Pileus Git - ~andy/linux/blob - net/mac80211/mesh_hwmp.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/slab.h>
  11 #include "wme.h"
  12 #include "mesh.h"
  13
  14 #ifdef CONFIG_MAC80211_VERBOSE_MHWMP_DEBUG
  15 #define mhwmp_dbg(fmt, args...) \
  16         printk(KERN_DEBUG "Mesh HWMP (%s): " fmt "\n", sdata->name, ##args)
  17 #else
  18 #define mhwmp_dbg(fmt, args...)   do { (void)(0); } while (0)
  19 #endif
  20
  21 #define TEST_FRAME_LEN  8192
  22 #define MAX_METRIC      0xffffffff
  23 #define ARITH_SHIFT     8
  24
  25 /* Number of frames buffered per destination for unresolved destinations */
  26 #define MESH_FRAME_QUEUE_LEN    10
  27 #define MAX_PREQ_QUEUE_LEN      64
  28
  29 /* Destination only */
  30 #define MP_F_DO 0x1
  31 /* Reply and forward */
  32 #define MP_F_RF 0x2
  33 /* Unknown Sequence Number */
  34 #define MP_F_USN    0x01
  35 /* Reason code Present */
  36 #define MP_F_RCODE  0x02
  37
  38 static void mesh_queue_preq(struct mesh_path *, u8);
  39
  40 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
  41 {
  42         if (ae)
  43                 offset += 6;
  44         return get_unaligned_le32(preq_elem + offset);
  45 }
  46
  47 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
  48 {
  49         if (ae)
  50                 offset += 6;
  51         return get_unaligned_le16(preq_elem + offset);
  52 }
  53
  54 /* HWMP IE processing macros */
  55 #define AE_F                    (1<<6)
  56 #define AE_F_SET(x)             (*x & AE_F)
  57 #define PREQ_IE_FLAGS(x)        (*(x))
  58 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  59 #define PREQ_IE_TTL(x)          (*(x + 2))
  60 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  61 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  62 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  63 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  64 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  65 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  66 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  67 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  68
  69
  70 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  71 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  72 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  73 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  74 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  75 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  76 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  77 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  78 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  79
  80 #define PERR_IE_TTL(x)          (*(x))
  81 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  82 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  83 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  84 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  85
  86 #define MSEC_TO_TU(x) (x*1000/1024)
  87 #define SN_GT(x, y) ((long) (y) - (long) (x) < 0)
  88 #define SN_LT(x, y) ((long) (x) - (long) (y) < 0)
  89
  90 #define net_traversal_jiffies(s) \
  91         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  92 #define default_lifetime(s) \
  93         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  94 #define min_preq_int_jiff(s) \
  95         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  96 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  97 #define disc_timeout_jiff(s) \
  98         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  99
 100 enum mpath_frame_type {
 101         MPATH_PREQ = 0,
 102         MPATH_PREP,
 103         MPATH_PERR,
 104         MPATH_RANN
 105 };
 106
 107 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 108
 109 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 110                 u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
 111                 __le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
 112                 __le32 lifetime, __le32 metric, __le32 preq_id,
 113                 struct ieee80211_sub_if_data *sdata)
 114 {
 115         struct ieee80211_local *local = sdata->local;
 116         struct sk_buff *skb;
 117         struct ieee80211_mgmt *mgmt;
 118         u8 *pos, ie_len;
 119         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 120                       sizeof(mgmt->u.action.u.mesh_action);
 121
 122         skb = dev_alloc_skb(local->tx_headroom +
 123                             hdr_len +
 124                             2 + 37); /* max HWMP IE */
 125         if (!skb)
 126                 return -1;
 127         skb_reserve(skb, local->tx_headroom);
 128         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 129         memset(mgmt, 0, hdr_len);
 130         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 131                                           IEEE80211_STYPE_ACTION);
 132
 133         memcpy(mgmt->da, da, ETH_ALEN);
 134         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 135         /* BSSID == SA */
 136         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 137         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 138         mgmt->u.action.u.mesh_action.action_code =
 139                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 140
 141         switch (action) {
 142         case MPATH_PREQ:
 143                 mhwmp_dbg("sending PREQ to %pM", target);
 144                 ie_len = 37;
 145                 pos = skb_put(skb, 2 + ie_len);
 146                 *pos++ = WLAN_EID_PREQ;
