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->plink_state != NL80211_PLINK_ESTAB)
 330                 return MAX_METRIC;
 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 (sta->mesh->fail_avg >= 100)
 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 = (sta->mesh->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 = ((u64)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                         mesh_path_tx_pending(mpath);
 491                         /* draft says preq_id should be saved to, but there does
 492                          * not seem to be any use for it, skipping by now
 493                          */
 494                 } else
 495                         spin_unlock_bh(&mpath->state_lock);
 496         }
 497
 498         /* Update and check transmitter routing info */
 499         ta = mgmt->sa;
 500         if (ether_addr_equal(orig_addr, ta))
 501                 fresh_info = false;
 502         else {
 503                 fresh_info = true;
 504
 505                 mpath = mesh_path_lookup(sdata, ta);
 506                 if (mpath) {
 507                         spin_lock_bh(&mpath->state_lock);
 508                         if ((mpath->flags & MESH_PATH_FIXED) ||
 509                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 510                                         (last_hop_metric > mpath->metric)))
 511                                 fresh_info = false;
 512                 } else {
 513                         mpath = mesh_path_add(sdata, ta);
 514                         if (IS_ERR(mpath)) {
 515                                 rcu_read_unlock();
 516                                 return 0;
 517                         }
 518                         spin_lock_bh(&mpath->state_lock);
 519                 }
 520
 521                 if (fresh_info) {
 522                         mesh_path_assign_nexthop(mpath, sta);
 523                         mpath->metric = last_hop_metric;
 524                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 525                                           ?  mpath->exp_time : exp_time;
 526                         mesh_path_activate(mpath);
 527                         spin_unlock_bh(&mpath->state_lock);
 528                         mesh_path_tx_pending(mpath);
 529                 } else
 530                         spin_unlock_bh(&mpath->state_lock);
 531         }
 532
 533         rcu_read_unlock();
 534
 535         return process ? new_metric : 0;
 536 }
 537
 538 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 539                                     struct ieee80211_mgmt *mgmt,
 540                                     const u8 *preq_elem, u32 orig_metric)
 541 {
 542         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 543         struct mesh_path *mpath = NULL;
 544         const u8 *target_addr, *orig_addr;
 545         const u8 *da;
 546         u8 target_flags, ttl, flags;
 547         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 548         bool reply = false;
 549         bool forward = true;
 550         bool root_is_gate;
 551
 552         /* Update target SN, if present */
 553         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 554         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 555         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 556         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 557         target_flags = PREQ_IE_TARGET_F(preq_elem);
 558         /* Proactive PREQ gate announcements */
 559         flags = PREQ_IE_FLAGS(preq_elem);
 560         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 561
 562         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 563
 564         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 565                 mhwmp_dbg(sdata, "PREQ is for us\n");
 566                 forward = false;
 567                 reply = true;
 568                 target_metric = 0;
 569
 570                 if (SN_GT(target_sn, ifmsh->sn))
 571                         ifmsh->sn = target_sn;
 572
 573                 if (time_after(jiffies, ifmsh->last_sn_update +
 574                                         net_traversal_jiffies(sdata)) ||
 575                     time_before(jiffies, ifmsh->last_sn_update)) {
 576                         ++ifmsh->sn;
 577                         ifmsh->last_sn_update = jiffies;
 578                 }
 579                 target_sn = ifmsh->sn;
 580         } else if (is_broadcast_ether_addr(target_addr) &&
 581                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 582                 rcu_read_lock();
 583                 mpath = mesh_path_lookup(sdata, orig_addr);
 584                 if (mpath) {
 585                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 586                                 reply = true;
 587                                 target_addr = sdata->vif.addr;
 588                                 target_sn = ++ifmsh->sn;
 589                                 target_metric = 0;
 590                                 ifmsh->last_sn_update = jiffies;
 591                         }
 592                         if (root_is_gate)
 593                                 mesh_path_add_gate(mpath);
 594                 }
 595                 rcu_read_unlock();
 596         } else {
 597                 rcu_read_lock();
 598                 mpath = mesh_path_lookup(sdata, target_addr);
