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 #ifdef CONFIG_MAC80211_VERBOSE_MHWMP_DEBUG
  17 #define mhwmp_dbg(fmt, args...) \
  18         printk(KERN_DEBUG "Mesh HWMP (%s): " fmt "\n", sdata->name, ##args)
  19 #else
  20 #define mhwmp_dbg(fmt, args...)   do { (void)(0); } while (0)
  21 #endif
  22
  23 #define TEST_FRAME_LEN  8192
  24 #define MAX_METRIC      0xffffffff
  25 #define ARITH_SHIFT     8
  26
  27 /* Number of frames buffered per destination for unresolved destinations */
  28 #define MESH_FRAME_QUEUE_LEN    10
  29 #define MAX_PREQ_QUEUE_LEN      64
  30
  31 /* Destination only */
  32 #define MP_F_DO 0x1
  33 /* Reply and forward */
  34 #define MP_F_RF 0x2
  35 /* Unknown Sequence Number */
  36 #define MP_F_USN    0x01
  37 /* Reason code Present */
  38 #define MP_F_RCODE  0x02
  39
  40 static void mesh_queue_preq(struct mesh_path *, u8);
  41
  42 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
  43 {
  44         if (ae)
  45                 offset += 6;
  46         return get_unaligned_le32(preq_elem + offset);
  47 }
  48
  49 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
  50 {
  51         if (ae)
  52                 offset += 6;
  53         return get_unaligned_le16(preq_elem + offset);
  54 }
  55
  56 /* HWMP IE processing macros */
  57 #define AE_F                    (1<<6)
  58 #define AE_F_SET(x)             (*x & AE_F)
  59 #define PREQ_IE_FLAGS(x)        (*(x))
  60 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  61 #define PREQ_IE_TTL(x)          (*(x + 2))
  62 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  63 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  64 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  65 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  66 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  67 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  68 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  69 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  70
  71
  72 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  73 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  74 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  75 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  76 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  77 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  78 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  79 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  80 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  81
  82 #define PERR_IE_TTL(x)          (*(x))
  83 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  84 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  85 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  86 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  87
  88 #define MSEC_TO_TU(x) (x*1000/1024)
  89 #define SN_GT(x, y) ((s32)(y - x) < 0)
  90 #define SN_LT(x, y) ((s32)(x - y) < 0)
  91
  92 #define net_traversal_jiffies(s) \
  93         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  94 #define default_lifetime(s) \
  95         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  96 #define min_preq_int_jiff(s) \
  97         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  98 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  99 #define disc_timeout_jiff(s) \
 100         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
 101
 102 enum mpath_frame_type {
 103         MPATH_PREQ = 0,
 104         MPATH_PREP,
 105         MPATH_PERR,
 106         MPATH_RANN
 107 };
 108
 109 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 110
 111 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 112                 u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
 113                 __le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
 114                 __le32 lifetime, __le32 metric, __le32 preq_id,
 115                 struct ieee80211_sub_if_data *sdata)
 116 {
 117         struct ieee80211_local *local = sdata->local;
 118         struct sk_buff *skb;
 119         struct ieee80211_mgmt *mgmt;
 120         u8 *pos, ie_len;
 121         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 122                       sizeof(mgmt->u.action.u.mesh_action);
 123
 124         skb = dev_alloc_skb(local->tx_headroom +
 125                             hdr_len +
 126                             2 + 37); /* max HWMP IE */
 127         if (!skb)
 128                 return -1;
 129         skb_reserve(skb, local->tx_headroom);
 130         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 131         memset(mgmt, 0, hdr_len);
 132         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 133                                           IEEE80211_STYPE_ACTION);
 134
 135         memcpy(mgmt->da, da, ETH_ALEN);
 136         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 137         /* BSSID == SA */
 138         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 139         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 140         mgmt->u.action.u.mesh_action.action_code =
 141                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 142
 143         switch (action) {
 144         case MPATH_PREQ:
 145                 mhwmp_dbg("sending PREQ to %pM", target);
 146                 ie_len = 37;
 147                 pos = skb_put(skb, 2 + ie_len);
 148                 *pos++ = WLAN_EID_PREQ;
 149                 break;
 150         case MPATH_PREP:
 151                 mhwmp_dbg("sending PREP to %pM", target);
