net/mac80211/mesh_hwmp.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/etherdevice.h>
  12 #include <asm/unaligned.h>
  13 #include "wme.h"
  14 #include "mesh.h"
  15
  16 #ifdef CONFIG_MAC80211_VERBOSE_MHWMP_DEBUG
  17 #define mhwmp_dbg(fmt, args...) \
  18         pr_debug("Mesh HWMP (%s): " fmt "\n", sdata->name, ##args)
  19 #else
  20 #define mhwmp_dbg(fmt, args...)   do { (void)(0); } while (0)
  21 #endif
  22
  23 #define TEST_FRAME_LEN  8192
  24 #define MAX_METRIC      0xffffffff
  25 #define ARITH_SHIFT     8
  26
  27 /* Number of frames buffered per destination for unresolved destinations */
  28 #define MESH_FRAME_QUEUE_LEN    10
  29 #define MAX_PREQ_QUEUE_LEN      64
  30
  31 /* Destination only */
  32 #define MP_F_DO 0x1
  33 /* Reply and forward */
  34 #define MP_F_RF 0x2
  35 /* Unknown Sequence Number */
  36 #define MP_F_USN    0x01
  37 /* Reason code Present */
  38 #define MP_F_RCODE  0x02
  39
  40 static void mesh_queue_preq(struct mesh_path *, u8);
  41
  42 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
  43 {
  44         if (ae)
  45                 offset += 6;
  46         return get_unaligned_le32(preq_elem + offset);
  47 }
  48
  49 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
  50 {
  51         if (ae)
  52                 offset += 6;
  53         return get_unaligned_le16(preq_elem + offset);
  54 }
  55
  56 /* HWMP IE processing macros */
  57 #define AE_F                    (1<<6)
  58 #define AE_F_SET(x)             (*x & AE_F)
  59 #define PREQ_IE_FLAGS(x)        (*(x))
  60 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  61 #define PREQ_IE_TTL(x)          (*(x + 2))
  62 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  63 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  64 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  65 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  66 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  67 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  68 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  69 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  70
  71
  72 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  73 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  74 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  75 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  76 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  77 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  78 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  79 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  80 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  81
  82 #define PERR_IE_TTL(x)          (*(x))
  83 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  84 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  85 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  86 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  87
  88 #define MSEC_TO_TU(x) (x*1000/1024)
  89 #define SN_GT(x, y) ((s32)(y - x) < 0)
  90 #define SN_LT(x, y) ((s32)(x - y) < 0)
  91
  92 #define net_traversal_jiffies(s) \
  93         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  94 #define default_lifetime(s) \
  95         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  96 #define min_preq_int_jiff(s) \
  97         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  98 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  99 #define disc_timeout_jiff(s) \
 100         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
 101 #define root_path_confirmation_jiffies(s) \
 102         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
 103
 104 enum mpath_frame_type {
 105         MPATH_PREQ = 0,
 106         MPATH_PREP,
 107         MPATH_PERR,
 108         MPATH_RANN
 109 };
 110
 111 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 112
 113 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 114                 u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
 115                 __le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
 116                 __le32 lifetime, __le32 metric, __le32 preq_id,
 117                 struct ieee80211_sub_if_data *sdata)
 118 {
 119         struct ieee80211_local *local = sdata->local;
 120         struct sk_buff *skb;
 121         struct ieee80211_mgmt *mgmt;
 122         u8 *pos, ie_len;
 123         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 124                       sizeof(mgmt->u.action.u.mesh_action);
 125
 126         skb = dev_alloc_skb(local->tx_headroom +
 127                             hdr_len +
 128                             2 + 37); /* max HWMP IE */
 129         if (!skb)
 130                 return -1;
 131         skb_reserve(skb, local->tx_headroom);
 132         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 133         memset(mgmt, 0, hdr_len);
 134         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 135                                           IEEE80211_STYPE_ACTION);
 136
 137         memcpy(mgmt->da, da, ETH_ALEN);
 138         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 139         /* BSSID == SA */
