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 static void mesh_queue_preq(struct mesh_path *, u8);
  23
  24 static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
  25 {
  26         if (ae)
  27                 offset += 6;
  28         return get_unaligned_le32(preq_elem + offset);
  29 }
  30
  31 static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
  32 {
  33         if (ae)
  34                 offset += 6;
  35         return get_unaligned_le16(preq_elem + offset);
  36 }
  37
  38 /* HWMP IE processing macros */
  39 #define AE_F                    (1<<6)
  40 #define AE_F_SET(x)             (*x & AE_F)
  41 #define PREQ_IE_FLAGS(x)        (*(x))
  42 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  43 #define PREQ_IE_TTL(x)          (*(x + 2))
  44 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  45 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  46 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  47 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  48 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  49 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  50 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  51 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  52
  53
  54 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  55 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  56 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  57 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  58 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  59 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  60 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  61 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  62 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  63
  64 #define PERR_IE_TTL(x)          (*(x))
  65 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  66 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  67 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  68 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  69
  70 #define MSEC_TO_TU(x) (x*1000/1024)
  71 #define SN_GT(x, y) ((s32)(y - x) < 0)
  72 #define SN_LT(x, y) ((s32)(x - y) < 0)
  73 #define MAX_SANE_SN_DELTA 32
  74
  75 static inline u32 SN_DELTA(u32 x, u32 y)
  76 {
  77         return x >= y ? x - y : y - x;
  78 }
  79
  80 #define net_traversal_jiffies(s) \
  81         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  82 #define default_lifetime(s) \
  83         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  84 #define min_preq_int_jiff(s) \
  85         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  86 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  87 #define disc_timeout_jiff(s) \
  88         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  89 #define root_path_confirmation_jiffies(s) \
  90         msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  91
  92 enum mpath_frame_type {
  93         MPATH_PREQ = 0,
  94         MPATH_PREP,
  95         MPATH_PERR,
  96         MPATH_RANN
  97 };
  98
  99 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 100
 101 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 102                                   const u8 *orig_addr, u32 orig_sn,
 103                                   u8 target_flags, const u8 *target,
 104                                   u32 target_sn, const u8 *da,
 105                                   u8 hop_count, u8 ttl,
 106                                   u32 lifetime, u32 metric, u32 preq_id,
 107                                   struct ieee80211_sub_if_data *sdata)
 108 {
 109         struct ieee80211_local *local = sdata->local;
 110         struct sk_buff *skb;
 111         struct ieee80211_mgmt *mgmt;
 112         u8 *pos, ie_len;
 113         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 114                       sizeof(mgmt->u.action.u.mesh_action);
 115
 116         skb = dev_alloc_skb(local->tx_headroom +
 117                             hdr_len +
 118                             2 + 37); /* max HWMP IE */
 119         if (!skb)
 120                 return -1;
 121         skb_reserve(skb, local->tx_headroom);
 122         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 123         memset(mgmt, 0, hdr_len);
 124         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 125                                           IEEE80211_STYPE_ACTION);
 126
 127         memcpy(mgmt->da, da, ETH_ALEN);
 128         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 129         /* BSSID == SA */
 130         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 131         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 132         mgmt->u.action.u.mesh_action.action_code =
 133                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 134
 135         switch (action) {
 136         case MPATH_PREQ:
 137                 mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 138                 ie_len = 37;
 139                 pos = skb_put(skb, 2 + ie_len);
 140                 *pos++ = WLAN_EID_PREQ;
 141                 break;
 142         case MPATH_PREP:
 143                 mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
 144                 ie_len = 31;
 145                 pos = skb_put(skb, 2 + ie_len);
 146                 *pos++ = WLAN_EID_PREP;
 147                 break;
 148         case MPATH_RANN:
 149                 mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 150                 ie_len = sizeof(struct ieee80211_rann_ie);
 151                 pos = skb_put(skb, 2 + ie_len);
 152                 *pos++ = WLAN_EID_RANN;
 153                 break;
 154         default:
 155                 kfree_skb(skb);
 156                 return -ENOTSUPP;
 157         }
 158         *pos++ = ie_len;
 159         *pos++ = flags;
 160         *pos++ = hop_count;
 161         *pos++ = ttl;
 162         if (action == MPATH_PREP) {
 163                 memcpy(pos, target, ETH_ALEN);
 164                 pos += ETH_ALEN;
 165                 put_unaligned_le32(target_sn, pos);
 166                 pos += 4;
 167         } else {
 168                 if (action == MPATH_PREQ) {
 169                         put_unaligned_le32(preq_id, pos);
 170                         pos += 4;
 171                 }
 172                 memcpy(pos, orig_addr, ETH_ALEN);
 173                 pos += ETH_ALEN;
 174                 put_unaligned_le32(orig_sn, pos);
 175                 pos += 4;
 176         }
