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, 2021-2022 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 process = true;
 398         u8 hopcount;
 399
 400         rcu_read_lock();
 401         sta = sta_info_get(sdata, mgmt->sa);
 402         if (!sta) {
 403                 rcu_read_unlock();
 404                 return 0;
 405         }
 406
 407         last_hop_metric = airtime_link_metric_get(local, sta);
 408         /* Update and check originator routing info */
 409         fresh_info = true;
 410
 411         switch (action) {
 412         case MPATH_PREQ:
 413                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 414                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 415                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 416                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 417                 hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1;
 418                 break;
 419         case MPATH_PREP:
 420                 /* Originator here refers to the MP that was the target in the
 421                  * Path Request. We divert from the nomenclature in the draft
 422                  * so that we can easily use a single function to gather path
 423                  * information from both PREQ and PREP frames.
 424                  */
 425                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 426                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 427                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 428                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 429                 hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1;
 430                 break;
 431         default:
 432                 rcu_read_unlock();
 433                 return 0;
 434         }
 435         new_metric = orig_metric + last_hop_metric;
 436         if (new_metric < orig_metric)
 437                 new_metric = MAX_METRIC;
 438         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 439
 440         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 441                 /* This MP is the originator, we are not interested in this
 442                  * frame, except for updating transmitter's path info.
 443                  */
 444                 process = false;
 445                 fresh_info = false;
 446         } else {
 447                 mpath = mesh_path_lookup(sdata, orig_addr);
 448                 if (mpath) {
 449                         spin_lock_bh(&mpath->state_lock);
 450                         if (mpath->flags & MESH_PATH_FIXED)
 451                                 fresh_info = false;
 452                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 453                             (mpath->flags & MESH_PATH_SN_VALID)) {
 454                                 if (SN_GT(mpath->sn, orig_sn) ||
 455                                     (mpath->sn == orig_sn &&
 456                                      (rcu_access_pointer(mpath->next_hop) !=
 457                                                       sta ?
 458                                               mult_frac(new_metric, 10, 9) :
 459                                               new_metric) >= mpath->metric)) {
 460                                         process = false;
 461                                         fresh_info = false;
 462                                 }
 463                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 464                                 bool have_sn, newer_sn, bounced;
 465
 466                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 467                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 468                                 bounced = have_sn &&
 469                                           (SN_DELTA(orig_sn, mpath->sn) >
 470                                                         MAX_SANE_SN_DELTA);
 471
 472                                 if (!have_sn || newer_sn) {
 473                                         /* if SN is newer than what we had
 474                                          * then we can take it */;
 475                                 } else if (bounced) {
 476                                         /* if SN is way different than what
 477                                          * we had then assume the other side
 478                                          * rebooted or restarted */;
 479                                 } else {
 480                                         process = false;
 481                                         fresh_info = false;
 482                                 }
 483                         }
 484                 } else {
 485                         mpath = mesh_path_add(sdata, orig_addr);
 486                         if (IS_ERR(mpath)) {
 487                                 rcu_read_unlock();
 488                                 return 0;
 489                         }
 490                         spin_lock_bh(&mpath->state_lock);
 491                 }
 492
 493                 if (fresh_info) {
 494                         if (rcu_access_pointer(mpath->next_hop) != sta)
 495                                 mpath->path_change_count++;
 496                         mesh_path_assign_nexthop(mpath, sta);
 497                         mpath->flags |= MESH_PATH_SN_VALID;
 498                         mpath->metric = new_metric;
 499                         mpath->sn = orig_sn;
 500                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 501                                           ?  mpath->exp_time : exp_time;
 502                         mpath->hop_count = hopcount;
 503                         mesh_path_activate(mpath);
 504                         spin_unlock_bh(&mpath->state_lock);
 505                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 506                         /* init it at a low value - 0 start is tricky */
 507                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 508                         mesh_path_tx_pending(mpath);
 509                         /* draft says preq_id should be saved to, but there does
 510                          * not seem to be any use for it, skipping by now
 511                          */
 512                 } else
 513                         spin_unlock_bh(&mpath->state_lock);
 514         }
 515
 516         /* Update and check transmitter routing info */
 517         ta = mgmt->sa;
 518         if (ether_addr_equal(orig_addr, ta))
 519                 fresh_info = false;
 520         else {
 521                 fresh_info = true;
 522
 523                 mpath = mesh_path_lookup(sdata, ta);
 524                 if (mpath) {
 525                         spin_lock_bh(&mpath->state_lock);
 526                         if ((mpath->flags & MESH_PATH_FIXED) ||
 527                             ((mpath->flags & MESH_PATH_ACTIVE) &&
 528                              ((rcu_access_pointer(mpath->next_hop) != sta ?