 147                 break;
 148         case MPATH_PREP:
 149                 mhwmp_dbg("sending PREP to %pM", target);
 150                 ie_len = 31;
 151                 pos = skb_put(skb, 2 + ie_len);
 152                 *pos++ = WLAN_EID_PREP;
 153                 break;
 154         case MPATH_RANN:
 155                 mhwmp_dbg("sending RANN from %pM", orig_addr);
 156                 ie_len = sizeof(struct ieee80211_rann_ie);
 157                 pos = skb_put(skb, 2 + ie_len);
 158                 *pos++ = WLAN_EID_RANN;
 159                 break;
 160         default:
 161                 kfree_skb(skb);
 162                 return -ENOTSUPP;
 163                 break;
 164         }
 165         *pos++ = ie_len;
 166         *pos++ = flags;
 167         *pos++ = hop_count;
 168         *pos++ = ttl;
 169         if (action == MPATH_PREP) {
 170                 memcpy(pos, target, ETH_ALEN);
 171                 pos += ETH_ALEN;
 172                 memcpy(pos, &target_sn, 4);
 173                 pos += 4;
 174         } else {
 175                 if (action == MPATH_PREQ) {
 176                         memcpy(pos, &preq_id, 4);
 177                         pos += 4;
 178                 }
 179                 memcpy(pos, orig_addr, ETH_ALEN);
 180                 pos += ETH_ALEN;
 181                 memcpy(pos, &orig_sn, 4);
 182                 pos += 4;
 183         }
 184         memcpy(pos, &lifetime, 4);      /* interval for RANN */
 185         pos += 4;
 186         memcpy(pos, &metric, 4);
 187         pos += 4;
 188         if (action == MPATH_PREQ) {
 189                 *pos++ = 1; /* destination count */
 190                 *pos++ = target_flags;
 191                 memcpy(pos, target, ETH_ALEN);
 192                 pos += ETH_ALEN;
 193                 memcpy(pos, &target_sn, 4);
 194                 pos += 4;
 195         } else if (action == MPATH_PREP) {
 196                 memcpy(pos, orig_addr, ETH_ALEN);
 197                 pos += ETH_ALEN;
 198                 memcpy(pos, &orig_sn, 4);
 199                 pos += 4;
 200         }
 201
 202         ieee80211_tx_skb(sdata, skb);
 203         return 0;
 204 }
 205
 206
 207 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 208  *  headroom in case the frame is encrypted. */
 209 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 210                 struct sk_buff *skb)
 211 {
 212         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 213
 214         skb_set_mac_header(skb, 0);
 215         skb_set_network_header(skb, 0);
 216         skb_set_transport_header(skb, 0);
 217
 218         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 219         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 220         skb->priority = 7;
 221
 222         info->control.vif = &sdata->vif;
 223         ieee80211_set_qos_hdr(sdata, skb);
 224 }
 225
 226 /**
 227  * mesh_send_path error - Sends a PERR mesh management frame
 228  *
 229  * @target: broken destination
 230  * @target_sn: SN of the broken destination
 231  * @target_rcode: reason code for this PERR
 232  * @ra: node this frame is addressed to
 233  *
 234  * Note: This function may be called with driver locks taken that the driver
 235  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 236  * frame directly but add it to the pending queue instead.
 237  */
 238 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 239                        __le16 target_rcode, const u8 *ra,
 240                        struct ieee80211_sub_if_data *sdata)
 241 {
 242         struct ieee80211_local *local = sdata->local;
 243         struct sk_buff *skb;
 244         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 245         struct ieee80211_mgmt *mgmt;
 246         u8 *pos, ie_len;
 247         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 248                       sizeof(mgmt->u.action.u.mesh_action);
 249
 250         if (time_before(jiffies, ifmsh->next_perr))
 251                 return -EAGAIN;
 252
 253         skb = dev_alloc_skb(local->tx_headroom +
 254                             hdr_len +
 255                             2 + 15 /* PERR IE */);
 256         if (!skb)
 257                 return -1;
 258         skb_reserve(skb, local->tx_headroom);
 259         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 260         memset(mgmt, 0, hdr_len);
 261         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 262                                           IEEE80211_STYPE_ACTION);
 263
 264         memcpy(mgmt->da, ra, ETH_ALEN);
 265         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 266         /* BSSID == SA */
 267         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 268         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 269         mgmt->u.action.u.mesh_action.action_code =
 270                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 271         ie_len = 15;
 272         pos = skb_put(skb, 2 + ie_len);
 273         *pos++ = WLAN_EID_PERR;
 274         *pos++ = ie_len;
 275         /* ttl */
 276         *pos++ = ttl;
 277         /* number of destinations */
 278         *pos++ = 1;
 279         /*
 280          * flags bit, bit 1 is unset if we know the sequence number and
 281          * bit 2 is set if we have a reason code
 282          */
 283         *pos = 0;
 284         if (!target_sn)
 285                 *pos |= MP_F_USN;
 286         if (target_rcode)
 287                 *pos |= MP_F_RCODE;
 288         pos++;
 289         memcpy(pos, target, ETH_ALEN);
 290         pos += ETH_ALEN;
