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 /* Number of frames buffered per destination for unresolved destinations */
  21 #define MESH_FRAME_QUEUE_LEN    10
  22 #define MAX_PREQ_QUEUE_LEN      64
  23
  24 /* Destination only */
  25 #define MP_F_DO 0x1
  26 /* Reply and forward */
  27 #define MP_F_RF 0x2
  28 /* Unknown Sequence Number */
  29 #define MP_F_USN    0x01
  30 /* Reason code Present */
  31 #define MP_F_RCODE  0x02
  32
  33 static void mesh_queue_preq(struct mesh_path *, u8);
  34
  35 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
  36 {
  37         if (ae)
  38                 offset += 6;
  39         return get_unaligned_le32(preq_elem + offset);
  40 }
  41
  42 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
  43 {
  44         if (ae)
  45                 offset += 6;
  46         return get_unaligned_le16(preq_elem + offset);
  47 }
  48
  49 /* HWMP IE processing macros */
  50 #define AE_F                    (1<<6)
  51 #define AE_F_SET(x)             (*x & AE_F)
  52 #define PREQ_IE_FLAGS(x)        (*(x))
  53 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  54 #define PREQ_IE_TTL(x)          (*(x + 2))
  55 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  56 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  57 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  58 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  59 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  60 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  61 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  62 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  63
  64
  65 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  66 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  67 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  68 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  69 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  70 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  71 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  72 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  73 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  74
  75 #define PERR_IE_TTL(x)          (*(x))
  76 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  77 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  78 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  79 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  80
  81 #define MSEC_TO_TU(x) (x*1000/1024)
  82 #define SN_GT(x, y) ((s32)(y - x) < 0)
  83 #define SN_LT(x, y) ((s32)(x - y) < 0)
  84
  85 #define net_traversal_jiffies(s) \
  86         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  87 #define default_lifetime(s) \
  88         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  89 #define min_preq_int_jiff(s) \
  90         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  91 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  92 #define disc_timeout_jiff(s) \
  93         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  94 #define root_path_confirmation_jiffies(s) \
  95         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  96
  97 enum mpath_frame_type {
  98         MPATH_PREQ = 0,
  99         MPATH_PREP,
 100         MPATH_PERR,
 101         MPATH_RANN
 102 };
 103
 104 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 105
 106 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 107                 u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
 108                 __le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
 109                 __le32 lifetime, __le32 metric, __le32 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", target);
 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                 memcpy(pos, &target_sn, 4);
 170                 pos += 4;
 171         } else {
 172                 if (action == MPATH_PREQ) {
 173                         memcpy(pos, &preq_id, 4);
 174                         pos += 4;
 175                 }
 176                 memcpy(pos, orig_addr, ETH_ALEN);
 177                 pos += ETH_ALEN;
 178                 memcpy(pos, &orig_sn, 4);
 179                 pos += 4;
 180         }
 181         memcpy(pos, &lifetime, 4);      /* interval for RANN */
 182         pos += 4;
 183         memcpy(pos, &metric, 4);
 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                 memcpy(pos, &target_sn, 4);
 191                 pos += 4;
 192         } else if (action == MPATH_PREP) {
 193                 memcpy(pos, orig_addr, ETH_ALEN);
 194                 pos += ETH_ALEN;
 195                 memcpy(pos, &orig_sn, 4);
 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
 211         skb_set_mac_header(skb, 0);
 212         skb_set_network_header(skb, 0);
 213         skb_set_transport_header(skb, 0);
 214
 215         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 216         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 217         skb->priority = 7;
 218
 219         info->control.vif = &sdata->vif;
 220         ieee80211_set_qos_hdr(sdata, skb);
 221 }
 222
 223 /**
 224  * mesh_send_path error - Sends a PERR mesh management frame
 225  *
 226  * @target: broken destination
 227  * @target_sn: SN of the broken destination
 228  * @target_rcode: reason code for this PERR
 229  * @ra: node this frame is addressed to
 230  *
 231  * Note: This function may be called with driver locks taken that the driver
 232  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 233  * frame directly but add it to the pending queue instead.
