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 = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 115                       sizeof(mgmt->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 = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 246                       sizeof(mgmt->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, struct sk_buff *skb)
 299 {
 300         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 301         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 302         int failed;
 303
 304         if (!ieee80211_is_data(hdr->frame_control))
 305                 return;
 306
 307         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 308
 309         /* moving average, scaled to 100.
 310          * feed failure as 100 and success as 0
 311          */
 312         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
 313         if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
 314                         LINK_FAIL_THRESH)
 315                 mesh_plink_broken(sta);
 316 }
 317
 318 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 319                                    struct sta_info *sta)
 320 {
 321         struct rate_info rinfo;
 322         /* This should be adjusted for each device */
 323         int device_constant = 1 << ARITH_SHIFT;
 324         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 325         int s_unit = 1 << ARITH_SHIFT;
 326         int rate, err;
 327         u32 tx_time, estimated_retx;
 328         u64 result;
 329         unsigned long fail_avg =
 330                 ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
 331
 332         /* Try to get rate based on HW/SW RC algorithm.
 333          * Rate is returned in units of Kbps, correct this
 334          * to comply with airtime calculation units
 335          * Round up in case we get rate < 100Kbps
 336          */
 337         rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
 338
 339         if (rate) {
 340                 err = 0;
 341         } else {
 342                 if (fail_avg > LINK_FAIL_THRESH)
 343                         return MAX_METRIC;
 344
 345                 sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
 346                 rate = cfg80211_calculate_bitrate(&rinfo);
 347                 if (WARN_ON(!rate))
 348                         return MAX_METRIC;
 349
 350                 err = (fail_avg << ARITH_SHIFT) / 100;
 351         }
 352
 353         /* bitrate is in units of 100 Kbps, while we need rate in units of
 354          * 1Mbps. This will be corrected on tx_time computation.
 355          */
 356         tx_time = (device_constant + 10 * test_frame_len / rate);
 357         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 358         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
 359         return (u32)result;
 360 }
 361
 362 /**
 363  * hwmp_route_info_get - Update routing info to originator and transmitter
 364  *
 365  * @sdata: local mesh subif
 366  * @mgmt: mesh management frame
 367  * @hwmp_ie: hwmp information element (PREP or PREQ)
 368  * @action: type of hwmp ie
 369  *
 370  * This function updates the path routing information to the originator and the
 371  * transmitter of a HWMP PREQ or PREP frame.
 372  *
 373  * Returns: metric to frame originator or 0 if the frame should not be further
 374  * processed
 375  *
 376  * Notes: this function is the only place (besides user-provided info) where
 377  * path routing information is updated.
 378  */
 379 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 380                                struct ieee80211_mgmt *mgmt,
 381                                const u8 *hwmp_ie, enum mpath_frame_type action)
 382 {
 383         struct ieee80211_local *local = sdata->local;
 384         struct mesh_path *mpath;
 385         struct sta_info *sta;
 386         bool fresh_info;
 387         const u8 *orig_addr, *ta;
 388         u32 orig_sn, orig_metric;
 389         unsigned long orig_lifetime, exp_time;
 390         u32 last_hop_metric, new_metric;
 391         bool process = true;
 392
 393         rcu_read_lock();
 394         sta = sta_info_get(sdata, mgmt->sa);
 395         if (!sta) {
 396                 rcu_read_unlock();
 397                 return 0;
 398         }
 399
 400         last_hop_metric = airtime_link_metric_get(local, sta);
 401         /* Update and check originator routing info */
 402         fresh_info = true;
 403
 404         switch (action) {
 405         case MPATH_PREQ:
 406                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 407                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 408                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 409                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 410                 break;
 411         case MPATH_PREP:
 412                 /* Originator here refers to the MP that was the target in the
 413                  * Path Request. We divert from the nomenclature in the draft
 414                  * so that we can easily use a single function to gather path
 415                  * information from both PREQ and PREP frames.
 416                  */
 417                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 418                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 419                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 420                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 421                 break;
 422         default:
 423                 rcu_read_unlock();
 424                 return 0;
 425         }
 426         new_metric = orig_metric + last_hop_metric;
 427         if (new_metric < orig_metric)
 428                 new_metric = MAX_METRIC;
 429         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 430
 431         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 432                 /* This MP is the originator, we are not interested in this
 433                  * frame, except for updating transmitter's path info.
