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 -ENOTSUPP;
 155         }
 156         *pos++ = ie_len;
 157         *pos++ = flags;
 158         *pos++ = hop_count;
 159         *pos++ = ttl;
 160         if (action == MPATH_PREP) {
 161                 memcpy(pos, target, ETH_ALEN);
 162                 pos += ETH_ALEN;
 163                 put_unaligned_le32(target_sn, pos);
 164                 pos += 4;
 165         } else {
 166                 if (action == MPATH_PREQ) {
 167                         put_unaligned_le32(preq_id, pos);
 168                         pos += 4;
 169                 }
 170                 memcpy(pos, orig_addr, ETH_ALEN);
 171                 pos += ETH_ALEN;
 172                 put_unaligned_le32(orig_sn, pos);
 173                 pos += 4;
 174         }
 175         put_unaligned_le32(lifetime, pos); /* interval for RANN */
 176         pos += 4;
 177         put_unaligned_le32(metric, pos);
 178         pos += 4;
 179         if (action == MPATH_PREQ) {
 180                 *pos++ = 1; /* destination count */
 181                 *pos++ = target_flags;
 182                 memcpy(pos, target, ETH_ALEN);
 183                 pos += ETH_ALEN;
 184                 put_unaligned_le32(target_sn, pos);
 185                 pos += 4;
 186         } else if (action == MPATH_PREP) {
 187                 memcpy(pos, orig_addr, ETH_ALEN);
 188                 pos += ETH_ALEN;
 189                 put_unaligned_le32(orig_sn, pos);
 190                 pos += 4;
 191         }
 192
 193         ieee80211_tx_skb(sdata, skb);
 194         return 0;
 195 }
 196
 197
 198 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 199  *  headroom in case the frame is encrypted. */
 200 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 201                 struct sk_buff *skb)
 202 {
 203         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 204         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 205
 206         skb_reset_mac_header(skb);
 207         skb_reset_network_header(skb);
 208         skb_reset_transport_header(skb);
 209
 210         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 211         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 212         skb->priority = 7;
 213
 214         info->control.vif = &sdata->vif;
 215         info->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 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 235                        u8 ttl, const u8 *target, u32 target_sn,
 236                        u16 target_rcode, const u8 *ra)
 237 {
 238         struct ieee80211_local *local = sdata->local;
 239         struct sk_buff *skb;
 240         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 241         struct ieee80211_mgmt *mgmt;
 242         u8 *pos, ie_len;
 243         int hdr_len = offsetofend(struct ieee80211_mgmt,
 244                                   u.action.u.mesh_action);
 245
 246         if (time_before(jiffies, ifmsh->next_perr))
 247                 return -EAGAIN;
 248
 249         skb = dev_alloc_skb(local->tx_headroom +
 250                             IEEE80211_ENCRYPT_HEADROOM +
 251                             IEEE80211_ENCRYPT_TAILROOM +
 252                             hdr_len +
 253                             2 + 15 /* PERR IE */);
 254         if (!skb)
 255                 return -1;
 256         skb_reserve(skb, local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM);
 257         mgmt = skb_put_zero(skb, hdr_len);
 258         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 259                                           IEEE80211_STYPE_ACTION);
 260
 261         memcpy(mgmt->da, ra, ETH_ALEN);
 262         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 263         /* BSSID == SA */
 264         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 265         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 266         mgmt->u.action.u.mesh_action.action_code =
 267                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 268         ie_len = 15;
 269         pos = skb_put(skb, 2 + ie_len);
 270         *pos++ = WLAN_EID_PERR;
 271         *pos++ = ie_len;
 272         /* ttl */
 273         *pos++ = ttl;
 274         /* number of destinations */
 275         *pos++ = 1;
 276         /* Flags field has AE bit only as defined in
 277          * sec 8.4.2.117 IEEE802.11-2012
 278          */
 279         *pos = 0;
 280         pos++;
 281         memcpy(pos, target, ETH_ALEN);
 282         pos += ETH_ALEN;
 283         put_unaligned_le32(target_sn, pos);
 284         pos += 4;
 285         put_unaligned_le16(target_rcode, pos);
 286
 287         /* see note in function header */
 288         prepare_frame_for_deferred_tx(sdata, skb);
 289         ifmsh->next_perr = TU_TO_EXP_TIME(
 290                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 291         ieee80211_add_pending_skb(local, skb);
 292         return 0;
 293 }
 294
 295 void ieee80211s_update_metric(struct ieee80211_local *local,
 296                               struct sta_info *sta,
 297                               struct ieee80211_tx_status *st)
 298 {
 299         struct ieee80211_tx_info *txinfo = st->info;
 300         int failed;
 301         struct rate_info rinfo;
 302
 303         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 304
 305         /* moving average, scaled to 100.