 529                                        mult_frac(last_hop_metric, 10, 9) :
 530                                        last_hop_metric) > mpath->metric)))
 531                                 fresh_info = false;
 532                 } else {
 533                         mpath = mesh_path_add(sdata, ta);
 534                         if (IS_ERR(mpath)) {
 535                                 rcu_read_unlock();
 536                                 return 0;
 537                         }
 538                         spin_lock_bh(&mpath->state_lock);
 539                 }
 540
 541                 if (fresh_info) {
 542                         if (rcu_access_pointer(mpath->next_hop) != sta)
 543                                 mpath->path_change_count++;
 544                         mesh_path_assign_nexthop(mpath, sta);
 545                         mpath->metric = last_hop_metric;
 546                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 547                                           ?  mpath->exp_time : exp_time;
 548                         mpath->hop_count = 1;
 549                         mesh_path_activate(mpath);
 550                         spin_unlock_bh(&mpath->state_lock);
 551                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 552                         /* init it at a low value - 0 start is tricky */
 553                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 554                         mesh_path_tx_pending(mpath);
 555                 } else
 556                         spin_unlock_bh(&mpath->state_lock);
 557         }
 558
 559         rcu_read_unlock();
 560
 561         return process ? new_metric : 0;
 562 }
 563
 564 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 565                                     struct ieee80211_mgmt *mgmt,
 566                                     const u8 *preq_elem, u32 orig_metric)
 567 {
 568         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 569         struct mesh_path *mpath = NULL;
 570         const u8 *target_addr, *orig_addr;
 571         const u8 *da;
 572         u8 target_flags, ttl, flags;
 573         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 574         bool reply = false;
 575         bool forward = true;
 576         bool root_is_gate;
 577
 578         /* Update target SN, if present */
 579         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 580         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 581         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 582         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 583         target_flags = PREQ_IE_TARGET_F(preq_elem);
 584         /* Proactive PREQ gate announcements */
 585         flags = PREQ_IE_FLAGS(preq_elem);
 586         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 587
 588         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 589
 590         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 591                 mhwmp_dbg(sdata, "PREQ is for us\n");
 592                 forward = false;
 593                 reply = true;
 594                 target_metric = 0;
 595
 596                 if (SN_GT(target_sn, ifmsh->sn))
 597                         ifmsh->sn = target_sn;
 598
 599                 if (time_after(jiffies, ifmsh->last_sn_update +
 600                                         net_traversal_jiffies(sdata)) ||
 601                     time_before(jiffies, ifmsh->last_sn_update)) {
 602                         ++ifmsh->sn;
 603                         ifmsh->last_sn_update = jiffies;
 604                 }
 605                 target_sn = ifmsh->sn;
 606         } else if (is_broadcast_ether_addr(target_addr) &&
 607                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 608                 rcu_read_lock();
 609                 mpath = mesh_path_lookup(sdata, orig_addr);
 610                 if (mpath) {
 611                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 612                                 reply = true;
 613                                 target_addr = sdata->vif.addr;
 614                                 target_sn = ++ifmsh->sn;
 615                                 target_metric = 0;
 616                                 ifmsh->last_sn_update = jiffies;
 617                         }
 618                         if (root_is_gate)
 619                                 mesh_path_add_gate(mpath);
 620                 }
 621                 rcu_read_unlock();
 622         } else {
 623                 rcu_read_lock();
 624                 mpath = mesh_path_lookup(sdata, target_addr);
 625                 if (mpath) {
 626                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 627                                         SN_LT(mpath->sn, target_sn)) {
 628                                 mpath->sn = target_sn;
 629                                 mpath->flags |= MESH_PATH_SN_VALID;
 630                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 631                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 632                                 reply = true;
 633                                 target_metric = mpath->metric;
 634                                 target_sn = mpath->sn;
 635                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 636                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 637                         }
 638                 }
 639                 rcu_read_unlock();
 640         }
 641
 642         if (reply) {
 643                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 644                 ttl = ifmsh->mshcfg.element_ttl;
 645                 if (ttl != 0) {
 646                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 647                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 648                                                orig_sn, 0, target_addr,
 649                                                target_sn, mgmt->sa, 0, ttl,
 650                                                lifetime, target_metric, 0,
 651                                                sdata);
 652                 } else {
 653                         ifmsh->mshstats.dropped_frames_ttl++;
 654                 }
 655         }
 656
 657         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 658                 u32 preq_id;
 659                 u8 hopcount;
 660
 661                 ttl = PREQ_IE_TTL(preq_elem);
 662                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 663                 if (ttl <= 1) {
 664                         ifmsh->mshstats.dropped_frames_ttl++;
 665                         return;
 666                 }
 667                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 668                 --ttl;
 669                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 670                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 671                 da = (mpath && mpath->is_root) ?