 152                 ie_len = 31;
 153                 pos = skb_put(skb, 2 + ie_len);
 154                 *pos++ = WLAN_EID_PREP;
 155                 break;
 156         case MPATH_RANN:
 157                 mhwmp_dbg("sending RANN from %pM", orig_addr);
 158                 ie_len = sizeof(struct ieee80211_rann_ie);
 159                 pos = skb_put(skb, 2 + ie_len);
 160                 *pos++ = WLAN_EID_RANN;
 161                 break;
 162         default:
 163                 kfree_skb(skb);
 164                 return -ENOTSUPP;
 165                 break;
 166         }
 167         *pos++ = ie_len;
 168         *pos++ = flags;
 169         *pos++ = hop_count;
 170         *pos++ = ttl;
 171         if (action == MPATH_PREP) {
 172                 memcpy(pos, target, ETH_ALEN);
 173                 pos += ETH_ALEN;
 174                 memcpy(pos, &target_sn, 4);
 175                 pos += 4;
 176         } else {
 177                 if (action == MPATH_PREQ) {
 178                         memcpy(pos, &preq_id, 4);
 179                         pos += 4;
 180                 }
 181                 memcpy(pos, orig_addr, ETH_ALEN);
 182                 pos += ETH_ALEN;
 183                 memcpy(pos, &orig_sn, 4);
 184                 pos += 4;
 185         }
 186         memcpy(pos, &lifetime, 4);      /* interval for RANN */
 187         pos += 4;
 188         memcpy(pos, &metric, 4);
 189         pos += 4;
 190         if (action == MPATH_PREQ) {
 191                 *pos++ = 1; /* destination count */
 192                 *pos++ = target_flags;
 193                 memcpy(pos, target, ETH_ALEN);
 194                 pos += ETH_ALEN;
 195                 memcpy(pos, &target_sn, 4);
 196                 pos += 4;
 197         } else if (action == MPATH_PREP) {
 198                 memcpy(pos, orig_addr, ETH_ALEN);
 199                 pos += ETH_ALEN;
 200                 memcpy(pos, &orig_sn, 4);
 201                 pos += 4;
 202         }
 203
 204         ieee80211_tx_skb(sdata, skb);
 205         return 0;
 206 }
 207
 208
 209 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 210  *  headroom in case the frame is encrypted. */
 211 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 212                 struct sk_buff *skb)
 213 {
 214         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 215
 216         skb_set_mac_header(skb, 0);
 217         skb_set_network_header(skb, 0);
 218         skb_set_transport_header(skb, 0);
 219
 220         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 221         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 222         skb->priority = 7;
 223
 224         info->control.vif = &sdata->vif;
 225         ieee80211_set_qos_hdr(sdata, skb);
 226 }
 227
 228 /**
 229  * mesh_send_path error - Sends a PERR mesh management frame
 230  *
 231  * @target: broken destination
 232  * @target_sn: SN of the broken destination
 233  * @target_rcode: reason code for this PERR
 234  * @ra: node this frame is addressed to
 235  *
 236  * Note: This function may be called with driver locks taken that the driver
 237  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 238  * frame directly but add it to the pending queue instead.
 239  */
 240 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 241                        __le16 target_rcode, const u8 *ra,
 242                        struct ieee80211_sub_if_data *sdata)
 243 {
 244         struct ieee80211_local *local = sdata->local;
 245         struct sk_buff *skb;
 246         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 247         struct ieee80211_mgmt *mgmt;
 248         u8 *pos, ie_len;
 249         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 250                       sizeof(mgmt->u.action.u.mesh_action);
 251
 252         if (time_before(jiffies, ifmsh->next_perr))
 253                 return -EAGAIN;
 254
 255         skb = dev_alloc_skb(local->tx_headroom +
 256                             hdr_len +
 257                             2 + 15 /* PERR IE */);
 258         if (!skb)
 259                 return -1;
 260         skb_reserve(skb, local->tx_headroom);
 261         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 262         memset(mgmt, 0, hdr_len);
 263         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 264                                           IEEE80211_STYPE_ACTION);
 265
 266         memcpy(mgmt->da, ra, ETH_ALEN);
 267         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 268         /* BSSID == SA */
 269         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 270         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 271         mgmt->u.action.u.mesh_action.action_code =
 272                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 273         ie_len = 15;
 274         pos = skb_put(skb, 2 + ie_len);
 275         *pos++ = WLAN_EID_PERR;
 276         *pos++ = ie_len;
 277         /* ttl */
 278         *pos++ = ttl;
 279         /* number of destinations */
 280         *pos++ = 1;
 281         /*
 282          * flags bit, bit 1 is unset if we know the sequence number and
 283          * bit 2 is set if we have a reason code
 284          */
 285         *pos = 0;
 286         if (!target_sn)
 287                 *pos |= MP_F_USN;
 288         if (target_rcode)
 289                 *pos |= MP_F_RCODE;
 290         pos++;
 291         memcpy(pos, target, ETH_ALEN);
 292         pos += ETH_ALEN;
 293         memcpy(pos, &target_sn, 4);
 294         pos += 4;
 295         memcpy(pos, &target_rcode, 2);
