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
  20 #define MAX_PREQ_QUEUE_LEN      64
  21
  22 static void mesh_queue_preq(struct mesh_path *, u8);
  23
  24 static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
  25 {
  26         if (ae)
  27                 offset += 6;
  28         return get_unaligned_le32(preq_elem + offset);
  29 }
  30
  31 static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
  32 {
  33         if (ae)
  34                 offset += 6;
  35         return get_unaligned_le16(preq_elem + offset);
  36 }
  37
  38 /* HWMP IE processing macros */
  39 #define AE_F                    (1<<6)
  40 #define AE_F_SET(x)             (*x & AE_F)
  41 #define PREQ_IE_FLAGS(x)        (*(x))
  42 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  43 #define PREQ_IE_TTL(x)          (*(x + 2))
  44 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  45 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  46 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  47 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  48 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  49 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  50 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  51 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  52
  53
  54 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  55 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  56 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  57 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  58 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  59 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  60 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  61 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  62 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  63
  64 #define PERR_IE_TTL(x)          (*(x))
  65 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  66 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  67 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  68 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  69
  70 #define MSEC_TO_TU(x) (x*1000/1024)
  71 #define SN_GT(x, y) ((s32)(y - x) < 0)
  72 #define SN_LT(x, y) ((s32)(x - y) < 0)
  73 #define MAX_SANE_SN_DELTA 32
  74
  75 static inline u32 SN_DELTA(u32 x, u32 y)
  76 {
  77         return x >= y ? x - y : y - x;
  78 }
  79
  80 #define net_traversal_jiffies(s) \
  81         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  82 #define default_lifetime(s) \
  83         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  84 #define min_preq_int_jiff(s) \
  85         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  86 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  87 #define disc_timeout_jiff(s) \
  88         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  89 #define root_path_confirmation_jiffies(s) \
  90         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  91
  92 enum mpath_frame_type {
  93         MPATH_PREQ = 0,
  94         MPATH_PREP,
  95         MPATH_PERR,
  96         MPATH_RANN
  97 };
  98
  99 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 100
 101 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 102                                   const u8 *orig_addr, u32 orig_sn,
 103                                   u8 target_flags, const u8 *target,
 104                                   u32 target_sn, const u8 *da,
 105                                   u8 hop_count, u8 ttl,
 106                                   u32 lifetime, u32 metric, u32 preq_id,
 107                                   struct ieee80211_sub_if_data *sdata)
 108 {
 109         struct ieee80211_local *local = sdata->local;
 110         struct sk_buff *skb;
 111         struct ieee80211_mgmt *mgmt;
 112         u8 *pos, ie_len;
 113         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 114                       sizeof(mgmt->u.action.u.mesh_action);
 115
 116         skb = dev_alloc_skb(local->tx_headroom +
 117                             hdr_len +
 118                             2 + 37); /* max HWMP IE */
 119         if (!skb)
 120                 return -1;
 121         skb_reserve(skb, local->tx_headroom);
 122         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 123         memset(mgmt, 0, 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 = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 260         memset(mgmt, 0, hdr_len);
 261         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 262                                           IEEE80211_STYPE_ACTION);
 263
 264         memcpy(mgmt->da, ra, ETH_ALEN);
 265         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 266         /* BSSID == SA */
 267         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 268         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 269         mgmt->u.action.u.mesh_action.action_code =
 270                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 271         ie_len = 15;
 272         pos = skb_put(skb, 2 + ie_len);
 273         *pos++ = WLAN_EID_PERR;
 274         *pos++ = ie_len;
 275         /* ttl */
 276         *pos++ = ttl;
 277         /* number of destinations */
 278         *pos++ = 1;
 279         /* Flags field has AE bit only as defined in
 280          * sec 8.4.2.117 IEEE802.11-2012
 281          */
 282         *pos = 0;
 283         pos++;
 284         memcpy(pos, target, ETH_ALEN);
 285         pos += ETH_ALEN;
 286         put_unaligned_le32(target_sn, pos);
