net/mac80211/mesh_hwmp.c

   1 /*
   2  * Copyright (c) 2008, 2009 open80211s Ltd.
   3  * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/slab.h>
  11 #include <linux/etherdevice.h>
  12 #include <asm/unaligned.h>
  13 #include "wme.h"
  14 #include "mesh.h"
  15
  16 #define TEST_FRAME_LEN  8192
  17 #define MAX_METRIC      0xffffffff
  18 #define ARITH_SHIFT     8
  19
  20 #define MAX_PREQ_QUEUE_LEN      64
  21
  22 /* Destination only */
  23 #define MP_F_DO 0x1
  24 /* Reply and forward */
  25 #define MP_F_RF 0x2
  26 /* Unknown Sequence Number */
  27 #define MP_F_USN    0x01
  28 /* Reason code Present */
  29 #define MP_F_RCODE  0x02
  30
  31 static void mesh_queue_preq(struct mesh_path *, u8);
  32
  33 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
  34 {
  35         if (ae)
  36                 offset += 6;
  37         return get_unaligned_le32(preq_elem + offset);
  38 }
  39
  40 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
  41 {
  42         if (ae)
  43                 offset += 6;
  44         return get_unaligned_le16(preq_elem + offset);
  45 }
  46
  47 /* HWMP IE processing macros */
  48 #define AE_F                    (1<<6)
  49 #define AE_F_SET(x)             (*x & AE_F)
  50 #define PREQ_IE_FLAGS(x)        (*(x))
  51 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  52 #define PREQ_IE_TTL(x)          (*(x + 2))
  53 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  54 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  55 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  56 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  57 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  58 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  59 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  60 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  61
  62
  63 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  64 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  65 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  66 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  67 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  68 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  69 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  70 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  71 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  72
  73 #define PERR_IE_TTL(x)          (*(x))
  74 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  75 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  76 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  77 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  78
  79 #define MSEC_TO_TU(x) (x*1000/1024)
  80 #define SN_GT(x, y) ((s32)(y - x) < 0)
  81 #define SN_LT(x, y) ((s32)(x - y) < 0)
  82
  83 #define net_traversal_jiffies(s) \
  84         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  85 #define default_lifetime(s) \
  86         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  87 #define min_preq_int_jiff(s) \
  88         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  89 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  90 #define disc_timeout_jiff(s) \
  91         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  92 #define root_path_confirmation_jiffies(s) \
  93         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  94
  95 enum mpath_frame_type {
  96         MPATH_PREQ = 0,
  97         MPATH_PREP,
  98         MPATH_PERR,
  99         MPATH_RANN
 100 };
 101
 102 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 103
 104 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 105                 u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
 106                 __le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
 107                 __le32 lifetime, __le32 metric, __le32 preq_id,
 108                 struct ieee80211_sub_if_data *sdata)
 109 {
 110         struct ieee80211_local *local = sdata->local;
 111         struct sk_buff *skb;
 112         struct ieee80211_mgmt *mgmt;
 113         u8 *pos, ie_len;
 114         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 115                       sizeof(mgmt->u.action.u.mesh_action);
 116
 117         skb = dev_alloc_skb(local->tx_headroom +
 118                             hdr_len +
 119                             2 + 37); /* max HWMP IE */
 120         if (!skb)
 121                 return -1;
 122         skb_reserve(skb, local->tx_headroom);
 123         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 124         memset(mgmt, 0, hdr_len);
 125         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 126                                           IEEE80211_STYPE_ACTION);
 127
 128         memcpy(mgmt->da, da, ETH_ALEN);
 129         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 130         /* BSSID == SA */
 131         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 132         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 133         mgmt->u.action.u.mesh_action.action_code =
 134                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 135
 136         switch (action) {
 137         case MPATH_PREQ:
 138                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 139                 ie_len = 37;
 140                 pos = skb_put(skb, 2 + ie_len);
 141                 *pos++ = WLAN_EID_PREQ;
 142                 break;
 143         case MPATH_PREP:
 144                 mhwmp_dbg(sdata, "sending PREP to %pM\n", target);
 145                 ie_len = 31;
 146                 pos = skb_put(skb, 2 + ie_len);
 147                 *pos++ = WLAN_EID_PREP;
 148                 break;
 149         case MPATH_RANN:
 150                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 151                 ie_len = sizeof(struct ieee80211_rann_ie);
 152                 pos = skb_put(skb, 2 + ie_len);
 153                 *pos++ = WLAN_EID_RANN;
 154                 break;
 155         default:
 156                 kfree_skb(skb);
 157                 return -ENOTSUPP;
 158                 break;
 159         }
 160         *pos++ = ie_len;
 161         *pos++ = flags;
 162         *pos++ = hop_count;
 163         *pos++ = ttl;
 164         if (action == MPATH_PREP) {
 165                 memcpy(pos, target, ETH_ALEN);
 166                 pos += ETH_ALEN;
 167                 memcpy(pos, &target_sn, 4);
 168                 pos += 4;
 169         } else {
 170                 if (action == MPATH_PREQ) {
