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 "wme.h"
  12 #include "mesh.h"
  13
  14 #ifdef CONFIG_MAC80211_VERBOSE_MHWMP_DEBUG
  15 #define mhwmp_dbg(fmt, args...) \
  16         printk(KERN_DEBUG "Mesh HWMP (%s): " fmt "\n", sdata->name, ##args)
  17 #else
  18 #define mhwmp_dbg(fmt, args...)   do { (void)(0); } while (0)
  19 #endif
  20
  21 #define TEST_FRAME_LEN  8192
  22 #define MAX_METRIC      0xffffffff
  23 #define ARITH_SHIFT     8
  24
  25 /* Number of frames buffered per destination for unresolved destinations */
  26 #define MESH_FRAME_QUEUE_LEN    10
  27 #define MAX_PREQ_QUEUE_LEN      64
  28
  29 /* Destination only */
  30 #define MP_F_DO 0x1
  31 /* Reply and forward */
  32 #define MP_F_RF 0x2
  33 /* Unknown Sequence Number */
  34 #define MP_F_USN    0x01
  35 /* Reason code Present */
  36 #define MP_F_RCODE  0x02
  37
  38 static void mesh_queue_preq(struct mesh_path *, u8);
  39
  40 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
  41 {
  42         if (ae)
  43                 offset += 6;
  44         return get_unaligned_le32(preq_elem + offset);
  45 }
  46
  47 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
  48 {
  49         if (ae)
  50                 offset += 6;
  51         return get_unaligned_le16(preq_elem + offset);
  52 }
  53
  54 /* HWMP IE processing macros */
  55 #define AE_F                    (1<<6)
  56 #define AE_F_SET(x)             (*x & AE_F)
  57 #define PREQ_IE_FLAGS(x)        (*(x))
  58 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  59 #define PREQ_IE_TTL(x)          (*(x + 2))
  60 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  61 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  62 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  63 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  64 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  65 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  66 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  67 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  68
  69
  70 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  71 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  72 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  73 #define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  74 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  75 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  76 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  77 #define PREP_IE_TARGET_ADDR(x)  (x + 3)
  78 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  79
  80 #define PERR_IE_TTL(x)          (*(x))
  81 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  82 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  83 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  84 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  85
  86 #define MSEC_TO_TU(x) (x*1000/1024)
  87 #define SN_GT(x, y) ((long) (y) - (long) (x) < 0)
  88 #define SN_LT(x, y) ((long) (x) - (long) (y) < 0)
  89
  90 #define net_traversal_jiffies(s) \
  91         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  92 #define default_lifetime(s) \
  93         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  94 #define min_preq_int_jiff(s) \
  95         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  96 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  97 #define disc_timeout_jiff(s) \
  98         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  99
 100 enum mpath_frame_type {
 101         MPATH_PREQ = 0,
 102         MPATH_PREP,
 103         MPATH_PERR,
 104         MPATH_RANN
 105 };
 106
 107 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 108
 109 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 110                 u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
 111                 __le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
 112                 __le32 lifetime, __le32 metric, __le32 preq_id,
 113                 struct ieee80211_sub_if_data *sdata)
 114 {
 115         struct ieee80211_local *local = sdata->local;
 116         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
 117         struct ieee80211_mgmt *mgmt;
 118         u8 *pos;
 119         int ie_len;
 120
 121         if (!skb)
 122                 return -1;
 123         skb_reserve(skb, local->hw.extra_tx_headroom);
 124         /* 25 is the size of the common mgmt part (24) plus the size of the