 287         pos += 4;
 288         put_unaligned_le16(target_rcode, pos);
 289
 290         /* see note in function header */
 291         prepare_frame_for_deferred_tx(sdata, skb);
 292         ifmsh->next_perr = TU_TO_EXP_TIME(
 293                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 294         ieee80211_add_pending_skb(local, skb);
 295         return 0;
 296 }
 297
 298 void ieee80211s_update_metric(struct ieee80211_local *local,
 299                 struct sta_info *sta, struct sk_buff *skb)
 300 {
 301         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 302         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 303         int failed;
 304
 305         if (!ieee80211_is_data(hdr->frame_control))
 306                 return;
 307
 308         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 309
 310         /* moving average, scaled to 100 */
 311         sta->mesh->fail_avg =
 312                 ((80 * sta->mesh->fail_avg + 5) / 100 + 20 * failed);
 313         if (sta->mesh->fail_avg > 95)
 314                 mesh_plink_broken(sta);
 315 }
 316
 317 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 318                                    struct sta_info *sta)
 319 {
 320         struct rate_info rinfo;
 321         /* This should be adjusted for each device */
 322         int device_constant = 1 << ARITH_SHIFT;
 323         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 324         int s_unit = 1 << ARITH_SHIFT;
 325         int rate, err;
 326         u32 tx_time, estimated_retx;
 327         u64 result;
 328
 329         if (sta->mesh->fail_avg >= 100)
 330                 return MAX_METRIC;
 331
 332         sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
 333         rate = cfg80211_calculate_bitrate(&rinfo);
 334         if (WARN_ON(!rate))
 335                 return MAX_METRIC;
 336
 337         err = (sta->mesh->fail_avg << ARITH_SHIFT) / 100;
 338
 339         /* bitrate is in units of 100 Kbps, while we need rate in units of
 340          * 1Mbps. This will be corrected on tx_time computation.
 341          */
 342         tx_time = (device_constant + 10 * test_frame_len / rate);
 343         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 344         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 345         return (u32)result;
 346 }
 347
 348 /**
 349  * hwmp_route_info_get - Update routing info to originator and transmitter
 350  *
 351  * @sdata: local mesh subif
 352  * @mgmt: mesh management frame
 353  * @hwmp_ie: hwmp information element (PREP or PREQ)
 354  * @action: type of hwmp ie
 355  *
 356  * This function updates the path routing information to the originator and the
 357  * transmitter of a HWMP PREQ or PREP frame.
 358  *
 359  * Returns: metric to frame originator or 0 if the frame should not be further
 360  * processed
 361  *
 362  * Notes: this function is the only place (besides user-provided info) where
 363  * path routing information is updated.
 364  */
 365 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 366                                struct ieee80211_mgmt *mgmt,
 367                                const u8 *hwmp_ie, enum mpath_frame_type action)
 368 {
 369         struct ieee80211_local *local = sdata->local;
 370         struct mesh_path *mpath;
 371         struct sta_info *sta;
 372         bool fresh_info;
 373         const u8 *orig_addr, *ta;
 374         u32 orig_sn, orig_metric;
 375         unsigned long orig_lifetime, exp_time;
 376         u32 last_hop_metric, new_metric;
 377         bool process = true;
 378
 379         rcu_read_lock();
 380         sta = sta_info_get(sdata, mgmt->sa);
 381         if (!sta) {
 382                 rcu_read_unlock();
 383                 return 0;
 384         }
 385
 386         last_hop_metric = airtime_link_metric_get(local, sta);
 387         /* Update and check originator routing info */
 388         fresh_info = true;
 389
 390         switch (action) {
 391         case MPATH_PREQ:
 392                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 393                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 394                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 395                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 396                 break;
 397         case MPATH_PREP:
 398                 /* Originator here refers to the MP that was the target in the
 399                  * Path Request. We divert from the nomenclature in the draft
 400                  * so that we can easily use a single function to gather path
 401                  * information from both PREQ and PREP frames.
 402                  */
 403                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 404                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 405                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 406                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 407                 break;
 408         default:
 409                 rcu_read_unlock();
 410                 return 0;
 411         }
 412         new_metric = orig_metric + last_hop_metric;
 413         if (new_metric < orig_metric)
 414                 new_metric = MAX_METRIC;
 415         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 416
 417         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 418                 /* This MP is the originator, we are not interested in this
 419                  * frame, except for updating transmitter's path info.