 171                         memcpy(pos, &preq_id, 4);
 172                         pos += 4;
 173                 }
 174                 memcpy(pos, orig_addr, ETH_ALEN);
 175                 pos += ETH_ALEN;
 176                 memcpy(pos, &orig_sn, 4);
 177                 pos += 4;
 178         }
 179         memcpy(pos, &lifetime, 4);      /* interval for RANN */
 180         pos += 4;
 181         memcpy(pos, &metric, 4);
 182         pos += 4;
 183         if (action == MPATH_PREQ) {
 184                 *pos++ = 1; /* destination count */
 185                 *pos++ = target_flags;
 186                 memcpy(pos, target, ETH_ALEN);
 187                 pos += ETH_ALEN;
 188                 memcpy(pos, &target_sn, 4);
 189                 pos += 4;
 190         } else if (action == MPATH_PREP) {
 191                 memcpy(pos, orig_addr, ETH_ALEN);
 192                 pos += ETH_ALEN;
 193                 memcpy(pos, &orig_sn, 4);
 194                 pos += 4;
 195         }
 196
 197         ieee80211_tx_skb(sdata, skb);
 198         return 0;
 199 }
 200
 201
 202 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 203  *  headroom in case the frame is encrypted. */
 204 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 205                 struct sk_buff *skb)
 206 {
 207         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 208
 209         skb_set_mac_header(skb, 0);
 210         skb_set_network_header(skb, 0);
 211         skb_set_transport_header(skb, 0);
 212
 213         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 214         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 215         skb->priority = 7;
 216
 217         info->control.vif = &sdata->vif;
 218         ieee80211_set_qos_hdr(sdata, skb);
 219 }
 220
 221 /**
 222  * mesh_send_path error - Sends a PERR mesh management frame
 223  *
 224  * @target: broken destination
 225  * @target_sn: SN of the broken destination
 226  * @target_rcode: reason code for this PERR
 227  * @ra: node this frame is addressed to
 228  *
 229  * Note: This function may be called with driver locks taken that the driver
 230  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 231  * frame directly but add it to the pending queue instead.
 232  */
 233 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 234                        __le16 target_rcode, const u8 *ra,
 235                        struct ieee80211_sub_if_data *sdata)
 236 {
 237         struct ieee80211_local *local = sdata->local;
 238         struct sk_buff *skb;
 239         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 240         struct ieee80211_mgmt *mgmt;
 241         u8 *pos, ie_len;
 242         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 243                       sizeof(mgmt->u.action.u.mesh_action);
 244
 245         if (time_before(jiffies, ifmsh->next_perr))
 246                 return -EAGAIN;
 247
 248         skb = dev_alloc_skb(local->tx_headroom +
 249                             hdr_len +
 250                             2 + 15 /* PERR IE */);
 251         if (!skb)
 252                 return -1;
 253         skb_reserve(skb, local->tx_headroom);
 254         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 255         memset(mgmt, 0, hdr_len);
 256         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 257                                           IEEE80211_STYPE_ACTION);
 258
 259         memcpy(mgmt->da, ra, ETH_ALEN);
 260         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 261         /* BSSID == SA */
 262         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 263         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 264         mgmt->u.action.u.mesh_action.action_code =
 265                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 266         ie_len = 15;
 267         pos = skb_put(skb, 2 + ie_len);
 268         *pos++ = WLAN_EID_PERR;
 269         *pos++ = ie_len;
 270         /* ttl */
 271         *pos++ = ttl;
 272         /* number of destinations */
 273         *pos++ = 1;
 274         /*
 275          * flags bit, bit 1 is unset if we know the sequence number and
 276          * bit 2 is set if we have a reason code
 277          */
 278         *pos = 0;
 279         if (!target_sn)
 280                 *pos |= MP_F_USN;
 281         if (target_rcode)
 282                 *pos |= MP_F_RCODE;
 283         pos++;
 284         memcpy(pos, target, ETH_ALEN);
 285         pos += ETH_ALEN;
 286         memcpy(pos, &target_sn, 4);
 287         pos += 4;
 288         memcpy(pos, &target_rcode, 2);
 289
 290         /* see note in function header */
 291         prepare_frame_for_deferred_tx(sdata, skb);
 292         ifmsh->next_perr = TU_TO_EXP_TIME(
 293                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 294         ieee80211_add_pending_skb(local, skb);
 295         return 0;
 296 }
 297
 298 void ieee80211s_update_metric(struct ieee80211_local *local,
 299                 struct sta_info *sta, struct sk_buff *skb)
 300 {
 301         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 302         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 303         int failed;
 304
 305         if (!ieee80211_is_data(hdr->frame_control))
 306                 return;
 307
 308         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 309
 310         /* moving average, scaled to 100 */
 311         sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
 312         if (sta->fail_avg > 95)
 313                 mesh_plink_broken(sta);
 314 }
 315
 316 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 317                                    struct sta_info *sta)
 318 {
 319         struct rate_info rinfo;
 320         /* This should be adjusted for each device */
 321         int device_constant = 1 << ARITH_SHIFT;
 322         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 323         int s_unit = 1 << ARITH_SHIFT;
 324         int rate, err;
 325         u32 tx_time, estimated_retx;
 326         u64 result;
 327
 328         if (sta->fail_avg >= 100)
 329                 return MAX_METRIC;
 330
 331         sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
 332         rate = cfg80211_calculate_bitrate(&rinfo);
 333         if (WARN_ON(!rate))
 334                 return MAX_METRIC;
 335
 336         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 337
 338         /* bitrate is in units of 100 Kbps, while we need rate in units of
 339          * 1Mbps. This will be corrected on tx_time computation.
