linux/net/mac80211/mesh_hwmp.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
  10#include <linux/slab.h>
  11#include <linux/etherdevice.h>
  12#include <asm/unaligned.h>
  13#include "wme.h"
  14#include "mesh.h"
  15
  16#define TEST_FRAME_LEN  8192
  17#define MAX_METRIC      0xffffffff
  18#define ARITH_SHIFT     8
  19
  20#define MAX_PREQ_QUEUE_LEN      64
  21
  22/* Destination only */
  23#define MP_F_DO 0x1
  24/* Reply and forward */
  25#define MP_F_RF 0x2
  26/* Unknown Sequence Number */
  27#define MP_F_USN    0x01
  28/* Reason code Present */
  29#define MP_F_RCODE  0x02
  30
  31static void mesh_queue_preq(struct mesh_path *, u8);
  32
  33static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
  34{
  35        if (ae)
  36                offset += 6;
  37        return get_unaligned_le32(preq_elem + offset);
  38}
  39
  40static inline u32 u16_field_get(const u8 *preq_elem, int offset, bool ae)
  41{
  42        if (ae)
  43                offset += 6;
  44        return get_unaligned_le16(preq_elem + offset);
  45}
  46
  47/* HWMP IE processing macros */
  48#define AE_F                    (1<<6)
  49#define AE_F_SET(x)             (*x & AE_F)
  50#define PREQ_IE_FLAGS(x)        (*(x))
  51#define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  52#define PREQ_IE_TTL(x)          (*(x + 2))
  53#define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  54#define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  55#define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  56#define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  57#define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  58#define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  59#define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  60#define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  61
  62
  63#define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  64#define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  65#define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  66#define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  67#define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  68#define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  69#define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  70#define PREP_IE_TARGET_ADDR(x)  (x + 3)
  71#define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  72
  73#define PERR_IE_TTL(x)          (*(x))
  74#define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  75#define PERR_IE_TARGET_ADDR(x)  (x + 3)
  76#define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  77#define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  78
  79#define MSEC_TO_TU(x) (x*1000/1024)
  80#define SN_GT(x, y) ((s32)(y - x) < 0)
  81#define SN_LT(x, y) ((s32)(x - y) < 0)
  82
  83#define net_traversal_jiffies(s) \
  84        msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  85#define default_lifetime(s) \
  86        MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  87#define min_preq_int_jiff(s) \
  88        (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  89#define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  90#define disc_timeout_jiff(s) \
  91        msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  92#define root_path_confirmation_jiffies(s) \
  93        msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  94
  95enum mpath_frame_type {
  96        MPATH_PREQ = 0,
  97        MPATH_PREP,
  98        MPATH_PERR,
  99        MPATH_RANN
 100};
 101
 102static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 103
 104static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 105                                  const u8 *orig_addr, __le32 orig_sn,
 106                                  u8 target_flags, const u8 *target,
 107                                  __le32 target_sn, const u8 *da,
 108                                  u8 hop_count, u8 ttl,
 109                                  __le32 lifetime, __le32 metric,
 110                                  __le32 preq_id,
 111                                  struct ieee80211_sub_if_data *sdata)
 112{
 113        struct ieee80211_local *local = sdata->local;
 114        struct sk_buff *skb;
 115        struct ieee80211_mgmt *mgmt;
 116        u8 *pos, ie_len;
 117        int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 118                      sizeof(mgmt->u.action.u.mesh_action);
 119
 120        skb = dev_alloc_skb(local->tx_headroom +
 121                            hdr_len +
 122                            2 + 37); /* max HWMP IE */
 123        if (!skb)
 124                return -1;
 125        skb_reserve(skb, local->tx_headroom);
 126        mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 127        memset(mgmt, 0, hdr_len);
 128        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 129                                          IEEE80211_STYPE_ACTION);
 130
 131        memcpy(mgmt->da, da, ETH_ALEN);
 132        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 133        /* BSSID == SA */
 134        memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 135        mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 136        mgmt->u.action.u.mesh_action.action_code =
 137                                        WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 138
 139        switch (action) {
 140        case MPATH_PREQ:
 141                mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 142                ie_len = 37;
 143                pos = skb_put(skb, 2 + ie_len);
 144                *pos++ = WLAN_EID_PREQ;
 145                break;
 146        case MPATH_PREP:
 147                mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
 148                ie_len = 31;
 149                pos = skb_put(skb, 2 + ie_len);
 150                *pos++ = WLAN_EID_PREP;
 151                break;
 152        case MPATH_RANN:
 153                mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 154                ie_len = sizeof(struct ieee80211_rann_ie);
 155                pos = skb_put(skb, 2 + ie_len);
 156                *pos++ = WLAN_EID_RANN;
 157                break;
 158        default:
 159                kfree_skb(skb);
 160                return -ENOTSUPP;
 161                break;
 162        }
 163        *pos++ = ie_len;
 164        *pos++ = flags;
 165        *pos++ = hop_count;
 166        *pos++ = ttl;
 167        if (action == MPATH_PREP) {
 168                memcpy(pos, target, ETH_ALEN);
 169                pos += ETH_ALEN;
 170                memcpy(pos, &target_sn, 4);
 171                pos += 4;
 172        } else {
 173                if (action == MPATH_PREQ) {
 174                        memcpy(pos, &preq_id, 4);
 175                        pos += 4;
