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         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 219         ieee80211_set_qos_hdr(sdata, skb);
 220 }
 221
 222 /**
 223  * mesh_send_path error - Sends a PERR mesh management frame
 224  *
 225  * @target: broken destination
 226  * @target_sn: SN of the broken destination
 227  * @target_rcode: reason code for this PERR
 228  * @ra: node this frame is addressed to
 229  *
 230  * Note: This function may be called with driver locks taken that the driver
 231  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 232  * frame directly but add it to the pending queue instead.
 233  */
 234 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 235                        __le16 target_rcode, const u8 *ra,
 236                        struct ieee80211_sub_if_data *sdata)
 237 {
 238         struct ieee80211_local *local = sdata->local;
 239         struct sk_buff *skb;
 240         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 241         struct ieee80211_mgmt *mgmt;
 242         u8 *pos, ie_len;
 243         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 244                       sizeof(mgmt->u.action.u.mesh_action);
 245
 246         if (time_before(jiffies, ifmsh->next_perr))
 247                 return -EAGAIN;
 248
 249         skb = dev_alloc_skb(local->tx_headroom +
 250                             hdr_len +
 251                             2 + 15 /* PERR IE */);
 252         if (!skb)
 253                 return -1;
 254         skb_reserve(skb, local->tx_headroom);
 255         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 256         memset(mgmt, 0, hdr_len);
 257         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 258                                           IEEE80211_STYPE_ACTION);
 259
 260         memcpy(mgmt->da, ra, ETH_ALEN);
 261         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 262         /* BSSID == SA */
 263         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 264         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 265         mgmt->u.action.u.mesh_action.action_code =
 266                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 267         ie_len = 15;
 268         pos = skb_put(skb, 2 + ie_len);
 269         *pos++ = WLAN_EID_PERR;
 270         *pos++ = ie_len;
 271         /* ttl */
 272         *pos++ = ttl;
 273         /* number of destinations */
 274         *pos++ = 1;
 275         /*
 276          * flags bit, bit 1 is unset if we know the sequence number and
 277          * bit 2 is set if we have a reason code
 278          */
 279         *pos = 0;
 280         if (!target_sn)
 281                 *pos |= MP_F_USN;
 282         if (target_rcode)
 283                 *pos |= MP_F_RCODE;
 284         pos++;
 285         memcpy(pos, target, ETH_ALEN);
 286         pos += ETH_ALEN;
 287         memcpy(pos, &target_sn, 4);
 288         pos += 4;
 289         memcpy(pos, &target_rcode, 2);
 290
 291         /* see note in function header */
 292         prepare_frame_for_deferred_tx(sdata, skb);
 293         ifmsh->next_perr = TU_TO_EXP_TIME(
 294                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 295         ieee80211_add_pending_skb(local, skb);
 296         return 0;
 297 }
 298
 299 void ieee80211s_update_metric(struct ieee80211_local *local,
 300                 struct sta_info *sta, struct sk_buff *skb)
 301 {
 302         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 303         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 304         int failed;
 305
 306         if (!ieee80211_is_data(hdr->frame_control))
 307                 return;
 308
 309         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 310
 311         /* moving average, scaled to 100 */
 312         sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
 313         if (sta->fail_avg > 95)
 314                 mesh_plink_broken(sta);
 315 }
 316
 317 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 318                                    struct sta_info *sta)
 319 {
 320         struct rate_info rinfo;
 321         /* This should be adjusted for each device */
 322         int device_constant = 1 << ARITH_SHIFT;
 323         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 324         int s_unit = 1 << ARITH_SHIFT;
 325         int rate, err;
 326         u32 tx_time, estimated_retx;
 327         u64 result;
 328
 329         if (sta->fail_avg >= 100)
 330                 return MAX_METRIC;
 331
 332         sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
 333         rate = cfg80211_calculate_bitrate(&rinfo);
 334         if (WARN_ON(!rate))
 335                 return MAX_METRIC;
 336
 337         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 338
 339         /* bitrate is in units of 100 Kbps, while we need rate in units of
 340          * 1Mbps. This will be corrected on tx_time computation.
