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                             IEEE80211_ENCRYPT_HEADROOM +
 251                             IEEE80211_ENCRYPT_TAILROOM +
 252                             hdr_len +
 253                             2 + 15 /* PERR IE */);
 254         if (!skb)
 255                 return -1;
 256         skb_reserve(skb, local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM);
 257         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 258         memset(mgmt, 0, hdr_len);
 259         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 260                                           IEEE80211_STYPE_ACTION);
 261
 262         memcpy(mgmt->da, ra, ETH_ALEN);
 263         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 264         /* BSSID == SA */
 265         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 266         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 267         mgmt->u.action.u.mesh_action.action_code =
 268                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 269         ie_len = 15;
 270         pos = skb_put(skb, 2 + ie_len);
 271         *pos++ = WLAN_EID_PERR;
 272         *pos++ = ie_len;
 273         /* ttl */
 274         *pos++ = ttl;
 275         /* number of destinations */
 276         *pos++ = 1;
 277         /*
 278          * flags bit, bit 1 is unset if we know the sequence number and
 279          * bit 2 is set if we have a reason code
 280          */
 281         *pos = 0;
 282         if (!target_sn)
 283                 *pos |= MP_F_USN;
 284         if (target_rcode)
 285                 *pos |= MP_F_RCODE;
 286         pos++;
 287         memcpy(pos, target, ETH_ALEN);
 288         pos += ETH_ALEN;
 289         memcpy(pos, &target_sn, 4);
 290         pos += 4;
 291         memcpy(pos, &target_rcode, 2);
 292
 293         /* see note in function header */
 294         prepare_frame_for_deferred_tx(sdata, skb);
 295         ifmsh->next_perr = TU_TO_EXP_TIME(
 296                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 297         ieee80211_add_pending_skb(local, skb);
 298         return 0;
 299 }
 300
 301 void ieee80211s_update_metric(struct ieee80211_local *local,
 302                 struct sta_info *sta, struct sk_buff *skb)
 303 {
 304         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 305         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 306         int failed;
 307
 308         if (!ieee80211_is_data(hdr->frame_control))
 309                 return;
 310
 311         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 312
 313         /* moving average, scaled to 100 */
 314         sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
 315         if (sta->fail_avg > 95)
 316                 mesh_plink_broken(sta);
 317 }
 318
 319 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 320                                    struct sta_info *sta)
 321 {
 322         struct rate_info rinfo;
 323         /* This should be adjusted for each device */
 324         int device_constant = 1 << ARITH_SHIFT;
 325         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 326         int s_unit = 1 << ARITH_SHIFT;
 327         int rate, err;
 328         u32 tx_time, estimated_retx;
 329         u64 result;
 330
 331         if (sta->fail_avg >= 100)
 332                 return MAX_METRIC;
 333
 334         sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
 335         rate = cfg80211_calculate_bitrate(&rinfo);
 336         if (WARN_ON(!rate))
 337                 return MAX_METRIC;
 338
 339         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 340
 341         /* bitrate is in units of 100 Kbps, while we need rate in units of
 342          * 1Mbps. This will be corrected on tx_time computation.
 343          */
 344         tx_time = (device_constant + 10 * test_frame_len / rate);
 345         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 346         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 347         return (u32)result;
 348 }
 349
 350 /**
 351  * hwmp_route_info_get - Update routing info to originator and transmitter
 352  *
 353  * @sdata: local mesh subif
 354  * @mgmt: mesh management frame
 355  * @hwmp_ie: hwmp information element (PREP or PREQ)
 356  *
 357  * This function updates the path routing information to the originator and the
 358  * transmitter of a HWMP PREQ or PREP frame.
 359  *
 360  * Returns: metric to frame originator or 0 if the frame should not be further
 361  * processed
 362  *
 363  * Notes: this function is the only place (besides user-provided info) where
 364  * path routing information is updated.