 176                }
 177                memcpy(pos, orig_addr, ETH_ALEN);
 178                pos += ETH_ALEN;
 179                memcpy(pos, &orig_sn, 4);
 180                pos += 4;
 181        }
 182        memcpy(pos, &lifetime, 4);      /* interval for RANN */
 183        pos += 4;
 184        memcpy(pos, &metric, 4);
 185        pos += 4;
 186        if (action == MPATH_PREQ) {
 187                *pos++ = 1; /* destination count */
 188                *pos++ = target_flags;
 189                memcpy(pos, target, ETH_ALEN);
 190                pos += ETH_ALEN;
 191                memcpy(pos, &target_sn, 4);
 192                pos += 4;
 193        } else if (action == MPATH_PREP) {
 194                memcpy(pos, orig_addr, ETH_ALEN);
 195                pos += ETH_ALEN;
 196                memcpy(pos, &orig_sn, 4);
 197                pos += 4;
 198        }
 199
 200        ieee80211_tx_skb(sdata, skb);
 201        return 0;
 202}
 203
 204
 205/*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 206 *  headroom in case the frame is encrypted. */
 207static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 208                struct sk_buff *skb)
 209{
 210        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 211        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 212
 213        skb_set_mac_header(skb, 0);
 214        skb_set_network_header(skb, 0);
 215        skb_set_transport_header(skb, 0);
 216
 217        /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 218        skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 219        skb->priority = 7;
 220
 221        info->control.vif = &sdata->vif;
 222        info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 223        ieee80211_set_qos_hdr(sdata, skb);
 224        ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
 225}
 226
 227/**
 228 * mesh_path_error_tx - Sends a PERR mesh management frame
 229 *
 230 * @ttl: allowed remaining hops
 231 * @target: broken destination
 232 * @target_sn: SN of the broken destination
 233 * @target_rcode: reason code for this PERR
 234 * @ra: node this frame is addressed to
 235 * @sdata: local mesh subif
 236 *
 237 * Note: This function may be called with driver locks taken that the driver
 238 * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 239 * frame directly but add it to the pending queue instead.
 240 */
 241int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 242                       u8 ttl, const u8 *target, __le32 target_sn,
 243                       __le16 target_rcode, const u8 *ra)
 244{
 245        struct ieee80211_local *local = sdata->local;
 246        struct sk_buff *skb;
 247        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 248        struct ieee80211_mgmt *mgmt;
 249        u8 *pos, ie_len;
 250        int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 251                      sizeof(mgmt->u.action.u.mesh_action);
 252
 253        if (time_before(jiffies, ifmsh->next_perr))
 254                return -EAGAIN;
 255
 256        skb = dev_alloc_skb(local->tx_headroom +
 257                            IEEE80211_ENCRYPT_HEADROOM +
 258                            IEEE80211_ENCRYPT_TAILROOM +
 259                            hdr_len +
 260                            2 + 15 /* PERR IE */);
 261        if (!skb)
 262                return -1;
 263        skb_reserve(skb, local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM);
 264        mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 265        memset(mgmt, 0, hdr_len);
 266        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 267                                          IEEE80211_STYPE_ACTION);
 268
 269        memcpy(mgmt->da, ra, ETH_ALEN);
 270        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 271        /* BSSID == SA */
 272        memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 273        mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 274        mgmt->u.action.u.mesh_action.action_code =
 275                                        WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 276        ie_len = 15;
 277        pos = skb_put(skb, 2 + ie_len);
 278        *pos++ = WLAN_EID_PERR;
 279        *pos++ = ie_len;
 280        /* ttl */
 281        *pos++ = ttl;
 282        /* number of destinations */
 283        *pos++ = 1;
 284        /*
 285         * flags bit, bit 1 is unset if we know the sequence number and
 286         * bit 2 is set if we have a reason code
 287         */
 288        *pos = 0;
 289        if (!target_sn)
 290                *pos |= MP_F_USN;
 291        if (target_rcode)
 292                *pos |= MP_F_RCODE;
 293        pos++;
 294        memcpy(pos, target, ETH_ALEN);
 295        pos += ETH_ALEN;
 296        memcpy(pos, &target_sn, 4);
 297        pos += 4;
 298        memcpy(pos, &target_rcode, 2);
 299
 300        /* see note in function header */
 301        prepare_frame_for_deferred_tx(sdata, skb);
 302        ifmsh->next_perr = TU_TO_EXP_TIME(
 303                                   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 304        ieee80211_add_pending_skb(local, skb);
 305        return 0;
 306}
 307
 308void ieee80211s_update_metric(struct ieee80211_local *local,
 309                struct sta_info *sta, struct sk_buff *skb)
 310{
 311        struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 312        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 313        int failed;
 314
 315        if (!ieee80211_is_data(hdr->frame_control))
 316                return;
 317
 318        failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 319
 320        /* moving average, scaled to 100 */
 321        sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
 322        if (sta->fail_avg > 95)
 323                mesh_plink_broken(sta);
 324}
 325
 326static u32 airtime_link_metric_get(struct ieee80211_local *local,
 327                                   struct sta_info *sta)
 328{
 329        struct rate_info rinfo;
 330        /* This should be adjusted for each device */
 331        int device_constant = 1 << ARITH_SHIFT;
 332        int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 333        int s_unit = 1 << ARITH_SHIFT;
 334        int rate, err;
 335        u32 tx_time, estimated_retx;
 336        u64 result;
 337
 338        if (sta->fail_avg >= 100)
 339                return MAX_METRIC;
 340
 341        sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
 342        rate = cfg80211_calculate_bitrate(&rinfo);
 343        if (WARN_ON(!rate))
 344                return MAX_METRIC;
 345
 346        err = (sta->fail_avg << ARITH_SHIFT) / 100;
 347
 348        /* bitrate is in units of 100 Kbps, while we need rate in units of
 349         * 1Mbps. This will be corrected on tx_time computation.