 599                 if (mpath) {
 600                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 601                                         SN_LT(mpath->sn, target_sn)) {
 602                                 mpath->sn = target_sn;
 603                                 mpath->flags |= MESH_PATH_SN_VALID;
 604                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 605                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 606                                 reply = true;
 607                                 target_metric = mpath->metric;
 608                                 target_sn = mpath->sn;
 609                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 610                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 611                         }
 612                 }
 613                 rcu_read_unlock();
 614         }
 615
 616         if (reply) {
 617                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 618                 ttl = ifmsh->mshcfg.element_ttl;
 619                 if (ttl != 0) {
 620                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 621                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 622                                                orig_sn, 0, target_addr,
 623                                                target_sn, mgmt->sa, 0, ttl,
 624                                                lifetime, target_metric, 0,
 625                                                sdata);
 626                 } else {
 627                         ifmsh->mshstats.dropped_frames_ttl++;
 628                 }
 629         }
 630
 631         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 632                 u32 preq_id;
 633                 u8 hopcount;
 634
 635                 ttl = PREQ_IE_TTL(preq_elem);
 636                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 637                 if (ttl <= 1) {
 638                         ifmsh->mshstats.dropped_frames_ttl++;
 639                         return;
 640                 }
 641                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 642                 --ttl;
 643                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 644                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 645                 da = (mpath && mpath->is_root) ?
 646                         mpath->rann_snd_addr : broadcast_addr;
 647
 648                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 649                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 650                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 651                 }
 652
 653                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 654                                        orig_sn, target_flags, target_addr,
 655                                        target_sn, da, hopcount, ttl, lifetime,
 656                                        orig_metric, preq_id, sdata);
 657                 if (!is_multicast_ether_addr(da))
 658                         ifmsh->mshstats.fwded_unicast++;
 659                 else
 660                         ifmsh->mshstats.fwded_mcast++;
 661                 ifmsh->mshstats.fwded_frames++;
 662         }
 663 }
 664
 665
 666 static inline struct sta_info *
 667 next_hop_deref_protected(struct mesh_path *mpath)
 668 {
 669         return rcu_dereference_protected(mpath->next_hop,
 670                                          lockdep_is_held(&mpath->state_lock));
 671 }
 672
 673
 674 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 675                                     struct ieee80211_mgmt *mgmt,
 676                                     const u8 *prep_elem, u32 metric)
 677 {
 678         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 679         struct mesh_path *mpath;
 680         const u8 *target_addr, *orig_addr;
 681         u8 ttl, hopcount, flags;
 682         u8 next_hop[ETH_ALEN];
 683         u32 target_sn, orig_sn, lifetime;
 684
 685         mhwmp_dbg(sdata, "received PREP from %pM\n",
 686                   PREP_IE_TARGET_ADDR(prep_elem));
 687
 688         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 689         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 690                 /* destination, no forwarding required */
 691                 return;
 692
 693         if (!ifmsh->mshcfg.dot11MeshForwarding)
 694                 return;
 695
 696         ttl = PREP_IE_TTL(prep_elem);
 697         if (ttl <= 1) {
 698                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 699                 return;
 700         }
 701
 702         rcu_read_lock();
 703         mpath = mesh_path_lookup(sdata, orig_addr);
 704         if (mpath)
 705                 spin_lock_bh(&mpath->state_lock);
 706         else
 707                 goto fail;
 708         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 709                 spin_unlock_bh(&mpath->state_lock);
 710                 goto fail;
 711         }
 712         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 713         spin_unlock_bh(&mpath->state_lock);
 714         --ttl;
 715         flags = PREP_IE_FLAGS(prep_elem);
 716         lifetime = PREP_IE_LIFETIME(prep_elem);
