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 <linux/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  * @sdata: local mesh subif
 224  * @ttl: allowed remaining hops
 225  * @target: broken destination
 226  * @target_sn: SN of the broken destination
 227  * @target_rcode: reason code for this PERR
 228  * @ra: node this frame is addressed to
 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 /* Check that the first metric is at least 10% better than the second one */
 371 static bool is_metric_better(u32 x, u32 y)
 372 {
 373         return (x < y) && (x < (y - x / 10));
 374 }
 375
 376 /**
 377  * hwmp_route_info_get - Update routing info to originator and transmitter
 378  *
 379  * @sdata: local mesh subif
 380  * @mgmt: mesh management frame
 381  * @hwmp_ie: hwmp information element (PREP or PREQ)
 382  * @action: type of hwmp ie
 383  *
 384  * This function updates the path routing information to the originator and the
 385  * transmitter of a HWMP PREQ or PREP frame.
 386  *
 387  * Returns: metric to frame originator or 0 if the frame should not be further
 388  * processed
 389  *
 390  * Notes: this function is the only place (besides user-provided info) where
 391  * path routing information is updated.
 392  */
 393 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 394                                struct ieee80211_mgmt *mgmt,
 395                                const u8 *hwmp_ie, enum mpath_frame_type action)
 396 {
 397         struct ieee80211_local *local = sdata->local;
 398         struct mesh_path *mpath;
 399         struct sta_info *sta;
 400         bool fresh_info;
 401         const u8 *orig_addr, *ta;
 402         u32 orig_sn, orig_metric;
 403         unsigned long orig_lifetime, exp_time;
 404         u32 last_hop_metric, new_metric;
 405         bool flush_mpath = false;
 406         bool process = true;
 407         u8 hopcount;
 408
 409         rcu_read_lock();
 410         sta = sta_info_get(sdata, mgmt->sa);
 411         if (!sta) {
 412                 rcu_read_unlock();
 413                 return 0;
 414         }
 415
 416         last_hop_metric = airtime_link_metric_get(local, sta);
 417         /* Update and check originator routing info */
 418         fresh_info = true;
 419
 420         switch (action) {
 421         case MPATH_PREQ:
 422                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 423                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 424                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 425                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 426                 hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1;
 427                 break;
 428         case MPATH_PREP:
 429                 /* Originator here refers to the MP that was the target in the
 430                  * Path Request. We divert from the nomenclature in the draft
 431                  * so that we can easily use a single function to gather path
 432                  * information from both PREQ and PREP frames.
 433                  */
 434                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 435                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 436                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 437                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 438                 hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1;
 439                 break;
 440         default:
 441                 rcu_read_unlock();
 442                 return 0;
 443         }
 444         new_metric = orig_metric + last_hop_metric;
 445         if (new_metric < orig_metric)
 446                 new_metric = MAX_METRIC;
 447         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 448
 449         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 450                 /* This MP is the originator, we are not interested in this
 451                  * frame, except for updating transmitter's path info.
 452                  */
 453                 process = false;
 454                 fresh_info = false;
 455         } else {
 456                 mpath = mesh_path_lookup(sdata, orig_addr);
 457                 if (mpath) {
 458                         spin_lock_bh(&mpath->state_lock);
 459                         if (mpath->flags & MESH_PATH_FIXED)
 460                                 fresh_info = false;
 461                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 462                             (mpath->flags & MESH_PATH_SN_VALID)) {
 463                                 if (SN_GT(mpath->sn, orig_sn) ||
 464                                     (mpath->sn == orig_sn &&
 465                                      (rcu_access_pointer(mpath->next_hop) !=
 466                                                       sta ?
