net/mac80211/mesh_hwmp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2008, 2009 open80211s Ltd.
   4  * Copyright (C) 2019 Intel Corporation
   5  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   6  */
   7
   8 #include <linux/slab.h>
   9 #include <linux/etherdevice.h>
  10 #include <asm/unaligned.h>
  11 #include "wme.h"
  12 #include "mesh.h"
  13
  14 #define TEST_FRAME_LEN  8192
  15 #define MAX_METRIC      0xffffffff
  16 #define ARITH_SHIFT     8
  17 #define LINK_FAIL_THRESH 95
  18
  19 #define MAX_PREQ_QUEUE_LEN      64
  20
  21 static void mesh_queue_preq(struct mesh_path *, u8);
  22
  23 static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
  24 {
  25         if (ae)
  26                 offset += 6;
  27         return get_unaligned_le32(preq_elem + offset);
  28 }
  29
  30 static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
  31 {
  32         if (ae)
  33                 offset += 6;
  34         return get_unaligned_le16(preq_elem + offset);
  35 }
  36
  37 /* HWMP IE processing macros */
  38 #define AE_F                    (1<<6)
  39 #define AE_F_SET(x)             (*x & AE_F)
  40 #define PREQ_IE_FLAGS(x)        (*(x))
  41 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  42 #define PREQ_IE_TTL(x)          (*(x + 2))
  43 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  44 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  45 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  46 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  47 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  48 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  49 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  50 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  51
  52
  53 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  54 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  55 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  56 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  57 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  58 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  59 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  60 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  61 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  62
  63 #define PERR_IE_TTL(x)          (*(x))
  64 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  65 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  66 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  67 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  68
  69 #define MSEC_TO_TU(x) (x*1000/1024)
  70 #define SN_GT(x, y) ((s32)(y - x) < 0)
  71 #define SN_LT(x, y) ((s32)(x - y) < 0)
  72 #define MAX_SANE_SN_DELTA 32
  73
  74 static inline u32 SN_DELTA(u32 x, u32 y)
  75 {
  76         return x >= y ? x - y : y - x;
  77 }
  78
  79 #define net_traversal_jiffies(s) \
  80         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  81 #define default_lifetime(s) \
  82         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  83 #define min_preq_int_jiff(s) \
  84         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  85 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  86 #define disc_timeout_jiff(s) \
  87         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  88 #define root_path_confirmation_jiffies(s) \
  89         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  90
  91 enum mpath_frame_type {
  92         MPATH_PREQ = 0,
  93         MPATH_PREP,
  94         MPATH_PERR,
  95         MPATH_RANN
  96 };
  97
  98 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
  99
 100 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 101                                   const u8 *orig_addr, u32 orig_sn,
 102                                   u8 target_flags, const u8 *target,
 103                                   u32 target_sn, const u8 *da,
 104                                   u8 hop_count, u8 ttl,
 105                                   u32 lifetime, u32 metric, u32 preq_id,
 106                                   struct ieee80211_sub_if_data *sdata)
 107 {
 108         struct ieee80211_local *local = sdata->local;
 109         struct sk_buff *skb;
 110         struct ieee80211_mgmt *mgmt;
 111         u8 *pos, ie_len;
 112         int hdr_len = offsetofend(struct ieee80211_mgmt,
 113                                   u.action.u.mesh_action);
 114
 115         skb = dev_alloc_skb(local->tx_headroom +
 116                             hdr_len +
 117                             2 + 37); /* max HWMP IE */
 118         if (!skb)
 119                 return -1;
 120         skb_reserve(skb, local->tx_headroom);
 121         mgmt = skb_put_zero(skb, hdr_len);
 122         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 123                                           IEEE80211_STYPE_ACTION);
 124
 125         memcpy(mgmt->da, da, ETH_ALEN);
 126         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 127         /* BSSID == SA */
 128         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 129         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 130         mgmt->u.action.u.mesh_action.action_code =
 131                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 132
 133         switch (action) {
 134         case MPATH_PREQ:
 135                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 136                 ie_len = 37;
 137                 pos = skb_put(skb, 2 + ie_len);
 138                 *pos++ = WLAN_EID_PREQ;
 139                 break;
 140         case MPATH_PREP:
 141                 mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
 142                 ie_len = 31;
 143                 pos = skb_put(skb, 2 + ie_len);
 144                 *pos++ = WLAN_EID_PREP;
 145                 break;
 146         case MPATH_RANN:
 147                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 148                 ie_len = sizeof(struct ieee80211_rann_ie);
 149                 pos = skb_put(skb, 2 + ie_len);
 150                 *pos++ = WLAN_EID_RANN;
 151                 break;
 152         default:
 153                 kfree_skb(skb);
 154                 return -ENOTSUPP;
 155         }
 156         *pos++ = ie_len;
 157         *pos++ = flags;
 158         *pos++ = hop_count;
 159         *pos++ = ttl;
 160         if (action == MPATH_PREP) {
 161                 memcpy(pos, target, ETH_ALEN);
 162                 pos += ETH_ALEN;