 672                         mpath->rann_snd_addr : broadcast_addr;
 673
 674                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 675                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 676                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 677                 }
 678
 679                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 680                                        orig_sn, target_flags, target_addr,
 681                                        target_sn, da, hopcount, ttl, lifetime,
 682                                        orig_metric, preq_id, sdata);
 683                 if (!is_multicast_ether_addr(da))
 684                         ifmsh->mshstats.fwded_unicast++;
 685                 else
 686                         ifmsh->mshstats.fwded_mcast++;
 687                 ifmsh->mshstats.fwded_frames++;
 688         }
 689 }
 690
 691
 692 static inline struct sta_info *
 693 next_hop_deref_protected(struct mesh_path *mpath)
 694 {
 695         return rcu_dereference_protected(mpath->next_hop,
 696                                          lockdep_is_held(&mpath->state_lock));
 697 }
 698
 699
 700 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 701                                     struct ieee80211_mgmt *mgmt,
 702                                     const u8 *prep_elem, u32 metric)
 703 {
 704         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 705         struct mesh_path *mpath;
 706         const u8 *target_addr, *orig_addr;
 707         u8 ttl, hopcount, flags;
 708         u8 next_hop[ETH_ALEN];
 709         u32 target_sn, orig_sn, lifetime;
 710
 711         mhwmp_dbg(sdata, "received PREP from %pM\n",
 712                   PREP_IE_TARGET_ADDR(prep_elem));
 713
 714         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 715         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 716                 /* destination, no forwarding required */
 717                 return;
 718
 719         if (!ifmsh->mshcfg.dot11MeshForwarding)
 720                 return;
 721
 722         ttl = PREP_IE_TTL(prep_elem);
 723         if (ttl <= 1) {
 724                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 725                 return;
 726         }
 727
 728         rcu_read_lock();
 729         mpath = mesh_path_lookup(sdata, orig_addr);
 730         if (mpath)
 731                 spin_lock_bh(&mpath->state_lock);
 732         else
 733                 goto fail;
 734         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 735                 spin_unlock_bh(&mpath->state_lock);
 736                 goto fail;
 737         }
 738         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 739         spin_unlock_bh(&mpath->state_lock);
 740         --ttl;
 741         flags = PREP_IE_FLAGS(prep_elem);
 742         lifetime = PREP_IE_LIFETIME(prep_elem);
 743         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 744         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 745         target_sn = PREP_IE_TARGET_SN(prep_elem);
 746         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 747
 748         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 749                                target_addr, target_sn, next_hop, hopcount,
 750                                ttl, lifetime, metric, 0, sdata);
 751         rcu_read_unlock();
 752
 753         sdata->u.mesh.mshstats.fwded_unicast++;
 754         sdata->u.mesh.mshstats.fwded_frames++;
 755         return;
 756
 757 fail:
 758         rcu_read_unlock();
 759         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 760 }
 761
 762 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 763                                     struct ieee80211_mgmt *mgmt,
 764                                     const u8 *perr_elem)
 765 {
 766         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 767         struct mesh_path *mpath;
 768         u8 ttl;
 769         const u8 *ta, *target_addr;
 770         u32 target_sn;
 771         u16 target_rcode;
 772
 773         ta = mgmt->sa;
 774         ttl = PERR_IE_TTL(perr_elem);
 775         if (ttl <= 1) {
 776                 ifmsh->mshstats.dropped_frames_ttl++;
 777                 return;
 778         }
 779         ttl--;
 780         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 781         target_sn = PERR_IE_TARGET_SN(perr_elem);
 782         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 783
 784         rcu_read_lock();
 785         mpath = mesh_path_lookup(sdata, target_addr);
 786         if (mpath) {
 787                 struct sta_info *sta;
 788
 789                 spin_lock_bh(&mpath->state_lock);
 790                 sta = next_hop_deref_protected(mpath);
 791                 if (mpath->flags & MESH_PATH_ACTIVE &&
 792                     ether_addr_equal(ta, sta->sta.addr) &&
 793                     !(mpath->flags & MESH_PATH_FIXED) &&
 794                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 795                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 796                         mpath->flags &= ~MESH_PATH_ACTIVE;
 797                         if (target_sn != 0)
 798                                 mpath->sn = target_sn;
 799                         else
 800                                 mpath->sn += 1;