 467                                               !is_metric_better(new_metric, mpath->metric) :
 468                                               new_metric >= mpath->metric))) {
 469                                         process = false;
 470                                         fresh_info = false;
 471                                 }
 472                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 473                                 bool have_sn, newer_sn, bounced;
 474
 475                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 476                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 477                                 bounced = have_sn &&
 478                                           (SN_DELTA(orig_sn, mpath->sn) >
 479                                                         MAX_SANE_SN_DELTA);
 480
 481                                 if (!have_sn || newer_sn) {
 482                                         /* if SN is newer than what we had
 483                                          * then we can take it */;
 484                                 } else if (bounced) {
 485                                         /* if SN is way different than what
 486                                          * we had then assume the other side
 487                                          * rebooted or restarted */;
 488                                 } else {
 489                                         process = false;
 490                                         fresh_info = false;
 491                                 }
 492                         }
 493                 } else {
 494                         mpath = mesh_path_add(sdata, orig_addr);
 495                         if (IS_ERR(mpath)) {
 496                                 rcu_read_unlock();
 497                                 return 0;
 498                         }
 499                         spin_lock_bh(&mpath->state_lock);
 500                 }
 501
 502                 if (fresh_info) {
 503                         if (rcu_access_pointer(mpath->next_hop) != sta) {
 504                                 mpath->path_change_count++;
 505                                 flush_mpath = true;
 506                         }
 507                         mesh_path_assign_nexthop(mpath, sta);
 508                         mpath->flags |= MESH_PATH_SN_VALID;
 509                         mpath->metric = new_metric;
 510                         mpath->sn = orig_sn;
 511                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 512                                           ?  mpath->exp_time : exp_time;
 513                         mpath->hop_count = hopcount;
 514                         mesh_path_activate(mpath);
 515                         spin_unlock_bh(&mpath->state_lock);
 516                         if (flush_mpath)
 517                                 mesh_fast_tx_flush_mpath(mpath);
 518                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 519                         /* init it at a low value - 0 start is tricky */
 520                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 521                         mesh_path_tx_pending(mpath);
 522                         /* draft says preq_id should be saved to, but there does
 523                          * not seem to be any use for it, skipping by now
 524                          */
 525                 } else
 526                         spin_unlock_bh(&mpath->state_lock);
 527         }
 528
 529         /* Update and check transmitter routing info */
 530         ta = mgmt->sa;
 531         if (ether_addr_equal(orig_addr, ta))
 532                 fresh_info = false;
 533         else {
 534                 fresh_info = true;
 535
 536                 mpath = mesh_path_lookup(sdata, ta);
 537                 if (mpath) {
 538                         spin_lock_bh(&mpath->state_lock);
 539                         if ((mpath->flags & MESH_PATH_FIXED) ||
 540                             ((mpath->flags & MESH_PATH_ACTIVE) &&
 541                              ((rcu_access_pointer(mpath->next_hop) != sta ?
 542                                       !is_metric_better(last_hop_metric, mpath->metric) :
 543                                        last_hop_metric > mpath->metric))))
 544                                 fresh_info = false;
 545                 } else {
 546                         mpath = mesh_path_add(sdata, ta);
 547                         if (IS_ERR(mpath)) {
 548                                 rcu_read_unlock();
 549                                 return 0;
 550                         }
 551                         spin_lock_bh(&mpath->state_lock);
 552                 }
 553
 554                 if (fresh_info) {
 555                         if (rcu_access_pointer(mpath->next_hop) != sta) {
 556                                 mpath->path_change_count++;
 557                                 flush_mpath = true;
 558                         }
 559                         mesh_path_assign_nexthop(mpath, sta);
 560                         mpath->metric = last_hop_metric;
 561                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 562                                           ?  mpath->exp_time : exp_time;
 563                         mpath->hop_count = 1;
 564                         mesh_path_activate(mpath);
 565                         spin_unlock_bh(&mpath->state_lock);
 566                         if (flush_mpath)
 567                                 mesh_fast_tx_flush_mpath(mpath);
 568                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 569                         /* init it at a low value - 0 start is tricky */