 291         memcpy(pos, &target_sn, 4);
 292         pos += 4;
 293         memcpy(pos, &target_rcode, 2);
 294
 295         /* see note in function header */
 296         prepare_frame_for_deferred_tx(sdata, skb);
 297         ifmsh->next_perr = TU_TO_EXP_TIME(
 298                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 299         ieee80211_add_pending_skb(local, skb);
 300         return 0;
 301 }
 302
 303 void ieee80211s_update_metric(struct ieee80211_local *local,
 304                 struct sta_info *stainfo, struct sk_buff *skb)
 305 {
 306         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 307         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 308         int failed;
 309
 310         if (!ieee80211_is_data(hdr->frame_control))
 311                 return;
 312
 313         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 314
 315         /* moving average, scaled to 100 */
 316         stainfo->fail_avg = ((80 * stainfo->fail_avg + 5) / 100 + 20 * failed);
 317         if (stainfo->fail_avg > 95)
 318                 mesh_plink_broken(stainfo);
 319 }
 320
 321 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 322                                    struct sta_info *sta)
 323 {
 324         struct ieee80211_supported_band *sband;
 325         /* This should be adjusted for each device */
 326         int device_constant = 1 << ARITH_SHIFT;
 327         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 328         int s_unit = 1 << ARITH_SHIFT;
 329         int rate, err;
 330         u32 tx_time, estimated_retx;
 331         u64 result;
 332
 333         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 334
 335         if (sta->fail_avg >= 100)
 336                 return MAX_METRIC;
 337
 338         if (sta->last_tx_rate.flags & IEEE80211_TX_RC_MCS)
 339                 return MAX_METRIC;
 340
 341         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 342
 343         /* bitrate is in units of 100 Kbps, while we need rate in units of
 344          * 1Mbps. This will be corrected on tx_time computation.
 345          */
 346         rate = sband->bitrates[sta->last_tx_rate.idx].bitrate;
 347         tx_time = (device_constant + 10 * test_frame_len / rate);
 348         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 349         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 350         return (u32)result;
 351 }
 352
 353 /**
 354  * hwmp_route_info_get - Update routing info to originator and transmitter
 355  *
 356  * @sdata: local mesh subif
 357  * @mgmt: mesh management frame
 358  * @hwmp_ie: hwmp information element (PREP or PREQ)
 359  *
 360  * This function updates the path routing information to the originator and the
 361  * transmitter of a HWMP PREQ or PREP frame.
 362  *
 363  * Returns: metric to frame originator or 0 if the frame should not be further
 364  * processed
 365  *
 366  * Notes: this function is the only place (besides user-provided info) where
 367  * path routing information is updated.
 368  */
 369 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 370                             struct ieee80211_mgmt *mgmt,
 371                             u8 *hwmp_ie, enum mpath_frame_type action)
 372 {
 373         struct ieee80211_local *local = sdata->local;
 374         struct mesh_path *mpath;
 375         struct sta_info *sta;
 376         bool fresh_info;
 377         u8 *orig_addr, *ta;
 378         u32 orig_sn, orig_metric;
 379         unsigned long orig_lifetime, exp_time;
 380         u32 last_hop_metric, new_metric;
 381         bool process = true;
 382
 383         rcu_read_lock();
 384         sta = sta_info_get(sdata, mgmt->sa);
 385         if (!sta) {
 386                 rcu_read_unlock();
 387                 return 0;
 388         }
 389
 390         last_hop_metric = airtime_link_metric_get(local, sta);
 391         /* Update and check originator routing info */
 392         fresh_info = true;
 393
 394         switch (action) {
 395         case MPATH_PREQ:
 396                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 397                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 398                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 399                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 400                 break;
 401         case MPATH_PREP:
 402                 /* Originator here refers to the MP that was the target in the
 403                  * Path Request. We divert from the nomenclature in the draft
 404                  * so that we can easily use a single function to gather path
 405                  * information from both PREQ and PREP frames.
 406                  */
 407                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 408                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 409                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 410                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 411                 break;
 412         default:
 413                 rcu_read_unlock();
 414                 return 0;
 415         }
 416         new_metric = orig_metric + last_hop_metric;
 417         if (new_metric < orig_metric)
 418                 new_metric = MAX_METRIC;
 419         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 420
 421         if (memcmp(orig_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 422                 /* This MP is the originator, we are not interested in this
 423                  * frame, except for updating transmitter's path info.
