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 <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 #define LINK_FAIL_THRESH 95
  20
  21 #define MAX_PREQ_QUEUE_LEN      64
  22
  23 static void mesh_queue_preq(struct mesh_path *, u8);
  24
  25 static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
  26 {
  27         if (ae)
  28                 offset += 6;
  29         return get_unaligned_le32(preq_elem + offset);
  30 }
  31
  32 static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
  33 {
  34         if (ae)
  35                 offset += 6;
  36         return get_unaligned_le16(preq_elem + offset);
  37 }
  38
  39 /* HWMP IE processing macros */
  40 #define AE_F                    (1<<6)
  41 #define AE_F_SET(x)             (*x & AE_F)
  42 #define PREQ_IE_FLAGS(x)        (*(x))
  43 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  44 #define PREQ_IE_TTL(x)          (*(x + 2))
  45 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  46 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  47 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  48 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  49 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  50 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  51 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  52 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  53
  54
  55 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  56 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  57 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  58 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  59 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  60 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  61 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  62 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  63 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  64
  65 #define PERR_IE_TTL(x)          (*(x))
  66 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  67 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  68 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  69 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  70
  71 #define MSEC_TO_TU(x) (x*1000/1024)
  72 #define SN_GT(x, y) ((s32)(y - x) < 0)
  73 #define SN_LT(x, y) ((s32)(x - y) < 0)
  74 #define MAX_SANE_SN_DELTA 32
  75
  76 static inline u32 SN_DELTA(u32 x, u32 y)
  77 {
  78         return x >= y ? x - y : y - x;
  79 }
  80
  81 #define net_traversal_jiffies(s) \
  82         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  83 #define default_lifetime(s) \
  84         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  85 #define min_preq_int_jiff(s) \
  86         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  87 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  88 #define disc_timeout_jiff(s) \
  89         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  90 #define root_path_confirmation_jiffies(s) \
  91         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  92
  93 enum mpath_frame_type {
  94         MPATH_PREQ = 0,
  95         MPATH_PREP,
  96         MPATH_PERR,
  97         MPATH_RANN
  98 };
  99
 100 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 101
 102 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 103                                   const u8 *orig_addr, u32 orig_sn,
 104                                   u8 target_flags, const u8 *target,
 105                                   u32 target_sn, const u8 *da,
 106                                   u8 hop_count, u8 ttl,
 107                                   u32 lifetime, u32 metric, u32 preq_id,
 108                                   struct ieee80211_sub_if_data *sdata)
 109 {
 110         struct ieee80211_local *local = sdata->local;
 111         struct sk_buff *skb;
 112         struct ieee80211_mgmt *mgmt;
 113         u8 *pos, ie_len;
 114         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 115                       sizeof(mgmt->u.action.u.mesh_action);
 116
 117         skb = dev_alloc_skb(local->tx_headroom +
 118                             hdr_len +
 119                             2 + 37); /* max HWMP IE */
 120         if (!skb)
 121                 return -1;
 122         skb_reserve(skb, local->tx_headroom);
 123         mgmt = skb_put_zero(skb, hdr_len);
 124         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 125                                           IEEE80211_STYPE_ACTION);
 126
 127         memcpy(mgmt->da, da, ETH_ALEN);
 128         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 129         /* BSSID == SA */
 130         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 131         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 132         mgmt->u.action.u.mesh_action.action_code =
 133                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 134
 135         switch (action) {
 136         case MPATH_PREQ:
 137                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 138                 ie_len = 37;
 139                 pos = skb_put(skb, 2 + ie_len);
 140                 *pos++ = WLAN_EID_PREQ;
 141                 break;
 142         case MPATH_PREP:
 143                 mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
 144                 ie_len = 31;
 145                 pos = skb_put(skb, 2 + ie_len);
 146                 *pos++ = WLAN_EID_PREP;
 147                 break;
 148         case MPATH_RANN:
 149                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 150                 ie_len = sizeof(struct ieee80211_rann_ie);
 151                 pos = skb_put(skb, 2 + ie_len);
 152                 *pos++ = WLAN_EID_RANN;
 153                 break;
 154         default:
 155                 kfree_skb(skb);
 156                 return -ENOTSUPP;
 157         }
 158         *pos++ = ie_len;
 159         *pos++ = flags;
 160         *pos++ = hop_count;
 161         *pos++ = ttl;
 162         if (action == MPATH_PREP) {
 163                 memcpy(pos, target, ETH_ALEN);
 164                 pos += ETH_ALEN;
 165                 put_unaligned_le32(target_sn, pos);
 166                 pos += 4;
 167         } else {
 168                 if (action == MPATH_PREQ) {
 169                         put_unaligned_le32(preq_id, pos);
 170                         pos += 4;
