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, 2021-2023 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 -EOPNOTSUPP;
 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->control.flags |= IEEE80211_TX_INTCFL_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  * Returns: 0 on success
 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 = offsetofend(struct ieee80211_mgmt,
 246                                   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                             IEEE80211_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 + IEEE80211_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         struct rate_info rinfo;
 304
 305         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 306
 307         /* moving average, scaled to 100.
 308          * feed failure as 100 and success as 0
 309          */
 310         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
 311         if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
 312                         LINK_FAIL_THRESH)
 313                 mesh_plink_broken(sta);
 314
 315         /* use rate info set by the driver directly if present */
 316         if (st->n_rates)
 317                 rinfo = sta->deflink.tx_stats.last_rate_info;
 318         else
 319                 sta_set_rate_info_tx(sta, &sta->deflink.tx_stats.last_rate, &rinfo);
 320
 321         ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg,
 322                                   cfg80211_calculate_bitrate(&rinfo));
 323 }
 324
 325 u32 airtime_link_metric_get(struct ieee80211_local *local,
 326                             struct sta_info *sta)
 327 {
 328         /* This should be adjusted for each device */
 329         int device_constant = 1 << ARITH_SHIFT;
 330         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 331         int s_unit = 1 << ARITH_SHIFT;
 332         int rate, err;
 333         u32 tx_time, estimated_retx;
 334         u64 result;
 335         unsigned long fail_avg =
 336                 ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
 337
 338         if (sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 339                 return MAX_METRIC;
 340
 341         /* Try to get rate based on HW/SW RC algorithm.
 342          * Rate is returned in units of Kbps, correct this
 343          * to comply with airtime calculation units
 344          * Round up in case we get rate < 100Kbps
 345          */
 346         rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
 347
 348         if (rate) {
 349                 err = 0;
 350         } else {
 351                 if (fail_avg > LINK_FAIL_THRESH)
 352                         return MAX_METRIC;
 353
 354                 rate = ewma_mesh_tx_rate_avg_read(&sta->mesh->tx_rate_avg);
 355                 if (WARN_ON(!rate))
 356                         return MAX_METRIC;
 357
 358                 err = (fail_avg << ARITH_SHIFT) / 100;
 359         }
 360
 361         /* bitrate is in units of 100 Kbps, while we need rate in units of
 362          * 1Mbps. This will be corrected on tx_time computation.
 363          */
 364         tx_time = (device_constant + 10 * test_frame_len / rate);
 365         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 366         result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
 367         return (u32)result;
 368 }
 369
 370 /**
 371  * hwmp_route_info_get - Update routing info to originator and transmitter
 372  *
 373  * @sdata: local mesh subif
 374  * @mgmt: mesh management frame
 375  * @hwmp_ie: hwmp information element (PREP or PREQ)
 376  * @action: type of hwmp ie
 377  *
 378  * This function updates the path routing information to the originator and the
 379  * transmitter of a HWMP PREQ or PREP frame.
 380  *
 381  * Returns: metric to frame originator or 0 if the frame should not be further
 382  * processed
 383  *
 384  * Notes: this function is the only place (besides user-provided info) where
 385  * path routing information is updated.
 386  */
 387 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 388                                struct ieee80211_mgmt *mgmt,
 389                                const u8 *hwmp_ie, enum mpath_frame_type action)
 390 {
 391         struct ieee80211_local *local = sdata->local;
 392         struct mesh_path *mpath;
 393         struct sta_info *sta;
 394         bool fresh_info;
 395         const u8 *orig_addr, *ta;
 396         u32 orig_sn, orig_metric;
 397         unsigned long orig_lifetime, exp_time;
 398         u32 last_hop_metric, new_metric;
 399         bool flush_mpath = false;
 400         bool process = true;
 401         u8 hopcount;
 402
 403         rcu_read_lock();
 404         sta = sta_info_get(sdata, mgmt->sa);
 405         if (!sta) {
 406                 rcu_read_unlock();
 407                 return 0;
 408         }
 409
 410         last_hop_metric = airtime_link_metric_get(local, sta);
 411         /* Update and check originator routing info */
 412         fresh_info = true;
 413
 414         switch (action) {
 415         case MPATH_PREQ:
 416                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 417                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 418                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 419                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 420                 hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1;
 421                 break;
 422         case MPATH_PREP:
 423                 /* Originator here refers to the MP that was the target in the
 424                  * Path Request. We divert from the nomenclature in the draft
 425                  * so that we can easily use a single function to gather path
 426                  * information from both PREQ and PREP frames.