 340          */
 341         tx_time = (device_constant + 10 * test_frame_len / rate);
 342         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 343         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 344         return (u32)result;
 345 }
 346
 347 /**
 348  * hwmp_route_info_get - Update routing info to originator and transmitter
 349  *
 350  * @sdata: local mesh subif
 351  * @mgmt: mesh management frame
 352  * @hwmp_ie: hwmp information element (PREP or PREQ)
 353  *
 354  * This function updates the path routing information to the originator and the
 355  * transmitter of a HWMP PREQ or PREP frame.
 356  *
 357  * Returns: metric to frame originator or 0 if the frame should not be further
 358  * processed
 359  *
 360  * Notes: this function is the only place (besides user-provided info) where
 361  * path routing information is updated.
 362  */
 363 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 364                             struct ieee80211_mgmt *mgmt,
 365                             u8 *hwmp_ie, enum mpath_frame_type action)
 366 {
 367         struct ieee80211_local *local = sdata->local;
 368         struct mesh_path *mpath;
 369         struct sta_info *sta;
 370         bool fresh_info;
 371         u8 *orig_addr, *ta;
 372         u32 orig_sn, orig_metric;
 373         unsigned long orig_lifetime, exp_time;
 374         u32 last_hop_metric, new_metric;
 375         bool process = true;
 376
 377         rcu_read_lock();
 378         sta = sta_info_get(sdata, mgmt->sa);
 379         if (!sta) {
 380                 rcu_read_unlock();
 381                 return 0;
 382         }
 383
 384         last_hop_metric = airtime_link_metric_get(local, sta);
 385         /* Update and check originator routing info */
 386         fresh_info = true;
 387
 388         switch (action) {
 389         case MPATH_PREQ:
 390                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 391                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 392                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 393                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 394                 break;
 395         case MPATH_PREP:
 396                 /* Originator here refers to the MP that was the target in the
 397                  * Path Request. We divert from the nomenclature in the draft
 398                  * so that we can easily use a single function to gather path
 399                  * information from both PREQ and PREP frames.
 400                  */
 401                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 402                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 403                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 404                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 405                 break;
 406         default:
 407                 rcu_read_unlock();
 408                 return 0;
 409         }
 410         new_metric = orig_metric + last_hop_metric;
 411         if (new_metric < orig_metric)
 412                 new_metric = MAX_METRIC;
 413         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 414
 415         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 416                 /* This MP is the originator, we are not interested in this
 417                  * frame, except for updating transmitter's path info.