 296
 297         /* see note in function header */
 298         prepare_frame_for_deferred_tx(sdata, skb);
 299         ifmsh->next_perr = TU_TO_EXP_TIME(
 300                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 301         ieee80211_add_pending_skb(local, skb);
 302         return 0;
 303 }
 304
 305 void ieee80211s_update_metric(struct ieee80211_local *local,
 306                 struct sta_info *stainfo, struct sk_buff *skb)
 307 {
 308         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 309         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 310         int failed;
 311
 312         if (!ieee80211_is_data(hdr->frame_control))
 313                 return;
 314
 315         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 316
 317         /* moving average, scaled to 100 */
 318         stainfo->fail_avg = ((80 * stainfo->fail_avg + 5) / 100 + 20 * failed);
 319         if (stainfo->fail_avg > 95)
 320                 mesh_plink_broken(stainfo);
 321 }
 322
 323 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 324                                    struct sta_info *sta)
 325 {
 326         struct ieee80211_supported_band *sband;
 327         struct rate_info rinfo;
 328         /* This should be adjusted for each device */
 329         int device_constant = 1 << ARITH_SHIFT;
 330         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 331         int s_unit = 1 << ARITH_SHIFT;
 332         int rate, err;
 333         u32 tx_time, estimated_retx;
 334         u64 result;
 335
 336         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 337
 338         if (sta->fail_avg >= 100)
 339                 return MAX_METRIC;
 340
 341         sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
 342         rate = cfg80211_calculate_bitrate(&rinfo);
 343         if (WARN_ON(!rate))
 344                 return MAX_METRIC;
 345
 346         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 347
 348         /* bitrate is in units of 100 Kbps, while we need rate in units of
 349          * 1Mbps. This will be corrected on tx_time computation.
 350          */
 351         tx_time = (device_constant + 10 * test_frame_len / rate);
 352         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 353         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 354         return (u32)result;
 355 }
 356
 357 /**
 358  * hwmp_route_info_get - Update routing info to originator and transmitter
 359  *
 360  * @sdata: local mesh subif
 361  * @mgmt: mesh management frame
 362  * @hwmp_ie: hwmp information element (PREP or PREQ)
 363  *
 364  * This function updates the path routing information to the originator and the
 365  * transmitter of a HWMP PREQ or PREP frame.
 366  *
 367  * Returns: metric to frame originator or 0 if the frame should not be further
 368  * processed
 369  *
 370  * Notes: this function is the only place (besides user-provided info) where
 371  * path routing information is updated.
 372  */
 373 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 374                             struct ieee80211_mgmt *mgmt,
 375                             u8 *hwmp_ie, enum mpath_frame_type action)
 376 {
 377         struct ieee80211_local *local = sdata->local;
 378         struct mesh_path *mpath;
 379         struct sta_info *sta;
 380         bool fresh_info;
 381         u8 *orig_addr, *ta;
 382         u32 orig_sn, orig_metric;
 383         unsigned long orig_lifetime, exp_time;
 384         u32 last_hop_metric, new_metric;
 385         bool process = true;
 386
 387         rcu_read_lock();
 388         sta = sta_info_get(sdata, mgmt->sa);
 389         if (!sta) {
 390                 rcu_read_unlock();
 391                 return 0;
 392         }
 393
 394         last_hop_metric = airtime_link_metric_get(local, sta);
 395         /* Update and check originator routing info */
 396         fresh_info = true;
 397
 398         switch (action) {
 399         case MPATH_PREQ:
 400                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 401                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 402                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 403                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 404                 break;
 405         case MPATH_PREP:
 406                 /* Originator here refers to the MP that was the target in the
 407                  * Path Request. We divert from the nomenclature in the draft
 408                  * so that we can easily use a single function to gather path
 409                  * information from both PREQ and PREP frames.
 410                  */
 411                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 412                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 413                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 414                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 415                 break;
 416         default:
 417                 rcu_read_unlock();
 418                 return 0;
 419         }
 420         new_metric = orig_metric + last_hop_metric;
 421         if (new_metric < orig_metric)
 422                 new_metric = MAX_METRIC;
 423         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 424
 425         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 426                 /* This MP is the originator, we are not interested in this
 427                  * frame, except for updating transmitter's path info.