 427                  */
 428                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 429                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 430                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 431                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 432                 hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1;
 433                 break;
 434         default:
 435                 rcu_read_unlock();
 436                 return 0;
 437         }
 438         new_metric = orig_metric + last_hop_metric;
 439         if (new_metric < orig_metric)
 440                 new_metric = MAX_METRIC;
 441         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 442
 443         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 444                 /* This MP is the originator, we are not interested in this
 445                  * frame, except for updating transmitter's path info.
 446                  */
 447                 process = false;
 448                 fresh_info = false;
 449         } else {
 450                 mpath = mesh_path_lookup(sdata, orig_addr);
 451                 if (mpath) {
 452                         spin_lock_bh(&mpath->state_lock);
 453                         if (mpath->flags & MESH_PATH_FIXED)
 454                                 fresh_info = false;
 455                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 456                             (mpath->flags & MESH_PATH_SN_VALID)) {
 457                                 if (SN_GT(mpath->sn, orig_sn) ||
 458                                     (mpath->sn == orig_sn &&
 459                                      (rcu_access_pointer(mpath->next_hop) !=
 460                                                       sta ?
 461                                               mult_frac(new_metric, 10, 9) :
 462                                               new_metric) >= mpath->metric)) {
 463                                         process = false;
 464                                         fresh_info = false;
 465                                 }
 466                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 467                                 bool have_sn, newer_sn, bounced;
 468
 469                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 470                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 471                                 bounced = have_sn &&
 472                                           (SN_DELTA(orig_sn, mpath->sn) >
 473                                                         MAX_SANE_SN_DELTA);
 474
 475                                 if (!have_sn || newer_sn) {
 476                                         /* if SN is newer than what we had
 477                                          * then we can take it */;
 478                                 } else if (bounced) {
 479                                         /* if SN is way different than what
 480                                          * we had then assume the other side
 481                                          * rebooted or restarted */;
 482                                 } else {
 483                                         process = false;
 484                                         fresh_info = false;
 485                                 }
 486                         }
 487                 } else {
 488                         mpath = mesh_path_add(sdata, orig_addr);
 489                         if (IS_ERR(mpath)) {
 490                                 rcu_read_unlock();
 491                                 return 0;
 492                         }
 493                         spin_lock_bh(&mpath->state_lock);
 494                 }
 495
 496                 if (fresh_info) {
 497                         if (rcu_access_pointer(mpath->next_hop) != sta) {
 498                                 mpath->path_change_count++;
 499                                 flush_mpath = true;
 500                         }
 501                         mesh_path_assign_nexthop(mpath, sta);
 502                         mpath->flags |= MESH_PATH_SN_VALID;
 503                         mpath->metric = new_metric;
 504                         mpath->sn = orig_sn;
 505                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 506                                           ?  mpath->exp_time : exp_time;
 507                         mpath->hop_count = hopcount;
 508                         mesh_path_activate(mpath);
 509                         spin_unlock_bh(&mpath->state_lock);
 510                         if (flush_mpath)
 511                                 mesh_fast_tx_flush_mpath(mpath);
 512                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 513                         /* init it at a low value - 0 start is tricky */
 514                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 515                         mesh_path_tx_pending(mpath);
 516                         /* draft says preq_id should be saved to, but there does
 517                          * not seem to be any use for it, skipping by now
 518                          */
 519                 } else
 520                         spin_unlock_bh(&mpath->state_lock);
 521         }
 522
 523         /* Update and check transmitter routing info */
 524         ta = mgmt->sa;
 525         if (ether_addr_equal(orig_addr, ta))
 526                 fresh_info = false;
 527         else {
 528                 fresh_info = true;
 529
 530                 mpath = mesh_path_lookup(sdata, ta);
 531                 if (mpath) {
 532                         spin_lock_bh(&mpath->state_lock);
 533                         if ((mpath->flags & MESH_PATH_FIXED) ||
 534                             ((mpath->flags & MESH_PATH_ACTIVE) &&
 535                              ((rcu_access_pointer(mpath->next_hop) != sta ?