 163                 put_unaligned_le32(target_sn, pos);
 164                 pos += 4;
 165         } else {
 166                 if (action == MPATH_PREQ) {
 167                         put_unaligned_le32(preq_id, pos);
 168                         pos += 4;
 169                 }
 170                 memcpy(pos, orig_addr, ETH_ALEN);
 171                 pos += ETH_ALEN;
 172                 put_unaligned_le32(orig_sn, pos);
 173                 pos += 4;
 174         }
 175         put_unaligned_le32(lifetime, pos); /* interval for RANN */
 176         pos += 4;
 177         put_unaligned_le32(metric, pos);
 178         pos += 4;
 179         if (action == MPATH_PREQ) {
 180                 *pos++ = 1; /* destination count */
 181                 *pos++ = target_flags;
 182                 memcpy(pos, target, ETH_ALEN);
 183                 pos += ETH_ALEN;
 184                 put_unaligned_le32(target_sn, pos);
 185                 pos += 4;
 186         } else if (action == MPATH_PREP) {
 187                 memcpy(pos, orig_addr, ETH_ALEN);
 188                 pos += ETH_ALEN;
 189                 put_unaligned_le32(orig_sn, pos);
 190                 pos += 4;
 191         }
 192
 193         ieee80211_tx_skb(sdata, skb);
 194         return 0;
 195 }
 196
 197
 198 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 199  *  headroom in case the frame is encrypted. */
 200 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 201                 struct sk_buff *skb)
 202 {
 203         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 204         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 205
 206         skb_reset_mac_header(skb);
 207         skb_reset_network_header(skb);
 208         skb_reset_transport_header(skb);
 209
 210         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 211         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 212         skb->priority = 7;
 213
 214         info->control.vif = &sdata->vif;
 215         info->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                             sdata->encrypt_headroom +
 251                             IEEE80211_ENCRYPT_TAILROOM +
 252                             hdr_len +
 253                             2 + 15 /* PERR IE */);
 254         if (!skb)
 255                 return -1;
 256         skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom);
 257         mgmt = skb_put_zero(skb, hdr_len);
 258         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 259                                           IEEE80211_STYPE_ACTION);
 260
 261         memcpy(mgmt->da, ra, ETH_ALEN);
 262         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 263         /* BSSID == SA */
 264         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 265         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 266         mgmt->u.action.u.mesh_action.action_code =
 267                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 268         ie_len = 15;
 269         pos = skb_put(skb, 2 + ie_len);
 270         *pos++ = WLAN_EID_PERR;
 271         *pos++ = ie_len;
 272         /* ttl */
 273         *pos++ = ttl;
 274         /* number of destinations */
 275         *pos++ = 1;
 276         /* Flags field has AE bit only as defined in
 277          * sec 8.4.2.117 IEEE802.11-2012
 278          */
 279         *pos = 0;
 280         pos++;
 281         memcpy(pos, target, ETH_ALEN);
 282         pos += ETH_ALEN;
 283         put_unaligned_le32(target_sn, pos);
 284         pos += 4;
 285         put_unaligned_le16(target_rcode, pos);
 286
 287         /* see note in function header */
 288         prepare_frame_for_deferred_tx(sdata, skb);
 289         ifmsh->next_perr = TU_TO_EXP_TIME(
 290                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 291         ieee80211_add_pending_skb(local, skb);
 292         return 0;
 293 }
 294
 295 void ieee80211s_update_metric(struct ieee80211_local *local,
 296                               struct sta_info *sta,
 297                               struct ieee80211_tx_status *st)
 298 {
 299         struct ieee80211_tx_info *txinfo = st->info;
 300         int failed;
 301         struct rate_info rinfo;
 302
 303         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 304
 305         /* moving average, scaled to 100.
 306          * feed failure as 100 and success as 0
 307          */
 308         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
 309         if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
 310                         LINK_FAIL_THRESH)
 311                 mesh_plink_broken(sta);
 312
 313         sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
 314         ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg,
 315                                   cfg80211_calculate_bitrate(&rinfo));
 316 }
 317
 318 u32 airtime_link_metric_get(struct ieee80211_local *local,
 319                             struct sta_info *sta)
 320 {
 321         /* This should be adjusted for each device */
 322         int device_constant = 1 << ARITH_SHIFT;
 323         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 324         int s_unit = 1 << ARITH_SHIFT;
 325         int rate, err;
 326         u32 tx_time, estimated_retx;
 327         u64 result;
 328         unsigned long fail_avg =
 329                 ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
 330
 331         if (sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 332                 return MAX_METRIC;
 333
 334         /* Try to get rate based on HW/SW RC algorithm.
 335          * Rate is returned in units of Kbps, correct this
 336          * to comply with airtime calculation units
 337          * Round up in case we get rate < 100Kbps
 338          */
 339         rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
 340
 341         if (rate) {
 342                 err = 0;
 343         } else {
 344                 if (fail_avg > LINK_FAIL_THRESH)
 345                         return MAX_METRIC;
 346
 347                 rate = ewma_mesh_tx_rate_avg_read(&sta->mesh->tx_rate_avg);
 348                 if (WARN_ON(!rate))
 349                         return MAX_METRIC;
 350
 351                 err = (fail_avg << ARITH_SHIFT) / 100;
 352         }
 353
 354         /* bitrate is in units of 100 Kbps, while we need rate in units of
 355          * 1Mbps. This will be corrected on tx_time computation.
