net/mac80211/mesh_hwmp.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/etherdevice.h>
  12 #include <asm/unaligned.h>
  13 #include "wme.h"
  14 #include "mesh.h"
  15
  16 #define TEST_FRAME_LEN  8192
  17 #define MAX_METRIC      0xffffffff
  18 #define ARITH_SHIFT     8
  19 #define LINK_FAIL_THRESH 95
  20
  21 #define MAX_PREQ_QUEUE_LEN      64
  22
  23 static void mesh_queue_preq(struct mesh_path *, u8);
  24
  25 static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
  26 {
  27         if (ae)
  28                 offset += 6;
  29         return get_unaligned_le32(preq_elem + offset);
  30 }
  31
  32 static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
  33 {
  34         if (ae)
  35                 offset += 6;
  36         return get_unaligned_le16(preq_elem + offset);
  37 }
  38
  39 /* HWMP IE processing macros */
  40 #define AE_F                    (1<<6)
  41 #define AE_F_SET(x)             (*x & AE_F)
  42 #define PREQ_IE_FLAGS(x)        (*(x))
  43 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  44 #define PREQ_IE_TTL(x)          (*(x + 2))
  45 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  46 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  47 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  48 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  49 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  50 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  51 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  52 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  53
  54
  55 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  56 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  57 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  58 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  59 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  60 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  61 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  62 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  63 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  64
  65 #define PERR_IE_TTL(x)          (*(x))
  66 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  67 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  68 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  69 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  70
  71 #define MSEC_TO_TU(x) (x*1000/1024)
  72 #define SN_GT(x, y) ((s32)(y - x) < 0)
  73 #define SN_LT(x, y) ((s32)(x - y) < 0)
  74 #define MAX_SANE_SN_DELTA 32
  75
  76 static inline u32 SN_DELTA(u32 x, u32 y)
  77 {
  78         return x >= y ? x - y : y - x;
  79 }
  80
  81 #define net_traversal_jiffies(s) \
  82         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  83 #define default_lifetime(s) \
  84         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  85 #define min_preq_int_jiff(s) \
  86         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  87 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  88 #define disc_timeout_jiff(s) \
  89         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  90 #define root_path_confirmation_jiffies(s) \
  91         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  92
  93 enum mpath_frame_type {
  94         MPATH_PREQ = 0,
  95         MPATH_PREP,
  96         MPATH_PERR,
  97         MPATH_RANN
  98 };
  99
 100 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 101
 102 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 103                                   const u8 *orig_addr, u32 orig_sn,
 104                                   u8 target_flags, const u8 *target,
 105                                   u32 target_sn, const u8 *da,
 106                                   u8 hop_count, u8 ttl,
 107                                   u32 lifetime, u32 metric, u32 preq_id,
 108                                   struct ieee80211_sub_if_data *sdata)
 109 {
 110         struct ieee80211_local *local = sdata->local;
 111         struct sk_buff *skb;
 112         struct ieee80211_mgmt *mgmt;
 113         u8 *pos, ie_len;
 114         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 115                       sizeof(mgmt->u.action.u.mesh_action);
 116
 117         skb = dev_alloc_skb(local->tx_headroom +
 118                             hdr_len +
 119                             2 + 37); /* max HWMP IE */
 120         if (!skb)
 121                 return -1;
 122         skb_reserve(skb, local->tx_headroom);
 123         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 124         memset(mgmt, 0, hdr_len);
 125         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 126                                           IEEE80211_STYPE_ACTION);
 127
 128         memcpy(mgmt->da, da, ETH_ALEN);
 129         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 130         /* BSSID == SA */
 131         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 132         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 133         mgmt->u.action.u.mesh_action.action_code =
 134                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 135
 136         switch (action) {
 137         case MPATH_PREQ:
 138                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 139                 ie_len = 37;
 140                 pos = skb_put(skb, 2 + ie_len);
 141                 *pos++ = WLAN_EID_PREQ;
 142                 break;
 143         case MPATH_PREP:
 144                 mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
 145                 ie_len = 31;
 146                 pos = skb_put(skb, 2 + ie_len);
 147                 *pos++ = WLAN_EID_PREP;
 148                 break;
 149         case MPATH_RANN:
 150                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 151                 ie_len = sizeof(struct ieee80211_rann_ie);
 152                 pos = skb_put(skb, 2 + ie_len);
 153                 *pos++ = WLAN_EID_RANN;
 154                 break;
 155         default:
 156                 kfree_skb(skb);
 157                 return -ENOTSUPP;
 158         }