 341          */
 342         tx_time = (device_constant + 10 * test_frame_len / rate);
 343         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 344         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 345         return (u32)result;
 346 }
 347
 348 /**
 349  * hwmp_route_info_get - Update routing info to originator and transmitter
 350  *
 351  * @sdata: local mesh subif
 352  * @mgmt: mesh management frame
 353  * @hwmp_ie: hwmp information element (PREP or PREQ)
 354  *
 355  * This function updates the path routing information to the originator and the
 356  * transmitter of a HWMP PREQ or PREP frame.
 357  *
 358  * Returns: metric to frame originator or 0 if the frame should not be further
 359  * processed
 360  *
 361  * Notes: this function is the only place (besides user-provided info) where
 362  * path routing information is updated.
 363  */
 364 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 365                             struct ieee80211_mgmt *mgmt,
 366                             u8 *hwmp_ie, enum mpath_frame_type action)
 367 {
 368         struct ieee80211_local *local = sdata->local;
 369         struct mesh_path *mpath;
 370         struct sta_info *sta;
 371         bool fresh_info;
 372         u8 *orig_addr, *ta;
 373         u32 orig_sn, orig_metric;
 374         unsigned long orig_lifetime, exp_time;
 375         u32 last_hop_metric, new_metric;
 376         bool process = true;
 377
 378         rcu_read_lock();
 379         sta = sta_info_get(sdata, mgmt->sa);
 380         if (!sta) {
 381                 rcu_read_unlock();
 382                 return 0;
 383         }
 384
 385         last_hop_metric = airtime_link_metric_get(local, sta);
 386         /* Update and check originator routing info */
 387         fresh_info = true;
 388
 389         switch (action) {
 390         case MPATH_PREQ:
 391                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 392                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 393                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 394                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 395                 break;
 396         case MPATH_PREP:
 397                 /* Originator here refers to the MP that was the target in the
 398                  * Path Request. We divert from the nomenclature in the draft
 399                  * so that we can easily use a single function to gather path
 400                  * information from both PREQ and PREP frames.
 401                  */
 402                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 403                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 404                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 405                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 406                 break;
 407         default:
 408                 rcu_read_unlock();
 409                 return 0;
 410         }
 411         new_metric = orig_metric + last_hop_metric;
 412         if (new_metric < orig_metric)
 413                 new_metric = MAX_METRIC;
 414         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 415
 416         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 417                 /* This MP is the originator, we are not interested in this
 418                  * frame, except for updating transmitter's path info.
 419                  */
 420                 process = false;
 421                 fresh_info = false;
 422         } else {
 423                 mpath = mesh_path_lookup(orig_addr, sdata);
 424                 if (mpath) {
 425                         spin_lock_bh(&mpath->state_lock);
 426                         if (mpath->flags & MESH_PATH_FIXED)
 427                                 fresh_info = false;
 428                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 429                             (mpath->flags & MESH_PATH_SN_VALID)) {
 430                                 if (SN_GT(mpath->sn, orig_sn) ||
 431                                     (mpath->sn == orig_sn &&
 432                                      new_metric >= mpath->metric)) {
 433                                         process = false;
 434                                         fresh_info = false;
 435                                 }
 436                         }
 437                 } else {
 438                         mesh_path_add(orig_addr, sdata);
 439                         mpath = mesh_path_lookup(orig_addr, sdata);
 440                         if (!mpath) {
 441                                 rcu_read_unlock();
 442                                 return 0;
 443                         }
 444                         spin_lock_bh(&mpath->state_lock);
 445                 }
 446
 447                 if (fresh_info) {
 448                         mesh_path_assign_nexthop(mpath, sta);
 449                         mpath->flags |= MESH_PATH_SN_VALID;
 450                         mpath->metric = new_metric;
 451                         mpath->sn = orig_sn;
 452                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 453                                           ?  mpath->exp_time : exp_time;
 454                         mesh_path_activate(mpath);
 455                         spin_unlock_bh(&mpath->state_lock);
 456                         mesh_path_tx_pending(mpath);
 457                         /* draft says preq_id should be saved to, but there does
 458                          * not seem to be any use for it, skipping by now
 459                          */
 460                 } else
 461                         spin_unlock_bh(&mpath->state_lock);
 462         }
 463
 464         /* Update and check transmitter routing info */
 465         ta = mgmt->sa;
 466         if (ether_addr_equal(orig_addr, ta))
 467                 fresh_info = false;
 468         else {
 469                 fresh_info = true;
 470
 471                 mpath = mesh_path_lookup(ta, sdata);
 472                 if (mpath) {
 473                         spin_lock_bh(&mpath->state_lock);
 474                         if ((mpath->flags & MESH_PATH_FIXED) ||
 475                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 476                                         (last_hop_metric > mpath->metric)))
 477                                 fresh_info = false;