 418                  */
 419                 process = false;
 420                 fresh_info = false;
 421         } else {
 422                 mpath = mesh_path_lookup(orig_addr, sdata);
 423                 if (mpath) {
 424                         spin_lock_bh(&mpath->state_lock);
 425                         if (mpath->flags & MESH_PATH_FIXED)
 426                                 fresh_info = false;
 427                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 428                             (mpath->flags & MESH_PATH_SN_VALID)) {
 429                                 if (SN_GT(mpath->sn, orig_sn) ||
 430                                     (mpath->sn == orig_sn &&
 431                                      new_metric >= mpath->metric)) {
 432                                         process = false;
 433                                         fresh_info = false;
 434                                 }
 435                         }
 436                 } else {
 437                         mesh_path_add(orig_addr, sdata);
 438                         mpath = mesh_path_lookup(orig_addr, sdata);
 439                         if (!mpath) {
 440                                 rcu_read_unlock();
 441                                 return 0;
 442                         }
 443                         spin_lock_bh(&mpath->state_lock);
 444                 }
 445
 446                 if (fresh_info) {
 447                         mesh_path_assign_nexthop(mpath, sta);
 448                         mpath->flags |= MESH_PATH_SN_VALID;
 449                         mpath->metric = new_metric;
 450                         mpath->sn = orig_sn;
 451                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 452                                           ?  mpath->exp_time : exp_time;
 453                         mesh_path_activate(mpath);
 454                         spin_unlock_bh(&mpath->state_lock);
 455                         mesh_path_tx_pending(mpath);
 456                         /* draft says preq_id should be saved to, but there does
 457                          * not seem to be any use for it, skipping by now
 458                          */
 459                 } else
 460                         spin_unlock_bh(&mpath->state_lock);
 461         }
 462
 463         /* Update and check transmitter routing info */
 464         ta = mgmt->sa;
 465         if (ether_addr_equal(orig_addr, ta))
 466                 fresh_info = false;
 467         else {
 468                 fresh_info = true;
 469
 470                 mpath = mesh_path_lookup(ta, sdata);
 471                 if (mpath) {
 472                         spin_lock_bh(&mpath->state_lock);
 473                         if ((mpath->flags & MESH_PATH_FIXED) ||
 474                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 475                                         (last_hop_metric > mpath->metric)))
 476                                 fresh_info = false;
 477                 } else {
 478                         mesh_path_add(ta, sdata);
 479                         mpath = mesh_path_lookup(ta, sdata);
 480                         if (!mpath) {
 481                                 rcu_read_unlock();
 482                                 return 0;
 483                         }
 484                         spin_lock_bh(&mpath->state_lock);
 485                 }
 486
 487                 if (fresh_info) {
 488                         mesh_path_assign_nexthop(mpath, sta);
 489                         mpath->metric = last_hop_metric;
 490                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 491                                           ?  mpath->exp_time : exp_time;
 492                         mesh_path_activate(mpath);
 493                         spin_unlock_bh(&mpath->state_lock);
 494                         mesh_path_tx_pending(mpath);
 495                 } else
 496                         spin_unlock_bh(&mpath->state_lock);
 497         }
 498
 499         rcu_read_unlock();
 500
 501         return process ? new_metric : 0;
 502 }
 503
 504 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 505                                     struct ieee80211_mgmt *mgmt,
 506                                     u8 *preq_elem, u32 metric)
 507 {
 508         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 509         struct mesh_path *mpath = NULL;
 510         u8 *target_addr, *orig_addr;
 511         const u8 *da;
 512         u8 target_flags, ttl, flags;
 513         u32 orig_sn, target_sn, lifetime, orig_metric;
 514         bool reply = false;
 515         bool forward = true;
 516         bool root_is_gate;
 517
 518         /* Update target SN, if present */
 519         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 520         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 521         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 522         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 523         target_flags = PREQ_IE_TARGET_F(preq_elem);
 524         orig_metric = metric;
 525         /* Proactive PREQ gate announcements */
 526         flags = PREQ_IE_FLAGS(preq_elem);
 527         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 528
 529         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 530
 531         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 532                 mhwmp_dbg(sdata, "PREQ is for us\n");
 533                 forward = false;
 534                 reply = true;
 535                 metric = 0;
 536                 if (time_after(jiffies, ifmsh->last_sn_update +
 537                                         net_traversal_jiffies(sdata)) ||
 538                     time_before(jiffies, ifmsh->last_sn_update)) {
 539                         target_sn = ++ifmsh->sn;
 540                         ifmsh->last_sn_update = jiffies;
 541                 }
 542         } else if (is_broadcast_ether_addr(target_addr) &&
 543                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 544                 rcu_read_lock();
 545                 mpath = mesh_path_lookup(orig_addr, sdata);
 546                 if (mpath) {
 547                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 548                                 reply = true;
 549                                 target_addr = sdata->vif.addr;
 550                                 target_sn = ++ifmsh->sn;
 551                                 metric = 0;
 552                                 ifmsh->last_sn_update = jiffies;
 553                         }
 554                         if (root_is_gate)
 555                                 mesh_path_add_gate(mpath);
 556                 }
 557                 rcu_read_unlock();
 558         } else {
 559                 rcu_read_lock();
 560                 mpath = mesh_path_lookup(target_addr, sdata);
 561                 if (mpath) {
 562                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 563                                         SN_LT(mpath->sn, target_sn)) {
 564                                 mpath->sn = target_sn;
 565                                 mpath->flags |= MESH_PATH_SN_VALID;
 566                         } else if ((!(target_flags & MP_F_DO)) &&
 567                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 568                                 reply = true;
 569                                 metric = mpath->metric;
 570                                 target_sn = mpath->sn;
 571                                 if (target_flags & MP_F_RF)
 572                                         target_flags |= MP_F_DO;
 573                                 else
 574                                         forward = false;
 575                         }
 576                 }
 577                 rcu_read_unlock();
 578         }
 579
 580         if (reply) {
 581                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 582                 ttl = ifmsh->mshcfg.element_ttl;
 583                 if (ttl != 0) {
 584                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 585                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 586                                 cpu_to_le32(orig_sn), 0, target_addr,
 587                                 cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 588                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 589                                 0, sdata);
 590                 } else {
 591                         ifmsh->mshstats.dropped_frames_ttl++;
 592                 }
 593         }
 594
 595         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 596                 u32 preq_id;
 597                 u8 hopcount;
 598
 599                 ttl = PREQ_IE_TTL(preq_elem);
 600                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 601                 if (ttl <= 1) {
 602                         ifmsh->mshstats.dropped_frames_ttl++;
 603                         return;
 604                 }
 605                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 606                 --ttl;
 607                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 608                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 609                 da = (mpath && mpath->is_root) ?
