net/mac80211/mesh_hwmp.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/etherdevice.h>
  12 #include <asm/unaligned.h>
  13 #include "wme.h"
  14 #include "mesh.h"
  15
  16 #define TEST_FRAME_LEN  8192
  17 #define MAX_METRIC      0xffffffff
  18 #define ARITH_SHIFT     8
  19
  20 #define MAX_PREQ_QUEUE_LEN      64
  21
  22 /* Destination only */
  23 #define MP_F_DO 0x1
  24 /* Reply and forward */
  25 #define MP_F_RF 0x2
  26 /* Unknown Sequence Number */
  27 #define MP_F_USN    0x01
  28 /* Reason code Present */
  29 #define MP_F_RCODE  0x02
  30
  31 static void mesh_queue_preq(struct mesh_path *, u8);
  32
  33 static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
  34 {
  35         if (ae)
  36                 offset += 6;
  37         return get_unaligned_le32(preq_elem + offset);
  38 }
  39
  40 static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
  41 {
  42         if (ae)
  43                 offset += 6;
  44         return get_unaligned_le16(preq_elem + offset);
  45 }
  46
  47 /* HWMP IE processing macros */
  48 #define AE_F                    (1<<6)
  49 #define AE_F_SET(x)             (*x & AE_F)
  50 #define PREQ_IE_FLAGS(x)        (*(x))
  51 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  52 #define PREQ_IE_TTL(x)          (*(x + 2))
  53 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  54 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  55 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  56 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  57 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  58 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  59 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  60 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  61
  62
  63 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  64 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  65 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  66 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  67 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  68 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  69 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  70 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  71 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  72
  73 #define PERR_IE_TTL(x)          (*(x))
  74 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  75 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  76 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  77 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  78
  79 #define MSEC_TO_TU(x) (x*1000/1024)
  80 #define SN_GT(x, y) ((s32)(y - x) < 0)
  81 #define SN_LT(x, y) ((s32)(x - y) < 0)
  82
  83 #define net_traversal_jiffies(s) \
  84         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  85 #define default_lifetime(s) \
  86         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  87 #define min_preq_int_jiff(s) \
  88         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  89 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  90 #define disc_timeout_jiff(s) \
  91         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  92 #define root_path_confirmation_jiffies(s) \
  93         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  94
  95 enum mpath_frame_type {
  96         MPATH_PREQ = 0,
  97         MPATH_PREP,
  98         MPATH_PERR,
  99         MPATH_RANN
 100 };
 101
 102 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 103
 104 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 105                                   const u8 *orig_addr, u32 orig_sn,
 106                                   u8 target_flags, const u8 *target,
 107                                   u32 target_sn, const u8 *da,
 108                                   u8 hop_count, u8 ttl,
 109                                   u32 lifetime, u32 metric, u32 preq_id,
 110                                   struct ieee80211_sub_if_data *sdata)
 111 {
 112         struct ieee80211_local *local = sdata->local;
 113         struct sk_buff *skb;
 114         struct ieee80211_mgmt *mgmt;
 115         u8 *pos, ie_len;
 116         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 117                       sizeof(mgmt->u.action.u.mesh_action);
 118
 119         skb = dev_alloc_skb(local->tx_headroom +
 120                             hdr_len +
 121                             2 + 37); /* max HWMP IE */
 122         if (!skb)
 123                 return -1;
 124         skb_reserve(skb, local->tx_headroom);
 125         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 126         memset(mgmt, 0, hdr_len);
 127         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 128                                           IEEE80211_STYPE_ACTION);
 129
 130         memcpy(mgmt->da, da, ETH_ALEN);
 131         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 132         /* BSSID == SA */
 133         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 134         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 135         mgmt->u.action.u.mesh_action.action_code =
 136                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 137
 138         switch (action) {
 139         case MPATH_PREQ:
 140                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 141                 ie_len = 37;
 142                 pos = skb_put(skb, 2 + ie_len);
 143                 *pos++ = WLAN_EID_PREQ;
 144                 break;
 145         case MPATH_PREP:
 146                 mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
 147                 ie_len = 31;
 148                 pos = skb_put(skb, 2 + ie_len);
 149                 *pos++ = WLAN_EID_PREP;
 150                 break;
 151         case MPATH_RANN:
 152                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 153                 ie_len = sizeof(struct ieee80211_rann_ie);
 154                 pos = skb_put(skb, 2 + ie_len);
 155                 *pos++ = WLAN_EID_RANN;
 156                 break;
 157         default:
 158                 kfree_skb(skb);
 159                 return -ENOTSUPP;
 160         }
 161         *pos++ = ie_len;
 162         *pos++ = flags;
 163         *pos++ = hop_count;
 164         *pos++ = ttl;
 165         if (action == MPATH_PREP) {
 166                 memcpy(pos, target, ETH_ALEN);
 167                 pos += ETH_ALEN;
 168                 put_unaligned_le32(target_sn, pos);
 169                 pos += 4;
 170         } else {
 171                 if (action == MPATH_PREQ) {
 172                         put_unaligned_le32(preq_id, pos);