 420                  */
 421                 process = false;
 422                 fresh_info = false;
 423         } else {
 424                 mpath = mesh_path_lookup(sdata, orig_addr);
 425                 if (mpath) {
 426                         spin_lock_bh(&mpath->state_lock);
 427                         if (mpath->flags & MESH_PATH_FIXED)
 428                                 fresh_info = false;
 429                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 430                             (mpath->flags & MESH_PATH_SN_VALID)) {
 431                                 if (SN_GT(mpath->sn, orig_sn) ||
 432                                     (mpath->sn == orig_sn &&
 433                                      new_metric >= mpath->metric)) {
 434                                         process = false;
 435                                         fresh_info = false;
 436                                 }
 437                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 438                                 bool have_sn, newer_sn, bounced;
 439
 440                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 441                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 442                                 bounced = have_sn &&
 443                                           (SN_DELTA(orig_sn, mpath->sn) >
 444                                                         MAX_SANE_SN_DELTA);
 445
 446                                 if (!have_sn || newer_sn) {
 447                                         /* if SN is newer than what we had
 448                                          * then we can take it */;
 449                                 } else if (bounced) {
 450                                         /* if SN is way different than what
 451                                          * we had then assume the other side
 452                                          * rebooted or restarted */;
 453                                 } else {
 454                                         process = false;
 455                                         fresh_info = false;
 456                                 }
 457                         }
 458                 } else {
 459                         mpath = mesh_path_add(sdata, orig_addr);
 460                         if (IS_ERR(mpath)) {
 461                                 rcu_read_unlock();
 462                                 return 0;
 463                         }
 464                         spin_lock_bh(&mpath->state_lock);
 465                 }
 466
 467                 if (fresh_info) {
 468                         mesh_path_assign_nexthop(mpath, sta);
 469                         mpath->flags |= MESH_PATH_SN_VALID;
 470                         mpath->metric = new_metric;
 471                         mpath->sn = orig_sn;
 472                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 473                                           ?  mpath->exp_time : exp_time;
 474                         mesh_path_activate(mpath);
 475                         spin_unlock_bh(&mpath->state_lock);
 476                         mesh_path_tx_pending(mpath);
 477                         /* draft says preq_id should be saved to, but there does
 478                          * not seem to be any use for it, skipping by now
 479                          */
 480                 } else
 481                         spin_unlock_bh(&mpath->state_lock);
 482         }
 483
 484         /* Update and check transmitter routing info */
 485         ta = mgmt->sa;
 486         if (ether_addr_equal(orig_addr, ta))
 487                 fresh_info = false;
 488         else {
 489                 fresh_info = true;
 490
 491                 mpath = mesh_path_lookup(sdata, ta);
 492                 if (mpath) {
 493                         spin_lock_bh(&mpath->state_lock);
 494                         if ((mpath->flags & MESH_PATH_FIXED) ||
 495                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 496                                         (last_hop_metric > mpath->metric)))
 497                                 fresh_info = false;
 498                 } else {
 499                         mpath = mesh_path_add(sdata, ta);
 500                         if (IS_ERR(mpath)) {
 501                                 rcu_read_unlock();
 502                                 return 0;
 503                         }
 504                         spin_lock_bh(&mpath->state_lock);
 505                 }
 506
 507                 if (fresh_info) {
 508                         mesh_path_assign_nexthop(mpath, sta);
 509                         mpath->metric = last_hop_metric;
 510                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 511                                           ?  mpath->exp_time : exp_time;
 512                         mesh_path_activate(mpath);
 513                         spin_unlock_bh(&mpath->state_lock);
 514                         mesh_path_tx_pending(mpath);
 515                 } else
 516                         spin_unlock_bh(&mpath->state_lock);
 517         }
 518
 519         rcu_read_unlock();
 520
 521         return process ? new_metric : 0;
 522 }
 523
 524 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 525                                     struct ieee80211_mgmt *mgmt,
 526                                     const u8 *preq_elem, u32 orig_metric)
 527 {
 528         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 529         struct mesh_path *mpath = NULL;
 530         const u8 *target_addr, *orig_addr;
 531         const u8 *da;
 532         u8 target_flags, ttl, flags;