 365  */
 366 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 367                             struct ieee80211_mgmt *mgmt,
 368                             u8 *hwmp_ie, enum mpath_frame_type action)
 369 {
 370         struct ieee80211_local *local = sdata->local;
 371         struct mesh_path *mpath;
 372         struct sta_info *sta;
 373         bool fresh_info;
 374         u8 *orig_addr, *ta;
 375         u32 orig_sn, orig_metric;
 376         unsigned long orig_lifetime, exp_time;
 377         u32 last_hop_metric, new_metric;
 378         bool process = true;
 379
 380         rcu_read_lock();
 381         sta = sta_info_get(sdata, mgmt->sa);
 382         if (!sta) {
 383                 rcu_read_unlock();
 384                 return 0;
 385         }
 386
 387         last_hop_metric = airtime_link_metric_get(local, sta);
 388         /* Update and check originator routing info */
 389         fresh_info = true;
 390
 391         switch (action) {
 392         case MPATH_PREQ:
 393                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 394                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 395                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 396                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 397                 break;
 398         case MPATH_PREP:
 399                 /* Originator here refers to the MP that was the target in the
 400                  * Path Request. We divert from the nomenclature in the draft
 401                  * so that we can easily use a single function to gather path
 402                  * information from both PREQ and PREP frames.
 403                  */
 404                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 405                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 406                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 407                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 408                 break;
 409         default:
 410                 rcu_read_unlock();
 411                 return 0;
 412         }
 413         new_metric = orig_metric + last_hop_metric;
 414         if (new_metric < orig_metric)
 415                 new_metric = MAX_METRIC;
 416         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 417
 418         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 419                 /* This MP is the originator, we are not interested in this
 420                  * frame, except for updating transmitter's path info.
 421                  */
 422                 process = false;
 423                 fresh_info = false;
 424         } else {
 425                 mpath = mesh_path_lookup(orig_addr, sdata);
 426                 if (mpath) {
 427                         spin_lock_bh(&mpath->state_lock);
 428                         if (mpath->flags & MESH_PATH_FIXED)
 429                                 fresh_info = false;
 430                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 431                             (mpath->flags & MESH_PATH_SN_VALID)) {
 432                                 if (SN_GT(mpath->sn, orig_sn) ||
 433                                     (mpath->sn == orig_sn &&
 434                                      new_metric >= mpath->metric)) {
 435                                         process = false;
 436                                         fresh_info = false;
 437                                 }
 438                         }
 439                 } else {
 440                         mesh_path_add(orig_addr, sdata);
 441                         mpath = mesh_path_lookup(orig_addr, sdata);
 442                         if (!mpath) {
 443                                 rcu_read_unlock();
 444                                 return 0;
 445                         }
 446                         spin_lock_bh(&mpath->state_lock);
 447                 }
 448
 449                 if (fresh_info) {
 450                         mesh_path_assign_nexthop(mpath, sta);
 451                         mpath->flags |= MESH_PATH_SN_VALID;
 452                         mpath->metric = new_metric;
 453                         mpath->sn = orig_sn;
 454                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 455                                           ?  mpath->exp_time : exp_time;
 456                         mesh_path_activate(mpath);
 457                         spin_unlock_bh(&mpath->state_lock);
 458                         mesh_path_tx_pending(mpath);
 459                         /* draft says preq_id should be saved to, but there does
 460                          * not seem to be any use for it, skipping by now
 461                          */
 462                 } else
 463                         spin_unlock_bh(&mpath->state_lock);
 464         }
 465
 466         /* Update and check transmitter routing info */
 467         ta = mgmt->sa;
 468         if (ether_addr_equal(orig_addr, ta))
 469                 fresh_info = false;
 470         else {
 471                 fresh_info = true;
 472
 473                 mpath = mesh_path_lookup(ta, sdata);
 474                 if (mpath) {
 475                         spin_lock_bh(&mpath->state_lock);
 476                         if ((mpath->flags & MESH_PATH_FIXED) ||
 477                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 478                                         (last_hop_metric > mpath->metric)))
 479                                 fresh_info = false;
 480                 } else {
 481                         mesh_path_add(ta, sdata);
 482                         mpath = mesh_path_lookup(ta, sdata);
 483                         if (!mpath) {
 484                                 rcu_read_unlock();
 485                                 return 0;
 486                         }
 487                         spin_lock_bh(&mpath->state_lock);
 488                 }
 489