 801                         spin_unlock_bh(&mpath->state_lock);
 802                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 803                                 goto endperr;
 804                         mesh_path_error_tx(sdata, ttl, target_addr,
 805                                            target_sn, target_rcode,
 806                                            broadcast_addr);
 807                 } else
 808                         spin_unlock_bh(&mpath->state_lock);
 809         }
 810 endperr:
 811         rcu_read_unlock();
 812 }
 813
 814 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 815                                     struct ieee80211_mgmt *mgmt,
 816                                     const struct ieee80211_rann_ie *rann)
 817 {
 818         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 819         struct ieee80211_local *local = sdata->local;
 820         struct sta_info *sta;
 821         struct mesh_path *mpath;
 822         u8 ttl, flags, hopcount;
 823         const u8 *orig_addr;
 824         u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
 825         bool root_is_gate;
 826
 827         ttl = rann->rann_ttl;
 828         flags = rann->rann_flags;
 829         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 830         orig_addr = rann->rann_addr;
 831         orig_sn = le32_to_cpu(rann->rann_seq);
 832         interval = le32_to_cpu(rann->rann_interval);
 833         hopcount = rann->rann_hopcount;
 834         hopcount++;
 835         orig_metric = le32_to_cpu(rann->rann_metric);
 836
 837         /*  Ignore our own RANNs */
 838         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 839                 return;
 840
 841         mhwmp_dbg(sdata,
 842                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 843                   orig_addr, mgmt->sa, root_is_gate);
 844
 845         rcu_read_lock();
 846         sta = sta_info_get(sdata, mgmt->sa);
 847         if (!sta) {
 848                 rcu_read_unlock();
 849                 return;
 850         }
 851
 852         last_hop_metric = airtime_link_metric_get(local, sta);
 853         new_metric = orig_metric + last_hop_metric;
 854         if (new_metric < orig_metric)
 855                 new_metric = MAX_METRIC;
 856
 857         mpath = mesh_path_lookup(sdata, orig_addr);
 858         if (!mpath) {
 859                 mpath = mesh_path_add(sdata, orig_addr);
 860                 if (IS_ERR(mpath)) {
 861                         rcu_read_unlock();
 862                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 863                         return;
 864                 }
 865         }
 866
 867         if (!(SN_LT(mpath->sn, orig_sn)) &&
 868             !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
 869                 rcu_read_unlock();
 870                 return;
 871         }
 872
 873         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 874              (time_after(jiffies, mpath->last_preq_to_root +
 875                                   root_path_confirmation_jiffies(sdata)) ||
 876              time_before(jiffies, mpath->last_preq_to_root))) &&
 877              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 878                 mhwmp_dbg(sdata,
 879                           "time to refresh root mpath %pM\n",
 880                           orig_addr);
 881                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 882                 mpath->last_preq_to_root = jiffies;
 883         }
 884
 885         mpath->sn = orig_sn;
 886         mpath->rann_metric = new_metric;
 887         mpath->is_root = true;
 888         /* Recording RANNs sender address to send individually
 889          * addressed PREQs destined for root mesh STA */
 890         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 891
 892         if (root_is_gate)
 893                 mesh_path_add_gate(mpath);
 894
 895         if (ttl <= 1) {
 896                 ifmsh->mshstats.dropped_frames_ttl++;
 897                 rcu_read_unlock();
 898                 return;
 899         }
 900         ttl--;
 901
 902         if (ifmsh->mshcfg.dot11MeshForwarding) {
 903                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 904                                        orig_sn, 0, NULL, 0, broadcast_addr,
 905                                        hopcount, ttl, interval,
 906                                        new_metric, 0, sdata);
 907         }
 908
 909         rcu_read_unlock();
 910 }
 911
 912
 913 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 914                             struct ieee80211_mgmt *mgmt, size_t len)
 915 {
 916         struct ieee802_11_elems *elems;
 917         size_t baselen;
 918         u32 path_metric;
 919         struct sta_info *sta;
 920
 921         /* need action_code */
 922         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 923                 return;
 924
 925         rcu_read_lock();
 926         sta = sta_info_get(sdata, mgmt->sa);
 927         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 928                 rcu_read_unlock();
 929                 return;
 930         }
 931         rcu_read_unlock();
 932
 933         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 934         elems = ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 935                                        len - baselen, false, NULL);