 434                  */
 435                 process = false;
 436                 fresh_info = false;
 437         } else {
 438                 mpath = mesh_path_lookup(sdata, orig_addr);
 439                 if (mpath) {
 440                         spin_lock_bh(&mpath->state_lock);
 441                         if (mpath->flags & MESH_PATH_FIXED)
 442                                 fresh_info = false;
 443                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 444                             (mpath->flags & MESH_PATH_SN_VALID)) {
 445                                 if (SN_GT(mpath->sn, orig_sn) ||
 446                                     (mpath->sn == orig_sn &&
 447                                      new_metric >= mpath->metric)) {
 448                                         process = false;
 449                                         fresh_info = false;
 450                                 }
 451                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 452                                 bool have_sn, newer_sn, bounced;
 453
 454                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 455                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 456                                 bounced = have_sn &&
 457                                           (SN_DELTA(orig_sn, mpath->sn) >
 458                                                         MAX_SANE_SN_DELTA);
 459
 460                                 if (!have_sn || newer_sn) {
 461                                         /* if SN is newer than what we had
 462                                          * then we can take it */;
 463                                 } else if (bounced) {
 464                                         /* if SN is way different than what
 465                                          * we had then assume the other side
 466                                          * rebooted or restarted */;
 467                                 } else {
 468                                         process = false;
 469                                         fresh_info = false;
 470                                 }
 471                         }
 472                 } else {
 473                         mpath = mesh_path_add(sdata, orig_addr);
 474                         if (IS_ERR(mpath)) {
 475                                 rcu_read_unlock();
 476                                 return 0;
 477                         }
 478                         spin_lock_bh(&mpath->state_lock);
 479                 }
 480
 481                 if (fresh_info) {
 482                         mesh_path_assign_nexthop(mpath, sta);
 483                         mpath->flags |= MESH_PATH_SN_VALID;
 484                         mpath->metric = new_metric;
 485                         mpath->sn = orig_sn;
 486                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 487                                           ?  mpath->exp_time : exp_time;
 488                         mesh_path_activate(mpath);
 489                         spin_unlock_bh(&mpath->state_lock);
 490                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 491                         /* init it at a low value - 0 start is tricky */
 492                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 493                         mesh_path_tx_pending(mpath);
 494                         /* draft says preq_id should be saved to, but there does
 495                          * not seem to be any use for it, skipping by now
 496                          */
 497                 } else
 498                         spin_unlock_bh(&mpath->state_lock);
 499         }
 500
 501         /* Update and check transmitter routing info */
 502         ta = mgmt->sa;
 503         if (ether_addr_equal(orig_addr, ta))
 504                 fresh_info = false;
 505         else {
 506                 fresh_info = true;
 507
 508                 mpath = mesh_path_lookup(sdata, ta);
 509                 if (mpath) {
 510                         spin_lock_bh(&mpath->state_lock);
 511                         if ((mpath->flags & MESH_PATH_FIXED) ||
 512                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 513                                         (last_hop_metric > mpath->metric)))
 514                                 fresh_info = false;
 515                 } else {
 516                         mpath = mesh_path_add(sdata, ta);
 517                         if (IS_ERR(mpath)) {
 518                                 rcu_read_unlock();
 519                                 return 0;
 520                         }
 521                         spin_lock_bh(&mpath->state_lock);
 522                 }
 523
 524                 if (fresh_info) {
 525                         mesh_path_assign_nexthop(mpath, sta);
 526                         mpath->metric = last_hop_metric;
 527                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 528                                           ?  mpath->exp_time : exp_time;
 529                         mesh_path_activate(mpath);
 530                         spin_unlock_bh(&mpath->state_lock);
 531                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 532                         /* init it at a low value - 0 start is tricky */
 533                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 534                         mesh_path_tx_pending(mpath);
 535                 } else
 536                         spin_unlock_bh(&mpath->state_lock);
 537         }
 538
 539         rcu_read_unlock();
 540
 541         return process ? new_metric : 0;
 542 }
 543
 544 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 545                                     struct ieee80211_mgmt *mgmt,