 536                                        mult_frac(last_hop_metric, 10, 9) :
 537                                        last_hop_metric) > mpath->metric)))
 538                                 fresh_info = false;
 539                 } else {
 540                         mpath = mesh_path_add(sdata, ta);
 541                         if (IS_ERR(mpath)) {
 542                                 rcu_read_unlock();
 543                                 return 0;
 544                         }
 545                         spin_lock_bh(&mpath->state_lock);
 546                 }
 547
 548                 if (fresh_info) {
 549                         if (rcu_access_pointer(mpath->next_hop) != sta) {
 550                                 mpath->path_change_count++;
 551                                 flush_mpath = true;
 552                         }
 553                         mesh_path_assign_nexthop(mpath, sta);
 554                         mpath->metric = last_hop_metric;
 555                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 556                                           ?  mpath->exp_time : exp_time;
 557                         mpath->hop_count = 1;
 558                         mesh_path_activate(mpath);
 559                         spin_unlock_bh(&mpath->state_lock);
 560                         if (flush_mpath)
 561                                 mesh_fast_tx_flush_mpath(mpath);
 562                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 563                         /* init it at a low value - 0 start is tricky */
 564                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 565                         mesh_path_tx_pending(mpath);
 566                 } else
 567                         spin_unlock_bh(&mpath->state_lock);
 568         }
 569
 570         rcu_read_unlock();
 571
 572         return process ? new_metric : 0;
 573 }
 574
 575 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 576                                     struct ieee80211_mgmt *mgmt,
 577                                     const u8 *preq_elem, u32 orig_metric)
 578 {
 579         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 580         struct mesh_path *mpath = NULL;
 581         const u8 *target_addr, *orig_addr;
 582         const u8 *da;
 583         u8 target_flags, ttl, flags;
 584         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 585         bool reply = false;
 586         bool forward = true;
 587         bool root_is_gate;
 588
 589         /* Update target SN, if present */
 590         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 591         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 592         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 593         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 594         target_flags = PREQ_IE_TARGET_F(preq_elem);
 595         /* Proactive PREQ gate announcements */
 596         flags = PREQ_IE_FLAGS(preq_elem);
 597         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 598
 599         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 600
 601         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 602                 mhwmp_dbg(sdata, "PREQ is for us\n");
 603                 forward = false;
 604                 reply = true;
 605                 target_metric = 0;
 606
 607                 if (SN_GT(target_sn, ifmsh->sn))
 608                         ifmsh->sn = target_sn;
 609
 610                 if (time_after(jiffies, ifmsh->last_sn_update +
 611                                         net_traversal_jiffies(sdata)) ||
 612                     time_before(jiffies, ifmsh->last_sn_update)) {
 613                         ++ifmsh->sn;
 614                         ifmsh->last_sn_update = jiffies;
 615                 }
 616                 target_sn = ifmsh->sn;
 617         } else if (is_broadcast_ether_addr(target_addr) &&
 618                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 619                 rcu_read_lock();
 620                 mpath = mesh_path_lookup(sdata, orig_addr);
 621                 if (mpath) {
 622                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 623                                 reply = true;
 624                                 target_addr = sdata->vif.addr;
 625                                 target_sn = ++ifmsh->sn;
 626                                 target_metric = 0;
 627                                 ifmsh->last_sn_update = jiffies;
 628                         }
 629                         if (root_is_gate)
 630                                 mesh_path_add_gate(mpath);
 631                 }
 632                 rcu_read_unlock();
 633         } else {
 634                 rcu_read_lock();
 635                 mpath = mesh_path_lookup(sdata, target_addr);
 636                 if (mpath) {
 637                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 638                                         SN_LT(mpath->sn, target_sn)) {
 639                                 mpath->sn = target_sn;
 640                                 mpath->flags |= MESH_PATH_SN_VALID;
 641                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 642                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 643                                 reply = true;
 644                                 target_metric = mpath->metric;
 645                                 target_sn = mpath->sn;
 646                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 647                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 648                         }
 649                 }
 650                 rcu_read_unlock();
 651         }
 652
 653         if (reply) {
 654                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 655                 ttl = ifmsh->mshcfg.element_ttl;
 656                 if (ttl != 0) {
 657                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 658                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 659                                                orig_sn, 0, target_addr,
 660                                                target_sn, mgmt->sa, 0, ttl,
 661                                                lifetime, target_metric, 0,
 662                                                sdata);
 663                 } else {
 664                         ifmsh->mshstats.dropped_frames_ttl++;
 665                 }
 666         }
 667
 668         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 669                 u32 preq_id;
 670                 u8 hopcount;
 671
 672                 ttl = PREQ_IE_TTL(preq_elem);
 673                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 674                 if (ttl <= 1) {
 675                         ifmsh->mshstats.dropped_frames_ttl++;
 676                         return;
 677                 }
 678                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 679                 --ttl;
 680                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 681                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 682                 da = (mpath && mpath->is_root) ?
