mesh_plink_close(sdata, sta, event);
 906                        action = WLAN_SP_MESH_PEERING_CLOSE;
 907                        break;
 908                case OPN_ACPT:
 909                        action = WLAN_SP_MESH_PEERING_CONFIRM;
 910                        break;
 911                case CNF_ACPT:
 912                        changed |= mesh_plink_establish(sdata, sta);
 913                        break;
 914                default:
 915                        break;
 916                }
 917                break;
 918        case NL80211_PLINK_CNF_RCVD:
 919                switch (event) {
 920                case OPN_RJCT:
 921                case CNF_RJCT:
 922                case CLS_ACPT:
 923                        mesh_plink_close(sdata, sta, event);
 924                        action = WLAN_SP_MESH_PEERING_CLOSE;
 925                        break;
 926                case OPN_ACPT:
 927                        changed |= mesh_plink_establish(sdata, sta);
 928                        action = WLAN_SP_MESH_PEERING_CONFIRM;
 929                        break;
 930                default:
 931                        break;
 932                }
 933                break;
 934        case NL80211_PLINK_ESTAB:
 935                switch (event) {
 936                case CLS_ACPT:
 937                        changed |= __mesh_plink_deactivate(sta);
 938                        changed |= mesh_set_ht_prot_mode(sdata);
 939                        changed |= mesh_set_short_slot_time(sdata);
 940                        mesh_plink_close(sdata, sta, event);
 941                        action = WLAN_SP_MESH_PEERING_CLOSE;
 942                        flush = true;
 943                        break;
 944                case OPN_ACPT:
 945                        action = WLAN_SP_MESH_PEERING_CONFIRM;
 946                        break;
 947                default:
 948                        break;
 949                }
 950                break;
 951        case NL80211_PLINK_HOLDING:
 952                switch (event) {
 953                case CLS_ACPT:
 954                        del_timer(&sta->mesh->plink_timer);
 955                        mesh_plink_fsm_restart(sta);
 956                        break;
 957                case OPN_ACPT:
 958                case CNF_ACPT:
 959                case OPN_RJCT:
 960                case CNF_RJCT:
 961                        action = WLAN_SP_MESH_PEERING_CLOSE;
 962                        break;
 963                default:
 964                        break;
 965                }
 966                break;
 967        default:
 968                /* should not get here, PLINK_BLOCKED is dealt with at the
 969                 * beginning of the function
 970                 */
 971                break;
 972        }
 973        spin_unlock_bh(&sta->mesh->plink_lock);
 974        if (flush)
 975                mesh_path_flush_by_nexthop(sta);
 976        if (action) {
 977                mesh_plink_frame_tx(sdata, sta, action, sta->sta.addr,
 978                                    sta->mesh->llid, sta->mesh->plid,
 979                                    sta->mesh->reason);
 980
 981                /* also send confirm in open case */
 982                if (action == WLAN_SP_MESH_PEERING_OPEN) {
 983                        mesh_plink_frame_tx(sdata, sta,
 984                                            WLAN_SP_MESH_PEERING_CONFIRM,
 985                                            sta->sta.addr, sta->mesh->llid,
 986                                            sta->mesh->plid, 0);
 987                }
 988        }
 989
 990        return changed;
 991}
 992
 993/*
 994 * mesh_plink_get_event - get correct MPM event
 995 *
 996 * @sdata: interface
 997 * @sta: peer, leave NULL if processing a frame from a new suitable peer
 998 * @elems: peering management IEs
 999 * @ftype: frame type
1000 * @llid: peer's peer link ID
1001 * @plid: peer's local link ID
1002 *
1003 * Return: new peering event for @sta, but PLINK_UNDEFINED should be treated as
1004 * an error.
