net/mac80211/mesh_hwmp.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/etherdevice.h>
  12 #include <asm/unaligned.h>
  13 #include "wme.h"
  14 #include "mesh.h"
  15
  16 #define TEST_FRAME_LEN  8192
  17 #define MAX_METRIC      0xffffffff
  18 #define ARITH_SHIFT     8
  19 #define LINK_FAIL_THRESH 95
  20
  21 #define MAX_PREQ_QUEUE_LEN      64
  22
  23 static void mesh_queue_preq(struct mesh_path *, u8);
  24
  25 static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
  26 {
  27         if (ae)
  28                 offset += 6;
  29         return get_unaligned_le32(preq_elem + offset);
  30 }
  31
  32 static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
  33 {
  34         if (ae)
  35                 offset += 6;
  36         return get_unaligned_le16(preq_elem + offset);
  37 }
  38
  39 /* HWMP IE processing macros */
  40 #define AE_F                    (1<<6)
  41 #define AE_F_SET(x)             (*x & AE_F)
  42 #define PREQ_IE_FLAGS(x)        (*(x))
  43 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  44 #define PREQ_IE_TTL(x)          (*(x + 2))
  45 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  46 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  47 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  48 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  49 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  50 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  51 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  52 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  53
  54
  55 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  56 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  57 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  58 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  59 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  60 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  61 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  62 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  63 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  64
  65 #define PERR_IE_TTL(x)          (*(x))
  66 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  67 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  68 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  69 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  70
  71 #define MSEC_TO_TU(x) (x*1000/1024)
  72 #define SN_GT(x, y) ((s32)(y - x) < 0)
  73 #define SN_LT(x, y) ((s32)(x - y) < 0)
  74 #define MAX_SANE_SN_DELTA 32
  75
  76 static inline u32 SN_DELTA(u32 x, u32 y)
  77 {
  78         return x >= y ? x - y : y - x;
  79 }
  80
  81 #define net_traversal_jiffies(s) \
  82         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  83 #define default_lifetime(s) \
  84         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  85 #define min_preq_int_jiff(s) \
  86         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  87 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  88 #define disc_timeout_jiff(s) \
  89         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  90 #define root_path_confirmation_jiffies(s) \
  91         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  92
  93 enum mpath_frame_type {
  94         MPATH_PREQ = 0,
  95         MPATH_PREP,
  96         MPATH_PERR,
  97         MPATH_RANN
  98 };
  99
 100 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 101
 102 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 103                                   const u8 *orig_addr, u32 orig_sn,
 104                                   u8 target_flags, const u8 *target,
 105                                   u32 target_sn, const u8 *da,
 106                                   u8 hop_count, u8 ttl,
 107                                   u32 lifetime, u32 metric, u32 preq_id,
 108                                   struct ieee80211_sub_if_data *sdata)
 109 {
 110         struct ieee80211_local *local = sdata->local;
 111         struct sk_buff *skb;
 112         struct ieee80211_mgmt *mgmt;
 113         u8 *pos, ie_len;
 114         int hdr_len = offsetofend(struct ieee80211_mgmt,
 115                                   u.action.u.mesh_action);
 116
 117         skb = dev_alloc_skb(local->tx_headroom +
 118                             hdr_len +
 119                             2 + 37); /* max HWMP IE */
 120         if (!skb)
 121                 return -1;
 122         skb_reserve(skb, local->tx_headroom);
 123         mgmt = skb_put_zero(skb, hdr_len);
 124         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 125                                           IEEE80211_STYPE_ACTION);
 126
 127         memcpy(mgmt->da, da, ETH_ALEN);
 128         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 129         /* BSSID == SA */
 130         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 131         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 132         mgmt->u.action.u.mesh_action.action_code =
 133                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 134
 135         switch (action) {
 136         case MPATH_PREQ:
 137                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 138                 ie_len = 37;
 139                 pos = skb_put(skb, 2 + ie_len);
 140                 *pos++ = WLAN_EID_PREQ;
 141                 break;
 142         case MPATH_PREP:
 143                 mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
 144                 ie_len = 31;
 145                 pos = skb_put(skb, 2 + ie_len);
 146                 *pos++ = WLAN_EID_PREP;
 147                 break;
 148         case MPATH_RANN:
 149                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 150                 ie_len = sizeof(struct ieee80211_rann_ie);
 151                 pos = skb_put(skb, 2 + ie_len);
 152                 *pos++ = WLAN_EID_RANN;
 153                 break;
 154         default:
 155                 kfree_skb(skb);