 683                         mpath->rann_snd_addr : broadcast_addr;
 684
 685                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 686                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 687                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 688                 }
 689
 690                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 691                                        orig_sn, target_flags, target_addr,
 692                                        target_sn, da, hopcount, ttl, lifetime,
 693                                        orig_metric, preq_id, sdata);
 694                 if (!is_multicast_ether_addr(da))
 695                         ifmsh->mshstats.fwded_unicast++;
 696                 else
 697                         ifmsh->mshstats.fwded_mcast++;
 698                 ifmsh->mshstats.fwded_frames++;
 699         }
 700 }
 701
 702
 703 static inline struct sta_info *
 704 next_hop_deref_protected(struct mesh_path *mpath)
 705 {
 706         return rcu_dereference_protected(mpath->next_hop,
 707                                          lockdep_is_held(&mpath->state_lock));
 708 }
 709
 710
 711 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 712                                     struct ieee80211_mgmt *mgmt,
 713                                     const u8 *prep_elem, u32 metric)
 714 {
 715         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 716         struct mesh_path *mpath;
 717         const u8 *target_addr, *orig_addr;
 718         u8 ttl, hopcount, flags;
 719         u8 next_hop[ETH_ALEN];
 720         u32 target_sn, orig_sn, lifetime;
 721
 722         mhwmp_dbg(sdata, "received PREP from %pM\n",
 723                   PREP_IE_TARGET_ADDR(prep_elem));
 724
 725         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 726         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 727                 /* destination, no forwarding required */
 728                 return;
 729
 730         if (!ifmsh->mshcfg.dot11MeshForwarding)
 731                 return;
 732
 733         ttl = PREP_IE_TTL(prep_elem);
 734         if (ttl <= 1) {
 735                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 736                 return;
 737         }
 738
 739         rcu_read_lock();
 740         mpath = mesh_path_lookup(sdata, orig_addr);
 741         if (mpath)
 742                 spin_lock_bh(&mpath->state_lock);
 743         else
 744                 goto fail;
 745         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 746                 spin_unlock_bh(&mpath->state_lock);
 747                 goto fail;
 748         }
 749         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 750         spin_unlock_bh(&mpath->state_lock);
 751         --ttl;
 752         flags = PREP_IE_FLAGS(prep_elem);
 753         lifetime = PREP_IE_LIFETIME(prep_elem);
 754         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 755         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 756         target_sn = PREP_IE_TARGET_SN(prep_elem);
 757         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 758
 759         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 760                                target_addr, target_sn, next_hop, hopcount,
 761                                ttl, lifetime, metric, 0, sdata);
 762         rcu_read_unlock();
 763
 764         sdata->u.mesh.mshstats.fwded_unicast++;
 765         sdata->u.mesh.mshstats.fwded_frames++;
 766         return;
 767
 768 fail:
 769         rcu_read_unlock();
 770         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 771 }
 772
 773 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 774                                     struct ieee80211_mgmt *mgmt,
 775                                     const u8 *perr_elem)
 776 {
 777         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 778         struct mesh_path *mpath;
 779         u8 ttl;
 780         const u8 *ta, *target_addr;
 781         u32 target_sn;
 782         u16 target_rcode;
 783
 784         ta = mgmt->sa;
 785         ttl = PERR_IE_TTL(perr_elem);
 786         if (ttl <= 1) {
 787                 ifmsh->mshstats.dropped_frames_ttl++;
 788                 return;
 789         }
 790         ttl--;
 791         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 792         target_sn = PERR_IE_TARGET_SN(perr_elem);
 793         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 794
 795         rcu_read_lock();
 796         mpath = mesh_path_lookup(sdata, target_addr);
 797         if (mpath) {
 798                 struct sta_info *sta;
 799
 800                 spin_lock_bh(&mpath->state_lock);
 801                 sta = next_hop_deref_protected(mpath);
 802                 if (mpath->flags & MESH_PATH_ACTIVE &&
 803                     ether_addr_equal(ta, sta->sta.addr) &&
 804                     !(mpath->flags & MESH_PATH_FIXED) &&
 805                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 806                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 807                         mpath->flags &= ~MESH_PATH_ACTIVE;
 808                         if (target_sn != 0)
 809                                 mpath->sn = target_sn;
 810                         else
 811                                 mpath->sn += 1;
 812                         spin_unlock_bh(&mpath->state_lock);