 350         */
 351        tx_time = (device_constant + 10 * test_frame_len / rate);
 352        estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 353        result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 354        return (u32)result;
 355}
 356
 357/**
 358 * hwmp_route_info_get - Update routing info to originator and transmitter
 359 *
 360 * @sdata: local mesh subif
 361 * @mgmt: mesh management frame
 362 * @hwmp_ie: hwmp information element (PREP or PREQ)
 363 * @action: type of hwmp ie
 364 *
 365 * This function updates the path routing information to the originator and the
 366 * transmitter of a HWMP PREQ or PREP frame.
 367 *
 368 * Returns: metric to frame originator or 0 if the frame should not be further
 369 * processed
 370 *
 371 * Notes: this function is the only place (besides user-provided info) where
 372 * path routing information is updated.
 373 */
 374static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 375                               struct ieee80211_mgmt *mgmt,
 376                               const u8 *hwmp_ie, enum mpath_frame_type action)
 377{
 378        struct ieee80211_local *local = sdata->local;
 379        struct mesh_path *mpath;
 380        struct sta_info *sta;
 381        bool fresh_info;
 382        const u8 *orig_addr, *ta;
 383        u32 orig_sn, orig_metric;
 384        unsigned long orig_lifetime, exp_time;
 385        u32 last_hop_metric, new_metric;
 386        bool process = true;
 387
 388        rcu_read_lock();
 389        sta = sta_info_get(sdata, mgmt->sa);
 390        if (!sta) {
 391                rcu_read_unlock();
 392                return 0;
 393        }
 394
 395        last_hop_metric = airtime_link_metric_get(local, sta);
 396        /* Update and check originator routing info */
 397        fresh_info = true;
 398
 399        switch (action) {
 400        case MPATH_PREQ:
 401                orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 402                orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 403                orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 404                orig_metric = PREQ_IE_METRIC(hwmp_ie);
 405                break;
 406        case MPATH_PREP:
 407                /* Originator here refers to the MP that was the target in the
 408                 * Path Request. We divert from the nomenclature in the draft
 409                 * so that we can easily use a single function to gather path
 410                 * information from both PREQ and PREP frames.
 411                 */
 412                orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 413                orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 414                orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 415                orig_metric = PREP_IE_METRIC(hwmp_ie);
 416                break;
 417        default:
 418                rcu_read_unlock();
 419                return 0;
 420        }
 421        new_metric = orig_metric + last_hop_metric;
 422        if (new_metric < orig_metric)
 423                new_metric = MAX_METRIC;
 424        exp_time = TU_TO_EXP_TIME(orig_lifetime);
 425
 426        if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 427                /* This MP is the originator, we are not interested in this
 428                 * frame, except for updating transmitter's path info.
 429                 */
 430                process = false;
 431                fresh_info = false;
 432        } else {
 433                mpath = mesh_path_lookup(sdata, orig_addr);
 434                if (mpath) {
 435                        spin_lock_bh(&mpath->state_lock);
 436                        if (mpath->flags & MESH_PATH_FIXED)
 437                                fresh_info = false;
 438                        else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 439                            (mpath->flags & MESH_PATH_SN_VALID)) {
 440                                if (SN_GT(mpath->sn, orig_sn) ||
 441                                    (mpath->sn == orig_sn &&
 442                                     new_metric >= mpath->metric)) {
 443                                        process = false;
 444                                        fresh_info = false;
 445                                }
 446                        }
 447                } else {
 448                        mpath = mesh_path_add(sdata, orig_addr);
 449                        if (IS_ERR(mpath)) {
 450                                rcu_read_unlock();
 451                                return 0;
 452                        }
 453                        spin_lock_bh(&mpath->state_lock);
 454                }
 455
 456                if (fresh_info) {
 457                        mesh_path_assign_nexthop(mpath, sta);
 458                        mpath->flags |= MESH_PATH_SN_VALID;
 459                        mpath->metric = new_metric;
 460                        mpath->sn = orig_sn;
 461                        mpath->exp_time = time_after(mpath->exp_time, exp_time)
 462                                          ?  mpath->exp_time : exp_time;
 463                        mesh_path_activate(mpath);
 464                        spin_unlock_bh(&mpath->state_lock);
 465                        mesh_path_tx_pending(mpath);
 466                        /* draft says preq_id should be saved to, but there does
 467                         * not seem to be any use for it, skipping by now
 468                         */
 469                } else
 470                        spin_unlock_bh(&mpath->state_lock);
 471        }
 472
 473        /* Update and check transmitter routing info */
 474        ta = mgmt->sa;
 475        if (ether_addr_equal(orig_addr, ta))
 476                fresh_info = false;
 477        else {
 478                fresh_info = true;
 479
 480                mpath = mesh_path_lookup(sdata, ta);
 481                if (mpath) {
 482                        spin_lock_bh(&mpath->state_lock);
 483                        if ((mpath->flags & MESH_PATH_FIXED) ||
 484                                ((mpath->flags & MESH_PATH_ACTIVE) &&
 485                                        (last_hop_metric > mpath->metric)))
 486                                fresh_info = false;