 156                 return -ENOTSUPP;
 157         }
 158         *pos++ = ie_len;
 159         *pos++ = flags;
 160         *pos++ = hop_count;
 161         *pos++ = ttl;
 162         if (action == MPATH_PREP) {
 163                 memcpy(pos, target, ETH_ALEN);
 164                 pos += ETH_ALEN;
 165                 put_unaligned_le32(target_sn, pos);
 166                 pos += 4;
 167         } else {
 168                 if (action == MPATH_PREQ) {
 169                         put_unaligned_le32(preq_id, pos);
 170                         pos += 4;
 171                 }
 172                 memcpy(pos, orig_addr, ETH_ALEN);
 173                 pos += ETH_ALEN;
 174                 put_unaligned_le32(orig_sn, pos);
 175                 pos += 4;
 176         }
 177         put_unaligned_le32(lifetime, pos); /* interval for RANN */
 178         pos += 4;
 179         put_unaligned_le32(metric, pos);
 180         pos += 4;
 181         if (action == MPATH_PREQ) {
 182                 *pos++ = 1; /* destination count */
 183                 *pos++ = target_flags;
 184                 memcpy(pos, target, ETH_ALEN);
 185                 pos += ETH_ALEN;
 186                 put_unaligned_le32(target_sn, pos);
 187                 pos += 4;
 188         } else if (action == MPATH_PREP) {
 189                 memcpy(pos, orig_addr, ETH_ALEN);
 190                 pos += ETH_ALEN;
 191                 put_unaligned_le32(orig_sn, pos);
 192                 pos += 4;
 193         }
 194
 195         ieee80211_tx_skb(sdata, skb);
 196         return 0;
 197 }
 198
 199
 200 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 201  *  headroom in case the frame is encrypted. */
 202 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 203                 struct sk_buff *skb)
 204 {
 205         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 206         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 207
 208         skb_reset_mac_header(skb);
 209         skb_reset_network_header(skb);
 210         skb_reset_transport_header(skb);
 211
 212         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 213         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 214         skb->priority = 7;
 215
 216         info->control.vif = &sdata->vif;
 217         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 218         ieee80211_set_qos_hdr(sdata, skb);
 219         ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
 220 }
 221
 222 /**
 223  * mesh_path_error_tx - Sends a PERR mesh management frame
 224  *
 225  * @ttl: allowed remaining hops
 226  * @target: broken destination
 227  * @target_sn: SN of the broken destination
 228  * @target_rcode: reason code for this PERR
 229  * @ra: node this frame is addressed to
 230  * @sdata: local mesh subif
 231  *
 232  * Note: This function may be called with driver locks taken that the driver
 233  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 234  * frame directly but add it to the pending queue instead.
 235  */
 236 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 237                        u8 ttl, const u8 *target, u32 target_sn,
 238                        u16 target_rcode, const u8 *ra)
 239 {
 240         struct ieee80211_local *local = sdata->local;
 241         struct sk_buff *skb;
 242         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 243         struct ieee80211_mgmt *mgmt;
 244         u8 *pos, ie_len;
 245         int hdr_len = offsetofend(struct ieee80211_mgmt,
 246                                   u.action.u.mesh_action);
 247
 248         if (time_before(jiffies, ifmsh->next_perr))
 249                 return -EAGAIN;
 250
 251         skb = dev_alloc_skb(local->tx_headroom +
 252                             sdata->encrypt_headroom +
 253                             IEEE80211_ENCRYPT_TAILROOM +
 254                             hdr_len +
 255                             2 + 15 /* PERR IE */);
 256         if (!skb)
 257                 return -1;
 258         skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom);
 259         mgmt = skb_put_zero(skb, hdr_len);
 260         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 261                                           IEEE80211_STYPE_ACTION);
 262
 263         memcpy(mgmt->da, ra, ETH_ALEN);
 264         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 265         /* BSSID == SA */
 266         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 267         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 268         mgmt->u.action.u.mesh_action.action_code =
 269                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 270         ie_len = 15;
 271         pos = skb_put(skb, 2 + ie_len);
 272         *pos++ = WLAN_EID_PERR;
 273         *pos++ = ie_len;
 274         /* ttl */
 275         *pos++ = ttl;
 276         /* number of destinations */
 277         *pos++ = 1;
 278         /* Flags field has AE bit only as defined in
 279          * sec 8.4.2.117 IEEE802.11-2012
 280          */
 281         *pos = 0;
 282         pos++;
 283         memcpy(pos, target, ETH_ALEN);
 284         pos += ETH_ALEN;
 285         put_unaligned_le32(target_sn, pos);
 286         pos += 4;
 287         put_unaligned_le16(target_rcode, pos);
 288
 289         /* see note in function header */
 290         prepare_frame_for_deferred_tx(sdata, skb);
 291         ifmsh->next_perr = TU_TO_EXP_TIME(
 292                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 293         ieee80211_add_pending_skb(local, skb);
 294         return 0;
 295 }
 296
 297 void ieee80211s_update_metric(struct ieee80211_local *local,
 298                               struct sta_info *sta,
 299                               struct ieee80211_tx_status *st)
 300 {
 301         struct ieee80211_tx_info *txinfo = st->info;
 302         int failed;
 303
 304         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 305
 306         /* moving average, scaled to 100.