 159         *pos++ = ie_len;
 160         *pos++ = flags;
 161         *pos++ = hop_count;
 162         *pos++ = ttl;
 163         if (action == MPATH_PREP) {
 164                 memcpy(pos, target, ETH_ALEN);
 165                 pos += ETH_ALEN;
 166                 put_unaligned_le32(target_sn, pos);
 167                 pos += 4;
 168         } else {
 169                 if (action == MPATH_PREQ) {
 170                         put_unaligned_le32(preq_id, pos);
 171                         pos += 4;
 172                 }
 173                 memcpy(pos, orig_addr, ETH_ALEN);
 174                 pos += ETH_ALEN;
 175                 put_unaligned_le32(orig_sn, pos);
 176                 pos += 4;
 177         }
 178         put_unaligned_le32(lifetime, pos); /* interval for RANN */
 179         pos += 4;
 180         put_unaligned_le32(metric, pos);
 181         pos += 4;
 182         if (action == MPATH_PREQ) {
 183                 *pos++ = 1; /* destination count */
 184                 *pos++ = target_flags;
 185                 memcpy(pos, target, ETH_ALEN);
 186                 pos += ETH_ALEN;
 187                 put_unaligned_le32(target_sn, pos);
 188                 pos += 4;
 189         } else if (action == MPATH_PREP) {
 190                 memcpy(pos, orig_addr, ETH_ALEN);
 191                 pos += ETH_ALEN;
 192                 put_unaligned_le32(orig_sn, pos);
 193                 pos += 4;
 194         }
 195
 196         ieee80211_tx_skb(sdata, skb);
 197         return 0;
 198 }
 199
 200
 201 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 202  *  headroom in case the frame is encrypted. */
 203 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 204                 struct sk_buff *skb)
 205 {
 206         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 207         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 208
 209         skb_reset_mac_header(skb);
 210         skb_reset_network_header(skb);
 211         skb_reset_transport_header(skb);
 212
 213         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 214         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 215         skb->priority = 7;
 216
 217         info->control.vif = &sdata->vif;
 218         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 219         ieee80211_set_qos_hdr(sdata, skb);
 220         ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
 221 }
 222
 223 /**
 224  * mesh_path_error_tx - Sends a PERR mesh management frame
 225  *
 226  * @ttl: allowed remaining hops
 227  * @target: broken destination
 228  * @target_sn: SN of the broken destination
 229  * @target_rcode: reason code for this PERR
 230  * @ra: node this frame is addressed to
 231  * @sdata: local mesh subif
 232  *
 233  * Note: This function may be called with driver locks taken that the driver
 234  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 235  * frame directly but add it to the pending queue instead.
 236  */
 237 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 238                        u8 ttl, const u8 *target, u32 target_sn,
 239                        u16 target_rcode, const u8 *ra)
 240 {
 241         struct ieee80211_local *local = sdata->local;
 242         struct sk_buff *skb;
 243         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 244         struct ieee80211_mgmt *mgmt;
 245         u8 *pos, ie_len;
 246         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 247                       sizeof(mgmt->u.action.u.mesh_action);
 248
 249         if (time_before(jiffies, ifmsh->next_perr))
 250                 return -EAGAIN;
 251
 252         skb = dev_alloc_skb(local->tx_headroom +
 253                             sdata->encrypt_headroom +
 254                             IEEE80211_ENCRYPT_TAILROOM +
 255                             hdr_len +
 256                             2 + 15 /* PERR IE */);
 257         if (!skb)
 258                 return -1;
 259         skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom);
 260         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 261         memset(mgmt, 0, hdr_len);
 262         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 263                                           IEEE80211_STYPE_ACTION);
 264
 265         memcpy(mgmt->da, ra, ETH_ALEN);
 266         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 267         /* BSSID == SA */
 268         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 269         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 270         mgmt->u.action.u.mesh_action.action_code =
 271                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 272         ie_len = 15;
 273         pos = skb_put(skb, 2 + ie_len);
 274         *pos++ = WLAN_EID_PERR;
 275         *pos++ = ie_len;
 276         /* ttl */
 277         *pos++ = ttl;
 278         /* number of destinations */
 279         *pos++ = 1;
 280         /* Flags field has AE bit only as defined in
 281          * sec 8.4.2.117 IEEE802.11-2012
 282          */
 283         *pos = 0;
 284         pos++;
 285         memcpy(pos, target, ETH_ALEN);
 286         pos += ETH_ALEN;
 287         put_unaligned_le32(target_sn, pos);
 288         pos += 4;
 289         put_unaligned_le16(target_rcode, pos);
 290
 291         /* see note in function header */
 292         prepare_frame_for_deferred_tx(sdata, skb);
 293         ifmsh->next_perr = TU_TO_EXP_TIME(
 294                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 295         ieee80211_add_pending_skb(local, skb);
 296         return 0;
 297 }
 298
 299 void ieee80211s_update_metric(struct ieee80211_local *local,
 300                 struct sta_info *sta, struct sk_buff *skb)
 301 {
 302         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 303         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 304         int failed;
 305
 306         if (!ieee80211_is_data(hdr->frame_control))
 307                 return;
 308
 309         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 310
 311         /* moving average, scaled to 100.