 306          * feed failure as 100 and success as 0
 307          */
 308         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
 309         if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
 310                         LINK_FAIL_THRESH)
 311                 mesh_plink_broken(sta);
 312
 313         /* use rate info set by the driver directly if present */
 314         if (st->n_rates)
 315                 rinfo = sta->deflink.tx_stats.last_rate_info;
 316         else
 317                 sta_set_rate_info_tx(sta, &sta->deflink.tx_stats.last_rate, &rinfo);
 318
 319         ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg,
 320                                   cfg80211_calculate_bitrate(&rinfo));
 321 }
 322
 323 u32 airtime_link_metric_get(struct ieee80211_local *local,
 324                             struct sta_info *sta)
 325 {
 326         /* This should be adjusted for each device */
 327         int device_constant = 1 << ARITH_SHIFT;
 328         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 329         int s_unit = 1 << ARITH_SHIFT;
 330         int rate, err;
 331         u32 tx_time, estimated_retx;
 332         u64 result;
 333         unsigned long fail_avg =
 334                 ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
 335
 336         if (sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 337                 return MAX_METRIC;
 338
 339         /* Try to get rate based on HW/SW RC algorithm.
 340          * Rate is returned in units of Kbps, correct this
 341          * to comply with airtime calculation units
 342          * Round up in case we get rate < 100Kbps
 343          */
 344         rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
 345
 346         if (rate) {
 347                 err = 0;
 348         } else {
 349                 if (fail_avg > LINK_FAIL_THRESH)
 350                         return MAX_METRIC;
 351
 352                 rate = ewma_mesh_tx_rate_avg_read(&sta->mesh->tx_rate_avg);
 353                 if (WARN_ON(!rate))
 354                         return MAX_METRIC;
 355
 356                 err = (fail_avg << ARITH_SHIFT) / 100;
 357         }
 358
 359         /* bitrate is in units of 100 Kbps, while we need rate in units of
 360          * 1Mbps. This will be corrected on tx_time computation.
 361          */
 362         tx_time = (device_constant + 10 * test_frame_len / rate);
 363         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 364         result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
 365         return (u32)result;
 366 }
 367
 368 /**
 369  * hwmp_route_info_get - Update routing info to originator and transmitter
 370  *
 371  * @sdata: local mesh subif
 372  * @mgmt: mesh management frame
 373  * @hwmp_ie: hwmp information element (PREP or PREQ)
 374  * @action: type of hwmp ie
 375  *
 376  * This function updates the path routing information to the originator and the
 377  * transmitter of a HWMP PREQ or PREP frame.
 378  *
 379  * Returns: metric to frame originator or 0 if the frame should not be further
 380  * processed
 381  *
 382  * Notes: this function is the only place (besides user-provided info) where
 383  * path routing information is updated.
 384  */
 385 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 386                                struct ieee80211_mgmt *mgmt,
 387                                const u8 *hwmp_ie, enum mpath_frame_type action)
 388 {
 389         struct ieee80211_local *local = sdata->local;
 390         struct mesh_path *mpath;
 391         struct sta_info *sta;
 392         bool fresh_info;
 393         const u8 *orig_addr, *ta;
 394         u32 orig_sn, orig_metric;
 395         unsigned long orig_lifetime, exp_time;
 396         u32 last_hop_metric, new_metric;
 397         bool flush_mpath = false;
 398         bool process = true;
 399         u8 hopcount;
 400
 401         rcu_read_lock();
 402         sta = sta_info_get(sdata, mgmt->sa);
 403         if (!sta) {
 404                 rcu_read_unlock();
 405                 return 0;
 406         }
 407
 408         last_hop_metric = airtime_link_metric_get(local, sta);
 409         /* Update and check originator routing info */
 410         fresh_info = true;
 411
 412         switch (action) {
 413         case MPATH_PREQ:
 414                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 415                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 416                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 417                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 418                 hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1;
 419                 break;
 420         case MPATH_PREP:
 421                 /* Originator here refers to the MP that was the target in the
 422                  * Path Request. We divert from the nomenclature in the draft
 423                  * so that we can easily use a single function to gather path
 424                  * information from both PREQ and PREP frames.
 425                  */
 426                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 427                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 428                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 429                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 430                 hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1;
 431                 break;
 432         default:
 433                 rcu_read_unlock();
 434                 return 0;
 435         }
 436         new_metric = orig_metric + last_hop_metric;
 437         if (new_metric < orig_metric)
 438                 new_metric = MAX_METRIC;
 439         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 440
 441         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 442                 /* This MP is the originator, we are not interested in this
 443                  * frame, except for updating transmitter's path info.
 444                  */
 445                 process = false;
 446                 fresh_info = false;
 447         } else {
 448                 mpath = mesh_path_lookup(sdata, orig_addr);
 449                 if (mpath) {
 450                         spin_lock_bh(&mpath->state_lock);
 451                         if (mpath->flags & MESH_PATH_FIXED)
 452                                 fresh_info = false;
 453                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 454                             (mpath->flags & MESH_PATH_SN_VALID)) {
 455                                 if (SN_GT(mpath->sn, orig_sn) ||
 456                                     (mpath->sn == orig_sn &&
 457                                      (rcu_access_pointer(mpath->next_hop) !=
 458                                                       sta ?