 936         if (!elems)
 937                 return;
 938
 939         if (elems->preq) {
 940                 if (elems->preq_len != 37)
 941                         /* Right now we support just 1 destination and no AE */
 942                         goto free;
 943                 path_metric = hwmp_route_info_get(sdata, mgmt, elems->preq,
 944                                                   MPATH_PREQ);
 945                 if (path_metric)
 946                         hwmp_preq_frame_process(sdata, mgmt, elems->preq,
 947                                                 path_metric);
 948         }
 949         if (elems->prep) {
 950                 if (elems->prep_len != 31)
 951                         /* Right now we support no AE */
 952                         goto free;
 953                 path_metric = hwmp_route_info_get(sdata, mgmt, elems->prep,
 954                                                   MPATH_PREP);
 955                 if (path_metric)
 956                         hwmp_prep_frame_process(sdata, mgmt, elems->prep,
 957                                                 path_metric);
 958         }
 959         if (elems->perr) {
 960                 if (elems->perr_len != 15)
 961                         /* Right now we support only one destination per PERR */
 962                         goto free;
 963                 hwmp_perr_frame_process(sdata, mgmt, elems->perr);
 964         }
 965         if (elems->rann)
 966                 hwmp_rann_frame_process(sdata, mgmt, elems->rann);
 967 free:
 968         kfree(elems);
 969 }
 970
 971 /**
 972  * mesh_queue_preq - queue a PREQ to a given destination
 973  *
 974  * @mpath: mesh path to discover
 975  * @flags: special attributes of the PREQ to be sent
 976  *
 977  * Locking: the function must be called from within a rcu read lock block.
 978  *
 979  */
 980 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 981 {
 982         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 983         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 984         struct mesh_preq_queue *preq_node;
 985
 986         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 987         if (!preq_node) {
 988                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 989                 return;
 990         }
 991
 992         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 993         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 994                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 995                 kfree(preq_node);
 996                 if (printk_ratelimit())
 997                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 998                 return;
 999         }
1000
1001         spin_lock(&mpath->state_lock);
1002         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
1003                 spin_unlock(&mpath->state_lock);
1004                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1005                 kfree(preq_node);
1006                 return;
1007         }
1008
1009         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
1010         preq_node->flags = flags;
1011
1012         mpath->flags |= MESH_PATH_REQ_QUEUED;
1013         spin_unlock(&mpath->state_lock);
1014
1015         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
1016         ++ifmsh->preq_queue_len;
1017         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1018
1019         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
1020                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1021
1022         else if (time_before(jiffies, ifmsh->last_preq)) {
1023                 /* avoid long wait if did not send preqs for a long time
1024                  * and jiffies wrapped around
1025                  */
1026                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1027                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1028         } else
1029                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1030                                                 min_preq_int_jiff(sdata));
1031 }
1032
1033 /**
1034  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1035  *
1036  * @sdata: local mesh subif
1037  */
1038 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1039 {
1040         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1041         struct mesh_preq_queue *preq_node;
1042         struct mesh_path *mpath;
1043         u8 ttl, target_flags = 0;
1044         const u8 *da;
1045         u32 lifetime;
1046
1047         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1048         if (!ifmsh->preq_queue_len ||
1049                 time_before(jiffies, ifmsh->last_preq +
1050                                 min_preq_int_jiff(sdata))) {
1051                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1052                 return;
1053         }
1054
1055         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1056                         struct mesh_preq_queue, list);
1057         list_del(&preq_node->list);
1058         --ifmsh->preq_queue_len;
1059         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1060
1061         rcu_read_lock();
1062         mpath = mesh_path_lookup(sdata, preq_node->dst);
