Pileus Git - ~andy/linux/blob - 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 u32 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, __le32 orig_sn,
 106                                   u8 target_flags, const u8 *target,
 107                                   __le32 target_sn, const u8 *da,
 108                                   u8 hop_count, u8 ttl,
 109                                   __le32 lifetime, __le32 metric,
 110                                   __le32 preq_id,
 111                                   struct ieee80211_sub_if_data *sdata)
 112 {
 113         struct ieee80211_local *local = sdata->local;
 114         struct sk_buff *skb;
 115         struct ieee80211_mgmt *mgmt;
 116         u8 *pos, ie_len;
 117         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 118                       sizeof(mgmt->u.action.u.mesh_action);
 119
 120         skb = dev_alloc_skb(local->tx_headroom +
 121                             hdr_len +
 122                             2 + 37); /* max HWMP IE */
 123         if (!skb)
 124                 return -1;
 125         skb_reserve(skb, local->tx_headroom);
 126         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 127         memset(mgmt, 0, hdr_len);
 128         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 129                                           IEEE80211_STYPE_ACTION);
 130
 131         memcpy(mgmt->da, da, ETH_ALEN);
 132         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 133         /* BSSID == SA */
 134         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 135         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 136         mgmt->u.action.u.mesh_action.action_code =
 137                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 138
 139         switch (action) {
 140         case MPATH_PREQ:
 141                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 142                 ie_len = 37;
 143                 pos = skb_put(skb, 2 + ie_len);
 144                 *pos++ = WLAN_EID_PREQ;
 145                 break;
 146         case MPATH_PREP:
 147                 mhwmp_dbg(sdata, "sending PREP to %pM\n", target);
 148                 ie_len = 31;
 149                 pos = skb_put(skb, 2 + ie_len);
 150                 *pos++ = WLAN_EID_PREP;
 151                 break;
 152         case MPATH_RANN:
 153                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 154                 ie_len = sizeof(struct ieee80211_rann_ie);
 155                 pos = skb_put(skb, 2 + ie_len);
 156                 *pos++ = WLAN_EID_RANN;
 157                 break;
 158         default:
 159                 kfree_skb(skb);
 160                 return -ENOTSUPP;
 161                 break;
 162         }
 163         *pos++ = ie_len;
 164         *pos++ = flags;
 165         *pos++ = hop_count;
 166         *pos++ = ttl;
 167         if (action == MPATH_PREP) {
 168                 memcpy(pos, target, ETH_ALEN);
 169                 pos += ETH_ALEN;
 170                 memcpy(pos, &target_sn, 4);
 171                 pos += 4;
 172         } else {
 173                 if (action == MPATH_PREQ) {
 174                         memcpy(pos, &preq_id, 4);
 175                         pos += 4;
 176                 }
 177                 memcpy(pos, orig_addr, ETH_ALEN);
 178                 pos += ETH_ALEN;
 179                 memcpy(pos, &orig_sn, 4);
 180                 pos += 4;
 181         }
 182         memcpy(pos, &lifetime, 4);      /* interval for RANN */
 183         pos += 4;
 184         memcpy(pos, &metric, 4);
 185         pos += 4;
 186         if (action == MPATH_PREQ) {
 187                 *pos++ = 1; /* destination count */
 188                 *pos++ = target_flags;
 189                 memcpy(pos, target, ETH_ALEN);
 190                 pos += ETH_ALEN;
 191                 memcpy(pos, &target_sn, 4);
 192                 pos += 4;
 193         } else if (action == MPATH_PREP) {
 194                 memcpy(pos, orig_addr, ETH_ALEN);
 195                 pos += ETH_ALEN;
 196                 memcpy(pos, &orig_sn, 4);
 197                 pos += 4;
 198         }
 199
 200         ieee80211_tx_skb(sdata, skb);
 201         return 0;
 202 }
 203
 204
 205 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 206  *  headroom in case the frame is encrypted. */
 207 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 208                 struct sk_buff *skb)
 209 {
 210         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 211         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 212
 213         skb_set_mac_header(skb, 0);
 214         skb_set_network_header(skb, 0);
 215         skb_set_transport_header(skb, 0);
 216
 217         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 218         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 219         skb->priority = 7;
 220
 221         info->control.vif = &sdata->vif;
 222         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 223         ieee80211_set_qos_hdr(sdata, skb);
 224         ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
 225 }
 226
 227 /**
 228  * mesh_path_error_tx - Sends a PERR mesh management frame
 229  *
 230  * @ttl: allowed remaining hops
 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  * @sdata: local mesh subif
 236  *
 237  * Note: This function may be called with driver locks taken that the driver
 238  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 239  * frame directly but add it to the pending queue instead.