 140         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 141         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 142         mgmt->u.action.u.mesh_action.action_code =
 143                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 144
 145         switch (action) {
 146         case MPATH_PREQ:
 147                 mhwmp_dbg("sending PREQ to %pM", target);
 148                 ie_len = 37;
 149                 pos = skb_put(skb, 2 + ie_len);
 150                 *pos++ = WLAN_EID_PREQ;
 151                 break;
 152         case MPATH_PREP:
 153                 mhwmp_dbg("sending PREP to %pM", target);
 154                 ie_len = 31;
 155                 pos = skb_put(skb, 2 + ie_len);
 156                 *pos++ = WLAN_EID_PREP;
 157                 break;
 158         case MPATH_RANN:
 159                 mhwmp_dbg("sending RANN from %pM", orig_addr);
 160                 ie_len = sizeof(struct ieee80211_rann_ie);
 161                 pos = skb_put(skb, 2 + ie_len);
 162                 *pos++ = WLAN_EID_RANN;
 163                 break;
 164         default:
 165                 kfree_skb(skb);
 166                 return -ENOTSUPP;
 167                 break;
 168         }
 169         *pos++ = ie_len;
 170         *pos++ = flags;
 171         *pos++ = hop_count;
 172         *pos++ = ttl;
 173         if (action == MPATH_PREP) {
 174                 memcpy(pos, target, ETH_ALEN);
 175                 pos += ETH_ALEN;
 176                 memcpy(pos, &target_sn, 4);
 177                 pos += 4;
 178         } else {
 179                 if (action == MPATH_PREQ) {
 180                         memcpy(pos, &preq_id, 4);
 181                         pos += 4;
 182                 }
 183                 memcpy(pos, orig_addr, ETH_ALEN);
 184                 pos += ETH_ALEN;
 185                 memcpy(pos, &orig_sn, 4);
 186                 pos += 4;
 187         }
 188         memcpy(pos, &lifetime, 4);      /* interval for RANN */
 189         pos += 4;
 190         memcpy(pos, &metric, 4);
 191         pos += 4;
 192         if (action == MPATH_PREQ) {
 193                 *pos++ = 1; /* destination count */
 194                 *pos++ = target_flags;
 195                 memcpy(pos, target, ETH_ALEN);
 196                 pos += ETH_ALEN;
 197                 memcpy(pos, &target_sn, 4);
 198                 pos += 4;
 199         } else if (action == MPATH_PREP) {
 200                 memcpy(pos, orig_addr, ETH_ALEN);
 201                 pos += ETH_ALEN;
 202                 memcpy(pos, &orig_sn, 4);
 203                 pos += 4;
 204         }
 205
 206         ieee80211_tx_skb(sdata, skb);
 207         return 0;
 208 }
 209
 210
 211 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 212  *  headroom in case the frame is encrypted. */
 213 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 214                 struct sk_buff *skb)
 215 {
 216         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 217
 218         skb_set_mac_header(skb, 0);
 219         skb_set_network_header(skb, 0);
 220         skb_set_transport_header(skb, 0);
 221
 222         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 223         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 224         skb->priority = 7;
 225
 226         info->control.vif = &sdata->vif;
 227         ieee80211_set_qos_hdr(sdata, skb);
 228 }
 229
 230 /**
 231  * mesh_send_path error - Sends a PERR mesh management frame
 232  *
 233  * @target: broken destination
 234  * @target_sn: SN of the broken destination
 235  * @target_rcode: reason code for this PERR
 236  * @ra: node this frame is addressed to
 237  *
 238  * Note: This function may be called with driver locks taken that the driver
 239  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 240  * frame directly but add it to the pending queue instead.
 241  */
 242 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 243                        __le16 target_rcode, const u8 *ra,
 244                        struct ieee80211_sub_if_data *sdata)
 245 {
 246         struct ieee80211_local *local = sdata->local;
 247         struct sk_buff *skb;
 248         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 249         struct ieee80211_mgmt *mgmt;
 250         u8 *pos, ie_len;
 251         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 252                       sizeof(mgmt->u.action.u.mesh_action);
 253
 254         if (time_before(jiffies, ifmsh->next_perr))
 255                 return -EAGAIN;
 256
 257         skb = dev_alloc_skb(local->tx_headroom +
 258                             hdr_len +
 259                             2 + 15 /* PERR IE */);
 260         if (!skb)
 261                 return -1;
 262         skb_reserve(skb, local->tx_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         memcpy(pos, &target_sn, 4);
 296         pos += 4;
 297         memcpy(pos, &target_rcode, 2);
 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  *
 363  * This function updates the path routing information to the originator and the
 364  * transmitter of a HWMP PREQ or PREP frame.