 234  */
 235 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 236                        __le16 target_rcode, const u8 *ra,
 237                        struct ieee80211_sub_if_data *sdata)
 238 {
 239         struct ieee80211_local *local = sdata->local;
 240         struct sk_buff *skb;
 241         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 242         struct ieee80211_mgmt *mgmt;
 243         u8 *pos, ie_len;
 244         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 245                       sizeof(mgmt->u.action.u.mesh_action);
 246
 247         if (time_before(jiffies, ifmsh->next_perr))
 248                 return -EAGAIN;
 249
 250         skb = dev_alloc_skb(local->tx_headroom +
 251                             hdr_len +
 252                             2 + 15 /* PERR IE */);
 253         if (!skb)
 254                 return -1;
 255         skb_reserve(skb, local->tx_headroom);
 256         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 257         memset(mgmt, 0, hdr_len);
 258         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 259                                           IEEE80211_STYPE_ACTION);
 260
 261         memcpy(mgmt->da, ra, ETH_ALEN);
 262         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 263         /* BSSID == SA */
 264         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 265         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 266         mgmt->u.action.u.mesh_action.action_code =
 267                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 268         ie_len = 15;
 269         pos = skb_put(skb, 2 + ie_len);
 270         *pos++ = WLAN_EID_PERR;
 271         *pos++ = ie_len;
 272         /* ttl */
 273         *pos++ = ttl;
 274         /* number of destinations */
 275         *pos++ = 1;
 276         /*
 277          * flags bit, bit 1 is unset if we know the sequence number and
 278          * bit 2 is set if we have a reason code
 279          */
 280         *pos = 0;
 281         if (!target_sn)
 282                 *pos |= MP_F_USN;
 283         if (target_rcode)
 284                 *pos |= MP_F_RCODE;
 285         pos++;
 286         memcpy(pos, target, ETH_ALEN);
 287         pos += ETH_ALEN;
 288         memcpy(pos, &target_sn, 4);
 289         pos += 4;
 290         memcpy(pos, &target_rcode, 2);
 291
 292         /* see note in function header */
 293         prepare_frame_for_deferred_tx(sdata, skb);
 294         ifmsh->next_perr = TU_TO_EXP_TIME(
 295                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 296         ieee80211_add_pending_skb(local, skb);
 297         return 0;
 298 }
 299
 300 void ieee80211s_update_metric(struct ieee80211_local *local,
 301                 struct sta_info *sta, struct sk_buff *skb)
 302 {
 303         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 304         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 305         int failed;
 306
 307         if (!ieee80211_is_data(hdr->frame_control))
 308                 return;
 309
 310         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 311
 312         /* moving average, scaled to 100 */
 313         sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
 314         if (sta->fail_avg > 95)
 315                 mesh_plink_broken(sta);
 316 }
 317
 318 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 319                                    struct sta_info *sta)
 320 {
 321         struct rate_info rinfo;
 322         /* This should be adjusted for each device */
 323         int device_constant = 1 << ARITH_SHIFT;
 324         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 325         int s_unit = 1 << ARITH_SHIFT;
 326         int rate, err;
 327         u32 tx_time, estimated_retx;
 328         u64 result;
 329
 330         if (sta->fail_avg >= 100)
 331                 return MAX_METRIC;
 332
 333         sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
 334         rate = cfg80211_calculate_bitrate(&rinfo);
 335         if (WARN_ON(!rate))
 336                 return MAX_METRIC;
 337
 338         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 339
 340         /* bitrate is in units of 100 Kbps, while we need rate in units of
 341          * 1Mbps. This will be corrected on tx_time computation.
 342          */
 343         tx_time = (device_constant + 10 * test_frame_len / rate);
 344         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 345         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 346         return (u32)result;
 347 }
 348
 349 /**
 350  * hwmp_route_info_get - Update routing info to originator and transmitter
 351  *
 352  * @sdata: local mesh subif
 353  * @mgmt: mesh management frame
 354  * @hwmp_ie: hwmp information element (PREP or PREQ)
 355  *
 356  * This function updates the path routing information to the originator and the
 357  * transmitter of a HWMP PREQ or PREP frame.
 358  *
 359  * Returns: metric to frame originator or 0 if the frame should not be further
 360  * processed
 361  *
 362  * Notes: this function is the only place (besides user-provided info) where
 363  * path routing information is updated.