 490                 if (fresh_info) {
 491                         mesh_path_assign_nexthop(mpath, sta);
 492                         mpath->metric = last_hop_metric;
 493                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 494                                           ?  mpath->exp_time : exp_time;
 495                         mesh_path_activate(mpath);
 496                         spin_unlock_bh(&mpath->state_lock);
 497                         mesh_path_tx_pending(mpath);
 498                 } else
 499                         spin_unlock_bh(&mpath->state_lock);
 500         }
 501
 502         rcu_read_unlock();
 503
 504         return process ? new_metric : 0;
 505 }
 506
 507 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 508                                     struct ieee80211_mgmt *mgmt,
 509                                     u8 *preq_elem, u32 metric)
 510 {
 511         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 512         struct mesh_path *mpath = NULL;
 513         u8 *target_addr, *orig_addr;
 514         const u8 *da;
 515         u8 target_flags, ttl, flags;
 516         u32 orig_sn, target_sn, lifetime, orig_metric;
 517         bool reply = false;
 518         bool forward = true;
 519         bool root_is_gate;
 520
 521         /* Update target SN, if present */
 522         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 523         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 524         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 525         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 526         target_flags = PREQ_IE_TARGET_F(preq_elem);
 527         orig_metric = metric;
 528         /* Proactive PREQ gate announcements */
 529         flags = PREQ_IE_FLAGS(preq_elem);
 530         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 531
 532         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 533
 534         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 535                 mhwmp_dbg(sdata, "PREQ is for us\n");
 536                 forward = false;
 537                 reply = true;
 538                 metric = 0;
 539                 if (time_after(jiffies, ifmsh->last_sn_update +
 540                                         net_traversal_jiffies(sdata)) ||
 541                     time_before(jiffies, ifmsh->last_sn_update)) {
 542                         target_sn = ++ifmsh->sn;
 543                         ifmsh->last_sn_update = jiffies;
 544                 }
 545         } else if (is_broadcast_ether_addr(target_addr) &&
 546                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 547                 rcu_read_lock();
 548                 mpath = mesh_path_lookup(orig_addr, sdata);
 549                 if (mpath) {
 550                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 551                                 reply = true;
 552                                 target_addr = sdata->vif.addr;
 553                                 target_sn = ++ifmsh->sn;
 554                                 metric = 0;
 555                                 ifmsh->last_sn_update = jiffies;
 556                         }
 557                         if (root_is_gate)
 558                                 mesh_path_add_gate(mpath);
 559                 }
 560                 rcu_read_unlock();
 561         } else {
 562                 rcu_read_lock();
 563                 mpath = mesh_path_lookup(target_addr, sdata);
 564                 if (mpath) {
 565                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 566                                         SN_LT(mpath->sn, target_sn)) {
 567                                 mpath->sn = target_sn;
 568                                 mpath->flags |= MESH_PATH_SN_VALID;
 569                         } else if ((!(target_flags & MP_F_DO)) &&
 570                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 571                                 reply = true;
 572                                 metric = mpath->metric;
 573                                 target_sn = mpath->sn;
 574                                 if (target_flags & MP_F_RF)
 575                                         target_flags |= MP_F_DO;
 576                                 else
 577                                         forward = false;
 578                         }
 579                 }
 580                 rcu_read_unlock();
 581         }
 582
 583         if (reply) {
 584                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 585                 ttl = ifmsh->mshcfg.element_ttl;
 586                 if (ttl != 0) {
 587                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 588                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 589                                 cpu_to_le32(orig_sn), 0, target_addr,
 590                                 cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 591                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 592                                 0, sdata);
 593                 } else {
 594                         ifmsh->mshstats.dropped_frames_ttl++;
 595                 }
 596         }
 597
 598         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 599                 u32 preq_id;
 600                 u8 hopcount;
 601
 602                 ttl = PREQ_IE_TTL(preq_elem);
 603                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 604                 if (ttl <= 1) {
 605                         ifmsh->mshstats.dropped_frames_ttl++;
 606                         return;
 607                 }
 608                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 609                 --ttl;
 610                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 611                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 612                 da = (mpath && mpath->is_root) ?