 312          * feed failure as 100 and success as 0
 313          */
 314         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
 315         if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
 316                         LINK_FAIL_THRESH)
 317                 mesh_plink_broken(sta);
 318 }
 319
 320 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 321                                    struct sta_info *sta)
 322 {
 323         struct rate_info rinfo;
 324         /* This should be adjusted for each device */
 325         int device_constant = 1 << ARITH_SHIFT;
 326         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 327         int s_unit = 1 << ARITH_SHIFT;
 328         int rate, err;
 329         u32 tx_time, estimated_retx;
 330         u64 result;
 331         unsigned long fail_avg =
 332                 ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
 333
 334         /* Try to get rate based on HW/SW RC algorithm.
 335          * Rate is returned in units of Kbps, correct this
 336          * to comply with airtime calculation units
 337          * Round up in case we get rate < 100Kbps
 338          */
 339         rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
 340
 341         if (rate) {
 342                 err = 0;
 343         } else {
 344                 if (fail_avg > LINK_FAIL_THRESH)
 345                         return MAX_METRIC;
 346
 347                 sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
 348                 rate = cfg80211_calculate_bitrate(&rinfo);
 349                 if (WARN_ON(!rate))
 350                         return MAX_METRIC;
 351
 352                 err = (fail_avg << ARITH_SHIFT) / 100;
 353         }
 354
 355         /* bitrate is in units of 100 Kbps, while we need rate in units of
 356          * 1Mbps. This will be corrected on tx_time computation.
 357          */
 358         tx_time = (device_constant + 10 * test_frame_len / rate);
 359         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 360         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
 361         return (u32)result;
 362 }
 363
 364 /**
 365  * hwmp_route_info_get - Update routing info to originator and transmitter
 366  *
 367  * @sdata: local mesh subif
 368  * @mgmt: mesh management frame
 369  * @hwmp_ie: hwmp information element (PREP or PREQ)
 370  * @action: type of hwmp ie
 371  *
 372  * This function updates the path routing information to the originator and the
 373  * transmitter of a HWMP PREQ or PREP frame.
 374  *
 375  * Returns: metric to frame originator or 0 if the frame should not be further
 376  * processed
 377  *
 378  * Notes: this function is the only place (besides user-provided info) where
 379  * path routing information is updated.
 380  */
 381 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 382                                struct ieee80211_mgmt *mgmt,
 383                                const u8 *hwmp_ie, enum mpath_frame_type action)
 384 {
 385         struct ieee80211_local *local = sdata->local;
 386         struct mesh_path *mpath;
 387         struct sta_info *sta;
 388         bool fresh_info;
 389         const u8 *orig_addr, *ta;
 390         u32 orig_sn, orig_metric;
 391         unsigned long orig_lifetime, exp_time;
 392         u32 last_hop_metric, new_metric;
 393         bool process = true;
 394
 395         rcu_read_lock();
 396         sta = sta_info_get(sdata, mgmt->sa);
 397         if (!sta) {
 398                 rcu_read_unlock();
 399                 return 0;
 400         }
 401
 402         last_hop_metric = airtime_link_metric_get(local, sta);
 403         /* Update and check originator routing info */
 404         fresh_info = true;
 405
 406         switch (action) {
 407         case MPATH_PREQ:
 408                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 409                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 410                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 411                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 412                 break;
 413         case MPATH_PREP:
 414                 /* Originator here refers to the MP that was the target in the
 415                  * Path Request. We divert from the nomenclature in the draft
 416                  * so that we can easily use a single function to gather path
 417                  * information from both PREQ and PREP frames.
 418                  */
 419                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 420                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 421                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 422                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 423                 break;
 424         default:
 425                 rcu_read_unlock();
 426                 return 0;
 427         }
 428         new_metric = orig_metric + last_hop_metric;
 429         if (new_metric < orig_metric)
 430                 new_metric = MAX_METRIC;
 431         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 432
 433         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 434                 /* This MP is the originator, we are not interested in this
 435                  * frame, except for updating transmitter's path info.