 717         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 718         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 719         target_sn = PREP_IE_TARGET_SN(prep_elem);
 720         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 721
 722         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 723                                target_addr, target_sn, next_hop, hopcount,
 724                                ttl, lifetime, metric, 0, sdata);
 725         rcu_read_unlock();
 726
 727         sdata->u.mesh.mshstats.fwded_unicast++;
 728         sdata->u.mesh.mshstats.fwded_frames++;
 729         return;
 730
 731 fail:
 732         rcu_read_unlock();
 733         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 734 }
 735
 736 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 737                                     struct ieee80211_mgmt *mgmt,
 738                                     const u8 *perr_elem)
 739 {
 740         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 741         struct mesh_path *mpath;
 742         u8 ttl;
 743         const u8 *ta, *target_addr;
 744         u32 target_sn;
 745         u16 target_rcode;
 746
 747         ta = mgmt->sa;
 748         ttl = PERR_IE_TTL(perr_elem);
 749         if (ttl <= 1) {
 750                 ifmsh->mshstats.dropped_frames_ttl++;
 751                 return;
 752         }
 753         ttl--;
 754         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 755         target_sn = PERR_IE_TARGET_SN(perr_elem);
 756         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 757
 758         rcu_read_lock();
 759         mpath = mesh_path_lookup(sdata, target_addr);
 760         if (mpath) {
 761                 struct sta_info *sta;
 762
 763                 spin_lock_bh(&mpath->state_lock);
 764                 sta = next_hop_deref_protected(mpath);
 765                 if (mpath->flags & MESH_PATH_ACTIVE &&
 766                     ether_addr_equal(ta, sta->sta.addr) &&
 767                     !(mpath->flags & MESH_PATH_FIXED) &&
 768                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 769                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 770                         mpath->flags &= ~MESH_PATH_ACTIVE;
 771                         if (target_sn != 0)
 772                                 mpath->sn = target_sn;
 773                         else
 774                                 mpath->sn += 1;
 775                         spin_unlock_bh(&mpath->state_lock);
 776                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 777                                 goto endperr;
 778                         mesh_path_error_tx(sdata, ttl, target_addr,
 779                                            target_sn, target_rcode,
 780                                            broadcast_addr);
 781                 } else
 782                         spin_unlock_bh(&mpath->state_lock);
 783         }
 784 endperr:
 785         rcu_read_unlock();
 786 }
 787
 788 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 789                                     struct ieee80211_mgmt *mgmt,
 790                                     const struct ieee80211_rann_ie *rann)
 791 {
 792         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 793         struct ieee80211_local *local = sdata->local;
 794         struct sta_info *sta;
 795         struct mesh_path *mpath;
 796         u8 ttl, flags, hopcount;
 797         const u8 *orig_addr;
 798         u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
 799         bool root_is_gate;
 800
 801         ttl = rann->rann_ttl;
 802         flags = rann->rann_flags;
 803         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 804         orig_addr = rann->rann_addr;
 805         orig_sn = le32_to_cpu(rann->rann_seq);
 806         interval = le32_to_cpu(rann->rann_interval);
 807         hopcount = rann->rann_hopcount;
 808         hopcount++;
 809         orig_metric = le32_to_cpu(rann->rann_metric);
 810
 811         /*  Ignore our own RANNs */
 812         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 813                 return;
 814
 815         mhwmp_dbg(sdata,
 816                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 817                   orig_addr, mgmt->sa, root_is_gate);
 818
 819         rcu_read_lock();
 820         sta = sta_info_get(sdata, mgmt->sa);
 821         if (!sta) {
 822                 rcu_read_unlock();
 823                 return;
 824         }
 825
 826         last_hop_metric = airtime_link_metric_get(local, sta);
 827         new_metric = orig_metric + last_hop_metric;
 828         if (new_metric < orig_metric)
 829                 new_metric = MAX_METRIC;
 830
 831         mpath = mesh_path_lookup(sdata, orig_addr);
 832         if (!mpath) {
 833                 mpath = mesh_path_add(sdata, orig_addr);
 834                 if (IS_ERR(mpath)) {
 835                         rcu_read_unlock();
 836                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 837                         return;
 838                 }
 839         }
 840
 841         if (!(SN_LT(mpath->sn, orig_sn)) &&
 842             !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
 843                 rcu_read_unlock();
 844                 return;
 845         }
 846
 847         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 848              (time_after(jiffies, mpath->last_preq_to_root +