 459                                               mult_frac(new_metric, 10, 9) :
 460                                               new_metric) >= mpath->metric)) {
 461                                         process = false;
 462                                         fresh_info = false;
 463                                 }
 464                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 465                                 bool have_sn, newer_sn, bounced;
 466
 467                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 468                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 469                                 bounced = have_sn &&
 470                                           (SN_DELTA(orig_sn, mpath->sn) >
 471                                                         MAX_SANE_SN_DELTA);
 472
 473                                 if (!have_sn || newer_sn) {
 474                                         /* if SN is newer than what we had
 475                                          * then we can take it */;
 476                                 } else if (bounced) {
 477                                         /* if SN is way different than what
 478                                          * we had then assume the other side
 479                                          * rebooted or restarted */;
 480                                 } else {
 481                                         process = false;
 482                                         fresh_info = false;
 483                                 }
 484                         }
 485                 } else {
 486                         mpath = mesh_path_add(sdata, orig_addr);
 487                         if (IS_ERR(mpath)) {
 488                                 rcu_read_unlock();
 489                                 return 0;
 490                         }
 491                         spin_lock_bh(&mpath->state_lock);
 492                 }
 493
 494                 if (fresh_info) {
 495                         if (rcu_access_pointer(mpath->next_hop) != sta) {
 496                                 mpath->path_change_count++;
 497                                 flush_mpath = true;
 498                         }
 499                         mesh_path_assign_nexthop(mpath, sta);
 500                         mpath->flags |= MESH_PATH_SN_VALID;
 501                         mpath->metric = new_metric;
 502                         mpath->sn = orig_sn;
 503                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 504                                           ?  mpath->exp_time : exp_time;
 505                         mpath->hop_count = hopcount;
 506                         mesh_path_activate(mpath);
 507                         spin_unlock_bh(&mpath->state_lock);
 508                         if (flush_mpath)
 509                                 mesh_fast_tx_flush_mpath(mpath);
 510                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 511                         /* init it at a low value - 0 start is tricky */
 512                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 513                         mesh_path_tx_pending(mpath);
 514                         /* draft says preq_id should be saved to, but there does
 515                          * not seem to be any use for it, skipping by now
 516                          */
 517                 } else
 518                         spin_unlock_bh(&mpath->state_lock);
 519         }
 520
 521         /* Update and check transmitter routing info */
 522         ta = mgmt->sa;
 523         if (ether_addr_equal(orig_addr, ta))
 524                 fresh_info = false;
 525         else {
 526                 fresh_info = true;
 527
 528                 mpath = mesh_path_lookup(sdata, ta);
 529                 if (mpath) {
 530                         spin_lock_bh(&mpath->state_lock);
 531                         if ((mpath->flags & MESH_PATH_FIXED) ||
 532                             ((mpath->flags & MESH_PATH_ACTIVE) &&
 533                              ((rcu_access_pointer(mpath->next_hop) != sta ?
 534                                        mult_frac(last_hop_metric, 10, 9) :
 535                                        last_hop_metric) > mpath->metric)))
 536                                 fresh_info = false;
 537                 } else {
 538                         mpath = mesh_path_add(sdata, ta);
 539                         if (IS_ERR(mpath)) {
 540                                 rcu_read_unlock();
 541                                 return 0;
 542                         }
 543                         spin_lock_bh(&mpath->state_lock);
 544                 }
 545
 546                 if (fresh_info) {
 547                         if (rcu_access_pointer(mpath->next_hop) != sta) {
 548                                 mpath->path_change_count++;
 549                                 flush_mpath = true;
 550                         }
 551                         mesh_path_assign_nexthop(mpath, sta);
 552                         mpath->metric = last_hop_metric;
 553                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 554                                           ?  mpath->exp_time : exp_time;
 555                         mpath->hop_count = 1;
 556                         mesh_path_activate(mpath);
 557                         spin_unlock_bh(&mpath->state_lock);
 558                         if (flush_mpath)
 559                                 mesh_fast_tx_flush_mpath(mpath);
 560                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 561                         /* init it at a low value - 0 start is tricky */
 562                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 563                         mesh_path_tx_pending(mpath);
 564                 } else
 565                         spin_unlock_bh(&mpath->state_lock);
 566         }
 567
 568         rcu_read_unlock();
 569
 570         return process ? new_metric : 0;
 571 }
 572
 573 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 574                                     struct ieee80211_mgmt *mgmt,
 575                                     const u8 *preq_elem, u32 orig_metric)
 576 {
 577         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 578         struct mesh_path *mpath = NULL;
 579         const u8 *target_addr, *orig_addr;
 580         const u8 *da;
 581         u8 target_flags, ttl, flags;
 582         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 583         bool reply = false;
