net/mac80211/mesh_hwmp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2008, 2009 open80211s Ltd.
   4  * Copyright (C) 2019 Intel Corporation
   5  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   6  */
   7
   8 #include <linux/slab.h>
   9 #include <linux/etherdevice.h>
  10 #include <asm/unaligned.h>
  11 #include "wme.h"
  12 #include "mesh.h"
  13
  14 #define TEST_FRAME_LEN  8192
  15 #define MAX_METRIC      0xffffffff
  16 #define ARITH_SHIFT     8
  17 #define LINK_FAIL_THRESH 95
  18
  19 #define MAX_PREQ_QUEUE_LEN      64
  20
  21 static void mesh_queue_preq(struct mesh_path *, u8);
  22
  23 static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
  24 {
  25         if (ae)
  26                 offset += 6;
  27         return get_unaligned_le32(preq_elem + offset);
  28 }
  29
  30 static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
  31 {
  32         if (ae)
  33                 offset += 6;
  34         return get_unaligned_le16(preq_elem + offset);
  35 }
  36
  37 /* HWMP IE processing macros */
  38 #define AE_F                    (1<<6)
  39 #define AE_F_SET(x)             (*x & AE_F)
  40 #define PREQ_IE_FLAGS(x)        (*(x))
  41 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  42 #define PREQ_IE_TTL(x)          (*(x + 2))
  43 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  44 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  45 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  46 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  47 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  48 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  49 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  50 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  51
  52
  53 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  54 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  55 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  56 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  57 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  58 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  59 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  60 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  61 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  62
  63 #define PERR_IE_TTL(x)          (*(x))
  64 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  65 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  66 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  67 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  68
  69 #define MSEC_TO_TU(x) (x*1000/1024)
  70 #define SN_GT(x, y) ((s32)(y - x) < 0)
  71 #define SN_LT(x, y) ((s32)(x - y) < 0)
  72 #define MAX_SANE_SN_DELTA 32
  73
  74 static inline u32 SN_DELTA(u32 x, u32 y)
  75 {
  76         return x >= y ? x - y : y - x;
  77 }
  78
  79 #define net_traversal_jiffies(s) \
  80         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  81 #define default_lifetime(s) \
  82         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  83 #define min_preq_int_jiff(s) \
  84         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  85 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  86 #define disc_timeout_jiff(s) \
  87         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  88 #define root_path_confirmation_jiffies(s) \
  89         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  90
  91 enum mpath_frame_type {
  92         MPATH_PREQ = 0,
  93         MPATH_PREP,
  94         MPATH_PERR,
  95         MPATH_RANN
  96 };
  97
  98 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
  99
 100 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 101                                   const u8 *orig_addr, u32 orig_sn,
 102                                   u8 target_flags, const u8 *target,
 103                                   u32 target_sn, const u8 *da,
 104                                   u8 hop_count, u8 ttl,
 105                                   u32 lifetime, u32 metric, u32 preq_id,
 106                                   struct ieee80211_sub_if_data *sdata)
 107 {
 108         struct ieee80211_local *local = sdata->local;
 109         struct sk_buff *skb;
 110         struct ieee80211_mgmt *mgmt;
 111         u8 *pos, ie_len;
 112         int hdr_len = offsetofend(struct ieee80211_mgmt,
 113                                   u.action.u.mesh_action);
 114
 115         skb = dev_alloc_skb(local->tx_headroom +
 116                             hdr_len +
 117                             2 + 37); /* max HWMP IE */
 118         if (!skb)
 119                 return -1;
 120         skb_reserve(skb, local->tx_headroom);
 121         mgmt = skb_put_zero(skb, hdr_len);
 122         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 123                                           IEEE80211_STYPE_ACTION);
 124
 125         memcpy(mgmt->da, da, ETH_ALEN);
 126         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 127         /* BSSID == SA */
 128         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 129         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 130         mgmt->u.action.u.mesh_action.action_code =
 131                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 132
 133         switch (action) {
 134         case MPATH_PREQ:
 135                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 136                 ie_len = 37;
 137                 pos = skb_put(skb, 2 + ie_len);
 138                 *pos++ = WLAN_EID_PREQ;
 139                 break;
 140         case MPATH_PREP:
 141                 mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
 142                 ie_len = 31;
 143                 pos = skb_put(skb, 2 + ie_len);
 144                 *pos++ = WLAN_EID_PREP;
 145                 break;
 146         case MPATH_RANN:
 147                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 148                 ie_len = sizeof(struct ieee80211_rann_ie);
 149                 pos = skb_put(skb, 2 + ie_len);
 150                 *pos++ = WLAN_EID_RANN;