 125          * common action part (1)
 126          */
 127         mgmt = (struct ieee80211_mgmt *)
 128                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 129         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 130         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 131                                           IEEE80211_STYPE_ACTION);
 132
 133         memcpy(mgmt->da, da, ETH_ALEN);
 134         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 135         /* BSSID == SA */
 136         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 137         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 138         mgmt->u.action.u.mesh_action.action_code =
 139                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 140
 141         switch (action) {
 142         case MPATH_PREQ:
 143                 mhwmp_dbg("sending PREQ to %pM", target);
 144                 ie_len = 37;
 145                 pos = skb_put(skb, 2 + ie_len);
 146                 *pos++ = WLAN_EID_PREQ;
 147                 break;
 148         case MPATH_PREP:
 149                 mhwmp_dbg("sending PREP to %pM", target);
 150                 ie_len = 31;
 151                 pos = skb_put(skb, 2 + ie_len);
 152                 *pos++ = WLAN_EID_PREP;
 153                 break;
 154         case MPATH_RANN:
 155                 mhwmp_dbg("sending RANN from %pM", orig_addr);
 156                 ie_len = sizeof(struct ieee80211_rann_ie);
 157                 pos = skb_put(skb, 2 + ie_len);
 158                 *pos++ = WLAN_EID_RANN;
 159                 break;
 160         default:
 161                 kfree_skb(skb);
 162                 return -ENOTSUPP;
 163                 break;
 164         }
 165         *pos++ = ie_len;
 166         *pos++ = flags;
 167         *pos++ = hop_count;
 168         *pos++ = ttl;
 169         if (action == MPATH_PREP) {
 170                 memcpy(pos, target, ETH_ALEN);
 171                 pos += ETH_ALEN;
 172                 memcpy(pos, &target_sn, 4);
 173                 pos += 4;
 174         } else {
 175                 if (action == MPATH_PREQ) {
 176                         memcpy(pos, &preq_id, 4);
 177                         pos += 4;
 178                 }
 179                 memcpy(pos, orig_addr, ETH_ALEN);
 180                 pos += ETH_ALEN;
 181                 memcpy(pos, &orig_sn, 4);
 182                 pos += 4;
 183         }
 184         memcpy(pos, &lifetime, 4);      /* interval for RANN */
 185         pos += 4;
 186         memcpy(pos, &metric, 4);
 187         pos += 4;
 188         if (action == MPATH_PREQ) {
 189                 *pos++ = 1; /* destination count */
 190                 *pos++ = target_flags;
 191                 memcpy(pos, target, ETH_ALEN);
 192                 pos += ETH_ALEN;
 193                 memcpy(pos, &target_sn, 4);
 194                 pos += 4;
 195         } else if (action == MPATH_PREP) {
 196                 memcpy(pos, orig_addr, ETH_ALEN);
 197                 pos += ETH_ALEN;
 198                 memcpy(pos, &orig_sn, 4);
 199                 pos += 4;
 200         }
 201
 202         ieee80211_tx_skb(sdata, skb);
 203         return 0;
 204 }
 205
 206
 207 /*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 208  *  headroom in case the frame is encrypted. */
 209 static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 210                 struct sk_buff *skb)
 211 {
 212         struct ieee80211_local *local = sdata->local;
 213         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 214
 215         skb_set_mac_header(skb, 0);
 216         skb_set_network_header(skb, 0);
 217         skb_set_transport_header(skb, 0);
 218
 219         /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 220         skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 221         skb->priority = 7;
 222
 223         info->control.vif = &sdata->vif;
 224         ieee80211_set_qos_hdr(local, skb);
 225 }
 226
 227 /**
 228  * mesh_send_path error - Sends a PERR mesh management frame
 229  *
 230  * @target: broken destination
 231  * @target_sn: SN of the broken destination
 232  * @target_rcode: reason code for this PERR
 233  * @ra: node this frame is addressed to
 234  *
 235  * Note: This function may be called with driver locks taken that the driver
 236  * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 237  * frame directly but add it to the pending queue instead.