 570                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 571                         mesh_path_tx_pending(mpath);
 572                 } else
 573                         spin_unlock_bh(&mpath->state_lock);
 574         }
 575
 576         rcu_read_unlock();
 577
 578         return process ? new_metric : 0;
 579 }
 580
 581 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 582                                     struct ieee80211_mgmt *mgmt,
 583                                     const u8 *preq_elem, u32 orig_metric)
 584 {
 585         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 586         struct mesh_path *mpath = NULL;
 587         const u8 *target_addr, *orig_addr;
 588         const u8 *da;
 589         u8 target_flags, ttl, flags;
 590         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 591         bool reply = false;
 592         bool forward = true;
 593         bool root_is_gate;
 594
 595         /* Update target SN, if present */
 596         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 597         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 598         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 599         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 600         target_flags = PREQ_IE_TARGET_F(preq_elem);
 601         /* Proactive PREQ gate announcements */
 602         flags = PREQ_IE_FLAGS(preq_elem);
 603         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 604
 605         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 606
 607         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 608                 mhwmp_dbg(sdata, "PREQ is for us\n");
 609                 forward = false;
 610                 reply = true;
 611                 target_metric = 0;
 612
 613                 if (SN_GT(target_sn, ifmsh->sn))
 614                         ifmsh->sn = target_sn;
 615
 616                 if (time_after(jiffies, ifmsh->last_sn_update +
 617                                         net_traversal_jiffies(sdata)) ||
 618                     time_before(jiffies, ifmsh->last_sn_update)) {
 619                         ++ifmsh->sn;
 620                         ifmsh->last_sn_update = jiffies;
 621                 }
 622                 target_sn = ifmsh->sn;
 623         } else if (is_broadcast_ether_addr(target_addr) &&
 624                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 625                 rcu_read_lock();
 626                 mpath = mesh_path_lookup(sdata, orig_addr);
 627                 if (mpath) {
 628                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 629                                 reply = true;
 630                                 target_addr = sdata->vif.addr;
 631                                 target_sn = ++ifmsh->sn;
 632                                 target_metric = 0;
 633                                 ifmsh->last_sn_update = jiffies;
 634                         }
 635                         if (root_is_gate)
 636                                 mesh_path_add_gate(mpath);
 637                 }
 638                 rcu_read_unlock();
 639         } else if (ifmsh->mshcfg.dot11MeshForwarding) {
 640                 rcu_read_lock();
 641                 mpath = mesh_path_lookup(sdata, target_addr);
 642                 if (mpath) {
 643                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 644                                         SN_LT(mpath->sn, target_sn)) {
 645                                 mpath->sn = target_sn;
 646                                 mpath->flags |= MESH_PATH_SN_VALID;
 647                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 648                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 649                                 reply = true;
 650                                 target_metric = mpath->metric;
 651                                 target_sn = mpath->sn;
 652                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 653                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 654                         }
 655                 }
 656                 rcu_read_unlock();
 657         } else {
 658                 forward = false;
 659         }
 660
 661         if (reply) {
 662                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 663                 ttl = ifmsh->mshcfg.element_ttl;
 664                 if (ttl != 0) {
 665                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 666                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 667                                                orig_sn, 0, target_addr,
 668                                                target_sn, mgmt->sa, 0, ttl,
 669                                                lifetime, target_metric, 0,
 670                                                sdata);
 671                 } else {
 672                         ifmsh->mshstats.dropped_frames_ttl++;
 673                 }
 674         }
 675
 676         if (forward) {
 677                 u32 preq_id;
 678                 u8 hopcount;
 679
 680                 ttl = PREQ_IE_TTL(preq_elem);
 681                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 682                 if (ttl <= 1) {
 683                         ifmsh->mshstats.dropped_frames_ttl++;
 684                         return;
 685                 }
 686                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 687                 --ttl;
 688                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 689                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 690                 da = (mpath && mpath->is_root) ?