 240  */
 241 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 242                        u8 ttl, const u8 *target, __le32 target_sn,
 243                        __le16 target_rcode, const u8 *ra)
 244 {
 245         struct ieee80211_local *local = sdata->local;
 246         struct sk_buff *skb;
 247         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 248         struct ieee80211_mgmt *mgmt;
 249         u8 *pos, ie_len;
 250         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 251                       sizeof(mgmt->u.action.u.mesh_action);
 252
 253         if (time_before(jiffies, ifmsh->next_perr))
 254                 return -EAGAIN;
 255
 256         skb = dev_alloc_skb(local->tx_headroom +
 257                             IEEE80211_ENCRYPT_HEADROOM +
 258                             IEEE80211_ENCRYPT_TAILROOM +
 259                             hdr_len +
 260                             2 + 15 /* PERR IE */);
 261         if (!skb)
 262                 return -1;
 263         skb_reserve(skb, local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM);
 264         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 265         memset(mgmt, 0, hdr_len);
 266         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 267                                           IEEE80211_STYPE_ACTION);
 268
 269         memcpy(mgmt->da, ra, ETH_ALEN);
 270         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 271         /* BSSID == SA */
 272         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 273         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 274         mgmt->u.action.u.mesh_action.action_code =
 275                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 276         ie_len = 15;
 277         pos = skb_put(skb, 2 + ie_len);
 278         *pos++ = WLAN_EID_PERR;
 279         *pos++ = ie_len;
 280         /* ttl */
 281         *pos++ = ttl;
 282         /* number of destinations */
 283         *pos++ = 1;
 284         /*
 285          * flags bit, bit 1 is unset if we know the sequence number and
 286          * bit 2 is set if we have a reason code
 287          */
 288         *pos = 0;
 289         if (!target_sn)
 290                 *pos |= MP_F_USN;
 291         if (target_rcode)
 292                 *pos |= MP_F_RCODE;
 293         pos++;
 294         memcpy(pos, target, ETH_ALEN);
 295         pos += ETH_ALEN;
 296         memcpy(pos, &target_sn, 4);
 297         pos += 4;
 298         memcpy(pos, &target_rcode, 2);
 299
 300         /* see note in function header */
 301         prepare_frame_for_deferred_tx(sdata, skb);
 302         ifmsh->next_perr = TU_TO_EXP_TIME(
 303                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 304         ieee80211_add_pending_skb(local, skb);
 305         return 0;
 306 }
 307
 308 void ieee80211s_update_metric(struct ieee80211_local *local,
 309                 struct sta_info *sta, struct sk_buff *skb)
 310 {
 311         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 312         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 313         int failed;
 314
 315         if (!ieee80211_is_data(hdr->frame_control))
 316                 return;
 317
 318         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 319
 320         /* moving average, scaled to 100 */
 321         sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
 322         if (sta->fail_avg > 95)
 323                 mesh_plink_broken(sta);
 324 }
 325
 326 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 327                                    struct sta_info *sta)
 328 {
 329         struct rate_info rinfo;
 330         /* This should be adjusted for each device */
 331         int device_constant = 1 << ARITH_SHIFT;
 332         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 333         int s_unit = 1 << ARITH_SHIFT;
 334         int rate, err;
 335         u32 tx_time, estimated_retx;
 336         u64 result;
 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  * @action: type of hwmp ie
 364  *
 365  * This function updates the path routing information to the originator and the
 366  * transmitter of a HWMP PREQ or PREP frame.
 367  *
 368  * Returns: metric to frame originator or 0 if the frame should not be further
 369  * processed
 370  *
 371  * Notes: this function is the only place (besides user-provided info) where
 372  * path routing information is updated.
 373  */
 374 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 375                                struct ieee80211_mgmt *mgmt,
 376                                const u8 *hwmp_ie, enum mpath_frame_type action)
 377 {
 378         struct ieee80211_local *local = sdata->local;
 379         struct mesh_path *mpath;
 380         struct sta_info *sta;
 381         bool fresh_info;
 382         const u8 *orig_addr, *ta;
 383         u32 orig_sn, orig_metric;
 384         unsigned long orig_lifetime, exp_time;
 385         u32 last_hop_metric, new_metric;
 386         bool process = true;
 387
 388         rcu_read_lock();
 389         sta = sta_info_get(sdata, mgmt->sa);
 390         if (!sta) {
 391                 rcu_read_unlock();
 392                 return 0;
 393         }
 394
 395         last_hop_metric = airtime_link_metric_get(local, sta);
 396         /* Update and check originator routing info */
 397         fresh_info = true;
 398
 399         switch (action) {
 400         case MPATH_PREQ:
 401                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 402                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 403                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 404                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 405                 break;
 406         case MPATH_PREP:
 407                 /* Originator here refers to the MP that was the target in the
 408                  * Path Request. We divert from the nomenclature in the draft
 409                  * so that we can easily use a single function to gather path
 410                  * information from both PREQ and PREP frames.