 173                         pos += 4;
 174                 }
 175                 memcpy(pos, orig_addr, ETH_ALEN);
 176                 pos += ETH_ALEN;
 177                 put_unaligned_le32(orig_sn, pos);
 178                 pos += 4;
 179         }
 180         put_unaligned_le32(lifetime, pos); /* interval for RANN */
 181         pos += 4;
 182         put_unaligned_le32(metric, pos);
 183         pos += 4;
 184         if (action == MPATH_PREQ) {
 185                 *pos++ = 1; /* destination count */
 186                 *pos++ = target_flags;
 187                 memcpy(pos, target, ETH_ALEN);
 188                 pos += ETH_ALEN;
 189                 put_unaligned_le32(target_sn, pos);
 190                 pos += 4;
 191         } else if (action == MPATH_PREP) {
 192                 memcpy(pos, orig_addr, ETH_ALEN);
 193                 pos += ETH_ALEN;
 194                 put_unaligned_le32(orig_sn, pos);
 195                 pos += 4;
 196         }
 197
 198         ieee80211_tx_skb(sdata, skb);
 199         return 0;
 200 }
 201
 202
 203 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 204  *  headroom in case the frame is encrypted. */
 205 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 206                 struct sk_buff *skb)
 207 {
 208         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 209         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 210
 211         skb_set_mac_header(skb, 0);
 212         skb_set_network_header(skb, 0);
 213         skb_set_transport_header(skb, 0);
 214
 215         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 216         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 217         skb->priority = 7;
 218
 219         info->control.vif = &sdata->vif;
 220         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 221         ieee80211_set_qos_hdr(sdata, skb);
 222         ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
 223 }
 224
 225 /**
 226  * mesh_path_error_tx - Sends a PERR mesh management frame
 227  *
 228  * @ttl: allowed remaining hops
 229  * @target: broken destination
 230  * @target_sn: SN of the broken destination
 231  * @target_rcode: reason code for this PERR
 232  * @ra: node this frame is addressed to
 233  * @sdata: local mesh subif
 234  *
 235  * Note: This function may be called with driver locks taken that the driver
 236  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 237  * frame directly but add it to the pending queue instead.
 238  */
 239 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 240                        u8 ttl, const u8 *target, u32 target_sn,
 241                        u16 target_rcode, const u8 *ra)
 242 {
 243         struct ieee80211_local *local = sdata->local;
 244         struct sk_buff *skb;
 245         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 246         struct ieee80211_mgmt *mgmt;
 247         u8 *pos, ie_len;
 248         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 249                       sizeof(mgmt->u.action.u.mesh_action);
 250
 251         if (time_before(jiffies, ifmsh->next_perr))
 252                 return -EAGAIN;
 253
 254         skb = dev_alloc_skb(local->tx_headroom +
 255                             sdata->encrypt_headroom +
 256                             IEEE80211_ENCRYPT_TAILROOM +
 257                             hdr_len +
 258                             2 + 15 /* PERR IE */);
 259         if (!skb)
 260                 return -1;
 261         skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom);
 262         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 263         memset(mgmt, 0, hdr_len);
 264         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 265                                           IEEE80211_STYPE_ACTION);
 266
 267         memcpy(mgmt->da, ra, ETH_ALEN);
 268         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 269         /* BSSID == SA */
 270         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 271         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 272         mgmt->u.action.u.mesh_action.action_code =
 273                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 274         ie_len = 15;
 275         pos = skb_put(skb, 2 + ie_len);
 276         *pos++ = WLAN_EID_PERR;
 277         *pos++ = ie_len;
 278         /* ttl */
 279         *pos++ = ttl;
 280         /* number of destinations */
 281         *pos++ = 1;
 282         /*
 283          * flags bit, bit 1 is unset if we know the sequence number and
 284          * bit 2 is set if we have a reason code
 285          */
 286         *pos = 0;
 287         if (!target_sn)
 288                 *pos |= MP_F_USN;
 289         if (target_rcode)
 290                 *pos |= MP_F_RCODE;
 291         pos++;
 292         memcpy(pos, target, ETH_ALEN);
 293         pos += ETH_ALEN;
 294         put_unaligned_le32(target_sn, pos);
 295         pos += 4;
 296         put_unaligned_le16(target_rcode, pos);
 297
 298         /* see note in function header */
 299         prepare_frame_for_deferred_tx(sdata, skb);
 300         ifmsh->next_perr = TU_TO_EXP_TIME(
 301                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 302         ieee80211_add_pending_skb(local, skb);
 303         return 0;
 304 }
 305
 306 void ieee80211s_update_metric(struct ieee80211_local *local,
 307                 struct sta_info *sta, struct sk_buff *skb)
 308 {
 309         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 310         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 311         int failed;
 312
 313         if (!ieee80211_is_data(hdr->frame_control))
 314                 return;
 315
 316         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 317
 318         /* moving average, scaled to 100 */
 319         sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
 320         if (sta->fail_avg > 95)
 321                 mesh_plink_broken(sta);
 322 }
 323
 324 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 325                                    struct sta_info *sta)
 326 {
 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         if (sta->fail_avg >= 100)
 337                 return MAX_METRIC;
 338
 339         sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
 340         rate = cfg80211_calculate_bitrate(&rinfo);
 341         if (WARN_ON(!rate))
 342                 return MAX_METRIC;
 343
 344         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 345
 346         /* bitrate is in units of 100 Kbps, while we need rate in units of
 347          * 1Mbps. This will be corrected on tx_time computation.