 151                 break;
 152         default:
 153                 kfree_skb(skb);
 154                 return -ENOTSUPP;
 155         }
 156         *pos++ = ie_len;
 157         *pos++ = flags;
 158         *pos++ = hop_count;
 159         *pos++ = ttl;
 160         if (action == MPATH_PREP) {
 161                 memcpy(pos, target, ETH_ALEN);
 162                 pos += ETH_ALEN;
 163                 put_unaligned_le32(target_sn, pos);
 164                 pos += 4;
 165         } else {
 166                 if (action == MPATH_PREQ) {
 167                         put_unaligned_le32(preq_id, pos);
 168                         pos += 4;
 169                 }
 170                 memcpy(pos, orig_addr, ETH_ALEN);
 171                 pos += ETH_ALEN;
 172                 put_unaligned_le32(orig_sn, pos);
 173                 pos += 4;
 174         }
 175         put_unaligned_le32(lifetime, pos); /* interval for RANN */
 176         pos += 4;
 177         put_unaligned_le32(metric, pos);
 178         pos += 4;
 179         if (action == MPATH_PREQ) {
 180                 *pos++ = 1; /* destination count */
 181                 *pos++ = target_flags;
 182                 memcpy(pos, target, ETH_ALEN);
 183                 pos += ETH_ALEN;
 184                 put_unaligned_le32(target_sn, pos);
 185                 pos += 4;
 186         } else if (action == MPATH_PREP) {
 187                 memcpy(pos, orig_addr, ETH_ALEN);
 188                 pos += ETH_ALEN;
 189                 put_unaligned_le32(orig_sn, pos);
 190                 pos += 4;
 191         }
 192
 193         ieee80211_tx_skb(sdata, skb);
 194         return 0;
 195 }
 196
 197
 198 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 199  *  headroom in case the frame is encrypted. */
 200 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 201                 struct sk_buff *skb)
 202 {
 203         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 204         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 205
 206         skb_reset_mac_header(skb);
 207         skb_reset_network_header(skb);
 208         skb_reset_transport_header(skb);
 209
 210         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 211         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 212         skb->priority = 7;
 213
 214         info->control.vif = &sdata->vif;
 215         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 216         ieee80211_set_qos_hdr(sdata, skb);
 217         ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
 218 }
 219
 220 /**
 221  * mesh_path_error_tx - Sends a PERR mesh management frame
 222  *
 223  * @ttl: allowed remaining hops
 224  * @target: broken destination
 225  * @target_sn: SN of the broken destination
 226  * @target_rcode: reason code for this PERR
 227  * @ra: node this frame is addressed to
 228  * @sdata: local mesh subif
 229  *
 230  * Note: This function may be called with driver locks taken that the driver
 231  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 232  * frame directly but add it to the pending queue instead.
 233  */
 234 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 235                        u8 ttl, const u8 *target, u32 target_sn,
 236                        u16 target_rcode, const u8 *ra)
 237 {
 238         struct ieee80211_local *local = sdata->local;
 239         struct sk_buff *skb;
 240         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 241         struct ieee80211_mgmt *mgmt;
 242         u8 *pos, ie_len;
 243         int hdr_len = offsetofend(struct ieee80211_mgmt,
 244                                   u.action.u.mesh_action);
 245
 246         if (time_before(jiffies, ifmsh->next_perr))
 247                 return -EAGAIN;
 248
 249         skb = dev_alloc_skb(local->tx_headroom +
 250                             sdata->encrypt_headroom +
 251                             IEEE80211_ENCRYPT_TAILROOM +
 252                             hdr_len +
 253                             2 + 15 /* PERR IE */);
 254         if (!skb)
 255                 return -1;
 256         skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom);
 257         mgmt = skb_put_zero(skb, hdr_len);
 258         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 259                                           IEEE80211_STYPE_ACTION);
 260
 261         memcpy(mgmt->da, ra, ETH_ALEN);
 262         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 263         /* BSSID == SA */
 264         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 265         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 266         mgmt->u.action.u.mesh_action.action_code =
 267                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 268         ie_len = 15;
 269         pos = skb_put(skb, 2 + ie_len);
 270         *pos++ = WLAN_EID_PERR;
 271         *pos++ = ie_len;
 272         /* ttl */
 273         *pos++ = ttl;
 274         /* number of destinations */
 275         *pos++ = 1;
 276         /* Flags field has AE bit only as defined in
 277          * sec 8.4.2.117 IEEE802.11-2012
 278          */
 279         *pos = 0;
 280         pos++;
 281         memcpy(pos, target, ETH_ALEN);
 282         pos += ETH_ALEN;
 283         put_unaligned_le32(target_sn, pos);
 284         pos += 4;
 285         put_unaligned_le16(target_rcode, pos);
 286
 287         /* see note in function header */
 288         prepare_frame_for_deferred_tx(sdata, skb);
 289         ifmsh->next_perr = TU_TO_EXP_TIME(
 290                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 291         ieee80211_add_pending_skb(local, skb);
 292         return 0;
 293 }
 294
 295 void ieee80211s_update_metric(struct ieee80211_local *local,
 296                               struct sta_info *sta,
 297                               struct ieee80211_tx_status *st)
 298 {
 299         struct ieee80211_tx_info *txinfo = st->info;
 300         int failed;
 301         struct rate_info rinfo;
 302
 303         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 304
 305         /* moving average, scaled to 100.