 610                         mpath->rann_snd_addr : broadcast_addr;
 611
 612                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 613                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 614                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 615                         metric = orig_metric;
 616                 }
 617
 618                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 619                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 620                                 cpu_to_le32(target_sn), da,
 621                                 hopcount, ttl, cpu_to_le32(lifetime),
 622                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 623                                 sdata);
 624                 if (!is_multicast_ether_addr(da))
 625                         ifmsh->mshstats.fwded_unicast++;
 626                 else
 627                         ifmsh->mshstats.fwded_mcast++;
 628                 ifmsh->mshstats.fwded_frames++;
 629         }
 630 }
 631
 632
 633 static inline struct sta_info *
 634 next_hop_deref_protected(struct mesh_path *mpath)
 635 {
 636         return rcu_dereference_protected(mpath->next_hop,
 637                                          lockdep_is_held(&mpath->state_lock));
 638 }
 639
 640
 641 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 642                                     struct ieee80211_mgmt *mgmt,
 643                                     u8 *prep_elem, u32 metric)
 644 {
 645         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 646         struct mesh_path *mpath;
 647         u8 *target_addr, *orig_addr;
 648         u8 ttl, hopcount, flags;
 649         u8 next_hop[ETH_ALEN];
 650         u32 target_sn, orig_sn, lifetime;
 651
 652         mhwmp_dbg(sdata, "received PREP from %pM\n",
 653                   PREP_IE_ORIG_ADDR(prep_elem));
 654
 655         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 656         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 657                 /* destination, no forwarding required */
 658                 return;
 659
 660         if (!ifmsh->mshcfg.dot11MeshForwarding)
 661                 return;
 662
 663         ttl = PREP_IE_TTL(prep_elem);
 664         if (ttl <= 1) {
 665                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 666                 return;
 667         }
 668
 669         rcu_read_lock();
 670         mpath = mesh_path_lookup(orig_addr, sdata);
 671         if (mpath)
 672                 spin_lock_bh(&mpath->state_lock);
 673         else
 674                 goto fail;
 675         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 676                 spin_unlock_bh(&mpath->state_lock);
 677                 goto fail;
 678         }
 679         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 680         spin_unlock_bh(&mpath->state_lock);
 681         --ttl;
 682         flags = PREP_IE_FLAGS(prep_elem);
 683         lifetime = PREP_IE_LIFETIME(prep_elem);
 684         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 685         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 686         target_sn = PREP_IE_TARGET_SN(prep_elem);
 687         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 688
 689         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 690                 cpu_to_le32(orig_sn), 0, target_addr,
 691                 cpu_to_le32(target_sn), next_hop, hopcount,
 692                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 693                 0, sdata);
 694         rcu_read_unlock();
 695
 696         sdata->u.mesh.mshstats.fwded_unicast++;
 697         sdata->u.mesh.mshstats.fwded_frames++;
 698         return;
 699
 700 fail:
 701         rcu_read_unlock();
 702         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 703 }
 704
 705 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 706                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 707 {
 708         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 709         struct mesh_path *mpath;
 710         u8 ttl;
 711         u8 *ta, *target_addr;
 712         u32 target_sn;
 713         u16 target_rcode;
 714
 715         ta = mgmt->sa;
 716         ttl = PERR_IE_TTL(perr_elem);
 717         if (ttl <= 1) {
 718                 ifmsh->mshstats.dropped_frames_ttl++;
 719                 return;
 720         }
 721         ttl--;
 722         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 723         target_sn = PERR_IE_TARGET_SN(perr_elem);
 724         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 725
 726         rcu_read_lock();
 727         mpath = mesh_path_lookup(target_addr, sdata);
 728         if (mpath) {
 729                 struct sta_info *sta;
 730
 731                 spin_lock_bh(&mpath->state_lock);
 732                 sta = next_hop_deref_protected(mpath);
 733                 if (mpath->flags & MESH_PATH_ACTIVE &&
 734                     ether_addr_equal(ta, sta->sta.addr) &&
 735                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 736                     SN_GT(target_sn, mpath->sn))) {
 737                         mpath->flags &= ~MESH_PATH_ACTIVE;
 738                         mpath->sn = target_sn;
 739                         spin_unlock_bh(&mpath->state_lock);
 740                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 741                                 goto endperr;
 742                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 743                                            cpu_to_le16(target_rcode),
 744                                            broadcast_addr, sdata);
 745                 } else
 746                         spin_unlock_bh(&mpath->state_lock);
 747         }
 748 endperr:
 749         rcu_read_unlock();
 750 }
 751
 752 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 753                                 struct ieee80211_mgmt *mgmt,
 754                                 struct ieee80211_rann_ie *rann)
 755 {
 756         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 757         struct ieee80211_local *local = sdata->local;
 758         struct sta_info *sta;
 759         struct mesh_path *mpath;