 364  */
 365 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 366                             struct ieee80211_mgmt *mgmt,
 367                             u8 *hwmp_ie, enum mpath_frame_type action)
 368 {
 369         struct ieee80211_local *local = sdata->local;
 370         struct mesh_path *mpath;
 371         struct sta_info *sta;
 372         bool fresh_info;
 373         u8 *orig_addr, *ta;
 374         u32 orig_sn, orig_metric;
 375         unsigned long orig_lifetime, exp_time;
 376         u32 last_hop_metric, new_metric;
 377         bool process = true;
 378
 379         rcu_read_lock();
 380         sta = sta_info_get(sdata, mgmt->sa);
 381         if (!sta) {
 382                 rcu_read_unlock();
 383                 return 0;
 384         }
 385
 386         last_hop_metric = airtime_link_metric_get(local, sta);
 387         /* Update and check originator routing info */
 388         fresh_info = true;
 389
 390         switch (action) {
 391         case MPATH_PREQ:
 392                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 393                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 394                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 395                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 396                 break;
 397         case MPATH_PREP:
 398                 /* Originator here refers to the MP that was the target in the
 399                  * Path Request. We divert from the nomenclature in the draft
 400                  * so that we can easily use a single function to gather path
 401                  * information from both PREQ and PREP frames.
 402                  */
 403                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 404                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 405                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 406                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 407                 break;
 408         default:
 409                 rcu_read_unlock();
 410                 return 0;
 411         }
 412         new_metric = orig_metric + last_hop_metric;
 413         if (new_metric < orig_metric)
 414                 new_metric = MAX_METRIC;
 415         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 416
 417         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 418                 /* This MP is the originator, we are not interested in this
 419                  * frame, except for updating transmitter's path info.
 420                  */
 421                 process = false;
 422                 fresh_info = false;
 423         } else {
 424                 mpath = mesh_path_lookup(orig_addr, sdata);
 425                 if (mpath) {
 426                         spin_lock_bh(&mpath->state_lock);
 427                         if (mpath->flags & MESH_PATH_FIXED)
 428                                 fresh_info = false;
 429                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 430                             (mpath->flags & MESH_PATH_SN_VALID)) {
 431                                 if (SN_GT(mpath->sn, orig_sn) ||
 432                                     (mpath->sn == orig_sn &&
 433                                      new_metric >= mpath->metric)) {
 434                                         process = false;
 435                                         fresh_info = false;
 436                                 }
 437                         }
 438                 } else {
 439                         mesh_path_add(orig_addr, sdata);
 440                         mpath = mesh_path_lookup(orig_addr, sdata);
 441                         if (!mpath) {
 442                                 rcu_read_unlock();
 443                                 return 0;
 444                         }
 445                         spin_lock_bh(&mpath->state_lock);
 446                 }
 447
 448                 if (fresh_info) {
 449                         mesh_path_assign_nexthop(mpath, sta);
 450                         mpath->flags |= MESH_PATH_SN_VALID;
 451                         mpath->metric = new_metric;
 452                         mpath->sn = orig_sn;
 453                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 454                                           ?  mpath->exp_time : exp_time;
 455                         mesh_path_activate(mpath);
 456                         spin_unlock_bh(&mpath->state_lock);
 457                         mesh_path_tx_pending(mpath);
 458                         /* draft says preq_id should be saved to, but there does
 459                          * not seem to be any use for it, skipping by now
 460                          */
 461                 } else
 462                         spin_unlock_bh(&mpath->state_lock);
 463         }
 464
 465         /* Update and check transmitter routing info */
 466         ta = mgmt->sa;
 467         if (ether_addr_equal(orig_addr, ta))
 468                 fresh_info = false;
 469         else {
 470                 fresh_info = true;
 471
 472                 mpath = mesh_path_lookup(ta, sdata);
 473                 if (mpath) {
 474                         spin_lock_bh(&mpath->state_lock);
 475                         if ((mpath->flags & MESH_PATH_FIXED) ||
 476                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 477                                         (last_hop_metric > mpath->metric)))
 478                                 fresh_info = false;
 479                 } else {
 480                         mesh_path_add(ta, sdata);
 481                         mpath = mesh_path_lookup(ta, sdata);
 482                         if (!mpath) {
 483                                 rcu_read_unlock();
 484                                 return 0;
 485                         }
 486                         spin_lock_bh(&mpath->state_lock);
 487                 }
 488