 436                  */
 437                 process = false;
 438                 fresh_info = false;
 439         } else {
 440                 mpath = mesh_path_lookup(sdata, orig_addr);
 441                 if (mpath) {
 442                         spin_lock_bh(&mpath->state_lock);
 443                         if (mpath->flags & MESH_PATH_FIXED)
 444                                 fresh_info = false;
 445                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 446                             (mpath->flags & MESH_PATH_SN_VALID)) {
 447                                 if (SN_GT(mpath->sn, orig_sn) ||
 448                                     (mpath->sn == orig_sn &&
 449                                      new_metric >= mpath->metric)) {
 450                                         process = false;
 451                                         fresh_info = false;
 452                                 }
 453                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 454                                 bool have_sn, newer_sn, bounced;
 455
 456                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 457                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 458                                 bounced = have_sn &&
 459                                           (SN_DELTA(orig_sn, mpath->sn) >
 460                                                         MAX_SANE_SN_DELTA);
 461
 462                                 if (!have_sn || newer_sn) {
 463                                         /* if SN is newer than what we had
 464                                          * then we can take it */;
 465                                 } else if (bounced) {
 466                                         /* if SN is way different than what
 467                                          * we had then assume the other side
 468                                          * rebooted or restarted */;
 469                                 } else {
 470                                         process = false;
 471                                         fresh_info = false;
 472                                 }
 473                         }
 474                 } else {
 475                         mpath = mesh_path_add(sdata, orig_addr);
 476                         if (IS_ERR(mpath)) {
 477                                 rcu_read_unlock();
 478                                 return 0;
 479                         }
 480                         spin_lock_bh(&mpath->state_lock);
 481                 }
 482
 483                 if (fresh_info) {
 484                         mesh_path_assign_nexthop(mpath, sta);
 485                         mpath->flags |= MESH_PATH_SN_VALID;
 486                         mpath->metric = new_metric;
 487                         mpath->sn = orig_sn;
 488                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 489                                           ?  mpath->exp_time : exp_time;
 490                         mesh_path_activate(mpath);
 491                         spin_unlock_bh(&mpath->state_lock);
 492                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 493                         /* init it at a low value - 0 start is tricky */
 494                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 495                         mesh_path_tx_pending(mpath);
 496                         /* draft says preq_id should be saved to, but there does
 497                          * not seem to be any use for it, skipping by now
 498                          */
 499                 } else
 500                         spin_unlock_bh(&mpath->state_lock);
 501         }
 502
 503         /* Update and check transmitter routing info */
 504         ta = mgmt->sa;
 505         if (ether_addr_equal(orig_addr, ta))
 506                 fresh_info = false;
 507         else {
 508                 fresh_info = true;
 509
 510                 mpath = mesh_path_lookup(sdata, ta);
 511                 if (mpath) {
 512                         spin_lock_bh(&mpath->state_lock);
 513                         if ((mpath->flags & MESH_PATH_FIXED) ||
 514                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 515                                         (last_hop_metric > mpath->metric)))
 516                                 fresh_info = false;
 517                 } else {
 518                         mpath = mesh_path_add(sdata, ta);
 519                         if (IS_ERR(mpath)) {
 520                                 rcu_read_unlock();
 521                                 return 0;
 522                         }
 523                         spin_lock_bh(&mpath->state_lock);
 524                 }
 525
 526                 if (fresh_info) {
 527                         mesh_path_assign_nexthop(mpath, sta);
 528                         mpath->metric = last_hop_metric;
 529                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 530                                           ?  mpath->exp_time : exp_time;
 531                         mesh_path_activate(mpath);
 532                         spin_unlock_bh(&mpath->state_lock);
 533                         ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 534                         /* init it at a low value - 0 start is tricky */
 535                         ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 536                         mesh_path_tx_pending(mpath);
 537                 } else
 538                         spin_unlock_bh(&mpath->state_lock);
 539         }
 540
 541         rcu_read_unlock();
 542
 543         return process ? new_metric : 0;
 544 }
 545
 546 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 547                                     struct ieee80211_mgmt *mgmt,
 548                                     const u8 *preq_elem, u32 orig_metric)
 549 {
 550         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 551         struct mesh_path *mpath = NULL;
 552         const u8 *target_addr, *orig_addr;
 553         const u8 *da;
 554         u8 target_flags, ttl, flags;
 555         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 556         bool reply = false;
 557         bool forward = true;
 558         bool root_is_gate;
 559
 560         /* Update target SN, if present */
 561         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 562         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 563         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 564         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 565         target_flags = PREQ_IE_TARGET_F(preq_elem);
 566         /* Proactive PREQ gate announcements */
 567         flags = PREQ_IE_FLAGS(preq_elem);
 568         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 569
 570         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 571
 572         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 573                 mhwmp_dbg(sdata, "PREQ is for us\n");
 574                 forward = false;
 575                 reply = true;
 576                 target_metric = 0;
 577                 if (time_after(jiffies, ifmsh->last_sn_update +
 578                                         net_traversal_jiffies(sdata)) ||
 579                     time_before(jiffies, ifmsh->last_sn_update)) {
 580                         ++ifmsh->sn;
 581                         ifmsh->last_sn_update = jiffies;
 582                 }
 583                 target_sn = ifmsh->sn;
 584         } else if (is_broadcast_ether_addr(target_addr) &&
 585                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 586                 rcu_read_lock();
 587                 mpath = mesh_path_lookup(sdata, orig_addr);
 588                 if (mpath) {
 589                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 590                                 reply = true;
 591                                 target_addr = sdata->vif.addr;
 592                                 target_sn = ++ifmsh->sn;
 593                                 target_metric = 0;
 594                                 ifmsh->last_sn_update = jiffies;
 595                         }
 596                         if (root_is_gate)
 597                                 mesh_path_add_gate(mpath);
 598                 }
 599                 rcu_read_unlock();
 600         } else {
 601                 rcu_read_lock();
 602                 mpath = mesh_path_lookup(sdata, target_addr);
 603                 if (mpath) {
 604                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 605                                         SN_LT(mpath->sn, target_sn)) {
 606                                 mpath->sn = target_sn;
 607                                 mpath->flags |= MESH_PATH_SN_VALID;
 608                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 609                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 610                                 reply = true;
 611                                 target_metric = mpath->metric;
 612                                 target_sn = mpath->sn;
 613                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 614                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 615                         }
 616                 }
 617                 rcu_read_unlock();
 618         }
 619
 620         if (reply) {
 621                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 622                 ttl = ifmsh->mshcfg.element_ttl;
 623                 if (ttl != 0) {
 624                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 625                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 626                                                orig_sn, 0, target_addr,
 627                                                target_sn, mgmt->sa, 0, ttl,
 628                                                lifetime, target_metric, 0,
 629                                                sdata);
 630                 } else {
 631                         ifmsh->mshstats.dropped_frames_ttl++;
 632                 }
 633         }
 634
 635         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 636                 u32 preq_id;
 637                 u8 hopcount;
 638
 639                 ttl = PREQ_IE_TTL(preq_elem);
 640                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 641                 if (ttl <= 1) {
 642                         ifmsh->mshstats.dropped_frames_ttl++;
 643                         return;
 644                 }
 645                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 646                 --ttl;
 647                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 648                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 649                 da = (mpath && mpath->is_root) ?