 849                                   root_path_confirmation_jiffies(sdata)) ||
 850              time_before(jiffies, mpath->last_preq_to_root))) &&
 851              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 852                 mhwmp_dbg(sdata,
 853                           "time to refresh root mpath %pM\n",
 854                           orig_addr);
 855                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 856                 mpath->last_preq_to_root = jiffies;
 857         }
 858
 859         mpath->sn = orig_sn;
 860         mpath->rann_metric = new_metric;
 861         mpath->is_root = true;
 862         /* Recording RANNs sender address to send individually
 863          * addressed PREQs destined for root mesh STA */
 864         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 865
 866         if (root_is_gate)
 867                 mesh_path_add_gate(mpath);
 868
 869         if (ttl <= 1) {
 870                 ifmsh->mshstats.dropped_frames_ttl++;
 871                 rcu_read_unlock();
 872                 return;
 873         }
 874         ttl--;
 875
 876         if (ifmsh->mshcfg.dot11MeshForwarding) {
 877                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 878                                        orig_sn, 0, NULL, 0, broadcast_addr,
 879                                        hopcount, ttl, interval,
 880                                        new_metric, 0, sdata);
 881         }
 882
 883         rcu_read_unlock();
 884 }
 885
 886
 887 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 888                             struct ieee80211_mgmt *mgmt, size_t len)
 889 {
 890         struct ieee802_11_elems elems;
 891         size_t baselen;
 892         u32 path_metric;
 893         struct sta_info *sta;
 894
 895         /* need action_code */
 896         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 897                 return;
 898
 899         rcu_read_lock();
 900         sta = sta_info_get(sdata, mgmt->sa);
 901         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 902                 rcu_read_unlock();
 903                 return;
 904         }
 905         rcu_read_unlock();
 906
 907         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 908         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 909                                len - baselen, false, &elems);
 910
 911         if (elems.preq) {
 912                 if (elems.preq_len != 37)
 913                         /* Right now we support just 1 destination and no AE */
 914                         return;
 915                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 916                                                   MPATH_PREQ);
 917                 if (path_metric)
 918                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 919                                                 path_metric);
 920         }
 921         if (elems.prep) {
 922                 if (elems.prep_len != 31)
 923                         /* Right now we support no AE */
 924                         return;
 925                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 926                                                   MPATH_PREP);
 927                 if (path_metric)
 928                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 929                                                 path_metric);
 930         }
 931         if (elems.perr) {
 932                 if (elems.perr_len != 15)
 933                         /* Right now we support only one destination per PERR */
 934                         return;
 935                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 936         }
 937         if (elems.rann)
 938                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 939 }
 940
 941 /**
 942  * mesh_queue_preq - queue a PREQ to a given destination
 943  *
 944  * @mpath: mesh path to discover
 945  * @flags: special attributes of the PREQ to be sent
 946  *
 947  * Locking: the function must be called from within a rcu read lock block.
 948  *
 949  */
 950 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 951 {
 952         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 953         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 954         struct mesh_preq_queue *preq_node;
 955
 956         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 957         if (!preq_node) {
 958                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 959                 return;
 960         }
 961
 962         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 963         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 964                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 965                 kfree(preq_node);
 966                 if (printk_ratelimit())
 967                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 968                 return;
 969         }
 970
 971         spin_lock(&mpath->state_lock);
 972         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 973                 spin_unlock(&mpath->state_lock);
 974                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 975                 kfree(preq_node);
 976                 return;
 977         }
 978
 979         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 980         preq_node->flags = flags;