 306          * feed failure as 100 and success as 0
 307          */
 308         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
 309         if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
 310                         LINK_FAIL_THRESH)
 311                 mesh_plink_broken(sta);
 312
 313         sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
 314         ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg,
 315                                   cfg80211_calculate_bitrate(&rinfo));
 316 }
 317
 318 u32 airtime_link_metric_get(struct ieee80211_local *local,
 319                             struct sta_info *sta)
 320 {
 321         /* This should be adjusted for each device */
 322         int device_constant = 1 << ARITH_SHIFT;
 323         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 324         int s_unit = 1 << ARITH_SHIFT;
 325         int rate, err;
 326         u32 tx_time, estimated_retx;
 327         u64 result;
 328         unsigned long fail_avg =
 329                 ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
 330
 331         /* Try to get rate based on HW/SW RC algorithm.
 332          * Rate is returned in units of Kbps, correct this
 333          * to comply with airtime calculation units
 334          * Round up in case we get rate < 100Kbps
 335          */
 336         rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
 337
 338         if (rate) {
 339                 err = 0;
 340         } else {
 341                 if (fail_avg > LINK_FAIL_THRESH)
 342                         return MAX_METRIC;
 343
 344                 rate = ewma_mesh_tx_rate_avg_read(&sta->mesh->tx_rate_avg);
 345                 if (WARN_ON(!rate))
 346                         return MAX_METRIC;
 347
 348                 err = (fail_avg << ARITH_SHIFT) / 100;
 349         }
 350
 351         /* bitrate is in units of 100 Kbps, while we need rate in units of
 352          * 1Mbps. This will be corrected on tx_time computation.
 353          */
 354         tx_time = (device_constant + 10 * test_frame_len / rate);
 355         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 356         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
 357         return (u32)result;
 358 }
 359
 360 /**
 361  * hwmp_route_info_get - Update routing info to originator and transmitter
 362  *
 363  * @sdata: local mesh subif
 364  * @mgmt: mesh management frame
 365  * @hwmp_ie: hwmp information element (PREP or PREQ)
 366  * @action: type of hwmp ie
 367  *
 368  * This function updates the path routing information to the originator and the
 369  * transmitter of a HWMP PREQ or PREP frame.
 370  *
 371  * Returns: metric to frame originator or 0 if the frame should not be further
 372  * processed
 373  *
 374  * Notes: this function is the only place (besides user-provided info) where
 375  * path routing information is updated.
 376  */
 377 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 378                                struct ieee80211_mgmt *mgmt,
 379                                const u8 *hwmp_ie, enum mpath_frame_type action)
 380 {
 381         struct ieee80211_local *local = sdata->local;
 382         struct mesh_path *mpath;
 383         struct sta_info *sta;
 384         bool fresh_info;
 385         const u8 *orig_addr, *ta;
 386         u32 orig_sn, orig_metric;
 387         unsigned long orig_lifetime, exp_time;
 388         u32 last_hop_metric, new_metric;
 389         bool process = true;
 390         u8 hopcount;
 391
 392         rcu_read_lock();
 393         sta = sta_info_get(sdata, mgmt->sa);
 394         if (!sta) {
 395                 rcu_read_unlock();
 396                 return 0;
 397         }
 398
 399         last_hop_metric = airtime_link_metric_get(local, sta);
 400         /* Update and check originator routing info */
 401         fresh_info = true;
 402
 403         switch (action) {
 404         case MPATH_PREQ:
 405                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 406                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 407                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 408                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 409                 hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1;
 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                 hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1;
 422                 break;
 423         default:
 424                 rcu_read_unlock();
 425                 return 0;
 426         }
 427         new_metric = orig_metric + last_hop_metric;
 428         if (new_metric < orig_metric)
 429                 new_metric = MAX_METRIC;
 430         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 431
 432         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 433                 /* This MP is the originator, we are not interested in this
 434                  * frame, except for updating transmitter's path info.
 435                  */
 436                 process = false;
 437                 fresh_info = false;
 438         } else {
 439                 mpath = mesh_path_lookup(sdata, orig_addr);
 440                 if (mpath) {
 441                         spin_lock_bh(&mpath->state_lock);
 442                         if (mpath->flags & MESH_PATH_FIXED)
 443                                 fresh_info = false;
 444                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 445                             (mpath->flags & MESH_PATH_SN_VALID)) {
 446                                 if (SN_GT(mpath->sn, orig_sn) ||
 447                                     (mpath->sn == orig_sn &&
 448                                      (rcu_access_pointer(mpath->next_hop) !=
 449                                                       sta ?
