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