 365  *
 366  * Returns: metric to frame originator or 0 if the frame should not be further
 367  * processed
 368  *
 369  * Notes: this function is the only place (besides user-provided info) where
 370  * path routing information is updated.
 371  */
 372 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 373                             struct ieee80211_mgmt *mgmt,
 374                             u8 *hwmp_ie, enum mpath_frame_type action)
 375 {
 376         struct ieee80211_local *local = sdata->local;
 377         struct mesh_path *mpath;
 378         struct sta_info *sta;
 379         bool fresh_info;
 380         u8 *orig_addr, *ta;
 381         u32 orig_sn, orig_metric;
 382         unsigned long orig_lifetime, exp_time;
 383         u32 last_hop_metric, new_metric;
 384         bool process = true;
 385
 386         rcu_read_lock();
 387         sta = sta_info_get(sdata, mgmt->sa);
 388         if (!sta) {
 389                 rcu_read_unlock();
 390                 return 0;
 391         }
 392
 393         last_hop_metric = airtime_link_metric_get(local, sta);
 394         /* Update and check originator routing info */
 395         fresh_info = true;
 396
 397         switch (action) {
 398         case MPATH_PREQ:
 399                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 400                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 401                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 402                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 403                 break;
 404         case MPATH_PREP:
 405                 /* Originator here refers to the MP that was the target in the
 406                  * Path Request. We divert from the nomenclature in the draft
 407                  * so that we can easily use a single function to gather path
 408                  * information from both PREQ and PREP frames.
 409                  */
 410                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 411                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 412                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 413                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 414                 break;
 415         default:
 416                 rcu_read_unlock();
 417                 return 0;
 418         }
 419         new_metric = orig_metric + last_hop_metric;
 420         if (new_metric < orig_metric)
 421                 new_metric = MAX_METRIC;
 422         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 423
 424         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 425                 /* This MP is the originator, we are not interested in this
 426                  * frame, except for updating transmitter's path info.
 427                  */
 428                 process = false;
 429                 fresh_info = false;
 430         } else {
 431                 mpath = mesh_path_lookup(orig_addr, sdata);
 432                 if (mpath) {
 433                         spin_lock_bh(&mpath->state_lock);
 434                         if (mpath->flags & MESH_PATH_FIXED)
 435                                 fresh_info = false;
 436                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 437                             (mpath->flags & MESH_PATH_SN_VALID)) {
 438                                 if (SN_GT(mpath->sn, orig_sn) ||
 439                                     (mpath->sn == orig_sn &&
 440                                      new_metric >= mpath->metric)) {
 441                                         process = false;
 442                                         fresh_info = false;
 443                                 }
 444                         }
 445                 } else {
 446                         mesh_path_add(orig_addr, sdata);
 447                         mpath = mesh_path_lookup(orig_addr, sdata);
 448                         if (!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(ta, sdata);
 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                         mesh_path_add(ta, sdata);
 488                         mpath = mesh_path_lookup(ta, sdata);
 489                         if (!mpath) {
 490                                 rcu_read_unlock();
 491                                 return 0;
 492                         }
 493                         spin_lock_bh(&mpath->state_lock);
 494                 }
 495
 496                 if (fresh_info) {
 497                         mesh_path_assign_nexthop(mpath, sta);
 498                         mpath->metric = last_hop_metric;
 499                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 500                                           ?  mpath->exp_time : exp_time;
 501                         mesh_path_activate(mpath);
 502                         spin_unlock_bh(&mpath->state_lock);
 503                         mesh_path_tx_pending(mpath);
 504                 } else
 505                         spin_unlock_bh(&mpath->state_lock);
 506         }
 507