 177         put_unaligned_le32(lifetime, pos); /* interval for RANN */
 178         pos += 4;
 179         put_unaligned_le32(metric, pos);
 180         pos += 4;
 181         if (action == MPATH_PREQ) {
 182                 *pos++ = 1; /* destination count */
 183                 *pos++ = target_flags;
 184                 memcpy(pos, target, ETH_ALEN);
 185                 pos += ETH_ALEN;
 186                 put_unaligned_le32(target_sn, pos);
 187                 pos += 4;
 188         } else if (action == MPATH_PREP) {
 189                 memcpy(pos, orig_addr, ETH_ALEN);
 190                 pos += ETH_ALEN;
 191                 put_unaligned_le32(orig_sn, pos);
 192                 pos += 4;
 193         }
 194
 195         ieee80211_tx_skb(sdata, skb);
 196         return 0;
 197 }
 198
 199
 200 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 201  *  headroom in case the frame is encrypted. */
 202 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 203                 struct sk_buff *skb)
 204 {
 205         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 206         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 207
 208         skb_reset_mac_header(skb);
 209         skb_reset_network_header(skb);
 210         skb_reset_transport_header(skb);
 211
 212         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 213         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 214         skb->priority = 7;
 215
 216         info->control.vif = &sdata->vif;
 217         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 218         ieee80211_set_qos_hdr(sdata, skb);
 219         ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
 220 }
 221
 222 /**
 223  * mesh_path_error_tx - Sends a PERR mesh management frame
 224  *
 225  * @ttl: allowed remaining hops
 226  * @target: broken destination
 227  * @target_sn: SN of the broken destination
 228  * @target_rcode: reason code for this PERR
 229  * @ra: node this frame is addressed to
 230  * @sdata: local mesh subif
 231  *
 232  * Note: This function may be called with driver locks taken that the driver
 233  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 234  * frame directly but add it to the pending queue instead.
 235  */
 236 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 237                        u8 ttl, const u8 *target, u32 target_sn,
 238                        u16 target_rcode, const u8 *ra)
 239 {
 240         struct ieee80211_local *local = sdata->local;
 241         struct sk_buff *skb;
 242         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 243         struct ieee80211_mgmt *mgmt;
 244         u8 *pos, ie_len;
 245         int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 246                       sizeof(mgmt->u.action.u.mesh_action);
 247
 248         if (time_before(jiffies, ifmsh->next_perr))
 249                 return -EAGAIN;
 250
 251         skb = dev_alloc_skb(local->tx_headroom +
 252                             sdata->encrypt_headroom +
 253                             IEEE80211_ENCRYPT_TAILROOM +
 254                             hdr_len +
 255                             2 + 15 /* PERR IE */);
 256         if (!skb)
 257                 return -1;
 258         skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom);
 259         mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 260         memset(mgmt, 0, hdr_len);
 261         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 262                                           IEEE80211_STYPE_ACTION);
 263
 264         memcpy(mgmt->da, ra, ETH_ALEN);
 265         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 266         /* BSSID == SA */
 267         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 268         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 269         mgmt->u.action.u.mesh_action.action_code =
 270                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 271         ie_len = 15;
 272         pos = skb_put(skb, 2 + ie_len);
 273         *pos++ = WLAN_EID_PERR;
 274         *pos++ = ie_len;
 275         /* ttl */
 276         *pos++ = ttl;
 277         /* number of destinations */
 278         *pos++ = 1;
 279         /* Flags field has AE bit only as defined in
 280          * sec 8.4.2.117 IEEE802.11-2012
 281          */
 282         *pos = 0;
 283         pos++;
 284         memcpy(pos, target, ETH_ALEN);
 285         pos += ETH_ALEN;
 286         put_unaligned_le32(target_sn, pos);
 287         pos += 4;
 288         put_unaligned_le16(target_rcode, pos);
 289
 290         /* see note in function header */
 291         prepare_frame_for_deferred_tx(sdata, skb);
 292         ifmsh->next_perr = TU_TO_EXP_TIME(
 293                                    ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 294         ieee80211_add_pending_skb(local, skb);
 295         return 0;
 296 }
 297
 298 void ieee80211s_update_metric(struct ieee80211_local *local,
 299                 struct sta_info *sta, struct sk_buff *skb)
 300 {
 301         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 302         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 303         int failed;
 304
 305         if (!ieee80211_is_data(hdr->frame_control))
 306                 return;
 307
 308         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 309
 310         /* moving average, scaled to 100 */
 311         sta->mesh->fail_avg =
 312                 ((80 * sta->mesh->fail_avg + 5) / 100 + 20 * failed);
 313         if (sta->mesh->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         /* Try to get rate based on HW/SW RC algorithm.
 330          * Rate is returned in units of Kbps, correct this
 331          * to comply with airtime calculation units
 332          * Round up in case we get rate < 100Kbps
 333          */
 334         rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
 335
 336         if (rate) {
 337                 err = 0;
 338         } else {
 339                 if (sta->mesh->fail_avg >= 100)
 340                         return MAX_METRIC;
 341
 342                 sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
 343                 rate = cfg80211_calculate_bitrate(&rinfo);
 344                 if (WARN_ON(!rate))
 345                         return MAX_METRIC;
 346
 347                 err = (sta->mesh->fail_avg << ARITH_SHIFT) / 100;
 348         }
 349
 350         /* bitrate is in units of 100 Kbps, while we need rate in units of
 351          * 1Mbps. This will be corrected on tx_time computation.