 487                } else {
 488                        mpath = mesh_path_add(sdata, ta);
 489                        if (IS_ERR(mpath)) {
 490                                rcu_read_unlock();
 491                                return 0;
 492                        }
 493                        spin_lock_bh(&mpath->state_lock);
 494                }
 495
 496                if (fresh_info) {
 497                        mesh_path_assign_nexthop(mpath, sta);
 498                        mpath->metric = last_hop_metric;
 499                        mpath->exp_time = time_after(mpath->exp_time, exp_time)
 500                                          ?  mpath->exp_time : exp_time;
 501                        mesh_path_activate(mpath);
 502                        spin_unlock_bh(&mpath->state_lock);
 503                        mesh_path_tx_pending(mpath);
 504                } else
 505                        spin_unlock_bh(&mpath->state_lock);
 506        }
 507
 508        rcu_read_unlock();
 509
 510        return process ? new_metric : 0;
 511}
 512
 513static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 514                                    struct ieee80211_mgmt *mgmt,
 515                                    const u8 *preq_elem, u32 metric)
 516{
 517        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 518        struct mesh_path *mpath = NULL;
 519        const u8 *target_addr, *orig_addr;
 520        const u8 *da;
 521        u8 target_flags, ttl, flags;
 522        u32 orig_sn, target_sn, lifetime, orig_metric;
 523        bool reply = false;
 524        bool forward = true;
 525        bool root_is_gate;
 526
 527        /* Update target SN, if present */
 528        target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 529        orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 530        target_sn = PREQ_IE_TARGET_SN(preq_elem);
 531        orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 532        target_flags = PREQ_IE_TARGET_F(preq_elem);
 533        orig_metric = metric;
 534        /* Proactive PREQ gate announcements */
 535        flags = PREQ_IE_FLAGS(preq_elem);
 536        root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 537
 538        mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 539
 540        if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 541                mhwmp_dbg(sdata, "PREQ is for us\n");
 542                forward = false;
 543                reply = true;
 544                metric = 0;
 545                if (time_after(jiffies, ifmsh->last_sn_update +
 546                                        net_traversal_jiffies(sdata)) ||
 547                    time_before(jiffies, ifmsh->last_sn_update)) {
 548                        target_sn = ++ifmsh->sn;
 549                        ifmsh->last_sn_update = jiffies;
 550                }
 551        } else if (is_broadcast_ether_addr(target_addr) &&
 552                   (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 553                rcu_read_lock();
 554                mpath = mesh_path_lookup(sdata, orig_addr);
 555                if (mpath) {
 556                        if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 557                                reply = true;
 558                                target_addr = sdata->vif.addr;
 559                                target_sn = ++ifmsh->sn;
 560                                metric = 0;
 561                                ifmsh->last_sn_update = jiffies;
 562                        }
 563                        if (root_is_gate)
 564                                mesh_path_add_gate(mpath);
 565                }
 566                rcu_read_unlock();
 567        } else {
 568                rcu_read_lock();
 569                mpath = mesh_path_lookup(sdata, target_addr);
 570                if (mpath) {
 571                        if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 572                                        SN_LT(mpath->sn, target_sn)) {
 573                                mpath->sn = target_sn;
 574                                mpath->flags |= MESH_PATH_SN_VALID;
 575                        } else if ((!(target_flags & MP_F_DO)) &&
 576                                        (mpath->flags & MESH_PATH_ACTIVE)) {
 577                                reply = true;
 578                                metric = mpath->metric;
 579                                target_sn = mpath->sn;
 580                                if (target_flags & MP_F_RF)
 581                                        target_flags |= MP_F_DO;
 582                                else
 583                                        forward = false;
 584                        }
 585                }
 586                rcu_read_unlock();
 587        }
 588
 589        if (reply) {
 590                lifetime = PREQ_IE_LIFETIME(preq_elem);
 591                ttl = ifmsh->mshcfg.element_ttl;
 592                if (ttl != 0) {
 593                        mhwmp_dbg(sdata, "replying to the PREQ\n");
 594                        mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 595                                cpu_to_le32(orig_sn), 0, target_addr,
 596                                cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 597                                cpu_to_le32(lifetime), cpu_to_le32(metric),
 598                                0, sdata);
 599                } else {
 600                        ifmsh->mshstats.dropped_frames_ttl++;
 601                }
 602        }
 603
 604        if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 605                u32 preq_id;
 606                u8 hopcount;
 607
 608                ttl = PREQ_IE_TTL(preq_elem);
 609                lifetime = PREQ_IE_LIFETIME(preq_elem);
 610                if (ttl <= 1) {
 611                        ifmsh->mshstats.dropped_frames_ttl++;
 612                        return;
 613                }
 614                mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 615                --ttl;
 616                preq_id = PREQ_IE_PREQ_ID(preq_elem);
 617                hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 618                da = (mpath && mpath->is_root) ?