 356          */
 357         tx_time = (device_constant + 10 * test_frame_len / rate);
 358         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 359         result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
 360         return (u32)result;
 361 }
 362
 363 /**
 364  * hwmp_route_info_get - Update routing info to originator and transmitter
 365  *
 366  * @sdata: local mesh subif
 367  * @mgmt: mesh management frame
 368  * @hwmp_ie: hwmp information element (PREP or PREQ)
 369  * @action: type of hwmp ie
 370  *
 371  * This function updates the path routing information to the originator and the
 372  * transmitter of a HWMP PREQ or PREP frame.
 373  *
 374  * Returns: metric to frame originator or 0 if the frame should not be further
 375  * processed
 376  *
 377  * Notes: this function is the only place (besides user-provided info) where
 378  * path routing information is updated.
 379  */
 380 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 381                                struct ieee80211_mgmt *mgmt,
 382                                const u8 *hwmp_ie, enum mpath_frame_type action)
 383 {
 384         struct ieee80211_local *local = sdata->local;
 385         struct mesh_path *mpath;
 386         struct sta_info *sta;
 387         bool fresh_info;
 388         const u8 *orig_addr, *ta;
 389         u32 orig_sn, orig_metric;
 390         unsigned long orig_lifetime, exp_time;
 391         u32 last_hop_metric, new_metric;
 392         bool process = true;
 393         u8 hopcount;
 394
 395         rcu_read_lock();
 396         sta = sta_info_get(sdata, mgmt->sa);
 397         if (!sta) {
 398                 rcu_read_unlock();
 399                 return 0;
 400         }
 401
 402         last_hop_metric = airtime_link_metric_get(local, sta);
 403         /* Update and check originator routing info */
 404         fresh_info = true;
 405
 406         switch (action) {
 407         case MPATH_PREQ:
 408                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 409                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 410                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 411                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 412                 hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1;
 413                 break;
 414         case MPATH_PREP:
 415                 /* Originator here refers to the MP that was the target in the
 416                  * Path Request. We divert from the nomenclature in the draft
 417                  * so that we can easily use a single function to gather path
 418                  * information from both PREQ and PREP frames.
 419                  */
 420                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 421                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 422                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 423                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 424                 hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1;
 425                 break;
 426         default:
 427                 rcu_read_unlock();
 428                 return 0;
 429         }
 430         new_metric = orig_metric + last_hop_metric;
 431         if (new_metric < orig_metric)
 432                 new_metric = MAX_METRIC;
 433         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 434
 435         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 436                 /* This MP is the originator, we are not interested in this
 437                  * frame, except for updating transmitter's path info.
 438                  */
 439                 process = false;
 440                 fresh_info = false;
 441         } else {
 442                 mpath = mesh_path_lookup(sdata, orig_addr);
 443                 if (mpath) {
 444                         spin_lock_bh(&mpath->state_lock);
 445                         if (mpath->flags & MESH_PATH_FIXED)
 446                                 fresh_info = false;
 447                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 448                             (mpath->flags & MESH_PATH_SN_VALID)) {
 449                                 if (SN_GT(mpath->sn, orig_sn) ||
 450                                     (mpath->sn == orig_sn &&
 451                                      (rcu_access_pointer(mpath->next_hop) !=
 452                                                       sta ?
 453                                               mult_frac(new_metric, 10, 9) :
 454                                               new_metric) >= mpath->metric)) {
 455                                         process = false;
 456                                         fresh_info = false;
 457                                 }
 458                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 459                                 bool have_sn, newer_sn, bounced;
 460
 461                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 462                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 463                                 bounced = have_sn &&
 464                                           (SN_DELTA(orig_sn, mpath->sn) >
 465                                                         MAX_SANE_SN_DELTA);
 466
 467                                 if (!have_sn || newer_sn) {
 468                                         /* if SN is newer than what we had
 469                                          * then we can take it */;
 470                                 } else if (bounced) {
 471                                         /* if SN is way different than what
 472                                          * we had then assume the other side
 473                                          * rebooted or restarted */;
 474                                 } else {
 475                                         process = false;
 476                                         fresh_info = false;
 477                                 }
 478                         }
 479                 } else {
 480                         mpath = mesh_path_add(sdata, orig_addr);
 481                         if (IS_ERR(mpath)) {
 482                                 rcu_read_unlock();
 483                                 return 0;
 484                         }
 485                         spin_lock_bh(&mpath->state_lock);
 486                 }
 487
 488                 if (fresh_info) {
 489                         if (rcu_access_pointer(mpath->next_hop) != sta)
 490                                 mpath->path_change_count++;
 491                         mesh_path_assign_nexthop(mpath, sta);
 492                         mpath->flags |= MESH_PATH_SN_VALID;
 493                         mpath->metric = new_metric;
 494                         mpath->sn = orig_sn;
 495                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 496                                           ?  mpath->exp_time : exp_time;
 497                         mpath->hop_count = hopcount;
 498                         mesh_path_activate(mpath);
 499                         spin_unlock_bh(&mpath->state_lock);
 500                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 501                         /* init it at a low value - 0 start is tricky */
 502                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 503                         mesh_path_tx_pending(mpath);
 504                         /* draft says preq_id should be saved to, but there does
 505                          * not seem to be any use for it, skipping by now
 506                          */
 507                 } else
 508                         spin_unlock_bh(&mpath->state_lock);
 509         }
 510
 511         /* Update and check transmitter routing info */
 512         ta = mgmt->sa;
 513         if (ether_addr_equal(orig_addr, ta))
 514                 fresh_info = false;
 515         else {
 516                 fresh_info = true;
 517
 518                 mpath = mesh_path_lookup(sdata, ta);
 519                 if (mpath) {
 520                         spin_lock_bh(&mpath->state_lock);
 521                         if ((mpath->flags & MESH_PATH_FIXED) ||
 522                             ((mpath->flags & MESH_PATH_ACTIVE) &&
 523                              ((rcu_access_pointer(mpath->next_hop) != sta ?