 478                 } else {
 479                         mesh_path_add(ta, sdata);
 480                         mpath = mesh_path_lookup(ta, sdata);
 481                         if (!mpath) {
 482                                 rcu_read_unlock();
 483                                 return 0;
 484                         }
 485                         spin_lock_bh(&mpath->state_lock);
 486                 }
 487
 488                 if (fresh_info) {
 489                         mesh_path_assign_nexthop(mpath, sta);
 490                         mpath->metric = last_hop_metric;
 491                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 492                                           ?  mpath->exp_time : exp_time;
 493                         mesh_path_activate(mpath);
 494                         spin_unlock_bh(&mpath->state_lock);
 495                         mesh_path_tx_pending(mpath);
 496                 } else
 497                         spin_unlock_bh(&mpath->state_lock);
 498         }
 499
 500         rcu_read_unlock();
 501
 502         return process ? new_metric : 0;
 503 }
 504
 505 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 506                                     struct ieee80211_mgmt *mgmt,
 507                                     u8 *preq_elem, u32 metric)
 508 {
 509         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 510         struct mesh_path *mpath = NULL;
 511         u8 *target_addr, *orig_addr;
 512         const u8 *da;
 513         u8 target_flags, ttl, flags;
 514         u32 orig_sn, target_sn, lifetime, orig_metric;
 515         bool reply = false;
 516         bool forward = true;
 517         bool root_is_gate;
 518
 519         /* Update target SN, if present */
 520         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 521         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 522         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 523         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 524         target_flags = PREQ_IE_TARGET_F(preq_elem);
 525         orig_metric = metric;
 526         /* Proactive PREQ gate announcements */
 527         flags = PREQ_IE_FLAGS(preq_elem);
 528         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 529
 530         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 531
 532         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 533                 mhwmp_dbg(sdata, "PREQ is for us\n");
 534                 forward = false;
 535                 reply = true;
 536                 metric = 0;
 537                 if (time_after(jiffies, ifmsh->last_sn_update +
 538                                         net_traversal_jiffies(sdata)) ||
 539                     time_before(jiffies, ifmsh->last_sn_update)) {
 540                         target_sn = ++ifmsh->sn;
 541                         ifmsh->last_sn_update = jiffies;
 542                 }
 543         } else if (is_broadcast_ether_addr(target_addr) &&
 544                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 545                 rcu_read_lock();
 546                 mpath = mesh_path_lookup(orig_addr, sdata);
 547                 if (mpath) {
 548                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 549                                 reply = true;
 550                                 target_addr = sdata->vif.addr;
 551                                 target_sn = ++ifmsh->sn;
 552                                 metric = 0;
 553                                 ifmsh->last_sn_update = jiffies;
 554                         }
 555                         if (root_is_gate)
 556                                 mesh_path_add_gate(mpath);
 557                 }
 558                 rcu_read_unlock();
 559         } else {
 560                 rcu_read_lock();
 561                 mpath = mesh_path_lookup(target_addr, sdata);
 562                 if (mpath) {
 563                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 564                                         SN_LT(mpath->sn, target_sn)) {
 565                                 mpath->sn = target_sn;
 566                                 mpath->flags |= MESH_PATH_SN_VALID;
 567                         } else if ((!(target_flags & MP_F_DO)) &&
 568                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 569                                 reply = true;
 570                                 metric = mpath->metric;
 571                                 target_sn = mpath->sn;
 572                                 if (target_flags & MP_F_RF)
 573                                         target_flags |= MP_F_DO;
 574                                 else
 575                                         forward = false;
 576                         }
 577                 }
 578                 rcu_read_unlock();
 579         }
 580
 581         if (reply) {
 582                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 583                 ttl = ifmsh->mshcfg.element_ttl;
 584                 if (ttl != 0) {
 585                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 586                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 587                                 cpu_to_le32(orig_sn), 0, target_addr,
 588                                 cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 589                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 590                                 0, sdata);
 591                 } else {
 592                         ifmsh->mshstats.dropped_frames_ttl++;
 593                 }
 594         }
 595
 596         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 597                 u32 preq_id;
 598                 u8 hopcount;
 599
 600                 ttl = PREQ_IE_TTL(preq_elem);
 601                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 602                 if (ttl <= 1) {
 603                         ifmsh->mshstats.dropped_frames_ttl++;
 604                         return;
 605                 }
 606                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 607                 --ttl;
 608                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 609                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 610                 da = (mpath && mpath->is_root) ?