 411                  */
 412                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 413                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 414                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 415                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 416                 break;
 417         default:
 418                 rcu_read_unlock();
 419                 return 0;
 420         }
 421         new_metric = orig_metric + last_hop_metric;
 422         if (new_metric < orig_metric)
 423                 new_metric = MAX_METRIC;
 424         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 425
 426         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 427                 /* This MP is the originator, we are not interested in this
 428                  * frame, except for updating transmitter's path info.
 429                  */
 430                 process = false;
 431                 fresh_info = false;
 432         } else {
 433                 mpath = mesh_path_lookup(sdata, orig_addr);
 434                 if (mpath) {
 435                         spin_lock_bh(&mpath->state_lock);
 436                         if (mpath->flags & MESH_PATH_FIXED)
 437                                 fresh_info = false;
 438                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 439                             (mpath->flags & MESH_PATH_SN_VALID)) {
 440                                 if (SN_GT(mpath->sn, orig_sn) ||
 441                                     (mpath->sn == orig_sn &&
 442                                      new_metric >= mpath->metric)) {
 443                                         process = false;
 444                                         fresh_info = false;
 445                                 }
 446                         }
 447                 } else {
 448                         mesh_path_add(sdata, orig_addr);
 449                         mpath = mesh_path_lookup(sdata, orig_addr);
 450                         if (!mpath) {
 451                                 rcu_read_unlock();
 452                                 return 0;
 453                         }
 454                         spin_lock_bh(&mpath->state_lock);
 455                 }
 456
 457                 if (fresh_info) {
 458                         mesh_path_assign_nexthop(mpath, sta);
 459                         mpath->flags |= MESH_PATH_SN_VALID;
 460                         mpath->metric = new_metric;
 461                         mpath->sn = orig_sn;
 462                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 463                                           ?  mpath->exp_time : exp_time;
 464                         mesh_path_activate(mpath);
 465                         spin_unlock_bh(&mpath->state_lock);
 466                         mesh_path_tx_pending(mpath);
 467                         /* draft says preq_id should be saved to, but there does
 468                          * not seem to be any use for it, skipping by now
 469                          */
 470                 } else
 471                         spin_unlock_bh(&mpath->state_lock);
 472         }
 473
 474         /* Update and check transmitter routing info */
 475         ta = mgmt->sa;
 476         if (ether_addr_equal(orig_addr, ta))
 477                 fresh_info = false;
 478         else {
 479                 fresh_info = true;
 480
 481                 mpath = mesh_path_lookup(sdata, ta);
 482                 if (mpath) {
 483                         spin_lock_bh(&mpath->state_lock);
 484                         if ((mpath->flags & MESH_PATH_FIXED) ||
 485                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 486                                         (last_hop_metric > mpath->metric)))
 487                                 fresh_info = false;
 488                 } else {
 489                         mesh_path_add(sdata, ta);
 490                         mpath = mesh_path_lookup(sdata, ta);
 491                         if (!mpath) {
 492                                 rcu_read_unlock();
 493                                 return 0;
 494                         }
 495                         spin_lock_bh(&mpath->state_lock);
 496                 }
 497
 498                 if (fresh_info) {
 499                         mesh_path_assign_nexthop(mpath, sta);
 500                         mpath->metric = last_hop_metric;
 501                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 502                                           ?  mpath->exp_time : exp_time;
 503                         mesh_path_activate(mpath);
 504                         spin_unlock_bh(&mpath->state_lock);
 505                         mesh_path_tx_pending(mpath);
 506                 } else
 507                         spin_unlock_bh(&mpath->state_lock);
 508         }
 509
 510         rcu_read_unlock();
 511
 512         return process ? new_metric : 0;
 513 }
 514
 515 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 516                                     struct ieee80211_mgmt *mgmt,