 238  */
 239 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 240                        __le16 target_rcode, const u8 *ra,
 241                        struct ieee80211_sub_if_data *sdata)
 242 {
 243         struct ieee80211_local *local = sdata->local;
 244         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
 245         struct ieee80211_mgmt *mgmt;
 246         u8 *pos;
 247         int ie_len;
 248
 249         if (!skb)
 250                 return -1;
 251         skb_reserve(skb, local->tx_headroom + local->hw.extra_tx_headroom);
 252         /* 25 is the size of the common mgmt part (24) plus the size of the
 253          * common action part (1)
 254          */
 255         mgmt = (struct ieee80211_mgmt *)
 256                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 257         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 258         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 259                                           IEEE80211_STYPE_ACTION);
 260
 261         memcpy(mgmt->da, ra, ETH_ALEN);
 262         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 263         /* BSSID == SA */
 264         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 265         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 266         mgmt->u.action.u.mesh_action.action_code =
 267                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 268         ie_len = 15;
 269         pos = skb_put(skb, 2 + ie_len);
 270         *pos++ = WLAN_EID_PERR;
 271         *pos++ = ie_len;
 272         /* ttl */
 273         *pos++ = ttl;
 274         /* number of destinations */
 275         *pos++ = 1;
 276         /*
 277          * flags bit, bit 1 is unset if we know the sequence number and
 278          * bit 2 is set if we have a reason code
 279          */
 280         *pos = 0;
 281         if (!target_sn)
 282                 *pos |= MP_F_USN;
 283         if (target_rcode)
 284                 *pos |= MP_F_RCODE;
 285         pos++;
 286         memcpy(pos, target, ETH_ALEN);
 287         pos += ETH_ALEN;
 288         memcpy(pos, &target_sn, 4);
 289         pos += 4;
 290         memcpy(pos, &target_rcode, 2);
 291
 292         /* see note in function header */
 293         prepare_frame_for_deferred_tx(sdata, skb);
 294         ieee80211_add_pending_skb(local, skb);
 295         return 0;
 296 }
 297
 298 void ieee80211s_update_metric(struct ieee80211_local *local,
 299                 struct sta_info *stainfo, 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         stainfo->fail_avg = ((80 * stainfo->fail_avg + 5) / 100 + 20 * failed);
 312         if (stainfo->fail_avg > 95)
 313                 mesh_plink_broken(stainfo);
 314 }
 315
 316 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 317                                    struct sta_info *sta)
 318 {
 319         struct ieee80211_supported_band *sband;
 320         /* This should be adjusted for each device */
 321         int device_constant = 1 << ARITH_SHIFT;
 322         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 323         int s_unit = 1 << ARITH_SHIFT;
 324         int rate, err;
 325         u32 tx_time, estimated_retx;
 326         u64 result;
 327
 328         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 329
 330         if (sta->fail_avg >= 100)
 331                 return MAX_METRIC;
 332
 333         if (sta->last_tx_rate.flags & IEEE80211_TX_RC_MCS)
 334                 return MAX_METRIC;
 335
 336         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 337
 338         /* bitrate is in units of 100 Kbps, while we need rate in units of
 339          * 1Mbps. This will be corrected on tx_time computation.
 340          */
 341         rate = sband->bitrates[sta->last_tx_rate.idx].bitrate;
 342         tx_time = (device_constant + 10 * test_frame_len / rate);
 343         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 344         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 345         return (u32)result;
 346 }
 347
 348 /**
 349  * hwmp_route_info_get - Update routing info to originator and transmitter
 350  *
 351  * @sdata: local mesh subif
 352  * @mgmt: mesh management frame
 353  * @hwmp_ie: hwmp information element (PREP or PREQ)
 354  *
 355  * This function updates the path routing information to the originator and the
 356  * transmitter of a HWMP PREQ or PREP frame.
 357  *
 358  * Returns: metric to frame originator or 0 if the frame should not be further
 359  * processed
 360  *
 361  * Notes: this function is the only place (besides user-provided info) where
 362  * path routing information is updated.