 524                                        mult_frac(last_hop_metric, 10, 9) :
 525                                        last_hop_metric) > mpath->metric)))
 526                                 fresh_info = false;
 527                 } else {
 528                         mpath = mesh_path_add(sdata, ta);
 529                         if (IS_ERR(mpath)) {
 530                                 rcu_read_unlock();
 531                                 return 0;
 532                         }
 533                         spin_lock_bh(&mpath->state_lock);
 534                 }
 535
 536                 if (fresh_info) {
 537                         if (rcu_access_pointer(mpath->next_hop) != sta)
 538                                 mpath->path_change_count++;
 539                         mesh_path_assign_nexthop(mpath, sta);
 540                         mpath->metric = last_hop_metric;
 541                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 542                                           ?  mpath->exp_time : exp_time;
 543                         mpath->hop_count = 1;
 544                         mesh_path_activate(mpath);
 545                         spin_unlock_bh(&mpath->state_lock);
 546                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 547                         /* init it at a low value - 0 start is tricky */
 548                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 549                         mesh_path_tx_pending(mpath);
 550                 } else
 551                         spin_unlock_bh(&mpath->state_lock);
 552         }
 553
 554         rcu_read_unlock();
 555
 556         return process ? new_metric : 0;
 557 }
 558
 559 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 560                                     struct ieee80211_mgmt *mgmt,
 561                                     const u8 *preq_elem, u32 orig_metric)
 562 {
 563         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 564         struct mesh_path *mpath = NULL;
 565         const u8 *target_addr, *orig_addr;
 566         const u8 *da;
 567         u8 target_flags, ttl, flags;
 568         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 569         bool reply = false;
 570         bool forward = true;
 571         bool root_is_gate;
 572
 573         /* Update target SN, if present */
 574         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 575         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 576         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 577         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 578         target_flags = PREQ_IE_TARGET_F(preq_elem);
 579         /* Proactive PREQ gate announcements */
 580         flags = PREQ_IE_FLAGS(preq_elem);
 581         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 582
 583         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 584
 585         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 586                 mhwmp_dbg(sdata, "PREQ is for us\n");
 587                 forward = false;
 588                 reply = true;
 589                 target_metric = 0;
 590
 591                 if (SN_GT(target_sn, ifmsh->sn))
 592                         ifmsh->sn = target_sn;
 593
 594                 if (time_after(jiffies, ifmsh->last_sn_update +
 595                                         net_traversal_jiffies(sdata)) ||
 596                     time_before(jiffies, ifmsh->last_sn_update)) {
 597                         ++ifmsh->sn;
 598                         ifmsh->last_sn_update = jiffies;
 599                 }
 600                 target_sn = ifmsh->sn;
 601         } else if (is_broadcast_ether_addr(target_addr) &&
 602                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 603                 rcu_read_lock();
 604                 mpath = mesh_path_lookup(sdata, orig_addr);
 605                 if (mpath) {
 606                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 607                                 reply = true;
 608                                 target_addr = sdata->vif.addr;
 609                                 target_sn = ++ifmsh->sn;
 610                                 target_metric = 0;
 611                                 ifmsh->last_sn_update = jiffies;
 612                         }
 613                         if (root_is_gate)
 614                                 mesh_path_add_gate(mpath);
 615                 }
 616                 rcu_read_unlock();
 617         } else {
 618                 rcu_read_lock();
 619                 mpath = mesh_path_lookup(sdata, target_addr);
 620                 if (mpath) {
 621                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 622                                         SN_LT(mpath->sn, target_sn)) {
 623                                 mpath->sn = target_sn;
 624                                 mpath->flags |= MESH_PATH_SN_VALID;
 625                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 626                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 627                                 reply = true;
 628                                 target_metric = mpath->metric;
 629                                 target_sn = mpath->sn;
 630                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 631                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 632                         }
 633                 }
 634                 rcu_read_unlock();
 635         }
 636
 637         if (reply) {
 638                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 639                 ttl = ifmsh->mshcfg.element_ttl;
 640                 if (ttl != 0) {
 641                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 642                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 643                                                orig_sn, 0, target_addr,
 644                                                target_sn, mgmt->sa, 0, ttl,
 645                                                lifetime, target_metric, 0,
 646                                                sdata);
 647                 } else {
 648                         ifmsh->mshstats.dropped_frames_ttl++;
 649                 }
 650         }
 651
 652         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 653                 u32 preq_id;
 654                 u8 hopcount;
 655
 656                 ttl = PREQ_IE_TTL(preq_elem);
 657                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 658                 if (ttl <= 1) {
 659                         ifmsh->mshstats.dropped_frames_ttl++;
 660                         return;
 661                 }
 662                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 663                 --ttl;
 664                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 665                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 666                 da = (mpath && mpath->is_root) ?