 813                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 814                                 goto endperr;
 815                         mesh_path_error_tx(sdata, ttl, target_addr,
 816                                            target_sn, target_rcode,
 817                                            broadcast_addr);
 818                 } else
 819                         spin_unlock_bh(&mpath->state_lock);
 820         }
 821 endperr:
 822         rcu_read_unlock();
 823 }
 824
 825 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 826                                     struct ieee80211_mgmt *mgmt,
 827                                     const struct ieee80211_rann_ie *rann)
 828 {
 829         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 830         struct ieee80211_local *local = sdata->local;
 831         struct sta_info *sta;
 832         struct mesh_path *mpath;
 833         u8 ttl, flags, hopcount;
 834         const u8 *orig_addr;
 835         u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
 836         bool root_is_gate;
 837
 838         ttl = rann->rann_ttl;
 839         flags = rann->rann_flags;
 840         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 841         orig_addr = rann->rann_addr;
 842         orig_sn = le32_to_cpu(rann->rann_seq);
 843         interval = le32_to_cpu(rann->rann_interval);
 844         hopcount = rann->rann_hopcount;
 845         hopcount++;
 846         orig_metric = le32_to_cpu(rann->rann_metric);
 847
 848         /*  Ignore our own RANNs */
 849         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 850                 return;
 851
 852         mhwmp_dbg(sdata,
 853                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 854                   orig_addr, mgmt->sa, root_is_gate);
 855
 856         rcu_read_lock();
 857         sta = sta_info_get(sdata, mgmt->sa);
 858         if (!sta) {
 859                 rcu_read_unlock();
 860                 return;
 861         }
 862
 863         last_hop_metric = airtime_link_metric_get(local, sta);
 864         new_metric = orig_metric + last_hop_metric;
 865         if (new_metric < orig_metric)
 866                 new_metric = MAX_METRIC;
 867
 868         mpath = mesh_path_lookup(sdata, orig_addr);
 869         if (!mpath) {
 870                 mpath = mesh_path_add(sdata, orig_addr);
 871                 if (IS_ERR(mpath)) {
 872                         rcu_read_unlock();
 873                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 874                         return;
 875                 }
 876         }
 877
 878         if (!(SN_LT(mpath->sn, orig_sn)) &&
 879             !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
 880                 rcu_read_unlock();
 881                 return;
 882         }
 883
 884         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 885              (time_after(jiffies, mpath->last_preq_to_root +
 886                                   root_path_confirmation_jiffies(sdata)) ||
 887              time_before(jiffies, mpath->last_preq_to_root))) &&
 888              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 889                 mhwmp_dbg(sdata,
 890                           "time to refresh root mpath %pM\n",
 891                           orig_addr);
 892                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 893                 mpath->last_preq_to_root = jiffies;
 894         }
 895
 896         mpath->sn = orig_sn;
 897         mpath->rann_metric = new_metric;
 898         mpath->is_root = true;
 899         /* Recording RANNs sender address to send individually
 900          * addressed PREQs destined for root mesh STA */
 901         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 902
 903         if (root_is_gate)
 904                 mesh_path_add_gate(mpath);
 905
 906         if (ttl <= 1) {
 907                 ifmsh->mshstats.dropped_frames_ttl++;
 908                 rcu_read_unlock();
 909                 return;
 910         }
 911         ttl--;
 912
 913         if (ifmsh->mshcfg.dot11MeshForwarding) {
 914                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 915                                        orig_sn, 0, NULL, 0, broadcast_addr,
 916                                        hopcount, ttl, interval,
 917                                        new_metric, 0, sdata);
 918         }
 919
 920         rcu_read_unlock();
 921 }
 922
 923
 924 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 925                             struct ieee80211_mgmt *mgmt, size_t len)
 926 {
 927         struct ieee802_11_elems *elems;
 928         size_t baselen;
 929         u32 path_metric;
 930         struct sta_info *sta;
 931
 932         /* need action_code */
 933         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 934                 return;
 935
 936         rcu_read_lock();
 937         sta = sta_info_get(sdata, mgmt->sa);
 938         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 939                 rcu_read_unlock();
 940                 return;
 941         }
 942         rcu_read_unlock();
 943
 944         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 945         elems = ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 946                                        len - baselen, false, NULL);
 947         if (!elems)