 348          */
 349         tx_time = (device_constant + 10 * test_frame_len / rate);
 350         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 351         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 352         return (u32)result;
 353 }
 354
 355 /**
 356  * hwmp_route_info_get - Update routing info to originator and transmitter
 357  *
 358  * @sdata: local mesh subif
 359  * @mgmt: mesh management frame
 360  * @hwmp_ie: hwmp information element (PREP or PREQ)
 361  * @action: type of hwmp ie
 362  *
 363  * This function updates the path routing information to the originator and the
 364  * transmitter of a HWMP PREQ or PREP frame.
 365  *
 366  * Returns: metric to frame originator or 0 if the frame should not be further
 367  * processed
 368  *
 369  * Notes: this function is the only place (besides user-provided info) where
 370  * path routing information is updated.
 371  */
 372 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 373                                struct ieee80211_mgmt *mgmt,
 374                                const u8 *hwmp_ie, enum mpath_frame_type action)
 375 {
 376         struct ieee80211_local *local = sdata->local;
 377         struct mesh_path *mpath;
 378         struct sta_info *sta;
 379         bool fresh_info;
 380         const u8 *orig_addr, *ta;
 381         u32 orig_sn, orig_metric;
 382         unsigned long orig_lifetime, exp_time;
 383         u32 last_hop_metric, new_metric;
 384         bool process = true;
 385
 386         rcu_read_lock();
 387         sta = sta_info_get(sdata, mgmt->sa);
 388         if (!sta) {
 389                 rcu_read_unlock();
 390                 return 0;
 391         }
 392
 393         last_hop_metric = airtime_link_metric_get(local, sta);
 394         /* Update and check originator routing info */
 395         fresh_info = true;
 396
 397         switch (action) {
 398         case MPATH_PREQ:
 399                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 400                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 401                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 402                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 403                 break;
 404         case MPATH_PREP:
 405                 /* Originator here refers to the MP that was the target in the
 406                  * Path Request. We divert from the nomenclature in the draft
 407                  * so that we can easily use a single function to gather path
 408                  * information from both PREQ and PREP frames.
 409                  */
 410                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 411                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 412                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 413                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 414                 break;
 415         default:
 416                 rcu_read_unlock();
 417                 return 0;
 418         }
 419         new_metric = orig_metric + last_hop_metric;
 420         if (new_metric < orig_metric)
 421                 new_metric = MAX_METRIC;
 422         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 423
 424         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 425                 /* This MP is the originator, we are not interested in this
 426                  * frame, except for updating transmitter's path info.