 424                  */
 425                 process = false;
 426                 fresh_info = false;
 427         } else {
 428                 mpath = mesh_path_lookup(orig_addr, sdata);
 429                 if (mpath) {
 430                         spin_lock_bh(&mpath->state_lock);
 431                         if (mpath->flags & MESH_PATH_FIXED)
 432                                 fresh_info = false;
 433                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 434                             (mpath->flags & MESH_PATH_SN_VALID)) {
 435                                 if (SN_GT(mpath->sn, orig_sn) ||
 436                                     (mpath->sn == orig_sn &&
 437                                      new_metric >= mpath->metric)) {
 438                                         process = false;
 439                                         fresh_info = false;
 440                                 }
 441                         }
 442                 } else {
 443                         mesh_path_add(orig_addr, sdata);
 444                         mpath = mesh_path_lookup(orig_addr, sdata);
 445                         if (!mpath) {
 446                                 rcu_read_unlock();
 447                                 return 0;
 448                         }
 449                         spin_lock_bh(&mpath->state_lock);
 450                 }
 451
 452                 if (fresh_info) {
 453                         mesh_path_assign_nexthop(mpath, sta);
 454                         mpath->flags |= MESH_PATH_SN_VALID;
 455                         mpath->metric = new_metric;
 456                         mpath->sn = orig_sn;
 457                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 458                                           ?  mpath->exp_time : exp_time;
 459                         mesh_path_activate(mpath);
 460                         spin_unlock_bh(&mpath->state_lock);
 461                         mesh_path_tx_pending(mpath);
 462                         /* draft says preq_id should be saved to, but there does
 463                          * not seem to be any use for it, skipping by now
 464                          */
 465                 } else
 466                         spin_unlock_bh(&mpath->state_lock);
 467         }
 468
 469         /* Update and check transmitter routing info */
 470         ta = mgmt->sa;
 471         if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
 472                 fresh_info = false;
 473         else {
 474                 fresh_info = true;
 475
 476                 mpath = mesh_path_lookup(ta, sdata);
 477                 if (mpath) {
 478                         spin_lock_bh(&mpath->state_lock);
 479                         if ((mpath->flags & MESH_PATH_FIXED) ||
 480                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 481                                         (last_hop_metric > mpath->metric)))
 482                                 fresh_info = false;
 483                 } else {
 484                         mesh_path_add(ta, sdata);
 485                         mpath = mesh_path_lookup(ta, sdata);
 486                         if (!mpath) {
 487                                 rcu_read_unlock();
 488                                 return 0;
 489                         }
 490                         spin_lock_bh(&mpath->state_lock);
 491                 }
 492
 493                 if (fresh_info) {
 494                         mesh_path_assign_nexthop(mpath, sta);
 495                         mpath->metric = last_hop_metric;
 496                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 497                                           ?  mpath->exp_time : exp_time;
 498                         mesh_path_activate(mpath);
 499                         spin_unlock_bh(&mpath->state_lock);
 500                         mesh_path_tx_pending(mpath);
 501                 } else
 502                         spin_unlock_bh(&mpath->state_lock);
 503         }
 504
 505         rcu_read_unlock();
 506
 507         return process ? new_metric : 0;
 508 }
 509
 510 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 511                                     struct ieee80211_mgmt *mgmt,
 512                                     u8 *preq_elem, u32 metric)
 513 {
 514         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 515         struct mesh_path *mpath;
 516         u8 *target_addr, *orig_addr;
 517         u8 target_flags, ttl;
 518         u32 orig_sn, target_sn, lifetime;
 519         bool reply = false;
 520         bool forward = true;
 521
 522         /* Update target SN, if present */
 523         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 524         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 525         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 526         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 527         target_flags = PREQ_IE_TARGET_F(preq_elem);
 528
 529         mhwmp_dbg("received PREQ from %pM", orig_addr);
 530
 531         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 532                 mhwmp_dbg("PREQ is for us");
 533                 forward = false;
 534                 reply = true;
 535                 metric = 0;
 536                 if (time_after(jiffies, ifmsh->last_sn_update +
 537                                         net_traversal_jiffies(sdata)) ||
 538                     time_before(jiffies, ifmsh->last_sn_update)) {
 539                         target_sn = ++ifmsh->sn;
 540                         ifmsh->last_sn_update = jiffies;
 541                 }
 542         } else {
 543                 rcu_read_lock();
 544                 mpath = mesh_path_lookup(target_addr, sdata);
 545                 if (mpath) {
 546                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 547                                         SN_LT(mpath->sn, target_sn)) {
 548                                 mpath->sn = target_sn;
 549                                 mpath->flags |= MESH_PATH_SN_VALID;
 550                         } else if ((!(target_flags & MP_F_DO)) &&
 551                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 552                                 reply = true;