 981
 982         mpath->flags |= MESH_PATH_REQ_QUEUED;
 983         spin_unlock(&mpath->state_lock);
 984
 985         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 986         ++ifmsh->preq_queue_len;
 987         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 988
 989         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 990                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 991
 992         else if (time_before(jiffies, ifmsh->last_preq)) {
 993                 /* avoid long wait if did not send preqs for a long time
 994                  * and jiffies wrapped around
 995                  */
 996                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 997                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 998         } else
 999                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1000                                                 min_preq_int_jiff(sdata));
1001 }
1002
1003 /**
1004  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1005  *
1006  * @sdata: local mesh subif
1007  */
1008 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1009 {
1010         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1011         struct mesh_preq_queue *preq_node;
1012         struct mesh_path *mpath;
1013         u8 ttl, target_flags = 0;
1014         const u8 *da;
1015         u32 lifetime;
1016
1017         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1018         if (!ifmsh->preq_queue_len ||
1019                 time_before(jiffies, ifmsh->last_preq +
1020                                 min_preq_int_jiff(sdata))) {
1021                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1022                 return;
1023         }
1024
1025         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1026                         struct mesh_preq_queue, list);
1027         list_del(&preq_node->list);
1028         --ifmsh->preq_queue_len;
1029         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1030
1031         rcu_read_lock();
1032         mpath = mesh_path_lookup(sdata, preq_node->dst);
1033         if (!mpath)
1034                 goto enddiscovery;
1035
1036         spin_lock_bh(&mpath->state_lock);
1037         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1038                 spin_unlock_bh(&mpath->state_lock);
1039                 goto enddiscovery;
1040         }
1041         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1042         if (preq_node->flags & PREQ_Q_F_START) {
1043                 if (mpath->flags & MESH_PATH_RESOLVING) {
1044                         spin_unlock_bh(&mpath->state_lock);
1045                         goto enddiscovery;
1046                 } else {
1047                         mpath->flags &= ~MESH_PATH_RESOLVED;
1048                         mpath->flags |= MESH_PATH_RESOLVING;
1049                         mpath->discovery_retries = 0;
1050                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1051                 }
1052         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1053                         mpath->flags & MESH_PATH_RESOLVED) {
1054                 mpath->flags &= ~MESH_PATH_RESOLVING;
1055                 spin_unlock_bh(&mpath->state_lock);
1056                 goto enddiscovery;
1057         }
1058
1059         ifmsh->last_preq = jiffies;
1060
1061         if (time_after(jiffies, ifmsh->last_sn_update +
1062                                 net_traversal_jiffies(sdata)) ||
1063             time_before(jiffies, ifmsh->last_sn_update)) {
1064                 ++ifmsh->sn;
1065                 sdata->u.mesh.last_sn_update = jiffies;
1066         }
1067         lifetime = default_lifetime(sdata);
1068         ttl = sdata->u.mesh.mshcfg.element_ttl;
1069         if (ttl == 0) {
1070                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1071                 spin_unlock_bh(&mpath->state_lock);
1072                 goto enddiscovery;
1073         }
1074
1075         if (preq_node->flags & PREQ_Q_F_REFRESH)
1076                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1077         else
1078                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1079
1080         spin_unlock_bh(&mpath->state_lock);
1081         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1082         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1083                                target_flags, mpath->dst, mpath->sn, da, 0,
1084                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1085
1086         spin_lock_bh(&mpath->state_lock);
1087         if (mpath->flags & MESH_PATH_DELETED) {
1088                 spin_unlock_bh(&mpath->state_lock);
1089                 goto enddiscovery;
1090         }
1091         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1092         spin_unlock_bh(&mpath->state_lock);
1093
1094 enddiscovery:
1095         rcu_read_unlock();
1096         kfree(preq_node);
1097 }
1098
1099 /**
1100  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1101  *
1102  * @skb: 802.11 frame to be sent
1103  * @sdata: network subif the frame will be sent through
1104  *
1105  * Lookup next hop for given skb and start path discovery if no
1106  * forwarding information is found.
1107  *
1108  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1109  * skb is freeed here if no mpath could be allocated.