 533         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 534         bool reply = false;
 535         bool forward = true;
 536         bool root_is_gate;
 537
 538         /* Update target SN, if present */
 539         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 540         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 541         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 542         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 543         target_flags = PREQ_IE_TARGET_F(preq_elem);
 544         /* Proactive PREQ gate announcements */
 545         flags = PREQ_IE_FLAGS(preq_elem);
 546         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 547
 548         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 549
 550         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 551                 mhwmp_dbg(sdata, "PREQ is for us\n");
 552                 forward = false;
 553                 reply = true;
 554                 target_metric = 0;
 555                 if (time_after(jiffies, ifmsh->last_sn_update +
 556                                         net_traversal_jiffies(sdata)) ||
 557                     time_before(jiffies, ifmsh->last_sn_update)) {
 558                         ++ifmsh->sn;
 559                         ifmsh->last_sn_update = jiffies;
 560                 }
 561                 target_sn = ifmsh->sn;
 562         } else if (is_broadcast_ether_addr(target_addr) &&
 563                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 564                 rcu_read_lock();
 565                 mpath = mesh_path_lookup(sdata, orig_addr);
 566                 if (mpath) {
 567                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 568                                 reply = true;
 569                                 target_addr = sdata->vif.addr;
 570                                 target_sn = ++ifmsh->sn;
 571                                 target_metric = 0;
 572                                 ifmsh->last_sn_update = jiffies;
 573                         }
 574                         if (root_is_gate)
 575                                 mesh_path_add_gate(mpath);
 576                 }
 577                 rcu_read_unlock();
 578         } else {
 579                 rcu_read_lock();
 580                 mpath = mesh_path_lookup(sdata, target_addr);
 581                 if (mpath) {
 582                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 583                                         SN_LT(mpath->sn, target_sn)) {
 584                                 mpath->sn = target_sn;
 585                                 mpath->flags |= MESH_PATH_SN_VALID;
 586                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 587                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 588                                 reply = true;
 589                                 target_metric = mpath->metric;
 590                                 target_sn = mpath->sn;
 591                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 592                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 593                         }
 594                 }
 595                 rcu_read_unlock();
 596         }
 597
 598         if (reply) {
 599                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 600                 ttl = ifmsh->mshcfg.element_ttl;
 601                 if (ttl != 0) {
 602                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 603                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 604                                                orig_sn, 0, target_addr,
 605                                                target_sn, mgmt->sa, 0, ttl,
 606                                                lifetime, target_metric, 0,
 607                                                sdata);
 608                 } else {
 609                         ifmsh->mshstats.dropped_frames_ttl++;
 610                 }
 611         }
 612
 613         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 614                 u32 preq_id;
 615                 u8 hopcount;
 616
 617                 ttl = PREQ_IE_TTL(preq_elem);
 618                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 619                 if (ttl <= 1) {
 620                         ifmsh->mshstats.dropped_frames_ttl++;
 621                         return;
 622                 }
 623                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 624                 --ttl;
 625                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 626                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 627                 da = (mpath && mpath->is_root) ?
 628                         mpath->rann_snd_addr : broadcast_addr;
 629
 630                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 631                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 632                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 633                 }
 634
 635                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 636                                        orig_sn, target_flags, target_addr,
 637                                        target_sn, da, hopcount, ttl, lifetime,
 638                                        orig_metric, preq_id, sdata);
 639                 if (!is_multicast_ether_addr(da))
 640                         ifmsh->mshstats.fwded_unicast++;
 641                 else
 642                         ifmsh->mshstats.fwded_mcast++;
 643                 ifmsh->mshstats.fwded_frames++;
 644         }
 645 }
 646
 647
 648 static inline struct sta_info *