 489                 if (fresh_info) {
 490                         mesh_path_assign_nexthop(mpath, sta);
 491                         mpath->metric = last_hop_metric;
 492                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 493                                           ?  mpath->exp_time : exp_time;
 494                         mesh_path_activate(mpath);
 495                         spin_unlock_bh(&mpath->state_lock);
 496                         mesh_path_tx_pending(mpath);
 497                 } else
 498                         spin_unlock_bh(&mpath->state_lock);
 499         }
 500
 501         rcu_read_unlock();
 502
 503         return process ? new_metric : 0;
 504 }
 505
 506 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 507                                     struct ieee80211_mgmt *mgmt,
 508                                     u8 *preq_elem, u32 metric)
 509 {
 510         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 511         struct mesh_path *mpath = NULL;
 512         u8 *target_addr, *orig_addr;
 513         const u8 *da;
 514         u8 target_flags, ttl, flags;
 515         u32 orig_sn, target_sn, lifetime, orig_metric;
 516         bool reply = false;
 517         bool forward = true;
 518         bool root_is_gate;
 519
 520         /* Update target SN, if present */
 521         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 522         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 523         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 524         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 525         target_flags = PREQ_IE_TARGET_F(preq_elem);
 526         orig_metric = metric;
 527         /* Proactive PREQ gate announcements */
 528         flags = PREQ_IE_FLAGS(preq_elem);
 529         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 530
 531         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 532
 533         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 534                 mhwmp_dbg(sdata, "PREQ is for us\n");
 535                 forward = false;
 536                 reply = true;
 537                 metric = 0;
 538                 if (time_after(jiffies, ifmsh->last_sn_update +
 539                                         net_traversal_jiffies(sdata)) ||
 540                     time_before(jiffies, ifmsh->last_sn_update)) {
 541                         target_sn = ++ifmsh->sn;
 542                         ifmsh->last_sn_update = jiffies;
 543                 }
 544         } else if (is_broadcast_ether_addr(target_addr) &&
 545                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 546                 rcu_read_lock();
 547                 mpath = mesh_path_lookup(orig_addr, sdata);
 548                 if (mpath) {
 549                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 550                                 reply = true;
 551                                 target_addr = sdata->vif.addr;
 552                                 target_sn = ++ifmsh->sn;
 553                                 metric = 0;
 554                                 ifmsh->last_sn_update = jiffies;
 555                         }
 556                         if (root_is_gate)
 557                                 mesh_path_add_gate(mpath);
 558                 }
 559                 rcu_read_unlock();
 560         } else {
 561                 rcu_read_lock();
 562                 mpath = mesh_path_lookup(target_addr, sdata);
 563                 if (mpath) {
 564                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 565                                         SN_LT(mpath->sn, target_sn)) {
 566                                 mpath->sn = target_sn;
 567                                 mpath->flags |= MESH_PATH_SN_VALID;
 568                         } else if ((!(target_flags & MP_F_DO)) &&
 569                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 570                                 reply = true;
 571                                 metric = mpath->metric;
 572                                 target_sn = mpath->sn;
 573                                 if (target_flags & MP_F_RF)
 574                                         target_flags |= MP_F_DO;
 575                                 else
 576                                         forward = false;
 577                         }
 578                 }
 579                 rcu_read_unlock();
 580         }
 581
 582         if (reply) {
 583                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 584                 ttl = ifmsh->mshcfg.element_ttl;
 585                 if (ttl != 0) {
 586                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 587                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 588                                 cpu_to_le32(orig_sn), 0, target_addr,
 589                                 cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 590                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 591                                 0, sdata);
 592                 } else {
 593                         ifmsh->mshstats.dropped_frames_ttl++;
 594                 }
 595         }
 596
 597         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 598                 u32 preq_id;
 599                 u8 hopcount;
 600
 601                 ttl = PREQ_IE_TTL(preq_elem);
 602                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 603                 if (ttl <= 1) {
 604                         ifmsh->mshstats.dropped_frames_ttl++;
 605                         return;
 606                 }
 607                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 608                 --ttl;
 609                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 610                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 611                 da = (mpath && mpath->is_root) ?