 546                                     const u8 *preq_elem, u32 orig_metric)
 547 {
 548         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 549         struct mesh_path *mpath = NULL;
 550         const u8 *target_addr, *orig_addr;
 551         const u8 *da;
 552         u8 target_flags, ttl, flags;
 553         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 554         bool reply = false;
 555         bool forward = true;
 556         bool root_is_gate;
 557
 558         /* Update target SN, if present */
 559         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 560         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 561         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 562         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 563         target_flags = PREQ_IE_TARGET_F(preq_elem);
 564         /* Proactive PREQ gate announcements */
 565         flags = PREQ_IE_FLAGS(preq_elem);
 566         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 567
 568         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 569
 570         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 571                 mhwmp_dbg(sdata, "PREQ is for us\n");
 572                 forward = false;
 573                 reply = true;
 574                 target_metric = 0;
 575                 if (time_after(jiffies, ifmsh->last_sn_update +
 576                                         net_traversal_jiffies(sdata)) ||
 577                     time_before(jiffies, ifmsh->last_sn_update)) {
 578                         ++ifmsh->sn;
 579                         ifmsh->last_sn_update = jiffies;
 580                 }
 581                 target_sn = ifmsh->sn;
 582         } else if (is_broadcast_ether_addr(target_addr) &&
 583                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 584                 rcu_read_lock();
 585                 mpath = mesh_path_lookup(sdata, orig_addr);
 586                 if (mpath) {
 587                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 588                                 reply = true;
 589                                 target_addr = sdata->vif.addr;
 590                                 target_sn = ++ifmsh->sn;
 591                                 target_metric = 0;
 592                                 ifmsh->last_sn_update = jiffies;
 593                         }
 594                         if (root_is_gate)
 595                                 mesh_path_add_gate(mpath);
 596                 }
 597                 rcu_read_unlock();
 598         } else {
 599                 rcu_read_lock();
 600                 mpath = mesh_path_lookup(sdata, target_addr);
 601                 if (mpath) {
 602                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 603                                         SN_LT(mpath->sn, target_sn)) {
 604                                 mpath->sn = target_sn;
 605                                 mpath->flags |= MESH_PATH_SN_VALID;
 606                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 607                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 608                                 reply = true;
 609                                 target_metric = mpath->metric;
 610                                 target_sn = mpath->sn;
 611                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 612                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 613                         }
 614                 }
 615                 rcu_read_unlock();
 616         }
 617
 618         if (reply) {
 619                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 620                 ttl = ifmsh->mshcfg.element_ttl;
 621                 if (ttl != 0) {
 622                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 623                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 624                                                orig_sn, 0, target_addr,
 625                                                target_sn, mgmt->sa, 0, ttl,
 626                                                lifetime, target_metric, 0,
 627                                                sdata);
 628                 } else {
 629                         ifmsh->mshstats.dropped_frames_ttl++;
 630                 }
 631         }
 632
 633         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 634                 u32 preq_id;
 635                 u8 hopcount;
 636
 637                 ttl = PREQ_IE_TTL(preq_elem);
 638                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 639                 if (ttl <= 1) {
 640                         ifmsh->mshstats.dropped_frames_ttl++;
 641                         return;
 642                 }
 643                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 644                 --ttl;
 645                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 646                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 647                 da = (mpath && mpath->is_root) ?
 648                         mpath->rann_snd_addr : broadcast_addr;
 649
 650                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 651                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 652                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 653                 }
 654
 655                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 656                                        orig_sn, target_flags, target_addr,
 657                                        target_sn, da, hopcount, ttl, lifetime,
 658                                        orig_metric, preq_id, sdata);
 659                 if (!is_multicast_ether_addr(da))
 660                         ifmsh->mshstats.fwded_unicast++;