 307          * feed failure as 100 and success as 0
 308          */
 309         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
 310         if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
 311                         LINK_FAIL_THRESH)
 312                 mesh_plink_broken(sta);
 313 }
 314
 315 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 316                                    struct sta_info *sta)
 317 {
 318         struct rate_info rinfo;
 319         /* This should be adjusted for each device */
 320         int device_constant = 1 << ARITH_SHIFT;
 321         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 322         int s_unit = 1 << ARITH_SHIFT;
 323         int rate, err;
 324         u32 tx_time, estimated_retx;
 325         u64 result;
 326         unsigned long fail_avg =
 327                 ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
 328
 329         /* Try to get rate based on HW/SW RC algorithm.
 330          * Rate is returned in units of Kbps, correct this
 331          * to comply with airtime calculation units
 332          * Round up in case we get rate < 100Kbps
 333          */
 334         rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
 335
 336         if (rate) {
 337                 err = 0;
 338         } else {
 339                 if (fail_avg > LINK_FAIL_THRESH)
 340                         return MAX_METRIC;
 341
 342                 sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
 343                 rate = cfg80211_calculate_bitrate(&rinfo);
 344                 if (WARN_ON(!rate))
 345                         return MAX_METRIC;
 346
 347                 err = (fail_avg << ARITH_SHIFT) / 100;
 348         }
 349
 350         /* bitrate is in units of 100 Kbps, while we need rate in units of
 351          * 1Mbps. This will be corrected on tx_time computation.
 352          */
 353         tx_time = (device_constant + 10 * test_frame_len / rate);
 354         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 355         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
 356         return (u32)result;
 357 }
 358
 359 /**
 360  * hwmp_route_info_get - Update routing info to originator and transmitter
 361  *
 362  * @sdata: local mesh subif
 363  * @mgmt: mesh management frame
 364  * @hwmp_ie: hwmp information element (PREP or PREQ)
 365  * @action: type of hwmp ie
 366  *
 367  * This function updates the path routing information to the originator and the
 368  * transmitter of a HWMP PREQ or PREP frame.
 369  *
 370  * Returns: metric to frame originator or 0 if the frame should not be further
 371  * processed
 372  *
 373  * Notes: this function is the only place (besides user-provided info) where
 374  * path routing information is updated.
 375  */
 376 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 377                                struct ieee80211_mgmt *mgmt,
 378                                const u8 *hwmp_ie, enum mpath_frame_type action)
 379 {
 380         struct ieee80211_local *local = sdata->local;
 381         struct mesh_path *mpath;
 382         struct sta_info *sta;
 383         bool fresh_info;
 384         const u8 *orig_addr, *ta;
 385         u32 orig_sn, orig_metric;
 386         unsigned long orig_lifetime, exp_time;
 387         u32 last_hop_metric, new_metric;
 388         bool process = true;
 389
 390         rcu_read_lock();
 391         sta = sta_info_get(sdata, mgmt->sa);
 392         if (!sta) {
 393                 rcu_read_unlock();
 394                 return 0;
 395         }
 396
 397         last_hop_metric = airtime_link_metric_get(local, sta);
 398         /* Update and check originator routing info */
 399         fresh_info = true;
 400
 401         switch (action) {
 402         case MPATH_PREQ:
 403                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 404                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 405                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 406                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 407                 break;
 408         case MPATH_PREP:
 409                 /* Originator here refers to the MP that was the target in the
 410                  * Path Request. We divert from the nomenclature in the draft
 411                  * so that we can easily use a single function to gather path
 412                  * information from both PREQ and PREP frames.
 413                  */
 414                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 415                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 416                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 417                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 418                 break;
 419         default:
 420                 rcu_read_unlock();
 421                 return 0;
 422         }
 423         new_metric = orig_metric + last_hop_metric;
 424         if (new_metric < orig_metric)
 425                 new_metric = MAX_METRIC;
 426         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 427
 428         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 429                 /* This MP is the originator, we are not interested in this
 430                  * frame, except for updating transmitter's path info.