 612                         mpath->rann_snd_addr : broadcast_addr;
 613
 614                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 615                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 616                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 617                         metric = orig_metric;
 618                 }
 619
 620                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 621                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 622                                 cpu_to_le32(target_sn), da,
 623                                 hopcount, ttl, cpu_to_le32(lifetime),
 624                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 625                                 sdata);
 626                 if (!is_multicast_ether_addr(da))
 627                         ifmsh->mshstats.fwded_unicast++;
 628                 else
 629                         ifmsh->mshstats.fwded_mcast++;
 630                 ifmsh->mshstats.fwded_frames++;
 631         }
 632 }
 633
 634
 635 static inline struct sta_info *
 636 next_hop_deref_protected(struct mesh_path *mpath)
 637 {
 638         return rcu_dereference_protected(mpath->next_hop,
 639                                          lockdep_is_held(&mpath->state_lock));
 640 }
 641
 642
 643 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 644                                     struct ieee80211_mgmt *mgmt,
 645                                     u8 *prep_elem, u32 metric)
 646 {
 647         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 648         struct mesh_path *mpath;
 649         u8 *target_addr, *orig_addr;
 650         u8 ttl, hopcount, flags;
 651         u8 next_hop[ETH_ALEN];
 652         u32 target_sn, orig_sn, lifetime;
 653
 654         mhwmp_dbg(sdata, "received PREP from %pM\n",
 655                   PREP_IE_ORIG_ADDR(prep_elem));
 656
 657         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 658         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 659                 /* destination, no forwarding required */
 660                 return;
 661
 662         if (!ifmsh->mshcfg.dot11MeshForwarding)
 663                 return;
 664
 665         ttl = PREP_IE_TTL(prep_elem);
 666         if (ttl <= 1) {
 667                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 668                 return;
 669         }
 670
 671         rcu_read_lock();
 672         mpath = mesh_path_lookup(orig_addr, sdata);
 673         if (mpath)
 674                 spin_lock_bh(&mpath->state_lock);
 675         else
 676                 goto fail;
 677         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 678                 spin_unlock_bh(&mpath->state_lock);
 679                 goto fail;
 680         }
 681         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 682         spin_unlock_bh(&mpath->state_lock);
 683         --ttl;
 684         flags = PREP_IE_FLAGS(prep_elem);
 685         lifetime = PREP_IE_LIFETIME(prep_elem);
 686         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 687         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 688         target_sn = PREP_IE_TARGET_SN(prep_elem);
 689         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 690
 691         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 692                 cpu_to_le32(orig_sn), 0, target_addr,
 693                 cpu_to_le32(target_sn), next_hop, hopcount,
 694                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 695                 0, sdata);
 696         rcu_read_unlock();
 697
 698         sdata->u.mesh.mshstats.fwded_unicast++;
 699         sdata->u.mesh.mshstats.fwded_frames++;
 700         return;
 701
 702 fail:
 703         rcu_read_unlock();
 704         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 705 }
 706
 707 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 708                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 709 {
 710         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 711         struct mesh_path *mpath;
 712         u8 ttl;
 713         u8 *ta, *target_addr;
 714         u32 target_sn;
 715         u16 target_rcode;
 716
 717         ta = mgmt->sa;
 718         ttl = PERR_IE_TTL(perr_elem);
 719         if (ttl <= 1) {
 720                 ifmsh->mshstats.dropped_frames_ttl++;
 721                 return;
 722         }
 723         ttl--;
 724         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 725         target_sn = PERR_IE_TARGET_SN(perr_elem);
 726         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 727
 728         rcu_read_lock();
 729         mpath = mesh_path_lookup(target_addr, sdata);
 730         if (mpath) {
 731                 struct sta_info *sta;
 732
 733                 spin_lock_bh(&mpath->state_lock);
 734                 sta = next_hop_deref_protected(mpath);
 735                 if (mpath->flags & MESH_PATH_ACTIVE &&
 736                     ether_addr_equal(ta, sta->sta.addr) &&
 737                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 738                     SN_GT(target_sn, mpath->sn))) {
 739                         mpath->flags &= ~MESH_PATH_ACTIVE;
 740                         mpath->sn = target_sn;
 741                         spin_unlock_bh(&mpath->state_lock);
 742                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 743                                 goto endperr;
 744                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 745                                            cpu_to_le16(target_rcode),
 746                                            broadcast_addr, sdata);
 747                 } else
 748                         spin_unlock_bh(&mpath->state_lock);
 749         }
 750 endperr:
 751         rcu_read_unlock();
 752 }
 753
 754 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 755                                 struct ieee80211_mgmt *mgmt,
 756                                 struct ieee80211_rann_ie *rann)
 757 {
 758         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 759         struct ieee80211_local *local = sdata->local;