 584         bool forward = true;
 585         bool root_is_gate;
 586
 587         /* Update target SN, if present */
 588         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 589         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 590         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 591         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 592         target_flags = PREQ_IE_TARGET_F(preq_elem);
 593         /* Proactive PREQ gate announcements */
 594         flags = PREQ_IE_FLAGS(preq_elem);
 595         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 596
 597         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 598
 599         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 600                 mhwmp_dbg(sdata, "PREQ is for us\n");
 601                 forward = false;
 602                 reply = true;
 603                 target_metric = 0;
 604
 605                 if (SN_GT(target_sn, ifmsh->sn))
 606                         ifmsh->sn = target_sn;
 607
 608                 if (time_after(jiffies, ifmsh->last_sn_update +
 609                                         net_traversal_jiffies(sdata)) ||
 610                     time_before(jiffies, ifmsh->last_sn_update)) {
 611                         ++ifmsh->sn;
 612                         ifmsh->last_sn_update = jiffies;
 613                 }
 614                 target_sn = ifmsh->sn;
 615         } else if (is_broadcast_ether_addr(target_addr) &&
 616                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 617                 rcu_read_lock();
 618                 mpath = mesh_path_lookup(sdata, orig_addr);
 619                 if (mpath) {
 620                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 621                                 reply = true;
 622                                 target_addr = sdata->vif.addr;
 623                                 target_sn = ++ifmsh->sn;
 624                                 target_metric = 0;
 625                                 ifmsh->last_sn_update = jiffies;
 626                         }
 627                         if (root_is_gate)
 628                                 mesh_path_add_gate(mpath);
 629                 }
 630                 rcu_read_unlock();
 631         } else {
 632                 rcu_read_lock();
 633                 mpath = mesh_path_lookup(sdata, target_addr);
 634                 if (mpath) {
 635                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 636                                         SN_LT(mpath->sn, target_sn)) {
 637                                 mpath->sn = target_sn;
 638                                 mpath->flags |= MESH_PATH_SN_VALID;
 639                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 640                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 641                                 reply = true;
 642                                 target_metric = mpath->metric;
 643                                 target_sn = mpath->sn;
 644                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 645                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 646                         }
 647                 }
 648                 rcu_read_unlock();
 649         }
 650
 651         if (reply) {
 652                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 653                 ttl = ifmsh->mshcfg.element_ttl;
 654                 if (ttl != 0) {
 655                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 656                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 657                                                orig_sn, 0, target_addr,
 658                                                target_sn, mgmt->sa, 0, ttl,
 659                                                lifetime, target_metric, 0,
 660                                                sdata);
 661                 } else {
 662                         ifmsh->mshstats.dropped_frames_ttl++;
 663                 }
 664         }
 665
 666         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 667                 u32 preq_id;
 668                 u8 hopcount;
 669
 670                 ttl = PREQ_IE_TTL(preq_elem);
 671                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 672                 if (ttl <= 1) {
 673                         ifmsh->mshstats.dropped_frames_ttl++;
 674                         return;
 675                 }
 676                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 677                 --ttl;
 678                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 679                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 680                 da = (mpath && mpath->is_root) ?
 681                         mpath->rann_snd_addr : broadcast_addr;
 682
 683                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 684                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 685                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 686                 }
 687
 688                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 689                                        orig_sn, target_flags, target_addr,
 690                                        target_sn, da, hopcount, ttl, lifetime,
 691                                        orig_metric, preq_id, sdata);
 692                 if (!is_multicast_ether_addr(da))
 693                         ifmsh->mshstats.fwded_unicast++;
 694                 else
 695                         ifmsh->mshstats.fwded_mcast++;
 696                 ifmsh->mshstats.fwded_frames++;
 697         }
 698 }
 699
 700
 701 static inline struct sta_info *
 702 next_hop_deref_protected(struct mesh_path *mpath)
 703 {
 704         return rcu_dereference_protected(mpath->next_hop,
 705                                          lockdep_is_held(&mpath->state_lock));
 706 }
 707
 708
 709 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 710                                     struct ieee80211_mgmt *mgmt,
 711                                     const u8 *prep_elem, u32 metric)
 712 {
 713         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 714         struct mesh_path *mpath;
 715         const u8 *target_addr, *orig_addr;
 716         u8 ttl, hopcount, flags;
 717         u8 next_hop[ETH_ALEN];
 718         u32 target_sn, orig_sn, lifetime;
 719
 720         mhwmp_dbg(sdata, "received PREP from %pM\n",
 721                   PREP_IE_TARGET_ADDR(prep_elem));