 431                  */
 432                 process = false;
 433                 fresh_info = false;
 434         } else {
 435                 mpath = mesh_path_lookup(sdata, orig_addr);
 436                 if (mpath) {
 437                         spin_lock_bh(&mpath->state_lock);
 438                         if (mpath->flags & MESH_PATH_FIXED)
 439                                 fresh_info = false;
 440                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 441                             (mpath->flags & MESH_PATH_SN_VALID)) {
 442                                 if (SN_GT(mpath->sn, orig_sn) ||
 443                                     (mpath->sn == orig_sn &&
 444                                      new_metric >= mpath->metric)) {
 445                                         process = false;
 446                                         fresh_info = false;
 447                                 }
 448                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 449                                 bool have_sn, newer_sn, bounced;
 450
 451                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 452                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 453                                 bounced = have_sn &&
 454                                           (SN_DELTA(orig_sn, mpath->sn) >
 455                                                         MAX_SANE_SN_DELTA);
 456
 457                                 if (!have_sn || newer_sn) {
 458                                         /* if SN is newer than what we had
 459                                          * then we can take it */;
 460                                 } else if (bounced) {
 461                                         /* if SN is way different than what
 462                                          * we had then assume the other side
 463                                          * rebooted or restarted */;
 464                                 } else {
 465                                         process = false;
 466                                         fresh_info = false;
 467                                 }
 468                         }
 469                 } else {
 470                         mpath = mesh_path_add(sdata, orig_addr);
 471                         if (IS_ERR(mpath)) {
 472                                 rcu_read_unlock();
 473                                 return 0;
 474                         }
 475                         spin_lock_bh(&mpath->state_lock);
 476                 }
 477
 478                 if (fresh_info) {
 479                         mesh_path_assign_nexthop(mpath, sta);
 480                         mpath->flags |= MESH_PATH_SN_VALID;
 481                         mpath->metric = new_metric;
 482                         mpath->sn = orig_sn;
 483                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 484                                           ?  mpath->exp_time : exp_time;
 485                         mesh_path_activate(mpath);
 486                         spin_unlock_bh(&mpath->state_lock);
 487                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 488                         /* init it at a low value - 0 start is tricky */
 489                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 490                         mesh_path_tx_pending(mpath);
 491                         /* draft says preq_id should be saved to, but there does
 492                          * not seem to be any use for it, skipping by now
 493                          */
 494                 } else
 495                         spin_unlock_bh(&mpath->state_lock);
 496         }
 497
 498         /* Update and check transmitter routing info */
 499         ta = mgmt->sa;
 500         if (ether_addr_equal(orig_addr, ta))
 501                 fresh_info = false;
 502         else {
 503                 fresh_info = true;
 504
 505                 mpath = mesh_path_lookup(sdata, ta);
 506                 if (mpath) {
 507                         spin_lock_bh(&mpath->state_lock);
 508                         if ((mpath->flags & MESH_PATH_FIXED) ||
 509                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 510                                         (last_hop_metric > mpath->metric)))
 511                                 fresh_info = false;
 512                 } else {
 513                         mpath = mesh_path_add(sdata, ta);
 514                         if (IS_ERR(mpath)) {
 515                                 rcu_read_unlock();
 516                                 return 0;
 517                         }
 518                         spin_lock_bh(&mpath->state_lock);
 519                 }
 520
 521                 if (fresh_info) {
 522                         mesh_path_assign_nexthop(mpath, sta);
 523                         mpath->metric = last_hop_metric;
 524                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 525                                           ?  mpath->exp_time : exp_time;
 526                         mesh_path_activate(mpath);
 527                         spin_unlock_bh(&mpath->state_lock);
 528                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 529                         /* init it at a low value - 0 start is tricky */
 530                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 531                         mesh_path_tx_pending(mpath);
 532                 } else
 533                         spin_unlock_bh(&mpath->state_lock);
 534         }
 535
 536         rcu_read_unlock();
 537
 538         return process ? new_metric : 0;
 539 }
 540
 541 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 542                                     struct ieee80211_mgmt *mgmt,
 543                                     const u8 *preq_elem, u32 orig_metric)
 544 {
 545         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 546         struct mesh_path *mpath = NULL;
 547         const u8 *target_addr, *orig_addr;
 548         const u8 *da;
 549         u8 target_flags, ttl, flags;
 550         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 551         bool reply = false;
 552         bool forward = true;
 553         bool root_is_gate;
 554
 555         /* Update target SN, if present */
 556         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 557         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 558         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 559         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 560         target_flags = PREQ_IE_TARGET_F(preq_elem);
 561         /* Proactive PREQ gate announcements */
 562         flags = PREQ_IE_FLAGS(preq_elem);
 563         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 564
 565         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 566
 567         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 568                 mhwmp_dbg(sdata, "PREQ is for us\n");
 569                 forward = false;
 570                 reply = true;
 571                 target_metric = 0;
 572
 573                 if (SN_GT(target_sn, ifmsh->sn))
 574                         ifmsh->sn = target_sn;
 575
 576                 if (time_after(jiffies, ifmsh->last_sn_update +
 577                                         net_traversal_jiffies(sdata)) ||
 578                     time_before(jiffies, ifmsh->last_sn_update)) {
 579                         ++ifmsh->sn;
 580                         ifmsh->last_sn_update = jiffies;
 581                 }
 582                 target_sn = ifmsh->sn;
 583         } else if (is_broadcast_ether_addr(target_addr) &&
 584                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 585                 rcu_read_lock();
 586                 mpath = mesh_path_lookup(sdata, orig_addr);
 587                 if (mpath) {
 588                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 589                                 reply = true;
 590                                 target_addr = sdata->vif.addr;
 591                                 target_sn = ++ifmsh->sn;
 592                                 target_metric = 0;
 593                                 ifmsh->last_sn_update = jiffies;
 594                         }
 595                         if (root_is_gate)
 596                                 mesh_path_add_gate(mpath);
 597                 }
 598                 rcu_read_unlock();
 599         } else {
 600                 rcu_read_lock();
 601                 mpath = mesh_path_lookup(sdata, target_addr);
 602                 if (mpath) {
 603                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 604                                         SN_LT(mpath->sn, target_sn)) {
 605                                 mpath->sn = target_sn;
 606                                 mpath->flags |= MESH_PATH_SN_VALID;
 607                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 608                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 609                                 reply = true;
 610                                 target_metric = mpath->metric;
 611                                 target_sn = mpath->sn;
 612                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 613                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 614                         }
 615                 }
 616                 rcu_read_unlock();
 617         }
 618
 619         if (reply) {
 620                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 621                 ttl = ifmsh->mshcfg.element_ttl;
 622                 if (ttl != 0) {
 623                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 624                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 625                                                orig_sn, 0, target_addr,
 626                                                target_sn, mgmt->sa, 0, ttl,
 627                                                lifetime, target_metric, 0,
 628                                                sdata);
 629                 } else {
 630                         ifmsh->mshstats.dropped_frames_ttl++;
 631                 }
 632         }
 633
 634         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 635                 u32 preq_id;
 636                 u8 hopcount;
 637
 638                 ttl = PREQ_IE_TTL(preq_elem);
 639                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 640                 if (ttl <= 1) {
 641                         ifmsh->mshstats.dropped_frames_ttl++;
 642                         return;
 643                 }
 644                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 645                 --ttl;
 646                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 647                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 648                 da = (mpath && mpath->is_root) ?