 650                         mpath->rann_snd_addr : broadcast_addr;
 651
 652                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 653                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 654                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 655                 }
 656
 657                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 658                                        orig_sn, target_flags, target_addr,
 659                                        target_sn, da, hopcount, ttl, lifetime,
 660                                        orig_metric, preq_id, sdata);
 661                 if (!is_multicast_ether_addr(da))
 662                         ifmsh->mshstats.fwded_unicast++;
 663                 else
 664                         ifmsh->mshstats.fwded_mcast++;
 665                 ifmsh->mshstats.fwded_frames++;
 666         }
 667 }
 668
 669
 670 static inline struct sta_info *
 671 next_hop_deref_protected(struct mesh_path *mpath)
 672 {
 673         return rcu_dereference_protected(mpath->next_hop,
 674                                          lockdep_is_held(&mpath->state_lock));
 675 }
 676
 677
 678 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 679                                     struct ieee80211_mgmt *mgmt,
 680                                     const u8 *prep_elem, u32 metric)
 681 {
 682         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 683         struct mesh_path *mpath;
 684         const u8 *target_addr, *orig_addr;
 685         u8 ttl, hopcount, flags;
 686         u8 next_hop[ETH_ALEN];
 687         u32 target_sn, orig_sn, lifetime;
 688
 689         mhwmp_dbg(sdata, "received PREP from %pM\n",
 690                   PREP_IE_TARGET_ADDR(prep_elem));
 691
 692         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 693         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 694                 /* destination, no forwarding required */
 695                 return;
 696
 697         if (!ifmsh->mshcfg.dot11MeshForwarding)
 698                 return;
 699
 700         ttl = PREP_IE_TTL(prep_elem);
 701         if (ttl <= 1) {
 702                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 703                 return;
 704         }
 705
 706         rcu_read_lock();
 707         mpath = mesh_path_lookup(sdata, orig_addr);
 708         if (mpath)
 709                 spin_lock_bh(&mpath->state_lock);
 710         else
 711                 goto fail;
 712         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 713                 spin_unlock_bh(&mpath->state_lock);
 714                 goto fail;
 715         }
 716         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 717         spin_unlock_bh(&mpath->state_lock);
 718         --ttl;
 719         flags = PREP_IE_FLAGS(prep_elem);
 720         lifetime = PREP_IE_LIFETIME(prep_elem);
 721         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 722         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 723         target_sn = PREP_IE_TARGET_SN(prep_elem);
 724         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 725
 726         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 727                                target_addr, target_sn, next_hop, hopcount,
 728                                ttl, lifetime, metric, 0, sdata);
 729         rcu_read_unlock();
 730
 731         sdata->u.mesh.mshstats.fwded_unicast++;
 732         sdata->u.mesh.mshstats.fwded_frames++;
 733         return;
 734
 735 fail:
 736         rcu_read_unlock();
 737         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 738 }
 739
 740 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 741                                     struct ieee80211_mgmt *mgmt,
 742                                     const u8 *perr_elem)
 743 {
 744         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 745         struct mesh_path *mpath;
 746         u8 ttl;
 747         const u8 *ta, *target_addr;
 748         u32 target_sn;
 749         u16 target_rcode;
 750
 751         ta = mgmt->sa;
 752         ttl = PERR_IE_TTL(perr_elem);
 753         if (ttl <= 1) {
 754                 ifmsh->mshstats.dropped_frames_ttl++;
 755                 return;
 756         }
 757         ttl--;
 758         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 759         target_sn = PERR_IE_TARGET_SN(perr_elem);
 760         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 761
 762         rcu_read_lock();
 763         mpath = mesh_path_lookup(sdata, target_addr);
 764         if (mpath) {
 765                 struct sta_info *sta;
 766
 767                 spin_lock_bh(&mpath->state_lock);
 768                 sta = next_hop_deref_protected(mpath);
 769                 if (mpath->flags & MESH_PATH_ACTIVE &&
 770                     ether_addr_equal(ta, sta->sta.addr) &&
 771                     !(mpath->flags & MESH_PATH_FIXED) &&
 772                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 773                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 774                         mpath->flags &= ~MESH_PATH_ACTIVE;
 775                         if (target_sn != 0)
 776                                 mpath->sn = target_sn;
 777                         else
 778                                 mpath->sn += 1;
 779                         spin_unlock_bh(&mpath->state_lock);
 780                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 781                                 goto endperr;
 782                         mesh_path_error_tx(sdata, ttl, target_addr,
 783                                            target_sn, target_rcode,
 784                                            broadcast_addr);
 785                 } else
 786                         spin_unlock_bh(&mpath->state_lock);
 787         }
 788 endperr:
 789         rcu_read_unlock();
 790 }
 791
 792 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 793                                     struct ieee80211_mgmt *mgmt,
 794                                     const struct ieee80211_rann_ie *rann)
 795 {