 171                 }
 172                 memcpy(pos, orig_addr, ETH_ALEN);
 173                 pos += ETH_ALEN;
 174                 put_unaligned_le32(orig_sn, pos);
 175                 pos += 4;
 176         }
 177         put_unaligned_le32(lifetime, pos); /* interval for RANN */
 178         pos += 4;
 179         put_unaligned_le32(metric, pos);
 180         pos += 4;
 181         if (action == MPATH_PREQ) {
 182                 *pos++ = 1; /* destination count */
 183                 *pos++ = target_flags;
 184                 memcpy(pos, target, ETH_ALEN);
 185                 pos += ETH_ALEN;
 186                 put_unaligned_le32(target_sn, pos);
 187                 pos += 4;
 188         } else if (action == MPATH_PREP) {
 189                 memcpy(pos, orig_addr, ETH_ALEN);
 190                 pos += ETH_ALEN;
 191                 put_unaligned_le32(orig_sn, pos);
 192                 pos += 4;
 193         }
 194
 195         ieee80211_tx_skb(sdata, skb);
 196         return 0;
 197 }
 198
 199
 200 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 201  *  headroom in case the frame is encrypted. */
 202 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 203                 struct sk_buff *skb)
 204 {
 205         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 206         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 207
 208         skb_reset_mac_header(skb);
 209         skb_reset_network_header(skb);
 210         skb_reset_transport_header(skb);
 211
 212         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 213         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 214         skb->priority = 7;
 215
 216         info->control.vif = &sdata->vif;
 217         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 218         ieee80211_set_qos_hdr(sdata, skb);
 219         ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
 220 }
 221
 222 /**
 223  * mesh_path_error_tx - Sends a PERR mesh management frame
 224  *
 225  * @ttl: allowed remaining hops
 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  * @sdata: local mesh subif
 231  *
 232  * Note: This function may be called with driver locks taken that the driver
 233  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 234  * frame directly but add it to the pending queue instead.
 235  */
 236 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 237                        u8 ttl, const u8 *target, u32 target_sn,
 238                        u16 target_rcode, const u8 *ra)
 239 {
 240         struct ieee80211_local *local = sdata->local;
 241         struct sk_buff *skb;
 242         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 243         struct ieee80211_mgmt *mgmt;
 244         u8 *pos, ie_len;
 245         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 246                       sizeof(mgmt->u.action.u.mesh_action);
 247
 248         if (time_before(jiffies, ifmsh->next_perr))
 249                 return -EAGAIN;
 250
 251         skb = dev_alloc_skb(local->tx_headroom +
 252                             sdata->encrypt_headroom +
 253                             IEEE80211_ENCRYPT_TAILROOM +
 254                             hdr_len +
 255                             2 + 15 /* PERR IE */);
 256         if (!skb)
 257                 return -1;
 258         skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom);
 259         mgmt = skb_put_zero(skb, hdr_len);
 260         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 261                                           IEEE80211_STYPE_ACTION);
 262
 263         memcpy(mgmt->da, ra, ETH_ALEN);
 264         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 265         /* BSSID == SA */
 266         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 267         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 268         mgmt->u.action.u.mesh_action.action_code =
 269                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 270         ie_len = 15;
 271         pos = skb_put(skb, 2 + ie_len);
 272         *pos++ = WLAN_EID_PERR;
 273         *pos++ = ie_len;
 274         /* ttl */
 275         *pos++ = ttl;
 276         /* number of destinations */
 277         *pos++ = 1;
 278         /* Flags field has AE bit only as defined in
 279          * sec 8.4.2.117 IEEE802.11-2012
 280          */
 281         *pos = 0;
 282         pos++;
 283         memcpy(pos, target, ETH_ALEN);
 284         pos += ETH_ALEN;
 285         put_unaligned_le32(target_sn, pos);
 286         pos += 4;
 287         put_unaligned_le16(target_rcode, pos);
 288
 289         /* see note in function header */
 290         prepare_frame_for_deferred_tx(sdata, skb);
 291         ifmsh->next_perr = TU_TO_EXP_TIME(
 292                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 293         ieee80211_add_pending_skb(local, skb);
 294         return 0;
 295 }
 296
 297 void ieee80211s_update_metric(struct ieee80211_local *local,
 298                               struct sta_info *sta,
 299                               struct ieee80211_tx_status *st)
 300 {
 301         struct ieee80211_tx_info *txinfo = st->info;
 302         int failed;
 303
 304         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 305
 306         /* moving average, scaled to 100.
 307          * feed failure as 100 and success as 0
 308          */
 309         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
 310         if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
 311                         LINK_FAIL_THRESH)
 312                 mesh_plink_broken(sta);
 313 }
 314
 315 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 316                                    struct sta_info *sta)
 317 {
 318         struct rate_info rinfo;
 319         /* This should be adjusted for each device */
 320         int device_constant = 1 << ARITH_SHIFT;
 321         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 322         int s_unit = 1 << ARITH_SHIFT;
 323         int rate, err;
 324         u32 tx_time, estimated_retx;
 325         u64 result;
 326         unsigned long fail_avg =
 327                 ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
 328
 329         if (sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 330                 return MAX_METRIC;
 331
 332         /* Try to get rate based on HW/SW RC algorithm.