 667                         mpath->rann_snd_addr : broadcast_addr;
 668
 669                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 670                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 671                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 672                 }
 673
 674                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 675                                        orig_sn, target_flags, target_addr,
 676                                        target_sn, da, hopcount, ttl, lifetime,
 677                                        orig_metric, preq_id, sdata);
 678                 if (!is_multicast_ether_addr(da))
 679                         ifmsh->mshstats.fwded_unicast++;
 680                 else
 681                         ifmsh->mshstats.fwded_mcast++;
 682                 ifmsh->mshstats.fwded_frames++;
 683         }
 684 }
 685
 686
 687 static inline struct sta_info *
 688 next_hop_deref_protected(struct mesh_path *mpath)
 689 {
 690         return rcu_dereference_protected(mpath->next_hop,
 691                                          lockdep_is_held(&mpath->state_lock));
 692 }
 693
 694
 695 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 696                                     struct ieee80211_mgmt *mgmt,
 697                                     const u8 *prep_elem, u32 metric)
 698 {
 699         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 700         struct mesh_path *mpath;
 701         const u8 *target_addr, *orig_addr;
 702         u8 ttl, hopcount, flags;
 703         u8 next_hop[ETH_ALEN];
 704         u32 target_sn, orig_sn, lifetime;
 705
 706         mhwmp_dbg(sdata, "received PREP from %pM\n",
 707                   PREP_IE_TARGET_ADDR(prep_elem));
 708
 709         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 710         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 711                 /* destination, no forwarding required */
 712                 return;
 713
 714         if (!ifmsh->mshcfg.dot11MeshForwarding)
 715                 return;
 716
 717         ttl = PREP_IE_TTL(prep_elem);
 718         if (ttl <= 1) {
 719                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 720                 return;
 721         }
 722
 723         rcu_read_lock();
 724         mpath = mesh_path_lookup(sdata, orig_addr);
 725         if (mpath)
 726                 spin_lock_bh(&mpath->state_lock);
 727         else
 728                 goto fail;
 729         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 730                 spin_unlock_bh(&mpath->state_lock);
 731                 goto fail;
 732         }
 733         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 734         spin_unlock_bh(&mpath->state_lock);
 735         --ttl;
 736         flags = PREP_IE_FLAGS(prep_elem);
 737         lifetime = PREP_IE_LIFETIME(prep_elem);
 738         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 739         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 740         target_sn = PREP_IE_TARGET_SN(prep_elem);
 741         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 742
 743         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 744                                target_addr, target_sn, next_hop, hopcount,
 745                                ttl, lifetime, metric, 0, sdata);
 746         rcu_read_unlock();
 747
 748         sdata->u.mesh.mshstats.fwded_unicast++;
 749         sdata->u.mesh.mshstats.fwded_frames++;
 750         return;
 751
 752 fail:
 753         rcu_read_unlock();
 754         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 755 }
 756
 757 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 758                                     struct ieee80211_mgmt *mgmt,
 759                                     const u8 *perr_elem)
 760 {
 761         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 762         struct mesh_path *mpath;
 763         u8 ttl;
 764         const u8 *ta, *target_addr;
 765         u32 target_sn;
 766         u16 target_rcode;
 767
 768         ta = mgmt->sa;
 769         ttl = PERR_IE_TTL(perr_elem);
 770         if (ttl <= 1) {
 771                 ifmsh->mshstats.dropped_frames_ttl++;
 772                 return;
 773         }
 774         ttl--;
 775         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 776         target_sn = PERR_IE_TARGET_SN(perr_elem);
 777         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 778
 779         rcu_read_lock();
 780         mpath = mesh_path_lookup(sdata, target_addr);
 781         if (mpath) {
 782                 struct sta_info *sta;
 783
 784                 spin_lock_bh(&mpath->state_lock);
 785                 sta = next_hop_deref_protected(mpath);
 786                 if (mpath->flags & MESH_PATH_ACTIVE &&
 787                     ether_addr_equal(ta, sta->sta.addr) &&
 788                     !(mpath->flags & MESH_PATH_FIXED) &&
 789                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 790                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 791                         mpath->flags &= ~MESH_PATH_ACTIVE;
 792                         if (target_sn != 0)
 793                                 mpath->sn = target_sn;
 794                         else
 795                                 mpath->sn += 1;
 796                         spin_unlock_bh(&mpath->state_lock);
 797                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 798                                 goto endperr;
 799                         mesh_path_error_tx(sdata, ttl, target_addr,
 800                                            target_sn, target_rcode,
 801                                            broadcast_addr);
 802                 } else
 803                         spin_unlock_bh(&mpath->state_lock);
 804         }
 805 endperr:
 806         rcu_read_unlock();
 807 }
 808
 809 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 810                                     struct ieee80211_mgmt *mgmt,
 811                                     const struct ieee80211_rann_ie *rann)
 812 {
 813         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 814         struct ieee80211_local *local = sdata->local;