 613                         mpath->rann_snd_addr : broadcast_addr;
 614
 615                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 616                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 617                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 618                         metric = orig_metric;
 619                 }
 620
 621                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 622                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 623                                 cpu_to_le32(target_sn), da,
 624                                 hopcount, ttl, cpu_to_le32(lifetime),
 625                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 626                                 sdata);
 627                 if (!is_multicast_ether_addr(da))
 628                         ifmsh->mshstats.fwded_unicast++;
 629                 else
 630                         ifmsh->mshstats.fwded_mcast++;
 631                 ifmsh->mshstats.fwded_frames++;
 632         }
 633 }
 634
 635
 636 static inline struct sta_info *
 637 next_hop_deref_protected(struct mesh_path *mpath)
 638 {
 639         return rcu_dereference_protected(mpath->next_hop,
 640                                          lockdep_is_held(&mpath->state_lock));
 641 }
 642
 643
 644 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 645                                     struct ieee80211_mgmt *mgmt,
 646                                     u8 *prep_elem, u32 metric)
 647 {
 648         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 649         struct mesh_path *mpath;
 650         u8 *target_addr, *orig_addr;
 651         u8 ttl, hopcount, flags;
 652         u8 next_hop[ETH_ALEN];
 653         u32 target_sn, orig_sn, lifetime;
 654
 655         mhwmp_dbg(sdata, "received PREP from %pM\n",
 656                   PREP_IE_ORIG_ADDR(prep_elem));
 657
 658         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 659         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 660                 /* destination, no forwarding required */
 661                 return;
 662
 663         if (!ifmsh->mshcfg.dot11MeshForwarding)
 664                 return;
 665
 666         ttl = PREP_IE_TTL(prep_elem);
 667         if (ttl <= 1) {
 668                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 669                 return;
 670         }
 671
 672         rcu_read_lock();
 673         mpath = mesh_path_lookup(orig_addr, sdata);
 674         if (mpath)
 675                 spin_lock_bh(&mpath->state_lock);
 676         else
 677                 goto fail;
 678         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 679                 spin_unlock_bh(&mpath->state_lock);
 680                 goto fail;
 681         }
 682         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 683         spin_unlock_bh(&mpath->state_lock);
 684         --ttl;
 685         flags = PREP_IE_FLAGS(prep_elem);
 686         lifetime = PREP_IE_LIFETIME(prep_elem);
 687         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 688         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 689         target_sn = PREP_IE_TARGET_SN(prep_elem);
 690         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 691
 692         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 693                 cpu_to_le32(orig_sn), 0, target_addr,
 694                 cpu_to_le32(target_sn), next_hop, hopcount,
 695                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 696                 0, sdata);
 697         rcu_read_unlock();
 698
 699         sdata->u.mesh.mshstats.fwded_unicast++;
 700         sdata->u.mesh.mshstats.fwded_frames++;
 701         return;
 702
 703 fail:
 704         rcu_read_unlock();
 705         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 706 }
 707
 708 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 709                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 710 {
 711         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 712         struct mesh_path *mpath;
 713         u8 ttl;
 714         u8 *ta, *target_addr;
 715         u32 target_sn;
 716         u16 target_rcode;
 717
 718         ta = mgmt->sa;
 719         ttl = PERR_IE_TTL(perr_elem);
 720         if (ttl <= 1) {
 721                 ifmsh->mshstats.dropped_frames_ttl++;
 722                 return;
 723         }
 724         ttl--;
 725         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 726         target_sn = PERR_IE_TARGET_SN(perr_elem);
 727         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 728
 729         rcu_read_lock();
 730         mpath = mesh_path_lookup(target_addr, sdata);
 731         if (mpath) {
 732                 struct sta_info *sta;
 733
 734                 spin_lock_bh(&mpath->state_lock);
 735                 sta = next_hop_deref_protected(mpath);
 736                 if (mpath->flags & MESH_PATH_ACTIVE &&
 737                     ether_addr_equal(ta, sta->sta.addr) &&
 738                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 739                     SN_GT(target_sn, mpath->sn))) {