 428                  */
 429                 process = false;
 430                 fresh_info = false;
 431         } else {
 432                 mpath = mesh_path_lookup(orig_addr, sdata);
 433                 if (mpath) {
 434                         spin_lock_bh(&mpath->state_lock);
 435                         if (mpath->flags & MESH_PATH_FIXED)
 436                                 fresh_info = false;
 437                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 438                             (mpath->flags & MESH_PATH_SN_VALID)) {
 439                                 if (SN_GT(mpath->sn, orig_sn) ||
 440                                     (mpath->sn == orig_sn &&
 441                                      new_metric >= mpath->metric)) {
 442                                         process = false;
 443                                         fresh_info = false;
 444                                 }
 445                         }
 446                 } else {
 447                         mesh_path_add(orig_addr, sdata);
 448                         mpath = mesh_path_lookup(orig_addr, sdata);
 449                         if (!mpath) {
 450                                 rcu_read_unlock();
 451                                 return 0;
 452                         }
 453                         spin_lock_bh(&mpath->state_lock);
 454                 }
 455
 456                 if (fresh_info) {
 457                         mesh_path_assign_nexthop(mpath, sta);
 458                         mpath->flags |= MESH_PATH_SN_VALID;
 459                         mpath->metric = new_metric;
 460                         mpath->sn = orig_sn;
 461                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 462                                           ?  mpath->exp_time : exp_time;
 463                         mesh_path_activate(mpath);
 464                         spin_unlock_bh(&mpath->state_lock);
 465                         mesh_path_tx_pending(mpath);
 466                         /* draft says preq_id should be saved to, but there does
 467                          * not seem to be any use for it, skipping by now
 468                          */
 469                 } else
 470                         spin_unlock_bh(&mpath->state_lock);
 471         }
 472
 473         /* Update and check transmitter routing info */
 474         ta = mgmt->sa;
 475         if (ether_addr_equal(orig_addr, ta))
 476                 fresh_info = false;
 477         else {
 478                 fresh_info = true;
 479
 480                 mpath = mesh_path_lookup(ta, sdata);
 481                 if (mpath) {
 482                         spin_lock_bh(&mpath->state_lock);
 483                         if ((mpath->flags & MESH_PATH_FIXED) ||
 484                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 485                                         (last_hop_metric > mpath->metric)))
 486                                 fresh_info = false;
 487                 } else {
 488                         mesh_path_add(ta, sdata);
 489                         mpath = mesh_path_lookup(ta, sdata);
 490                         if (!mpath) {
 491                                 rcu_read_unlock();
 492                                 return 0;
 493                         }
 494                         spin_lock_bh(&mpath->state_lock);
 495                 }
 496
 497                 if (fresh_info) {
 498                         mesh_path_assign_nexthop(mpath, sta);
 499                         mpath->metric = last_hop_metric;
 500                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 501                                           ?  mpath->exp_time : exp_time;
 502                         mesh_path_activate(mpath);
 503                         spin_unlock_bh(&mpath->state_lock);
 504                         mesh_path_tx_pending(mpath);
 505                 } else
 506                         spin_unlock_bh(&mpath->state_lock);
 507         }
 508
 509         rcu_read_unlock();
 510
 511         return process ? new_metric : 0;
 512 }
 513
 514 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 515                                     struct ieee80211_mgmt *mgmt,
 516                                     u8 *preq_elem, u32 metric)
 517 {
 518         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 519         struct mesh_path *mpath = NULL;
 520         u8 *target_addr, *orig_addr;
 521         const u8 *da;
 522         u8 target_flags, ttl;
 523         u32 orig_sn, target_sn, lifetime;
 524         bool reply = false;
 525         bool forward = true;
 526
 527         /* Update target SN, if present */
 528         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 529         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 530         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 531         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 532         target_flags = PREQ_IE_TARGET_F(preq_elem);
 533
 534         mhwmp_dbg("received PREQ from %pM", orig_addr);
 535
 536         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 537                 mhwmp_dbg("PREQ is for us");
 538                 forward = false;
 539                 reply = true;
 540                 metric = 0;
 541                 if (time_after(jiffies, ifmsh->last_sn_update +
 542                                         net_traversal_jiffies(sdata)) ||
 543                     time_before(jiffies, ifmsh->last_sn_update)) {
 544                         target_sn = ++ifmsh->sn;
 545                         ifmsh->last_sn_update = jiffies;
 546                 }
 547         } else {
 548                 rcu_read_lock();
 549                 mpath = mesh_path_lookup(target_addr, sdata);
 550                 if (mpath) {
 551                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 552                                         SN_LT(mpath->sn, target_sn)) {
 553                                 mpath->sn = target_sn;
 554                                 mpath->flags |= MESH_PATH_SN_VALID;
 555                         } else if ((!(target_flags & MP_F_DO)) &&
 556                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 557                                 reply = true;
 558                                 metric = mpath->metric;
 559                                 target_sn = mpath->sn;
 560                                 if (target_flags & MP_F_RF)
 561                                         target_flags |= MP_F_DO;
 562                                 else
 563                                         forward = false;
 564                         }
 565                 }
 566                 rcu_read_unlock();
 567         }
 568
 569         if (reply) {
 570                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 571                 ttl = ifmsh->mshcfg.element_ttl;
 572                 if (ttl != 0) {
 573                         mhwmp_dbg("replying to the PREQ");
 574                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 575                                 cpu_to_le32(orig_sn), 0, target_addr,
 576                                 cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 577                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 578                                 0, sdata);
 579                 } else
 580                         ifmsh->mshstats.dropped_frames_ttl++;
 581         }
 582
 583         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 584                 u32 preq_id;
 585                 u8 hopcount, flags;
 586
 587                 ttl = PREQ_IE_TTL(preq_elem);
 588                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 589                 if (ttl <= 1) {
 590                         ifmsh->mshstats.dropped_frames_ttl++;
 591                         return;
 592                 }
 593                 mhwmp_dbg("forwarding the PREQ from %pM", orig_addr);
 594                 --ttl;
 595                 flags = PREQ_IE_FLAGS(preq_elem);
 596                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 597                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 598                 da = (mpath && mpath->is_root) ?