 450                                               mult_frac(new_metric, 10, 9) :
 451                                               new_metric) >= mpath->metric)) {
 452                                         process = false;
 453                                         fresh_info = false;
 454                                 }
 455                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 456                                 bool have_sn, newer_sn, bounced;
 457
 458                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 459                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 460                                 bounced = have_sn &&
 461                                           (SN_DELTA(orig_sn, mpath->sn) >
 462                                                         MAX_SANE_SN_DELTA);
 463
 464                                 if (!have_sn || newer_sn) {
 465                                         /* if SN is newer than what we had
 466                                          * then we can take it */;
 467                                 } else if (bounced) {
 468                                         /* if SN is way different than what
 469                                          * we had then assume the other side
 470                                          * rebooted or restarted */;
 471                                 } else {
 472                                         process = false;
 473                                         fresh_info = false;
 474                                 }
 475                         }
 476                 } else {
 477                         mpath = mesh_path_add(sdata, orig_addr);
 478                         if (IS_ERR(mpath)) {
 479                                 rcu_read_unlock();
 480                                 return 0;
 481                         }
 482                         spin_lock_bh(&mpath->state_lock);
 483                 }
 484
 485                 if (fresh_info) {
 486                         if (rcu_access_pointer(mpath->next_hop) != sta)
 487                                 mpath->path_change_count++;
 488                         mesh_path_assign_nexthop(mpath, sta);
 489                         mpath->flags |= MESH_PATH_SN_VALID;
 490                         mpath->metric = new_metric;
 491                         mpath->sn = orig_sn;
 492                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 493                                           ?  mpath->exp_time : exp_time;
 494                         mpath->hop_count = hopcount;
 495                         mesh_path_activate(mpath);
 496                         spin_unlock_bh(&mpath->state_lock);
 497                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 498                         /* init it at a low value - 0 start is tricky */
 499                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 500                         mesh_path_tx_pending(mpath);
 501                         /* draft says preq_id should be saved to, but there does
 502                          * not seem to be any use for it, skipping by now
 503                          */
 504                 } else
 505                         spin_unlock_bh(&mpath->state_lock);
 506         }
 507
 508         /* Update and check transmitter routing info */
 509         ta = mgmt->sa;
 510         if (ether_addr_equal(orig_addr, ta))
 511                 fresh_info = false;
 512         else {
 513                 fresh_info = true;
 514
 515                 mpath = mesh_path_lookup(sdata, ta);
 516                 if (mpath) {
 517                         spin_lock_bh(&mpath->state_lock);
 518                         if ((mpath->flags & MESH_PATH_FIXED) ||
 519                             ((mpath->flags & MESH_PATH_ACTIVE) &&
 520                              ((rcu_access_pointer(mpath->next_hop) != sta ?
 521                                        mult_frac(last_hop_metric, 10, 9) :
 522                                        last_hop_metric) > mpath->metric)))
 523                                 fresh_info = false;
 524                 } else {
 525                         mpath = mesh_path_add(sdata, ta);
 526                         if (IS_ERR(mpath)) {
 527                                 rcu_read_unlock();
 528                                 return 0;
 529                         }
 530                         spin_lock_bh(&mpath->state_lock);
 531                 }
 532
 533                 if (fresh_info) {
 534                         if (rcu_access_pointer(mpath->next_hop) != sta)
 535                                 mpath->path_change_count++;
 536                         mesh_path_assign_nexthop(mpath, sta);
 537                         mpath->metric = last_hop_metric;
 538                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 539                                           ?  mpath->exp_time : exp_time;
 540                         mpath->hop_count = 1;
 541                         mesh_path_activate(mpath);
 542                         spin_unlock_bh(&mpath->state_lock);
 543                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 544                         /* init it at a low value - 0 start is tricky */
 545                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 546                         mesh_path_tx_pending(mpath);
 547                 } else
 548                         spin_unlock_bh(&mpath->state_lock);
 549         }
 550
 551         rcu_read_unlock();
 552
 553         return process ? new_metric : 0;
 554 }
 555
 556 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 557                                     struct ieee80211_mgmt *mgmt,
 558                                     const u8 *preq_elem, u32 orig_metric)
 559 {
 560         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 561         struct mesh_path *mpath = NULL;
 562         const u8 *target_addr, *orig_addr;
 563         const u8 *da;
 564         u8 target_flags, ttl, flags;
 565         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 566         bool reply = false;
 567         bool forward = true;
 568         bool root_is_gate;
 569
 570         /* Update target SN, if present */
 571         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 572         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 573         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 574         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 575         target_flags = PREQ_IE_TARGET_F(preq_elem);
 576         /* Proactive PREQ gate announcements */
 577         flags = PREQ_IE_FLAGS(preq_elem);
 578         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 579
 580         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 581
 582         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 583                 mhwmp_dbg(sdata, "PREQ is for us\n");
 584                 forward = false;
 585                 reply = true;
 586                 target_metric = 0;
 587
 588                 if (SN_GT(target_sn, ifmsh->sn))
 589                         ifmsh->sn = target_sn;
 590
 591                 if (time_after(jiffies, ifmsh->last_sn_update +
 592                                         net_traversal_jiffies(sdata)) ||
 593                     time_before(jiffies, ifmsh->last_sn_update)) {
 594                         ++ifmsh->sn;
 595                         ifmsh->last_sn_update = jiffies;
 596                 }
 597                 target_sn = ifmsh->sn;
 598         } else if (is_broadcast_ether_addr(target_addr) &&
 599                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 600                 rcu_read_lock();
 601                 mpath = mesh_path_lookup(sdata, orig_addr);