 619                        mpath->rann_snd_addr : broadcast_addr;
 620
 621                if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 622                        target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 623                        target_sn = PREQ_IE_TARGET_SN(preq_elem);
 624                        metric = orig_metric;
 625                }
 626
 627                mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 628                                cpu_to_le32(orig_sn), target_flags, target_addr,
 629                                cpu_to_le32(target_sn), da,
 630                                hopcount, ttl, cpu_to_le32(lifetime),
 631                                cpu_to_le32(metric), cpu_to_le32(preq_id),
 632                                sdata);
 633                if (!is_multicast_ether_addr(da))
 634                        ifmsh->mshstats.fwded_unicast++;
 635                else
 636                        ifmsh->mshstats.fwded_mcast++;
 637                ifmsh->mshstats.fwded_frames++;
 638        }
 639}
 640
 641
 642static inline struct sta_info *
 643next_hop_deref_protected(struct mesh_path *mpath)
 644{
 645        return rcu_dereference_protected(mpath->next_hop,
 646                                         lockdep_is_held(&mpath->state_lock));
 647}
 648
 649
 650static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 651                                    struct ieee80211_mgmt *mgmt,
 652                                    const u8 *prep_elem, u32 metric)
 653{
 654        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 655        struct mesh_path *mpath;
 656        const u8 *target_addr, *orig_addr;
 657        u8 ttl, hopcount, flags;
 658        u8 next_hop[ETH_ALEN];
 659        u32 target_sn, orig_sn, lifetime;
 660
 661        mhwmp_dbg(sdata, "received PREP from %pM\n",
 662                  PREP_IE_TARGET_ADDR(prep_elem));
 663
 664        orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 665        if (ether_addr_equal(orig_addr, sdata->vif.addr))
 666                /* destination, no forwarding required */
 667                return;
 668
 669        if (!ifmsh->mshcfg.dot11MeshForwarding)
 670                return;
 671
 672        ttl = PREP_IE_TTL(prep_elem);
 673        if (ttl <= 1) {
 674                sdata->u.mesh.mshstats.dropped_frames_ttl++;
 675                return;
 676        }
 677
 678        rcu_read_lock();
 679        mpath = mesh_path_lookup(sdata, orig_addr);
 680        if (mpath)
 681                spin_lock_bh(&mpath->state_lock);
 682        else
 683                goto fail;
 684        if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 685                spin_unlock_bh(&mpath->state_lock);
 686                goto fail;
 687        }
 688        memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 689        spin_unlock_bh(&mpath->state_lock);
 690        --ttl;
 691        flags = PREP_IE_FLAGS(prep_elem);
 692        lifetime = PREP_IE_LIFETIME(prep_elem);
 693        hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 694        target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 695        target_sn = PREP_IE_TARGET_SN(prep_elem);
 696        orig_sn = PREP_IE_ORIG_SN(prep_elem);
 697
 698        mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 699                cpu_to_le32(orig_sn), 0, target_addr,
 700                cpu_to_le32(target_sn), next_hop, hopcount,
 701                ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 702                0, sdata);
 703        rcu_read_unlock();
 704
 705        sdata->u.mesh.mshstats.fwded_unicast++;
 706        sdata->u.mesh.mshstats.fwded_frames++;
 707        return;
 708
 709fail:
 710        rcu_read_unlock();
 711        sdata->u.mesh.mshstats.dropped_frames_no_route++;
 712}
 713
 714static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 715                                    struct ieee80211_mgmt *mgmt,
 716                                    const u8 *perr_elem)
 717{
 718        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 719        struct mesh_path *mpath;
 720        u8 ttl;
 721        const u8 *ta, *target_addr;
 722        u32 target_sn;
 723        u16 target_rcode;
 724
 725        ta = mgmt->sa;
 726        ttl = PERR_IE_TTL(perr_elem);
 727        if (ttl <= 1) {
 728                ifmsh->mshstats.dropped_frames_ttl++;
 729                return;
 730        }
 731        ttl--;
 732        target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 733        target_sn = PERR_IE_TARGET_SN(perr_elem);
 734        target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 735
 736        rcu_read_lock();
 737        mpath = mesh_path_lookup(sdata, target_addr);
 738        if (mpath) {
 739                struct sta_info *sta;
 740
 741                spin_lock_bh(&mpath->state_lock);
 742                sta = next_hop_deref_protected(mpath);
 743                if (mpath->flags & MESH_PATH_ACTIVE &&
 744                    ether_addr_equal(ta, sta->sta.addr) &&
 745                    (!(mpath->flags & MESH_PATH_SN_VALID) ||
 746                    SN_GT(target_sn, mpath->sn))) {
 747                        mpath->flags &= ~MESH_PATH_ACTIVE;
 748                        mpath->sn = target_sn;
 749                        spin_unlock_bh(&mpath->state_lock);
 750                        if (!ifmsh->mshcfg.dot11MeshForwarding)
 751                                goto endperr;
 752                        mesh_path_error_tx(sdata, ttl, target_addr,
 753                                           cpu_to_le32(target_sn),
 754                                           cpu_to_le16(target_rcode),
 755                                           broadcast_addr);
 756                } else
 757                        spin_unlock_bh(&mpath->state_lock);
 758        }
 759endperr:
 760        rcu_read_unlock();
 761}
 762
 763static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 764                                    struct ieee80211_mgmt *mgmt,
 765                                    const struct ieee80211_rann_ie *rann)
 766{
 767        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 768        struct ieee80211_local *local = sdata->local;