1005 */
1006static enum plink_event
1007mesh_plink_get_event(struct ieee80211_sub_if_data *sdata,
1008                     struct sta_info *sta,
1009                     struct ieee802_11_elems *elems,
1010                     enum ieee80211_self_protected_actioncode ftype,
1011                     u16 llid, u16 plid)
1012{
1013        enum plink_event event = PLINK_UNDEFINED;
1014        u8 ie_len = elems->peering_len;
1015        bool matches_local;
1016
1017        matches_local = (ftype == WLAN_SP_MESH_PEERING_CLOSE ||
1018                         mesh_matches_local(sdata, elems));
1019
1020        /* deny open request from non-matching peer */
1021        if (!matches_local && !sta) {
1022                event = OPN_RJCT;
1023                goto out;
1024        }
1025
1026        if (!sta) {
1027                if (ftype != WLAN_SP_MESH_PEERING_OPEN) {
1028                        mpl_dbg(sdata, "Mesh plink: cls or cnf from unknown peer\n");
1029                        goto out;
1030                }
1031                /* ftype == WLAN_SP_MESH_PEERING_OPEN */
1032                if (!mesh_plink_free_count(sdata)) {
1033                        mpl_dbg(sdata, "Mesh plink error: no more free plinks\n");
1034                        goto out;
1035                }
1036
1037                /* new matching peer */
1038                event = OPN_ACPT;
1039                goto out;
1040        } else {
1041                if (!test_sta_flag(sta, WLAN_STA_AUTH)) {
1042                        mpl_dbg(sdata, "Mesh plink: Action frame from non-authed peer\n");
1043                        goto out;
1044                }
1045                if (sta->mesh->plink_state == NL80211_PLINK_BLOCKED)
1046                        goto out;
1047        }
1048
1049        switch (ftype) {
1050        case WLAN_SP_MESH_PEERING_OPEN:
1051                if (!matches_local)
1052                        event = OPN_RJCT;
1053                if (!mesh_plink_free_count(sdata) ||
1054                    (sta->mesh->plid && sta->mesh->plid != plid))
1055                        event = OPN_IGNR;
1056                else
1057                        event = OPN_ACPT;
1058                break;
1059        case WLAN_SP_MESH_PEERING_CONFIRM:
1060                if (!matches_local)
1061                        event = CNF_RJCT;
1062                if (!mesh_plink_free_count(sdata) ||
1063                    sta->mesh->llid != llid ||
1064                    (sta->mesh->plid && sta->mesh->plid != plid))
1065                        event = CNF_IGNR;
1066                else
1067                        event = CNF_ACPT;
1068                break;
1069        case WLAN_SP_MESH_PEERING_CLOSE:
1070                if (sta->mesh->plink_state == NL80211_PLINK_ESTAB)
1071                        /* Do not check for llid or plid. This does not
1072                         * follow the standard but since multiple plinks
1073                         * per sta are not supported, it is necessary in
1074                         * order to avoid a livelock when MP A sees an
1075                         * establish peer link to MP B but MP B does not
1076                         * see it. This can be caused by a timeout in
1077                         * B's peer link establishment or B beign
1078                         * restarted.
1079                         */
1080                        event = CLS_ACPT;
1081                else if (sta->mesh->plid != plid)
1082                        event = CLS_IGNR;
1083                else if (ie_len == 8 && sta->mesh->llid != llid)
1084                        event = CLS_IGNR;
1085                else
1086                        event = CLS_ACPT;
1087                break;
1088        default:
1089                mpl_dbg(sdata, "Mesh plink: unknown frame subtype\n");
1090                break;
1091        }
1092
1093out:
1094        return event;
1095}
1096
1097static void
1098mesh_process_plink_frame(struct ieee80211_sub_if_data *sdata,
1099                         struct ieee80211_mgmt *mgmt,
1100                         struct ieee802_11_elems *elems,
1101                         struct ieee80211_rx_status *rx_status)
1102{
1103
1104        struct sta_info *sta;
1105        enum plink_event event;
1106        enum ieee80211_self_protected_actioncode ftype;
1107        u32 changed = 0;
1108        u8 ie_len = elems->peering_len;
1109        u16 plid, llid = 0;
1110
1111        if (!elems->peering) {
1112                mpl_dbg(sdata,
1113                        "Mesh plink: missing necessary peer link ie\n");
1114                return;
1115        }
1116
1117        if (elems->rsn_len &&
1118            sdata->u.mesh.security == IEEE80211_MESH_SEC_NONE) {
1119                mpl_dbg(sdata,
1120                        "Mesh plink: can't establish link with secure peer\n");
1121                return;
1122        }
1123
1124        ftype = mgmt->u.action.u.self_prot.action_code;
1125        if ((ftype == WLAN_SP_MESH_PEERING_OPEN && ie_len != 4) ||
1126            (ftype == WLAN_SP_MESH_PEERING_CONFIRM && ie_len != 6) ||
1127            (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len != 6
1128                                                        && ie_len != 8)) {
1129                mpl_dbg(sdata,
1130                        "Mesh plink: incorrect plink ie length %d %d\n",
1131                        ftype, ie_len);
1132                return;
1133        }
1134
1135        if (ftype != WLAN_SP_MESH_PEERING_CLOSE &&
1136            (!elems->mesh_id || !elems->mesh_config)) {
1137                mpl_dbg(sdata, "Mesh plink: missing necessary ie\n");
1138                return;
1139        }
1140        /* Note the lines below are correct, the llid in the frame is the plid
1141         * from the point of view of this host.