 740                         mpath->flags &= ~MESH_PATH_ACTIVE;
 741                         mpath->sn = target_sn;
 742                         spin_unlock_bh(&mpath->state_lock);
 743                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 744                                 goto endperr;
 745                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 746                                            cpu_to_le16(target_rcode),
 747                                            broadcast_addr, sdata);
 748                 } else
 749                         spin_unlock_bh(&mpath->state_lock);
 750         }
 751 endperr:
 752         rcu_read_unlock();
 753 }
 754
 755 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 756                                 struct ieee80211_mgmt *mgmt,
 757                                 struct ieee80211_rann_ie *rann)
 758 {
 759         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 760         struct ieee80211_local *local = sdata->local;
 761         struct sta_info *sta;
 762         struct mesh_path *mpath;
 763         u8 ttl, flags, hopcount;
 764         u8 *orig_addr;
 765         u32 orig_sn, metric, metric_txsta, interval;
 766         bool root_is_gate;
 767
 768         ttl = rann->rann_ttl;
 769         flags = rann->rann_flags;
 770         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 771         orig_addr = rann->rann_addr;
 772         orig_sn = le32_to_cpu(rann->rann_seq);
 773         interval = le32_to_cpu(rann->rann_interval);
 774         hopcount = rann->rann_hopcount;
 775         hopcount++;
 776         metric = le32_to_cpu(rann->rann_metric);
 777
 778         /*  Ignore our own RANNs */
 779         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 780                 return;
 781
 782         mhwmp_dbg(sdata,
 783                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 784                   orig_addr, mgmt->sa, root_is_gate);
 785
 786         rcu_read_lock();
 787         sta = sta_info_get(sdata, mgmt->sa);
 788         if (!sta) {
 789                 rcu_read_unlock();
 790                 return;
 791         }
 792
 793         metric_txsta = airtime_link_metric_get(local, sta);
 794
 795         mpath = mesh_path_lookup(orig_addr, sdata);
 796         if (!mpath) {
 797                 mesh_path_add(orig_addr, sdata);
 798                 mpath = mesh_path_lookup(orig_addr, sdata);
 799                 if (!mpath) {
 800                         rcu_read_unlock();
 801                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 802                         return;
 803                 }
 804         }
 805
 806         if (!(SN_LT(mpath->sn, orig_sn)) &&
 807             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 808                 rcu_read_unlock();
 809                 return;
 810         }
 811
 812         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 813              (time_after(jiffies, mpath->last_preq_to_root +
 814                                   root_path_confirmation_jiffies(sdata)) ||
 815              time_before(jiffies, mpath->last_preq_to_root))) &&
 816              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 817                 mhwmp_dbg(sdata,
 818                           "time to refresh root mpath %pM\n",
 819                           orig_addr);
 820                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 821                 mpath->last_preq_to_root = jiffies;
 822         }
 823
 824         mpath->sn = orig_sn;
 825         mpath->rann_metric = metric + metric_txsta;
 826         mpath->is_root = true;
 827         /* Recording RANNs sender address to send individually
 828          * addressed PREQs destined for root mesh STA */
 829         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 830
 831         if (root_is_gate)
 832                 mesh_path_add_gate(mpath);
 833
 834         if (ttl <= 1) {
 835                 ifmsh->mshstats.dropped_frames_ttl++;
 836                 rcu_read_unlock();
 837                 return;
 838         }
 839         ttl--;
 840
 841         if (ifmsh->mshcfg.dot11MeshForwarding) {
 842                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 843                                        cpu_to_le32(orig_sn),
 844                                        0, NULL, 0, broadcast_addr,
 845                                        hopcount, ttl, cpu_to_le32(interval),
 846                                        cpu_to_le32(metric + metric_txsta),
 847                                        0, sdata);
 848         }
 849
 850         rcu_read_unlock();
 851 }
 852
 853
 854 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 855                             struct ieee80211_mgmt *mgmt,
 856                             size_t len)
 857 {
 858         struct ieee802_11_elems elems;
 859         size_t baselen;
 860         u32 last_hop_metric;
 861         struct sta_info *sta;
 862
 863         /* need action_code */
 864         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 865                 return;
 866
 867         rcu_read_lock();
 868         sta = sta_info_get(sdata, mgmt->sa);