 427                  */
 428                 process = false;
 429                 fresh_info = false;
 430         } else {
 431                 mpath = mesh_path_lookup(sdata, orig_addr);
 432                 if (mpath) {
 433                         spin_lock_bh(&mpath->state_lock);
 434                         if (mpath->flags & MESH_PATH_FIXED)
 435                                 fresh_info = false;
 436                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 437                             (mpath->flags & MESH_PATH_SN_VALID)) {
 438                                 if (SN_GT(mpath->sn, orig_sn) ||
 439                                     (mpath->sn == orig_sn &&
 440                                      new_metric >= mpath->metric)) {
 441                                         process = false;
 442                                         fresh_info = false;
 443                                 }
 444                         }
 445                 } else {
 446                         mpath = mesh_path_add(sdata, orig_addr);
 447                         if (IS_ERR(mpath)) {
 448                                 rcu_read_unlock();
 449                                 return 0;
 450                         }
 451                         spin_lock_bh(&mpath->state_lock);
 452                 }
 453
 454                 if (fresh_info) {
 455                         mesh_path_assign_nexthop(mpath, sta);
 456                         mpath->flags |= MESH_PATH_SN_VALID;
 457                         mpath->metric = new_metric;
 458                         mpath->sn = orig_sn;
 459                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 460                                           ?  mpath->exp_time : exp_time;
 461                         mesh_path_activate(mpath);
 462                         spin_unlock_bh(&mpath->state_lock);
 463                         mesh_path_tx_pending(mpath);
 464                         /* draft says preq_id should be saved to, but there does
 465                          * not seem to be any use for it, skipping by now
 466                          */
 467                 } else
 468                         spin_unlock_bh(&mpath->state_lock);
 469         }
 470
 471         /* Update and check transmitter routing info */
 472         ta = mgmt->sa;
 473         if (ether_addr_equal(orig_addr, ta))
 474                 fresh_info = false;
 475         else {
 476                 fresh_info = true;
 477
 478                 mpath = mesh_path_lookup(sdata, ta);
 479                 if (mpath) {
 480                         spin_lock_bh(&mpath->state_lock);
 481                         if ((mpath->flags & MESH_PATH_FIXED) ||
 482                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 483                                         (last_hop_metric > mpath->metric)))
 484                                 fresh_info = false;
 485                 } else {
 486                         mpath = mesh_path_add(sdata, ta);
 487                         if (IS_ERR(mpath)) {
 488                                 rcu_read_unlock();
 489                                 return 0;
 490                         }
 491                         spin_lock_bh(&mpath->state_lock);
 492                 }
 493
 494                 if (fresh_info) {
 495                         mesh_path_assign_nexthop(mpath, sta);
 496                         mpath->metric = last_hop_metric;
 497                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 498                                           ?  mpath->exp_time : exp_time;
 499                         mesh_path_activate(mpath);
 500                         spin_unlock_bh(&mpath->state_lock);
 501                         mesh_path_tx_pending(mpath);
 502                 } else
 503                         spin_unlock_bh(&mpath->state_lock);
 504         }
 505
 506         rcu_read_unlock();
 507
 508         return process ? new_metric : 0;
 509 }
 510
 511 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 512                                     struct ieee80211_mgmt *mgmt,
 513                                     const u8 *preq_elem, u32 orig_metric)
 514 {
 515         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 516         struct mesh_path *mpath = NULL;
 517         const u8 *target_addr, *orig_addr;
 518         const u8 *da;
 519         u8 target_flags, ttl, flags;
 520         u32 orig_sn, target_sn, lifetime, target_metric;
 521         bool reply = false;
 522         bool forward = true;
 523         bool root_is_gate;
 524
 525         /* Update target SN, if present */
 526         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 527         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 528         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 529         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 530         target_flags = PREQ_IE_TARGET_F(preq_elem);
 531         /* Proactive PREQ gate announcements */
 532         flags = PREQ_IE_FLAGS(preq_elem);
 533         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 534
 535         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 536
 537         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 538                 mhwmp_dbg(sdata, "PREQ is for us\n");
 539                 forward = false;
 540                 reply = true;
 541                 target_metric = 0;
 542                 if (time_after(jiffies, ifmsh->last_sn_update +
 543                                         net_traversal_jiffies(sdata)) ||
 544                     time_before(jiffies, ifmsh->last_sn_update)) {
 545                         ++ifmsh->sn;
 546                         ifmsh->last_sn_update = jiffies;
 547                 }
 548                 target_sn = ifmsh->sn;
 549         } else if (is_broadcast_ether_addr(target_addr) &&
 550                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 551                 rcu_read_lock();
 552                 mpath = mesh_path_lookup(sdata, orig_addr);
 553                 if (mpath) {
 554                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 555                                 reply = true;
 556                                 target_addr = sdata->vif.addr;
 557                                 target_sn = ++ifmsh->sn;
 558                                 target_metric = 0;
 559                                 ifmsh->last_sn_update = jiffies;
 560                         }
 561                         if (root_is_gate)
 562                                 mesh_path_add_gate(mpath);
 563                 }
 564                 rcu_read_unlock();
 565         } else {
 566                 rcu_read_lock();
 567                 mpath = mesh_path_lookup(sdata, target_addr);
 568                 if (mpath) {
 569                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 570                                         SN_LT(mpath->sn, target_sn)) {
 571                                 mpath->sn = target_sn;
 572                                 mpath->flags |= MESH_PATH_SN_VALID;
 573                         } else if ((!(target_flags & MP_F_DO)) &&
 574                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 575                                 reply = true;
 576                                 target_metric = mpath->metric;
 577                                 target_sn = mpath->sn;
 578                                 if (target_flags & MP_F_RF)
 579                                         target_flags |= MP_F_DO;
 580                                 else
 581                                         forward = false;
 582                         }
 583                 }
 584                 rcu_read_unlock();
 585         }
 586
 587         if (reply) {
 588                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 589                 ttl = ifmsh->mshcfg.element_ttl;
 590                 if (ttl != 0) {
 591                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 592                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 593                                                orig_sn, 0, target_addr,
 594                                                target_sn, mgmt->sa, 0, ttl,
 595                                                lifetime, target_metric, 0,
 596                                                sdata);
 597                 } else {
 598                         ifmsh->mshstats.dropped_frames_ttl++;
 599                 }
 600         }
 601
 602         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 603                 u32 preq_id;
 604                 u8 hopcount;
 605
 606                 ttl = PREQ_IE_TTL(preq_elem);
 607                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 608                 if (ttl <= 1) {
 609                         ifmsh->mshstats.dropped_frames_ttl++;
 610                         return;
 611                 }
 612                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 613                 --ttl;
 614                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 615                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 616                 da = (mpath && mpath->is_root) ?