 611                         mpath->rann_snd_addr : broadcast_addr;
 612
 613                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 614                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 615                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 616                         metric = orig_metric;
 617                 }
 618
 619                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 620                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 621                                 cpu_to_le32(target_sn), da,
 622                                 hopcount, ttl, cpu_to_le32(lifetime),
 623                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 624                                 sdata);
 625                 if (!is_multicast_ether_addr(da))
 626                         ifmsh->mshstats.fwded_unicast++;
 627                 else
 628                         ifmsh->mshstats.fwded_mcast++;
 629                 ifmsh->mshstats.fwded_frames++;
 630         }
 631 }
 632
 633
 634 static inline struct sta_info *
 635 next_hop_deref_protected(struct mesh_path *mpath)
 636 {
 637         return rcu_dereference_protected(mpath->next_hop,
 638                                          lockdep_is_held(&mpath->state_lock));
 639 }
 640
 641
 642 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 643                                     struct ieee80211_mgmt *mgmt,
 644                                     u8 *prep_elem, u32 metric)
 645 {
 646         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 647         struct mesh_path *mpath;
 648         u8 *target_addr, *orig_addr;
 649         u8 ttl, hopcount, flags;
 650         u8 next_hop[ETH_ALEN];
 651         u32 target_sn, orig_sn, lifetime;
 652
 653         mhwmp_dbg(sdata, "received PREP from %pM\n",
 654                   PREP_IE_ORIG_ADDR(prep_elem));
 655
 656         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 657         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 658                 /* destination, no forwarding required */
 659                 return;
 660
 661         if (!ifmsh->mshcfg.dot11MeshForwarding)
 662                 return;
 663
 664         ttl = PREP_IE_TTL(prep_elem);
 665         if (ttl <= 1) {
 666                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 667                 return;
 668         }
 669
 670         rcu_read_lock();
 671         mpath = mesh_path_lookup(orig_addr, sdata);
 672         if (mpath)
 673                 spin_lock_bh(&mpath->state_lock);
 674         else
 675                 goto fail;
 676         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 677                 spin_unlock_bh(&mpath->state_lock);
 678                 goto fail;
 679         }
 680         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 681         spin_unlock_bh(&mpath->state_lock);
 682         --ttl;
 683         flags = PREP_IE_FLAGS(prep_elem);
 684         lifetime = PREP_IE_LIFETIME(prep_elem);
 685         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 686         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 687         target_sn = PREP_IE_TARGET_SN(prep_elem);
 688         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 689
 690         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 691                 cpu_to_le32(orig_sn), 0, target_addr,
 692                 cpu_to_le32(target_sn), next_hop, hopcount,
 693                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 694                 0, sdata);
 695         rcu_read_unlock();
 696
 697         sdata->u.mesh.mshstats.fwded_unicast++;
 698         sdata->u.mesh.mshstats.fwded_frames++;
 699         return;
 700
 701 fail:
 702         rcu_read_unlock();
 703         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 704 }
 705
 706 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 707                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 708 {
 709         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 710         struct mesh_path *mpath;
 711         u8 ttl;
 712         u8 *ta, *target_addr;
 713         u32 target_sn;
 714         u16 target_rcode;
 715
 716         ta = mgmt->sa;
 717         ttl = PERR_IE_TTL(perr_elem);
 718         if (ttl <= 1) {
 719                 ifmsh->mshstats.dropped_frames_ttl++;
 720                 return;
 721         }
 722         ttl--;
 723         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 724         target_sn = PERR_IE_TARGET_SN(perr_elem);
 725         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 726
 727         rcu_read_lock();
 728         mpath = mesh_path_lookup(target_addr, sdata);
 729         if (mpath) {
 730                 struct sta_info *sta;
 731
 732                 spin_lock_bh(&mpath->state_lock);
 733                 sta = next_hop_deref_protected(mpath);
 734                 if (mpath->flags & MESH_PATH_ACTIVE &&
 735                     ether_addr_equal(ta, sta->sta.addr) &&
 736                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 737                     SN_GT(target_sn, mpath->sn))) {