 760         struct sta_info *sta;
 761         struct mesh_path *mpath;
 762         u8 ttl, flags, hopcount;
 763         u8 *orig_addr;
 764         u32 orig_sn, metric, metric_txsta, interval;
 765         bool root_is_gate;
 766
 767         ttl = rann->rann_ttl;
 768         flags = rann->rann_flags;
 769         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 770         orig_addr = rann->rann_addr;
 771         orig_sn = le32_to_cpu(rann->rann_seq);
 772         interval = le32_to_cpu(rann->rann_interval);
 773         hopcount = rann->rann_hopcount;
 774         hopcount++;
 775         metric = le32_to_cpu(rann->rann_metric);
 776
 777         /*  Ignore our own RANNs */
 778         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 779                 return;
 780
 781         mhwmp_dbg(sdata,
 782                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 783                   orig_addr, mgmt->sa, root_is_gate);
 784
 785         rcu_read_lock();
 786         sta = sta_info_get(sdata, mgmt->sa);
 787         if (!sta) {
 788                 rcu_read_unlock();
 789                 return;
 790         }
 791
 792         metric_txsta = airtime_link_metric_get(local, sta);
 793
 794         mpath = mesh_path_lookup(orig_addr, sdata);
 795         if (!mpath) {
 796                 mesh_path_add(orig_addr, sdata);
 797                 mpath = mesh_path_lookup(orig_addr, sdata);
 798                 if (!mpath) {
 799                         rcu_read_unlock();
 800                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 801                         return;
 802                 }
 803         }
 804
 805         if (!(SN_LT(mpath->sn, orig_sn)) &&
 806             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 807                 rcu_read_unlock();
 808                 return;
 809         }
 810
 811         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 812              (time_after(jiffies, mpath->last_preq_to_root +
 813                                   root_path_confirmation_jiffies(sdata)) ||
 814              time_before(jiffies, mpath->last_preq_to_root))) &&
 815              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 816                 mhwmp_dbg(sdata,
 817                           "time to refresh root mpath %pM\n",
 818                           orig_addr);
 819                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 820                 mpath->last_preq_to_root = jiffies;
 821         }
 822
 823         mpath->sn = orig_sn;
 824         mpath->rann_metric = metric + metric_txsta;
 825         mpath->is_root = true;
 826         /* Recording RANNs sender address to send individually
 827          * addressed PREQs destined for root mesh STA */
 828         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 829
 830         if (root_is_gate)
 831                 mesh_path_add_gate(mpath);
 832
 833         if (ttl <= 1) {
 834                 ifmsh->mshstats.dropped_frames_ttl++;
 835                 rcu_read_unlock();
 836                 return;
 837         }
 838         ttl--;
 839
 840         if (ifmsh->mshcfg.dot11MeshForwarding) {
 841                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 842                                        cpu_to_le32(orig_sn),
 843                                        0, NULL, 0, broadcast_addr,
 844                                        hopcount, ttl, cpu_to_le32(interval),
 845                                        cpu_to_le32(metric + metric_txsta),
 846                                        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,
 855                             size_t len)
 856 {
 857         struct ieee802_11_elems elems;
 858         size_t baselen;
 859         u32 last_hop_metric;
 860         struct sta_info *sta;
 861
 862         /* need action_code */
 863         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 864                 return;
 865
 866         rcu_read_lock();
 867         sta = sta_info_get(sdata, mgmt->sa);
 868         if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 869                 rcu_read_unlock();
 870                 return;
 871         }
 872         rcu_read_unlock();
 873
 874         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 875         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 876                         len - baselen, &elems);
 877
 878         if (elems.preq) {
 879                 if (elems.preq_len != 37)
 880                         /* Right now we support just 1 destination and no AE */
 881                         return;
 882                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 883                                                       MPATH_PREQ);
 884                 if (last_hop_metric)
 885                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 886                                                 last_hop_metric);
 887         }
 888         if (elems.prep) {
 889                 if (elems.prep_len != 31)
 890                         /* Right now we support no AE */
 891                         return;
 892                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 893                                                       MPATH_PREP);
 894                 if (last_hop_metric)
 895                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 896                                                 last_hop_metric);
 897         }
 898         if (elems.perr) {
 899                 if (elems.perr_len != 15)
 900                         /* Right now we support only one destination per PERR */
 901                         return;
 902                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 903         }
 904         if (elems.rann)
 905                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 906 }
 907
 908 /**
 909  * mesh_queue_preq - queue a PREQ to a given destination
 910  *
 911  * @mpath: mesh path to discover
 912  * @flags: special attributes of the PREQ to be sent
 913  *
 914  * Locking: the function must be called from within a rcu read lock block.