 363  */
 364 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 365                             struct ieee80211_mgmt *mgmt,
 366                             u8 *hwmp_ie, enum mpath_frame_type action)
 367 {
 368         struct ieee80211_local *local = sdata->local;
 369         struct mesh_path *mpath;
 370         struct sta_info *sta;
 371         bool fresh_info;
 372         u8 *orig_addr, *ta;
 373         u32 orig_sn, orig_metric;
 374         unsigned long orig_lifetime, exp_time;
 375         u32 last_hop_metric, new_metric;
 376         bool process = true;
 377
 378         rcu_read_lock();
 379         sta = sta_info_get(sdata, mgmt->sa);
 380         if (!sta) {
 381                 rcu_read_unlock();
 382                 return 0;
 383         }
 384
 385         last_hop_metric = airtime_link_metric_get(local, sta);
 386         /* Update and check originator routing info */
 387         fresh_info = true;
 388
 389         switch (action) {
 390         case MPATH_PREQ:
 391                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 392                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 393                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 394                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 395                 break;
 396         case MPATH_PREP:
 397                 /* Originator here refers to the MP that was the destination in
 398                  * the Path Request. The draft refers to that MP as the
 399                  * destination address, even though usually it is the origin of
 400                  * the PREP frame. 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_ORIG_ADDR(hwmp_ie);
 405                 orig_sn = PREP_IE_ORIG_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 (memcmp(orig_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 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 (memcmp(orig_addr, ta, ETH_ALEN) == 0)
 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;
 513         u8 *target_addr, *orig_addr;
 514         u8 target_flags, ttl;
 515         u32 orig_sn, target_sn, lifetime;
 516         bool reply = false;
 517         bool forward = true;
 518
 519         /* Update target SN, if present */
 520         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 521         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 522         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 523         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 524         target_flags = PREQ_IE_TARGET_F(preq_elem);
 525
 526         mhwmp_dbg("received PREQ from %pM", orig_addr);
 527
 528         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 529                 mhwmp_dbg("PREQ is for us");
 530                 forward = false;
 531                 reply = true;
 532                 metric = 0;
 533                 if (time_after(jiffies, ifmsh->last_sn_update +
 534                                         net_traversal_jiffies(sdata)) ||
 535                     time_before(jiffies, ifmsh->last_sn_update)) {
 536                         target_sn = ++ifmsh->sn;
 537                         ifmsh->last_sn_update = jiffies;
 538                 }
 539         } else {
 540                 rcu_read_lock();
 541                 mpath = mesh_path_lookup(target_addr, sdata);
 542                 if (mpath) {
 543                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 544                                         SN_LT(mpath->sn, target_sn)) {
 545                                 mpath->sn = target_sn;
 546                                 mpath->flags |= MESH_PATH_SN_VALID;
 547                         } else if ((!(target_flags & MP_F_DO)) &&
 548                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 549                                 reply = true;
 550                                 metric = mpath->metric;
 551                                 target_sn = mpath->sn;
 552                                 if (target_flags & MP_F_RF)
 553                                         target_flags |= MP_F_DO;
 554                                 else
 555                                         forward = false;
 556                         }
 557                 }
 558                 rcu_read_unlock();
 559         }
 560
 561         if (reply) {
 562                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 563                 ttl = ifmsh->mshcfg.element_ttl;
 564                 if (ttl != 0) {
 565                         mhwmp_dbg("replying to the PREQ");
 566                         mesh_path_sel_frame_tx(MPATH_PREP, 0, target_addr,
 567                                 cpu_to_le32(target_sn), 0, orig_addr,
 568                                 cpu_to_le32(orig_sn), mgmt->sa, 0, ttl,
 569                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 570                                 0, sdata);
 571                 } else
 572                         ifmsh->mshstats.dropped_frames_ttl++;
 573         }
 574
 575         if (forward) {
 576                 u32 preq_id;
 577                 u8 hopcount, flags;
 578
 579                 ttl = PREQ_IE_TTL(preq_elem);
 580                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 581                 if (ttl <= 1) {
 582                         ifmsh->mshstats.dropped_frames_ttl++;
 583                         return;
 584                 }
 585                 mhwmp_dbg("forwarding the PREQ from %pM", orig_addr);
 586                 --ttl;
 587                 flags = PREQ_IE_FLAGS(preq_elem);
 588                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 589                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 590                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 591                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 592                                 cpu_to_le32(target_sn), broadcast_addr,
 593                                 hopcount, ttl, cpu_to_le32(lifetime),