 738                         mpath->flags &= ~MESH_PATH_ACTIVE;
 739                         mpath->sn = target_sn;
 740                         spin_unlock_bh(&mpath->state_lock);
 741                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 742                                 goto endperr;
 743                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 744                                            cpu_to_le16(target_rcode),
 745                                            broadcast_addr, sdata);
 746                 } else
 747                         spin_unlock_bh(&mpath->state_lock);
 748         }
 749 endperr:
 750         rcu_read_unlock();
 751 }
 752
 753 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 754                                 struct ieee80211_mgmt *mgmt,
 755                                 struct ieee80211_rann_ie *rann)
 756 {
 757         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 758         struct ieee80211_local *local = sdata->local;
 759         struct sta_info *sta;
 760         struct mesh_path *mpath;
 761         u8 ttl, flags, hopcount;
 762         u8 *orig_addr;
 763         u32 orig_sn, metric, metric_txsta, interval;
 764         bool root_is_gate;
 765
 766         ttl = rann->rann_ttl;
 767         flags = rann->rann_flags;
 768         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 769         orig_addr = rann->rann_addr;
 770         orig_sn = le32_to_cpu(rann->rann_seq);
 771         interval = le32_to_cpu(rann->rann_interval);
 772         hopcount = rann->rann_hopcount;
 773         hopcount++;
 774         metric = le32_to_cpu(rann->rann_metric);
 775
 776         /*  Ignore our own RANNs */
 777         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 778                 return;
 779
 780         mhwmp_dbg(sdata,
 781                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 782                   orig_addr, mgmt->sa, root_is_gate);
 783
 784         rcu_read_lock();
 785         sta = sta_info_get(sdata, mgmt->sa);
 786         if (!sta) {
 787                 rcu_read_unlock();
 788                 return;
 789         }
 790
 791         metric_txsta = airtime_link_metric_get(local, sta);
 792
 793         mpath = mesh_path_lookup(orig_addr, sdata);
 794         if (!mpath) {
 795                 mesh_path_add(orig_addr, sdata);
 796                 mpath = mesh_path_lookup(orig_addr, sdata);
 797                 if (!mpath) {
 798                         rcu_read_unlock();
 799                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 800                         return;
 801                 }
 802         }
 803
 804         if (!(SN_LT(mpath->sn, orig_sn)) &&
 805             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 806                 rcu_read_unlock();
 807                 return;
 808         }
 809
 810         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 811              (time_after(jiffies, mpath->last_preq_to_root +
 812                                   root_path_confirmation_jiffies(sdata)) ||
 813              time_before(jiffies, mpath->last_preq_to_root))) &&
 814              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 815                 mhwmp_dbg(sdata,
 816                           "time to refresh root mpath %pM\n",
 817                           orig_addr);
 818                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 819                 mpath->last_preq_to_root = jiffies;
 820         }
 821
 822         mpath->sn = orig_sn;
 823         mpath->rann_metric = metric + metric_txsta;
 824         mpath->is_root = true;
 825         /* Recording RANNs sender address to send individually
 826          * addressed PREQs destined for root mesh STA */
 827         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 828
 829         if (root_is_gate)
 830                 mesh_path_add_gate(mpath);
 831
 832         if (ttl <= 1) {
 833                 ifmsh->mshstats.dropped_frames_ttl++;
 834                 rcu_read_unlock();
 835                 return;
 836         }
 837         ttl--;
 838
 839         if (ifmsh->mshcfg.dot11MeshForwarding) {
 840                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 841                                        cpu_to_le32(orig_sn),
 842                                        0, NULL, 0, broadcast_addr,
 843                                        hopcount, ttl, cpu_to_le32(interval),
 844                                        cpu_to_le32(metric + metric_txsta),
 845                                        0, sdata);
 846         }
 847
 848         rcu_read_unlock();
 849 }
 850
 851
 852 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 853                             struct ieee80211_mgmt *mgmt,
 854                             size_t len)
 855 {
 856         struct ieee802_11_elems elems;
 857         size_t baselen;
 858         u32 last_hop_metric;
 859         struct sta_info *sta;
 860
 861         /* need action_code */
 862         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 863                 return;
 864
 865         rcu_read_lock();
 866         sta = sta_info_get(sdata, mgmt->sa);