 769        struct sta_info *sta;
 770        struct mesh_path *mpath;
 771        u8 ttl, flags, hopcount;
 772        const u8 *orig_addr;
 773        u32 orig_sn, metric, metric_txsta, interval;
 774        bool root_is_gate;
 775
 776        ttl = rann->rann_ttl;
 777        flags = rann->rann_flags;
 778        root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 779        orig_addr = rann->rann_addr;
 780        orig_sn = le32_to_cpu(rann->rann_seq);
 781        interval = le32_to_cpu(rann->rann_interval);
 782        hopcount = rann->rann_hopcount;
 783        hopcount++;
 784        metric = le32_to_cpu(rann->rann_metric);
 785
 786        /*  Ignore our own RANNs */
 787        if (ether_addr_equal(orig_addr, sdata->vif.addr))
 788                return;
 789
 790        mhwmp_dbg(sdata,
 791                  "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 792                  orig_addr, mgmt->sa, root_is_gate);
 793
 794        rcu_read_lock();
 795        sta = sta_info_get(sdata, mgmt->sa);
 796        if (!sta) {
 797                rcu_read_unlock();
 798                return;
 799        }
 800
 801        metric_txsta = airtime_link_metric_get(local, sta);
 802
 803        mpath = mesh_path_lookup(sdata, orig_addr);
 804        if (!mpath) {
 805                mpath = mesh_path_add(sdata, orig_addr);
 806                if (IS_ERR(mpath)) {
 807                        rcu_read_unlock();
 808                        sdata->u.mesh.mshstats.dropped_frames_no_route++;
 809                        return;
 810                }
 811        }
 812
 813        if (!(SN_LT(mpath->sn, orig_sn)) &&
 814            !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 815                rcu_read_unlock();
 816                return;
 817        }
 818
 819        if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 820             (time_after(jiffies, mpath->last_preq_to_root +
 821                                  root_path_confirmation_jiffies(sdata)) ||
 822             time_before(jiffies, mpath->last_preq_to_root))) &&
 823             !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 824                mhwmp_dbg(sdata,
 825                          "time to refresh root mpath %pM\n",
 826                          orig_addr);
 827                mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 828                mpath->last_preq_to_root = jiffies;
 829        }
 830
 831        mpath->sn = orig_sn;
 832        mpath->rann_metric = metric + metric_txsta;
 833        mpath->is_root = true;
 834        /* Recording RANNs sender address to send individually
 835         * addressed PREQs destined for root mesh STA */
 836        memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 837
 838        if (root_is_gate)
 839                mesh_path_add_gate(mpath);
 840
 841        if (ttl <= 1) {
 842                ifmsh->mshstats.dropped_frames_ttl++;
 843                rcu_read_unlock();
 844                return;
 845        }
 846        ttl--;
 847
 848        if (ifmsh->mshcfg.dot11MeshForwarding) {
 849                mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 850                                       cpu_to_le32(orig_sn),
 851                                       0, NULL, 0, broadcast_addr,
 852                                       hopcount, ttl, cpu_to_le32(interval),
 853                                       cpu_to_le32(metric + metric_txsta),
 854                                       0, sdata);
 855        }
 856
 857        rcu_read_unlock();
 858}
 859
 860
 861void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 862                            struct ieee80211_mgmt *mgmt, size_t len)
 863{
 864        struct ieee802_11_elems elems;
 865        size_t baselen;
 866        u32 last_hop_metric;
 867        struct sta_info *sta;
 868
 869        /* need action_code */
 870        if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 871                return;
 872
 873        rcu_read_lock();
 874        sta = sta_info_get(sdata, mgmt->sa);
 875        if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 876                rcu_read_unlock();
 877                return;
 878        }
 879        rcu_read_unlock();
 880
 881        baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 882        ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 883                               len - baselen, false, &elems);
 884
 885        if (elems.preq) {
 886                if (elems.preq_len != 37)
 887                        /* Right now we support just 1 destination and no AE */
 888                        return;
 889                last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 890                                                      MPATH_PREQ);
 891                if (last_hop_metric)
 892                        hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 893                                                last_hop_metric);
 894        }
 895        if (elems.prep) {
 896                if (elems.prep_len != 31)
 897                        /* Right now we support no AE */
 898                        return;
 899                last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 900                                                      MPATH_PREP);
 901                if (last_hop_metric)
 902                        hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 903                                                last_hop_metric);
 904        }
 905        if (elems.perr) {
 906                if (elems.perr_len != 15)
 907                        /* Right now we support only one destination per PERR */
 908                        return;
 909                hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 910        }
 911        if (elems.rann)
 912                hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 913}
 914
 915/**
 916 * mesh_queue_preq - queue a PREQ to a given destination
 917 *
 918 * @mpath: mesh path to discover
 919 * @flags: special attributes of the PREQ to be sent
 920 *
 921 * Locking: the function must be called from within a rcu read lock block.