 602                 if (mpath) {
 603                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 604                                 reply = true;
 605                                 target_addr = sdata->vif.addr;
 606                                 target_sn = ++ifmsh->sn;
 607                                 target_metric = 0;
 608                                 ifmsh->last_sn_update = jiffies;
 609                         }
 610                         if (root_is_gate)
 611                                 mesh_path_add_gate(mpath);
 612                 }
 613                 rcu_read_unlock();
 614         } else {
 615                 rcu_read_lock();
 616                 mpath = mesh_path_lookup(sdata, target_addr);
 617                 if (mpath) {
 618                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 619                                         SN_LT(mpath->sn, target_sn)) {
 620                                 mpath->sn = target_sn;
 621                                 mpath->flags |= MESH_PATH_SN_VALID;
 622                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 623                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 624                                 reply = true;
 625                                 target_metric = mpath->metric;
 626                                 target_sn = mpath->sn;
 627                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 628                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 629                         }
 630                 }
 631                 rcu_read_unlock();
 632         }
 633
 634         if (reply) {
 635                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 636                 ttl = ifmsh->mshcfg.element_ttl;
 637                 if (ttl != 0) {
 638                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 639                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 640                                                orig_sn, 0, target_addr,
 641                                                target_sn, mgmt->sa, 0, ttl,
 642                                                lifetime, target_metric, 0,
 643                                                sdata);
 644                 } else {
 645                         ifmsh->mshstats.dropped_frames_ttl++;
 646                 }
 647         }
 648
 649         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 650                 u32 preq_id;
 651                 u8 hopcount;
 652
 653                 ttl = PREQ_IE_TTL(preq_elem);
 654                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 655                 if (ttl <= 1) {
 656                         ifmsh->mshstats.dropped_frames_ttl++;
 657                         return;
 658                 }
 659                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 660                 --ttl;
 661                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 662                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 663                 da = (mpath && mpath->is_root) ?
 664                         mpath->rann_snd_addr : broadcast_addr;
 665
 666                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 667                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 668                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 669                 }
 670
 671                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 672                                        orig_sn, target_flags, target_addr,
 673                                        target_sn, da, hopcount, ttl, lifetime,
 674                                        orig_metric, preq_id, sdata);
 675                 if (!is_multicast_ether_addr(da))
 676                         ifmsh->mshstats.fwded_unicast++;
 677                 else
 678                         ifmsh->mshstats.fwded_mcast++;
 679                 ifmsh->mshstats.fwded_frames++;
 680         }
 681 }
 682
 683
 684 static inline struct sta_info *
 685 next_hop_deref_protected(struct mesh_path *mpath)
 686 {
 687         return rcu_dereference_protected(mpath->next_hop,
 688                                          lockdep_is_held(&mpath->state_lock));
 689 }
 690
 691
 692 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 693                                     struct ieee80211_mgmt *mgmt,
 694                                     const u8 *prep_elem, u32 metric)
 695 {
 696         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 697         struct mesh_path *mpath;
 698         const u8 *target_addr, *orig_addr;
 699         u8 ttl, hopcount, flags;
 700         u8 next_hop[ETH_ALEN];
 701         u32 target_sn, orig_sn, lifetime;
 702
 703         mhwmp_dbg(sdata, "received PREP from %pM\n",
 704                   PREP_IE_TARGET_ADDR(prep_elem));
 705
 706         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 707         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 708                 /* destination, no forwarding required */
 709                 return;
 710
 711         if (!ifmsh->mshcfg.dot11MeshForwarding)
 712                 return;
 713
 714         ttl = PREP_IE_TTL(prep_elem);
 715         if (ttl <= 1) {
 716                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 717                 return;
 718         }
 719
 720         rcu_read_lock();
 721         mpath = mesh_path_lookup(sdata, orig_addr);
 722         if (mpath)
 723                 spin_lock_bh(&mpath->state_lock);
 724         else
 725                 goto fail;
 726         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 727                 spin_unlock_bh(&mpath->state_lock);
 728                 goto fail;
 729         }
 730         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 731         spin_unlock_bh(&mpath->state_lock);
 732         --ttl;
 733         flags = PREP_IE_FLAGS(prep_elem);
 734         lifetime = PREP_IE_LIFETIME(prep_elem);
 735         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 736         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 737         target_sn = PREP_IE_TARGET_SN(prep_elem);
 738         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 739
 740         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 741                                target_addr, target_sn, next_hop, hopcount,
 742                                ttl, lifetime, metric, 0, sdata);
 743         rcu_read_unlock();
 744
 745         sdata->u.mesh.mshstats.fwded_unicast++;
 746         sdata->u.mesh.mshstats.fwded_frames++;
 747         return;
 748
 749 fail:
 750         rcu_read_unlock();
 751         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 752 }
 753
 754 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 755                                     struct ieee80211_mgmt *mgmt,
 756                                     const u8 *perr_elem)
 757 {
 758         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 759         struct mesh_path *mpath;
 760         u8 ttl;
 761         const u8 *ta, *target_addr;
 762         u32 target_sn;
 763         u16 target_rcode;
 764
 765         ta = mgmt->sa;
 766         ttl = PERR_IE_TTL(perr_elem);
 767         if (ttl <= 1) {
 768                 ifmsh->mshstats.dropped_frames_ttl++;
 769                 return;
 770         }
 771         ttl--;
 772         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 773         target_sn = PERR_IE_TARGET_SN(perr_elem);
 774         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 775
 776         rcu_read_lock();
 777         mpath = mesh_path_lookup(sdata, target_addr);
 778         if (mpath) {
 779                 struct sta_info *sta;
 780
 781                 spin_lock_bh(&mpath->state_lock);