 867         if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 868                 rcu_read_unlock();
 869                 return;
 870         }
 871         rcu_read_unlock();
 872
 873         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 874         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 875                         len - baselen, &elems);
 876
 877         if (elems.preq) {
 878                 if (elems.preq_len != 37)
 879                         /* Right now we support just 1 destination and no AE */
 880                         return;
 881                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 882                                                       MPATH_PREQ);
 883                 if (last_hop_metric)
 884                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 885                                                 last_hop_metric);
 886         }
 887         if (elems.prep) {
 888                 if (elems.prep_len != 31)
 889                         /* Right now we support no AE */
 890                         return;
 891                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 892                                                       MPATH_PREP);
 893                 if (last_hop_metric)
 894                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 895                                                 last_hop_metric);
 896         }
 897         if (elems.perr) {
 898                 if (elems.perr_len != 15)
 899                         /* Right now we support only one destination per PERR */
 900                         return;
 901                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 902         }
 903         if (elems.rann)
 904                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 905 }
 906
 907 /**
 908  * mesh_queue_preq - queue a PREQ to a given destination
 909  *
 910  * @mpath: mesh path to discover
 911  * @flags: special attributes of the PREQ to be sent
 912  *
 913  * Locking: the function must be called from within a rcu read lock block.
 914  *
 915  */
 916 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 917 {
 918         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 919         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 920         struct mesh_preq_queue *preq_node;
 921
 922         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 923         if (!preq_node) {
 924                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 925                 return;
 926         }
 927
 928         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 929         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 930                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 931                 kfree(preq_node);
 932                 if (printk_ratelimit())
 933                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 934                 return;
 935         }
 936
 937         spin_lock(&mpath->state_lock);
 938         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 939                 spin_unlock(&mpath->state_lock);
 940                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 941                 kfree(preq_node);
 942                 return;
 943         }
 944
 945         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 946         preq_node->flags = flags;
 947
 948         mpath->flags |= MESH_PATH_REQ_QUEUED;
 949         spin_unlock(&mpath->state_lock);
 950
 951         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 952         ++ifmsh->preq_queue_len;
 953         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 954
 955         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 956                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 957
 958         else if (time_before(jiffies, ifmsh->last_preq)) {
 959                 /* avoid long wait if did not send preqs for a long time
 960                  * and jiffies wrapped around
 961                  */
 962                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 963                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 964         } else
 965                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 966                                                 min_preq_int_jiff(sdata));
 967 }
 968
 969 /**
 970  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 971  *
 972  * @sdata: local mesh subif
 973  */
 974 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 975 {
 976         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 977         struct mesh_preq_queue *preq_node;
 978         struct mesh_path *mpath;
 979         u8 ttl, target_flags;
 980         const u8 *da;
 981         u32 lifetime;
 982
 983         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 984         if (!ifmsh->preq_queue_len ||
 985                 time_before(jiffies, ifmsh->last_preq +
 986                                 min_preq_int_jiff(sdata))) {
 987                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 988                 return;