 333          * Rate is returned in units of Kbps, correct this
 334          * to comply with airtime calculation units
 335          * Round up in case we get rate < 100Kbps
 336          */
 337         rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
 338
 339         if (rate) {
 340                 err = 0;
 341         } else {
 342                 if (fail_avg > LINK_FAIL_THRESH)
 343                         return MAX_METRIC;
 344
 345                 sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
 346                 rate = cfg80211_calculate_bitrate(&rinfo);
 347                 if (WARN_ON(!rate))
 348                         return MAX_METRIC;
 349
 350                 err = (fail_avg << ARITH_SHIFT) / 100;
 351         }
 352
 353         /* bitrate is in units of 100 Kbps, while we need rate in units of
 354          * 1Mbps. This will be corrected on tx_time computation.
 355          */
 356         tx_time = (device_constant + 10 * test_frame_len / rate);
 357         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 358         result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
 359         return (u32)result;
 360 }
 361
 362 /**
 363  * hwmp_route_info_get - Update routing info to originator and transmitter
 364  *
 365  * @sdata: local mesh subif
 366  * @mgmt: mesh management frame
 367  * @hwmp_ie: hwmp information element (PREP or PREQ)
 368  * @action: type of hwmp ie
 369  *
 370  * This function updates the path routing information to the originator and the
 371  * transmitter of a HWMP PREQ or PREP frame.
 372  *
 373  * Returns: metric to frame originator or 0 if the frame should not be further
 374  * processed
 375  *
 376  * Notes: this function is the only place (besides user-provided info) where
 377  * path routing information is updated.
 378  */
 379 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 380                                struct ieee80211_mgmt *mgmt,
 381                                const u8 *hwmp_ie, enum mpath_frame_type action)
 382 {
 383         struct ieee80211_local *local = sdata->local;
 384         struct mesh_path *mpath;
 385         struct sta_info *sta;
 386         bool fresh_info;
 387         const u8 *orig_addr, *ta;
 388         u32 orig_sn, orig_metric;
 389         unsigned long orig_lifetime, exp_time;
 390         u32 last_hop_metric, new_metric;
 391         bool process = true;
 392
 393         rcu_read_lock();
 394         sta = sta_info_get(sdata, mgmt->sa);
 395         if (!sta) {
 396                 rcu_read_unlock();
 397                 return 0;
 398         }
 399
 400         last_hop_metric = airtime_link_metric_get(local, sta);
 401         /* Update and check originator routing info */
 402         fresh_info = true;
 403
 404         switch (action) {
 405         case MPATH_PREQ:
 406                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 407                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 408                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 409                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 410                 break;
 411         case MPATH_PREP:
 412                 /* Originator here refers to the MP that was the target in the
 413                  * Path Request. We divert from the nomenclature in the draft
 414                  * so that we can easily use a single function to gather path
 415                  * information from both PREQ and PREP frames.
 416                  */
 417                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 418                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 419                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 420                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 421                 break;
 422         default:
 423                 rcu_read_unlock();
 424                 return 0;
 425         }
 426         new_metric = orig_metric + last_hop_metric;
 427         if (new_metric < orig_metric)
 428                 new_metric = MAX_METRIC;
 429         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 430
 431         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 432                 /* This MP is the originator, we are not interested in this
 433                  * frame, except for updating transmitter's path info.
 434                  */
 435                 process = false;
 436                 fresh_info = false;
 437         } else {
 438                 mpath = mesh_path_lookup(sdata, orig_addr);
 439                 if (mpath) {
 440                         spin_lock_bh(&mpath->state_lock);
 441                         if (mpath->flags & MESH_PATH_FIXED)
 442                                 fresh_info = false;
 443                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 444                             (mpath->flags & MESH_PATH_SN_VALID)) {
 445                                 if (SN_GT(mpath->sn, orig_sn) ||
 446                                     (mpath->sn == orig_sn &&
 447                                      new_metric >= mpath->metric)) {
 448                                         process = false;
 449                                         fresh_info = false;
 450                                 }
 451                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 452                                 bool have_sn, newer_sn, bounced;
 453
 454                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 455                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 456                                 bounced = have_sn &&
 457                                           (SN_DELTA(orig_sn, mpath->sn) >
 458                                                         MAX_SANE_SN_DELTA);
 459
 460                                 if (!have_sn || newer_sn) {
 461                                         /* if SN is newer than what we had
 462                                          * then we can take it */;
 463                                 } else if (bounced) {
 464                                         /* if SN is way different than what
 465                                          * we had then assume the other side
 466                                          * rebooted or restarted */;
 467                                 } else {
 468                                         process = false;
 469                                         fresh_info = false;
 470                                 }
 471                         }
 472                 } else {
 473                         mpath = mesh_path_add(sdata, orig_addr);
 474                         if (IS_ERR(mpath)) {
 475                                 rcu_read_unlock();
 476                                 return 0;
 477                         }
 478                         spin_lock_bh(&mpath->state_lock);
 479                 }
 480
 481                 if (fresh_info) {
 482                         mesh_path_assign_nexthop(mpath, sta);
 483                         mpath->flags |= MESH_PATH_SN_VALID;
 484                         mpath->metric = new_metric;
 485                         mpath->sn = orig_sn;
 486                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 487                                           ?  mpath->exp_time : exp_time;
 488                         mesh_path_activate(mpath);
 489                         spin_unlock_bh(&mpath->state_lock);
 490                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 491                         /* init it at a low value - 0 start is tricky */