 352          */
 353         tx_time = (device_constant + 10 * test_frame_len / rate);
 354         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 355         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
 356         return (u32)result;
 357 }
 358
 359 /**
 360  * hwmp_route_info_get - Update routing info to originator and transmitter
 361  *
 362  * @sdata: local mesh subif
 363  * @mgmt: mesh management frame
 364  * @hwmp_ie: hwmp information element (PREP or PREQ)
 365  * @action: type of hwmp ie
 366  *
 367  * This function updates the path routing information to the originator and the
 368  * transmitter of a HWMP PREQ or PREP frame.
 369  *
 370  * Returns: metric to frame originator or 0 if the frame should not be further
 371  * processed
 372  *
 373  * Notes: this function is the only place (besides user-provided info) where
 374  * path routing information is updated.
 375  */
 376 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 377                                struct ieee80211_mgmt *mgmt,
 378                                const u8 *hwmp_ie, enum mpath_frame_type action)
 379 {
 380         struct ieee80211_local *local = sdata->local;
 381         struct mesh_path *mpath;
 382         struct sta_info *sta;
 383         bool fresh_info;
 384         const u8 *orig_addr, *ta;
 385         u32 orig_sn, orig_metric;
 386         unsigned long orig_lifetime, exp_time;
 387         u32 last_hop_metric, new_metric;
 388         bool process = true;
 389
 390         rcu_read_lock();
 391         sta = sta_info_get(sdata, mgmt->sa);
 392         if (!sta) {
 393                 rcu_read_unlock();
 394                 return 0;
 395         }
 396
 397         last_hop_metric = airtime_link_metric_get(local, sta);
 398         /* Update and check originator routing info */
 399         fresh_info = true;
 400
 401         switch (action) {
 402         case MPATH_PREQ:
 403                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 404                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 405                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 406                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 407                 break;
 408         case MPATH_PREP:
 409                 /* Originator here refers to the MP that was the target in the
 410                  * Path Request. We divert from the nomenclature in the draft
 411                  * so that we can easily use a single function to gather path
 412                  * information from both PREQ and PREP frames.
 413                  */
 414                 orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 415                 orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 416                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 417                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 418                 break;
 419         default:
 420                 rcu_read_unlock();
 421                 return 0;
 422         }
 423         new_metric = orig_metric + last_hop_metric;
 424         if (new_metric < orig_metric)
 425                 new_metric = MAX_METRIC;
 426         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 427
 428         if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 429                 /* This MP is the originator, we are not interested in this
 430                  * frame, except for updating transmitter's path info.
 431                  */
 432                 process = false;
 433                 fresh_info = false;
 434         } else {
 435                 mpath = mesh_path_lookup(sdata, orig_addr);
 436                 if (mpath) {
 437                         spin_lock_bh(&mpath->state_lock);
 438                         if (mpath->flags & MESH_PATH_FIXED)
 439                                 fresh_info = false;
 440                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 441                             (mpath->flags & MESH_PATH_SN_VALID)) {
 442                                 if (SN_GT(mpath->sn, orig_sn) ||
 443                                     (mpath->sn == orig_sn &&
 444                                      new_metric >= mpath->metric)) {
 445                                         process = false;
 446                                         fresh_info = false;
 447                                 }
 448                         } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 449                                 bool have_sn, newer_sn, bounced;
 450
 451                                 have_sn = mpath->flags & MESH_PATH_SN_VALID;
 452                                 newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 453                                 bounced = have_sn &&
 454                                           (SN_DELTA(orig_sn, mpath->sn) >
 455                                                         MAX_SANE_SN_DELTA);
 456
 457                                 if (!have_sn || newer_sn) {
 458                                         /* if SN is newer than what we had
 459                                          * then we can take it */;
 460                                 } else if (bounced) {
 461                                         /* if SN is way different than what
 462                                          * we had then assume the other side
 463                                          * rebooted or restarted */;
 464                                 } else {
 465                                         process = false;
 466                                         fresh_info = false;
 467                                 }
 468                         }
 469                 } else {
 470                         mpath = mesh_path_add(sdata, orig_addr);
 471                         if (IS_ERR(mpath)) {
 472                                 rcu_read_unlock();
 473                                 return 0;
 474                         }
 475                         spin_lock_bh(&mpath->state_lock);
 476                 }
 477
 478                 if (fresh_info) {
 479                         mesh_path_assign_nexthop(mpath, sta);
 480                         mpath->flags |= MESH_PATH_SN_VALID;
 481                         mpath->metric = new_metric;
 482                         mpath->sn = orig_sn;
 483                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 484                                           ?  mpath->exp_time : exp_time;
 485                         mesh_path_activate(mpath);
 486                         spin_unlock_bh(&mpath->state_lock);
 487                         mesh_path_tx_pending(mpath);
 488                         /* draft says preq_id should be saved to, but there does
 489                          * not seem to be any use for it, skipping by now
 490                          */
 491                 } else
 492                         spin_unlock_bh(&mpath->state_lock);
 493         }
 494