 517                                     const u8 *preq_elem, u32 metric)
 518 {
 519         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 520         struct mesh_path *mpath = NULL;
 521         const u8 *target_addr, *orig_addr;
 522         const u8 *da;
 523         u8 target_flags, ttl, flags;
 524         u32 orig_sn, target_sn, lifetime, orig_metric;
 525         bool reply = false;
 526         bool forward = true;
 527         bool root_is_gate;
 528
 529         /* Update target SN, if present */
 530         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 531         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 532         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 533         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 534         target_flags = PREQ_IE_TARGET_F(preq_elem);
 535         orig_metric = metric;
 536         /* Proactive PREQ gate announcements */
 537         flags = PREQ_IE_FLAGS(preq_elem);
 538         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 539
 540         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 541
 542         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 543                 mhwmp_dbg(sdata, "PREQ is for us\n");
 544                 forward = false;
 545                 reply = true;
 546                 metric = 0;
 547                 if (time_after(jiffies, ifmsh->last_sn_update +
 548                                         net_traversal_jiffies(sdata)) ||
 549                     time_before(jiffies, ifmsh->last_sn_update)) {
 550                         target_sn = ++ifmsh->sn;
 551                         ifmsh->last_sn_update = jiffies;
 552                 }
 553         } else if (is_broadcast_ether_addr(target_addr) &&
 554                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 555                 rcu_read_lock();
 556                 mpath = mesh_path_lookup(sdata, orig_addr);
 557                 if (mpath) {
 558                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 559                                 reply = true;
 560                                 target_addr = sdata->vif.addr;
 561                                 target_sn = ++ifmsh->sn;
 562                                 metric = 0;
 563                                 ifmsh->last_sn_update = jiffies;
 564                         }
 565                         if (root_is_gate)
 566                                 mesh_path_add_gate(mpath);
 567                 }
 568                 rcu_read_unlock();
 569         } else {
 570                 rcu_read_lock();
 571                 mpath = mesh_path_lookup(sdata, target_addr);
 572                 if (mpath) {
 573                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 574                                         SN_LT(mpath->sn, target_sn)) {
 575                                 mpath->sn = target_sn;
 576                                 mpath->flags |= MESH_PATH_SN_VALID;
 577                         } else if ((!(target_flags & MP_F_DO)) &&
 578                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 579                                 reply = true;
 580                                 metric = mpath->metric;
 581                                 target_sn = mpath->sn;
 582                                 if (target_flags & MP_F_RF)
 583                                         target_flags |= MP_F_DO;
 584                                 else
 585                                         forward = false;
 586                         }
 587                 }
 588                 rcu_read_unlock();
 589         }
 590
 591         if (reply) {
 592                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 593                 ttl = ifmsh->mshcfg.element_ttl;
 594                 if (ttl != 0) {
 595                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 596                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 597                                 cpu_to_le32(orig_sn), 0, target_addr,
 598                                 cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 599                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 600                                 0, sdata);
 601                 } else {
 602                         ifmsh->mshstats.dropped_frames_ttl++;
 603                 }
 604         }
 605
 606         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 607                 u32 preq_id;
 608                 u8 hopcount;
 609
 610                 ttl = PREQ_IE_TTL(preq_elem);
 611                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 612                 if (ttl <= 1) {
 613                         ifmsh->mshstats.dropped_frames_ttl++;
 614                         return;
 615                 }
 616                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 617                 --ttl;
 618                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 619                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 620                 da = (mpath && mpath->is_root) ?