 922 *
 923 */
 924static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 925{
 926        struct ieee80211_sub_if_data *sdata = mpath->sdata;
 927        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 928        struct mesh_preq_queue *preq_node;
 929
 930        preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 931        if (!preq_node) {
 932                mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 933                return;
 934        }
 935
 936        spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 937        if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 938                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 939                kfree(preq_node);
 940                if (printk_ratelimit())
 941                        mhwmp_dbg(sdata, "PREQ node queue full\n");
 942                return;
 943        }
 944
 945        spin_lock(&mpath->state_lock);
 946        if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 947                spin_unlock(&mpath->state_lock);
 948                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 949                kfree(preq_node);
 950                return;
 951        }
 952
 953        memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 954        preq_node->flags = flags;
 955
 956        mpath->flags |= MESH_PATH_REQ_QUEUED;
 957        spin_unlock(&mpath->state_lock);
 958
 959        list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 960        ++ifmsh->preq_queue_len;
 961        spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 962
 963        if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 964                ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 965
 966        else if (time_before(jiffies, ifmsh->last_preq)) {
 967                /* avoid long wait if did not send preqs for a long time
 968                 * and jiffies wrapped around
 969                 */
 970                ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 971                ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 972        } else
 973                mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 974                                                min_preq_int_jiff(sdata));
 975}
 976
 977/**
 978 * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 979 *
 980 * @sdata: local mesh subif
 981 */
 982void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 983{
 984        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 985        struct mesh_preq_queue *preq_node;
 986        struct mesh_path *mpath;
 987        u8 ttl, target_flags;
 988        const u8 *da;
 989        u32 lifetime;
 990
 991        spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 992        if (!ifmsh->preq_queue_len ||
 993                time_before(jiffies, ifmsh->last_preq +
 994                                min_preq_int_jiff(sdata))) {
 995                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 996                return;
 997        }
 998
 999        preq_node = list_first_entry(&ifmsh->preq_queue.list,
1000                        struct mesh_preq_queue, list);
1001        list_del(&preq_node->list);
1002        --ifmsh->preq_queue_len;
1003        spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1004
1005        rcu_read_lock();
1006        mpath = mesh_path_lookup(sdata, preq_node->dst);
1007        if (!mpath)
1008                goto enddiscovery;
1009
1010        spin_lock_bh(&mpath->state_lock);
1011        mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1012        if (preq_node->flags & PREQ_Q_F_START) {
1013                if (mpath->flags & MESH_PATH_RESOLVING) {
1014                        spin_unlock_bh(&mpath->state_lock);
1015                        goto enddiscovery;
1016                } else {
1017                        mpath->flags &= ~MESH_PATH_RESOLVED;
1018                        mpath->flags |= MESH_PATH_RESOLVING;
1019                        mpath->discovery_retries = 0;
1020                        mpath->discovery_timeout = disc_timeout_jiff(sdata);
1021                }
1022        } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1023                        mpath->flags & MESH_PATH_RESOLVED) {
1024                mpath->flags &= ~MESH_PATH_RESOLVING;
1025                spin_unlock_bh(&mpath->state_lock);
1026                goto enddiscovery;
1027        }
1028
1029        ifmsh->last_preq = jiffies;
1030
1031        if (time_after(jiffies, ifmsh->last_sn_update +
1032                                net_traversal_jiffies(sdata)) ||
1033            time_before(jiffies, ifmsh->last_sn_update)) {
1034                ++ifmsh->sn;
1035                sdata->u.mesh.last_sn_update = jiffies;
1036        }
1037        lifetime = default_lifetime(sdata);
1038        ttl = sdata->u.mesh.mshcfg.element_ttl;
1039        if (ttl == 0) {
1040                sdata->u.mesh.mshstats.dropped_frames_ttl++;
1041                spin_unlock_bh(&mpath->state_lock);
1042                goto enddiscovery;
1043        }
1044
1045        if (preq_node->flags & PREQ_Q_F_REFRESH)
1046                target_flags = MP_F_DO;
1047        else
1048                target_flags = MP_F_RF;
1049
1050        spin_unlock_bh(&mpath->state_lock);
1051        da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1052        mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1053                        cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1054                        cpu_to_le32(mpath->sn), da, 0,
1055                        ttl, cpu_to_le32(lifetime), 0,
1056                        cpu_to_le32(ifmsh->preq_id++), sdata);
1057        mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1058
1059enddiscovery:
1060        rcu_read_unlock();
1061        kfree(preq_node);
1062}
1063
1064/**
1065 * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1066 *
1067 * @skb: 802.11 frame to be sent
1068 * @sdata: network subif the frame will be sent through
1069 *
1070 * Lookup next hop for given skb and start path discovery if no
1071 * forwarding information is found.
1072 *
1073 * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1074 * skb is freeed here if no mpath could be allocated.