 508         rcu_read_unlock();
 509
 510         return process ? new_metric : 0;
 511 }
 512
 513 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 514                                     struct ieee80211_mgmt *mgmt,
 515                                     u8 *preq_elem, u32 metric)
 516 {
 517         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 518         struct mesh_path *mpath = NULL;
 519         u8 *target_addr, *orig_addr;
 520         const u8 *da;
 521         u8 target_flags, ttl, flags;
 522         u32 orig_sn, target_sn, lifetime, orig_metric;
 523         bool reply = false;
 524         bool forward = true;
 525         bool root_is_gate;
 526
 527         /* Update target SN, if present */
 528         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 529         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 530         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 531         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 532         target_flags = PREQ_IE_TARGET_F(preq_elem);
 533         orig_metric = metric;
 534         /* Proactive PREQ gate announcements */
 535         flags = PREQ_IE_FLAGS(preq_elem);
 536         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 537
 538         mhwmp_dbg("received PREQ from %pM", orig_addr);
 539
 540         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 541                 mhwmp_dbg("PREQ is for us");
 542                 forward = false;
 543                 reply = true;
 544                 metric = 0;
 545                 if (time_after(jiffies, ifmsh->last_sn_update +
 546                                         net_traversal_jiffies(sdata)) ||
 547                     time_before(jiffies, ifmsh->last_sn_update)) {
 548                         target_sn = ++ifmsh->sn;
 549                         ifmsh->last_sn_update = jiffies;
 550                 }
 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(orig_addr, sdata);
 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(target_addr, sdata);
 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("replying to the PREQ");
 594                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 595                                 cpu_to_le32(orig_sn), 0, target_addr,
 596                                 cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 597                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 598                                 0, sdata);
 599                 } else {
 600                         ifmsh->mshstats.dropped_frames_ttl++;
 601                 }
 602         }
 603
 604         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 605                 u32 preq_id;
 606                 u8 hopcount;
 607
 608                 ttl = PREQ_IE_TTL(preq_elem);
 609                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 610                 if (ttl <= 1) {
 611                         ifmsh->mshstats.dropped_frames_ttl++;
 612                         return;
 613                 }
 614                 mhwmp_dbg("forwarding the PREQ from %pM", orig_addr);
 615                 --ttl;
 616                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 617                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 618                 da = (mpath && mpath->is_root) ?
 619                         mpath->rann_snd_addr : broadcast_addr;
 620
 621                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 622                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 623                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 624                         metric = orig_metric;
 625                 }
 626
 627                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 628                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 629                                 cpu_to_le32(target_sn), da,
 630                                 hopcount, ttl, cpu_to_le32(lifetime),
 631                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 632                                 sdata);
 633                 if (!is_multicast_ether_addr(da))
 634                         ifmsh->mshstats.fwded_unicast++;
 635                 else
 636                         ifmsh->mshstats.fwded_mcast++;
 637                 ifmsh->mshstats.fwded_frames++;
 638         }
 639 }
 640
 641
 642 static inline struct sta_info *
 643 next_hop_deref_protected(struct mesh_path *mpath)
 644 {
 645         return rcu_dereference_protected(mpath->next_hop,
 646                                          lockdep_is_held(&mpath->state_lock));
 647 }
 648
 649
 650 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 651                                     struct ieee80211_mgmt *mgmt,
 652                                     u8 *prep_elem, u32 metric)
 653 {
 654         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 655         struct mesh_path *mpath;
 656         u8 *target_addr, *orig_addr;
 657         u8 ttl, hopcount, flags;