1110  */
1111 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1112                          struct sk_buff *skb)
1113 {
1114         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1115         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1116         struct mesh_path *mpath;
1117         struct sk_buff *skb_to_free = NULL;
1118         u8 *target_addr = hdr->addr3;
1119         int err = 0;
1120
1121         /* Nulls are only sent to peers for PS and should be pre-addressed */
1122         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1123                 return 0;
1124
1125         rcu_read_lock();
1126         err = mesh_nexthop_lookup(sdata, skb);
1127         if (!err)
1128                 goto endlookup;
1129
1130         /* no nexthop found, start resolving */
1131         mpath = mesh_path_lookup(sdata, target_addr);
1132         if (!mpath) {
1133                 mpath = mesh_path_add(sdata, target_addr);
1134                 if (IS_ERR(mpath)) {
1135                         mesh_path_discard_frame(sdata, skb);
1136                         err = PTR_ERR(mpath);
1137                         goto endlookup;
1138                 }
1139         }
1140
1141         if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1142             mesh_path_sel_is_hwmp(sdata))
1143                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1144
1145         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1146                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1147
1148         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1149         ieee80211_set_qos_hdr(sdata, skb);
1150         skb_queue_tail(&mpath->frame_queue, skb);
1151         err = -ENOENT;
1152         if (skb_to_free)
1153                 mesh_path_discard_frame(sdata, skb_to_free);
1154
1155 endlookup:
1156         rcu_read_unlock();
1157         return err;
1158 }
1159
1160 /**
1161  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1162  * this function is considered "using" the associated mpath, so preempt a path
1163  * refresh if this mpath expires soon.
1164  *
1165  * @skb: 802.11 frame to be sent
1166  * @sdata: network subif the frame will be sent through
1167  *
1168  * Returns: 0 if the next hop was found. Nonzero otherwise.
1169  */
1170 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1171                         struct sk_buff *skb)
1172 {
1173         struct mesh_path *mpath;
1174         struct sta_info *next_hop;
1175         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1176         u8 *target_addr = hdr->addr3;
1177         int err = -ENOENT;
1178
1179         rcu_read_lock();
1180         mpath = mesh_path_lookup(sdata, target_addr);
1181
1182         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1183                 goto endlookup;
1184
1185         if (time_after(jiffies,
1186                        mpath->exp_time -
1187                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1188             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1189             !(mpath->flags & MESH_PATH_RESOLVING) &&
1190             !(mpath->flags & MESH_PATH_FIXED))
1191                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1192
1193         next_hop = rcu_dereference(mpath->next_hop);
1194         if (next_hop) {
1195                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1196                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1197                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1198                 err = 0;
1199         }
1200
1201 endlookup:
1202         rcu_read_unlock();
1203         return err;
1204 }
1205
1206 void mesh_path_timer(unsigned long data)
1207 {
1208         struct mesh_path *mpath = (void *) data;
1209         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1210         int ret;
1211
1212         if (sdata->local->quiescing)
1213                 return;
1214
1215         spin_lock_bh(&mpath->state_lock);
1216         if (mpath->flags & MESH_PATH_RESOLVED ||
1217                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1218                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1219                 spin_unlock_bh(&mpath->state_lock);
1220         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1221                 ++mpath->discovery_retries;
1222                 mpath->discovery_timeout *= 2;
1223                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1224                 spin_unlock_bh(&mpath->state_lock);
1225                 mesh_queue_preq(mpath, 0);
1226         } else {
1227                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1228                                   MESH_PATH_RESOLVED |
1229                                   MESH_PATH_REQ_QUEUED);
1230                 mpath->exp_time = jiffies;
1231                 spin_unlock_bh(&mpath->state_lock);
1232                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1233                         ret = mesh_path_send_to_gates(mpath);
1234                         if (ret)
1235                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1236                 } else
1237                         mesh_path_flush_pending(mpath);
1238         }
1239 }
1240
1241 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1242 {
1243         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1244         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1245         u8 flags, target_flags = 0;
1246
1247         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1248                         ? RANN_FLAG_IS_GATE : 0;
1249
1250         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1251         case IEEE80211_PROACTIVE_RANN:
1252                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1253                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1254                                        0, ifmsh->mshcfg.element_ttl,
1255                                        interval, 0, 0, sdata);
1256                 break;
1257         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1258                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1259         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1260                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1261                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1262                                 IEEE80211_PREQ_USN_FLAG;
1263                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1264                                        ++ifmsh->sn, target_flags,
1265                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1266                                        0, ifmsh->mshcfg.element_ttl, interval,
1267                                        0, ifmsh->preq_id++, sdata);
1268                 break;
1269         default:
1270                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1271                 return;
1272         }
1273 }