1142         */
1143        plid = get_unaligned_le16(PLINK_GET_LLID(elems->peering));
1144        if (ftype == WLAN_SP_MESH_PEERING_CONFIRM ||
1145            (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8))
1146                llid = get_unaligned_le16(PLINK_GET_PLID(elems->peering));
1147
1148        /* WARNING: Only for sta pointer, is dropped & re-acquired */
1149        rcu_read_lock();
1150
1151        sta = sta_info_get(sdata, mgmt->sa);
1152
1153        if (ftype == WLAN_SP_MESH_PEERING_OPEN &&
1154            !rssi_threshold_check(sdata, sta)) {
1155                mpl_dbg(sdata, "Mesh plink: %pM does not meet rssi threshold\n",
1156                        mgmt->sa);
1157                goto unlock_rcu;
1158        }
1159
1160        /* Now we will figure out the appropriate event... */
1161        event = mesh_plink_get_event(sdata, sta, elems, ftype, llid, plid);
1162
1163        if (event == OPN_ACPT) {
1164                rcu_read_unlock();
1165                /* allocate sta entry if necessary and update info */
1166                sta = mesh_sta_info_get(sdata, mgmt->sa, elems, rx_status);
1167                if (!sta) {
1168                        mpl_dbg(sdata, "Mesh plink: failed to init peer!\n");
1169                        goto unlock_rcu;
1170                }
1171                sta->mesh->plid = plid;
1172        } else if (!sta && event == OPN_RJCT) {
1173                mesh_plink_frame_tx(sdata, NULL, WLAN_SP_MESH_PEERING_CLOSE,
1174                                    mgmt->sa, 0, plid,
1175                                    WLAN_REASON_MESH_CONFIG);
1176                goto unlock_rcu;
1177        } else if (!sta || event == PLINK_UNDEFINED) {
1178                /* something went wrong */
1179                goto unlock_rcu;
1180        }
1181
1182        if (event == CNF_ACPT) {
1183                /* 802.11-2012 13.3.7.2 - update plid on CNF if not set */
1184                if (!sta->mesh->plid)
1185                        sta->mesh->plid = plid;
1186
1187                sta->mesh->aid = get_unaligned_le16(PLINK_CNF_AID(mgmt));
1188        }
1189
1190        changed |= mesh_plink_fsm(sdata, sta, event);
1191
1192unlock_rcu:
1193        rcu_read_unlock();
1194
1195        if (changed)
1196                ieee80211_mbss_info_change_notify(sdata, changed);
1197}
1198
1199void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata,
1200                         struct ieee80211_mgmt *mgmt, size_t len,
1201                         struct ieee80211_rx_status *rx_status)
1202{
1203        struct ieee802_11_elems elems;
1204        size_t baselen;
1205        u8 *baseaddr;
1206
1207        /* need action_code, aux */
1208        if (len < IEEE80211_MIN_ACTION_SIZE + 3)
1209                return;
1210
1211        if (sdata->u.mesh.user_mpm)
1212                /* userspace must register for these */
1213                return;
1214
1215        if (is_multicast_ether_addr(mgmt->da)) {
1216                mpl_dbg(sdata,
1217                        "Mesh plink: ignore frame from multicast address\n");
1218                return;
1219        }
1220
1221        baseaddr = mgmt->u.action.u.self_prot.variable;
1222        baselen = (u8 *) mgmt->u.action.u.self_prot.variable - (u8 *) mgmt;
1223        if (mgmt->u.action.u.self_prot.action_code ==
1224                                                WLAN_SP_MESH_PEERING_CONFIRM) {
1225                baseaddr += 4;
1226                baselen += 4;
1227
1228                if (baselen > len)
1229                        return;
1230        }
1231        ieee802_11_parse_elems(baseaddr, len - baselen, true, &elems,
1232                               mgmt->bssid, NULL);
1233        mesh_process_plink_frame(sdata, mgmt, &elems, rx_status);
1234}
1235