 796         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 797         struct ieee80211_local *local = sdata->local;
 798         struct sta_info *sta;
 799         struct mesh_path *mpath;
 800         u8 ttl, flags, hopcount;
 801         const u8 *orig_addr;
 802         u32 orig_sn, metric, metric_txsta, interval;
 803         bool root_is_gate;
 804
 805         ttl = rann->rann_ttl;
 806         flags = rann->rann_flags;
 807         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 808         orig_addr = rann->rann_addr;
 809         orig_sn = le32_to_cpu(rann->rann_seq);
 810         interval = le32_to_cpu(rann->rann_interval);
 811         hopcount = rann->rann_hopcount;
 812         hopcount++;
 813         metric = le32_to_cpu(rann->rann_metric);
 814
 815         /*  Ignore our own RANNs */
 816         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 817                 return;
 818
 819         mhwmp_dbg(sdata,
 820                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 821                   orig_addr, mgmt->sa, root_is_gate);
 822
 823         rcu_read_lock();
 824         sta = sta_info_get(sdata, mgmt->sa);
 825         if (!sta) {
 826                 rcu_read_unlock();
 827                 return;
 828         }
 829
 830         metric_txsta = airtime_link_metric_get(local, sta);
 831
 832         mpath = mesh_path_lookup(sdata, orig_addr);
 833         if (!mpath) {
 834                 mpath = mesh_path_add(sdata, orig_addr);
 835                 if (IS_ERR(mpath)) {
 836                         rcu_read_unlock();
 837                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 838                         return;
 839                 }
 840         }
 841
 842         if (!(SN_LT(mpath->sn, orig_sn)) &&
 843             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 844                 rcu_read_unlock();
 845                 return;
 846         }
 847
 848         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 849              (time_after(jiffies, mpath->last_preq_to_root +
 850                                   root_path_confirmation_jiffies(sdata)) ||
 851              time_before(jiffies, mpath->last_preq_to_root))) &&
 852              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 853                 mhwmp_dbg(sdata,
 854                           "time to refresh root mpath %pM\n",
 855                           orig_addr);
 856                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 857                 mpath->last_preq_to_root = jiffies;
 858         }
 859
 860         mpath->sn = orig_sn;
 861         mpath->rann_metric = metric + metric_txsta;
 862         mpath->is_root = true;
 863         /* Recording RANNs sender address to send individually
 864          * addressed PREQs destined for root mesh STA */
 865         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 866
 867         if (root_is_gate)
 868                 mesh_path_add_gate(mpath);
 869
 870         if (ttl <= 1) {
 871                 ifmsh->mshstats.dropped_frames_ttl++;
 872                 rcu_read_unlock();
 873                 return;
 874         }
 875         ttl--;
 876
 877         if (ifmsh->mshcfg.dot11MeshForwarding) {
 878                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 879                                        orig_sn, 0, NULL, 0, broadcast_addr,
 880                                        hopcount, ttl, interval,
 881                                        metric + metric_txsta, 0, sdata);
 882         }
 883
 884         rcu_read_unlock();
 885 }
 886
 887
 888 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 889                             struct ieee80211_mgmt *mgmt, size_t len)
 890 {
 891         struct ieee802_11_elems elems;
 892         size_t baselen;
 893         u32 path_metric;
 894         struct sta_info *sta;
 895
 896         /* need action_code */
 897         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 898                 return;
 899
 900         rcu_read_lock();
 901         sta = sta_info_get(sdata, mgmt->sa);
 902         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 903                 rcu_read_unlock();
 904                 return;
 905         }
 906         rcu_read_unlock();
 907
 908         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 909         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 910                                len - baselen, false, &elems);
 911
 912         if (elems.preq) {
 913                 if (elems.preq_len != 37)
 914                         /* Right now we support just 1 destination and no AE */
 915                         return;
 916                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 917                                                   MPATH_PREQ);
 918                 if (path_metric)
 919                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 920                                                 path_metric);
 921         }
 922         if (elems.prep) {
 923                 if (elems.prep_len != 31)
 924                         /* Right now we support no AE */
 925                         return;
 926                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 927                                                   MPATH_PREP);
 928                 if (path_metric)
 929                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 930                                                 path_metric);
 931         }
 932         if (elems.perr) {
 933                 if (elems.perr_len != 15)
 934                         /* Right now we support only one destination per PERR */
 935                         return;
 936                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 937         }
 938         if (elems.rann)
 939                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 940 }
 941
 942 /**
 943  * mesh_queue_preq - queue a PREQ to a given destination
 944  *
 945  * @mpath: mesh path to discover
 946  * @flags: special attributes of the PREQ to be sent
 947  *
 948  * Locking: the function must be called from within a rcu read lock block.