 989         }
 990
 991         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 992                         struct mesh_preq_queue, list);
 993         list_del(&preq_node->list);
 994         --ifmsh->preq_queue_len;
 995         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 996
 997         rcu_read_lock();
 998         mpath = mesh_path_lookup(preq_node->dst, sdata);
 999         if (!mpath)
1000                 goto enddiscovery;
1001
1002         spin_lock_bh(&mpath->state_lock);
1003         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1004         if (preq_node->flags & PREQ_Q_F_START) {
1005                 if (mpath->flags & MESH_PATH_RESOLVING) {
1006                         spin_unlock_bh(&mpath->state_lock);
1007                         goto enddiscovery;
1008                 } else {
1009                         mpath->flags &= ~MESH_PATH_RESOLVED;
1010                         mpath->flags |= MESH_PATH_RESOLVING;
1011                         mpath->discovery_retries = 0;
1012                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1013                 }
1014         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1015                         mpath->flags & MESH_PATH_RESOLVED) {
1016                 mpath->flags &= ~MESH_PATH_RESOLVING;
1017                 spin_unlock_bh(&mpath->state_lock);
1018                 goto enddiscovery;
1019         }
1020
1021         ifmsh->last_preq = jiffies;
1022
1023         if (time_after(jiffies, ifmsh->last_sn_update +
1024                                 net_traversal_jiffies(sdata)) ||
1025             time_before(jiffies, ifmsh->last_sn_update)) {
1026                 ++ifmsh->sn;
1027                 sdata->u.mesh.last_sn_update = jiffies;
1028         }
1029         lifetime = default_lifetime(sdata);
1030         ttl = sdata->u.mesh.mshcfg.element_ttl;
1031         if (ttl == 0) {
1032                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1033                 spin_unlock_bh(&mpath->state_lock);
1034                 goto enddiscovery;
1035         }
1036
1037         if (preq_node->flags & PREQ_Q_F_REFRESH)
1038                 target_flags = MP_F_DO;
1039         else
1040                 target_flags = MP_F_RF;
1041
1042         spin_unlock_bh(&mpath->state_lock);
1043         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1044         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1045                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1046                         cpu_to_le32(mpath->sn), da, 0,
1047                         ttl, cpu_to_le32(lifetime), 0,
1048                         cpu_to_le32(ifmsh->preq_id++), sdata);
1049         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1050
1051 enddiscovery:
1052         rcu_read_unlock();
1053         kfree(preq_node);
1054 }
1055
1056 /**
1057  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1058  *
1059  * @skb: 802.11 frame to be sent
1060  * @sdata: network subif the frame will be sent through
1061  *
1062  * Lookup next hop for given skb and start path discovery if no
1063  * forwarding information is found.
1064  *
1065  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1066  * skb is freeed here if no mpath could be allocated.
1067  */
1068 int mesh_nexthop_resolve(struct sk_buff *skb,
1069                          struct ieee80211_sub_if_data *sdata)
1070 {
1071         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1072         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1073         struct mesh_path *mpath;
1074         struct sk_buff *skb_to_free = NULL;
1075         u8 *target_addr = hdr->addr3;
1076         int err = 0;
1077
1078         rcu_read_lock();
1079         err = mesh_nexthop_lookup(skb, sdata);
1080         if (!err)
1081                 goto endlookup;
1082
1083         /* no nexthop found, start resolving */
1084         mpath = mesh_path_lookup(target_addr, sdata);
1085         if (!mpath) {
1086                 mesh_path_add(target_addr, sdata);
1087                 mpath = mesh_path_lookup(target_addr, sdata);
1088                 if (!mpath) {
1089                         mesh_path_discard_frame(skb, sdata);
1090                         err = -ENOSPC;
1091                         goto endlookup;
1092                 }
1093         }
1094
1095         if (!(mpath->flags & MESH_PATH_RESOLVING))
1096                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1097
1098         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1099                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1100
1101         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1102         ieee80211_set_qos_hdr(sdata, skb);
1103         skb_queue_tail(&mpath->frame_queue, skb);
1104         err = -ENOENT;
1105         if (skb_to_free)
1106                 mesh_path_discard_frame(skb_to_free, sdata);
1107
1108 endlookup:
1109         rcu_read_unlock();
1110         return err;
1111 }
1112 /**
1113  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1114  * this function is considered "using" the associated mpath, so preempt a path
1115  * refresh if this mpath expires soon.