 495         /* Update and check transmitter routing info */
 496         ta = mgmt->sa;
 497         if (ether_addr_equal(orig_addr, ta))
 498                 fresh_info = false;
 499         else {
 500                 fresh_info = true;
 501
 502                 mpath = mesh_path_lookup(sdata, ta);
 503                 if (mpath) {
 504                         spin_lock_bh(&mpath->state_lock);
 505                         if ((mpath->flags & MESH_PATH_FIXED) ||
 506                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 507                                         (last_hop_metric > mpath->metric)))
 508                                 fresh_info = false;
 509                 } else {
 510                         mpath = mesh_path_add(sdata, ta);
 511                         if (IS_ERR(mpath)) {
 512                                 rcu_read_unlock();
 513                                 return 0;
 514                         }
 515                         spin_lock_bh(&mpath->state_lock);
 516                 }
 517
 518                 if (fresh_info) {
 519                         mesh_path_assign_nexthop(mpath, sta);
 520                         mpath->metric = last_hop_metric;
 521                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 522                                           ?  mpath->exp_time : exp_time;
 523                         mesh_path_activate(mpath);
 524                         spin_unlock_bh(&mpath->state_lock);
 525                         mesh_path_tx_pending(mpath);
 526                 } else
 527                         spin_unlock_bh(&mpath->state_lock);
 528         }
 529
 530         rcu_read_unlock();
 531
 532         return process ? new_metric : 0;
 533 }
 534
 535 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 536                                     struct ieee80211_mgmt *mgmt,
 537                                     const u8 *preq_elem, u32 orig_metric)
 538 {
 539         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 540         struct mesh_path *mpath = NULL;
 541         const u8 *target_addr, *orig_addr;
 542         const u8 *da;
 543         u8 target_flags, ttl, flags;
 544         u32 orig_sn, target_sn, lifetime, target_metric = 0;
 545         bool reply = false;
 546         bool forward = true;
 547         bool root_is_gate;
 548
 549         /* Update target SN, if present */
 550         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 551         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 552         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 553         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 554         target_flags = PREQ_IE_TARGET_F(preq_elem);
 555         /* Proactive PREQ gate announcements */
 556         flags = PREQ_IE_FLAGS(preq_elem);
 557         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 558
 559         mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 560
 561         if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 562                 mhwmp_dbg(sdata, "PREQ is for us\n");
 563                 forward = false;
 564                 reply = true;
 565                 target_metric = 0;
 566                 if (time_after(jiffies, ifmsh->last_sn_update +
 567                                         net_traversal_jiffies(sdata)) ||
 568                     time_before(jiffies, ifmsh->last_sn_update)) {
 569                         ++ifmsh->sn;
 570                         ifmsh->last_sn_update = jiffies;
 571                 }
 572                 target_sn = ifmsh->sn;
 573         } else if (is_broadcast_ether_addr(target_addr) &&
 574                    (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 575                 rcu_read_lock();
 576                 mpath = mesh_path_lookup(sdata, orig_addr);
 577                 if (mpath) {
 578                         if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 579                                 reply = true;
 580                                 target_addr = sdata->vif.addr;
 581                                 target_sn = ++ifmsh->sn;
 582                                 target_metric = 0;
 583                                 ifmsh->last_sn_update = jiffies;
 584                         }
 585                         if (root_is_gate)
 586                                 mesh_path_add_gate(mpath);
 587                 }
 588                 rcu_read_unlock();
 589         } else {
 590                 rcu_read_lock();
 591                 mpath = mesh_path_lookup(sdata, target_addr);
 592                 if (mpath) {
 593                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 594                                         SN_LT(mpath->sn, target_sn)) {
 595                                 mpath->sn = target_sn;
 596                                 mpath->flags |= MESH_PATH_SN_VALID;
 597                         } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 598                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 599                                 reply = true;
 600                                 target_metric = mpath->metric;
 601                                 target_sn = mpath->sn;
 602                                 /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 603                                 target_flags |= IEEE80211_PREQ_TO_FLAG;
 604                         }
 605                 }
 606                 rcu_read_unlock();
 607         }
 608
 609         if (reply) {
 610                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 611                 ttl = ifmsh->mshcfg.element_ttl;
 612                 if (ttl != 0) {
 613                         mhwmp_dbg(sdata, "replying to the PREQ\n");
 614                         mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 615                                                orig_sn, 0, target_addr,
 616                                                target_sn, mgmt->sa, 0, ttl,
 617                                                lifetime, target_metric, 0,
 618                                                sdata);
 619                 } else {
 620                         ifmsh->mshstats.dropped_frames_ttl++;
 621                 }
 622         }
 623
 624         if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 625                 u32 preq_id;
 626                 u8 hopcount;
 627
 628                 ttl = PREQ_IE_TTL(preq_elem);
 629                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 630                 if (ttl <= 1) {
 631                         ifmsh->mshstats.dropped_frames_ttl++;
 632                         return;
 633                 }
 634                 mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 635                 --ttl;
 636                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 637                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 638                 da = (mpath && mpath->is_root) ?