 649                         mpath->rann_snd_addr : broadcast_addr;
 650
 651                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 652                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 653                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 654                 }
 655
 656                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 657                                        orig_sn, target_flags, target_addr,
 658                                        target_sn, da, hopcount, ttl, lifetime,
 659                                        orig_metric, preq_id, sdata);
 660                 if (!is_multicast_ether_addr(da))
 661                         ifmsh->mshstats.fwded_unicast++;
 662                 else
 663                         ifmsh->mshstats.fwded_mcast++;
 664                 ifmsh->mshstats.fwded_frames++;
 665         }
 666 }
 667
 668
 669 static inline struct sta_info *
 670 next_hop_deref_protected(struct mesh_path *mpath)
 671 {
 672         return rcu_dereference_protected(mpath->next_hop,
 673                                          lockdep_is_held(&mpath->state_lock));
 674 }
 675
 676
 677 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 678                                     struct ieee80211_mgmt *mgmt,
 679                                     const u8 *prep_elem, u32 metric)
 680 {
 681         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 682         struct mesh_path *mpath;
 683         const u8 *target_addr, *orig_addr;
 684         u8 ttl, hopcount, flags;
 685         u8 next_hop[ETH_ALEN];
 686         u32 target_sn, orig_sn, lifetime;
 687
 688         mhwmp_dbg(sdata, "received PREP from %pM\n",
 689                   PREP_IE_TARGET_ADDR(prep_elem));
 690
 691         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 692         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 693                 /* destination, no forwarding required */
 694                 return;
 695
 696         if (!ifmsh->mshcfg.dot11MeshForwarding)
 697                 return;
 698
 699         ttl = PREP_IE_TTL(prep_elem);
 700         if (ttl <= 1) {
 701                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 702                 return;
 703         }
 704
 705         rcu_read_lock();
 706         mpath = mesh_path_lookup(sdata, orig_addr);
 707         if (mpath)
 708                 spin_lock_bh(&mpath->state_lock);
 709         else
 710                 goto fail;
 711         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 712                 spin_unlock_bh(&mpath->state_lock);
 713                 goto fail;
 714         }
 715         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 716         spin_unlock_bh(&mpath->state_lock);
 717         --ttl;
 718         flags = PREP_IE_FLAGS(prep_elem);
 719         lifetime = PREP_IE_LIFETIME(prep_elem);
 720         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 721         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 722         target_sn = PREP_IE_TARGET_SN(prep_elem);
 723         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 724
 725         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 726                                target_addr, target_sn, next_hop, hopcount,
 727                                ttl, lifetime, metric, 0, sdata);
 728         rcu_read_unlock();
 729
 730         sdata->u.mesh.mshstats.fwded_unicast++;
 731         sdata->u.mesh.mshstats.fwded_frames++;
 732         return;
 733
 734 fail:
 735         rcu_read_unlock();
 736         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 737 }
 738
 739 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 740                                     struct ieee80211_mgmt *mgmt,
 741                                     const u8 *perr_elem)
 742 {
 743         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 744         struct mesh_path *mpath;
 745         u8 ttl;
 746         const u8 *ta, *target_addr;
 747         u32 target_sn;
 748         u16 target_rcode;
 749
 750         ta = mgmt->sa;
 751         ttl = PERR_IE_TTL(perr_elem);
 752         if (ttl <= 1) {
 753                 ifmsh->mshstats.dropped_frames_ttl++;
 754                 return;
 755         }
 756         ttl--;
 757         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 758         target_sn = PERR_IE_TARGET_SN(perr_elem);
 759         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 760
 761         rcu_read_lock();
 762         mpath = mesh_path_lookup(sdata, target_addr);
 763         if (mpath) {
 764                 struct sta_info *sta;
 765
 766                 spin_lock_bh(&mpath->state_lock);
 767                 sta = next_hop_deref_protected(mpath);
 768                 if (mpath->flags & MESH_PATH_ACTIVE &&
 769                     ether_addr_equal(ta, sta->sta.addr) &&
 770                     !(mpath->flags & MESH_PATH_FIXED) &&
 771                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 772                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 773                         mpath->flags &= ~MESH_PATH_ACTIVE;
 774                         if (target_sn != 0)
 775                                 mpath->sn = target_sn;
 776                         else
 777                                 mpath->sn += 1;
 778                         spin_unlock_bh(&mpath->state_lock);
 779                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 780                                 goto endperr;
 781                         mesh_path_error_tx(sdata, ttl, target_addr,
 782                                            target_sn, target_rcode,
 783                                            broadcast_addr);
 784                 } else
 785                         spin_unlock_bh(&mpath->state_lock);
 786         }
 787 endperr:
 788         rcu_read_unlock();
 789 }
 790
 791 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 792                                     struct ieee80211_mgmt *mgmt,
 793                                     const struct ieee80211_rann_ie *rann)
 794 {
 795         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 796         struct ieee80211_local *local = sdata->local;