 782                 sta = next_hop_deref_protected(mpath);
 783                 if (mpath->flags & MESH_PATH_ACTIVE &&
 784                     ether_addr_equal(ta, sta->sta.addr) &&
 785                     !(mpath->flags & MESH_PATH_FIXED) &&
 786                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 787                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 788                         mpath->flags &= ~MESH_PATH_ACTIVE;
 789                         if (target_sn != 0)
 790                                 mpath->sn = target_sn;
 791                         else
 792                                 mpath->sn += 1;
 793                         spin_unlock_bh(&mpath->state_lock);
 794                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 795                                 goto endperr;
 796                         mesh_path_error_tx(sdata, ttl, target_addr,
 797                                            target_sn, target_rcode,
 798                                            broadcast_addr);
 799                 } else
 800                         spin_unlock_bh(&mpath->state_lock);
 801         }
 802 endperr:
 803         rcu_read_unlock();
 804 }
 805
 806 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 807                                     struct ieee80211_mgmt *mgmt,
 808                                     const struct ieee80211_rann_ie *rann)
 809 {
 810         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 811         struct ieee80211_local *local = sdata->local;
 812         struct sta_info *sta;
 813         struct mesh_path *mpath;
 814         u8 ttl, flags, hopcount;
 815         const u8 *orig_addr;
 816         u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
 817         bool root_is_gate;
 818
 819         ttl = rann->rann_ttl;
 820         flags = rann->rann_flags;
 821         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 822         orig_addr = rann->rann_addr;
 823         orig_sn = le32_to_cpu(rann->rann_seq);
 824         interval = le32_to_cpu(rann->rann_interval);
 825         hopcount = rann->rann_hopcount;
 826         hopcount++;
 827         orig_metric = le32_to_cpu(rann->rann_metric);
 828
 829         /*  Ignore our own RANNs */
 830         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 831                 return;
 832
 833         mhwmp_dbg(sdata,
 834                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 835                   orig_addr, mgmt->sa, root_is_gate);
 836
 837         rcu_read_lock();
 838         sta = sta_info_get(sdata, mgmt->sa);
 839         if (!sta) {
 840                 rcu_read_unlock();
 841                 return;
 842         }
 843
 844         last_hop_metric = airtime_link_metric_get(local, sta);
 845         new_metric = orig_metric + last_hop_metric;
 846         if (new_metric < orig_metric)
 847                 new_metric = MAX_METRIC;
 848
 849         mpath = mesh_path_lookup(sdata, orig_addr);
 850         if (!mpath) {
 851                 mpath = mesh_path_add(sdata, orig_addr);
 852                 if (IS_ERR(mpath)) {
 853                         rcu_read_unlock();
 854                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 855                         return;
 856                 }
 857         }
 858
 859         if (!(SN_LT(mpath->sn, orig_sn)) &&
 860             !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
 861                 rcu_read_unlock();
 862                 return;
 863         }
 864
 865         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 866              (time_after(jiffies, mpath->last_preq_to_root +
 867                                   root_path_confirmation_jiffies(sdata)) ||
 868              time_before(jiffies, mpath->last_preq_to_root))) &&
 869              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 870                 mhwmp_dbg(sdata,
 871                           "time to refresh root mpath %pM\n",
 872                           orig_addr);
 873                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 874                 mpath->last_preq_to_root = jiffies;
 875         }
 876
 877         mpath->sn = orig_sn;
 878         mpath->rann_metric = new_metric;
 879         mpath->is_root = true;
 880         /* Recording RANNs sender address to send individually
 881          * addressed PREQs destined for root mesh STA */
 882         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 883
 884         if (root_is_gate)
 885                 mesh_path_add_gate(mpath);
 886
 887         if (ttl <= 1) {
 888                 ifmsh->mshstats.dropped_frames_ttl++;
 889                 rcu_read_unlock();
 890                 return;
 891         }
 892         ttl--;
 893
 894         if (ifmsh->mshcfg.dot11MeshForwarding) {
 895                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 896                                        orig_sn, 0, NULL, 0, broadcast_addr,
 897                                        hopcount, ttl, interval,
 898                                        new_metric, 0, sdata);
 899         }
 900
 901         rcu_read_unlock();
 902 }
 903
 904
 905 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 906                             struct ieee80211_mgmt *mgmt, size_t len)
 907 {
 908         struct ieee802_11_elems elems;
 909         size_t baselen;
 910         u32 path_metric;
 911         struct sta_info *sta;
 912
 913         /* need action_code */
 914         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 915                 return;
 916
 917         rcu_read_lock();
 918         sta = sta_info_get(sdata, mgmt->sa);
 919         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 920                 rcu_read_unlock();
 921                 return;
 922         }
 923         rcu_read_unlock();
 924
 925         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 926         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 927                                len - baselen, false, &elems, mgmt->bssid, NULL);
 928
 929         if (elems.preq) {
 930                 if (elems.preq_len != 37)
 931                         /* Right now we support just 1 destination and no AE */
 932                         return;
 933                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 934                                                   MPATH_PREQ);
 935                 if (path_metric)
 936                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 937                                                 path_metric);
 938         }
 939         if (elems.prep) {
 940                 if (elems.prep_len != 31)
 941                         /* Right now we support no AE */
 942                         return;
 943                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 944                                                   MPATH_PREP);
 945                 if (path_metric)
 946                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 947                                                 path_metric);
 948         }
 949         if (elems.perr) {
 950                 if (elems.perr_len != 15)
 951                         /* Right now we support only one destination per PERR */
 952                         return;
 953                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 954         }
 955         if (elems.rann)
 956                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 957 }
 958
 959 /**
 960  * mesh_queue_preq - queue a PREQ to a given destination
 961  *
 962  * @mpath: mesh path to discover
 963  * @flags: special attributes of the PREQ to be sent
 964  *
 965  * Locking: the function must be called from within a rcu read lock block.