 492                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 493                         mesh_path_tx_pending(mpath);
 494                         /* draft says preq_id should be saved to, but there does
 495                          * not seem to be any use for it, skipping by now
 496                          */
 497                 } else
 498                         spin_unlock_bh(&mpath->state_lock);
 499         }
 500
 501         /* Update and check transmitter routing info */
 502         ta = mgmt->sa;
 503         if (ether_addr_equal(orig_addr, ta))
 504                 fresh_info = false;
 505         else {
 506                 fresh_info = true;
 507
 508                 mpath = mesh_path_lookup(sdata, ta);
 509                 if (mpath) {
 510                         spin_lock_bh(&mpath->state_lock);
 511                         if ((mpath->flags & MESH_PATH_FIXED) ||
 512                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 513                                         (last_hop_metric > mpath->metric)))
 514                                 fresh_info = false;
 515                 } else {
 516                         mpath = mesh_path_add(sdata, ta);
 517                         if (IS_ERR(mpath)) {
 518                                 rcu_read_unlock();
 519                                 return 0;
 520                         }
 521                         spin_lock_bh(&mpath->state_lock);
 522                 }
 523
 524                 if (fresh_info) {
 525                         mesh_path_assign_nexthop(mpath, sta);
 526                         mpath->metric = last_hop_metric;
 527                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 528                                           ?  mpath->exp_time : exp_time;
 529                         mesh_path_activate(mpath);
 530                         spin_unlock_bh(&mpath->state_lock);
 531                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 532                         /* init it at a low value - 0 start is tricky */
 533                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 534                         mesh_path_tx_pending(mpath);
 535                 } else
 536                         spin_unlock_bh(&mpath->state_lock);
 537         }
 538
 539         rcu_read_unlock();
 540
 541         return process ? new_metric : 0;
 542 }
 543
 544 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 545                                     struct ieee80211_mgmt *mgmt,
 546                                     const u8 *preq_elem, u32 orig_metric)
 547 {
 548         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 549         struct mesh_path *mpath = NULL;
 550         const u8 *target_addr, *orig_addr;
 551         const u8 *da;
 552         u8 target_flags, ttl, flags;
 553         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 554         bool reply = false;
 555         bool forward = true;
 556         bool root_is_gate;
 557
 558         /* Update target SN, if present */
 559         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 560         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 561         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 562         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 563         target_flags = PREQ_IE_TARGET_F(preq_elem);
 564         /* Proactive PREQ gate announcements */
 565         flags = PREQ_IE_FLAGS(preq_elem);
 566         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 567
 568         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 569
 570         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 571                 mhwmp_dbg(sdata, "PREQ is for us\n");
 572                 forward = false;
 573                 reply = true;
 574                 target_metric = 0;
 575
 576                 if (SN_GT(target_sn, ifmsh->sn))
 577                         ifmsh->sn = target_sn;
 578
 579                 if (time_after(jiffies, ifmsh->last_sn_update +
 580                                         net_traversal_jiffies(sdata)) ||
 581                     time_before(jiffies, ifmsh->last_sn_update)) {
 582                         ++ifmsh->sn;
 583                         ifmsh->last_sn_update = jiffies;
 584                 }
 585                 target_sn = ifmsh->sn;
 586         } else if (is_broadcast_ether_addr(target_addr) &&
 587                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 588                 rcu_read_lock();
 589                 mpath = mesh_path_lookup(sdata, orig_addr);
 590                 if (mpath) {
 591                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 592                                 reply = true;
 593                                 target_addr = sdata->vif.addr;
 594                                 target_sn = ++ifmsh->sn;
 595                                 target_metric = 0;
 596                                 ifmsh->last_sn_update = jiffies;
 597                         }
 598                         if (root_is_gate)
 599                                 mesh_path_add_gate(mpath);
 600                 }
 601                 rcu_read_unlock();
 602         } else {
 603                 rcu_read_lock();
 604                 mpath = mesh_path_lookup(sdata, target_addr);
 605                 if (mpath) {
 606                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 607                                         SN_LT(mpath->sn, target_sn)) {
 608                                 mpath->sn = target_sn;
 609                                 mpath->flags |= MESH_PATH_SN_VALID;
 610                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 611                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 612                                 reply = true;
 613                                 target_metric = mpath->metric;
 614                                 target_sn = mpath->sn;
 615                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 616                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 617                         }
 618                 }
 619                 rcu_read_unlock();
 620         }
 621
 622         if (reply) {
 623                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 624                 ttl = ifmsh->mshcfg.element_ttl;
 625                 if (ttl != 0) {
 626                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 627                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 628                                                orig_sn, 0, target_addr,
 629                                                target_sn, mgmt->sa, 0, ttl,
 630                                                lifetime, target_metric, 0,
 631                                                sdata);
 632                 } else {
 633                         ifmsh->mshstats.dropped_frames_ttl++;
 634                 }
 635         }
 636
 637         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 638                 u32 preq_id;
 639                 u8 hopcount;
 640
 641                 ttl = PREQ_IE_TTL(preq_elem);
 642                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 643                 if (ttl <= 1) {
 644                         ifmsh->mshstats.dropped_frames_ttl++;
 645                         return;
 646                 }
 647                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 648                 --ttl;
 649                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 650                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 651                 da = (mpath && mpath->is_root) ?