 869         if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 870                 rcu_read_unlock();
 871                 return;
 872         }
 873         rcu_read_unlock();
 874
 875         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 876         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 877                         len - baselen, &elems);
 878
 879         if (elems.preq) {
 880                 if (elems.preq_len != 37)
 881                         /* Right now we support just 1 destination and no AE */
 882                         return;
 883                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 884                                                       MPATH_PREQ);
 885                 if (last_hop_metric)
 886                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 887                                                 last_hop_metric);
 888         }
 889         if (elems.prep) {
 890                 if (elems.prep_len != 31)
 891                         /* Right now we support no AE */
 892                         return;
 893                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 894                                                       MPATH_PREP);
 895                 if (last_hop_metric)
 896                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 897                                                 last_hop_metric);
 898         }
 899         if (elems.perr) {
 900                 if (elems.perr_len != 15)
 901                         /* Right now we support only one destination per PERR */
 902                         return;
 903                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 904         }
 905         if (elems.rann)
 906                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 907 }
 908
 909 /**
 910  * mesh_queue_preq - queue a PREQ to a given destination
 911  *
 912  * @mpath: mesh path to discover
 913  * @flags: special attributes of the PREQ to be sent
 914  *
 915  * Locking: the function must be called from within a rcu read lock block.
 916  *
 917  */
 918 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 919 {
 920         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 921         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 922         struct mesh_preq_queue *preq_node;
 923
 924         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 925         if (!preq_node) {
 926                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 927                 return;
 928         }
 929
 930         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 931         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 932                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 933                 kfree(preq_node);
 934                 if (printk_ratelimit())
 935                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 936                 return;
 937         }
 938
 939         spin_lock(&mpath->state_lock);
 940         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 941                 spin_unlock(&mpath->state_lock);
 942                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 943                 kfree(preq_node);
 944                 return;
 945         }
 946
 947         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 948         preq_node->flags = flags;
 949
 950         mpath->flags |= MESH_PATH_REQ_QUEUED;
 951         spin_unlock(&mpath->state_lock);
 952
 953         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 954         ++ifmsh->preq_queue_len;
 955         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 956
 957         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 958                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 959
 960         else if (time_before(jiffies, ifmsh->last_preq)) {
 961                 /* avoid long wait if did not send preqs for a long time
 962                  * and jiffies wrapped around
 963                  */
 964                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 965                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 966         } else
 967                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 968                                                 min_preq_int_jiff(sdata));
 969 }
 970
 971 /**
 972  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 973  *
 974  * @sdata: local mesh subif
 975  */
 976 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 977 {
 978         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 979         struct mesh_preq_queue *preq_node;
 980         struct mesh_path *mpath;
 981         u8 ttl, target_flags;
 982         const u8 *da;
 983         u32 lifetime;
 984
 985         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 986         if (!ifmsh->preq_queue_len ||
 987                 time_before(jiffies, ifmsh->last_preq +
 988                                 min_preq_int_jiff(sdata))) {
 989                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 990                 return;