 661                 else
 662                         ifmsh->mshstats.fwded_mcast++;
 663                 ifmsh->mshstats.fwded_frames++;
 664         }
 665 }
 666
 667
 668 static inline struct sta_info *
 669 next_hop_deref_protected(struct mesh_path *mpath)
 670 {
 671         return rcu_dereference_protected(mpath->next_hop,
 672                                          lockdep_is_held(&mpath->state_lock));
 673 }
 674
 675
 676 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 677                                     struct ieee80211_mgmt *mgmt,
 678                                     const u8 *prep_elem, u32 metric)
 679 {
 680         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 681         struct mesh_path *mpath;
 682         const u8 *target_addr, *orig_addr;
 683         u8 ttl, hopcount, flags;
 684         u8 next_hop[ETH_ALEN];
 685         u32 target_sn, orig_sn, lifetime;
 686
 687         mhwmp_dbg(sdata, "received PREP from %pM\n",
 688                   PREP_IE_TARGET_ADDR(prep_elem));
 689
 690         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 691         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 692                 /* destination, no forwarding required */
 693                 return;
 694
 695         if (!ifmsh->mshcfg.dot11MeshForwarding)
 696                 return;
 697
 698         ttl = PREP_IE_TTL(prep_elem);
 699         if (ttl <= 1) {
 700                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 701                 return;
 702         }
 703
 704         rcu_read_lock();
 705         mpath = mesh_path_lookup(sdata, orig_addr);
 706         if (mpath)
 707                 spin_lock_bh(&mpath->state_lock);
 708         else
 709                 goto fail;
 710         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 711                 spin_unlock_bh(&mpath->state_lock);
 712                 goto fail;
 713         }
 714         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 715         spin_unlock_bh(&mpath->state_lock);
 716         --ttl;
 717         flags = PREP_IE_FLAGS(prep_elem);
 718         lifetime = PREP_IE_LIFETIME(prep_elem);
 719         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 720         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 721         target_sn = PREP_IE_TARGET_SN(prep_elem);
 722         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 723
 724         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 725                                target_addr, target_sn, next_hop, hopcount,
 726                                ttl, lifetime, metric, 0, sdata);
 727         rcu_read_unlock();
 728
 729         sdata->u.mesh.mshstats.fwded_unicast++;
 730         sdata->u.mesh.mshstats.fwded_frames++;
 731         return;
 732
 733 fail:
 734         rcu_read_unlock();
 735         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 736 }
 737
 738 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 739                                     struct ieee80211_mgmt *mgmt,
 740                                     const u8 *perr_elem)
 741 {
 742         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 743         struct mesh_path *mpath;
 744         u8 ttl;
 745         const u8 *ta, *target_addr;
 746         u32 target_sn;
 747         u16 target_rcode;
 748
 749         ta = mgmt->sa;
 750         ttl = PERR_IE_TTL(perr_elem);
 751         if (ttl <= 1) {
 752                 ifmsh->mshstats.dropped_frames_ttl++;
 753                 return;
 754         }
 755         ttl--;
 756         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 757         target_sn = PERR_IE_TARGET_SN(perr_elem);
 758         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 759
 760         rcu_read_lock();
 761         mpath = mesh_path_lookup(sdata, target_addr);
 762         if (mpath) {
 763                 struct sta_info *sta;
 764
 765                 spin_lock_bh(&mpath->state_lock);
 766                 sta = next_hop_deref_protected(mpath);
 767                 if (mpath->flags & MESH_PATH_ACTIVE &&
 768                     ether_addr_equal(ta, sta->sta.addr) &&
 769                     !(mpath->flags & MESH_PATH_FIXED) &&
 770                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 771                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 772                         mpath->flags &= ~MESH_PATH_ACTIVE;
 773                         if (target_sn != 0)
 774                                 mpath->sn = target_sn;
 775                         else
 776                                 mpath->sn += 1;
 777                         spin_unlock_bh(&mpath->state_lock);
 778                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 779                                 goto endperr;
 780                         mesh_path_error_tx(sdata, ttl, target_addr,
 781                                            target_sn, target_rcode,
 782                                            broadcast_addr);
 783                 } else
 784                         spin_unlock_bh(&mpath->state_lock);
 785         }
 786 endperr:
 787         rcu_read_unlock();
 788 }
 789
 790 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 791                                     struct ieee80211_mgmt *mgmt,
 792                                     const struct ieee80211_rann_ie *rann)
 793 {
 794         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 795         struct ieee80211_local *local = sdata->local;
 796         struct sta_info *sta;
 797         struct mesh_path *mpath;
 798         u8 ttl, flags, hopcount;
 799         const u8 *orig_addr;
 800         u32 orig_sn, metric, metric_txsta, interval;
 801         bool root_is_gate;
 802
 803         ttl = rann->rann_ttl;