 621                         mpath->rann_snd_addr : broadcast_addr;
 622
 623                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 624                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 625                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 626                         metric = orig_metric;
 627                 }
 628
 629                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 630                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 631                                 cpu_to_le32(target_sn), da,
 632                                 hopcount, ttl, cpu_to_le32(lifetime),
 633                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 634                                 sdata);
 635                 if (!is_multicast_ether_addr(da))
 636                         ifmsh->mshstats.fwded_unicast++;
 637                 else
 638                         ifmsh->mshstats.fwded_mcast++;
 639                 ifmsh->mshstats.fwded_frames++;
 640         }
 641 }
 642
 643
 644 static inline struct sta_info *
 645 next_hop_deref_protected(struct mesh_path *mpath)
 646 {
 647         return rcu_dereference_protected(mpath->next_hop,
 648                                          lockdep_is_held(&mpath->state_lock));
 649 }
 650
 651
 652 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 653                                     struct ieee80211_mgmt *mgmt,
 654                                     const u8 *prep_elem, u32 metric)
 655 {
 656         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 657         struct mesh_path *mpath;
 658         const u8 *target_addr, *orig_addr;
 659         u8 ttl, hopcount, flags;
 660         u8 next_hop[ETH_ALEN];
 661         u32 target_sn, orig_sn, lifetime;
 662
 663         mhwmp_dbg(sdata, "received PREP from %pM\n",
 664                   PREP_IE_ORIG_ADDR(prep_elem));
 665
 666         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 667         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 668                 /* destination, no forwarding required */
 669                 return;
 670
 671         if (!ifmsh->mshcfg.dot11MeshForwarding)
 672                 return;
 673
 674         ttl = PREP_IE_TTL(prep_elem);
 675         if (ttl <= 1) {
 676                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 677                 return;
 678         }
 679
 680         rcu_read_lock();
 681         mpath = mesh_path_lookup(sdata, orig_addr);
 682         if (mpath)
 683                 spin_lock_bh(&mpath->state_lock);
 684         else
 685                 goto fail;
 686         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 687                 spin_unlock_bh(&mpath->state_lock);
 688                 goto fail;
 689         }
 690         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 691         spin_unlock_bh(&mpath->state_lock);
 692         --ttl;
 693         flags = PREP_IE_FLAGS(prep_elem);
 694         lifetime = PREP_IE_LIFETIME(prep_elem);
 695         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 696         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 697         target_sn = PREP_IE_TARGET_SN(prep_elem);
 698         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 699
 700         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 701                 cpu_to_le32(orig_sn), 0, target_addr,
 702                 cpu_to_le32(target_sn), next_hop, hopcount,
 703                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 704                 0, sdata);
 705         rcu_read_unlock();
 706
 707         sdata->u.mesh.mshstats.fwded_unicast++;
 708         sdata->u.mesh.mshstats.fwded_frames++;
 709         return;
 710
 711 fail:
 712         rcu_read_unlock();
 713         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 714 }
 715
 716 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 717                                     struct ieee80211_mgmt *mgmt,
 718                                     const u8 *perr_elem)
 719 {
 720         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 721         struct mesh_path *mpath;
 722         u8 ttl;
 723         const u8 *ta, *target_addr;
 724         u32 target_sn;
 725         u16 target_rcode;
 726
 727         ta = mgmt->sa;
 728         ttl = PERR_IE_TTL(perr_elem);
 729         if (ttl <= 1) {
 730                 ifmsh->mshstats.dropped_frames_ttl++;
 731                 return;
 732         }
 733         ttl--;
 734         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 735         target_sn = PERR_IE_TARGET_SN(perr_elem);
 736         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 737
 738         rcu_read_lock();
 739         mpath = mesh_path_lookup(sdata, target_addr);
 740         if (mpath) {
 741                 struct sta_info *sta;
 742
 743                 spin_lock_bh(&mpath->state_lock);
 744                 sta = next_hop_deref_protected(mpath);
 745                 if (mpath->flags & MESH_PATH_ACTIVE &&
 746                     ether_addr_equal(ta, sta->sta.addr) &&
 747                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 748                     SN_GT(target_sn, mpath->sn))) {
 749                         mpath->flags &= ~MESH_PATH_ACTIVE;
 750                         mpath->sn = target_sn;
 751                         spin_unlock_bh(&mpath->state_lock);
 752                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 753                                 goto endperr;
 754                         mesh_path_error_tx(sdata, ttl, target_addr,
 755                                            cpu_to_le32(target_sn),
 756                                            cpu_to_le16(target_rcode),
 757                                            broadcast_addr);
 758                 } else
 759                         spin_unlock_bh(&mpath->state_lock);
 760         }
 761 endperr:
 762         rcu_read_unlock();
 763 }
 764
 765 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 766                                     struct ieee80211_mgmt *mgmt,
 767                                     const struct ieee80211_rann_ie *rann)
 768 {
 769         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 770         struct ieee80211_local *local = sdata->local;