 639                         mpath->rann_snd_addr : broadcast_addr;
 640
 641                 if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 642                         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 643                         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 644                 }
 645
 646                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 647                                        orig_sn, target_flags, target_addr,
 648                                        target_sn, da, hopcount, ttl, lifetime,
 649                                        orig_metric, preq_id, sdata);
 650                 if (!is_multicast_ether_addr(da))
 651                         ifmsh->mshstats.fwded_unicast++;
 652                 else
 653                         ifmsh->mshstats.fwded_mcast++;
 654                 ifmsh->mshstats.fwded_frames++;
 655         }
 656 }
 657
 658
 659 static inline struct sta_info *
 660 next_hop_deref_protected(struct mesh_path *mpath)
 661 {
 662         return rcu_dereference_protected(mpath->next_hop,
 663                                          lockdep_is_held(&mpath->state_lock));
 664 }
 665
 666
 667 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 668                                     struct ieee80211_mgmt *mgmt,
 669                                     const u8 *prep_elem, u32 metric)
 670 {
 671         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 672         struct mesh_path *mpath;
 673         const u8 *target_addr, *orig_addr;
 674         u8 ttl, hopcount, flags;
 675         u8 next_hop[ETH_ALEN];
 676         u32 target_sn, orig_sn, lifetime;
 677
 678         mhwmp_dbg(sdata, "received PREP from %pM\n",
 679                   PREP_IE_TARGET_ADDR(prep_elem));
 680
 681         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 682         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 683                 /* destination, no forwarding required */
 684                 return;
 685
 686         if (!ifmsh->mshcfg.dot11MeshForwarding)
 687                 return;
 688
 689         ttl = PREP_IE_TTL(prep_elem);
 690         if (ttl <= 1) {
 691                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 692                 return;
 693         }
 694
 695         rcu_read_lock();
 696         mpath = mesh_path_lookup(sdata, orig_addr);
 697         if (mpath)
 698                 spin_lock_bh(&mpath->state_lock);
 699         else
 700                 goto fail;
 701         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 702                 spin_unlock_bh(&mpath->state_lock);
 703                 goto fail;
 704         }
 705         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 706         spin_unlock_bh(&mpath->state_lock);
 707         --ttl;
 708         flags = PREP_IE_FLAGS(prep_elem);
 709         lifetime = PREP_IE_LIFETIME(prep_elem);
 710         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 711         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 712         target_sn = PREP_IE_TARGET_SN(prep_elem);
 713         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 714
 715         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 716                                target_addr, target_sn, next_hop, hopcount,
 717                                ttl, lifetime, metric, 0, sdata);
 718         rcu_read_unlock();
 719
 720         sdata->u.mesh.mshstats.fwded_unicast++;
 721         sdata->u.mesh.mshstats.fwded_frames++;
 722         return;
 723
 724 fail:
 725         rcu_read_unlock();
 726         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 727 }
 728
 729 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 730                                     struct ieee80211_mgmt *mgmt,
 731                                     const u8 *perr_elem)
 732 {
 733         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 734         struct mesh_path *mpath;
 735         u8 ttl;
 736         const u8 *ta, *target_addr;
 737         u32 target_sn;
 738         u16 target_rcode;
 739
 740         ta = mgmt->sa;
 741         ttl = PERR_IE_TTL(perr_elem);
 742         if (ttl <= 1) {
 743                 ifmsh->mshstats.dropped_frames_ttl++;
 744                 return;
 745         }
 746         ttl--;
 747         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 748         target_sn = PERR_IE_TARGET_SN(perr_elem);
 749         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 750
 751         rcu_read_lock();
 752         mpath = mesh_path_lookup(sdata, target_addr);
 753         if (mpath) {
 754                 struct sta_info *sta;
 755
 756                 spin_lock_bh(&mpath->state_lock);
 757                 sta = next_hop_deref_protected(mpath);
 758                 if (mpath->flags & MESH_PATH_ACTIVE &&
 759                     ether_addr_equal(ta, sta->sta.addr) &&
 760                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 761                     SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 762                         mpath->flags &= ~MESH_PATH_ACTIVE;
 763                         if (target_sn != 0)
 764                                 mpath->sn = target_sn;
 765                         else
 766                                 mpath->sn += 1;
 767                         spin_unlock_bh(&mpath->state_lock);
 768                         if (!ifmsh->mshcfg.dot11MeshForwarding)
 769                                 goto endperr;
 770                         mesh_path_error_tx(sdata, ttl, target_addr,
 771                                            target_sn, target_rcode,
 772                                            broadcast_addr);
 773                 } else
 774                         spin_unlock_bh(&mpath->state_lock);
 775         }
 776 endperr:
 777         rcu_read_unlock();
 778 }
 779
 780 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 781                                     struct ieee80211_mgmt *mgmt,
 782                                     const struct ieee80211_rann_ie *rann)
 783 {