1075 */
1076int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1077                         struct sk_buff *skb)
1078{
1079        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1080        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1081        struct mesh_path *mpath;
1082        struct sk_buff *skb_to_free = NULL;
1083        u8 *target_addr = hdr->addr3;
1084        int err = 0;
1085
1086        /* Nulls are only sent to peers for PS and should be pre-addressed */
1087        if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1088                return 0;
1089
1090        rcu_read_lock();
1091        err = mesh_nexthop_lookup(sdata, skb);
1092        if (!err)
1093                goto endlookup;
1094
1095        /* no nexthop found, start resolving */
1096        mpath = mesh_path_lookup(sdata, target_addr);
1097        if (!mpath) {
1098                mpath = mesh_path_add(sdata, target_addr);
1099                if (IS_ERR(mpath)) {
1100                        mesh_path_discard_frame(sdata, skb);
1101                        err = PTR_ERR(mpath);
1102                        goto endlookup;
1103                }
1104        }
1105
1106        if (!(mpath->flags & MESH_PATH_RESOLVING))
1107                mesh_queue_preq(mpath, PREQ_Q_F_START);
1108
1109        if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1110                skb_to_free = skb_dequeue(&mpath->frame_queue);
1111
1112        info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1113        ieee80211_set_qos_hdr(sdata, skb);
1114        skb_queue_tail(&mpath->frame_queue, skb);
1115        err = -ENOENT;
1116        if (skb_to_free)
1117                mesh_path_discard_frame(sdata, skb_to_free);
1118
1119endlookup:
1120        rcu_read_unlock();
1121        return err;
1122}
1123
1124/**
1125 * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1126 * this function is considered "using" the associated mpath, so preempt a path
1127 * refresh if this mpath expires soon.
1128 *
1129 * @skb: 802.11 frame to be sent
1130 * @sdata: network subif the frame will be sent through
1131 *
1132 * Returns: 0 if the next hop was found. Nonzero otherwise.
1133 */
1134int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1135                        struct sk_buff *skb)
1136{
1137        struct mesh_path *mpath;
1138        struct sta_info *next_hop;
1139        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1140        u8 *target_addr = hdr->addr3;
1141        int err = -ENOENT;
1142
1143        rcu_read_lock();
1144        mpath = mesh_path_lookup(sdata, target_addr);
1145
1146        if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1147                goto endlookup;
1148
1149        if (time_after(jiffies,
1150                       mpath->exp_time -
1151                       msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1152            ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1153            !(mpath->flags & MESH_PATH_RESOLVING) &&
1154            !(mpath->flags & MESH_PATH_FIXED))
1155                mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1156
1157        next_hop = rcu_dereference(mpath->next_hop);
1158        if (next_hop) {
1159                memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1160                memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1161                ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1162                err = 0;
1163        }
1164
1165endlookup:
1166        rcu_read_unlock();
1167        return err;
1168}
1169
1170void mesh_path_timer(unsigned long data)
1171{
1172        struct mesh_path *mpath = (void *) data;
1173        struct ieee80211_sub_if_data *sdata = mpath->sdata;
1174        int ret;
1175
1176        if (sdata->local->quiescing)
1177                return;
1178
1179        spin_lock_bh(&mpath->state_lock);
1180        if (mpath->flags & MESH_PATH_RESOLVED ||
1181                        (!(mpath->flags & MESH_PATH_RESOLVING))) {
1182                mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1183                spin_unlock_bh(&mpath->state_lock);
1184        } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1185                ++mpath->discovery_retries;
1186                mpath->discovery_timeout *= 2;
1187                mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1188                spin_unlock_bh(&mpath->state_lock);
1189                mesh_queue_preq(mpath, 0);
1190        } else {
1191                mpath->flags = 0;
1192                mpath->exp_time = jiffies;
1193                spin_unlock_bh(&mpath->state_lock);
1194                if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1195                        ret = mesh_path_send_to_gates(mpath);
1196                        if (ret)
1197                                mhwmp_dbg(sdata, "no gate was reachable\n");
1198                } else
1199                        mesh_path_flush_pending(mpath);
1200        }
1201}
1202
1203void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1204{
1205        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1206        u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1207        u8 flags, target_flags = 0;
1208
1209        flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1210                        ? RANN_FLAG_IS_GATE : 0;
1211
1212        switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1213        case IEEE80211_PROACTIVE_RANN:
1214                mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1215                               cpu_to_le32(++ifmsh->sn),
1216                               0, NULL, 0, broadcast_addr,
1217                               0, ifmsh->mshcfg.element_ttl,
1218                               cpu_to_le32(interval), 0, 0, sdata);
1219                break;
1220        case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1221                flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1222        case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1223                interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1224                target_flags |= IEEE80211_PREQ_TO_FLAG |
1225                                IEEE80211_PREQ_USN_FLAG;
1226                mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1227                                cpu_to_le32(++ifmsh->sn), target_flags,
1228                                (u8 *) broadcast_addr, 0, broadcast_addr,
1229                                0, ifmsh->mshcfg.element_ttl,
1230                                cpu_to_le32(interval),
1231                                0, cpu_to_le32(ifmsh->preq_id++), sdata);
1232                break;
1233        default:
1234                mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1235                return;
1236        }
1237}
1238