 760         u8 ttl, flags, hopcount;
 761         u8 *orig_addr;
 762         u32 orig_sn, metric, metric_txsta, interval;
 763         bool root_is_gate;
 764
 765         ttl = rann->rann_ttl;
 766         flags = rann->rann_flags;
 767         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 768         orig_addr = rann->rann_addr;
 769         orig_sn = le32_to_cpu(rann->rann_seq);
 770         interval = le32_to_cpu(rann->rann_interval);
 771         hopcount = rann->rann_hopcount;
 772         hopcount++;
 773         metric = le32_to_cpu(rann->rann_metric);
 774
 775         /*  Ignore our own RANNs */
 776         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 777                 return;
 778
 779         mhwmp_dbg(sdata,
 780                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 781                   orig_addr, mgmt->sa, root_is_gate);
 782
 783         rcu_read_lock();
 784         sta = sta_info_get(sdata, mgmt->sa);
 785         if (!sta) {
 786                 rcu_read_unlock();
 787                 return;
 788         }
 789
 790         metric_txsta = airtime_link_metric_get(local, sta);
 791
 792         mpath = mesh_path_lookup(orig_addr, sdata);
 793         if (!mpath) {
 794                 mesh_path_add(orig_addr, sdata);
 795                 mpath = mesh_path_lookup(orig_addr, sdata);
 796                 if (!mpath) {
 797                         rcu_read_unlock();
 798                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 799                         return;
 800                 }
 801         }
 802
 803         if (!(SN_LT(mpath->sn, orig_sn)) &&
 804             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 805                 rcu_read_unlock();
 806                 return;
 807         }
 808
 809         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 810              (time_after(jiffies, mpath->last_preq_to_root +
 811                                   root_path_confirmation_jiffies(sdata)) ||
 812              time_before(jiffies, mpath->last_preq_to_root))) &&
 813              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 814                 mhwmp_dbg(sdata,
 815                           "time to refresh root mpath %pM\n",
 816                           orig_addr);
 817                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 818                 mpath->last_preq_to_root = jiffies;
 819         }
 820
 821         mpath->sn = orig_sn;
 822         mpath->rann_metric = metric + metric_txsta;
 823         mpath->is_root = true;
 824         /* Recording RANNs sender address to send individually
 825          * addressed PREQs destined for root mesh STA */
 826         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 827
 828         if (root_is_gate)
 829                 mesh_path_add_gate(mpath);
 830
 831         if (ttl <= 1) {
 832                 ifmsh->mshstats.dropped_frames_ttl++;
 833                 rcu_read_unlock();
 834                 return;
 835         }
 836         ttl--;
 837
 838         if (ifmsh->mshcfg.dot11MeshForwarding) {
 839                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 840                                        cpu_to_le32(orig_sn),
 841                                        0, NULL, 0, broadcast_addr,
 842                                        hopcount, ttl, cpu_to_le32(interval),
 843                                        cpu_to_le32(metric + metric_txsta),
 844                                        0, sdata);
 845         }
 846
 847         rcu_read_unlock();
 848 }
 849
 850
 851 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 852                             struct ieee80211_mgmt *mgmt,
 853                             size_t len)
 854 {
 855         struct ieee802_11_elems elems;
 856         size_t baselen;
 857         u32 last_hop_metric;
 858         struct sta_info *sta;
 859
 860         /* need action_code */
 861         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 862                 return;
 863
 864         rcu_read_lock();
 865         sta = sta_info_get(sdata, mgmt->sa);
 866         if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 867                 rcu_read_unlock();
 868                 return;
 869         }
 870         rcu_read_unlock();
 871
 872         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 873         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 874                         len - baselen, &elems);
 875
 876         if (elems.preq) {
 877                 if (elems.preq_len != 37)
 878                         /* Right now we support just 1 destination and no AE */
 879                         return;
 880                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 881                                                       MPATH_PREQ);
 882                 if (last_hop_metric)
 883                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 884                                                 last_hop_metric);
 885         }
 886         if (elems.prep) {
 887                 if (elems.prep_len != 31)
 888                         /* Right now we support no AE */
 889                         return;
 890                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 891                                                       MPATH_PREP);
 892                 if (last_hop_metric)
 893                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 894                                                 last_hop_metric);
 895         }
 896         if (elems.perr) {
 897                 if (elems.perr_len != 15)
 898                         /* Right now we support only one destination per PERR */
 899                         return;
 900                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 901         }
 902         if (elems.rann)
 903                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 904 }
 905
 906 /**
 907  * mesh_queue_preq - queue a PREQ to a given destination
 908  *
 909  * @mpath: mesh path to discover
 910  * @flags: special attributes of the PREQ to be sent
 911  *
 912  * Locking: the function must be called from within a rcu read lock block.