 771         struct sta_info *sta;
 772         struct mesh_path *mpath;
 773         u8 ttl, flags, hopcount;
 774         const u8 *orig_addr;
 775         u32 orig_sn, metric, metric_txsta, interval;
 776         bool root_is_gate;
 777
 778         ttl = rann->rann_ttl;
 779         flags = rann->rann_flags;
 780         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 781         orig_addr = rann->rann_addr;
 782         orig_sn = le32_to_cpu(rann->rann_seq);
 783         interval = le32_to_cpu(rann->rann_interval);
 784         hopcount = rann->rann_hopcount;
 785         hopcount++;
 786         metric = le32_to_cpu(rann->rann_metric);
 787
 788         /*  Ignore our own RANNs */
 789         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 790                 return;
 791
 792         mhwmp_dbg(sdata,
 793                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 794                   orig_addr, mgmt->sa, root_is_gate);
 795
 796         rcu_read_lock();
 797         sta = sta_info_get(sdata, mgmt->sa);
 798         if (!sta) {
 799                 rcu_read_unlock();
 800                 return;
 801         }
 802
 803         metric_txsta = airtime_link_metric_get(local, sta);
 804
 805         mpath = mesh_path_lookup(sdata, orig_addr);
 806         if (!mpath) {
 807                 mesh_path_add(sdata, orig_addr);
 808                 mpath = mesh_path_lookup(sdata, orig_addr);
 809                 if (!mpath) {
 810                         rcu_read_unlock();
 811                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 812                         return;
 813                 }
 814         }
 815
 816         if (!(SN_LT(mpath->sn, orig_sn)) &&
 817             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 818                 rcu_read_unlock();
 819                 return;
 820         }
 821
 822         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 823              (time_after(jiffies, mpath->last_preq_to_root +
 824                                   root_path_confirmation_jiffies(sdata)) ||
 825              time_before(jiffies, mpath->last_preq_to_root))) &&
 826              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 827                 mhwmp_dbg(sdata,
 828                           "time to refresh root mpath %pM\n",
 829                           orig_addr);
 830                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 831                 mpath->last_preq_to_root = jiffies;
 832         }
 833
 834         mpath->sn = orig_sn;
 835         mpath->rann_metric = metric + metric_txsta;
 836         mpath->is_root = true;
 837         /* Recording RANNs sender address to send individually
 838          * addressed PREQs destined for root mesh STA */
 839         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 840
 841         if (root_is_gate)
 842                 mesh_path_add_gate(mpath);
 843
 844         if (ttl <= 1) {
 845                 ifmsh->mshstats.dropped_frames_ttl++;
 846                 rcu_read_unlock();
 847                 return;
 848         }
 849         ttl--;
 850
 851         if (ifmsh->mshcfg.dot11MeshForwarding) {
 852                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 853                                        cpu_to_le32(orig_sn),
 854                                        0, NULL, 0, broadcast_addr,
 855                                        hopcount, ttl, cpu_to_le32(interval),
 856                                        cpu_to_le32(metric + metric_txsta),
 857                                        0, sdata);
 858         }
 859
 860         rcu_read_unlock();
 861 }
 862
 863
 864 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 865                             struct ieee80211_mgmt *mgmt, size_t len)
 866 {
 867         struct ieee802_11_elems elems;
 868         size_t baselen;
 869         u32 last_hop_metric;
 870         struct sta_info *sta;
 871
 872         /* need action_code */
 873         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 874                 return;
 875
 876         rcu_read_lock();
 877         sta = sta_info_get(sdata, mgmt->sa);
 878         if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 879                 rcu_read_unlock();
 880                 return;
 881         }
 882         rcu_read_unlock();
 883
 884         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 885         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 886                         len - baselen, &elems);
 887
 888         if (elems.preq) {
 889                 if (elems.preq_len != 37)
 890                         /* Right now we support just 1 destination and no AE */
 891                         return;
 892                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 893                                                       MPATH_PREQ);
 894                 if (last_hop_metric)
 895                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 896                                                 last_hop_metric);
 897         }
 898         if (elems.prep) {
 899                 if (elems.prep_len != 31)
 900                         /* Right now we support no AE */
 901                         return;
 902                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 903                                                       MPATH_PREP);
 904                 if (last_hop_metric)
 905                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 906                                                 last_hop_metric);
 907         }
 908         if (elems.perr) {
 909                 if (elems.perr_len != 15)
 910                         /* Right now we support only one destination per PERR */
 911                         return;
 912                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 913         }
 914         if (elems.rann)
 915                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 916 }
 917
 918 /**
 919  * mesh_queue_preq - queue a PREQ to a given destination
 920  *
 921  * @mpath: mesh path to discover
 922  * @flags: special attributes of the PREQ to be sent
 923  *
 924  * Locking: the function must be called from within a rcu read lock block.