 949  *
 950  */
 951 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 952 {
 953         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 954         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 955         struct mesh_preq_queue *preq_node;
 956
 957         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 958         if (!preq_node) {
 959                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 960                 return;
 961         }
 962
 963         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 964         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 965                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 966                 kfree(preq_node);
 967                 if (printk_ratelimit())
 968                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 969                 return;
 970         }
 971
 972         spin_lock(&mpath->state_lock);
 973         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 974                 spin_unlock(&mpath->state_lock);
 975                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 976                 kfree(preq_node);
 977                 return;
 978         }
 979
 980         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 981         preq_node->flags = flags;
 982
 983         mpath->flags |= MESH_PATH_REQ_QUEUED;
 984         spin_unlock(&mpath->state_lock);
 985
 986         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 987         ++ifmsh->preq_queue_len;
 988         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 989
 990         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 991                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 992
 993         else if (time_before(jiffies, ifmsh->last_preq)) {
 994                 /* avoid long wait if did not send preqs for a long time
 995                  * and jiffies wrapped around
 996                  */
 997                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 998                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 999         } else
1000                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1001                                                 min_preq_int_jiff(sdata));
1002 }
1003
1004 /**
1005  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1006  *
1007  * @sdata: local mesh subif
1008  */
1009 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1010 {
1011         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1012         struct mesh_preq_queue *preq_node;
1013         struct mesh_path *mpath;
1014         u8 ttl, target_flags = 0;
1015         const u8 *da;
1016         u32 lifetime;
1017
1018         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1019         if (!ifmsh->preq_queue_len ||
1020                 time_before(jiffies, ifmsh->last_preq +
1021                                 min_preq_int_jiff(sdata))) {
1022                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1023                 return;
1024         }
1025
1026         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1027                         struct mesh_preq_queue, list);
1028         list_del(&preq_node->list);
1029         --ifmsh->preq_queue_len;
1030         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1031
1032         rcu_read_lock();
1033         mpath = mesh_path_lookup(sdata, preq_node->dst);
1034         if (!mpath)
1035                 goto enddiscovery;
1036
1037         spin_lock_bh(&mpath->state_lock);
1038         if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1039                 spin_unlock_bh(&mpath->state_lock);
1040                 goto enddiscovery;
1041         }
1042         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1043         if (preq_node->flags & PREQ_Q_F_START) {
1044                 if (mpath->flags & MESH_PATH_RESOLVING) {
1045                         spin_unlock_bh(&mpath->state_lock);
1046                         goto enddiscovery;
1047                 } else {
1048                         mpath->flags &= ~MESH_PATH_RESOLVED;
1049                         mpath->flags |= MESH_PATH_RESOLVING;
1050                         mpath->discovery_retries = 0;
1051                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1052                 }
1053         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1054                         mpath->flags & MESH_PATH_RESOLVED) {
1055                 mpath->flags &= ~MESH_PATH_RESOLVING;
1056                 spin_unlock_bh(&mpath->state_lock);
1057                 goto enddiscovery;
1058         }
1059
1060         ifmsh->last_preq = jiffies;
1061
1062         if (time_after(jiffies, ifmsh->last_sn_update +
1063                                 net_traversal_jiffies(sdata)) ||
1064             time_before(jiffies, ifmsh->last_sn_update)) {
1065                 ++ifmsh->sn;
1066                 sdata->u.mesh.last_sn_update = jiffies;
1067         }
1068         lifetime = default_lifetime(sdata);
1069         ttl = sdata->u.mesh.mshcfg.element_ttl;
1070         if (ttl == 0) {
1071                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1072                 spin_unlock_bh(&mpath->state_lock);
1073                 goto enddiscovery;
1074         }
1075
1076         if (preq_node->flags & PREQ_Q_F_REFRESH)
1077                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1078         else
1079                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1080
1081         spin_unlock_bh(&mpath->state_lock);
1082         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1083         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1084                                target_flags, mpath->dst, mpath->sn, da, 0,
1085                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1086         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1087
1088 enddiscovery:
1089         rcu_read_unlock();
1090         kfree(preq_node);
1091 }
1092
1093 /**
1094  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1095  *
1096  * @skb: 802.11 frame to be sent
1097  * @sdata: network subif the frame will be sent through
1098  *
1099  * Lookup next hop for given skb and start path discovery if no
1100  * forwarding information is found.