 804         flags = rann->rann_flags;
 805         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 806         orig_addr = rann->rann_addr;
 807         orig_sn = le32_to_cpu(rann->rann_seq);
 808         interval = le32_to_cpu(rann->rann_interval);
 809         hopcount = rann->rann_hopcount;
 810         hopcount++;
 811         metric = le32_to_cpu(rann->rann_metric);
 812
 813         /*  Ignore our own RANNs */
 814         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 815                 return;
 816
 817         mhwmp_dbg(sdata,
 818                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 819                   orig_addr, mgmt->sa, root_is_gate);
 820
 821         rcu_read_lock();
 822         sta = sta_info_get(sdata, mgmt->sa);
 823         if (!sta) {
 824                 rcu_read_unlock();
 825                 return;
 826         }
 827
 828         metric_txsta = airtime_link_metric_get(local, sta);
 829
 830         mpath = mesh_path_lookup(sdata, orig_addr);
 831         if (!mpath) {
 832                 mpath = mesh_path_add(sdata, orig_addr);
 833                 if (IS_ERR(mpath)) {
 834                         rcu_read_unlock();
 835                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 836                         return;
 837                 }
 838         }
 839
 840         if (!(SN_LT(mpath->sn, orig_sn)) &&
 841             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 842                 rcu_read_unlock();
 843                 return;
 844         }
 845
 846         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 847              (time_after(jiffies, mpath->last_preq_to_root +
 848                                   root_path_confirmation_jiffies(sdata)) ||
 849              time_before(jiffies, mpath->last_preq_to_root))) &&
 850              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 851                 mhwmp_dbg(sdata,
 852                           "time to refresh root mpath %pM\n",
 853                           orig_addr);
 854                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 855                 mpath->last_preq_to_root = jiffies;
 856         }
 857
 858         mpath->sn = orig_sn;
 859         mpath->rann_metric = metric + metric_txsta;
 860         mpath->is_root = true;
 861         /* Recording RANNs sender address to send individually
 862          * addressed PREQs destined for root mesh STA */
 863         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 864
 865         if (root_is_gate)
 866                 mesh_path_add_gate(mpath);
 867
 868         if (ttl <= 1) {
 869                 ifmsh->mshstats.dropped_frames_ttl++;
 870                 rcu_read_unlock();
 871                 return;
 872         }
 873         ttl--;
 874
 875         if (ifmsh->mshcfg.dot11MeshForwarding) {
 876                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 877                                        orig_sn, 0, NULL, 0, broadcast_addr,
 878                                        hopcount, ttl, interval,
 879                                        metric + metric_txsta, 0, sdata);
 880         }
 881
 882         rcu_read_unlock();
 883 }
 884
 885
 886 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 887                             struct ieee80211_mgmt *mgmt, size_t len)
 888 {
 889         struct ieee802_11_elems elems;
 890         size_t baselen;
 891         u32 path_metric;
 892         struct sta_info *sta;
 893
 894         /* need action_code */
 895         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 896                 return;
 897
 898         rcu_read_lock();
 899         sta = sta_info_get(sdata, mgmt->sa);
 900         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 901                 rcu_read_unlock();
 902                 return;
 903         }
 904         rcu_read_unlock();
 905
 906         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 907         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 908                                len - baselen, false, &elems);
 909
 910         if (elems.preq) {
 911                 if (elems.preq_len != 37)
 912                         /* Right now we support just 1 destination and no AE */
 913                         return;
 914                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 915                                                   MPATH_PREQ);
 916                 if (path_metric)
 917                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 918                                                 path_metric);
 919         }
 920         if (elems.prep) {
 921                 if (elems.prep_len != 31)
 922                         /* Right now we support no AE */
 923                         return;
 924                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 925                                                   MPATH_PREP);
 926                 if (path_metric)
 927                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 928                                                 path_metric);
 929         }
 930         if (elems.perr) {
 931                 if (elems.perr_len != 15)
 932                         /* Right now we support only one destination per PERR */
 933                         return;
 934                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 935         }
 936         if (elems.rann)
 937                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 938 }
 939
 940 /**
 941  * mesh_queue_preq - queue a PREQ to a given destination
 942  *
 943  * @mpath: mesh path to discover
 944  * @flags: special attributes of the PREQ to be sent
 945  *
 946  * Locking: the function must be called from within a rcu read lock block.