 691                         mpath->rann_snd_addr : broadcast_addr;
 692
 693                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 694                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 695                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 696                 }
 697
 698                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 699                                        orig_sn, target_flags, target_addr,
 700                                        target_sn, da, hopcount, ttl, lifetime,
 701                                        orig_metric, preq_id, sdata);
 702                 if (!is_multicast_ether_addr(da))
 703                         ifmsh->mshstats.fwded_unicast++;
 704                 else
 705                         ifmsh->mshstats.fwded_mcast++;
 706                 ifmsh->mshstats.fwded_frames++;
 707         }
 708 }
 709
 710
 711 static inline struct sta_info *
 712 next_hop_deref_protected(struct mesh_path *mpath)
 713 {
 714         return rcu_dereference_protected(mpath->next_hop,
 715                                          lockdep_is_held(&mpath->state_lock));
 716 }
 717
 718
 719 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 720                                     struct ieee80211_mgmt *mgmt,
 721                                     const u8 *prep_elem, u32 metric)
 722 {
 723         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 724         struct mesh_path *mpath;
 725         const u8 *target_addr, *orig_addr;
 726         u8 ttl, hopcount, flags;
 727         u8 next_hop[ETH_ALEN];
 728         u32 target_sn, orig_sn, lifetime;
 729
 730         mhwmp_dbg(sdata, "received PREP from %pM\n",
 731                   PREP_IE_TARGET_ADDR(prep_elem));
 732
 733         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 734         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 735                 /* destination, no forwarding required */
 736                 return;
 737
 738         if (!ifmsh->mshcfg.dot11MeshForwarding)
 739                 return;
 740
 741         ttl = PREP_IE_TTL(prep_elem);
 742         if (ttl <= 1) {
 743                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 744                 return;
 745         }
 746
 747         rcu_read_lock();
 748         mpath = mesh_path_lookup(sdata, orig_addr);
 749         if (mpath)
 750                 spin_lock_bh(&mpath->state_lock);
 751         else
 752                 goto fail;
 753         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 754                 spin_unlock_bh(&mpath->state_lock);
 755                 goto fail;
 756         }
 757         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 758         spin_unlock_bh(&mpath->state_lock);
 759         --ttl;
 760         flags = PREP_IE_FLAGS(prep_elem);
 761         lifetime = PREP_IE_LIFETIME(prep_elem);
 762         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 763         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 764         target_sn = PREP_IE_TARGET_SN(prep_elem);
 765         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 766
 767         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 768                                target_addr, target_sn, next_hop, hopcount,
 769                                ttl, lifetime, metric, 0, sdata);
 770         rcu_read_unlock();
 771
 772         sdata->u.mesh.mshstats.fwded_unicast++;
 773         sdata->u.mesh.mshstats.fwded_frames++;
 774         return;
 775
 776 fail:
 777         rcu_read_unlock();
 778         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 779 }
 780
 781 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 782                                     struct ieee80211_mgmt *mgmt,
 783                                     const u8 *perr_elem)
 784 {
 785         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 786         struct mesh_path *mpath;
 787         u8 ttl;
 788         const u8 *ta, *target_addr;
 789         u32 target_sn;
 790         u16 target_rcode;
 791
 792         ta = mgmt->sa;
 793         ttl = PERR_IE_TTL(perr_elem);
 794         if (ttl <= 1) {
 795                 ifmsh->mshstats.dropped_frames_ttl++;
 796                 return;
 797         }
 798         ttl--;
 799         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 800         target_sn = PERR_IE_TARGET_SN(perr_elem);
 801         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 802
 803         rcu_read_lock();
 804         mpath = mesh_path_lookup(sdata, target_addr);
 805         if (mpath) {
 806                 struct sta_info *sta;
 807
 808                 spin_lock_bh(&mpath->state_lock);
 809                 sta = next_hop_deref_protected(mpath);
 810                 if (mpath->flags & MESH_PATH_ACTIVE &&
 811                     ether_addr_equal(ta, sta->sta.addr) &&
 812                     !(mpath->flags & MESH_PATH_FIXED) &&
 813                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 814                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 815                         mpath->flags &= ~MESH_PATH_ACTIVE;
 816                         if (target_sn != 0)
 817                                 mpath->sn = target_sn;
 818                         else
 819                                 mpath->sn += 1;
 820                         spin_unlock_bh(&mpath->state_lock);
 821                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 822                                 goto endperr;
 823                         mesh_path_error_tx(sdata, ttl, target_addr,
 824                                            target_sn, target_rcode,
 825                                            broadcast_addr);
 826                 } else
 827                         spin_unlock_bh(&mpath->state_lock);
 828         }
 829 endperr:
 830         rcu_read_unlock();
 831 }
 832
 833 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 834                                     struct ieee80211_mgmt *mgmt,
 835                                     const struct ieee80211_rann_ie *rann)
 836 {
 837         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 838         struct ieee80211_local *local = sdata->local;
 839         struct sta_info *sta;
 840         struct mesh_path *mpath;