 652                         mpath->rann_snd_addr : broadcast_addr;
 653
 654                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 655                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 656                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 657                 }
 658
 659                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 660                                        orig_sn, target_flags, target_addr,
 661                                        target_sn, da, hopcount, ttl, lifetime,
 662                                        orig_metric, preq_id, sdata);
 663                 if (!is_multicast_ether_addr(da))
 664                         ifmsh->mshstats.fwded_unicast++;
 665                 else
 666                         ifmsh->mshstats.fwded_mcast++;
 667                 ifmsh->mshstats.fwded_frames++;
 668         }
 669 }
 670
 671
 672 static inline struct sta_info *
 673 next_hop_deref_protected(struct mesh_path *mpath)
 674 {
 675         return rcu_dereference_protected(mpath->next_hop,
 676                                          lockdep_is_held(&mpath->state_lock));
 677 }
 678
 679
 680 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 681                                     struct ieee80211_mgmt *mgmt,
 682                                     const u8 *prep_elem, u32 metric)
 683 {
 684         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 685         struct mesh_path *mpath;
 686         const u8 *target_addr, *orig_addr;
 687         u8 ttl, hopcount, flags;
 688         u8 next_hop[ETH_ALEN];
 689         u32 target_sn, orig_sn, lifetime;
 690
 691         mhwmp_dbg(sdata, "received PREP from %pM\n",
 692                   PREP_IE_TARGET_ADDR(prep_elem));
 693
 694         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 695         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 696                 /* destination, no forwarding required */
 697                 return;
 698
 699         if (!ifmsh->mshcfg.dot11MeshForwarding)
 700                 return;
 701
 702         ttl = PREP_IE_TTL(prep_elem);
 703         if (ttl <= 1) {
 704                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 705                 return;
 706         }
 707
 708         rcu_read_lock();
 709         mpath = mesh_path_lookup(sdata, orig_addr);
 710         if (mpath)
 711                 spin_lock_bh(&mpath->state_lock);
 712         else
 713                 goto fail;
 714         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 715                 spin_unlock_bh(&mpath->state_lock);
 716                 goto fail;
 717         }
 718         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 719         spin_unlock_bh(&mpath->state_lock);
 720         --ttl;
 721         flags = PREP_IE_FLAGS(prep_elem);
 722         lifetime = PREP_IE_LIFETIME(prep_elem);
 723         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 724         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 725         target_sn = PREP_IE_TARGET_SN(prep_elem);
 726         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 727
 728         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 729                                target_addr, target_sn, next_hop, hopcount,
 730                                ttl, lifetime, metric, 0, sdata);
 731         rcu_read_unlock();
 732
 733         sdata->u.mesh.mshstats.fwded_unicast++;
 734         sdata->u.mesh.mshstats.fwded_frames++;
 735         return;
 736
 737 fail:
 738         rcu_read_unlock();
 739         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 740 }
 741
 742 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 743                                     struct ieee80211_mgmt *mgmt,
 744                                     const u8 *perr_elem)
 745 {
 746         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 747         struct mesh_path *mpath;
 748         u8 ttl;
 749         const u8 *ta, *target_addr;
 750         u32 target_sn;
 751         u16 target_rcode;
 752
 753         ta = mgmt->sa;
 754         ttl = PERR_IE_TTL(perr_elem);
 755         if (ttl <= 1) {
 756                 ifmsh->mshstats.dropped_frames_ttl++;
 757                 return;
 758         }
 759         ttl--;
 760         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 761         target_sn = PERR_IE_TARGET_SN(perr_elem);
 762         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 763
 764         rcu_read_lock();
 765         mpath = mesh_path_lookup(sdata, target_addr);
 766         if (mpath) {
 767                 struct sta_info *sta;
 768
 769                 spin_lock_bh(&mpath->state_lock);
 770                 sta = next_hop_deref_protected(mpath);
 771                 if (mpath->flags & MESH_PATH_ACTIVE &&
 772                     ether_addr_equal(ta, sta->sta.addr) &&
 773                     !(mpath->flags & MESH_PATH_FIXED) &&
 774                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 775                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 776                         mpath->flags &= ~MESH_PATH_ACTIVE;
 777                         if (target_sn != 0)
 778                                 mpath->sn = target_sn;
 779                         else
 780                                 mpath->sn += 1;
 781                         spin_unlock_bh(&mpath->state_lock);
 782                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 783                                 goto endperr;
 784                         mesh_path_error_tx(sdata, ttl, target_addr,
 785                                            target_sn, target_rcode,
 786                                            broadcast_addr);
 787                 } else
 788                         spin_unlock_bh(&mpath->state_lock);
 789         }
 790 endperr:
 791         rcu_read_unlock();
 792 }
 793
 794 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 795                                     struct ieee80211_mgmt *mgmt,
 796                                     const struct ieee80211_rann_ie *rann)
 797 {
 798         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 799         struct ieee80211_local *local = sdata->local;