 617                         mpath->rann_snd_addr : broadcast_addr;
 618
 619                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 620                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 621                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 622                 }
 623
 624                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 625                                        orig_sn, target_flags, target_addr,
 626                                        target_sn, da, hopcount, ttl, lifetime,
 627                                        orig_metric, preq_id, sdata);
 628                 if (!is_multicast_ether_addr(da))
 629                         ifmsh->mshstats.fwded_unicast++;
 630                 else
 631                         ifmsh->mshstats.fwded_mcast++;
 632                 ifmsh->mshstats.fwded_frames++;
 633         }
 634 }
 635
 636
 637 static inline struct sta_info *
 638 next_hop_deref_protected(struct mesh_path *mpath)
 639 {
 640         return rcu_dereference_protected(mpath->next_hop,
 641                                          lockdep_is_held(&mpath->state_lock));
 642 }
 643
 644
 645 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 646                                     struct ieee80211_mgmt *mgmt,
 647                                     const u8 *prep_elem, u32 metric)
 648 {
 649         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 650         struct mesh_path *mpath;
 651         const u8 *target_addr, *orig_addr;
 652         u8 ttl, hopcount, flags;
 653         u8 next_hop[ETH_ALEN];
 654         u32 target_sn, orig_sn, lifetime;
 655
 656         mhwmp_dbg(sdata, "received PREP from %pM\n",
 657                   PREP_IE_TARGET_ADDR(prep_elem));
 658
 659         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 660         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 661                 /* destination, no forwarding required */
 662                 return;
 663
 664         if (!ifmsh->mshcfg.dot11MeshForwarding)
 665                 return;
 666
 667         ttl = PREP_IE_TTL(prep_elem);
 668         if (ttl <= 1) {
 669                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 670                 return;
 671         }
 672
 673         rcu_read_lock();
 674         mpath = mesh_path_lookup(sdata, orig_addr);
 675         if (mpath)
 676                 spin_lock_bh(&mpath->state_lock);
 677         else
 678                 goto fail;
 679         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 680                 spin_unlock_bh(&mpath->state_lock);
 681                 goto fail;
 682         }
 683         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 684         spin_unlock_bh(&mpath->state_lock);
 685         --ttl;
 686         flags = PREP_IE_FLAGS(prep_elem);
 687         lifetime = PREP_IE_LIFETIME(prep_elem);
 688         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 689         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 690         target_sn = PREP_IE_TARGET_SN(prep_elem);
 691         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 692
 693         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 694                                target_addr, target_sn, next_hop, hopcount,
 695                                ttl, lifetime, metric, 0, sdata);
 696         rcu_read_unlock();
 697
 698         sdata->u.mesh.mshstats.fwded_unicast++;
 699         sdata->u.mesh.mshstats.fwded_frames++;
 700         return;
 701
 702 fail:
 703         rcu_read_unlock();
 704         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 705 }
 706
 707 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 708                                     struct ieee80211_mgmt *mgmt,
 709                                     const u8 *perr_elem)
 710 {
 711         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 712         struct mesh_path *mpath;
 713         u8 ttl;
 714         const u8 *ta, *target_addr;
 715         u32 target_sn;
 716         u16 target_rcode;
 717
 718         ta = mgmt->sa;
 719         ttl = PERR_IE_TTL(perr_elem);
 720         if (ttl <= 1) {
 721                 ifmsh->mshstats.dropped_frames_ttl++;
 722                 return;
 723         }
 724         ttl--;
 725         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 726         target_sn = PERR_IE_TARGET_SN(perr_elem);
 727         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 728
 729         rcu_read_lock();
 730         mpath = mesh_path_lookup(sdata, target_addr);
 731         if (mpath) {
 732                 struct sta_info *sta;
 733
 734                 spin_lock_bh(&mpath->state_lock);
 735                 sta = next_hop_deref_protected(mpath);
 736                 if (mpath->flags & MESH_PATH_ACTIVE &&
 737                     ether_addr_equal(ta, sta->sta.addr) &&
 738                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 739                     SN_GT(target_sn, mpath->sn))) {
 740                         mpath->flags &= ~MESH_PATH_ACTIVE;
 741                         mpath->sn = target_sn;
 742                         spin_unlock_bh(&mpath->state_lock);
 743                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 744                                 goto endperr;
 745                         mesh_path_error_tx(sdata, ttl, target_addr,
 746                                            target_sn, target_rcode,
 747                                            broadcast_addr);
 748                 } else
 749                         spin_unlock_bh(&mpath->state_lock);
 750         }
 751 endperr:
 752         rcu_read_unlock();
 753 }
 754
 755 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 756                                     struct ieee80211_mgmt *mgmt,
 757                                     const struct ieee80211_rann_ie *rann)
 758 {
 759         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 760         struct ieee80211_local *local = sdata->local;
 761         struct sta_info *sta;