 841         u8 ttl, flags, hopcount;
 842         const u8 *orig_addr;
 843         u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
 844         bool root_is_gate;
 845
 846         ttl = rann->rann_ttl;
 847         flags = rann->rann_flags;
 848         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 849         orig_addr = rann->rann_addr;
 850         orig_sn = le32_to_cpu(rann->rann_seq);
 851         interval = le32_to_cpu(rann->rann_interval);
 852         hopcount = rann->rann_hopcount;
 853         hopcount++;
 854         orig_metric = le32_to_cpu(rann->rann_metric);
 855
 856         /*  Ignore our own RANNs */
 857         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 858                 return;
 859
 860         mhwmp_dbg(sdata,
 861                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 862                   orig_addr, mgmt->sa, root_is_gate);
 863
 864         rcu_read_lock();
 865         sta = sta_info_get(sdata, mgmt->sa);
 866         if (!sta) {
 867                 rcu_read_unlock();
 868                 return;
 869         }
 870
 871         last_hop_metric = airtime_link_metric_get(local, sta);
 872         new_metric = orig_metric + last_hop_metric;
 873         if (new_metric < orig_metric)
 874                 new_metric = MAX_METRIC;
 875
 876         mpath = mesh_path_lookup(sdata, orig_addr);
 877         if (!mpath) {
 878                 mpath = mesh_path_add(sdata, orig_addr);
 879                 if (IS_ERR(mpath)) {
 880                         rcu_read_unlock();
 881                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 882                         return;
 883                 }
 884         }
 885
 886         if (!(SN_LT(mpath->sn, orig_sn)) &&
 887             !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
 888                 rcu_read_unlock();
 889                 return;
 890         }
 891
 892         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 893              (time_after(jiffies, mpath->last_preq_to_root +
 894                                   root_path_confirmation_jiffies(sdata)) ||
 895              time_before(jiffies, mpath->last_preq_to_root))) &&
 896              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 897                 mhwmp_dbg(sdata,
 898                           "time to refresh root mpath %pM\n",
 899                           orig_addr);
 900                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 901                 mpath->last_preq_to_root = jiffies;
 902         }
 903
 904         mpath->sn = orig_sn;
 905         mpath->rann_metric = new_metric;
 906         mpath->is_root = true;
 907         /* Recording RANNs sender address to send individually
 908          * addressed PREQs destined for root mesh STA */
 909         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 910
 911         if (root_is_gate)
 912                 mesh_path_add_gate(mpath);
 913
 914         if (ttl <= 1) {
 915                 ifmsh->mshstats.dropped_frames_ttl++;
 916                 rcu_read_unlock();
 917                 return;
 918         }
 919         ttl--;
 920
 921         if (ifmsh->mshcfg.dot11MeshForwarding) {
 922                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 923                                        orig_sn, 0, NULL, 0, broadcast_addr,
 924                                        hopcount, ttl, interval,
 925                                        new_metric, 0, sdata);
 926         }
 927
 928         rcu_read_unlock();
 929 }
 930
 931
 932 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 933                             struct ieee80211_mgmt *mgmt, size_t len)
 934 {
 935         struct ieee802_11_elems *elems;
 936         size_t baselen;
 937         u32 path_metric;
 938         struct sta_info *sta;
 939
 940         /* need action_code */
 941         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 942                 return;
 943
 944         rcu_read_lock();
 945         sta = sta_info_get(sdata, mgmt->sa);
 946         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 947                 rcu_read_unlock();
 948                 return;
 949         }
 950         rcu_read_unlock();
 951
 952         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 953         elems = ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 954                                        len - baselen, false, NULL);
 955         if (!elems)
 956                 return;
 957
 958         if (elems->preq) {
 959                 if (elems->preq_len != 37)
 960                         /* Right now we support just 1 destination and no AE */
 961                         goto free;
 962                 path_metric = hwmp_route_info_get(sdata, mgmt, elems->preq,
 963                                                   MPATH_PREQ);
 964                 if (path_metric)
 965                         hwmp_preq_frame_process(sdata, mgmt, elems->preq,
 966                                                 path_metric);
 967         }
 968         if (elems->prep) {
 969                 if (elems->prep_len != 31)
 970                         /* Right now we support no AE */
 971                         goto free;
 972                 path_metric = hwmp_route_info_get(sdata, mgmt, elems->prep,
 973                                                   MPATH_PREP);
 974                 if (path_metric)
 975                         hwmp_prep_frame_process(sdata, mgmt, elems->prep,
 976                                                 path_metric);
 977         }
 978         if (elems->perr) {
 979                 if (elems->perr_len != 15)
 980                         /* Right now we support only one destination per PERR */
 981                         goto free;
 982                 hwmp_perr_frame_process(sdata, mgmt, elems->perr);
 983         }
 984         if (elems->rann)
 985                 hwmp_rann_frame_process(sdata, mgmt, elems->rann);
 986 free:
 987         kfree(elems);
 988 }
 989
 990 /**
 991  * mesh_queue_preq - queue a PREQ to a given destination
 992  *
 993  * @mpath: mesh path to discover
 994  * @flags: special attributes of the PREQ to be sent
 995  *
 996  * Locking: the function must be called from within a rcu read lock block.