 815         struct sta_info *sta;
 816         struct mesh_path *mpath;
 817         u8 ttl, flags, hopcount;
 818         const u8 *orig_addr;
 819         u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
 820         bool root_is_gate;
 821
 822         ttl = rann->rann_ttl;
 823         flags = rann->rann_flags;
 824         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 825         orig_addr = rann->rann_addr;
 826         orig_sn = le32_to_cpu(rann->rann_seq);
 827         interval = le32_to_cpu(rann->rann_interval);
 828         hopcount = rann->rann_hopcount;
 829         hopcount++;
 830         orig_metric = le32_to_cpu(rann->rann_metric);
 831
 832         /*  Ignore our own RANNs */
 833         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 834                 return;
 835
 836         mhwmp_dbg(sdata,
 837                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 838                   orig_addr, mgmt->sa, root_is_gate);
 839
 840         rcu_read_lock();
 841         sta = sta_info_get(sdata, mgmt->sa);
 842         if (!sta) {
 843                 rcu_read_unlock();
 844                 return;
 845         }
 846
 847         last_hop_metric = airtime_link_metric_get(local, sta);
 848         new_metric = orig_metric + last_hop_metric;
 849         if (new_metric < orig_metric)
 850                 new_metric = MAX_METRIC;
 851
 852         mpath = mesh_path_lookup(sdata, orig_addr);
 853         if (!mpath) {
 854                 mpath = mesh_path_add(sdata, orig_addr);
 855                 if (IS_ERR(mpath)) {
 856                         rcu_read_unlock();
 857                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 858                         return;
 859                 }
 860         }
 861
 862         if (!(SN_LT(mpath->sn, orig_sn)) &&
 863             !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
 864                 rcu_read_unlock();
 865                 return;
 866         }
 867
 868         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 869              (time_after(jiffies, mpath->last_preq_to_root +
 870                                   root_path_confirmation_jiffies(sdata)) ||
 871              time_before(jiffies, mpath->last_preq_to_root))) &&
 872              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 873                 mhwmp_dbg(sdata,
 874                           "time to refresh root mpath %pM\n",
 875                           orig_addr);
 876                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 877                 mpath->last_preq_to_root = jiffies;
 878         }
 879
 880         mpath->sn = orig_sn;
 881         mpath->rann_metric = new_metric;
 882         mpath->is_root = true;
 883         /* Recording RANNs sender address to send individually
 884          * addressed PREQs destined for root mesh STA */
 885         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 886
 887         if (root_is_gate)
 888                 mesh_path_add_gate(mpath);
 889
 890         if (ttl <= 1) {
 891                 ifmsh->mshstats.dropped_frames_ttl++;
 892                 rcu_read_unlock();
 893                 return;
 894         }
 895         ttl--;
 896
 897         if (ifmsh->mshcfg.dot11MeshForwarding) {
 898                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 899                                        orig_sn, 0, NULL, 0, broadcast_addr,
 900                                        hopcount, ttl, interval,
 901                                        new_metric, 0, sdata);
 902         }
 903
 904         rcu_read_unlock();
 905 }
 906
 907
 908 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 909                             struct ieee80211_mgmt *mgmt, size_t len)
 910 {
 911         struct ieee802_11_elems elems;
 912         size_t baselen;
 913         u32 path_metric;
 914         struct sta_info *sta;
 915
 916         /* need action_code */
 917         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 918                 return;
 919
 920         rcu_read_lock();
 921         sta = sta_info_get(sdata, mgmt->sa);
 922         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 923                 rcu_read_unlock();
 924                 return;
 925         }
 926         rcu_read_unlock();
 927
 928         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 929         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 930                                len - baselen, false, &elems, mgmt->bssid, NULL);
 931
 932         if (elems.preq) {
 933                 if (elems.preq_len != 37)
 934                         /* Right now we support just 1 destination and no AE */
 935                         return;
 936                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 937                                                   MPATH_PREQ);
 938                 if (path_metric)
 939                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 940                                                 path_metric);
 941         }
 942         if (elems.prep) {
 943                 if (elems.prep_len != 31)
 944                         /* Right now we support no AE */
 945                         return;
 946                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 947                                                   MPATH_PREP);
 948                 if (path_metric)
 949                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 950                                                 path_metric);
 951         }
 952         if (elems.perr) {
 953                 if (elems.perr_len != 15)
 954                         /* Right now we support only one destination per PERR */
 955                         return;
 956                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 957         }
 958         if (elems.rann)
 959                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 960 }
 961
 962 /**
 963  * mesh_queue_preq - queue a PREQ to a given destination
 964  *
 965  * @mpath: mesh path to discover
 966  * @flags: special attributes of the PREQ to be sent
 967  *
 968  * Locking: the function must be called from within a rcu read lock block.