 947  *
 948  */
 949 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 950 {
 951         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 952         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 953         struct mesh_preq_queue *preq_node;
 954
 955         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 956         if (!preq_node) {
 957                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 958                 return;
 959         }
 960
 961         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 962         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 963                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 964                 kfree(preq_node);
 965                 if (printk_ratelimit())
 966                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 967                 return;
 968         }
 969
 970         spin_lock(&mpath->state_lock);
 971         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 972                 spin_unlock(&mpath->state_lock);
 973                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 974                 kfree(preq_node);
 975                 return;
 976         }
 977
 978         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 979         preq_node->flags = flags;
 980
 981         mpath->flags |= MESH_PATH_REQ_QUEUED;
 982         spin_unlock(&mpath->state_lock);
 983
 984         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 985         ++ifmsh->preq_queue_len;
 986         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 987
 988         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 989                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 990
 991         else if (time_before(jiffies, ifmsh->last_preq)) {
 992                 /* avoid long wait if did not send preqs for a long time
 993                  * and jiffies wrapped around
 994                  */
 995                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 996                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 997         } else
 998                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 999                                                 min_preq_int_jiff(sdata));
1000 }
1001
1002 /**
1003  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1004  *
1005  * @sdata: local mesh subif
1006  */
1007 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1008 {
1009         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1010         struct mesh_preq_queue *preq_node;
1011         struct mesh_path *mpath;
1012         u8 ttl, target_flags = 0;
1013         const u8 *da;
1014         u32 lifetime;
1015
1016         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1017         if (!ifmsh->preq_queue_len ||
1018                 time_before(jiffies, ifmsh->last_preq +
1019                                 min_preq_int_jiff(sdata))) {
1020                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1021                 return;
1022         }
1023
1024         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1025                         struct mesh_preq_queue, list);
1026         list_del(&preq_node->list);
1027         --ifmsh->preq_queue_len;
1028         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1029
1030         rcu_read_lock();
1031         mpath = mesh_path_lookup(sdata, preq_node->dst);
1032         if (!mpath)
1033                 goto enddiscovery;
1034
1035         spin_lock_bh(&mpath->state_lock);
1036         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1037                 spin_unlock_bh(&mpath->state_lock);
1038                 goto enddiscovery;
1039         }
1040         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1041         if (preq_node->flags & PREQ_Q_F_START) {
1042                 if (mpath->flags & MESH_PATH_RESOLVING) {
1043                         spin_unlock_bh(&mpath->state_lock);
1044                         goto enddiscovery;
1045                 } else {
1046                         mpath->flags &= ~MESH_PATH_RESOLVED;
1047                         mpath->flags |= MESH_PATH_RESOLVING;
1048                         mpath->discovery_retries = 0;
1049                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1050                 }
1051         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1052                         mpath->flags & MESH_PATH_RESOLVED) {
1053                 mpath->flags &= ~MESH_PATH_RESOLVING;
1054                 spin_unlock_bh(&mpath->state_lock);
1055                 goto enddiscovery;
1056         }
1057
1058         ifmsh->last_preq = jiffies;
1059
1060         if (time_after(jiffies, ifmsh->last_sn_update +
1061                                 net_traversal_jiffies(sdata)) ||
1062             time_before(jiffies, ifmsh->last_sn_update)) {
1063                 ++ifmsh->sn;
1064                 sdata->u.mesh.last_sn_update = jiffies;
1065         }
1066         lifetime = default_lifetime(sdata);
1067         ttl = sdata->u.mesh.mshcfg.element_ttl;
1068         if (ttl == 0) {
1069                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1070                 spin_unlock_bh(&mpath->state_lock);
1071                 goto enddiscovery;
1072         }
1073
1074         if (preq_node->flags & PREQ_Q_F_REFRESH)
1075                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1076         else
1077                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1078
1079         spin_unlock_bh(&mpath->state_lock);
1080         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1081         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1082                                target_flags, mpath->dst, mpath->sn, da, 0,
1083                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1084         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1085
1086 enddiscovery:
1087         rcu_read_unlock();
1088         kfree(preq_node);
1089 }
1090
1091 /**
1092  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1093  *
1094  * @skb: 802.11 frame to be sent
1095  * @sdata: network subif the frame will be sent through
1096  *
1097  * Lookup next hop for given skb and start path discovery if no
1098  * forwarding information is found.
1099  *
1100  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1101  * skb is freeed here if no mpath could be allocated.