 784         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 785         struct ieee80211_local *local = sdata->local;
 786         struct sta_info *sta;
 787         struct mesh_path *mpath;
 788         u8 ttl, flags, hopcount;
 789         const u8 *orig_addr;
 790         u32 orig_sn, metric, metric_txsta, interval;
 791         bool root_is_gate;
 792
 793         ttl = rann->rann_ttl;
 794         flags = rann->rann_flags;
 795         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 796         orig_addr = rann->rann_addr;
 797         orig_sn = le32_to_cpu(rann->rann_seq);
 798         interval = le32_to_cpu(rann->rann_interval);
 799         hopcount = rann->rann_hopcount;
 800         hopcount++;
 801         metric = le32_to_cpu(rann->rann_metric);
 802
 803         /*  Ignore our own RANNs */
 804         if (ether_addr_equal(orig_addr, sdata->vif.addr))
 805                 return;
 806
 807         mhwmp_dbg(sdata,
 808                   "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 809                   orig_addr, mgmt->sa, root_is_gate);
 810
 811         rcu_read_lock();
 812         sta = sta_info_get(sdata, mgmt->sa);
 813         if (!sta) {
 814                 rcu_read_unlock();
 815                 return;
 816         }
 817
 818         metric_txsta = airtime_link_metric_get(local, sta);
 819
 820         mpath = mesh_path_lookup(sdata, orig_addr);
 821         if (!mpath) {
 822                 mpath = mesh_path_add(sdata, orig_addr);
 823                 if (IS_ERR(mpath)) {
 824                         rcu_read_unlock();
 825                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 826                         return;
 827                 }
 828         }
 829
 830         if (!(SN_LT(mpath->sn, orig_sn)) &&
 831             !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 832                 rcu_read_unlock();
 833                 return;
 834         }
 835
 836         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 837              (time_after(jiffies, mpath->last_preq_to_root +
 838                                   root_path_confirmation_jiffies(sdata)) ||
 839              time_before(jiffies, mpath->last_preq_to_root))) &&
 840              !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 841                 mhwmp_dbg(sdata,
 842                           "time to refresh root mpath %pM\n",
 843                           orig_addr);
 844                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 845                 mpath->last_preq_to_root = jiffies;
 846         }
 847
 848         mpath->sn = orig_sn;
 849         mpath->rann_metric = metric + metric_txsta;
 850         mpath->is_root = true;
 851         /* Recording RANNs sender address to send individually
 852          * addressed PREQs destined for root mesh STA */
 853         memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 854
 855         if (root_is_gate)
 856                 mesh_path_add_gate(mpath);
 857
 858         if (ttl <= 1) {
 859                 ifmsh->mshstats.dropped_frames_ttl++;
 860                 rcu_read_unlock();
 861                 return;
 862         }
 863         ttl--;
 864
 865         if (ifmsh->mshcfg.dot11MeshForwarding) {
 866                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 867                                        orig_sn, 0, NULL, 0, broadcast_addr,
 868                                        hopcount, ttl, interval,
 869                                        metric + metric_txsta, 0, sdata);
 870         }
 871
 872         rcu_read_unlock();
 873 }
 874
 875
 876 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 877                             struct ieee80211_mgmt *mgmt, size_t len)
 878 {
 879         struct ieee802_11_elems elems;
 880         size_t baselen;
 881         u32 path_metric;
 882         struct sta_info *sta;
 883
 884         /* need action_code */
 885         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 886                 return;
 887
 888         rcu_read_lock();
 889         sta = sta_info_get(sdata, mgmt->sa);
 890         if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 891                 rcu_read_unlock();
 892                 return;
 893         }
 894         rcu_read_unlock();
 895
 896         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 897         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 898                                len - baselen, false, &elems);
 899
 900         if (elems.preq) {
 901                 if (elems.preq_len != 37)
 902                         /* Right now we support just 1 destination and no AE */
 903                         return;
 904                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 905                                                   MPATH_PREQ);
 906                 if (path_metric)
 907                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 908                                                 path_metric);
 909         }
 910         if (elems.prep) {
 911                 if (elems.prep_len != 31)
 912                         /* Right now we support no AE */
 913                         return;
 914                 path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 915                                                   MPATH_PREP);
 916                 if (path_metric)
 917                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 918                                                 path_metric);
 919         }
 920         if (elems.perr) {
 921                 if (elems.perr_len != 15)
 922                         /* Right now we support only one destination per PERR */
 923                         return;
 924                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 925         }
 926         if (elems.rann)
 927                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 928 }
 929
 930 /**
 931  * mesh_queue_preq - queue a PREQ to a given destination
 932  *
 933  * @mpath: mesh path to discover
 934  * @flags: special attributes of the PREQ to be sent
 935  *
 936  * Locking: the function must be called from within a rcu read lock block.