1101  *
1102  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1103  * skb is freeed here if no mpath could be allocated.
1104  */
1105 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1106                          struct sk_buff *skb)
1107 {
1108         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1109         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1110         struct mesh_path *mpath;
1111         struct sk_buff *skb_to_free = NULL;
1112         u8 *target_addr = hdr->addr3;
1113         int err = 0;
1114
1115         /* Nulls are only sent to peers for PS and should be pre-addressed */
1116         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1117                 return 0;
1118
1119         rcu_read_lock();
1120         err = mesh_nexthop_lookup(sdata, skb);
1121         if (!err)
1122                 goto endlookup;
1123
1124         /* no nexthop found, start resolving */
1125         mpath = mesh_path_lookup(sdata, target_addr);
1126         if (!mpath) {
1127                 mpath = mesh_path_add(sdata, target_addr);
1128                 if (IS_ERR(mpath)) {
1129                         mesh_path_discard_frame(sdata, skb);
1130                         err = PTR_ERR(mpath);
1131                         goto endlookup;
1132                 }
1133         }
1134
1135         if (!(mpath->flags & MESH_PATH_RESOLVING))
1136                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1137
1138         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1139                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1140
1141         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1142         ieee80211_set_qos_hdr(sdata, skb);
1143         skb_queue_tail(&mpath->frame_queue, skb);
1144         err = -ENOENT;
1145         if (skb_to_free)
1146                 mesh_path_discard_frame(sdata, skb_to_free);
1147
1148 endlookup:
1149         rcu_read_unlock();
1150         return err;
1151 }
1152
1153 /**
1154  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1155  * this function is considered "using" the associated mpath, so preempt a path
1156  * refresh if this mpath expires soon.
1157  *
1158  * @skb: 802.11 frame to be sent
1159  * @sdata: network subif the frame will be sent through
1160  *
1161  * Returns: 0 if the next hop was found. Nonzero otherwise.
1162  */
1163 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1164                         struct sk_buff *skb)
1165 {
1166         struct mesh_path *mpath;
1167         struct sta_info *next_hop;
1168         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1169         u8 *target_addr = hdr->addr3;
1170         int err = -ENOENT;
1171
1172         rcu_read_lock();
1173         mpath = mesh_path_lookup(sdata, target_addr);
1174
1175         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1176                 goto endlookup;
1177
1178         if (time_after(jiffies,
1179                        mpath->exp_time -
1180                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1181             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1182             !(mpath->flags & MESH_PATH_RESOLVING) &&
1183             !(mpath->flags & MESH_PATH_FIXED))
1184                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1185
1186         next_hop = rcu_dereference(mpath->next_hop);
1187         if (next_hop) {
1188                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1189                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1190                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1191                 err = 0;
1192         }
1193
1194 endlookup:
1195         rcu_read_unlock();
1196         return err;
1197 }
1198
1199 void mesh_path_timer(unsigned long data)
1200 {
1201         struct mesh_path *mpath = (void *) data;
1202         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1203         int ret;
1204
1205         if (sdata->local->quiescing)
1206                 return;
1207
1208         spin_lock_bh(&mpath->state_lock);
1209         if (mpath->flags & MESH_PATH_RESOLVED ||
1210                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1211                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1212                 spin_unlock_bh(&mpath->state_lock);
1213         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1214                 ++mpath->discovery_retries;
1215                 mpath->discovery_timeout *= 2;
1216                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1217                 spin_unlock_bh(&mpath->state_lock);
1218                 mesh_queue_preq(mpath, 0);
1219         } else {
1220                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1221                                   MESH_PATH_RESOLVED |
1222                                   MESH_PATH_REQ_QUEUED);
1223                 mpath->exp_time = jiffies;
1224                 spin_unlock_bh(&mpath->state_lock);
1225                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1226                         ret = mesh_path_send_to_gates(mpath);
1227                         if (ret)
1228                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1229                 } else
1230                         mesh_path_flush_pending(mpath);
1231         }
1232 }
1233
1234 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1235 {
1236         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1237         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1238         u8 flags, target_flags = 0;
1239
1240         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1241                         ? RANN_FLAG_IS_GATE : 0;
1242
1243         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1244         case IEEE80211_PROACTIVE_RANN:
1245                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1246                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1247                                        0, ifmsh->mshcfg.element_ttl,
1248                                        interval, 0, 0, sdata);
1249                 break;
1250         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1251                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1252         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1253                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1254                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1255                                 IEEE80211_PREQ_USN_FLAG;
1256                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1257                                        ++ifmsh->sn, target_flags,
1258                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1259                                        0, ifmsh->mshcfg.element_ttl, interval,
1260                                        0, ifmsh->preq_id++, sdata);
1261                 break;
1262         default:
1263                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1264                 return;
1265         }
1266 }