 658         u8 next_hop[ETH_ALEN];
 659         u32 target_sn, orig_sn, lifetime;
 660
 661         mhwmp_dbg("received PREP from %pM", PREP_IE_ORIG_ADDR(prep_elem));
 662
 663         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 664         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 665                 /* destination, no forwarding required */
 666                 return;
 667
 668         if (!ifmsh->mshcfg.dot11MeshForwarding)
 669                 return;
 670
 671         ttl = PREP_IE_TTL(prep_elem);
 672         if (ttl <= 1) {
 673                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 674                 return;
 675         }
 676
 677         rcu_read_lock();
 678         mpath = mesh_path_lookup(orig_addr, sdata);
 679         if (mpath)
 680                 spin_lock_bh(&mpath->state_lock);
 681         else
 682                 goto fail;
 683         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 684                 spin_unlock_bh(&mpath->state_lock);
 685                 goto fail;
 686         }
 687         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 688         spin_unlock_bh(&mpath->state_lock);
 689         --ttl;
 690         flags = PREP_IE_FLAGS(prep_elem);
 691         lifetime = PREP_IE_LIFETIME(prep_elem);
 692         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 693         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 694         target_sn = PREP_IE_TARGET_SN(prep_elem);
 695         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 696
 697         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 698                 cpu_to_le32(orig_sn), 0, target_addr,
 699                 cpu_to_le32(target_sn), next_hop, hopcount,
 700                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 701                 0, sdata);
 702         rcu_read_unlock();
 703
 704         sdata->u.mesh.mshstats.fwded_unicast++;
 705         sdata->u.mesh.mshstats.fwded_frames++;
 706         return;
 707
 708 fail:
 709         rcu_read_unlock();
 710         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 711 }
 712
 713 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 714                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 715 {
 716         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 717         struct mesh_path *mpath;
 718         u8 ttl;
 719         u8 *ta, *target_addr;
 720         u32 target_sn;
 721         u16 target_rcode;
 722
 723         ta = mgmt->sa;
 724         ttl = PERR_IE_TTL(perr_elem);
 725         if (ttl <= 1) {
 726                 ifmsh->mshstats.dropped_frames_ttl++;
 727                 return;
 728         }
 729         ttl--;
 730         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 731         target_sn = PERR_IE_TARGET_SN(perr_elem);
 732         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 733
 734         rcu_read_lock();
 735         mpath = mesh_path_lookup(target_addr, sdata);
 736         if (mpath) {
 737                 struct sta_info *sta;
 738
 739                 spin_lock_bh(&mpath->state_lock);
 740                 sta = next_hop_deref_protected(mpath);
 741                 if (mpath->flags & MESH_PATH_ACTIVE &&
 742                     ether_addr_equal(ta, sta->sta.addr) &&
 743                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 744                     SN_GT(target_sn, mpath->sn))) {
 745                         mpath->flags &= ~MESH_PATH_ACTIVE;
 746                         mpath->sn = target_sn;
 747                         spin_unlock_bh(&mpath->state_lock);
 748                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 749                                 goto endperr;
 750                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 751                                            cpu_to_le16(target_rcode),
 752                                            broadcast_addr, sdata);
 753                 } else
 754                         spin_unlock_bh(&mpath->state_lock);
 755         }
 756 endperr:
 757         rcu_read_unlock();
 758 }
 759
 760 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 761                                 struct ieee80211_mgmt *mgmt,
 762                                 struct ieee80211_rann_ie *rann)
 763 {
 764         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 765         struct ieee80211_local *local = sdata->local;
 766         struct sta_info *sta;
 767         struct mesh_path *mpath;
 768         u8 ttl, flags, hopcount;
 769         u8 *orig_addr;
 770         u32 orig_sn, metric, metric_txsta, interval;
 771         bool root_is_gate;
 772
 773         ttl = rann->rann_ttl;
 774         if (ttl <= 1) {
 775                 ifmsh->mshstats.dropped_frames_ttl++;
 776                 return;
 777         }
 778         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("received RANN from %pM via neighbour %pM (is_gate=%d)",
 793                         orig_addr, mgmt->sa, root_is_gate);
 794
 795         rcu_read_lock();