 913  *
 914  */
 915 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 916 {
 917         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 918         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 919         struct mesh_preq_queue *preq_node;
 920
 921         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 922         if (!preq_node) {
 923                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 924                 return;
 925         }
 926
 927         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 928         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 929                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 930                 kfree(preq_node);
 931                 if (printk_ratelimit())
 932                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 933                 return;
 934         }
 935
 936         spin_lock(&mpath->state_lock);
 937         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 938                 spin_unlock(&mpath->state_lock);
 939                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 940                 kfree(preq_node);
 941                 return;
 942         }
 943
 944         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 945         preq_node->flags = flags;
 946
 947         mpath->flags |= MESH_PATH_REQ_QUEUED;
 948         spin_unlock(&mpath->state_lock);
 949
 950         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 951         ++ifmsh->preq_queue_len;
 952         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 953
 954         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 955                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 956
 957         else if (time_before(jiffies, ifmsh->last_preq)) {
 958                 /* avoid long wait if did not send preqs for a long time
 959                  * and jiffies wrapped around
 960                  */
 961                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 962                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 963         } else
 964                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 965                                                 min_preq_int_jiff(sdata));
 966 }
 967
 968 /**
 969  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 970  *
 971  * @sdata: local mesh subif
 972  */
 973 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 974 {
 975         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 976         struct mesh_preq_queue *preq_node;
 977         struct mesh_path *mpath;
 978         u8 ttl, target_flags;
 979         const u8 *da;
 980         u32 lifetime;
 981
 982         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 983         if (!ifmsh->preq_queue_len ||
 984                 time_before(jiffies, ifmsh->last_preq +
 985                                 min_preq_int_jiff(sdata))) {
 986                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 987                 return;
 988         }
 989
 990         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 991                         struct mesh_preq_queue, list);
 992         list_del(&preq_node->list);
 993         --ifmsh->preq_queue_len;
 994         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 995
 996         rcu_read_lock();
 997         mpath = mesh_path_lookup(preq_node->dst, sdata);
 998         if (!mpath)
 999                 goto enddiscovery;
1000
1001         spin_lock_bh(&mpath->state_lock);
1002         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1003         if (preq_node->flags & PREQ_Q_F_START) {
1004                 if (mpath->flags & MESH_PATH_RESOLVING) {
1005                         spin_unlock_bh(&mpath->state_lock);
1006                         goto enddiscovery;
1007                 } else {
1008                         mpath->flags &= ~MESH_PATH_RESOLVED;
1009                         mpath->flags |= MESH_PATH_RESOLVING;
1010                         mpath->discovery_retries = 0;
1011                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1012                 }
1013         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1014                         mpath->flags & MESH_PATH_RESOLVED) {
1015                 mpath->flags &= ~MESH_PATH_RESOLVING;
1016                 spin_unlock_bh(&mpath->state_lock);
1017                 goto enddiscovery;
1018         }
1019
1020         ifmsh->last_preq = jiffies;
1021
1022         if (time_after(jiffies, ifmsh->last_sn_update +
1023                                 net_traversal_jiffies(sdata)) ||
1024             time_before(jiffies, ifmsh->last_sn_update)) {
1025                 ++ifmsh->sn;
1026                 sdata->u.mesh.last_sn_update = jiffies;
1027         }
1028         lifetime = default_lifetime(sdata);
1029         ttl = sdata->u.mesh.mshcfg.element_ttl;
1030         if (ttl == 0) {
1031                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1032                 spin_unlock_bh(&mpath->state_lock);
1033                 goto enddiscovery;
1034         }
1035
1036         if (preq_node->flags & PREQ_Q_F_REFRESH)
1037                 target_flags = MP_F_DO;
1038         else
1039                 target_flags = MP_F_RF;
1040
1041         spin_unlock_bh(&mpath->state_lock);
1042         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1043         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1044                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1045                         cpu_to_le32(mpath->sn), da, 0,
1046                         ttl, cpu_to_le32(lifetime), 0,
1047                         cpu_to_le32(ifmsh->preq_id++), sdata);
1048         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1049
1050 enddiscovery:
1051         rcu_read_unlock();
1052         kfree(preq_node);
1053 }
1054
1055 /**
1056  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1057  *
1058  * @skb: 802.11 frame to be sent
1059  * @sdata: network subif the frame will be sent through
1060  *
1061  * Lookup next hop for given skb and start path discovery if no
1062  * forwarding information is found.
1063  *
1064  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1065  * skb is freeed here if no mpath could be allocated.