 948                 return;
 949
 950         if (elems->preq) {
 951                 if (elems->preq_len != 37)
 952                         /* Right now we support just 1 destination and no AE */
 953                         goto free;
 954                 path_metric = hwmp_route_info_get(sdata, mgmt, elems->preq,
 955                                                   MPATH_PREQ);
 956                 if (path_metric)
 957                         hwmp_preq_frame_process(sdata, mgmt, elems->preq,
 958                                                 path_metric);
 959         }
 960         if (elems->prep) {
 961                 if (elems->prep_len != 31)
 962                         /* Right now we support no AE */
 963                         goto free;
 964                 path_metric = hwmp_route_info_get(sdata, mgmt, elems->prep,
 965                                                   MPATH_PREP);
 966                 if (path_metric)
 967                         hwmp_prep_frame_process(sdata, mgmt, elems->prep,
 968                                                 path_metric);
 969         }
 970         if (elems->perr) {
 971                 if (elems->perr_len != 15)
 972                         /* Right now we support only one destination per PERR */
 973                         goto free;
 974                 hwmp_perr_frame_process(sdata, mgmt, elems->perr);
 975         }
 976         if (elems->rann)
 977                 hwmp_rann_frame_process(sdata, mgmt, elems->rann);
 978 free:
 979         kfree(elems);
 980 }
 981
 982 /**
 983  * mesh_queue_preq - queue a PREQ to a given destination
 984  *
 985  * @mpath: mesh path to discover
 986  * @flags: special attributes of the PREQ to be sent
 987  *
 988  * Locking: the function must be called from within a rcu read lock block.
 989  *
 990  */
 991 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 992 {
 993         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 994         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 995         struct mesh_preq_queue *preq_node;
 996
 997         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 998         if (!preq_node) {
 999                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
1000                 return;
1001         }
1002
1003         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1004         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
1005                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1006                 kfree(preq_node);
1007                 if (printk_ratelimit())
1008                         mhwmp_dbg(sdata, "PREQ node queue full\n");
1009                 return;
1010         }
1011
1012         spin_lock(&mpath->state_lock);
1013         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
1014                 spin_unlock(&mpath->state_lock);
1015                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1016                 kfree(preq_node);
1017                 return;
1018         }
1019
1020         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
1021         preq_node->flags = flags;
1022
1023         mpath->flags |= MESH_PATH_REQ_QUEUED;
1024         spin_unlock(&mpath->state_lock);
1025
1026         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
1027         ++ifmsh->preq_queue_len;
1028         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1029
1030         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
1031                 wiphy_work_queue(sdata->local->hw.wiphy, &sdata->work);
1032
1033         else if (time_before(jiffies, ifmsh->last_preq)) {
1034                 /* avoid long wait if did not send preqs for a long time
1035                  * and jiffies wrapped around
1036                  */
1037                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1038                 wiphy_work_queue(sdata->local->hw.wiphy, &sdata->work);
1039         } else
1040                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1041                                                 min_preq_int_jiff(sdata));
1042 }
1043
1044 /**
1045  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1046  *
1047  * @sdata: local mesh subif
1048  */
1049 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1050 {
1051         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1052         struct mesh_preq_queue *preq_node;
1053         struct mesh_path *mpath;
1054         u8 ttl, target_flags = 0;
1055         const u8 *da;
1056         u32 lifetime;
1057
1058         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1059         if (!ifmsh->preq_queue_len ||
1060                 time_before(jiffies, ifmsh->last_preq +
1061                                 min_preq_int_jiff(sdata))) {
1062                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1063                 return;
1064         }
1065
1066         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1067                         struct mesh_preq_queue, list);
1068         list_del(&preq_node->list);
1069         --ifmsh->preq_queue_len;
1070         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1071
1072         rcu_read_lock();
1073         mpath = mesh_path_lookup(sdata, preq_node->dst);
1074         if (!mpath)
1075                 goto enddiscovery;
1076
1077         spin_lock_bh(&mpath->state_lock);