 649 next_hop_deref_protected(struct mesh_path *mpath)
 650 {
 651         return rcu_dereference_protected(mpath->next_hop,
 652                                          lockdep_is_held(&mpath->state_lock));
 653 }
 654
 655
 656 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 657                                     struct ieee80211_mgmt *mgmt,
 658                                     const u8 *prep_elem, u32 metric)
 659 {
 660         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 661         struct mesh_path *mpath;
 662         const u8 *target_addr, *orig_addr;
 663         u8 ttl, hopcount, flags;
 664         u8 next_hop[ETH_ALEN];
 665         u32 target_sn, orig_sn, lifetime;
 666
 667         mhwmp_dbg(sdata, "received PREP from %pM\n",
 668                   PREP_IE_TARGET_ADDR(prep_elem));
 669
 670         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 671         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 672                 /* destination, no forwarding required */
 673                 return;
 674
 675         if (!ifmsh->mshcfg.dot11MeshForwarding)
 676                 return;
 677
 678         ttl = PREP_IE_TTL(prep_elem);
 679         if (ttl <= 1) {
 680                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 681                 return;
 682         }
 683
 684         rcu_read_lock();
 685         mpath = mesh_path_lookup(sdata, orig_addr);
 686         if (mpath)
 687                 spin_lock_bh(&mpath->state_lock);
 688         else
 689                 goto fail;
 690         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 691                 spin_unlock_bh(&mpath->state_lock);
 692                 goto fail;
 693         }
 694         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 695         spin_unlock_bh(&mpath->state_lock);
 696         --ttl;
 697         flags = PREP_IE_FLAGS(prep_elem);
 698         lifetime = PREP_IE_LIFETIME(prep_elem);
 699         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 700         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 701         target_sn = PREP_IE_TARGET_SN(prep_elem);
 702         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 703
 704         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 705                                target_addr, target_sn, next_hop, hopcount,
 706                                ttl, lifetime, metric, 0, sdata);
 707         rcu_read_unlock();
 708
 709         sdata->u.mesh.mshstats.fwded_unicast++;
 710         sdata->u.mesh.mshstats.fwded_frames++;
 711         return;
 712
 713 fail:
 714         rcu_read_unlock();
 715         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 716 }
 717
 718 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 719                                     struct ieee80211_mgmt *mgmt,
 720                                     const u8 *perr_elem)
 721 {
 722         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 723         struct mesh_path *mpath;
 724         u8 ttl;
 725         const u8 *ta, *target_addr;
 726         u32 target_sn;
 727         u16 target_rcode;
 728
 729         ta = mgmt->sa;
 730         ttl = PERR_IE_TTL(perr_elem);
 731         if (ttl <= 1) {
 732                 ifmsh->mshstats.dropped_frames_ttl++;
 733                 return;
 734         }
 735         ttl--;
 736         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 737         target_sn = PERR_IE_TARGET_SN(perr_elem);
 738         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 739
 740         rcu_read_lock();
 741         mpath = mesh_path_lookup(sdata, target_addr);
 742         if (mpath) {
 743                 struct sta_info *sta;
 744
 745                 spin_lock_bh(&mpath->state_lock);
 746                 sta = next_hop_deref_protected(mpath);
 747                 if (mpath->flags & MESH_PATH_ACTIVE &&
 748                     ether_addr_equal(ta, sta->sta.addr) &&
 749                     !(mpath->flags & MESH_PATH_FIXED) &&
 750                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 751                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 752                         mpath->flags &= ~MESH_PATH_ACTIVE;
 753                         if (target_sn != 0)
 754                                 mpath->sn = target_sn;
 755                         else
 756                                 mpath->sn += 1;
 757                         spin_unlock_bh(&mpath->state_lock);
 758                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 759                                 goto endperr;
 760                         mesh_path_error_tx(sdata, ttl, target_addr,
 761                                            target_sn, target_rcode,
 762                                            broadcast_addr);
 763                 } else
 764                         spin_unlock_bh(&mpath->state_lock);
 765         }
 766 endperr:
 767         rcu_read_unlock();
 768 }
 769
 770 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 771                                     struct ieee80211_mgmt *mgmt,
 772                                     const struct ieee80211_rann_ie *rann)
 773 {
 774         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 775         struct ieee80211_local *local = sdata->local;
 776         struct sta_info *sta;
 777         struct mesh_path *mpath;
 778         u8 ttl, flags, hopcount;
 779         const u8 *orig_addr;
 780         u32 orig_sn, metric, metric_txsta, interval;
 781         bool root_is_gate;
 782
 783         ttl = rann->rann_ttl;
 784         flags = rann->rann_flags;
 785         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 786         orig_addr = rann->rann_addr;