 797         struct sta_info *sta;
 798         struct mesh_path *mpath;
 799         u8 ttl, flags, hopcount;
 800         const u8 *orig_addr;
 801         u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
 802         bool root_is_gate;
 803
 804         ttl = rann->rann_ttl;
 805         flags = rann->rann_flags;
 806         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 807         orig_addr = rann->rann_addr;
 808         orig_sn = le32_to_cpu(rann->rann_seq);
 809         interval = le32_to_cpu(rann->rann_interval);
 810         hopcount = rann->rann_hopcount;
 811         hopcount++;
 812         orig_metric = le32_to_cpu(rann->rann_metric);
 813
 814         /*  Ignore our own RANNs */
 815         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 816                 return;
 817
 818         mhwmp_dbg(sdata,
 819                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 820                   orig_addr, mgmt->sa, root_is_gate);
 821
 822         rcu_read_lock();
 823         sta = sta_info_get(sdata, mgmt->sa);
 824         if (!sta) {
 825                 rcu_read_unlock();
 826                 return;
 827         }
 828
 829         last_hop_metric = airtime_link_metric_get(local, sta);
 830         new_metric = orig_metric + last_hop_metric;
 831         if (new_metric < orig_metric)
 832                 new_metric = MAX_METRIC;
 833
 834         mpath = mesh_path_lookup(sdata, orig_addr);
 835         if (!mpath) {
 836                 mpath = mesh_path_add(sdata, orig_addr);
 837                 if (IS_ERR(mpath)) {
 838                         rcu_read_unlock();
 839                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 840                         return;
 841                 }
 842         }
 843
 844         if (!(SN_LT(mpath->sn, orig_sn)) &&
 845             !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
 846                 rcu_read_unlock();
 847                 return;
 848         }
 849
 850         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 851              (time_after(jiffies, mpath->last_preq_to_root +
 852                                   root_path_confirmation_jiffies(sdata)) ||
 853              time_before(jiffies, mpath->last_preq_to_root))) &&
 854              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 855                 mhwmp_dbg(sdata,
 856                           "time to refresh root mpath %pM\n",
 857                           orig_addr);
 858                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 859                 mpath->last_preq_to_root = jiffies;
 860         }
 861
 862         mpath->sn = orig_sn;
 863         mpath->rann_metric = new_metric;
 864         mpath->is_root = true;
 865         /* Recording RANNs sender address to send individually
 866          * addressed PREQs destined for root mesh STA */
 867         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 868
 869         if (root_is_gate)
 870                 mesh_path_add_gate(mpath);
 871
 872         if (ttl <= 1) {
 873                 ifmsh->mshstats.dropped_frames_ttl++;
 874                 rcu_read_unlock();
 875                 return;
 876         }
 877         ttl--;
 878
 879         if (ifmsh->mshcfg.dot11MeshForwarding) {
 880                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 881                                        orig_sn, 0, NULL, 0, broadcast_addr,
 882                                        hopcount, ttl, interval,
 883                                        new_metric, 0, sdata);
 884         }
 885
 886         rcu_read_unlock();
 887 }
 888
 889
 890 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 891                             struct ieee80211_mgmt *mgmt, size_t len)
 892 {
 893         struct ieee802_11_elems elems;
 894         size_t baselen;
 895         u32 path_metric;
 896         struct sta_info *sta;
 897
 898         /* need action_code */
 899         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 900                 return;
 901
 902         rcu_read_lock();
 903         sta = sta_info_get(sdata, mgmt->sa);
 904         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 905                 rcu_read_unlock();
 906                 return;
 907         }
 908         rcu_read_unlock();
 909
 910         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 911         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 912                                len - baselen, false, &elems);
 913
 914         if (elems.preq) {
 915                 if (elems.preq_len != 37)
 916                         /* Right now we support just 1 destination and no AE */
 917                         return;
 918                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 919                                                   MPATH_PREQ);
 920                 if (path_metric)
 921                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 922                                                 path_metric);
 923         }
 924         if (elems.prep) {
 925                 if (elems.prep_len != 31)
 926                         /* Right now we support no AE */
 927                         return;
 928                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 929                                                   MPATH_PREP);
 930                 if (path_metric)
 931                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 932                                                 path_metric);
 933         }
 934         if (elems.perr) {
 935                 if (elems.perr_len != 15)
 936                         /* Right now we support only one destination per PERR */
 937                         return;
 938                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 939         }
 940         if (elems.rann)
 941                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 942 }
 943
 944 /**
 945  * mesh_queue_preq - queue a PREQ to a given destination
 946  *
 947  * @mpath: mesh path to discover
 948  * @flags: special attributes of the PREQ to be sent
 949  *
 950  * Locking: the function must be called from within a rcu read lock block.