 997  *
 998  */
 999 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
1000 {
1001         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1002         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1003         struct mesh_preq_queue *preq_node;
1004
1005         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
1006         if (!preq_node) {
1007                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
1008                 return;
1009         }
1010
1011         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1012         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
1013                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1014                 kfree(preq_node);
1015                 if (printk_ratelimit())
1016                         mhwmp_dbg(sdata, "PREQ node queue full\n");
1017                 return;
1018         }
1019
1020         spin_lock(&mpath->state_lock);
1021         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
1022                 spin_unlock(&mpath->state_lock);
1023                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1024                 kfree(preq_node);
1025                 return;
1026         }
1027
1028         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
1029         preq_node->flags = flags;
1030
1031         mpath->flags |= MESH_PATH_REQ_QUEUED;
1032         spin_unlock(&mpath->state_lock);
1033
1034         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
1035         ++ifmsh->preq_queue_len;
1036         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1037
1038         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
1039                 wiphy_work_queue(sdata->local->hw.wiphy, &sdata->work);
1040
1041         else if (time_before(jiffies, ifmsh->last_preq)) {
1042                 /* avoid long wait if did not send preqs for a long time
1043                  * and jiffies wrapped around
1044                  */
1045                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1046                 wiphy_work_queue(sdata->local->hw.wiphy, &sdata->work);
1047         } else
1048                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1049                                                 min_preq_int_jiff(sdata));
1050 }
1051
1052 /**
1053  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1054  *
1055  * @sdata: local mesh subif
1056  */
1057 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1058 {
1059         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1060         struct mesh_preq_queue *preq_node;
1061         struct mesh_path *mpath;
1062         u8 ttl, target_flags = 0;
1063         const u8 *da;
1064         u32 lifetime;
1065
1066         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1067         if (!ifmsh->preq_queue_len ||
1068                 time_before(jiffies, ifmsh->last_preq +
1069                                 min_preq_int_jiff(sdata))) {
1070                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1071                 return;
1072         }
1073
1074         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1075                         struct mesh_preq_queue, list);
1076         list_del(&preq_node->list);
1077         --ifmsh->preq_queue_len;
1078         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1079
1080         rcu_read_lock();
1081         mpath = mesh_path_lookup(sdata, preq_node->dst);
1082         if (!mpath)
1083                 goto enddiscovery;
1084
1085         spin_lock_bh(&mpath->state_lock);
1086         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1087                 spin_unlock_bh(&mpath->state_lock);
1088                 goto enddiscovery;
1089         }
1090         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1091         if (preq_node->flags & PREQ_Q_F_START) {
1092                 if (mpath->flags & MESH_PATH_RESOLVING) {
1093                         spin_unlock_bh(&mpath->state_lock);
1094                         goto enddiscovery;
1095                 } else {
1096                         mpath->flags &= ~MESH_PATH_RESOLVED;
1097                         mpath->flags |= MESH_PATH_RESOLVING;
1098                         mpath->discovery_retries = 0;
1099                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1100                 }
1101         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1102                         mpath->flags & MESH_PATH_RESOLVED) {