 553                                 metric = mpath->metric;
 554                                 target_sn = mpath->sn;
 555                                 if (target_flags & MP_F_RF)
 556                                         target_flags |= MP_F_DO;
 557                                 else
 558                                         forward = false;
 559                         }
 560                 }
 561                 rcu_read_unlock();
 562         }
 563
 564         if (reply) {
 565                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 566                 ttl = ifmsh->mshcfg.element_ttl;
 567                 if (ttl != 0) {
 568                         mhwmp_dbg("replying to the PREQ");
 569                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 570                                 cpu_to_le32(orig_sn), 0, target_addr,
 571                                 cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 572                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 573                                 0, sdata);
 574                 } else
 575                         ifmsh->mshstats.dropped_frames_ttl++;
 576         }
 577
 578         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 579                 u32 preq_id;
 580                 u8 hopcount, flags;
 581
 582                 ttl = PREQ_IE_TTL(preq_elem);
 583                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 584                 if (ttl <= 1) {
 585                         ifmsh->mshstats.dropped_frames_ttl++;
 586                         return;
 587                 }
 588                 mhwmp_dbg("forwarding the PREQ from %pM", orig_addr);
 589                 --ttl;
 590                 flags = PREQ_IE_FLAGS(preq_elem);
 591                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 592                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 593                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 594                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 595                                 cpu_to_le32(target_sn), broadcast_addr,
 596                                 hopcount, ttl, cpu_to_le32(lifetime),
 597                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 598                                 sdata);
 599                 ifmsh->mshstats.fwded_mcast++;
 600                 ifmsh->mshstats.fwded_frames++;
 601         }
 602 }
 603
 604
 605 static inline struct sta_info *
 606 next_hop_deref_protected(struct mesh_path *mpath)
 607 {
 608         return rcu_dereference_protected(mpath->next_hop,
 609                                          lockdep_is_held(&mpath->state_lock));
 610 }
 611
 612
 613 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 614                                     struct ieee80211_mgmt *mgmt,
 615                                     u8 *prep_elem, u32 metric)
 616 {
 617         struct mesh_path *mpath;
 618         u8 *target_addr, *orig_addr;
 619         u8 ttl, hopcount, flags;
 620         u8 next_hop[ETH_ALEN];
 621         u32 target_sn, orig_sn, lifetime;
 622
 623         mhwmp_dbg("received PREP from %pM", PREP_IE_ORIG_ADDR(prep_elem));
 624
 625         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 626         if (memcmp(orig_addr, sdata->vif.addr, ETH_ALEN) == 0)
 627                 /* destination, no forwarding required */
 628                 return;
 629
 630         ttl = PREP_IE_TTL(prep_elem);
 631         if (ttl <= 1) {
 632                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 633                 return;
 634         }
 635
 636         rcu_read_lock();
 637         mpath = mesh_path_lookup(orig_addr, sdata);
 638         if (mpath)
 639                 spin_lock_bh(&mpath->state_lock);
 640         else
 641                 goto fail;
 642         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 643                 spin_unlock_bh(&mpath->state_lock);
 644                 goto fail;
 645         }
 646         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 647         spin_unlock_bh(&mpath->state_lock);
 648         --ttl;
 649         flags = PREP_IE_FLAGS(prep_elem);
 650         lifetime = PREP_IE_LIFETIME(prep_elem);
 651         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 652         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 653         target_sn = PREP_IE_TARGET_SN(prep_elem);
 654         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 655
 656         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 657                 cpu_to_le32(orig_sn), 0, target_addr,
 658                 cpu_to_le32(target_sn), next_hop, hopcount,
 659                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 660                 0, sdata);
 661         rcu_read_unlock();
 662
 663         sdata->u.mesh.mshstats.fwded_unicast++;
 664         sdata->u.mesh.mshstats.fwded_frames++;
 665         return;
 666
 667 fail:
 668         rcu_read_unlock();
 669         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 670 }
 671
 672 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 673                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 674 {
 675         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 676         struct mesh_path *mpath;
 677         u8 ttl;
 678         u8 *ta, *target_addr;
 679         u32 target_sn;
 680         u16 target_rcode;
 681
 682         ta = mgmt->sa;
 683         ttl = PERR_IE_TTL(perr_elem);
 684         if (ttl <= 1) {
 685                 ifmsh->mshstats.dropped_frames_ttl++;
 686                 return;
 687         }
 688         ttl--;
 689         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 690         target_sn = PERR_IE_TARGET_SN(perr_elem);
 691         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 692
 693         rcu_read_lock();
 694         mpath = mesh_path_lookup(target_addr, sdata);
 695         if (mpath) {
 696                 spin_lock_bh(&mpath->state_lock);
 697                 if (mpath->flags & MESH_PATH_ACTIVE &&
 698                     memcmp(ta, next_hop_deref_protected(mpath)->sta.addr,