1066  */
1067 int mesh_nexthop_resolve(struct sk_buff *skb,
1068                          struct ieee80211_sub_if_data *sdata)
1069 {
1070         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1071         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1072         struct mesh_path *mpath;
1073         struct sk_buff *skb_to_free = NULL;
1074         u8 *target_addr = hdr->addr3;
1075         int err = 0;
1076
1077         rcu_read_lock();
1078         err = mesh_nexthop_lookup(skb, sdata);
1079         if (!err)
1080                 goto endlookup;
1081
1082         /* no nexthop found, start resolving */
1083         mpath = mesh_path_lookup(target_addr, sdata);
1084         if (!mpath) {
1085                 mesh_path_add(target_addr, sdata);
1086                 mpath = mesh_path_lookup(target_addr, sdata);
1087                 if (!mpath) {
1088                         mesh_path_discard_frame(skb, sdata);
1089                         err = -ENOSPC;
1090                         goto endlookup;
1091                 }
1092         }
1093
1094         if (!(mpath->flags & MESH_PATH_RESOLVING))
1095                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1096
1097         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1098                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1099
1100         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1101         ieee80211_set_qos_hdr(sdata, skb);
1102         skb_queue_tail(&mpath->frame_queue, skb);
1103         err = -ENOENT;
1104         if (skb_to_free)
1105                 mesh_path_discard_frame(skb_to_free, sdata);
1106
1107 endlookup:
1108         rcu_read_unlock();
1109         return err;
1110 }
1111 /**
1112  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1113  * this function is considered "using" the associated mpath, so preempt a path
1114  * refresh if this mpath expires soon.
1115  *
1116  * @skb: 802.11 frame to be sent
1117  * @sdata: network subif the frame will be sent through
1118  *
1119  * Returns: 0 if the next hop was found. Nonzero otherwise.
1120  */
1121 int mesh_nexthop_lookup(struct sk_buff *skb,
1122                         struct ieee80211_sub_if_data *sdata)
1123 {
1124         struct mesh_path *mpath;
1125         struct sta_info *next_hop;
1126         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1127         u8 *target_addr = hdr->addr3;
1128         int err = -ENOENT;
1129
1130         rcu_read_lock();
1131         mpath = mesh_path_lookup(target_addr, sdata);
1132
1133         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1134                 goto endlookup;
1135
1136         if (time_after(jiffies,
1137                        mpath->exp_time -
1138                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1139             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1140             !(mpath->flags & MESH_PATH_RESOLVING) &&
1141             !(mpath->flags & MESH_PATH_FIXED))
1142                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1143
1144         next_hop = rcu_dereference(mpath->next_hop);
1145         if (next_hop) {
1146                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1147                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1148                 err = 0;
1149         }
1150
1151 endlookup:
1152         rcu_read_unlock();
1153         return err;
1154 }
1155
1156 void mesh_path_timer(unsigned long data)
1157 {
1158         struct mesh_path *mpath = (void *) data;
1159         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1160         int ret;
1161
1162         if (sdata->local->quiescing)
1163                 return;
1164
1165         spin_lock_bh(&mpath->state_lock);
1166         if (mpath->flags & MESH_PATH_RESOLVED ||
1167                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1168                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1169                 spin_unlock_bh(&mpath->state_lock);
1170         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1171                 ++mpath->discovery_retries;
1172                 mpath->discovery_timeout *= 2;
1173                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1174                 spin_unlock_bh(&mpath->state_lock);
1175                 mesh_queue_preq(mpath, 0);
1176         } else {
1177                 mpath->flags = 0;
1178                 mpath->exp_time = jiffies;
1179                 spin_unlock_bh(&mpath->state_lock);
1180                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1181                         ret = mesh_path_send_to_gates(mpath);
1182                         if (ret)
1183                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1184                 } else
1185                         mesh_path_flush_pending(mpath);
1186         }
1187 }
1188
1189 void
1190 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1191 {
1192         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1193         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1194         u8 flags, target_flags = 0;
1195
1196         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1197                         ? RANN_FLAG_IS_GATE : 0;
1198
1199         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1200         case IEEE80211_PROACTIVE_RANN:
1201                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1202                                cpu_to_le32(++ifmsh->sn),
1203                                0, NULL, 0, broadcast_addr,
1204                                0, ifmsh->mshcfg.element_ttl,
1205                                cpu_to_le32(interval), 0, 0, sdata);
1206                 break;
1207         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1208                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1209         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1210                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1211                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1212                                 IEEE80211_PREQ_USN_FLAG;
1213                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1214                                 cpu_to_le32(++ifmsh->sn), target_flags,
1215                                 (u8 *) broadcast_addr, 0, broadcast_addr,
1216                                 0, ifmsh->mshcfg.element_ttl,
1217                                 cpu_to_le32(interval),
1218                                 0, cpu_to_le32(ifmsh->preq_id++), sdata);
1219                 break;
1220         default:
1221                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1222                 return;
1223         }
1224 }