1103                 mpath->flags &= ~MESH_PATH_RESOLVING;
1104                 spin_unlock_bh(&mpath->state_lock);
1105                 goto enddiscovery;
1106         }
1107
1108         ifmsh->last_preq = jiffies;
1109
1110         if (time_after(jiffies, ifmsh->last_sn_update +
1111                                 net_traversal_jiffies(sdata)) ||
1112             time_before(jiffies, ifmsh->last_sn_update)) {
1113                 ++ifmsh->sn;
1114                 sdata->u.mesh.last_sn_update = jiffies;
1115         }
1116         lifetime = default_lifetime(sdata);
1117         ttl = sdata->u.mesh.mshcfg.element_ttl;
1118         if (ttl == 0) {
1119                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1120                 spin_unlock_bh(&mpath->state_lock);
1121                 goto enddiscovery;
1122         }
1123
1124         if (preq_node->flags & PREQ_Q_F_REFRESH)
1125                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1126         else
1127                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1128
1129         spin_unlock_bh(&mpath->state_lock);
1130         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1131         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1132                                target_flags, mpath->dst, mpath->sn, da, 0,
1133                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1134
1135         spin_lock_bh(&mpath->state_lock);
1136         if (!(mpath->flags & MESH_PATH_DELETED))
1137                 mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1138         spin_unlock_bh(&mpath->state_lock);
1139
1140 enddiscovery:
1141         rcu_read_unlock();
1142         kfree(preq_node);
1143 }
1144
1145 /**
1146  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1147  *
1148  * @sdata: network subif the frame will be sent through
1149  * @skb: 802.11 frame to be sent
1150  *
1151  * Lookup next hop for given skb and start path discovery if no
1152  * forwarding information is found.
1153  *
1154  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1155  * skb is freed here if no mpath could be allocated.
1156  */
1157 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1158                          struct sk_buff *skb)
1159 {
1160         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1161         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1162         struct mesh_path *mpath;
1163         struct sk_buff *skb_to_free = NULL;
1164         u8 *target_addr = hdr->addr3;
1165
1166         /* Nulls are only sent to peers for PS and should be pre-addressed */
1167         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1168                 return 0;
1169
1170         /* Allow injected packets to bypass mesh routing */
1171         if (info->control.flags & IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP)
1172                 return 0;
1173
1174         if (!mesh_nexthop_lookup(sdata, skb))
1175                 return 0;
1176
1177         /* no nexthop found, start resolving */
1178         mpath = mesh_path_lookup(sdata, target_addr);
1179         if (!mpath) {
1180                 mpath = mesh_path_add(sdata, target_addr);
1181                 if (IS_ERR(mpath)) {
1182                         mesh_path_discard_frame(sdata, skb);
1183                         return PTR_ERR(mpath);
1184                 }
1185         }
1186
1187         if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1188             mesh_path_sel_is_hwmp(sdata))
1189                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1190
1191         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1192                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1193
1194         info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
1195         ieee80211_set_qos_hdr(sdata, skb);
1196         skb_queue_tail(&mpath->frame_queue, skb);
1197         if (skb_to_free)
1198                 mesh_path_discard_frame(sdata, skb_to_free);
1199
1200         return -ENOENT;
1201 }
1202
1203 /**
1204  * mesh_nexthop_lookup_nolearn - try to set next hop without path discovery
1205  * @skb: 802.11 frame to be sent
1206  * @sdata: network subif the frame will be sent through
1207  *
1208  * Check if the meshDA (addr3) of a unicast frame is a direct neighbor.
1209  * And if so, set the RA (addr1) to it to transmit to this node directly,
1210  * avoiding PREQ/PREP path discovery.
1211  *
1212  * Returns: 0 if the next hop was found and -ENOENT otherwise.