 599                         mpath->rann_snd_addr : broadcast_addr;
 600                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 601                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 602                                 cpu_to_le32(target_sn), da,
 603                                 hopcount, ttl, cpu_to_le32(lifetime),
 604                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 605                                 sdata);
 606                 if (!is_multicast_ether_addr(da))
 607                         ifmsh->mshstats.fwded_unicast++;
 608                 else
 609                         ifmsh->mshstats.fwded_mcast++;
 610                 ifmsh->mshstats.fwded_frames++;
 611         }
 612 }
 613
 614
 615 static inline struct sta_info *
 616 next_hop_deref_protected(struct mesh_path *mpath)
 617 {
 618         return rcu_dereference_protected(mpath->next_hop,
 619                                          lockdep_is_held(&mpath->state_lock));
 620 }
 621
 622
 623 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 624                                     struct ieee80211_mgmt *mgmt,
 625                                     u8 *prep_elem, u32 metric)
 626 {
 627         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 628         struct mesh_path *mpath;
 629         u8 *target_addr, *orig_addr;
 630         u8 ttl, hopcount, flags;
 631         u8 next_hop[ETH_ALEN];
 632         u32 target_sn, orig_sn, lifetime;
 633
 634         mhwmp_dbg("received PREP from %pM", PREP_IE_ORIG_ADDR(prep_elem));
 635
 636         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 637         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 638                 /* destination, no forwarding required */
 639                 return;
 640
 641         if (!ifmsh->mshcfg.dot11MeshForwarding)
 642                 return;
 643
 644         ttl = PREP_IE_TTL(prep_elem);
 645         if (ttl <= 1) {
 646                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 647                 return;
 648         }
 649
 650         rcu_read_lock();
 651         mpath = mesh_path_lookup(orig_addr, sdata);
 652         if (mpath)
 653                 spin_lock_bh(&mpath->state_lock);
 654         else
 655                 goto fail;
 656         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 657                 spin_unlock_bh(&mpath->state_lock);
 658                 goto fail;
 659         }
 660         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 661         spin_unlock_bh(&mpath->state_lock);
 662         --ttl;
 663         flags = PREP_IE_FLAGS(prep_elem);
 664         lifetime = PREP_IE_LIFETIME(prep_elem);
 665         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 666         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 667         target_sn = PREP_IE_TARGET_SN(prep_elem);
 668         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 669
 670         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 671                 cpu_to_le32(orig_sn), 0, target_addr,
 672                 cpu_to_le32(target_sn), next_hop, hopcount,
 673                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 674                 0, sdata);
 675         rcu_read_unlock();
 676
 677         sdata->u.mesh.mshstats.fwded_unicast++;
 678         sdata->u.mesh.mshstats.fwded_frames++;
 679         return;
 680
 681 fail:
 682         rcu_read_unlock();
 683         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 684 }
 685
 686 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 687                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 688 {
 689         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 690         struct mesh_path *mpath;
 691         u8 ttl;
 692         u8 *ta, *target_addr;
 693         u32 target_sn;
 694         u16 target_rcode;
 695
 696         ta = mgmt->sa;
 697         ttl = PERR_IE_TTL(perr_elem);
 698         if (ttl <= 1) {
 699                 ifmsh->mshstats.dropped_frames_ttl++;
 700                 return;
 701         }
 702         ttl--;
 703         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 704         target_sn = PERR_IE_TARGET_SN(perr_elem);
 705         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 706
 707         rcu_read_lock();
 708         mpath = mesh_path_lookup(target_addr, sdata);
 709         if (mpath) {
 710                 struct sta_info *sta;
 711
 712                 spin_lock_bh(&mpath->state_lock);
 713                 sta = next_hop_deref_protected(mpath);
 714                 if (mpath->flags & MESH_PATH_ACTIVE &&
 715                     ether_addr_equal(ta, sta->sta.addr) &&
 716                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 717                     SN_GT(target_sn, mpath->sn))) {
 718                         mpath->flags &= ~MESH_PATH_ACTIVE;
 719                         mpath->sn = target_sn;
 720                         spin_unlock_bh(&mpath->state_lock);
 721                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 722                                 goto endperr;
 723                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 724                                            cpu_to_le16(target_rcode),
 725                                            broadcast_addr, sdata);
 726                 } else
 727                         spin_unlock_bh(&mpath->state_lock);
 728         }
 729 endperr:
 730         rcu_read_unlock();
 731 }
 732
 733 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 734                                 struct ieee80211_mgmt *mgmt,
 735                                 struct ieee80211_rann_ie *rann)
 736 {
 737         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 738         struct ieee80211_local *local = sdata->local;
 739         struct sta_info *sta;
 740         struct mesh_path *mpath;