 722
 723         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 724         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 725                 /* destination, no forwarding required */
 726                 return;
 727
 728         if (!ifmsh->mshcfg.dot11MeshForwarding)
 729                 return;
 730
 731         ttl = PREP_IE_TTL(prep_elem);
 732         if (ttl <= 1) {
 733                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 734                 return;
 735         }
 736
 737         rcu_read_lock();
 738         mpath = mesh_path_lookup(sdata, orig_addr);
 739         if (mpath)
 740                 spin_lock_bh(&mpath->state_lock);
 741         else
 742                 goto fail;
 743         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 744                 spin_unlock_bh(&mpath->state_lock);
 745                 goto fail;
 746         }
 747         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 748         spin_unlock_bh(&mpath->state_lock);
 749         --ttl;
 750         flags = PREP_IE_FLAGS(prep_elem);
 751         lifetime = PREP_IE_LIFETIME(prep_elem);
 752         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 753         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 754         target_sn = PREP_IE_TARGET_SN(prep_elem);
 755         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 756
 757         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 758                                target_addr, target_sn, next_hop, hopcount,
 759                                ttl, lifetime, metric, 0, sdata);
 760         rcu_read_unlock();
 761
 762         sdata->u.mesh.mshstats.fwded_unicast++;
 763         sdata->u.mesh.mshstats.fwded_frames++;
 764         return;
 765
 766 fail:
 767         rcu_read_unlock();
 768         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 769 }
 770
 771 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 772                                     struct ieee80211_mgmt *mgmt,
 773                                     const u8 *perr_elem)
 774 {
 775         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 776         struct mesh_path *mpath;
 777         u8 ttl;
 778         const u8 *ta, *target_addr;
 779         u32 target_sn;
 780         u16 target_rcode;
 781
 782         ta = mgmt->sa;
 783         ttl = PERR_IE_TTL(perr_elem);
 784         if (ttl <= 1) {
 785                 ifmsh->mshstats.dropped_frames_ttl++;
 786                 return;
 787         }
 788         ttl--;
 789         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 790         target_sn = PERR_IE_TARGET_SN(perr_elem);
 791         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 792
 793         rcu_read_lock();
 794         mpath = mesh_path_lookup(sdata, target_addr);
 795         if (mpath) {
 796                 struct sta_info *sta;
 797
 798                 spin_lock_bh(&mpath->state_lock);
 799                 sta = next_hop_deref_protected(mpath);
 800                 if (mpath->flags & MESH_PATH_ACTIVE &&
 801                     ether_addr_equal(ta, sta->sta.addr) &&
 802                     !(mpath->flags & MESH_PATH_FIXED) &&
 803                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 804                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 805                         mpath->flags &= ~MESH_PATH_ACTIVE;
 806                         if (target_sn != 0)
 807                                 mpath->sn = target_sn;
 808                         else
 809                                 mpath->sn += 1;
 810                         spin_unlock_bh(&mpath->state_lock);
 811                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 812                                 goto endperr;
 813                         mesh_path_error_tx(sdata, ttl, target_addr,
 814                                            target_sn, target_rcode,
 815                                            broadcast_addr);
 816                 } else
 817                         spin_unlock_bh(&mpath->state_lock);
 818         }
 819 endperr:
 820         rcu_read_unlock();
 821 }
 822
 823 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 824                                     struct ieee80211_mgmt *mgmt,
 825                                     const struct ieee80211_rann_ie *rann)
 826 {
 827         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 828         struct ieee80211_local *local = sdata->local;
 829         struct sta_info *sta;
 830         struct mesh_path *mpath;
 831         u8 ttl, flags, hopcount;
 832         const u8 *orig_addr;
 833         u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
 834         bool root_is_gate;
 835
 836         ttl = rann->rann_ttl;
 837         flags = rann->rann_flags;
 838         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 839         orig_addr = rann->rann_addr;
 840         orig_sn = le32_to_cpu(rann->rann_seq);
 841         interval = le32_to_cpu(rann->rann_interval);
 842         hopcount = rann->rann_hopcount;
 843         hopcount++;
 844         orig_metric = le32_to_cpu(rann->rann_metric);
 845
 846         /*  Ignore our own RANNs */
 847         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 848                 return;
 849
 850         mhwmp_dbg(sdata,
 851                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 852                   orig_addr, mgmt->sa, root_is_gate);
 853
 854         rcu_read_lock();
 855         sta = sta_info_get(sdata, mgmt->sa);
 856         if (!sta) {
 857                 rcu_read_unlock();
 858                 return;
 859         }
 860
 861         last_hop_metric = airtime_link_metric_get(local, sta);
 862         new_metric = orig_metric + last_hop_metric;
 863         if (new_metric < orig_metric)
 864                 new_metric = MAX_METRIC;
 865
 866         mpath = mesh_path_lookup(sdata, orig_addr);
 867         if (!mpath) {
 868                 mpath = mesh_path_add(sdata, orig_addr);
 869                 if (IS_ERR(mpath)) {
 870                         rcu_read_unlock();
 871                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 872                         return;
 873                 }
 874         }
 875
 876         if (!(SN_LT(mpath->sn, orig_sn)) &&
 877             !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
 878                 rcu_read_unlock();
 879                 return;
 880         }
 881
 882         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 883              (time_after(jiffies, mpath->last_preq_to_root +