 925  *
 926  */
 927 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 928 {
 929         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 930         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 931         struct mesh_preq_queue *preq_node;
 932
 933         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 934         if (!preq_node) {
 935                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 936                 return;
 937         }
 938
 939         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 940         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 941                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 942                 kfree(preq_node);
 943                 if (printk_ratelimit())
 944                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 945                 return;
 946         }
 947
 948         spin_lock(&mpath->state_lock);
 949         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 950                 spin_unlock(&mpath->state_lock);
 951                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 952                 kfree(preq_node);
 953                 return;
 954         }
 955
 956         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 957         preq_node->flags = flags;
 958
 959         mpath->flags |= MESH_PATH_REQ_QUEUED;
 960         spin_unlock(&mpath->state_lock);
 961
 962         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 963         ++ifmsh->preq_queue_len;
 964         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 965
 966         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 967                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 968
 969         else if (time_before(jiffies, ifmsh->last_preq)) {
 970                 /* avoid long wait if did not send preqs for a long time
 971                  * and jiffies wrapped around
 972                  */
 973                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 974                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 975         } else
 976                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 977                                                 min_preq_int_jiff(sdata));
 978 }
 979
 980 /**
 981  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 982  *
 983  * @sdata: local mesh subif
 984  */
 985 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 986 {
 987         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 988         struct mesh_preq_queue *preq_node;
 989         struct mesh_path *mpath;
 990         u8 ttl, target_flags;
 991         const u8 *da;
 992         u32 lifetime;
 993
 994         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 995         if (!ifmsh->preq_queue_len ||
 996                 time_before(jiffies, ifmsh->last_preq +
 997                                 min_preq_int_jiff(sdata))) {
 998                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 999                 return;
1000         }
1001
1002         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1003                         struct mesh_preq_queue, list);
1004         list_del(&preq_node->list);
1005         --ifmsh->preq_queue_len;
1006         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1007
1008         rcu_read_lock();
1009         mpath = mesh_path_lookup(sdata, preq_node->dst);
1010         if (!mpath)
1011                 goto enddiscovery;
1012
1013         spin_lock_bh(&mpath->state_lock);
1014         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1015         if (preq_node->flags & PREQ_Q_F_START) {
1016                 if (mpath->flags & MESH_PATH_RESOLVING) {
1017                         spin_unlock_bh(&mpath->state_lock);
1018                         goto enddiscovery;
1019                 } else {
1020                         mpath->flags &= ~MESH_PATH_RESOLVED;
1021                         mpath->flags |= MESH_PATH_RESOLVING;
1022                         mpath->discovery_retries = 0;
1023                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1024                 }
1025         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1026                         mpath->flags & MESH_PATH_RESOLVED) {
1027                 mpath->flags &= ~MESH_PATH_RESOLVING;
1028                 spin_unlock_bh(&mpath->state_lock);
1029                 goto enddiscovery;
1030         }
1031
1032         ifmsh->last_preq = jiffies;
1033
1034         if (time_after(jiffies, ifmsh->last_sn_update +
1035                                 net_traversal_jiffies(sdata)) ||
1036             time_before(jiffies, ifmsh->last_sn_update)) {
1037                 ++ifmsh->sn;
1038                 sdata->u.mesh.last_sn_update = jiffies;
1039         }
1040         lifetime = default_lifetime(sdata);
1041         ttl = sdata->u.mesh.mshcfg.element_ttl;
1042         if (ttl == 0) {
1043                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1044                 spin_unlock_bh(&mpath->state_lock);
1045                 goto enddiscovery;
1046         }
1047
1048         if (preq_node->flags & PREQ_Q_F_REFRESH)
1049                 target_flags = MP_F_DO;
1050         else
1051                 target_flags = MP_F_RF;
1052
1053         spin_unlock_bh(&mpath->state_lock);
1054         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1055         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1056                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1057                         cpu_to_le32(mpath->sn), da, 0,
1058                         ttl, cpu_to_le32(lifetime), 0,
1059                         cpu_to_le32(ifmsh->preq_id++), sdata);
1060         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1061
1062 enddiscovery:
1063         rcu_read_unlock();
1064         kfree(preq_node);
1065 }
1066
1067 /**
1068  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1069  *
1070  * @skb: 802.11 frame to be sent
1071  * @sdata: network subif the frame will be sent through
1072  *
1073  * Lookup next hop for given skb and start path discovery if no
1074  * forwarding information is found.
1075  *
1076  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1077  * skb is freeed here if no mpath could be allocated.