 741         u8 ttl, flags, hopcount;
 742         u8 *orig_addr;
 743         u32 orig_sn, metric, metric_txsta, interval;
 744         bool root_is_gate;
 745
 746         ttl = rann->rann_ttl;
 747         if (ttl <= 1) {
 748                 ifmsh->mshstats.dropped_frames_ttl++;
 749                 return;
 750         }
 751         ttl--;
 752         flags = rann->rann_flags;
 753         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 754         orig_addr = rann->rann_addr;
 755         orig_sn = le32_to_cpu(rann->rann_seq);
 756         interval = le32_to_cpu(rann->rann_interval);
 757         hopcount = rann->rann_hopcount;
 758         hopcount++;
 759         metric = le32_to_cpu(rann->rann_metric);
 760
 761         /*  Ignore our own RANNs */
 762         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 763                 return;
 764
 765         mhwmp_dbg("received RANN from %pM via neighbour %pM (is_gate=%d)",
 766                         orig_addr, mgmt->sa, root_is_gate);
 767
 768         rcu_read_lock();
 769         sta = sta_info_get(sdata, mgmt->sa);
 770         if (!sta) {
 771                 rcu_read_unlock();
 772                 return;
 773         }
 774
 775         metric_txsta = airtime_link_metric_get(local, sta);
 776
 777         mpath = mesh_path_lookup(orig_addr, sdata);
 778         if (!mpath) {
 779                 mesh_path_add(orig_addr, sdata);
 780                 mpath = mesh_path_lookup(orig_addr, sdata);
 781                 if (!mpath) {
 782                         rcu_read_unlock();
 783                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 784                         return;
 785                 }
 786         }
 787
 788         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 789              time_after(jiffies, mpath->exp_time - 1*HZ)) &&
 790              !(mpath->flags & MESH_PATH_FIXED)) {
 791                 mhwmp_dbg("%s time to refresh root mpath %pM", sdata->name,
 792                                                                orig_addr);
 793                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 794         }
 795
 796         if ((SN_LT(mpath->sn, orig_sn) || (mpath->sn == orig_sn &&
 797            metric < mpath->rann_metric)) && ifmsh->mshcfg.dot11MeshForwarding) {
 798                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 799                                        cpu_to_le32(orig_sn),
 800                                        0, NULL, 0, broadcast_addr,
 801                                        hopcount, ttl, cpu_to_le32(interval),
 802                                        cpu_to_le32(metric + metric_txsta),
 803                                        0, sdata);
 804                 mpath->sn = orig_sn;
 805                 mpath->rann_metric = metric + metric_txsta;
 806                 /* Recording RANNs sender address to send individually
 807                  * addressed PREQs destined for root mesh STA */
 808                 memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 809         }
 810
 811         mpath->is_root = true;
 812
 813         if (root_is_gate)
 814                 mesh_path_add_gate(mpath);
 815
 816         rcu_read_unlock();
 817 }
 818
 819
 820 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 821                             struct ieee80211_mgmt *mgmt,
 822                             size_t len)
 823 {
 824         struct ieee802_11_elems elems;
 825         size_t baselen;
 826         u32 last_hop_metric;
 827         struct sta_info *sta;
 828
 829         /* need action_code */
 830         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 831                 return;
 832
 833         rcu_read_lock();
 834         sta = sta_info_get(sdata, mgmt->sa);
 835         if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 836                 rcu_read_unlock();
 837                 return;
 838         }
 839         rcu_read_unlock();
 840
 841         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 842         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 843                         len - baselen, &elems);
 844
 845         if (elems.preq) {
 846                 if (elems.preq_len != 37)
 847                         /* Right now we support just 1 destination and no AE */
 848                         return;
 849                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 850                                                       MPATH_PREQ);
 851                 if (last_hop_metric)
 852                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 853                                                 last_hop_metric);
 854         }
 855         if (elems.prep) {
 856                 if (elems.prep_len != 31)
 857                         /* Right now we support no AE */
 858                         return;
 859                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 860                                                       MPATH_PREP);
 861                 if (last_hop_metric)
 862                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 863                                                 last_hop_metric);
 864         }
 865         if (elems.perr) {
 866                 if (elems.perr_len != 15)
 867                         /* Right now we support only one destination per PERR */
 868                         return;
 869                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 870         }
 871         if (elems.rann)
 872                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 873 }
 874
 875 /**
 876  * mesh_queue_preq - queue a PREQ to a given destination
 877  *
 878  * @mpath: mesh path to discover
 879  * @flags: special attributes of the PREQ to be sent
 880  *
 881  * Locking: the function must be called from within a rcu read lock block.