 762         struct mesh_path *mpath;
 763         u8 ttl, flags, hopcount;
 764         const u8 *orig_addr;
 765         u32 orig_sn, metric, metric_txsta, interval;
 766         bool root_is_gate;
 767
 768         ttl = rann->rann_ttl;
 769         flags = rann->rann_flags;
 770         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 771         orig_addr = rann->rann_addr;
 772         orig_sn = le32_to_cpu(rann->rann_seq);
 773         interval = le32_to_cpu(rann->rann_interval);
 774         hopcount = rann->rann_hopcount;
 775         hopcount++;
 776         metric = le32_to_cpu(rann->rann_metric);
 777
 778         /*  Ignore our own RANNs */
 779         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 780                 return;
 781
 782         mhwmp_dbg(sdata,
 783                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 784                   orig_addr, mgmt->sa, root_is_gate);
 785
 786         rcu_read_lock();
 787         sta = sta_info_get(sdata, mgmt->sa);
 788         if (!sta) {
 789                 rcu_read_unlock();
 790                 return;
 791         }
 792
 793         metric_txsta = airtime_link_metric_get(local, sta);
 794
 795         mpath = mesh_path_lookup(sdata, orig_addr);
 796         if (!mpath) {
 797                 mpath = mesh_path_add(sdata, orig_addr);
 798                 if (IS_ERR(mpath)) {
 799                         rcu_read_unlock();
 800                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 801                         return;
 802                 }
 803         }
 804
 805         if (!(SN_LT(mpath->sn, orig_sn)) &&
 806             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 807                 rcu_read_unlock();
 808                 return;
 809         }
 810
 811         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 812              (time_after(jiffies, mpath->last_preq_to_root +
 813                                   root_path_confirmation_jiffies(sdata)) ||
 814              time_before(jiffies, mpath->last_preq_to_root))) &&
 815              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 816                 mhwmp_dbg(sdata,
 817                           "time to refresh root mpath %pM\n",
 818                           orig_addr);
 819                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 820                 mpath->last_preq_to_root = jiffies;
 821         }
 822
 823         mpath->sn = orig_sn;
 824         mpath->rann_metric = metric + metric_txsta;
 825         mpath->is_root = true;
 826         /* Recording RANNs sender address to send individually
 827          * addressed PREQs destined for root mesh STA */
 828         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 829
 830         if (root_is_gate)
 831                 mesh_path_add_gate(mpath);
 832
 833         if (ttl <= 1) {
 834                 ifmsh->mshstats.dropped_frames_ttl++;
 835                 rcu_read_unlock();
 836                 return;
 837         }
 838         ttl--;
 839
 840         if (ifmsh->mshcfg.dot11MeshForwarding) {
 841                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 842                                        orig_sn, 0, NULL, 0, broadcast_addr,
 843                                        hopcount, ttl, interval,
 844                                        metric + metric_txsta, 0, sdata);
 845         }
 846
 847         rcu_read_unlock();
 848 }
 849
 850
 851 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 852                             struct ieee80211_mgmt *mgmt, size_t len)
 853 {
 854         struct ieee802_11_elems elems;
 855         size_t baselen;
 856         u32 path_metric;
 857         struct sta_info *sta;
 858
 859         /* need action_code */
 860         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 861                 return;
 862
 863         rcu_read_lock();
 864         sta = sta_info_get(sdata, mgmt->sa);
 865         if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 866                 rcu_read_unlock();
 867                 return;
 868         }
 869         rcu_read_unlock();
 870
 871         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 872         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 873                                len - baselen, false, &elems);
 874
 875         if (elems.preq) {
 876                 if (elems.preq_len != 37)
 877                         /* Right now we support just 1 destination and no AE */
 878                         return;
 879                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 880                                                   MPATH_PREQ);
 881                 if (path_metric)
 882                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 883                                                 path_metric);
 884         }
 885         if (elems.prep) {
 886                 if (elems.prep_len != 31)
 887                         /* Right now we support no AE */
 888                         return;
 889                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 890                                                   MPATH_PREP);
 891                 if (path_metric)
 892                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 893                                                 path_metric);
 894         }
 895         if (elems.perr) {
 896                 if (elems.perr_len != 15)
 897                         /* Right now we support only one destination per PERR */
 898                         return;
 899                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 900         }
 901         if (elems.rann)
 902                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 903 }
 904
 905 /**
 906  * mesh_queue_preq - queue a PREQ to a given destination
 907  *
 908  * @mpath: mesh path to discover
 909  * @flags: special attributes of the PREQ to be sent
 910  *
 911  * Locking: the function must be called from within a rcu read lock block.