 966  *
 967  */
 968 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 969 {
 970         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 971         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 972         struct mesh_preq_queue *preq_node;
 973
 974         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 975         if (!preq_node) {
 976                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 977                 return;
 978         }
 979
 980         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 981         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 982                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 983                 kfree(preq_node);
 984                 if (printk_ratelimit())
 985                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 986                 return;
 987         }
 988
 989         spin_lock(&mpath->state_lock);
 990         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 991                 spin_unlock(&mpath->state_lock);
 992                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 993                 kfree(preq_node);
 994                 return;
 995         }
 996
 997         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 998         preq_node->flags = flags;
 999
1000         mpath->flags |= MESH_PATH_REQ_QUEUED;
1001         spin_unlock(&mpath->state_lock);
1002
1003         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
1004         ++ifmsh->preq_queue_len;
1005         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1006
1007         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
1008                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1009
1010         else if (time_before(jiffies, ifmsh->last_preq)) {
1011                 /* avoid long wait if did not send preqs for a long time
1012                  * and jiffies wrapped around
1013                  */
1014                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1015                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1016         } else
1017                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1018                                                 min_preq_int_jiff(sdata));
1019 }
1020
1021 /**
1022  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1023  *
1024  * @sdata: local mesh subif
1025  */
1026 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1027 {
1028         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1029         struct mesh_preq_queue *preq_node;
1030         struct mesh_path *mpath;
1031         u8 ttl, target_flags = 0;
1032         const u8 *da;
1033         u32 lifetime;
1034
1035         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1036         if (!ifmsh->preq_queue_len ||
1037                 time_before(jiffies, ifmsh->last_preq +
1038                                 min_preq_int_jiff(sdata))) {
1039                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1040                 return;
1041         }
1042
1043         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1044                         struct mesh_preq_queue, list);
1045         list_del(&preq_node->list);
1046         --ifmsh->preq_queue_len;
1047         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1048
1049         rcu_read_lock();
1050         mpath = mesh_path_lookup(sdata, preq_node->dst);
1051         if (!mpath)
1052                 goto enddiscovery;
1053
1054         spin_lock_bh(&mpath->state_lock);
1055         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1056                 spin_unlock_bh(&mpath->state_lock);
1057                 goto enddiscovery;
1058         }
1059         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1060         if (preq_node->flags & PREQ_Q_F_START) {
1061                 if (mpath->flags & MESH_PATH_RESOLVING) {
1062                         spin_unlock_bh(&mpath->state_lock);
1063                         goto enddiscovery;
1064                 } else {
1065                         mpath->flags &= ~MESH_PATH_RESOLVED;
1066                         mpath->flags |= MESH_PATH_RESOLVING;
1067                         mpath->discovery_retries = 0;
1068                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1069                 }
1070         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1071                         mpath->flags & MESH_PATH_RESOLVED) {
1072                 mpath->flags &= ~MESH_PATH_RESOLVING;
1073                 spin_unlock_bh(&mpath->state_lock);
1074                 goto enddiscovery;
1075         }
1076
1077         ifmsh->last_preq = jiffies;
1078
1079         if (time_after(jiffies, ifmsh->last_sn_update +
1080                                 net_traversal_jiffies(sdata)) ||
1081             time_before(jiffies, ifmsh->last_sn_update)) {
1082                 ++ifmsh->sn;
1083                 sdata->u.mesh.last_sn_update = jiffies;
1084         }
1085         lifetime = default_lifetime(sdata);
1086         ttl = sdata->u.mesh.mshcfg.element_ttl;
1087         if (ttl == 0) {
1088                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1089                 spin_unlock_bh(&mpath->state_lock);
1090                 goto enddiscovery;
1091         }
1092
1093         if (preq_node->flags & PREQ_Q_F_REFRESH)
1094                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1095         else
1096                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1097
1098         spin_unlock_bh(&mpath->state_lock);
1099         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1100         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1101                                target_flags, mpath->dst, mpath->sn, da, 0,
1102                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1103         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1104
1105 enddiscovery:
1106         rcu_read_unlock();
1107         kfree(preq_node);
1108 }
1109
1110 /**
1111  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1112  *
1113  * @skb: 802.11 frame to be sent
1114  * @sdata: network subif the frame will be sent through
1115  *
1116  * Lookup next hop for given skb and start path discovery if no
1117  * forwarding information is found.