 884                                   root_path_confirmation_jiffies(sdata)) ||
 885              time_before(jiffies, mpath->last_preq_to_root))) &&
 886              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 887                 mhwmp_dbg(sdata,
 888                           "time to refresh root mpath %pM\n",
 889                           orig_addr);
 890                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 891                 mpath->last_preq_to_root = jiffies;
 892         }
 893
 894         mpath->sn = orig_sn;
 895         mpath->rann_metric = new_metric;
 896         mpath->is_root = true;
 897         /* Recording RANNs sender address to send individually
 898          * addressed PREQs destined for root mesh STA */
 899         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 900
 901         if (root_is_gate)
 902                 mesh_path_add_gate(mpath);
 903
 904         if (ttl <= 1) {
 905                 ifmsh->mshstats.dropped_frames_ttl++;
 906                 rcu_read_unlock();
 907                 return;
 908         }
 909         ttl--;
 910
 911         if (ifmsh->mshcfg.dot11MeshForwarding) {
 912                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 913                                        orig_sn, 0, NULL, 0, broadcast_addr,
 914                                        hopcount, ttl, interval,
 915                                        new_metric, 0, sdata);
 916         }
 917
 918         rcu_read_unlock();
 919 }
 920
 921
 922 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 923                             struct ieee80211_mgmt *mgmt, size_t len)
 924 {
 925         struct ieee802_11_elems *elems;
 926         size_t baselen;
 927         u32 path_metric;
 928         struct sta_info *sta;
 929
 930         /* need action_code */
 931         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 932                 return;
 933
 934         rcu_read_lock();
 935         sta = sta_info_get(sdata, mgmt->sa);
 936         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 937                 rcu_read_unlock();
 938                 return;
 939         }
 940         rcu_read_unlock();
 941
 942         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 943         elems = ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 944                                        len - baselen, false, NULL);
 945         if (!elems)
 946                 return;
 947
 948         if (elems->preq) {
 949                 if (elems->preq_len != 37)
 950                         /* Right now we support just 1 destination and no AE */
 951                         goto free;
 952                 path_metric = hwmp_route_info_get(sdata, mgmt, elems->preq,
 953                                                   MPATH_PREQ);
 954                 if (path_metric)
 955                         hwmp_preq_frame_process(sdata, mgmt, elems->preq,
 956                                                 path_metric);
 957         }
 958         if (elems->prep) {
 959                 if (elems->prep_len != 31)
 960                         /* Right now we support no AE */
 961                         goto free;
 962                 path_metric = hwmp_route_info_get(sdata, mgmt, elems->prep,
 963                                                   MPATH_PREP);
 964                 if (path_metric)
 965                         hwmp_prep_frame_process(sdata, mgmt, elems->prep,
 966                                                 path_metric);
 967         }
 968         if (elems->perr) {
 969                 if (elems->perr_len != 15)
 970                         /* Right now we support only one destination per PERR */
 971                         goto free;
 972                 hwmp_perr_frame_process(sdata, mgmt, elems->perr);
 973         }
 974         if (elems->rann)
 975                 hwmp_rann_frame_process(sdata, mgmt, elems->rann);
 976 free:
 977         kfree(elems);
 978 }
 979
 980 /**
 981  * mesh_queue_preq - queue a PREQ to a given destination
 982  *
 983  * @mpath: mesh path to discover
 984  * @flags: special attributes of the PREQ to be sent
 985  *
 986  * Locking: the function must be called from within a rcu read lock block.
 987  *
 988  */
 989 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 990 {
 991         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 992         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 993         struct mesh_preq_queue *preq_node;
 994
 995         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 996         if (!preq_node) {
 997                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 998                 return;
 999         }
1000
1001         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1002         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
1003                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1004                 kfree(preq_node);
1005                 if (printk_ratelimit())
1006                         mhwmp_dbg(sdata, "PREQ node queue full\n");
1007                 return;
1008         }
1009
1010         spin_lock(&mpath->state_lock);
1011         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
1012                 spin_unlock(&mpath->state_lock);
1013                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1014                 kfree(preq_node);
1015                 return;
1016         }
1017
1018         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
1019         preq_node->flags = flags;
1020
1021         mpath->flags |= MESH_PATH_REQ_QUEUED;
1022         spin_unlock(&mpath->state_lock);
1023
1024         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
1025         ++ifmsh->preq_queue_len;
1026         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1027
1028         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
1029                 wiphy_work_queue(sdata->local->hw.wiphy, &sdata->work);
1030
1031         else if (time_before(jiffies, ifmsh->last_preq)) {
1032                 /* avoid long wait if did not send preqs for a long time
1033                  * and jiffies wrapped around
1034                  */
1035                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1036                 wiphy_work_queue(sdata->local->hw.wiphy, &sdata->work);
1037         } else
1038                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1039                                                 min_preq_int_jiff(sdata));