 912  *
 913  */
 914 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 915 {
 916         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 917         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 918         struct mesh_preq_queue *preq_node;
 919
 920         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 921         if (!preq_node) {
 922                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 923                 return;
 924         }
 925
 926         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 927         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 928                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 929                 kfree(preq_node);
 930                 if (printk_ratelimit())
 931                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 932                 return;
 933         }
 934
 935         spin_lock(&mpath->state_lock);
 936         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 937                 spin_unlock(&mpath->state_lock);
 938                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 939                 kfree(preq_node);
 940                 return;
 941         }
 942
 943         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 944         preq_node->flags = flags;
 945
 946         mpath->flags |= MESH_PATH_REQ_QUEUED;
 947         spin_unlock(&mpath->state_lock);
 948
 949         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 950         ++ifmsh->preq_queue_len;
 951         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 952
 953         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 954                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 955
 956         else if (time_before(jiffies, ifmsh->last_preq)) {
 957                 /* avoid long wait if did not send preqs for a long time
 958                  * and jiffies wrapped around
 959                  */
 960                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 961                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 962         } else
 963                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 964                                                 min_preq_int_jiff(sdata));
 965 }
 966
 967 /**
 968  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 969  *
 970  * @sdata: local mesh subif
 971  */
 972 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 973 {
 974         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 975         struct mesh_preq_queue *preq_node;
 976         struct mesh_path *mpath;
 977         u8 ttl, target_flags;
 978         const u8 *da;
 979         u32 lifetime;
 980
 981         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 982         if (!ifmsh->preq_queue_len ||
 983                 time_before(jiffies, ifmsh->last_preq +
 984                                 min_preq_int_jiff(sdata))) {
 985                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 986                 return;
 987         }
 988
 989         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 990                         struct mesh_preq_queue, list);
 991         list_del(&preq_node->list);
 992         --ifmsh->preq_queue_len;
 993         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 994
 995         rcu_read_lock();
 996         mpath = mesh_path_lookup(sdata, preq_node->dst);
 997         if (!mpath)
 998                 goto enddiscovery;
 999
1000         spin_lock_bh(&mpath->state_lock);
1001         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1002         if (preq_node->flags & PREQ_Q_F_START) {
1003                 if (mpath->flags & MESH_PATH_RESOLVING) {
1004                         spin_unlock_bh(&mpath->state_lock);
1005                         goto enddiscovery;
1006                 } else {
1007                         mpath->flags &= ~MESH_PATH_RESOLVED;
1008                         mpath->flags |= MESH_PATH_RESOLVING;
1009                         mpath->discovery_retries = 0;
1010                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1011                 }
1012         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1013                         mpath->flags & MESH_PATH_RESOLVED) {
1014                 mpath->flags &= ~MESH_PATH_RESOLVING;
1015                 spin_unlock_bh(&mpath->state_lock);
1016                 goto enddiscovery;
1017         }
1018
1019         ifmsh->last_preq = jiffies;
1020
1021         if (time_after(jiffies, ifmsh->last_sn_update +
1022                                 net_traversal_jiffies(sdata)) ||
1023             time_before(jiffies, ifmsh->last_sn_update)) {
1024                 ++ifmsh->sn;
1025                 sdata->u.mesh.last_sn_update = jiffies;
1026         }
1027         lifetime = default_lifetime(sdata);
1028         ttl = sdata->u.mesh.mshcfg.element_ttl;
1029         if (ttl == 0) {
1030                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1031                 spin_unlock_bh(&mpath->state_lock);
1032                 goto enddiscovery;
1033         }
1034
1035         if (preq_node->flags & PREQ_Q_F_REFRESH)
1036                 target_flags = MP_F_DO;
1037         else
1038                 target_flags = MP_F_RF;
1039
1040         spin_unlock_bh(&mpath->state_lock);
1041         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1042         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1043                                target_flags, mpath->dst, mpath->sn, da, 0,
1044                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1045         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1046
1047 enddiscovery:
1048         rcu_read_unlock();
1049         kfree(preq_node);
1050 }
1051
1052 /**
1053  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1054  *
1055  * @skb: 802.11 frame to be sent
1056  * @sdata: network subif the frame will be sent through
1057  *
1058  * Lookup next hop for given skb and start path discovery if no
1059  * forwarding information is found.