 991         }
 992
 993         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 994                         struct mesh_preq_queue, list);
 995         list_del(&preq_node->list);
 996         --ifmsh->preq_queue_len;
 997         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 998
 999         rcu_read_lock();
1000         mpath = mesh_path_lookup(preq_node->dst, sdata);
1001         if (!mpath)
1002                 goto enddiscovery;
1003
1004         spin_lock_bh(&mpath->state_lock);
1005         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1006         if (preq_node->flags & PREQ_Q_F_START) {
1007                 if (mpath->flags & MESH_PATH_RESOLVING) {
1008                         spin_unlock_bh(&mpath->state_lock);
1009                         goto enddiscovery;
1010                 } else {
1011                         mpath->flags &= ~MESH_PATH_RESOLVED;
1012                         mpath->flags |= MESH_PATH_RESOLVING;
1013                         mpath->discovery_retries = 0;
1014                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1015                 }
1016         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1017                         mpath->flags & MESH_PATH_RESOLVED) {
1018                 mpath->flags &= ~MESH_PATH_RESOLVING;
1019                 spin_unlock_bh(&mpath->state_lock);
1020                 goto enddiscovery;
1021         }
1022
1023         ifmsh->last_preq = jiffies;
1024
1025         if (time_after(jiffies, ifmsh->last_sn_update +
1026                                 net_traversal_jiffies(sdata)) ||
1027             time_before(jiffies, ifmsh->last_sn_update)) {
1028                 ++ifmsh->sn;
1029                 sdata->u.mesh.last_sn_update = jiffies;
1030         }
1031         lifetime = default_lifetime(sdata);
1032         ttl = sdata->u.mesh.mshcfg.element_ttl;
1033         if (ttl == 0) {
1034                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1035                 spin_unlock_bh(&mpath->state_lock);
1036                 goto enddiscovery;
1037         }
1038
1039         if (preq_node->flags & PREQ_Q_F_REFRESH)
1040                 target_flags = MP_F_DO;
1041         else
1042                 target_flags = MP_F_RF;
1043
1044         spin_unlock_bh(&mpath->state_lock);
1045         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1046         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1047                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1048                         cpu_to_le32(mpath->sn), da, 0,
1049                         ttl, cpu_to_le32(lifetime), 0,
1050                         cpu_to_le32(ifmsh->preq_id++), sdata);
1051         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1052
1053 enddiscovery:
1054         rcu_read_unlock();
1055         kfree(preq_node);
1056 }
1057
1058 /**
1059  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1060  *
1061  * @skb: 802.11 frame to be sent
1062  * @sdata: network subif the frame will be sent through
1063  *
1064  * Lookup next hop for given skb and start path discovery if no
1065  * forwarding information is found.
1066  *
1067  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1068  * skb is freeed here if no mpath could be allocated.
1069  */
1070 int mesh_nexthop_resolve(struct sk_buff *skb,
1071                          struct ieee80211_sub_if_data *sdata)
1072 {
1073         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1074         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1075         struct mesh_path *mpath;
1076         struct sk_buff *skb_to_free = NULL;
1077         u8 *target_addr = hdr->addr3;
1078         int err = 0;
1079
1080         rcu_read_lock();
1081         err = mesh_nexthop_lookup(skb, sdata);
1082         if (!err)
1083                 goto endlookup;
1084
1085         /* no nexthop found, start resolving */
1086         mpath = mesh_path_lookup(target_addr, sdata);
1087         if (!mpath) {
1088                 mesh_path_add(target_addr, sdata);
1089                 mpath = mesh_path_lookup(target_addr, sdata);
1090                 if (!mpath) {
1091                         mesh_path_discard_frame(skb, sdata);
1092                         err = -ENOSPC;
1093                         goto endlookup;
1094                 }
1095         }
1096
1097         if (!(mpath->flags & MESH_PATH_RESOLVING))
1098                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1099
1100         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1101                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1102
1103         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1104         ieee80211_set_qos_hdr(sdata, skb);
1105         skb_queue_tail(&mpath->frame_queue, skb);
1106         err = -ENOENT;
1107         if (skb_to_free)
1108                 mesh_path_discard_frame(skb_to_free, sdata);
1109
1110 endlookup:
1111         rcu_read_unlock();
1112         return err;
1113 }
1114 /**
1115  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1116  * this function is considered "using" the associated mpath, so preempt a path
1117  * refresh if this mpath expires soon.