 787         orig_sn = le32_to_cpu(rann->rann_seq);
 788         interval = le32_to_cpu(rann->rann_interval);
 789         hopcount = rann->rann_hopcount;
 790         hopcount++;
 791         metric = le32_to_cpu(rann->rann_metric);
 792
 793         /*  Ignore our own RANNs */
 794         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 795                 return;
 796
 797         mhwmp_dbg(sdata,
 798                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 799                   orig_addr, mgmt->sa, root_is_gate);
 800
 801         rcu_read_lock();
 802         sta = sta_info_get(sdata, mgmt->sa);
 803         if (!sta) {
 804                 rcu_read_unlock();
 805                 return;
 806         }
 807
 808         metric_txsta = airtime_link_metric_get(local, sta);
 809
 810         mpath = mesh_path_lookup(sdata, orig_addr);
 811         if (!mpath) {
 812                 mpath = mesh_path_add(sdata, orig_addr);
 813                 if (IS_ERR(mpath)) {
 814                         rcu_read_unlock();
 815                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 816                         return;
 817                 }
 818         }
 819
 820         if (!(SN_LT(mpath->sn, orig_sn)) &&
 821             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 822                 rcu_read_unlock();
 823                 return;
 824         }
 825
 826         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 827              (time_after(jiffies, mpath->last_preq_to_root +
 828                                   root_path_confirmation_jiffies(sdata)) ||
 829              time_before(jiffies, mpath->last_preq_to_root))) &&
 830              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 831                 mhwmp_dbg(sdata,
 832                           "time to refresh root mpath %pM\n",
 833                           orig_addr);
 834                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 835                 mpath->last_preq_to_root = jiffies;
 836         }
 837
 838         mpath->sn = orig_sn;
 839         mpath->rann_metric = metric + metric_txsta;
 840         mpath->is_root = true;
 841         /* Recording RANNs sender address to send individually
 842          * addressed PREQs destined for root mesh STA */
 843         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 844
 845         if (root_is_gate)
 846                 mesh_path_add_gate(mpath);
 847
 848         if (ttl <= 1) {
 849                 ifmsh->mshstats.dropped_frames_ttl++;
 850                 rcu_read_unlock();
 851                 return;
 852         }
 853         ttl--;
 854
 855         if (ifmsh->mshcfg.dot11MeshForwarding) {
 856                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 857                                        orig_sn, 0, NULL, 0, broadcast_addr,
 858                                        hopcount, ttl, interval,
 859                                        metric + metric_txsta, 0, sdata);
 860         }
 861
 862         rcu_read_unlock();
 863 }
 864
 865
 866 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 867                             struct ieee80211_mgmt *mgmt, size_t len)
 868 {
 869         struct ieee802_11_elems elems;
 870         size_t baselen;
 871         u32 path_metric;
 872         struct sta_info *sta;
 873
 874         /* need action_code */
 875         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 876                 return;
 877
 878         rcu_read_lock();
 879         sta = sta_info_get(sdata, mgmt->sa);
 880         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 881                 rcu_read_unlock();
 882                 return;
 883         }
 884         rcu_read_unlock();
 885
 886         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 887         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 888                                len - baselen, false, &elems);
 889
 890         if (elems.preq) {
 891                 if (elems.preq_len != 37)
 892                         /* Right now we support just 1 destination and no AE */
 893                         return;
 894                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 895                                                   MPATH_PREQ);
 896                 if (path_metric)
 897                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 898                                                 path_metric);
 899         }
 900         if (elems.prep) {
 901                 if (elems.prep_len != 31)
 902                         /* Right now we support no AE */
 903                         return;
 904                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 905                                                   MPATH_PREP);
 906                 if (path_metric)
 907                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 908                                                 path_metric);
 909         }
 910         if (elems.perr) {
 911                 if (elems.perr_len != 15)
 912                         /* Right now we support only one destination per PERR */
 913                         return;
 914                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 915         }
 916         if (elems.rann)
 917                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 918 }
 919
 920 /**
 921  * mesh_queue_preq - queue a PREQ to a given destination
 922  *
 923  * @mpath: mesh path to discover
 924  * @flags: special attributes of the PREQ to be sent
 925  *
 926  * Locking: the function must be called from within a rcu read lock block.