 969  *
 970  */
 971 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 972 {
 973         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 974         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 975         struct mesh_preq_queue *preq_node;
 976
 977         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 978         if (!preq_node) {
 979                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 980                 return;
 981         }
 982
 983         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 984         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 985                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 986                 kfree(preq_node);
 987                 if (printk_ratelimit())
 988                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 989                 return;
 990         }
 991
 992         spin_lock(&mpath->state_lock);
 993         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 994                 spin_unlock(&mpath->state_lock);
 995                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 996                 kfree(preq_node);
 997                 return;
 998         }
 999
1000         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
1001         preq_node->flags = flags;
1002
1003         mpath->flags |= MESH_PATH_REQ_QUEUED;
1004         spin_unlock(&mpath->state_lock);
1005
1006         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
1007         ++ifmsh->preq_queue_len;
1008         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1009
1010         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
1011                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1012
1013         else if (time_before(jiffies, ifmsh->last_preq)) {
1014                 /* avoid long wait if did not send preqs for a long time
1015                  * and jiffies wrapped around
1016                  */
1017                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1018                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1019         } else
1020                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1021                                                 min_preq_int_jiff(sdata));
1022 }
1023
1024 /**
1025  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1026  *
1027  * @sdata: local mesh subif
1028  */
1029 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1030 {
1031         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1032         struct mesh_preq_queue *preq_node;
1033         struct mesh_path *mpath;
1034         u8 ttl, target_flags = 0;
1035         const u8 *da;
1036         u32 lifetime;
1037
1038         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1039         if (!ifmsh->preq_queue_len ||
1040                 time_before(jiffies, ifmsh->last_preq +
1041                                 min_preq_int_jiff(sdata))) {
1042                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1043                 return;
1044         }
1045
1046         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1047                         struct mesh_preq_queue, list);
1048         list_del(&preq_node->list);
1049         --ifmsh->preq_queue_len;
1050         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1051
1052         rcu_read_lock();
1053         mpath = mesh_path_lookup(sdata, preq_node->dst);
1054         if (!mpath)
1055                 goto enddiscovery;
1056
1057         spin_lock_bh(&mpath->state_lock);
1058         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1059                 spin_unlock_bh(&mpath->state_lock);
1060                 goto enddiscovery;
1061         }
1062         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1063         if (preq_node->flags & PREQ_Q_F_START) {
1064                 if (mpath->flags & MESH_PATH_RESOLVING) {
1065                         spin_unlock_bh(&mpath->state_lock);
1066                         goto enddiscovery;
1067                 } else {
1068                         mpath->flags &= ~MESH_PATH_RESOLVED;
1069                         mpath->flags |= MESH_PATH_RESOLVING;
1070                         mpath->discovery_retries = 0;
1071                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1072                 }
1073         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1074                         mpath->flags & MESH_PATH_RESOLVED) {
1075                 mpath->flags &= ~MESH_PATH_RESOLVING;
1076                 spin_unlock_bh(&mpath->state_lock);
1077                 goto enddiscovery;
1078         }
1079
1080         ifmsh->last_preq = jiffies;
1081
1082         if (time_after(jiffies, ifmsh->last_sn_update +
1083                                 net_traversal_jiffies(sdata)) ||
1084             time_before(jiffies, ifmsh->last_sn_update)) {
1085                 ++ifmsh->sn;
1086                 sdata->u.mesh.last_sn_update = jiffies;
1087         }
1088         lifetime = default_lifetime(sdata);
1089         ttl = sdata->u.mesh.mshcfg.element_ttl;
1090         if (ttl == 0) {
1091                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1092                 spin_unlock_bh(&mpath->state_lock);
1093                 goto enddiscovery;
1094         }
1095
1096         if (preq_node->flags & PREQ_Q_F_REFRESH)
1097                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1098         else
1099                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1100
1101         spin_unlock_bh(&mpath->state_lock);
1102         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1103         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1104                                target_flags, mpath->dst, mpath->sn, da, 0,
1105                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1106
1107         spin_lock_bh(&mpath->state_lock);
1108         if (!(mpath->flags & MESH_PATH_DELETED))
1109                 mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1110         spin_unlock_bh(&mpath->state_lock);
1111
1112 enddiscovery:
1113         rcu_read_unlock();
1114         kfree(preq_node);
1115 }
1116
1117 /**
1118  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1119  *
1120  * @skb: 802.11 frame to be sent
1121  * @sdata: network subif the frame will be sent through
1122  *
1123  * Lookup next hop for given skb and start path discovery if no
1124  * forwarding information is found.
1125  *
1126  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1127  * skb is freed here if no mpath could be allocated.