 699                                                         ETH_ALEN) == 0 &&
 700                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 701                     SN_GT(target_sn, mpath->sn))) {
 702                         mpath->flags &= ~MESH_PATH_ACTIVE;
 703                         mpath->sn = target_sn;
 704                         spin_unlock_bh(&mpath->state_lock);
 705                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 706                                            cpu_to_le16(target_rcode),
 707                                            broadcast_addr, sdata);
 708                 } else
 709                         spin_unlock_bh(&mpath->state_lock);
 710         }
 711         rcu_read_unlock();
 712 }
 713
 714 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 715                                 struct ieee80211_mgmt *mgmt,
 716                                 struct ieee80211_rann_ie *rann)
 717 {
 718         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 719         struct mesh_path *mpath;
 720         u8 ttl, flags, hopcount;
 721         u8 *orig_addr;
 722         u32 orig_sn, metric;
 723         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
 724         bool root_is_gate;
 725
 726         ttl = rann->rann_ttl;
 727         if (ttl <= 1) {
 728                 ifmsh->mshstats.dropped_frames_ttl++;
 729                 return;
 730         }
 731         ttl--;
 732         flags = rann->rann_flags;
 733         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 734         orig_addr = rann->rann_addr;
 735         orig_sn = rann->rann_seq;
 736         hopcount = rann->rann_hopcount;
 737         hopcount++;
 738         metric = rann->rann_metric;
 739
 740         /*  Ignore our own RANNs */
 741         if (memcmp(orig_addr, sdata->vif.addr, ETH_ALEN) == 0)
 742                 return;
 743
 744         mhwmp_dbg("received RANN from %pM (is_gate=%d)", orig_addr,
 745                         root_is_gate);
 746
 747         rcu_read_lock();
 748         mpath = mesh_path_lookup(orig_addr, sdata);
 749         if (!mpath) {
 750                 mesh_path_add(orig_addr, sdata);
 751                 mpath = mesh_path_lookup(orig_addr, sdata);
 752                 if (!mpath) {
 753                         rcu_read_unlock();
 754                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 755                         return;
 756                 }
 757         }
 758
 759         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 760              time_after(jiffies, mpath->exp_time - 1*HZ)) &&
 761              !(mpath->flags & MESH_PATH_FIXED)) {
 762                 mhwmp_dbg("%s time to refresh root mpath %pM", sdata->name,
 763                                                                orig_addr);
 764                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 765         }
 766
 767         if (mpath->sn < orig_sn) {
 768                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 769                                        cpu_to_le32(orig_sn),
 770                                        0, NULL, 0, broadcast_addr,
 771                                        hopcount, ttl, cpu_to_le32(interval),
 772                                        cpu_to_le32(metric + mpath->metric),
 773                                        0, sdata);
 774                 mpath->sn = orig_sn;
 775         }
 776         if (root_is_gate)
 777                 mesh_path_add_gate(mpath);
 778
 779         rcu_read_unlock();
 780 }
 781
 782
 783 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 784                             struct ieee80211_mgmt *mgmt,
 785                             size_t len)
 786 {
 787         struct ieee802_11_elems elems;
 788         size_t baselen;
 789         u32 last_hop_metric;
 790         struct sta_info *sta;
 791
 792         /* need action_code */
 793         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 794                 return;
 795
 796         rcu_read_lock();
 797         sta = sta_info_get(sdata, mgmt->sa);
 798         if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 799                 rcu_read_unlock();
 800                 return;
 801         }
 802         rcu_read_unlock();
 803
 804         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 805         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 806                         len - baselen, &elems);
 807
 808         if (elems.preq) {
 809                 if (elems.preq_len != 37)
 810                         /* Right now we support just 1 destination and no AE */
 811                         return;
 812                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 813                                                       MPATH_PREQ);
 814                 if (last_hop_metric)
 815                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 816                                                 last_hop_metric);
 817         }
 818         if (elems.prep) {
 819                 if (elems.prep_len != 31)
 820                         /* Right now we support no AE */
 821                         return;
 822                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 823                                                       MPATH_PREP);
 824                 if (last_hop_metric)
 825                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 826                                                 last_hop_metric);
 827         }
 828         if (elems.perr) {
 829                 if (elems.perr_len != 15)
 830                         /* Right now we support only one destination per PERR */
 831                         return;
 832                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 833         }
 834         if (elems.rann)
 835                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 836 }
 837
 838 /**
 839  * mesh_queue_preq - queue a PREQ to a given destination
 840  *
 841  * @mpath: mesh path to discover
 842  * @flags: special attributes of the PREQ to be sent
 843  *
 844  * Locking: the function must be called from within a rcu read lock block.