1118  *
1119  * @skb: 802.11 frame to be sent
1120  * @sdata: network subif the frame will be sent through
1121  *
1122  * Returns: 0 if the next hop was found. Nonzero otherwise.
1123  */
1124 int mesh_nexthop_lookup(struct sk_buff *skb,
1125                         struct ieee80211_sub_if_data *sdata)
1126 {
1127         struct mesh_path *mpath;
1128         struct sta_info *next_hop;
1129         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1130         u8 *target_addr = hdr->addr3;
1131         int err = -ENOENT;
1132
1133         rcu_read_lock();
1134         mpath = mesh_path_lookup(target_addr, sdata);
1135
1136         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1137                 goto endlookup;
1138
1139         if (time_after(jiffies,
1140                        mpath->exp_time -
1141                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1142             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1143             !(mpath->flags & MESH_PATH_RESOLVING) &&
1144             !(mpath->flags & MESH_PATH_FIXED))
1145                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1146
1147         next_hop = rcu_dereference(mpath->next_hop);
1148         if (next_hop) {
1149                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1150                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1151                 err = 0;
1152         }
1153
1154 endlookup:
1155         rcu_read_unlock();
1156         return err;
1157 }
1158
1159 void mesh_path_timer(unsigned long data)
1160 {
1161         struct mesh_path *mpath = (void *) data;
1162         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1163         int ret;
1164
1165         if (sdata->local->quiescing)
1166                 return;
1167
1168         spin_lock_bh(&mpath->state_lock);
1169         if (mpath->flags & MESH_PATH_RESOLVED ||
1170                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1171                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1172                 spin_unlock_bh(&mpath->state_lock);
1173         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1174                 ++mpath->discovery_retries;
1175                 mpath->discovery_timeout *= 2;
1176                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1177                 spin_unlock_bh(&mpath->state_lock);
1178                 mesh_queue_preq(mpath, 0);
1179         } else {
1180                 mpath->flags = 0;
1181                 mpath->exp_time = jiffies;
1182                 spin_unlock_bh(&mpath->state_lock);
1183                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1184                         ret = mesh_path_send_to_gates(mpath);
1185                         if (ret)
1186                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1187                 } else
1188                         mesh_path_flush_pending(mpath);
1189         }
1190 }
1191
1192 void
1193 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1194 {
1195         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1196         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1197         u8 flags, target_flags = 0;
1198
1199         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1200                         ? RANN_FLAG_IS_GATE : 0;
1201
1202         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1203         case IEEE80211_PROACTIVE_RANN:
1204                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1205                                cpu_to_le32(++ifmsh->sn),
1206                                0, NULL, 0, broadcast_addr,
1207                                0, ifmsh->mshcfg.element_ttl,
1208                                cpu_to_le32(interval), 0, 0, sdata);
1209                 break;
1210         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1211                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1212         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1213                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1214                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1215                                 IEEE80211_PREQ_USN_FLAG;
1216                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1217                                 cpu_to_le32(++ifmsh->sn), target_flags,
1218                                 (u8 *) broadcast_addr, 0, broadcast_addr,
1219                                 0, ifmsh->mshcfg.element_ttl,
1220                                 cpu_to_le32(interval),
1221                                 0, cpu_to_le32(ifmsh->preq_id++), sdata);
1222                 break;
1223         default:
1224                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1225                 return;
1226         }
1227 }