 796         sta = sta_info_get(sdata, mgmt->sa);
 797         if (!sta) {
 798                 rcu_read_unlock();
 799                 return;
 800         }
 801
 802         metric_txsta = airtime_link_metric_get(local, sta);
 803
 804         mpath = mesh_path_lookup(orig_addr, sdata);
 805         if (!mpath) {
 806                 mesh_path_add(orig_addr, sdata);
 807                 mpath = mesh_path_lookup(orig_addr, sdata);
 808                 if (!mpath) {
 809                         rcu_read_unlock();
 810                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 811                         return;
 812                 }
 813         }
 814
 815         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 816              (time_after(jiffies, mpath->last_preq_to_root +
 817                                   root_path_confirmation_jiffies(sdata)) ||
 818              time_before(jiffies, mpath->last_preq_to_root))) &&
 819              !(mpath->flags & MESH_PATH_FIXED)) {
 820                 mhwmp_dbg("%s time to refresh root mpath %pM", sdata->name,
 821                                                                orig_addr);
 822                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 823                 mpath->last_preq_to_root = jiffies;
 824         }
 825
 826         if ((SN_LT(mpath->sn, orig_sn) || (mpath->sn == orig_sn &&
 827            metric < mpath->rann_metric)) && ifmsh->mshcfg.dot11MeshForwarding) {
 828                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 829                                        cpu_to_le32(orig_sn),
 830                                        0, NULL, 0, broadcast_addr,
 831                                        hopcount, ttl, cpu_to_le32(interval),
 832                                        cpu_to_le32(metric + metric_txsta),
 833                                        0, sdata);
 834                 mpath->sn = orig_sn;
 835                 mpath->rann_metric = metric + metric_txsta;
 836                 /* Recording RANNs sender address to send individually
 837                  * addressed PREQs destined for root mesh STA */
 838                 memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 839         }
 840
 841         mpath->is_root = true;
 842
 843         if (root_is_gate)
 844                 mesh_path_add_gate(mpath);
 845
 846         rcu_read_unlock();
 847 }
 848
 849
 850 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 851                             struct ieee80211_mgmt *mgmt,
 852                             size_t len)
 853 {
 854         struct ieee802_11_elems elems;
 855         size_t baselen;
 856         u32 last_hop_metric;
 857         struct sta_info *sta;
 858
 859         /* need action_code */
 860         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 861                 return;
 862
 863         rcu_read_lock();
 864         sta = sta_info_get(sdata, mgmt->sa);
 865         if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 866                 rcu_read_unlock();
 867                 return;
 868         }
 869         rcu_read_unlock();
 870
 871         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 872         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 873                         len - baselen, &elems);
 874
 875         if (elems.preq) {
 876                 if (elems.preq_len != 37)
 877                         /* Right now we support just 1 destination and no AE */
 878                         return;
 879                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 880                                                       MPATH_PREQ);
 881                 if (last_hop_metric)
 882                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 883                                                 last_hop_metric);
 884         }
 885         if (elems.prep) {
 886                 if (elems.prep_len != 31)
 887                         /* Right now we support no AE */
 888                         return;
 889                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 890                                                       MPATH_PREP);
 891                 if (last_hop_metric)
 892                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 893                                                 last_hop_metric);
 894         }
 895         if (elems.perr) {
 896                 if (elems.perr_len != 15)
 897                         /* Right now we support only one destination per PERR */
 898                         return;
 899                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 900         }
 901         if (elems.rann)
 902                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 903 }
 904
 905 /**
 906  * mesh_queue_preq - queue a PREQ to a given destination
 907  *
 908  * @mpath: mesh path to discover
 909  * @flags: special attributes of the PREQ to be sent
 910  *
 911  * Locking: the function must be called from within a rcu read lock block.