 800         struct sta_info *sta;
 801         struct mesh_path *mpath;
 802         u8 ttl, flags, hopcount;
 803         const u8 *orig_addr;
 804         u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
 805         bool root_is_gate;
 806
 807         ttl = rann->rann_ttl;
 808         flags = rann->rann_flags;
 809         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 810         orig_addr = rann->rann_addr;
 811         orig_sn = le32_to_cpu(rann->rann_seq);
 812         interval = le32_to_cpu(rann->rann_interval);
 813         hopcount = rann->rann_hopcount;
 814         hopcount++;
 815         orig_metric = le32_to_cpu(rann->rann_metric);
 816
 817         /*  Ignore our own RANNs */
 818         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 819                 return;
 820
 821         mhwmp_dbg(sdata,
 822                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 823                   orig_addr, mgmt->sa, root_is_gate);
 824
 825         rcu_read_lock();
 826         sta = sta_info_get(sdata, mgmt->sa);
 827         if (!sta) {
 828                 rcu_read_unlock();
 829                 return;
 830         }
 831
 832         last_hop_metric = airtime_link_metric_get(local, sta);
 833         new_metric = orig_metric + last_hop_metric;
 834         if (new_metric < orig_metric)
 835                 new_metric = MAX_METRIC;
 836
 837         mpath = mesh_path_lookup(sdata, orig_addr);
 838         if (!mpath) {
 839                 mpath = mesh_path_add(sdata, orig_addr);
 840                 if (IS_ERR(mpath)) {
 841                         rcu_read_unlock();
 842                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 843                         return;
 844                 }
 845         }
 846
 847         if (!(SN_LT(mpath->sn, orig_sn)) &&
 848             !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
 849                 rcu_read_unlock();
 850                 return;
 851         }
 852
 853         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 854              (time_after(jiffies, mpath->last_preq_to_root +
 855                                   root_path_confirmation_jiffies(sdata)) ||
 856              time_before(jiffies, mpath->last_preq_to_root))) &&
 857              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 858                 mhwmp_dbg(sdata,
 859                           "time to refresh root mpath %pM\n",
 860                           orig_addr);
 861                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 862                 mpath->last_preq_to_root = jiffies;
 863         }
 864
 865         mpath->sn = orig_sn;
 866         mpath->rann_metric = new_metric;
 867         mpath->is_root = true;
 868         /* Recording RANNs sender address to send individually
 869          * addressed PREQs destined for root mesh STA */
 870         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 871
 872         if (root_is_gate)
 873                 mesh_path_add_gate(mpath);
 874
 875         if (ttl <= 1) {
 876                 ifmsh->mshstats.dropped_frames_ttl++;
 877                 rcu_read_unlock();
 878                 return;
 879         }
 880         ttl--;
 881
 882         if (ifmsh->mshcfg.dot11MeshForwarding) {
 883                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 884                                        orig_sn, 0, NULL, 0, broadcast_addr,
 885                                        hopcount, ttl, interval,
 886                                        new_metric, 0, sdata);
 887         }
 888
 889         rcu_read_unlock();
 890 }
 891
 892
 893 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 894                             struct ieee80211_mgmt *mgmt, size_t len)
 895 {
 896         struct ieee802_11_elems elems;
 897         size_t baselen;
 898         u32 path_metric;
 899         struct sta_info *sta;
 900
 901         /* need action_code */
 902         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 903                 return;
 904
 905         rcu_read_lock();
 906         sta = sta_info_get(sdata, mgmt->sa);
 907         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 908                 rcu_read_unlock();
 909                 return;
 910         }
 911         rcu_read_unlock();
 912
 913         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 914         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 915                                len - baselen, false, &elems);
 916
 917         if (elems.preq) {
 918                 if (elems.preq_len != 37)
 919                         /* Right now we support just 1 destination and no AE */
 920                         return;
 921                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 922                                                   MPATH_PREQ);
 923                 if (path_metric)
 924                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 925                                                 path_metric);
 926         }
 927         if (elems.prep) {
 928                 if (elems.prep_len != 31)
 929                         /* Right now we support no AE */
 930                         return;
 931                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 932                                                   MPATH_PREP);
 933                 if (path_metric)
 934                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 935                                                 path_metric);
 936         }
 937         if (elems.perr) {
 938                 if (elems.perr_len != 15)
 939                         /* Right now we support only one destination per PERR */
 940                         return;
 941                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 942         }
 943         if (elems.rann)
 944                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 945 }
 946
 947 /**
 948  * mesh_queue_preq - queue a PREQ to a given destination
 949  *
 950  * @mpath: mesh path to discover
 951  * @flags: special attributes of the PREQ to be sent
 952  *
 953  * Locking: the function must be called from within a rcu read lock block.