 951  *
 952  */
 953 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 954 {
 955         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 956         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 957         struct mesh_preq_queue *preq_node;
 958
 959         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 960         if (!preq_node) {
 961                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 962                 return;
 963         }
 964
 965         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 966         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 967                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 968                 kfree(preq_node);
 969                 if (printk_ratelimit())
 970                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 971                 return;
 972         }
 973
 974         spin_lock(&mpath->state_lock);
 975         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 976                 spin_unlock(&mpath->state_lock);
 977                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 978                 kfree(preq_node);
 979                 return;
 980         }
 981
 982         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 983         preq_node->flags = flags;
 984
 985         mpath->flags |= MESH_PATH_REQ_QUEUED;
 986         spin_unlock(&mpath->state_lock);
 987
 988         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 989         ++ifmsh->preq_queue_len;
 990         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 991
 992         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 993                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 994
 995         else if (time_before(jiffies, ifmsh->last_preq)) {
 996                 /* avoid long wait if did not send preqs for a long time
 997                  * and jiffies wrapped around
 998                  */
 999                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1000                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1001         } else
1002                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1003                                                 min_preq_int_jiff(sdata));
1004 }
1005
1006 /**
1007  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1008  *
1009  * @sdata: local mesh subif
1010  */
1011 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1012 {
1013         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1014         struct mesh_preq_queue *preq_node;
1015         struct mesh_path *mpath;
1016         u8 ttl, target_flags = 0;
1017         const u8 *da;
1018         u32 lifetime;
1019
1020         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1021         if (!ifmsh->preq_queue_len ||
1022                 time_before(jiffies, ifmsh->last_preq +
1023                                 min_preq_int_jiff(sdata))) {
1024                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1025                 return;
1026         }
1027
1028         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1029                         struct mesh_preq_queue, list);
1030         list_del(&preq_node->list);
1031         --ifmsh->preq_queue_len;
1032         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1033
1034         rcu_read_lock();
1035         mpath = mesh_path_lookup(sdata, preq_node->dst);
1036         if (!mpath)
1037                 goto enddiscovery;
1038
1039         spin_lock_bh(&mpath->state_lock);
1040         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1041                 spin_unlock_bh(&mpath->state_lock);
1042                 goto enddiscovery;
1043         }
1044         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1045         if (preq_node->flags & PREQ_Q_F_START) {
1046                 if (mpath->flags & MESH_PATH_RESOLVING) {
1047                         spin_unlock_bh(&mpath->state_lock);
1048                         goto enddiscovery;
1049                 } else {
1050                         mpath->flags &= ~MESH_PATH_RESOLVED;
1051                         mpath->flags |= MESH_PATH_RESOLVING;
1052                         mpath->discovery_retries = 0;
1053                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1054                 }
1055         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1056                         mpath->flags & MESH_PATH_RESOLVED) {
1057                 mpath->flags &= ~MESH_PATH_RESOLVING;
1058                 spin_unlock_bh(&mpath->state_lock);
1059                 goto enddiscovery;
1060         }
1061
1062         ifmsh->last_preq = jiffies;
1063
1064         if (time_after(jiffies, ifmsh->last_sn_update +
1065                                 net_traversal_jiffies(sdata)) ||
1066             time_before(jiffies, ifmsh->last_sn_update)) {
1067                 ++ifmsh->sn;
1068                 sdata->u.mesh.last_sn_update = jiffies;
1069         }
1070         lifetime = default_lifetime(sdata);
1071         ttl = sdata->u.mesh.mshcfg.element_ttl;
1072         if (ttl == 0) {
1073                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1074                 spin_unlock_bh(&mpath->state_lock);
1075                 goto enddiscovery;
1076         }
1077
1078         if (preq_node->flags & PREQ_Q_F_REFRESH)
1079                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1080         else
1081                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1082
1083         spin_unlock_bh(&mpath->state_lock);
1084         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1085         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1086                                target_flags, mpath->dst, mpath->sn, da, 0,
1087                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1088         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1089
1090 enddiscovery:
1091         rcu_read_unlock();
1092         kfree(preq_node);
1093 }
1094
1095 /**
1096  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1097  *
1098  * @skb: 802.11 frame to be sent
1099  * @sdata: network subif the frame will be sent through
1100  *
1101  * Lookup next hop for given skb and start path discovery if no
1102  * forwarding information is found.