1116  *
1117  * @skb: 802.11 frame to be sent
1118  * @sdata: network subif the frame will be sent through
1119  *
1120  * Returns: 0 if the next hop was found. Nonzero otherwise.
1121  */
1122 int mesh_nexthop_lookup(struct sk_buff *skb,
1123                         struct ieee80211_sub_if_data *sdata)
1124 {
1125         struct mesh_path *mpath;
1126         struct sta_info *next_hop;
1127         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1128         u8 *target_addr = hdr->addr3;
1129         int err = -ENOENT;
1130
1131         rcu_read_lock();
1132         mpath = mesh_path_lookup(target_addr, sdata);
1133
1134         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1135                 goto endlookup;
1136
1137         if (time_after(jiffies,
1138                        mpath->exp_time -
1139                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1140             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1141             !(mpath->flags & MESH_PATH_RESOLVING) &&
1142             !(mpath->flags & MESH_PATH_FIXED))
1143                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1144
1145         next_hop = rcu_dereference(mpath->next_hop);
1146         if (next_hop) {
1147                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1148                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1149                 err = 0;
1150         }
1151
1152 endlookup:
1153         rcu_read_unlock();
1154         return err;
1155 }
1156
1157 void mesh_path_timer(unsigned long data)
1158 {
1159         struct mesh_path *mpath = (void *) data;
1160         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1161         int ret;
1162
1163         if (sdata->local->quiescing)
1164                 return;
1165
1166         spin_lock_bh(&mpath->state_lock);
1167         if (mpath->flags & MESH_PATH_RESOLVED ||
1168                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1169                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1170                 spin_unlock_bh(&mpath->state_lock);
1171         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1172                 ++mpath->discovery_retries;
1173                 mpath->discovery_timeout *= 2;
1174                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1175                 spin_unlock_bh(&mpath->state_lock);
1176                 mesh_queue_preq(mpath, 0);
1177         } else {
1178                 mpath->flags = 0;
1179                 mpath->exp_time = jiffies;
1180                 spin_unlock_bh(&mpath->state_lock);
1181                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1182                         ret = mesh_path_send_to_gates(mpath);
1183                         if (ret)
1184                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1185                 } else
1186                         mesh_path_flush_pending(mpath);
1187         }
1188 }
1189
1190 void
1191 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1192 {
1193         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1194         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1195         u8 flags, target_flags = 0;
1196
1197         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1198                         ? RANN_FLAG_IS_GATE : 0;
1199
1200         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1201         case IEEE80211_PROACTIVE_RANN:
1202                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1203                                cpu_to_le32(++ifmsh->sn),
1204                                0, NULL, 0, broadcast_addr,
1205                                0, ifmsh->mshcfg.element_ttl,
1206                                cpu_to_le32(interval), 0, 0, sdata);
1207                 break;
1208         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1209                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1210         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1211                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1212                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1213                                 IEEE80211_PREQ_USN_FLAG;
1214                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1215                                 cpu_to_le32(++ifmsh->sn), target_flags,
1216                                 (u8 *) broadcast_addr, 0, broadcast_addr,
1217                                 0, ifmsh->mshcfg.element_ttl,
1218                                 cpu_to_le32(interval),
1219                                 0, cpu_to_le32(ifmsh->preq_id++), sdata);
1220                 break;
1221         default:
1222                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1223                 return;
1224         }
1225 }