1128  */
1129 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1130                          struct sk_buff *skb)
1131 {
1132         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1133         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1134         struct mesh_path *mpath;
1135         struct sk_buff *skb_to_free = NULL;
1136         u8 *target_addr = hdr->addr3;
1137
1138         /* Nulls are only sent to peers for PS and should be pre-addressed */
1139         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1140                 return 0;
1141
1142         /* Allow injected packets to bypass mesh routing */
1143         if (info->control.flags & IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP)
1144                 return 0;
1145
1146         if (!mesh_nexthop_lookup(sdata, skb))
1147                 return 0;
1148
1149         /* no nexthop found, start resolving */
1150         mpath = mesh_path_lookup(sdata, target_addr);
1151         if (!mpath) {
1152                 mpath = mesh_path_add(sdata, target_addr);
1153                 if (IS_ERR(mpath)) {
1154                         mesh_path_discard_frame(sdata, skb);
1155                         return PTR_ERR(mpath);
1156                 }
1157         }
1158
1159         if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1160             mesh_path_sel_is_hwmp(sdata))
1161                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1162
1163         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1164                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1165
1166         info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
1167         ieee80211_set_qos_hdr(sdata, skb);
1168         skb_queue_tail(&mpath->frame_queue, skb);
1169         if (skb_to_free)
1170                 mesh_path_discard_frame(sdata, skb_to_free);
1171
1172         return -ENOENT;
1173 }
1174
1175 /**
1176  * mesh_nexthop_lookup_nolearn - try to set next hop without path discovery
1177  * @skb: 802.11 frame to be sent
1178  * @sdata: network subif the frame will be sent through
1179  *
1180  * Check if the meshDA (addr3) of a unicast frame is a direct neighbor.
1181  * And if so, set the RA (addr1) to it to transmit to this node directly,
1182  * avoiding PREQ/PREP path discovery.
1183  *
1184  * Returns: 0 if the next hop was found and -ENOENT otherwise.
1185  */
1186 static int mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data *sdata,
1187                                        struct sk_buff *skb)
1188 {
1189         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1190         struct sta_info *sta;
1191
1192         if (is_multicast_ether_addr(hdr->addr1))
1193                 return -ENOENT;
1194
1195         rcu_read_lock();
1196         sta = sta_info_get(sdata, hdr->addr3);
1197
1198         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
1199                 rcu_read_unlock();
1200                 return -ENOENT;
1201         }
1202         rcu_read_unlock();
1203
1204         memcpy(hdr->addr1, hdr->addr3, ETH_ALEN);
1205         memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1206         return 0;
1207 }
1208
1209 /**
1210  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1211  * this function is considered "using" the associated mpath, so preempt a path
1212  * refresh if this mpath expires soon.
1213  *
1214  * @skb: 802.11 frame to be sent
1215  * @sdata: network subif the frame will be sent through
1216  *
1217  * Returns: 0 if the next hop was found. Nonzero otherwise.
1218  */
1219 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1220                         struct sk_buff *skb)
1221 {
1222         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1223         struct mesh_path *mpath;
1224         struct sta_info *next_hop;
1225         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1226         u8 *target_addr = hdr->addr3;
1227
1228         if (ifmsh->mshcfg.dot11MeshNolearn &&
1229             !mesh_nexthop_lookup_nolearn(sdata, skb))
1230                 return 0;
1231
1232         mpath = mesh_path_lookup(sdata, target_addr);
1233         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1234                 return -ENOENT;
1235
1236         if (time_after(jiffies,
1237                        mpath->exp_time -
1238                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1239             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1240             !(mpath->flags & MESH_PATH_RESOLVING) &&
1241             !(mpath->flags & MESH_PATH_FIXED))
1242                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1243
1244         next_hop = rcu_dereference(mpath->next_hop);
1245         if (next_hop) {
1246                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1247                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1248                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1249                 return 0;
1250         }
1251
1252         return -ENOENT;
1253 }
1254
1255 void mesh_path_timer(struct timer_list *t)
1256 {
1257         struct mesh_path *mpath = from_timer(mpath, t, timer);
1258         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1259         int ret;
1260
1261         if (sdata->local->quiescing)
1262                 return;
1263
1264         spin_lock_bh(&mpath->state_lock);
1265         if (mpath->flags & MESH_PATH_RESOLVED ||
1266                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1267                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1268                 spin_unlock_bh(&mpath->state_lock);
1269         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1270                 ++mpath->discovery_retries;
1271                 mpath->discovery_timeout *= 2;
1272                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1273                 spin_unlock_bh(&mpath->state_lock);
1274                 mesh_queue_preq(mpath, 0);
1275         } else {
1276                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1277                                   MESH_PATH_RESOLVED |
1278                                   MESH_PATH_REQ_QUEUED);
1279                 mpath->exp_time = jiffies;
1280                 spin_unlock_bh(&mpath->state_lock);
1281                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1282                         ret = mesh_path_send_to_gates(mpath);
1283                         if (ret)
1284                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1285                 } else
1286                         mesh_path_flush_pending(mpath);
1287         }
1288 }
1289
1290 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1291 {
1292         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1293         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1294         u8 flags, target_flags = 0;
1295
1296         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1297                         ? RANN_FLAG_IS_GATE : 0;
1298
1299         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1300         case IEEE80211_PROACTIVE_RANN:
1301                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1302                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1303                                        0, ifmsh->mshcfg.element_ttl,
1304                                        interval, 0, 0, sdata);
1305                 break;
1306         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1307                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1308                 fallthrough;
1309         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1310                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1311                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1312                                 IEEE80211_PREQ_USN_FLAG;
1313                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1314                                        ++ifmsh->sn, target_flags,
1315                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1316                                        0, ifmsh->mshcfg.element_ttl, interval,
1317                                        0, ifmsh->preq_id++, sdata);
1318                 break;
1319         default:
1320                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1321                 return;
1322         }
1323 }