1063         if (!mpath)
1064                 goto enddiscovery;
1065
1066         spin_lock_bh(&mpath->state_lock);
1067         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1068                 spin_unlock_bh(&mpath->state_lock);
1069                 goto enddiscovery;
1070         }
1071         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1072         if (preq_node->flags & PREQ_Q_F_START) {
1073                 if (mpath->flags & MESH_PATH_RESOLVING) {
1074                         spin_unlock_bh(&mpath->state_lock);
1075                         goto enddiscovery;
1076                 } else {
1077                         mpath->flags &= ~MESH_PATH_RESOLVED;
1078                         mpath->flags |= MESH_PATH_RESOLVING;
1079                         mpath->discovery_retries = 0;
1080                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1081                 }
1082         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1083                         mpath->flags & MESH_PATH_RESOLVED) {
1084                 mpath->flags &= ~MESH_PATH_RESOLVING;
1085                 spin_unlock_bh(&mpath->state_lock);
1086                 goto enddiscovery;
1087         }
1088
1089         ifmsh->last_preq = jiffies;
1090
1091         if (time_after(jiffies, ifmsh->last_sn_update +
1092                                 net_traversal_jiffies(sdata)) ||
1093             time_before(jiffies, ifmsh->last_sn_update)) {
1094                 ++ifmsh->sn;
1095                 sdata->u.mesh.last_sn_update = jiffies;
1096         }
1097         lifetime = default_lifetime(sdata);
1098         ttl = sdata->u.mesh.mshcfg.element_ttl;
1099         if (ttl == 0) {
1100                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1101                 spin_unlock_bh(&mpath->state_lock);
1102                 goto enddiscovery;
1103         }
1104
1105         if (preq_node->flags & PREQ_Q_F_REFRESH)
1106                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1107         else
1108                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1109
1110         spin_unlock_bh(&mpath->state_lock);
1111         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1112         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1113                                target_flags, mpath->dst, mpath->sn, da, 0,
1114                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1115
1116         spin_lock_bh(&mpath->state_lock);
1117         if (!(mpath->flags & MESH_PATH_DELETED))
1118                 mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1119         spin_unlock_bh(&mpath->state_lock);
1120
1121 enddiscovery:
1122         rcu_read_unlock();
1123         kfree(preq_node);
1124 }
1125
1126 /**
1127  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1128  *
1129  * @skb: 802.11 frame to be sent
1130  * @sdata: network subif the frame will be sent through
1131  *
1132  * Lookup next hop for given skb and start path discovery if no
1133  * forwarding information is found.
1134  *
1135  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1136  * skb is freed here if no mpath could be allocated.
1137  */
1138 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1139                          struct sk_buff *skb)
1140 {
1141         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1142         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1143         struct mesh_path *mpath;
1144         struct sk_buff *skb_to_free = NULL;
1145         u8 *target_addr = hdr->addr3;
1146
1147         /* Nulls are only sent to peers for PS and should be pre-addressed */
1148         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1149                 return 0;
1150
1151         /* Allow injected packets to bypass mesh routing */
1152         if (info->control.flags & IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP)
1153                 return 0;
1154
1155         if (!mesh_nexthop_lookup(sdata, skb))
1156                 return 0;
1157
1158         /* no nexthop found, start resolving */
1159         mpath = mesh_path_lookup(sdata, target_addr);
1160         if (!mpath) {
1161                 mpath = mesh_path_add(sdata, target_addr);
1162                 if (IS_ERR(mpath)) {
1163                         mesh_path_discard_frame(sdata, skb);
1164                         return PTR_ERR(mpath);
1165                 }
1166         }
1167
1168         if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1169             mesh_path_sel_is_hwmp(sdata))
1170                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1171
1172         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1173                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1174
1175         info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
1176         ieee80211_set_qos_hdr(sdata, skb);
1177         skb_queue_tail(&mpath->frame_queue, skb);
1178         if (skb_to_free)
1179                 mesh_path_discard_frame(sdata, skb_to_free);
1180
1181         return -ENOENT;
1182 }
1183
1184 /**
1185  * mesh_nexthop_lookup_nolearn - try to set next hop without path discovery
1186  * @skb: 802.11 frame to be sent
1187  * @sdata: network subif the frame will be sent through
1188  *
1189  * Check if the meshDA (addr3) of a unicast frame is a direct neighbor.