 954  *
 955  */
 956 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 957 {
 958         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 959         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 960         struct mesh_preq_queue *preq_node;
 961
 962         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 963         if (!preq_node) {
 964                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 965                 return;
 966         }
 967
 968         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 969         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 970                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 971                 kfree(preq_node);
 972                 if (printk_ratelimit())
 973                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 974                 return;
 975         }
 976
 977         spin_lock(&mpath->state_lock);
 978         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 979                 spin_unlock(&mpath->state_lock);
 980                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 981                 kfree(preq_node);
 982                 return;
 983         }
 984
 985         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 986         preq_node->flags = flags;
 987
 988         mpath->flags |= MESH_PATH_REQ_QUEUED;
 989         spin_unlock(&mpath->state_lock);
 990
 991         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 992         ++ifmsh->preq_queue_len;
 993         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 994
 995         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 996                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 997
 998         else if (time_before(jiffies, ifmsh->last_preq)) {
 999                 /* avoid long wait if did not send preqs for a long time
1000                  * and jiffies wrapped around
1001                  */
1002                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1003                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1004         } else
1005                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1006                                                 min_preq_int_jiff(sdata));
1007 }
1008
1009 /**
1010  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1011  *
1012  * @sdata: local mesh subif
1013  */
1014 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1015 {
1016         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1017         struct mesh_preq_queue *preq_node;
1018         struct mesh_path *mpath;
1019         u8 ttl, target_flags = 0;
1020         const u8 *da;
1021         u32 lifetime;
1022
1023         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1024         if (!ifmsh->preq_queue_len ||
1025                 time_before(jiffies, ifmsh->last_preq +
1026                                 min_preq_int_jiff(sdata))) {
1027                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1028                 return;
1029         }
1030
1031         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1032                         struct mesh_preq_queue, list);
1033         list_del(&preq_node->list);
1034         --ifmsh->preq_queue_len;
1035         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1036
1037         rcu_read_lock();
1038         mpath = mesh_path_lookup(sdata, preq_node->dst);
1039         if (!mpath)
1040                 goto enddiscovery;
1041
1042         spin_lock_bh(&mpath->state_lock);
1043         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1044                 spin_unlock_bh(&mpath->state_lock);
1045                 goto enddiscovery;
1046         }
1047         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1048         if (preq_node->flags & PREQ_Q_F_START) {
1049                 if (mpath->flags & MESH_PATH_RESOLVING) {
1050                         spin_unlock_bh(&mpath->state_lock);
1051                         goto enddiscovery;
1052                 } else {
1053                         mpath->flags &= ~MESH_PATH_RESOLVED;
1054                         mpath->flags |= MESH_PATH_RESOLVING;
1055                         mpath->discovery_retries = 0;
1056                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1057                 }
1058         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1059                         mpath->flags & MESH_PATH_RESOLVED) {
1060                 mpath->flags &= ~MESH_PATH_RESOLVING;
1061                 spin_unlock_bh(&mpath->state_lock);
1062                 goto enddiscovery;
1063         }
1064
1065         ifmsh->last_preq = jiffies;
1066
1067         if (time_after(jiffies, ifmsh->last_sn_update +
1068                                 net_traversal_jiffies(sdata)) ||
1069             time_before(jiffies, ifmsh->last_sn_update)) {
1070                 ++ifmsh->sn;
1071                 sdata->u.mesh.last_sn_update = jiffies;
1072         }
1073         lifetime = default_lifetime(sdata);
1074         ttl = sdata->u.mesh.mshcfg.element_ttl;
1075         if (ttl == 0) {
1076                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1077                 spin_unlock_bh(&mpath->state_lock);
1078                 goto enddiscovery;
1079         }
1080
1081         if (preq_node->flags & PREQ_Q_F_REFRESH)
1082                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1083         else
1084                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1085
1086         spin_unlock_bh(&mpath->state_lock);
1087         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1088         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1089                                target_flags, mpath->dst, mpath->sn, da, 0,
1090                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1091
1092         spin_lock_bh(&mpath->state_lock);
1093         if (mpath->flags & MESH_PATH_DELETED) {
1094                 spin_unlock_bh(&mpath->state_lock);
1095                 goto enddiscovery;
1096         }
1097         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1098         spin_unlock_bh(&mpath->state_lock);
1099
1100 enddiscovery:
1101         rcu_read_unlock();
1102         kfree(preq_node);
1103 }
1104
1105 /**
1106  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1107  *
1108  * @skb: 802.11 frame to be sent
1109  * @sdata: network subif the frame will be sent through
1110  *
1111  * Lookup next hop for given skb and start path discovery if no
1112  * forwarding information is found.
