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