 912  *
 913  */
 914 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 915 {
 916         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 917         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 918         struct mesh_preq_queue *preq_node;
 919
 920         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 921         if (!preq_node) {
 922                 mhwmp_dbg("could not allocate PREQ node");
 923                 return;
 924         }
 925
 926         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 927         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 928                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 929                 kfree(preq_node);
 930                 if (printk_ratelimit())
 931                         mhwmp_dbg("PREQ node queue full");
 932                 return;
 933         }
 934
 935         spin_lock(&mpath->state_lock);
 936         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 937                 spin_unlock(&mpath->state_lock);
 938                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 939                 kfree(preq_node);
 940                 return;
 941         }
 942
 943         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 944         preq_node->flags = flags;
 945
 946         mpath->flags |= MESH_PATH_REQ_QUEUED;
 947         spin_unlock(&mpath->state_lock);
 948
 949         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 950         ++ifmsh->preq_queue_len;
 951         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 952
 953         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 954                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 955
 956         else if (time_before(jiffies, ifmsh->last_preq)) {
 957                 /* avoid long wait if did not send preqs for a long time
 958                  * and jiffies wrapped around
 959                  */
 960                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 961                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 962         } else
 963                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 964                                                 min_preq_int_jiff(sdata));
 965 }
 966
 967 /**
 968  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 969  *
 970  * @sdata: local mesh subif
 971  */
 972 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 973 {
 974         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 975         struct mesh_preq_queue *preq_node;
 976         struct mesh_path *mpath;
 977         u8 ttl, target_flags;
 978         const u8 *da;
 979         u32 lifetime;
 980
 981         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 982         if (!ifmsh->preq_queue_len ||
 983                 time_before(jiffies, ifmsh->last_preq +
 984                                 min_preq_int_jiff(sdata))) {
 985                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 986                 return;
 987         }
 988
 989         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 990                         struct mesh_preq_queue, list);
 991         list_del(&preq_node->list);
 992         --ifmsh->preq_queue_len;
 993         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 994
 995         rcu_read_lock();
 996         mpath = mesh_path_lookup(preq_node->dst, sdata);
 997         if (!mpath)
 998                 goto enddiscovery;
 999
1000         spin_lock_bh(&mpath->state_lock);
1001         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1002         if (preq_node->flags & PREQ_Q_F_START) {
1003                 if (mpath->flags & MESH_PATH_RESOLVING) {
1004                         spin_unlock_bh(&mpath->state_lock);
1005                         goto enddiscovery;
1006                 } else {
1007                         mpath->flags &= ~MESH_PATH_RESOLVED;
1008                         mpath->flags |= MESH_PATH_RESOLVING;
1009                         mpath->discovery_retries = 0;
1010                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1011                 }
1012         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1013                         mpath->flags & MESH_PATH_RESOLVED) {
1014                 mpath->flags &= ~MESH_PATH_RESOLVING;
1015                 spin_unlock_bh(&mpath->state_lock);
1016                 goto enddiscovery;
1017         }
1018
1019         ifmsh->last_preq = jiffies;
1020
1021         if (time_after(jiffies, ifmsh->last_sn_update +
1022                                 net_traversal_jiffies(sdata)) ||
1023             time_before(jiffies, ifmsh->last_sn_update)) {
1024                 ++ifmsh->sn;
1025                 sdata->u.mesh.last_sn_update = jiffies;
1026         }
1027         lifetime = default_lifetime(sdata);
1028         ttl = sdata->u.mesh.mshcfg.element_ttl;
1029         if (ttl == 0) {
1030                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1031                 spin_unlock_bh(&mpath->state_lock);
1032                 goto enddiscovery;
1033         }
1034
1035         if (preq_node->flags & PREQ_Q_F_REFRESH)
1036                 target_flags = MP_F_DO;
1037         else
1038                 target_flags = MP_F_RF;
1039
1040         spin_unlock_bh(&mpath->state_lock);
1041         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1042         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1043                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1044                         cpu_to_le32(mpath->sn), da, 0,
1045                         ttl, cpu_to_le32(lifetime), 0,
1046                         cpu_to_le32(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 /* mesh_nexthop_resolve - lookup next hop for given skb and start path
1055  * discovery if no forwarding information is found.
1056  *
1057  * @skb: 802.11 frame to be sent
1058  * @sdata: network subif the frame will be sent through
1059  *
1060  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1061  * skb is freeed here if no mpath could be allocated.
1062  */
1063 int mesh_nexthop_resolve(struct sk_buff *skb,
1064                          struct ieee80211_sub_if_data *sdata)
1065 {
1066         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1067         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1068         struct mesh_path *mpath;
1069         struct sk_buff *skb_to_free = NULL;
1070         u8 *target_addr = hdr->addr3;
1071         int err = 0;
1072
1073         rcu_read_lock();
1074         err = mesh_nexthop_lookup(skb, sdata);
1075         if (!err)
1076                 goto endlookup;
1077
1078         /* no nexthop found, start resolving */
1079         mpath = mesh_path_lookup(target_addr, sdata);
1080         if (!mpath) {
1081                 mesh_path_add(target_addr, sdata);
1082                 mpath = mesh_path_lookup(target_addr, sdata);
1083                 if (!mpath) {
1084                         mesh_path_discard_frame(skb, sdata);
1085                         err = -ENOSPC;
1086                         goto endlookup;
1087                 }
1088         }
1089
1090         if (!(mpath->flags & MESH_PATH_RESOLVING))
1091                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1092
1093         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1094                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1095
1096         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1097         ieee80211_set_qos_hdr(sdata, skb);
1098         skb_queue_tail(&mpath->frame_queue, skb);
1099         err = -ENOENT;
1100         if (skb_to_free)
1101                 mesh_path_discard_frame(skb_to_free, sdata);
1102
1103 endlookup:
1104         rcu_read_unlock();
1105         return err;
1106 }
1107 /**
1108  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1109  * this function is considered "using" the associated mpath, so preempt a path
1110  * refresh if this mpath expires soon.