1040 }
1041
1042 /**
1043  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1044  *
1045  * @sdata: local mesh subif
1046  */
1047 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1048 {
1049         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1050         struct mesh_preq_queue *preq_node;
1051         struct mesh_path *mpath;
1052         u8 ttl, target_flags = 0;
1053         const u8 *da;
1054         u32 lifetime;
1055
1056         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1057         if (!ifmsh->preq_queue_len ||
1058                 time_before(jiffies, ifmsh->last_preq +
1059                                 min_preq_int_jiff(sdata))) {
1060                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1061                 return;
1062         }
1063
1064         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1065                         struct mesh_preq_queue, list);
1066         list_del(&preq_node->list);
1067         --ifmsh->preq_queue_len;
1068         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1069
1070         rcu_read_lock();
1071         mpath = mesh_path_lookup(sdata, preq_node->dst);
1072         if (!mpath)
1073                 goto enddiscovery;
1074
1075         spin_lock_bh(&mpath->state_lock);
1076         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1077                 spin_unlock_bh(&mpath->state_lock);
1078                 goto enddiscovery;
1079         }
1080         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1081         if (preq_node->flags & PREQ_Q_F_START) {
1082                 if (mpath->flags & MESH_PATH_RESOLVING) {
1083                         spin_unlock_bh(&mpath->state_lock);
1084                         goto enddiscovery;
1085                 } else {
1086                         mpath->flags &= ~MESH_PATH_RESOLVED;
1087                         mpath->flags |= MESH_PATH_RESOLVING;
1088                         mpath->discovery_retries = 0;
1089                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1090                 }
1091         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1092                         mpath->flags & MESH_PATH_RESOLVED) {
1093                 mpath->flags &= ~MESH_PATH_RESOLVING;
1094                 spin_unlock_bh(&mpath->state_lock);
1095                 goto enddiscovery;
1096         }
1097
1098         ifmsh->last_preq = jiffies;
1099
1100         if (time_after(jiffies, ifmsh->last_sn_update +
1101                                 net_traversal_jiffies(sdata)) ||
1102             time_before(jiffies, ifmsh->last_sn_update)) {
1103                 ++ifmsh->sn;
1104                 sdata->u.mesh.last_sn_update = jiffies;
1105         }
1106         lifetime = default_lifetime(sdata);
1107         ttl = sdata->u.mesh.mshcfg.element_ttl;
1108         if (ttl == 0) {
1109                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1110                 spin_unlock_bh(&mpath->state_lock);
1111                 goto enddiscovery;
1112         }
1113
1114         if (preq_node->flags & PREQ_Q_F_REFRESH)
1115                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1116         else
1117                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1118
1119         spin_unlock_bh(&mpath->state_lock);
1120         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1121         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1122                                target_flags, mpath->dst, mpath->sn, da, 0,
1123                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1124
1125         spin_lock_bh(&mpath->state_lock);
1126         if (!(mpath->flags & MESH_PATH_DELETED))
1127                 mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1128         spin_unlock_bh(&mpath->state_lock);
1129
1130 enddiscovery:
1131         rcu_read_unlock();
1132         kfree(preq_node);
1133 }
1134
1135 /**
1136  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1137  *
1138  * @skb: 802.11 frame to be sent
1139  * @sdata: network subif the frame will be sent through
1140  *
1141  * Lookup next hop for given skb and start path discovery if no
1142  * forwarding information is found.
1143  *
1144  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1145  * skb is freed here if no mpath could be allocated.
1146  */
1147 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1148                          struct sk_buff *skb)
1149 {
1150         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1151         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1152         struct mesh_path *mpath;
1153         struct sk_buff *skb_to_free = NULL;
1154         u8 *target_addr = hdr->addr3;
1155
1156         /* Nulls are only sent to peers for PS and should be pre-addressed */
1157         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1158                 return 0;
1159
1160         /* Allow injected packets to bypass mesh routing */
1161         if (info->control.flags & IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP)
1162                 return 0;
1163
1164         if (!mesh_nexthop_lookup(sdata, skb))
1165                 return 0;
1166
1167         /* no nexthop found, start resolving */
1168         mpath = mesh_path_lookup(sdata, target_addr);
1169         if (!mpath) {
1170                 mpath = mesh_path_add(sdata, target_addr);
1171                 if (IS_ERR(mpath)) {
1172                         mesh_path_discard_frame(sdata, skb);
1173                         return PTR_ERR(mpath);
1174                 }
1175         }
1176
1177         if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1178             mesh_path_sel_is_hwmp(sdata))
1179                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1180
1181         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1182                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1183
1184         info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
1185         ieee80211_set_qos_hdr(sdata, skb);
1186         skb_queue_tail(&mpath->frame_queue, skb);
1187         if (skb_to_free)
1188                 mesh_path_discard_frame(sdata, skb_to_free);
1189
1190         return -ENOENT;
1191 }
1192
1193 /**
1194  * mesh_nexthop_lookup_nolearn - try to set next hop without path discovery
1195  * @skb: 802.11 frame to be sent
1196  * @sdata: network subif the frame will be sent through
1197  *
1198  * Check if the meshDA (addr3) of a unicast frame is a direct neighbor.