1113  *
1114  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1115  * skb is freeed here if no mpath could be allocated.
1116  */
1117 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1118                          struct sk_buff *skb)
1119 {
1120         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1121         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1122         struct mesh_path *mpath;
1123         struct sk_buff *skb_to_free = NULL;
1124         u8 *target_addr = hdr->addr3;
1125         int err = 0;
1126
1127         /* Nulls are only sent to peers for PS and should be pre-addressed */
1128         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1129                 return 0;
1130
1131         rcu_read_lock();
1132         err = mesh_nexthop_lookup(sdata, skb);
1133         if (!err)
1134                 goto endlookup;
1135
1136         /* no nexthop found, start resolving */
1137         mpath = mesh_path_lookup(sdata, target_addr);
1138         if (!mpath) {
1139                 mpath = mesh_path_add(sdata, target_addr);
1140                 if (IS_ERR(mpath)) {
1141                         mesh_path_discard_frame(sdata, skb);
1142                         err = PTR_ERR(mpath);
1143                         goto endlookup;
1144                 }
1145         }
1146
1147         if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1148             mesh_path_sel_is_hwmp(sdata))
1149                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1150
1151         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1152                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1153
1154         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1155         ieee80211_set_qos_hdr(sdata, skb);
1156         skb_queue_tail(&mpath->frame_queue, skb);
1157         err = -ENOENT;
1158         if (skb_to_free)
1159                 mesh_path_discard_frame(sdata, skb_to_free);
1160
1161 endlookup:
1162         rcu_read_unlock();
1163         return err;
1164 }
1165
1166 /**
1167  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1168  * this function is considered "using" the associated mpath, so preempt a path
1169  * refresh if this mpath expires soon.
1170  *
1171  * @skb: 802.11 frame to be sent
1172  * @sdata: network subif the frame will be sent through
1173  *
1174  * Returns: 0 if the next hop was found. Nonzero otherwise.
1175  */
1176 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1177                         struct sk_buff *skb)
1178 {
1179         struct mesh_path *mpath;
1180         struct sta_info *next_hop;
1181         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1182         u8 *target_addr = hdr->addr3;
1183         int err = -ENOENT;
1184
1185         rcu_read_lock();
1186         mpath = mesh_path_lookup(sdata, target_addr);
1187
1188         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1189                 goto endlookup;
1190
1191         if (time_after(jiffies,
1192                        mpath->exp_time -
1193                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1194             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1195             !(mpath->flags & MESH_PATH_RESOLVING) &&
1196             !(mpath->flags & MESH_PATH_FIXED))
1197                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1198
1199         next_hop = rcu_dereference(mpath->next_hop);
1200         if (next_hop) {
1201                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1202                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1203                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1204                 err = 0;
1205         }
1206
1207 endlookup:
1208         rcu_read_unlock();
1209         return err;
1210 }
1211
1212 void mesh_path_timer(unsigned long data)
1213 {
1214         struct mesh_path *mpath = (void *) data;
1215         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1216         int ret;
1217
1218         if (sdata->local->quiescing)
1219                 return;
1220
1221         spin_lock_bh(&mpath->state_lock);
1222         if (mpath->flags & MESH_PATH_RESOLVED ||
1223                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1224                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1225                 spin_unlock_bh(&mpath->state_lock);
1226         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1227                 ++mpath->discovery_retries;
1228                 mpath->discovery_timeout *= 2;
1229                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1230                 spin_unlock_bh(&mpath->state_lock);
1231                 mesh_queue_preq(mpath, 0);
1232         } else {
1233                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1234                                   MESH_PATH_RESOLVED |
1235                                   MESH_PATH_REQ_QUEUED);
1236                 mpath->exp_time = jiffies;
1237                 spin_unlock_bh(&mpath->state_lock);
1238                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1239                         ret = mesh_path_send_to_gates(mpath);
1240                         if (ret)
1241                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1242                 } else
1243                         mesh_path_flush_pending(mpath);
1244         }
1245 }
1246
1247 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1248 {
1249         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1250         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1251         u8 flags, target_flags = 0;
1252
1253         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1254                         ? RANN_FLAG_IS_GATE : 0;
1255
1256         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1257         case IEEE80211_PROACTIVE_RANN:
1258                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1259                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1260                                        0, ifmsh->mshcfg.element_ttl,
1261                                        interval, 0, 0, sdata);
1262                 break;
1263         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1264                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1265         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1266                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1267                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1268                                 IEEE80211_PREQ_USN_FLAG;
1269                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1270                                        ++ifmsh->sn, target_flags,
1271                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1272                                        0, ifmsh->mshcfg.element_ttl, interval,
1273                                        0, ifmsh->preq_id++, sdata);
1274                 break;
1275         default:
1276                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1277                 return;
1278         }
1279 }