 937  *
 938  */
 939 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 940 {
 941         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 942         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 943         struct mesh_preq_queue *preq_node;
 944
 945         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 946         if (!preq_node) {
 947                 mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 948                 return;
 949         }
 950
 951         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 952         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 953                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 954                 kfree(preq_node);
 955                 if (printk_ratelimit())
 956                         mhwmp_dbg(sdata, "PREQ node queue full\n");
 957                 return;
 958         }
 959
 960         spin_lock(&mpath->state_lock);
 961         if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 962                 spin_unlock(&mpath->state_lock);
 963                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 964                 kfree(preq_node);
 965                 return;
 966         }
 967
 968         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 969         preq_node->flags = flags;
 970
 971         mpath->flags |= MESH_PATH_REQ_QUEUED;
 972         spin_unlock(&mpath->state_lock);
 973
 974         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 975         ++ifmsh->preq_queue_len;
 976         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 977
 978         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 979                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 980
 981         else if (time_before(jiffies, ifmsh->last_preq)) {
 982                 /* avoid long wait if did not send preqs for a long time
 983                  * and jiffies wrapped around
 984                  */
 985                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 986                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 987         } else
 988                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 989                                                 min_preq_int_jiff(sdata));
 990 }
 991
 992 /**
 993  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 994  *
 995  * @sdata: local mesh subif
 996  */
 997 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 998 {
 999         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1000         struct mesh_preq_queue *preq_node;
1001         struct mesh_path *mpath;
1002         u8 ttl, target_flags = 0;
1003         const u8 *da;
1004         u32 lifetime;
1005
1006         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1007         if (!ifmsh->preq_queue_len ||
1008                 time_before(jiffies, ifmsh->last_preq +
1009                                 min_preq_int_jiff(sdata))) {
1010                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1011                 return;
1012         }
1013
1014         preq_node = list_first_entry(&ifmsh->preq_queue.list,
1015                         struct mesh_preq_queue, list);
1016         list_del(&preq_node->list);
1017         --ifmsh->preq_queue_len;
1018         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1019
1020         rcu_read_lock();
1021         mpath = mesh_path_lookup(sdata, preq_node->dst);
1022         if (!mpath)
1023                 goto enddiscovery;
1024
1025         spin_lock_bh(&mpath->state_lock);
1026         if (mpath->flags & MESH_PATH_DELETED) {
1027                 spin_unlock_bh(&mpath->state_lock);
1028                 goto enddiscovery;
1029         }
1030         mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1031         if (preq_node->flags & PREQ_Q_F_START) {
1032                 if (mpath->flags & MESH_PATH_RESOLVING) {
1033                         spin_unlock_bh(&mpath->state_lock);
1034                         goto enddiscovery;
1035                 } else {
1036                         mpath->flags &= ~MESH_PATH_RESOLVED;
1037                         mpath->flags |= MESH_PATH_RESOLVING;
1038                         mpath->discovery_retries = 0;
1039                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
1040                 }
1041         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1042                         mpath->flags & MESH_PATH_RESOLVED) {
1043                 mpath->flags &= ~MESH_PATH_RESOLVING;
1044                 spin_unlock_bh(&mpath->state_lock);
1045                 goto enddiscovery;
1046         }
1047
1048         ifmsh->last_preq = jiffies;
1049
1050         if (time_after(jiffies, ifmsh->last_sn_update +
1051                                 net_traversal_jiffies(sdata)) ||
1052             time_before(jiffies, ifmsh->last_sn_update)) {
1053                 ++ifmsh->sn;
1054                 sdata->u.mesh.last_sn_update = jiffies;
1055         }
1056         lifetime = default_lifetime(sdata);
1057         ttl = sdata->u.mesh.mshcfg.element_ttl;
1058         if (ttl == 0) {
1059                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
1060                 spin_unlock_bh(&mpath->state_lock);
1061                 goto enddiscovery;
1062         }
1063
1064         if (preq_node->flags & PREQ_Q_F_REFRESH)
1065                 target_flags |= IEEE80211_PREQ_TO_FLAG;
1066         else
1067                 target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1068
1069         spin_unlock_bh(&mpath->state_lock);
1070         da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1071         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1072                                target_flags, mpath->dst, mpath->sn, da, 0,
1073                                ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1074         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1075
1076 enddiscovery:
1077         rcu_read_unlock();
1078         kfree(preq_node);
1079 }
1080
1081 /**
1082  * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1083  *
1084  * @skb: 802.11 frame to be sent
1085  * @sdata: network subif the frame will be sent through
1086  *
1087  * Lookup next hop for given skb and start path discovery if no
1088  * forwarding information is found.
1089  *
1090  * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1091  * skb is freeed here if no mpath could be allocated.