1190  * And if so, set the RA (addr1) to it to transmit to this node directly,
1191  * avoiding PREQ/PREP path discovery.
1192  *
1193  * Returns: 0 if the next hop was found and -ENOENT otherwise.
1194  */
1195 static int mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data *sdata,
1196                                        struct sk_buff *skb)
1197 {
1198         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1199         struct sta_info *sta;
1200
1201         if (is_multicast_ether_addr(hdr->addr1))
1202                 return -ENOENT;
1203
1204         rcu_read_lock();
1205         sta = sta_info_get(sdata, hdr->addr3);
1206
1207         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
1208                 rcu_read_unlock();
1209                 return -ENOENT;
1210         }
1211         rcu_read_unlock();
1212
1213         memcpy(hdr->addr1, hdr->addr3, ETH_ALEN);
1214         memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1215         return 0;
1216 }
1217
1218 /**
1219  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1220  * this function is considered "using" the associated mpath, so preempt a path
1221  * refresh if this mpath expires soon.
1222  *
1223  * @skb: 802.11 frame to be sent
1224  * @sdata: network subif the frame will be sent through
1225  *
1226  * Returns: 0 if the next hop was found. Nonzero otherwise.
1227  */
1228 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1229                         struct sk_buff *skb)
1230 {
1231         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1232         struct mesh_path *mpath;
1233         struct sta_info *next_hop;
1234         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1235         u8 *target_addr = hdr->addr3;
1236
1237         if (ifmsh->mshcfg.dot11MeshNolearn &&
1238             !mesh_nexthop_lookup_nolearn(sdata, skb))
1239                 return 0;
1240
1241         mpath = mesh_path_lookup(sdata, target_addr);
1242         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1243                 return -ENOENT;
1244
1245         if (time_after(jiffies,
1246                        mpath->exp_time -
1247                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1248             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1249             !(mpath->flags & MESH_PATH_RESOLVING) &&
1250             !(mpath->flags & MESH_PATH_FIXED))
1251                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1252
1253         next_hop = rcu_dereference(mpath->next_hop);
1254         if (next_hop) {
1255                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1256                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1257                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1258                 return 0;
1259         }
1260
1261         return -ENOENT;
1262 }
1263
1264 void mesh_path_timer(struct timer_list *t)
1265 {
1266         struct mesh_path *mpath = from_timer(mpath, t, timer);
1267         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1268         int ret;
1269
1270         if (sdata->local->quiescing)
1271                 return;
1272
1273         spin_lock_bh(&mpath->state_lock);
1274         if (mpath->flags & MESH_PATH_RESOLVED ||
1275                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1276                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1277                 spin_unlock_bh(&mpath->state_lock);
1278         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1279                 ++mpath->discovery_retries;
1280                 mpath->discovery_timeout *= 2;
1281                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1282                 spin_unlock_bh(&mpath->state_lock);
1283                 mesh_queue_preq(mpath, 0);
1284         } else {
1285                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1286                                   MESH_PATH_RESOLVED |
1287                                   MESH_PATH_REQ_QUEUED);
1288                 mpath->exp_time = jiffies;
1289                 spin_unlock_bh(&mpath->state_lock);
1290                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1291                         ret = mesh_path_send_to_gates(mpath);
1292                         if (ret)
1293                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1294                 } else
1295                         mesh_path_flush_pending(mpath);
1296         }
1297 }
1298
1299 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1300 {
1301         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1302         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1303         u8 flags, target_flags = 0;
1304
1305         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1306                         ? RANN_FLAG_IS_GATE : 0;
1307
1308         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1309         case IEEE80211_PROACTIVE_RANN:
1310                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1311                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1312                                        0, ifmsh->mshcfg.element_ttl,
1313                                        interval, 0, 0, sdata);
1314                 break;
1315         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1316                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1317                 fallthrough;
1318         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1319                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1320                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1321                                 IEEE80211_PREQ_USN_FLAG;
1322                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1323                                        ++ifmsh->sn, target_flags,
1324                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1325                                        0, ifmsh->mshcfg.element_ttl, interval,
1326                                        0, ifmsh->preq_id++, sdata);
1327                 break;
1328         default:
1329                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1330                 return;
1331         }
1332 }