 915  *
 916  */
 917 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 918 {
 919         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 920         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 921         struct mesh_preq_queue *preq_node;
 922
 923         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 924         if (!preq_node) {
 925                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 926                 return;
 927         }
 928
 929         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 930         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 931                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 932                 kfree(preq_node);
 933                 if (printk_ratelimit())
 934                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 935                 return;
 936         }
 937
 938         spin_lock(&mpath->state_lock);
 939         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 940                 spin_unlock(&mpath->state_lock);
 941                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 942                 kfree(preq_node);
 943                 return;
 944         }
 945
 946         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 947         preq_node->flags = flags;
 948
 949         mpath->flags |= MESH_PATH_REQ_QUEUED;
 950         spin_unlock(&mpath->state_lock);
 951
 952         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 953         ++ifmsh->preq_queue_len;
 954         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 955
 956         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 957                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 958
 959         else if (time_before(jiffies, ifmsh->last_preq)) {
 960                 /* avoid long wait if did not send preqs for a long time
 961                  * and jiffies wrapped around
 962                  */
 963                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 964                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 965         } else
 966                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 967                                                 min_preq_int_jiff(sdata));
 968 }
 969
 970 /**
 971  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 972  *
 973  * @sdata: local mesh subif
 974  */
 975 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 976 {
 977         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 978         struct mesh_preq_queue *preq_node;
 979         struct mesh_path *mpath;
 980         u8 ttl, target_flags;
 981         const u8 *da;
 982         u32 lifetime;
 983
 984         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 985         if (!ifmsh->preq_queue_len ||
 986                 time_before(jiffies, ifmsh->last_preq +
 987                                 min_preq_int_jiff(sdata))) {
 988                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 989                 return;
 990         }
 991
 992         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 993                         struct mesh_preq_queue, list);
 994         list_del(&preq_node->list);
 995         --ifmsh->preq_queue_len;
 996         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 997
 998         rcu_read_lock();
 999         mpath = mesh_path_lookup(preq_node->dst, sdata);
1000         if (!mpath)
1001                 goto enddiscovery;
1002
1003         spin_lock_bh(&mpath->state_lock);
1004         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1005         if (preq_node->flags & PREQ_Q_F_START) {
1006                 if (mpath->flags & MESH_PATH_RESOLVING) {
1007                         spin_unlock_bh(&mpath->state_lock);
1008                         goto enddiscovery;
1009                 } else {
1010                         mpath->flags &= ~MESH_PATH_RESOLVED;
1011                         mpath->flags |= MESH_PATH_RESOLVING;
1012                         mpath->discovery_retries = 0;
1013                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1014                 }
1015         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1016                         mpath->flags & MESH_PATH_RESOLVED) {
1017                 mpath->flags &= ~MESH_PATH_RESOLVING;
1018                 spin_unlock_bh(&mpath->state_lock);
1019                 goto enddiscovery;
1020         }
1021
1022         ifmsh->last_preq = jiffies;
1023
1024         if (time_after(jiffies, ifmsh->last_sn_update +
1025                                 net_traversal_jiffies(sdata)) ||
1026             time_before(jiffies, ifmsh->last_sn_update)) {
1027                 ++ifmsh->sn;
1028                 sdata->u.mesh.last_sn_update = jiffies;
1029         }
1030         lifetime = default_lifetime(sdata);
1031         ttl = sdata->u.mesh.mshcfg.element_ttl;
1032         if (ttl == 0) {
1033                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1034                 spin_unlock_bh(&mpath->state_lock);
1035                 goto enddiscovery;
1036         }
1037
1038         if (preq_node->flags & PREQ_Q_F_REFRESH)
1039                 target_flags = MP_F_DO;
1040         else
1041                 target_flags = MP_F_RF;
1042
1043         spin_unlock_bh(&mpath->state_lock);
1044         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1045         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1046                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1047                         cpu_to_le32(mpath->sn), da, 0,
1048                         ttl, cpu_to_le32(lifetime), 0,
1049                         cpu_to_le32(ifmsh->preq_id++), sdata);
1050         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1051
1052 enddiscovery:
1053         rcu_read_unlock();
1054         kfree(preq_node);
1055 }
1056
1057 /* mesh_nexthop_resolve - lookup next hop for given skb and start path
1058  * discovery if no forwarding information is found.