1092  */
1093 int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1094                          struct sk_buff *skb)
1095 {
1096         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1097         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1098         struct mesh_path *mpath;
1099         struct sk_buff *skb_to_free = NULL;
1100         u8 *target_addr = hdr->addr3;
1101         int err = 0;
1102
1103         /* Nulls are only sent to peers for PS and should be pre-addressed */
1104         if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1105                 return 0;
1106
1107         rcu_read_lock();
1108         err = mesh_nexthop_lookup(sdata, skb);
1109         if (!err)
1110                 goto endlookup;
1111
1112         /* no nexthop found, start resolving */
1113         mpath = mesh_path_lookup(sdata, target_addr);
1114         if (!mpath) {
1115                 mpath = mesh_path_add(sdata, target_addr);
1116                 if (IS_ERR(mpath)) {
1117                         mesh_path_discard_frame(sdata, skb);
1118                         err = PTR_ERR(mpath);
1119                         goto endlookup;
1120                 }
1121         }
1122
1123         if (!(mpath->flags & MESH_PATH_RESOLVING))
1124                 mesh_queue_preq(mpath, PREQ_Q_F_START);
1125
1126         if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1127                 skb_to_free = skb_dequeue(&mpath->frame_queue);
1128
1129         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1130         ieee80211_set_qos_hdr(sdata, skb);
1131         skb_queue_tail(&mpath->frame_queue, skb);
1132         err = -ENOENT;
1133         if (skb_to_free)
1134                 mesh_path_discard_frame(sdata, skb_to_free);
1135
1136 endlookup:
1137         rcu_read_unlock();
1138         return err;
1139 }
1140
1141 /**
1142  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1143  * this function is considered "using" the associated mpath, so preempt a path
1144  * refresh if this mpath expires soon.
1145  *
1146  * @skb: 802.11 frame to be sent
1147  * @sdata: network subif the frame will be sent through
1148  *
1149  * Returns: 0 if the next hop was found. Nonzero otherwise.
1150  */
1151 int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1152                         struct sk_buff *skb)
1153 {
1154         struct mesh_path *mpath;
1155         struct sta_info *next_hop;
1156         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1157         u8 *target_addr = hdr->addr3;
1158         int err = -ENOENT;
1159
1160         rcu_read_lock();
1161         mpath = mesh_path_lookup(sdata, target_addr);
1162
1163         if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1164                 goto endlookup;
1165
1166         if (time_after(jiffies,
1167                        mpath->exp_time -
1168                        msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1169             ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1170             !(mpath->flags & MESH_PATH_RESOLVING) &&
1171             !(mpath->flags & MESH_PATH_FIXED))
1172                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1173
1174         next_hop = rcu_dereference(mpath->next_hop);
1175         if (next_hop) {
1176                 memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1177                 memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1178                 ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1179                 err = 0;
1180         }
1181
1182 endlookup:
1183         rcu_read_unlock();
1184         return err;
1185 }
1186
1187 void mesh_path_timer(unsigned long data)
1188 {
1189         struct mesh_path *mpath = (void *) data;
1190         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1191         int ret;
1192
1193         if (sdata->local->quiescing)
1194                 return;
1195
1196         spin_lock_bh(&mpath->state_lock);
1197         if (mpath->flags & MESH_PATH_RESOLVED ||
1198                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1199                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1200                 spin_unlock_bh(&mpath->state_lock);
1201         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1202                 ++mpath->discovery_retries;
1203                 mpath->discovery_timeout *= 2;
1204                 mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1205                 spin_unlock_bh(&mpath->state_lock);
1206                 mesh_queue_preq(mpath, 0);
1207         } else {
1208                 mpath->flags &= ~(MESH_PATH_RESOLVING |
1209                                   MESH_PATH_RESOLVED |
1210                                   MESH_PATH_REQ_QUEUED);
1211                 mpath->exp_time = jiffies;
1212                 spin_unlock_bh(&mpath->state_lock);
1213                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1214                         ret = mesh_path_send_to_gates(mpath);
1215                         if (ret)
1216                                 mhwmp_dbg(sdata, "no gate was reachable\n");
1217                 } else
1218                         mesh_path_flush_pending(mpath);
1219         }
1220 }
1221
1222 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1223 {
1224         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1225         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1226         u8 flags, target_flags = 0;
1227
1228         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1229                         ? RANN_FLAG_IS_GATE : 0;
1230
1231         switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1232         case IEEE80211_PROACTIVE_RANN:
1233                 mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1234                                        ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1235                                        0, ifmsh->mshcfg.element_ttl,
1236                                        interval, 0, 0, sdata);
1237                 break;
1238         case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1239                 flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1240         case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1241                 interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1242                 target_flags |= IEEE80211_PREQ_TO_FLAG |
1243                                 IEEE80211_PREQ_USN_FLAG;
1244                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1245                                        ++ifmsh->sn, target_flags,
1246                                        (u8 *) broadcast_addr, 0, broadcast_addr,
1247                                        0, ifmsh->mshcfg.element_ttl, interval,
1248                                        0, ifmsh->preq_id++, sdata);
1249                 break;
1250         default:
1251                 mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1252                 return;
1253         }
1254 }