1213  */
1214 static int mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data *sdata,
1215                                        struct sk_buff *skb)
1216 {
1217         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1218         struct sta_info *sta;
1219
1220         if (is_multicast_ether_addr(hdr->addr1))
1221                 return -ENOENT;
1222
1223         rcu_read_lock();
1224         sta = sta_info_get(sdata, hdr->addr3);
1225
1226         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
1227                 rcu_read_unlock();
1228                 return -ENOENT;
1229         }
1230         rcu_read_unlock();
1231
1232         memcpy(hdr->addr1, hdr->addr3, ETH_ALEN);
1233         memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1234         return 0;
1235 }
1236
1237 void mesh_path_refresh(struct ieee80211_sub_if_data *sdata,
1238                        struct mesh_path *mpath, const u8 *addr)
1239 {
1240         if (mpath->flags & (MESH_PATH_REQ_QUEUED | MESH_PATH_FIXED |
1241                             MESH_PATH_RESOLVING))
1242                 return;
1243
1244         if (time_after(jiffies,
1245                        mpath->exp_time -
1246                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1247             (!addr || ether_addr_equal(sdata->vif.addr, addr)))
1248                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1249 }
1250
1251 /**
1252  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1253  * this function is considered "using" the associated mpath, so preempt a path
1254  * refresh if this mpath expires soon.
1255  *
1256  * @sdata: network subif the frame will be sent through
1257  * @skb: 802.11 frame to be sent
1258  *
1259  * Returns: 0 if the next hop was found. Nonzero otherwise.
1260  */
1261 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1262                         struct sk_buff *skb)
1263 {
1264         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1265         struct mesh_path *mpath;
1266         struct sta_info *next_hop;
1267         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1268         u8 *target_addr = hdr->addr3;
1269
1270         if (ifmsh->mshcfg.dot11MeshNolearn &&
1271             !mesh_nexthop_lookup_nolearn(sdata, skb))
1272                 return 0;
1273
1274         mpath = mesh_path_lookup(sdata, target_addr);
1275         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1276                 return -ENOENT;
1277
1278         mesh_path_refresh(sdata, mpath, hdr->addr4);
1279
1280         next_hop = rcu_dereference(mpath->next_hop);
1281         if (next_hop) {
1282                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1283                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1284                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1285                 if (ieee80211_hw_check(&sdata->local->hw, SUPPORT_FAST_XMIT))
1286                         mesh_fast_tx_cache(sdata, skb, mpath);
1287                 return 0;
1288         }
1289
1290         return -ENOENT;
1291 }
1292
1293 void mesh_path_timer(struct timer_list *t)
1294 {
1295         struct mesh_path *mpath = timer_container_of(mpath, t, timer);
1296         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1297         int ret;
1298
1299         if (sdata->local->quiescing)
1300                 return;
1301
1302         spin_lock_bh(&mpath->state_lock);
1303         if (mpath->flags & MESH_PATH_RESOLVED ||
1304                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1305                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1306                 spin_unlock_bh(&mpath->state_lock);
1307         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1308                 ++mpath->discovery_retries;
1309                 mpath->discovery_timeout *= 2;
1310                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1311                 spin_unlock_bh(&mpath->state_lock);
1312                 mesh_queue_preq(mpath, 0);
1313         } else {
1314                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1315                                   MESH_PATH_RESOLVED |
1316                                   MESH_PATH_REQ_QUEUED);
1317                 mpath->exp_time = jiffies;
1318                 spin_unlock_bh(&mpath->state_lock);
1319                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1320                         ret = mesh_path_send_to_gates(mpath);
1321                         if (ret)
1322                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1323                 } else
1324                         mesh_path_flush_pending(mpath);
1325         }
1326 }
1327
1328 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1329 {
1330         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1331         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1332         u8 flags, target_flags = 0;
1333
1334         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1335                         ? RANN_FLAG_IS_GATE : 0;
1336
1337         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1338         case IEEE80211_PROACTIVE_RANN:
1339                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1340                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1341                                        0, ifmsh->mshcfg.element_ttl,
1342                                        interval, 0, 0, sdata);
1343                 break;
1344         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1345                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1346                 fallthrough;
1347         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1348                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1349                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1350                                 IEEE80211_PREQ_USN_FLAG;
1351                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1352                                        ++ifmsh->sn, target_flags,
1353                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1354                                        0, ifmsh->mshcfg.element_ttl, interval,
1355                                        0, ifmsh->preq_id++, sdata);
1356                 break;
1357         default:
1358                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1359                 return;
1360         }
1361 }