1102  */
1103 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1104                          struct sk_buff *skb)
1105 {
1106         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1107         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1108         struct mesh_path *mpath;
1109         struct sk_buff *skb_to_free = NULL;
1110         u8 *target_addr = hdr->addr3;
1111         int err = 0;
1112
1113         /* Nulls are only sent to peers for PS and should be pre-addressed */
1114         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1115                 return 0;
1116
1117         rcu_read_lock();
1118         err = mesh_nexthop_lookup(sdata, skb);
1119         if (!err)
1120                 goto endlookup;
1121
1122         /* no nexthop found, start resolving */
1123         mpath = mesh_path_lookup(sdata, target_addr);
1124         if (!mpath) {
1125                 mpath = mesh_path_add(sdata, target_addr);
1126                 if (IS_ERR(mpath)) {
1127                         mesh_path_discard_frame(sdata, skb);
1128                         err = PTR_ERR(mpath);
1129                         goto endlookup;
1130                 }
1131         }
1132
1133         if (!(mpath->flags & MESH_PATH_RESOLVING))
1134                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1135
1136         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1137                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1138
1139         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1140         ieee80211_set_qos_hdr(sdata, skb);
1141         skb_queue_tail(&mpath->frame_queue, skb);
1142         err = -ENOENT;
1143         if (skb_to_free)
1144                 mesh_path_discard_frame(sdata, skb_to_free);
1145
1146 endlookup:
1147         rcu_read_unlock();
1148         return err;
1149 }
1150
1151 /**
1152  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1153  * this function is considered "using" the associated mpath, so preempt a path
1154  * refresh if this mpath expires soon.
1155  *
1156  * @skb: 802.11 frame to be sent
1157  * @sdata: network subif the frame will be sent through
1158  *
1159  * Returns: 0 if the next hop was found. Nonzero otherwise.
1160  */
1161 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1162                         struct sk_buff *skb)
1163 {
1164         struct mesh_path *mpath;
1165         struct sta_info *next_hop;
1166         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1167         u8 *target_addr = hdr->addr3;
1168         int err = -ENOENT;
1169
1170         rcu_read_lock();
1171         mpath = mesh_path_lookup(sdata, target_addr);
1172
1173         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1174                 goto endlookup;
1175
1176         if (time_after(jiffies,
1177                        mpath->exp_time -
1178                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1179             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1180             !(mpath->flags & MESH_PATH_RESOLVING) &&
1181             !(mpath->flags & MESH_PATH_FIXED))
1182                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1183
1184         next_hop = rcu_dereference(mpath->next_hop);
1185         if (next_hop) {
1186                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1187                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1188                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1189                 err = 0;
1190         }
1191
1192 endlookup:
1193         rcu_read_unlock();
1194         return err;
1195 }
1196
1197 void mesh_path_timer(unsigned long data)
1198 {
1199         struct mesh_path *mpath = (void *) data;
1200         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1201         int ret;
1202
1203         if (sdata->local->quiescing)
1204                 return;
1205
1206         spin_lock_bh(&mpath->state_lock);
1207         if (mpath->flags & MESH_PATH_RESOLVED ||
1208                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1209                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1210                 spin_unlock_bh(&mpath->state_lock);
1211         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1212                 ++mpath->discovery_retries;
1213                 mpath->discovery_timeout *= 2;
1214                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1215                 spin_unlock_bh(&mpath->state_lock);
1216                 mesh_queue_preq(mpath, 0);
1217         } else {
1218                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1219                                   MESH_PATH_RESOLVED |
1220                                   MESH_PATH_REQ_QUEUED);
1221                 mpath->exp_time = jiffies;
1222                 spin_unlock_bh(&mpath->state_lock);
1223                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1224                         ret = mesh_path_send_to_gates(mpath);
1225                         if (ret)
1226                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1227                 } else
1228                         mesh_path_flush_pending(mpath);
1229         }
1230 }
1231
1232 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1233 {
1234         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1235         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1236         u8 flags, target_flags = 0;
1237
1238         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1239                         ? RANN_FLAG_IS_GATE : 0;
1240
1241         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1242         case IEEE80211_PROACTIVE_RANN:
1243                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1244                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1245                                        0, ifmsh->mshcfg.element_ttl,
1246                                        interval, 0, 0, sdata);
1247                 break;
1248         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1249                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1250         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1251                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1252                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1253                                 IEEE80211_PREQ_USN_FLAG;
1254                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1255                                        ++ifmsh->sn, target_flags,
1256                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1257                                        0, ifmsh->mshcfg.element_ttl, interval,
1258                                        0, ifmsh->preq_id++, sdata);
1259                 break;
1260         default:
1261                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1262                 return;
1263         }
1264 }