 845  *
 846  */
 847 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 848 {
 849         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 850         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 851         struct mesh_preq_queue *preq_node;
 852
 853         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 854         if (!preq_node) {
 855                 mhwmp_dbg("could not allocate PREQ node");
 856                 return;
 857         }
 858
 859         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 860         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 861                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 862                 kfree(preq_node);
 863                 if (printk_ratelimit())
 864                         mhwmp_dbg("PREQ node queue full");
 865                 return;
 866         }
 867
 868         spin_lock(&mpath->state_lock);
 869         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 870                 spin_unlock(&mpath->state_lock);
 871                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 872                 kfree(preq_node);
 873                 return;
 874         }
 875
 876         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 877         preq_node->flags = flags;
 878
 879         mpath->flags |= MESH_PATH_REQ_QUEUED;
 880         spin_unlock(&mpath->state_lock);
 881
 882         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 883         ++ifmsh->preq_queue_len;
 884         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 885
 886         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 887                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 888
 889         else if (time_before(jiffies, ifmsh->last_preq)) {
 890                 /* avoid long wait if did not send preqs for a long time
 891                  * and jiffies wrapped around
 892                  */
 893                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 894                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 895         } else
 896                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 897                                                 min_preq_int_jiff(sdata));
 898 }
 899
 900 /**
 901  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 902  *
 903  * @sdata: local mesh subif
 904  */
 905 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 906 {
 907         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 908         struct mesh_preq_queue *preq_node;
 909         struct mesh_path *mpath;
 910         u8 ttl, target_flags;
 911         u32 lifetime;
 912
 913         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 914         if (!ifmsh->preq_queue_len ||
 915                 time_before(jiffies, ifmsh->last_preq +
 916                                 min_preq_int_jiff(sdata))) {
 917                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 918                 return;
 919         }
 920
 921         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 922                         struct mesh_preq_queue, list);
 923         list_del(&preq_node->list);
 924         --ifmsh->preq_queue_len;
 925         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 926
 927         rcu_read_lock();
 928         mpath = mesh_path_lookup(preq_node->dst, sdata);
 929         if (!mpath)
 930                 goto enddiscovery;
 931
 932         spin_lock_bh(&mpath->state_lock);
 933         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
 934         if (preq_node->flags & PREQ_Q_F_START) {
 935                 if (mpath->flags & MESH_PATH_RESOLVING) {
 936                         spin_unlock_bh(&mpath->state_lock);
 937                         goto enddiscovery;
 938                 } else {
 939                         mpath->flags &= ~MESH_PATH_RESOLVED;
 940                         mpath->flags |= MESH_PATH_RESOLVING;
 941                         mpath->discovery_retries = 0;
 942                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 943                 }
 944         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 945                         mpath->flags & MESH_PATH_RESOLVED) {
 946                 mpath->flags &= ~MESH_PATH_RESOLVING;
 947                 spin_unlock_bh(&mpath->state_lock);
 948                 goto enddiscovery;
 949         }
 950
 951         ifmsh->last_preq = jiffies;
 952
 953         if (time_after(jiffies, ifmsh->last_sn_update +
 954                                 net_traversal_jiffies(sdata)) ||
 955             time_before(jiffies, ifmsh->last_sn_update)) {
 956                 ++ifmsh->sn;
 957                 sdata->u.mesh.last_sn_update = jiffies;
 958         }
 959         lifetime = default_lifetime(sdata);
 960         ttl = sdata->u.mesh.mshcfg.element_ttl;
 961         if (ttl == 0) {
 962                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 963                 spin_unlock_bh(&mpath->state_lock);
 964                 goto enddiscovery;
 965         }
 966
 967         if (preq_node->flags & PREQ_Q_F_REFRESH)
 968                 target_flags = MP_F_DO;
 969         else
 970                 target_flags = MP_F_RF;
 971
 972         spin_unlock_bh(&mpath->state_lock);
 973         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
 974                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
 975                         cpu_to_le32(mpath->sn), broadcast_addr, 0,
 976                         ttl, cpu_to_le32(lifetime), 0,
 977                         cpu_to_le32(ifmsh->preq_id++), sdata);
 978         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 979
 980 enddiscovery:
 981         rcu_read_unlock();
 982         kfree(preq_node);
 983 }
 984
 985 /* mesh_nexthop_resolve - lookup next hop for given skb and start path
 986  * discovery if no forwarding information is found.