1199  * And if so, set the RA (addr1) to it to transmit to this node directly,
1200  * avoiding PREQ/PREP path discovery.
1201  *
1202  * Returns: 0 if the next hop was found and -ENOENT otherwise.
1203  */
1204 static int mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data *sdata,
1205                                        struct sk_buff *skb)
1206 {
1207         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1208         struct sta_info *sta;
1209
1210         if (is_multicast_ether_addr(hdr->addr1))
1211                 return -ENOENT;
1212
1213         rcu_read_lock();
1214         sta = sta_info_get(sdata, hdr->addr3);
1215
1216         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
1217                 rcu_read_unlock();
1218                 return -ENOENT;
1219         }
1220         rcu_read_unlock();
1221
1222         memcpy(hdr->addr1, hdr->addr3, ETH_ALEN);
1223         memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1224         return 0;
1225 }
1226
1227 void mesh_path_refresh(struct ieee80211_sub_if_data *sdata,
1228                        struct mesh_path *mpath, const u8 *addr)
1229 {
1230         if (mpath->flags & (MESH_PATH_REQ_QUEUED | MESH_PATH_FIXED |
1231                             MESH_PATH_RESOLVING))
1232                 return;
1233
1234         if (time_after(jiffies,
1235                        mpath->exp_time -
1236                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1237             (!addr || ether_addr_equal(sdata->vif.addr, addr)))
1238                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1239 }
1240
1241 /**
1242  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1243  * this function is considered "using" the associated mpath, so preempt a path
1244  * refresh if this mpath expires soon.
1245  *
1246  * @skb: 802.11 frame to be sent
1247  * @sdata: network subif the frame will be sent through
1248  *
1249  * Returns: 0 if the next hop was found. Nonzero otherwise.
1250  */
1251 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1252                         struct sk_buff *skb)
1253 {
1254         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1255         struct mesh_path *mpath;
1256         struct sta_info *next_hop;
1257         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1258         u8 *target_addr = hdr->addr3;
1259
1260         if (ifmsh->mshcfg.dot11MeshNolearn &&
1261             !mesh_nexthop_lookup_nolearn(sdata, skb))
1262                 return 0;
1263
1264         mpath = mesh_path_lookup(sdata, target_addr);
1265         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1266                 return -ENOENT;
1267
1268         mesh_path_refresh(sdata, mpath, hdr->addr4);
1269
1270         next_hop = rcu_dereference(mpath->next_hop);
1271         if (next_hop) {
1272                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1273                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1274                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1275                 if (ieee80211_hw_check(&sdata->local->hw, SUPPORT_FAST_XMIT))
1276                         mesh_fast_tx_cache(sdata, skb, mpath);
1277                 return 0;
1278         }
1279
1280         return -ENOENT;
1281 }
1282
1283 void mesh_path_timer(struct timer_list *t)
1284 {
1285         struct mesh_path *mpath = from_timer(mpath, t, timer);
1286         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1287         int ret;
1288
1289         if (sdata->local->quiescing)
1290                 return;
1291
1292         spin_lock_bh(&mpath->state_lock);
1293         if (mpath->flags & MESH_PATH_RESOLVED ||
1294                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1295                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1296                 spin_unlock_bh(&mpath->state_lock);
1297         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1298                 ++mpath->discovery_retries;
1299                 mpath->discovery_timeout *= 2;
1300                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1301                 spin_unlock_bh(&mpath->state_lock);
1302                 mesh_queue_preq(mpath, 0);
1303         } else {
1304                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1305                                   MESH_PATH_RESOLVED |
1306                                   MESH_PATH_REQ_QUEUED);
1307                 mpath->exp_time = jiffies;
1308                 spin_unlock_bh(&mpath->state_lock);
1309                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1310                         ret = mesh_path_send_to_gates(mpath);
1311                         if (ret)
1312                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1313                 } else
1314                         mesh_path_flush_pending(mpath);
1315         }
1316 }
1317
1318 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1319 {
1320         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1321         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1322         u8 flags, target_flags = 0;
1323
1324         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1325                         ? RANN_FLAG_IS_GATE : 0;
1326
1327         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1328         case IEEE80211_PROACTIVE_RANN:
1329                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1330                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1331                                        0, ifmsh->mshcfg.element_ttl,
1332                                        interval, 0, 0, sdata);
1333                 break;
1334         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1335                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1336                 fallthrough;
1337         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1338                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1339                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1340                                 IEEE80211_PREQ_USN_FLAG;
1341                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1342                                        ++ifmsh->sn, target_flags,
1343                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1344                                        0, ifmsh->mshcfg.element_ttl, interval,
1345                                        0, ifmsh->preq_id++, sdata);
1346                 break;
1347         default:
1348                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1349                 return;
1350         }
1351 }