1078         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1079                 spin_unlock_bh(&mpath->state_lock);
1080                 goto enddiscovery;
1081         }
1082         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1083         if (preq_node->flags & PREQ_Q_F_START) {
1084                 if (mpath->flags & MESH_PATH_RESOLVING) {
1085                         spin_unlock_bh(&mpath->state_lock);
1086                         goto enddiscovery;
1087                 } else {
1088                         mpath->flags &= ~MESH_PATH_RESOLVED;
1089                         mpath->flags |= MESH_PATH_RESOLVING;
1090                         mpath->discovery_retries = 0;
1091                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1092                 }
1093         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1094                         mpath->flags & MESH_PATH_RESOLVED) {
1095                 mpath->flags &= ~MESH_PATH_RESOLVING;
1096                 spin_unlock_bh(&mpath->state_lock);
1097                 goto enddiscovery;
1098         }
1099
1100         ifmsh->last_preq = jiffies;
1101
1102         if (time_after(jiffies, ifmsh->last_sn_update +
1103                                 net_traversal_jiffies(sdata)) ||
1104             time_before(jiffies, ifmsh->last_sn_update)) {
1105                 ++ifmsh->sn;
1106                 sdata->u.mesh.last_sn_update = jiffies;
1107         }
1108         lifetime = default_lifetime(sdata);
1109         ttl = sdata->u.mesh.mshcfg.element_ttl;
1110         if (ttl == 0) {
1111                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1112                 spin_unlock_bh(&mpath->state_lock);
1113                 goto enddiscovery;
1114         }
1115
1116         if (preq_node->flags & PREQ_Q_F_REFRESH)
1117                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1118         else
1119                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1120
1121         spin_unlock_bh(&mpath->state_lock);
1122         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1123         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1124                                target_flags, mpath->dst, mpath->sn, da, 0,
1125                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1126
1127         spin_lock_bh(&mpath->state_lock);
1128         if (!(mpath->flags & MESH_PATH_DELETED))
1129                 mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1130         spin_unlock_bh(&mpath->state_lock);
1131
1132 enddiscovery:
1133         rcu_read_unlock();
1134         kfree(preq_node);
1135 }
1136
1137 /**
1138  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1139  *
1140  * @skb: 802.11 frame to be sent
1141  * @sdata: network subif the frame will be sent through
1142  *
1143  * Lookup next hop for given skb and start path discovery if no
1144  * forwarding information is found.
1145  *
1146  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1147  * skb is freed here if no mpath could be allocated.
1148  */
1149 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1150                          struct sk_buff *skb)
1151 {
1152         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1153         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1154         struct mesh_path *mpath;
1155         struct sk_buff *skb_to_free = NULL;
1156         u8 *target_addr = hdr->addr3;
1157
1158         /* Nulls are only sent to peers for PS and should be pre-addressed */
1159         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1160                 return 0;
1161
1162         /* Allow injected packets to bypass mesh routing */
1163         if (info->control.flags & IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP)
1164                 return 0;
1165
1166         if (!mesh_nexthop_lookup(sdata, skb))
1167                 return 0;
1168
1169         /* no nexthop found, start resolving */
1170         mpath = mesh_path_lookup(sdata, target_addr);
1171         if (!mpath) {
1172                 mpath = mesh_path_add(sdata, target_addr);
1173                 if (IS_ERR(mpath)) {
1174                         mesh_path_discard_frame(sdata, skb);
1175                         return PTR_ERR(mpath);
1176                 }
1177         }
1178
1179         if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1180             mesh_path_sel_is_hwmp(sdata))
1181                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1182
1183         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1184                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1185
1186         info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
1187         ieee80211_set_qos_hdr(sdata, skb);
1188         skb_queue_tail(&mpath->frame_queue, skb);
1189         if (skb_to_free)
1190                 mesh_path_discard_frame(sdata, skb_to_free);
1191
1192         return -ENOENT;
1193 }
1194
1195 /**
1196  * mesh_nexthop_lookup_nolearn - try to set next hop without path discovery
1197  * @skb: 802.11 frame to be sent
1198  * @sdata: network subif the frame will be sent through
1199  *
1200  * Check if the meshDA (addr3) of a unicast frame is a direct neighbor.
1201  * And if so, set the RA (addr1) to it to transmit to this node directly,
1202  * avoiding PREQ/PREP path discovery.
1203  *
1204  * Returns: 0 if the next hop was found and -ENOENT otherwise.