1059  *
1060  * @skb: 802.11 frame to be sent
1061  * @sdata: network subif the frame will be sent through
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 sk_buff *skb,
1067                          struct ieee80211_sub_if_data *sdata)
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         rcu_read_lock();
1077         err = mesh_nexthop_lookup(skb, sdata);
1078         if (!err)
1079                 goto endlookup;
1080
1081         /* no nexthop found, start resolving */
1082         mpath = mesh_path_lookup(target_addr, sdata);
1083         if (!mpath) {
1084                 mesh_path_add(target_addr, sdata);
1085                 mpath = mesh_path_lookup(target_addr, sdata);
1086                 if (!mpath) {
1087                         mesh_path_discard_frame(skb, sdata);
1088                         err = -ENOSPC;
1089                         goto endlookup;
1090                 }
1091         }
1092
1093         if (!(mpath->flags & MESH_PATH_RESOLVING))
1094                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1095
1096         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1097                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1098
1099         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1100         ieee80211_set_qos_hdr(sdata, skb);
1101         skb_queue_tail(&mpath->frame_queue, skb);
1102         err = -ENOENT;
1103         if (skb_to_free)
1104                 mesh_path_discard_frame(skb_to_free, sdata);
1105
1106 endlookup:
1107         rcu_read_unlock();
1108         return err;
1109 }
1110 /**
1111  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1112  * this function is considered "using" the associated mpath, so preempt a path
1113  * refresh if this mpath expires soon.
1114  *
1115  * @skb: 802.11 frame to be sent
1116  * @sdata: network subif the frame will be sent through
1117  *
1118  * Returns: 0 if the next hop was found. Nonzero otherwise.
1119  */
1120 int mesh_nexthop_lookup(struct sk_buff *skb,
1121                         struct ieee80211_sub_if_data *sdata)
1122 {
1123         struct mesh_path *mpath;
1124         struct sta_info *next_hop;
1125         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1126         u8 *target_addr = hdr->addr3;
1127         int err = -ENOENT;
1128
1129         rcu_read_lock();
1130         mpath = mesh_path_lookup(target_addr, sdata);
1131
1132         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1133                 goto endlookup;
1134
1135         if (time_after(jiffies,
1136                        mpath->exp_time -
1137                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1138             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1139             !(mpath->flags & MESH_PATH_RESOLVING) &&
1140             !(mpath->flags & MESH_PATH_FIXED))
1141                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1142
1143         next_hop = rcu_dereference(mpath->next_hop);
1144         if (next_hop) {
1145                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1146                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1147                 err = 0;
1148         }
1149
1150 endlookup:
1151         rcu_read_unlock();
1152         return err;
1153 }
1154
1155 void mesh_path_timer(unsigned long data)
1156 {
1157         struct mesh_path *mpath = (void *) data;
1158         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1159         int ret;
1160
1161         if (sdata->local->quiescing)
1162                 return;
1163
1164         spin_lock_bh(&mpath->state_lock);
1165         if (mpath->flags & MESH_PATH_RESOLVED ||
1166                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1167                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1168                 spin_unlock_bh(&mpath->state_lock);
1169         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1170                 ++mpath->discovery_retries;
1171                 mpath->discovery_timeout *= 2;
1172                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1173                 spin_unlock_bh(&mpath->state_lock);
1174                 mesh_queue_preq(mpath, 0);
1175         } else {
1176                 mpath->flags = 0;
1177                 mpath->exp_time = jiffies;
1178                 spin_unlock_bh(&mpath->state_lock);
1179                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1180                         ret = mesh_path_send_to_gates(mpath);
1181                         if (ret)
1182                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1183                 } else
1184                         mesh_path_flush_pending(mpath);
1185         }
1186 }
1187
1188 void
1189 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1190 {
1191         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1192         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1193         u8 flags, target_flags = 0;
1194
1195         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1196                         ? RANN_FLAG_IS_GATE : 0;
1197
1198         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1199         case IEEE80211_PROACTIVE_RANN:
1200                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1201                                cpu_to_le32(++ifmsh->sn),
1202                                0, NULL, 0, broadcast_addr,
1203                                0, ifmsh->mshcfg.element_ttl,
1204                                cpu_to_le32(interval), 0, 0, sdata);
1205                 break;
1206         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1207                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1208         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1209                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1210                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1211                                 IEEE80211_PREQ_USN_FLAG;
1212                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1213                                 cpu_to_le32(++ifmsh->sn), target_flags,
1214                                 (u8 *) broadcast_addr, 0, broadcast_addr,
1215                                 0, ifmsh->mshcfg.element_ttl,
1216                                 cpu_to_le32(interval),
1217                                 0, cpu_to_le32(ifmsh->preq_id++), sdata);
1218                 break;
1219         default:
1220                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1221                 return;
1222         }
1223 }