1060  *
1061  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1062  * skb is freeed here if no mpath could be allocated.
1063  */
1064 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1065                          struct sk_buff *skb)
1066 {
1067         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1068         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1069         struct mesh_path *mpath;
1070         struct sk_buff *skb_to_free = NULL;
1071         u8 *target_addr = hdr->addr3;
1072         int err = 0;
1073
1074         /* Nulls are only sent to peers for PS and should be pre-addressed */
1075         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1076                 return 0;
1077
1078         rcu_read_lock();
1079         err = mesh_nexthop_lookup(sdata, skb);
1080         if (!err)
1081                 goto endlookup;
1082
1083         /* no nexthop found, start resolving */
1084         mpath = mesh_path_lookup(sdata, target_addr);
1085         if (!mpath) {
1086                 mpath = mesh_path_add(sdata, target_addr);
1087                 if (IS_ERR(mpath)) {
1088                         mesh_path_discard_frame(sdata, skb);
1089                         err = PTR_ERR(mpath);
1090                         goto endlookup;
1091                 }
1092         }
1093
1094         if (!(mpath->flags & MESH_PATH_RESOLVING))
1095                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1096
1097         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1098                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1099
1100         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1101         ieee80211_set_qos_hdr(sdata, skb);
1102         skb_queue_tail(&mpath->frame_queue, skb);
1103         err = -ENOENT;
1104         if (skb_to_free)
1105                 mesh_path_discard_frame(sdata, skb_to_free);
1106
1107 endlookup:
1108         rcu_read_unlock();
1109         return err;
1110 }
1111
1112 /**
1113  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1114  * this function is considered "using" the associated mpath, so preempt a path
1115  * refresh if this mpath expires soon.
1116  *
1117  * @skb: 802.11 frame to be sent
1118  * @sdata: network subif the frame will be sent through
1119  *
1120  * Returns: 0 if the next hop was found. Nonzero otherwise.
1121  */
1122 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1123                         struct sk_buff *skb)
1124 {
1125         struct mesh_path *mpath;
1126         struct sta_info *next_hop;
1127         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1128         u8 *target_addr = hdr->addr3;
1129         int err = -ENOENT;
1130
1131         rcu_read_lock();
1132         mpath = mesh_path_lookup(sdata, target_addr);
1133
1134         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1135                 goto endlookup;
1136
1137         if (time_after(jiffies,
1138                        mpath->exp_time -
1139                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1140             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1141             !(mpath->flags & MESH_PATH_RESOLVING) &&
1142             !(mpath->flags & MESH_PATH_FIXED))
1143                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1144
1145         next_hop = rcu_dereference(mpath->next_hop);
1146         if (next_hop) {
1147                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1148                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1149                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1150                 err = 0;
1151         }
1152
1153 endlookup:
1154         rcu_read_unlock();
1155         return err;
1156 }
1157
1158 void mesh_path_timer(unsigned long data)
1159 {
1160         struct mesh_path *mpath = (void *) data;
1161         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1162         int ret;
1163
1164         if (sdata->local->quiescing)
1165                 return;
1166
1167         spin_lock_bh(&mpath->state_lock);
1168         if (mpath->flags & MESH_PATH_RESOLVED ||
1169                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1170                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1171                 spin_unlock_bh(&mpath->state_lock);
1172         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1173                 ++mpath->discovery_retries;
1174                 mpath->discovery_timeout *= 2;
1175                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1176                 spin_unlock_bh(&mpath->state_lock);
1177                 mesh_queue_preq(mpath, 0);
1178         } else {
1179                 mpath->flags = 0;
1180                 mpath->exp_time = jiffies;
1181                 spin_unlock_bh(&mpath->state_lock);
1182                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1183                         ret = mesh_path_send_to_gates(mpath);
1184                         if (ret)
1185                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1186                 } else
1187                         mesh_path_flush_pending(mpath);
1188         }
1189 }
1190
1191 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1192 {
1193         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1194         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1195         u8 flags, target_flags = 0;
1196
1197         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1198                         ? RANN_FLAG_IS_GATE : 0;
1199
1200         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1201         case IEEE80211_PROACTIVE_RANN:
1202                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1203                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1204                                        0, ifmsh->mshcfg.element_ttl,
1205                                        interval, 0, 0, sdata);
1206                 break;
1207         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1208                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1209         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1210                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1211                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1212                                 IEEE80211_PREQ_USN_FLAG;
1213                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1214                                        ++ifmsh->sn, target_flags,
1215                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1216                                        0, ifmsh->mshcfg.element_ttl, interval,
1217                                        0, ifmsh->preq_id++, sdata);
1218                 break;
1219         default:
1220                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1221                 return;
1222         }
1223 }