 882  *
 883  */
 884 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 885 {
 886         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 887         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 888         struct mesh_preq_queue *preq_node;
 889
 890         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 891         if (!preq_node) {
 892                 mhwmp_dbg("could not allocate PREQ node");
 893                 return;
 894         }
 895
 896         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 897         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 898                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 899                 kfree(preq_node);
 900                 if (printk_ratelimit())
 901                         mhwmp_dbg("PREQ node queue full");
 902                 return;
 903         }
 904
 905         spin_lock(&mpath->state_lock);
 906         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 907                 spin_unlock(&mpath->state_lock);
 908                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 909                 kfree(preq_node);
 910                 return;
 911         }
 912
 913         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 914         preq_node->flags = flags;
 915
 916         mpath->flags |= MESH_PATH_REQ_QUEUED;
 917         spin_unlock(&mpath->state_lock);
 918
 919         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 920         ++ifmsh->preq_queue_len;
 921         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 922
 923         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 924                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 925
 926         else if (time_before(jiffies, ifmsh->last_preq)) {
 927                 /* avoid long wait if did not send preqs for a long time
 928                  * and jiffies wrapped around
 929                  */
 930                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 931                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 932         } else
 933                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 934                                                 min_preq_int_jiff(sdata));
 935 }
 936
 937 /**
 938  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 939  *
 940  * @sdata: local mesh subif
 941  */
 942 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 943 {
 944         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 945         struct mesh_preq_queue *preq_node;
 946         struct mesh_path *mpath;
 947         u8 ttl, target_flags;
 948         const u8 *da;
 949         u32 lifetime;
 950
 951         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 952         if (!ifmsh->preq_queue_len ||
 953                 time_before(jiffies, ifmsh->last_preq +
 954                                 min_preq_int_jiff(sdata))) {
 955                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 956                 return;
 957         }
 958
 959         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 960                         struct mesh_preq_queue, list);
 961         list_del(&preq_node->list);
 962         --ifmsh->preq_queue_len;
 963         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 964
 965         rcu_read_lock();
 966         mpath = mesh_path_lookup(preq_node->dst, sdata);
 967         if (!mpath)
 968                 goto enddiscovery;
 969
 970         spin_lock_bh(&mpath->state_lock);
 971         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
 972         if (preq_node->flags & PREQ_Q_F_START) {
 973                 if (mpath->flags & MESH_PATH_RESOLVING) {
 974                         spin_unlock_bh(&mpath->state_lock);
 975                         goto enddiscovery;
 976                 } else {
 977                         mpath->flags &= ~MESH_PATH_RESOLVED;
 978                         mpath->flags |= MESH_PATH_RESOLVING;
 979                         mpath->discovery_retries = 0;
 980                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 981                 }
 982         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 983                         mpath->flags & MESH_PATH_RESOLVED) {
 984                 mpath->flags &= ~MESH_PATH_RESOLVING;
 985                 spin_unlock_bh(&mpath->state_lock);
 986                 goto enddiscovery;
 987         }
 988
 989         ifmsh->last_preq = jiffies;
 990
 991         if (time_after(jiffies, ifmsh->last_sn_update +
 992                                 net_traversal_jiffies(sdata)) ||
 993             time_before(jiffies, ifmsh->last_sn_update)) {
 994                 ++ifmsh->sn;
 995                 sdata->u.mesh.last_sn_update = jiffies;
 996         }
 997         lifetime = default_lifetime(sdata);
 998         ttl = sdata->u.mesh.mshcfg.element_ttl;
 999         if (ttl == 0) {
1000                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1001                 spin_unlock_bh(&mpath->state_lock);
1002                 goto enddiscovery;
1003         }
1004
1005         if (preq_node->flags & PREQ_Q_F_REFRESH)
1006                 target_flags = MP_F_DO;
1007         else
1008                 target_flags = MP_F_RF;
1009
1010         spin_unlock_bh(&mpath->state_lock);
1011         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1012         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1013                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1014                         cpu_to_le32(mpath->sn), da, 0,
1015                         ttl, cpu_to_le32(lifetime), 0,
1016                         cpu_to_le32(ifmsh->preq_id++), sdata);
1017         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1018
1019 enddiscovery:
1020         rcu_read_unlock();
1021         kfree(preq_node);
1022 }
1023
1024 /* mesh_nexthop_resolve - lookup next hop for given skb and start path
1025  * discovery if no forwarding information is found.