 927  *
 928  */
 929 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 930 {
 931         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 932         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 933         struct mesh_preq_queue *preq_node;
 934
 935         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 936         if (!preq_node) {
 937                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 938                 return;
 939         }
 940
 941         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 942         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 943                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 944                 kfree(preq_node);
 945                 if (printk_ratelimit())
 946                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 947                 return;
 948         }
 949
 950         spin_lock(&mpath->state_lock);
 951         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 952                 spin_unlock(&mpath->state_lock);
 953                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 954                 kfree(preq_node);
 955                 return;
 956         }
 957
 958         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 959         preq_node->flags = flags;
 960
 961         mpath->flags |= MESH_PATH_REQ_QUEUED;
 962         spin_unlock(&mpath->state_lock);
 963
 964         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 965         ++ifmsh->preq_queue_len;
 966         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 967
 968         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 969                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 970
 971         else if (time_before(jiffies, ifmsh->last_preq)) {
 972                 /* avoid long wait if did not send preqs for a long time
 973                  * and jiffies wrapped around
 974                  */
 975                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 976                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 977         } else
 978                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 979                                                 min_preq_int_jiff(sdata));
 980 }
 981
 982 /**
 983  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 984  *
 985  * @sdata: local mesh subif
 986  */
 987 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 988 {
 989         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 990         struct mesh_preq_queue *preq_node;
 991         struct mesh_path *mpath;
 992         u8 ttl, target_flags = 0;
 993         const u8 *da;
 994         u32 lifetime;
 995
 996         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 997         if (!ifmsh->preq_queue_len ||
 998                 time_before(jiffies, ifmsh->last_preq +
 999                                 min_preq_int_jiff(sdata))) {
1000                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1001                 return;
1002         }
1003
1004         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1005                         struct mesh_preq_queue, list);
1006         list_del(&preq_node->list);
1007         --ifmsh->preq_queue_len;
1008         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1009
1010         rcu_read_lock();
1011         mpath = mesh_path_lookup(sdata, preq_node->dst);
1012         if (!mpath)
1013                 goto enddiscovery;
1014
1015         spin_lock_bh(&mpath->state_lock);
1016         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1017                 spin_unlock_bh(&mpath->state_lock);
1018                 goto enddiscovery;
1019         }
1020         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1021         if (preq_node->flags & PREQ_Q_F_START) {
1022                 if (mpath->flags & MESH_PATH_RESOLVING) {
1023                         spin_unlock_bh(&mpath->state_lock);
1024                         goto enddiscovery;
1025                 } else {
1026                         mpath->flags &= ~MESH_PATH_RESOLVED;
1027                         mpath->flags |= MESH_PATH_RESOLVING;
1028                         mpath->discovery_retries = 0;
1029                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1030                 }
1031         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1032                         mpath->flags & MESH_PATH_RESOLVED) {
1033                 mpath->flags &= ~MESH_PATH_RESOLVING;
1034                 spin_unlock_bh(&mpath->state_lock);
1035                 goto enddiscovery;
1036         }
1037
1038         ifmsh->last_preq = jiffies;
1039
1040         if (time_after(jiffies, ifmsh->last_sn_update +
1041                                 net_traversal_jiffies(sdata)) ||
1042             time_before(jiffies, ifmsh->last_sn_update)) {
1043                 ++ifmsh->sn;
1044                 sdata->u.mesh.last_sn_update = jiffies;
1045         }
1046         lifetime = default_lifetime(sdata);
1047         ttl = sdata->u.mesh.mshcfg.element_ttl;
1048         if (ttl == 0) {
1049                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1050                 spin_unlock_bh(&mpath->state_lock);
1051                 goto enddiscovery;
1052         }
1053
1054         if (preq_node->flags & PREQ_Q_F_REFRESH)
1055                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1056         else
1057                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1058
1059         spin_unlock_bh(&mpath->state_lock);
1060         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1061         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1062                                target_flags, mpath->dst, mpath->sn, da, 0,
1063                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1064         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1065
1066 enddiscovery:
1067         rcu_read_unlock();
1068         kfree(preq_node);
1069 }
1070
1071 /**
1072  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1073  *
1074  * @skb: 802.11 frame to be sent
1075  * @sdata: network subif the frame will be sent through
1076  *
1077  * Lookup next hop for given skb and start path discovery if no
1078  * forwarding information is found.
1079  *
1080  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1081  * skb is freeed here if no mpath could be allocated.