 987  *
 988  * @skb: 802.11 frame to be sent
 989  * @sdata: network subif the frame will be sent through
 990  *
 991  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
 992  * skb is freeed here if no mpath could be allocated.
 993  */
 994 int mesh_nexthop_resolve(struct sk_buff *skb,
 995                          struct ieee80211_sub_if_data *sdata)
 996 {
 997         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 998         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 999         struct mesh_path *mpath;
1000         struct sk_buff *skb_to_free = NULL;
1001         u8 *target_addr = hdr->addr3;
1002         int err = 0;
1003
1004         rcu_read_lock();
1005         err = mesh_nexthop_lookup(skb, sdata);
1006         if (!err)
1007                 goto endlookup;
1008
1009         /* no nexthop found, start resolving */
1010         mpath = mesh_path_lookup(target_addr, sdata);
1011         if (!mpath) {
1012                 mesh_path_add(target_addr, sdata);
1013                 mpath = mesh_path_lookup(target_addr, sdata);
1014                 if (!mpath) {
1015                         mesh_path_discard_frame(skb, sdata);
1016                         err = -ENOSPC;
1017                         goto endlookup;
1018                 }
1019         }
1020
1021         if (!(mpath->flags & MESH_PATH_RESOLVING))
1022                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1023
1024         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1025                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1026
1027         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1028         ieee80211_set_qos_hdr(sdata, skb);
1029         skb_queue_tail(&mpath->frame_queue, skb);
1030         err = -ENOENT;
1031         if (skb_to_free)
1032                 mesh_path_discard_frame(skb_to_free, sdata);
1033
1034 endlookup:
1035         rcu_read_unlock();
1036         return err;
1037 }
1038 /**
1039  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1040  * this function is considered "using" the associated mpath, so preempt a path
1041  * refresh if this mpath expires soon.
1042  *
1043  * @skb: 802.11 frame to be sent
1044  * @sdata: network subif the frame will be sent through
1045  *
1046  * Returns: 0 if the next hop was found. Nonzero otherwise.
1047  */
1048 int mesh_nexthop_lookup(struct sk_buff *skb,
1049                         struct ieee80211_sub_if_data *sdata)
1050 {
1051         struct mesh_path *mpath;
1052         struct sta_info *next_hop;
1053         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1054         u8 *target_addr = hdr->addr3;
1055         int err = -ENOENT;
1056
1057         rcu_read_lock();
1058         mpath = mesh_path_lookup(target_addr, sdata);
1059
1060         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1061                 goto endlookup;
1062
1063         if (time_after(jiffies,
1064                        mpath->exp_time -
1065                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1066             !memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
1067             !(mpath->flags & MESH_PATH_RESOLVING) &&
1068             !(mpath->flags & MESH_PATH_FIXED))
1069                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1070
1071         next_hop = rcu_dereference(mpath->next_hop);
1072         if (next_hop) {
1073                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1074                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1075                 err = 0;
1076         }
1077
1078 endlookup:
1079         rcu_read_unlock();
1080         return err;
1081 }
1082
1083 void mesh_path_timer(unsigned long data)
1084 {
1085         struct mesh_path *mpath = (void *) data;
1086         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1087         int ret;
1088
1089         if (sdata->local->quiescing)
1090                 return;
1091
1092         spin_lock_bh(&mpath->state_lock);
1093         if (mpath->flags & MESH_PATH_RESOLVED ||
1094                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1095                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1096                 spin_unlock_bh(&mpath->state_lock);
1097         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1098                 ++mpath->discovery_retries;
1099                 mpath->discovery_timeout *= 2;
1100                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1101                 spin_unlock_bh(&mpath->state_lock);
1102                 mesh_queue_preq(mpath, 0);
1103         } else {
1104                 mpath->flags = 0;
1105                 mpath->exp_time = jiffies;
1106                 spin_unlock_bh(&mpath->state_lock);
1107                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1108                         ret = mesh_path_send_to_gates(mpath);
1109                         if (ret)
1110                                 mhwmp_dbg("no gate was reachable");
1111                 } else
1112                         mesh_path_flush_pending(mpath);
1113         }
1114 }
1115
1116 void
1117 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1118 {
1119         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1120         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1121         u8 flags;
1122
1123         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1124                         ? RANN_FLAG_IS_GATE : 0;
1125         mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1126                                cpu_to_le32(++ifmsh->sn),
1127                                0, NULL, 0, broadcast_addr,
1128                                0, sdata->u.mesh.mshcfg.element_ttl,
1129                                cpu_to_le32(interval), 0, 0, sdata);
1130 }