1111  *
1112  * @skb: 802.11 frame to be sent
1113  * @sdata: network subif the frame will be sent through
1114  *
1115  * Returns: 0 if the next hop was found. Nonzero otherwise.
1116  */
1117 int mesh_nexthop_lookup(struct sk_buff *skb,
1118                         struct ieee80211_sub_if_data *sdata)
1119 {
1120         struct mesh_path *mpath;
1121         struct sta_info *next_hop;
1122         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1123         u8 *target_addr = hdr->addr3;
1124         int err = -ENOENT;
1125
1126         rcu_read_lock();
1127         mpath = mesh_path_lookup(target_addr, sdata);
1128
1129         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1130                 goto endlookup;
1131
1132         if (time_after(jiffies,
1133                        mpath->exp_time -
1134                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1135             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1136             !(mpath->flags & MESH_PATH_RESOLVING) &&
1137             !(mpath->flags & MESH_PATH_FIXED))
1138                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1139
1140         next_hop = rcu_dereference(mpath->next_hop);
1141         if (next_hop) {
1142                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1143                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1144                 err = 0;
1145         }
1146
1147 endlookup:
1148         rcu_read_unlock();
1149         return err;
1150 }
1151
1152 void mesh_path_timer(unsigned long data)
1153 {
1154         struct mesh_path *mpath = (void *) data;
1155         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1156         int ret;
1157
1158         if (sdata->local->quiescing)
1159                 return;
1160
1161         spin_lock_bh(&mpath->state_lock);
1162         if (mpath->flags & MESH_PATH_RESOLVED ||
1163                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1164                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1165                 spin_unlock_bh(&mpath->state_lock);
1166         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1167                 ++mpath->discovery_retries;
1168                 mpath->discovery_timeout *= 2;
1169                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1170                 spin_unlock_bh(&mpath->state_lock);
1171                 mesh_queue_preq(mpath, 0);
1172         } else {
1173                 mpath->flags = 0;
1174                 mpath->exp_time = jiffies;
1175                 spin_unlock_bh(&mpath->state_lock);
1176                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1177                         ret = mesh_path_send_to_gates(mpath);
1178                         if (ret)
1179                                 mhwmp_dbg("no gate was reachable");
1180                 } else
1181                         mesh_path_flush_pending(mpath);
1182         }
1183 }
1184
1185 void
1186 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1187 {
1188         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1189         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1190         u8 flags, target_flags = 0;
1191
1192         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1193                         ? RANN_FLAG_IS_GATE : 0;
1194
1195         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1196         case IEEE80211_PROACTIVE_RANN:
1197                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1198                                cpu_to_le32(++ifmsh->sn),
1199                                0, NULL, 0, broadcast_addr,
1200                                0, ifmsh->mshcfg.element_ttl,
1201                                cpu_to_le32(interval), 0, 0, sdata);
1202                 break;
1203         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1204                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1205         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1206                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1207                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1208                                 IEEE80211_PREQ_USN_FLAG;
1209                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1210                                 cpu_to_le32(++ifmsh->sn), target_flags,
1211                                 (u8 *) broadcast_addr, 0, broadcast_addr,
1212                                 0, ifmsh->mshcfg.element_ttl,
1213                                 cpu_to_le32(interval),
1214                                 0, cpu_to_le32(ifmsh->preq_id++), sdata);
1215                 break;
1216         default:
1217                 mhwmp_dbg("Proactive mechanism not supported");
1218                 return;
1219         }
1220 }