1078  */
1079 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1080                          struct sk_buff *skb)
1081 {
1082         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1083         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1084         struct mesh_path *mpath;
1085         struct sk_buff *skb_to_free = NULL;
1086         u8 *target_addr = hdr->addr3;
1087         int err = 0;
1088
1089         /* Nulls are only sent to peers for PS and should be pre-addressed */
1090         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1091                 return 0;
1092
1093         rcu_read_lock();
1094         err = mesh_nexthop_lookup(sdata, skb);
1095         if (!err)
1096                 goto endlookup;
1097
1098         /* no nexthop found, start resolving */
1099         mpath = mesh_path_lookup(sdata, target_addr);
1100         if (!mpath) {
1101                 mesh_path_add(sdata, target_addr);
1102                 mpath = mesh_path_lookup(sdata, target_addr);
1103                 if (!mpath) {
1104                         mesh_path_discard_frame(sdata, skb);
1105                         err = -ENOSPC;
1106                         goto endlookup;
1107                 }
1108         }
1109
1110         if (!(mpath->flags & MESH_PATH_RESOLVING))
1111                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1112
1113         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1114                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1115
1116         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1117         ieee80211_set_qos_hdr(sdata, skb);
1118         skb_queue_tail(&mpath->frame_queue, skb);
1119         err = -ENOENT;
1120         if (skb_to_free)
1121                 mesh_path_discard_frame(sdata, skb_to_free);
1122
1123 endlookup:
1124         rcu_read_unlock();
1125         return err;
1126 }
1127
1128 /**
1129  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1130  * this function is considered "using" the associated mpath, so preempt a path
1131  * refresh if this mpath expires soon.
1132  *
1133  * @skb: 802.11 frame to be sent
1134  * @sdata: network subif the frame will be sent through
1135  *
1136  * Returns: 0 if the next hop was found. Nonzero otherwise.
1137  */
1138 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1139                         struct sk_buff *skb)
1140 {
1141         struct mesh_path *mpath;
1142         struct sta_info *next_hop;
1143         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1144         u8 *target_addr = hdr->addr3;
1145         int err = -ENOENT;
1146
1147         rcu_read_lock();
1148         mpath = mesh_path_lookup(sdata, target_addr);
1149
1150         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1151                 goto endlookup;
1152
1153         if (time_after(jiffies,
1154                        mpath->exp_time -
1155                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1156             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1157             !(mpath->flags & MESH_PATH_RESOLVING) &&
1158             !(mpath->flags & MESH_PATH_FIXED))
1159                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1160
1161         next_hop = rcu_dereference(mpath->next_hop);
1162         if (next_hop) {
1163                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1164                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1165                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1166                 err = 0;
1167         }
1168
1169 endlookup:
1170         rcu_read_unlock();
1171         return err;
1172 }
1173
1174 void mesh_path_timer(unsigned long data)
1175 {
1176         struct mesh_path *mpath = (void *) data;
1177         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1178         int ret;
1179
1180         if (sdata->local->quiescing)
1181                 return;
1182
1183         spin_lock_bh(&mpath->state_lock);
1184         if (mpath->flags & MESH_PATH_RESOLVED ||
1185                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1186                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1187                 spin_unlock_bh(&mpath->state_lock);
1188         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1189                 ++mpath->discovery_retries;
1190                 mpath->discovery_timeout *= 2;
1191                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1192                 spin_unlock_bh(&mpath->state_lock);
1193                 mesh_queue_preq(mpath, 0);
1194         } else {
1195                 mpath->flags = 0;
1196                 mpath->exp_time = jiffies;
1197                 spin_unlock_bh(&mpath->state_lock);
1198                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1199                         ret = mesh_path_send_to_gates(mpath);
1200                         if (ret)
1201                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1202                 } else
1203                         mesh_path_flush_pending(mpath);
1204         }
1205 }
1206
1207 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1208 {
1209         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1210         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1211         u8 flags, target_flags = 0;
1212
1213         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1214                         ? RANN_FLAG_IS_GATE : 0;
1215
1216         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1217         case IEEE80211_PROACTIVE_RANN:
1218                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1219                                cpu_to_le32(++ifmsh->sn),
1220                                0, NULL, 0, broadcast_addr,
1221                                0, ifmsh->mshcfg.element_ttl,
1222                                cpu_to_le32(interval), 0, 0, sdata);
1223                 break;
1224         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1225                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1226         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1227                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1228                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1229                                 IEEE80211_PREQ_USN_FLAG;
1230                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1231                                 cpu_to_le32(++ifmsh->sn), target_flags,
1232                                 (u8 *) broadcast_addr, 0, broadcast_addr,
1233                                 0, ifmsh->mshcfg.element_ttl,
1234                                 cpu_to_le32(interval),
1235                                 0, cpu_to_le32(ifmsh->preq_id++), sdata);
1236                 break;
1237         default:
1238                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1239                 return;
1240         }
1241 }