1082  */
1083 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1084                          struct sk_buff *skb)
1085 {
1086         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1087         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1088         struct mesh_path *mpath;
1089         struct sk_buff *skb_to_free = NULL;
1090         u8 *target_addr = hdr->addr3;
1091         int err = 0;
1092
1093         /* Nulls are only sent to peers for PS and should be pre-addressed */
1094         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1095                 return 0;
1096
1097         rcu_read_lock();
1098         err = mesh_nexthop_lookup(sdata, skb);
1099         if (!err)
1100                 goto endlookup;
1101
1102         /* no nexthop found, start resolving */
1103         mpath = mesh_path_lookup(sdata, target_addr);
1104         if (!mpath) {
1105                 mpath = mesh_path_add(sdata, target_addr);
1106                 if (IS_ERR(mpath)) {
1107                         mesh_path_discard_frame(sdata, skb);
1108                         err = PTR_ERR(mpath);
1109                         goto endlookup;
1110                 }
1111         }
1112
1113         if (!(mpath->flags & MESH_PATH_RESOLVING))
1114                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1115
1116         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1117                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1118
1119         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1120         ieee80211_set_qos_hdr(sdata, skb);
1121         skb_queue_tail(&mpath->frame_queue, skb);
1122         err = -ENOENT;
1123         if (skb_to_free)
1124                 mesh_path_discard_frame(sdata, skb_to_free);
1125
1126 endlookup:
1127         rcu_read_unlock();
1128         return err;
1129 }
1130
1131 /**
1132  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1133  * this function is considered "using" the associated mpath, so preempt a path
1134  * refresh if this mpath expires soon.
1135  *
1136  * @skb: 802.11 frame to be sent
1137  * @sdata: network subif the frame will be sent through
1138  *
1139  * Returns: 0 if the next hop was found. Nonzero otherwise.
1140  */
1141 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1142                         struct sk_buff *skb)
1143 {
1144         struct mesh_path *mpath;
1145         struct sta_info *next_hop;
1146         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1147         u8 *target_addr = hdr->addr3;
1148         int err = -ENOENT;
1149
1150         rcu_read_lock();
1151         mpath = mesh_path_lookup(sdata, target_addr);
1152
1153         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1154                 goto endlookup;
1155
1156         if (time_after(jiffies,
1157                        mpath->exp_time -
1158                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1159             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1160             !(mpath->flags & MESH_PATH_RESOLVING) &&
1161             !(mpath->flags & MESH_PATH_FIXED))
1162                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1163
1164         next_hop = rcu_dereference(mpath->next_hop);
1165         if (next_hop) {
1166                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1167                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1168                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1169                 err = 0;
1170         }
1171
1172 endlookup:
1173         rcu_read_unlock();
1174         return err;
1175 }
1176
1177 void mesh_path_timer(unsigned long data)
1178 {
1179         struct mesh_path *mpath = (void *) data;
1180         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1181         int ret;
1182
1183         if (sdata->local->quiescing)
1184                 return;
1185
1186         spin_lock_bh(&mpath->state_lock);
1187         if (mpath->flags & MESH_PATH_RESOLVED ||
1188                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1189                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1190                 spin_unlock_bh(&mpath->state_lock);
1191         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1192                 ++mpath->discovery_retries;
1193                 mpath->discovery_timeout *= 2;
1194                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1195                 spin_unlock_bh(&mpath->state_lock);
1196                 mesh_queue_preq(mpath, 0);
1197         } else {
1198                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1199                                   MESH_PATH_RESOLVED |
1200                                   MESH_PATH_REQ_QUEUED);
1201                 mpath->exp_time = jiffies;
1202                 spin_unlock_bh(&mpath->state_lock);
1203                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1204                         ret = mesh_path_send_to_gates(mpath);
1205                         if (ret)
1206                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1207                 } else
1208                         mesh_path_flush_pending(mpath);
1209         }
1210 }
1211
1212 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1213 {
1214         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1215         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1216         u8 flags, target_flags = 0;
1217
1218         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1219                         ? RANN_FLAG_IS_GATE : 0;
1220
1221         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1222         case IEEE80211_PROACTIVE_RANN:
1223                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1224                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1225                                        0, ifmsh->mshcfg.element_ttl,
1226                                        interval, 0, 0, sdata);
1227                 break;
1228         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1229                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1230         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1231                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1232                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1233                                 IEEE80211_PREQ_USN_FLAG;
1234                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1235                                        ++ifmsh->sn, target_flags,
1236                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1237                                        0, ifmsh->mshcfg.element_ttl, interval,
1238                                        0, ifmsh->preq_id++, sdata);
1239                 break;
1240         default:
1241                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1242                 return;
1243         }
1244 }