1118  *
1119  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1120  * skb is freeed here if no mpath could be allocated.
1121  */
1122 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1123                          struct sk_buff *skb)
1124 {
1125         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1126         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1127         struct mesh_path *mpath;
1128         struct sk_buff *skb_to_free = NULL;
1129         u8 *target_addr = hdr->addr3;
1130
1131         /* Nulls are only sent to peers for PS and should be pre-addressed */
1132         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1133                 return 0;
1134
1135         /* Allow injected packets to bypass mesh routing */
1136         if (info->control.flags & IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP)
1137                 return 0;
1138
1139         if (!mesh_nexthop_lookup(sdata, skb))
1140                 return 0;
1141
1142         /* no nexthop found, start resolving */
1143         mpath = mesh_path_lookup(sdata, target_addr);
1144         if (!mpath) {
1145                 mpath = mesh_path_add(sdata, target_addr);
1146                 if (IS_ERR(mpath)) {
1147                         mesh_path_discard_frame(sdata, skb);
1148                         return PTR_ERR(mpath);
1149                 }
1150         }
1151
1152         if (!(mpath->flags & MESH_PATH_RESOLVING))
1153                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1154
1155         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1156                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1157
1158         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1159         ieee80211_set_qos_hdr(sdata, skb);
1160         skb_queue_tail(&mpath->frame_queue, skb);
1161         if (skb_to_free)
1162                 mesh_path_discard_frame(sdata, skb_to_free);
1163
1164         return -ENOENT;
1165 }
1166
1167 /**
1168  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1169  * this function is considered "using" the associated mpath, so preempt a path
1170  * refresh if this mpath expires soon.
1171  *
1172  * @skb: 802.11 frame to be sent
1173  * @sdata: network subif the frame will be sent through
1174  *
1175  * Returns: 0 if the next hop was found. Nonzero otherwise.
1176  */
1177 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1178                         struct sk_buff *skb)
1179 {
1180         struct mesh_path *mpath;
1181         struct sta_info *next_hop;
1182         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1183         u8 *target_addr = hdr->addr3;
1184
1185         mpath = mesh_path_lookup(sdata, target_addr);
1186         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1187                 return -ENOENT;
1188
1189         if (time_after(jiffies,
1190                        mpath->exp_time -
1191                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1192             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1193             !(mpath->flags & MESH_PATH_RESOLVING) &&
1194             !(mpath->flags & MESH_PATH_FIXED))
1195                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1196
1197         next_hop = rcu_dereference(mpath->next_hop);
1198         if (next_hop) {
1199                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1200                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1201                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1202                 return 0;
1203         }
1204
1205         return -ENOENT;
1206 }
1207
1208 void mesh_path_timer(struct timer_list *t)
1209 {
1210         struct mesh_path *mpath = from_timer(mpath, t, timer);
1211         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1212         int ret;
1213
1214         if (sdata->local->quiescing)
1215                 return;
1216
1217         spin_lock_bh(&mpath->state_lock);
1218         if (mpath->flags & MESH_PATH_RESOLVED ||
1219                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1220                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1221                 spin_unlock_bh(&mpath->state_lock);
1222         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1223                 ++mpath->discovery_retries;
1224                 mpath->discovery_timeout *= 2;
1225                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1226                 spin_unlock_bh(&mpath->state_lock);
1227                 mesh_queue_preq(mpath, 0);
1228         } else {
1229                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1230                                   MESH_PATH_RESOLVED |
1231                                   MESH_PATH_REQ_QUEUED);
1232                 mpath->exp_time = jiffies;
1233                 spin_unlock_bh(&mpath->state_lock);
1234                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1235                         ret = mesh_path_send_to_gates(mpath);
1236                         if (ret)
1237                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1238                 } else
1239                         mesh_path_flush_pending(mpath);
1240         }
1241 }
1242
1243 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1244 {
1245         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1246         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1247         u8 flags, target_flags = 0;
1248
1249         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1250                         ? RANN_FLAG_IS_GATE : 0;
1251
1252         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1253         case IEEE80211_PROACTIVE_RANN:
1254                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1255                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1256                                        0, ifmsh->mshcfg.element_ttl,
1257                                        interval, 0, 0, sdata);
1258                 break;
1259         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1260                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1261                 /* fall through */
1262         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1263                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1264                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1265                                 IEEE80211_PREQ_USN_FLAG;
1266                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1267                                        ++ifmsh->sn, target_flags,
1268                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1269                                        0, ifmsh->mshcfg.element_ttl, interval,
1270                                        0, ifmsh->preq_id++, sdata);
1271                 break;
1272         default:
1273                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1274                 return;
1275         }
1276 }