1103  *
1104  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1105  * skb is freeed here if no mpath could be allocated.
1106  */
1107 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1108                          struct sk_buff *skb)
1109 {
1110         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1111         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1112         struct mesh_path *mpath;
1113         struct sk_buff *skb_to_free = NULL;
1114         u8 *target_addr = hdr->addr3;
1115         int err = 0;
1116
1117         /* Nulls are only sent to peers for PS and should be pre-addressed */
1118         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1119                 return 0;
1120
1121         rcu_read_lock();
1122         err = mesh_nexthop_lookup(sdata, skb);
1123         if (!err)
1124                 goto endlookup;
1125
1126         /* no nexthop found, start resolving */
1127         mpath = mesh_path_lookup(sdata, target_addr);
1128         if (!mpath) {
1129                 mpath = mesh_path_add(sdata, target_addr);
1130                 if (IS_ERR(mpath)) {
1131                         mesh_path_discard_frame(sdata, skb);
1132                         err = PTR_ERR(mpath);
1133                         goto endlookup;
1134                 }
1135         }
1136
1137         if (!(mpath->flags & MESH_PATH_RESOLVING))
1138                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1139
1140         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1141                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1142
1143         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1144         ieee80211_set_qos_hdr(sdata, skb);
1145         skb_queue_tail(&mpath->frame_queue, skb);
1146         err = -ENOENT;
1147         if (skb_to_free)
1148                 mesh_path_discard_frame(sdata, skb_to_free);
1149
1150 endlookup:
1151         rcu_read_unlock();
1152         return err;
1153 }
1154
1155 /**
1156  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1157  * this function is considered "using" the associated mpath, so preempt a path
1158  * refresh if this mpath expires soon.
1159  *
1160  * @skb: 802.11 frame to be sent
1161  * @sdata: network subif the frame will be sent through
1162  *
1163  * Returns: 0 if the next hop was found. Nonzero otherwise.
1164  */
1165 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1166                         struct sk_buff *skb)
1167 {
1168         struct mesh_path *mpath;
1169         struct sta_info *next_hop;
1170         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1171         u8 *target_addr = hdr->addr3;
1172         int err = -ENOENT;
1173
1174         rcu_read_lock();
1175         mpath = mesh_path_lookup(sdata, target_addr);
1176
1177         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1178                 goto endlookup;
1179
1180         if (time_after(jiffies,
1181                        mpath->exp_time -
1182                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1183             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1184             !(mpath->flags & MESH_PATH_RESOLVING) &&
1185             !(mpath->flags & MESH_PATH_FIXED))
1186                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1187
1188         next_hop = rcu_dereference(mpath->next_hop);
1189         if (next_hop) {
1190                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1191                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1192                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1193                 err = 0;
1194         }
1195
1196 endlookup:
1197         rcu_read_unlock();
1198         return err;
1199 }
1200
1201 void mesh_path_timer(struct timer_list *t)
1202 {
1203         struct mesh_path *mpath = from_timer(mpath, t, timer);
1204         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1205         int ret;
1206
1207         if (sdata->local->quiescing)
1208                 return;
1209
1210         spin_lock_bh(&mpath->state_lock);
1211         if (mpath->flags & MESH_PATH_RESOLVED ||
1212                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1213                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1214                 spin_unlock_bh(&mpath->state_lock);
1215         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1216                 ++mpath->discovery_retries;
1217                 mpath->discovery_timeout *= 2;
1218                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1219                 spin_unlock_bh(&mpath->state_lock);
1220                 mesh_queue_preq(mpath, 0);
1221         } else {
1222                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1223                                   MESH_PATH_RESOLVED |
1224                                   MESH_PATH_REQ_QUEUED);
1225                 mpath->exp_time = jiffies;
1226                 spin_unlock_bh(&mpath->state_lock);
1227                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1228                         ret = mesh_path_send_to_gates(mpath);
1229                         if (ret)
1230                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1231                 } else
1232                         mesh_path_flush_pending(mpath);
1233         }
1234 }
1235
1236 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1237 {
1238         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1239         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1240         u8 flags, target_flags = 0;
1241
1242         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1243                         ? RANN_FLAG_IS_GATE : 0;
1244
1245         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1246         case IEEE80211_PROACTIVE_RANN:
1247                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1248                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1249                                        0, ifmsh->mshcfg.element_ttl,
1250                                        interval, 0, 0, sdata);
1251                 break;
1252         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1253                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1254                 /* fall through */
1255         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1256                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1257                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1258                                 IEEE80211_PREQ_USN_FLAG;
1259                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1260                                        ++ifmsh->sn, target_flags,
1261                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1262                                        0, ifmsh->mshcfg.element_ttl, interval,
1263                                        0, ifmsh->preq_id++, sdata);
1264                 break;
1265         default:
1266                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1267                 return;
1268         }
1269 }