1026  *
1027  * @skb: 802.11 frame to be sent
1028  * @sdata: network subif the frame will be sent through
1029  *
1030  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1031  * skb is freeed here if no mpath could be allocated.
1032  */
1033 int mesh_nexthop_resolve(struct sk_buff *skb,
1034                          struct ieee80211_sub_if_data *sdata)
1035 {
1036         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1037         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1038         struct mesh_path *mpath;
1039         struct sk_buff *skb_to_free = NULL;
1040         u8 *target_addr = hdr->addr3;
1041         int err = 0;
1042
1043         rcu_read_lock();
1044         err = mesh_nexthop_lookup(skb, sdata);
1045         if (!err)
1046                 goto endlookup;
1047
1048         /* no nexthop found, start resolving */
1049         mpath = mesh_path_lookup(target_addr, sdata);
1050         if (!mpath) {
1051                 mesh_path_add(target_addr, sdata);
1052                 mpath = mesh_path_lookup(target_addr, sdata);
1053                 if (!mpath) {
1054                         mesh_path_discard_frame(skb, sdata);
1055                         err = -ENOSPC;
1056                         goto endlookup;
1057                 }
1058         }
1059
1060         if (!(mpath->flags & MESH_PATH_RESOLVING))
1061                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1062
1063         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1064                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1065
1066         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1067         ieee80211_set_qos_hdr(sdata, skb);
1068         skb_queue_tail(&mpath->frame_queue, skb);
1069         err = -ENOENT;
1070         if (skb_to_free)
1071                 mesh_path_discard_frame(skb_to_free, sdata);
1072
1073 endlookup:
1074         rcu_read_unlock();
1075         return err;
1076 }
1077 /**
1078  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1079  * this function is considered "using" the associated mpath, so preempt a path
1080  * refresh if this mpath expires soon.
1081  *
1082  * @skb: 802.11 frame to be sent
1083  * @sdata: network subif the frame will be sent through
1084  *
1085  * Returns: 0 if the next hop was found. Nonzero otherwise.
1086  */
1087 int mesh_nexthop_lookup(struct sk_buff *skb,
1088                         struct ieee80211_sub_if_data *sdata)
1089 {
1090         struct mesh_path *mpath;
1091         struct sta_info *next_hop;
1092         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1093         u8 *target_addr = hdr->addr3;
1094         int err = -ENOENT;
1095
1096         rcu_read_lock();
1097         mpath = mesh_path_lookup(target_addr, sdata);
1098
1099         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1100                 goto endlookup;
1101
1102         if (time_after(jiffies,
1103                        mpath->exp_time -
1104                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1105             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1106             !(mpath->flags & MESH_PATH_RESOLVING) &&
1107             !(mpath->flags & MESH_PATH_FIXED))
1108                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1109
1110         next_hop = rcu_dereference(mpath->next_hop);
1111         if (next_hop) {
1112                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1113                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1114                 err = 0;
1115         }
1116
1117 endlookup:
1118         rcu_read_unlock();
1119         return err;
1120 }
1121
1122 void mesh_path_timer(unsigned long data)
1123 {
1124         struct mesh_path *mpath = (void *) data;
1125         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1126         int ret;
1127
1128         if (sdata->local->quiescing)
1129                 return;
1130
1131         spin_lock_bh(&mpath->state_lock);
1132         if (mpath->flags & MESH_PATH_RESOLVED ||
1133                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1134                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1135                 spin_unlock_bh(&mpath->state_lock);
1136         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1137                 ++mpath->discovery_retries;
1138                 mpath->discovery_timeout *= 2;
1139                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1140                 spin_unlock_bh(&mpath->state_lock);
1141                 mesh_queue_preq(mpath, 0);
1142         } else {
1143                 mpath->flags = 0;
1144                 mpath->exp_time = jiffies;
1145                 spin_unlock_bh(&mpath->state_lock);
1146                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1147                         ret = mesh_path_send_to_gates(mpath);
1148                         if (ret)
1149                                 mhwmp_dbg("no gate was reachable");
1150                 } else
1151                         mesh_path_flush_pending(mpath);
1152         }
1153 }
1154
1155 void
1156 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1157 {
1158         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1159         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1160         u8 flags;
1161
1162         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1163                         ? RANN_FLAG_IS_GATE : 0;
1164         mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1165                                cpu_to_le32(++ifmsh->sn),
1166                                0, NULL, 0, broadcast_addr,
1167                                0, sdata->u.mesh.mshcfg.element_ttl,
1168                                cpu_to_le32(interval), 0, 0, sdata);
1169 }