1205  */
1206 static int mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data *sdata,
1207                                        struct sk_buff *skb)
1208 {
1209         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1210         struct sta_info *sta;
1211
1212         if (is_multicast_ether_addr(hdr->addr1))
1213                 return -ENOENT;
1214
1215         rcu_read_lock();
1216         sta = sta_info_get(sdata, hdr->addr3);
1217
1218         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
1219                 rcu_read_unlock();
1220                 return -ENOENT;
1221         }
1222         rcu_read_unlock();
1223
1224         memcpy(hdr->addr1, hdr->addr3, ETH_ALEN);
1225         memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1226         return 0;
1227 }
1228
1229 void mesh_path_refresh(struct ieee80211_sub_if_data *sdata,
1230                        struct mesh_path *mpath, const u8 *addr)
1231 {
1232         if (mpath->flags & (MESH_PATH_REQ_QUEUED | MESH_PATH_FIXED |
1233                             MESH_PATH_RESOLVING))
1234                 return;
1235
1236         if (time_after(jiffies,
1237                        mpath->exp_time -
1238                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1239             (!addr || ether_addr_equal(sdata->vif.addr, addr)))
1240                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1241 }
1242
1243 /**
1244  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1245  * this function is considered "using" the associated mpath, so preempt a path
1246  * refresh if this mpath expires soon.
1247  *
1248  * @skb: 802.11 frame to be sent
1249  * @sdata: network subif the frame will be sent through
1250  *
1251  * Returns: 0 if the next hop was found. Nonzero otherwise.
1252  */
1253 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1254                         struct sk_buff *skb)
1255 {
1256         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1257         struct mesh_path *mpath;
1258         struct sta_info *next_hop;
1259         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1260         u8 *target_addr = hdr->addr3;
1261
1262         if (ifmsh->mshcfg.dot11MeshNolearn &&
1263             !mesh_nexthop_lookup_nolearn(sdata, skb))
1264                 return 0;
1265
1266         mpath = mesh_path_lookup(sdata, target_addr);
1267         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1268                 return -ENOENT;
1269
1270         mesh_path_refresh(sdata, mpath, hdr->addr4);
1271
1272         next_hop = rcu_dereference(mpath->next_hop);
1273         if (next_hop) {
1274                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1275                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1276                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1277                 if (ieee80211_hw_check(&sdata->local->hw, SUPPORT_FAST_XMIT))
1278                         mesh_fast_tx_cache(sdata, skb, mpath);
1279                 return 0;
1280         }
1281
1282         return -ENOENT;
1283 }
1284
1285 void mesh_path_timer(struct timer_list *t)
1286 {
1287         struct mesh_path *mpath = from_timer(mpath, t, timer);
1288         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1289         int ret;
1290
1291         if (sdata->local->quiescing)
1292                 return;
1293
1294         spin_lock_bh(&mpath->state_lock);
1295         if (mpath->flags & MESH_PATH_RESOLVED ||
1296                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1297                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1298                 spin_unlock_bh(&mpath->state_lock);
1299         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1300                 ++mpath->discovery_retries;
1301                 mpath->discovery_timeout *= 2;
1302                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1303                 spin_unlock_bh(&mpath->state_lock);
1304                 mesh_queue_preq(mpath, 0);
1305         } else {
1306                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1307                                   MESH_PATH_RESOLVED |
1308                                   MESH_PATH_REQ_QUEUED);
1309                 mpath->exp_time = jiffies;
1310                 spin_unlock_bh(&mpath->state_lock);
1311                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1312                         ret = mesh_path_send_to_gates(mpath);
1313                         if (ret)
1314                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1315                 } else
1316                         mesh_path_flush_pending(mpath);
1317         }
1318 }
1319
1320 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1321 {
1322         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1323         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1324         u8 flags, target_flags = 0;
1325
1326         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1327                         ? RANN_FLAG_IS_GATE : 0;
1328
1329         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1330         case IEEE80211_PROACTIVE_RANN:
1331                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1332                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1333                                        0, ifmsh->mshcfg.element_ttl,
1334                                        interval, 0, 0, sdata);
1335                 break;
1336         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1337                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1338                 fallthrough;
1339         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1340                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1341                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1342                                 IEEE80211_PREQ_USN_FLAG;
1343                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1344                                        ++ifmsh->sn, target_flags,
1345                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1346                                        0, ifmsh->mshcfg.element_ttl, interval,
1347                                        0, ifmsh->preq_id++, sdata);
1348                 break;
1349         default:
1350                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1351                 return;
1352         }
1353 }