 594                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 595                                 sdata);
 596                 ifmsh->mshstats.fwded_mcast++;
 597                 ifmsh->mshstats.fwded_frames++;
 598         }
 599 }
 600
 601
 602 static inline struct sta_info *
 603 next_hop_deref_protected(struct mesh_path *mpath)
 604 {
 605         return rcu_dereference_protected(mpath->next_hop,
 606                                          lockdep_is_held(&mpath->state_lock));
 607 }
 608
 609
 610 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 611                                     struct ieee80211_mgmt *mgmt,
 612                                     u8 *prep_elem, u32 metric)
 613 {
 614         struct mesh_path *mpath;
 615         u8 *target_addr, *orig_addr;
 616         u8 ttl, hopcount, flags;
 617         u8 next_hop[ETH_ALEN];
 618         u32 target_sn, orig_sn, lifetime;
 619
 620         mhwmp_dbg("received PREP from %pM", PREP_IE_ORIG_ADDR(prep_elem));
 621
 622         /* Note that we divert from the draft nomenclature and denominate
 623          * destination to what the draft refers to as origininator. So in this
 624          * function destnation refers to the final destination of the PREP,
 625          * which corresponds with the originator of the PREQ which this PREP
 626          * replies
 627          */
 628         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 629         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0)
 630                 /* destination, no forwarding required */
 631                 return;
 632
 633         ttl = PREP_IE_TTL(prep_elem);
 634         if (ttl <= 1) {
 635                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 636                 return;
 637         }
 638
 639         rcu_read_lock();
 640         mpath = mesh_path_lookup(target_addr, sdata);
 641         if (mpath)
 642                 spin_lock_bh(&mpath->state_lock);
 643         else
 644                 goto fail;
 645         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 646                 spin_unlock_bh(&mpath->state_lock);
 647                 goto fail;
 648         }
 649         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 650         spin_unlock_bh(&mpath->state_lock);
 651         --ttl;
 652         flags = PREP_IE_FLAGS(prep_elem);
 653         lifetime = PREP_IE_LIFETIME(prep_elem);
 654         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 655         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 656         target_sn = PREP_IE_TARGET_SN(prep_elem);
 657         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 658
 659         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 660                 cpu_to_le32(orig_sn), 0, target_addr,
 661                 cpu_to_le32(target_sn), next_hop, hopcount,
 662                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 663                 0, sdata);
 664         rcu_read_unlock();
 665
 666         sdata->u.mesh.mshstats.fwded_unicast++;
 667         sdata->u.mesh.mshstats.fwded_frames++;
 668         return;
 669
 670 fail:
 671         rcu_read_unlock();
 672         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 673 }
 674
 675 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 676                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 677 {
 678         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 679         struct mesh_path *mpath;
 680         u8 ttl;
 681         u8 *ta, *target_addr;
 682         u32 target_sn;
 683         u16 target_rcode;
 684
 685         ta = mgmt->sa;
 686         ttl = PERR_IE_TTL(perr_elem);
 687         if (ttl <= 1) {
 688                 ifmsh->mshstats.dropped_frames_ttl++;
 689                 return;
 690         }
 691         ttl--;
 692         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 693         target_sn = PERR_IE_TARGET_SN(perr_elem);
 694         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 695
 696         rcu_read_lock();
 697         mpath = mesh_path_lookup(target_addr, sdata);
 698         if (mpath) {
 699                 spin_lock_bh(&mpath->state_lock);
 700                 if (mpath->flags & MESH_PATH_ACTIVE &&
 701                     memcmp(ta, next_hop_deref_protected(mpath)->sta.addr,
 702                                                         ETH_ALEN) == 0 &&
 703                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 704                     SN_GT(target_sn, mpath->sn))) {
 705                         mpath->flags &= ~MESH_PATH_ACTIVE;
 706                         mpath->sn = target_sn;
 707                         spin_unlock_bh(&mpath->state_lock);
 708                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 709                                            cpu_to_le16(target_rcode),
 710                                            broadcast_addr, sdata);
 711                 } else
 712                         spin_unlock_bh(&mpath->state_lock);
 713         }
 714         rcu_read_unlock();
 715 }
 716
 717 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 718                                 struct ieee80211_mgmt *mgmt,
 719                                 struct ieee80211_rann_ie *rann)
 720 {
 721         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 722         struct mesh_path *mpath;
 723         u8 ttl, flags, hopcount;
 724         u8 *orig_addr;
 725         u32 orig_sn, metric;
 726         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
 727         bool root_is_gate;
 728
 729         ttl = rann->rann_ttl;
 730         if (ttl <= 1) {
 731                 ifmsh->mshstats.dropped_frames_ttl++;
 732                 return;
 733         }
 734         ttl--;
 735         flags = rann->rann_flags;
 736         root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 737         orig_addr = rann->rann_addr;
 738         orig_sn = rann->rann_seq;
 739         hopcount = rann->rann_hopcount;
 740         hopcount++;
 741         metric = rann->rann_metric;
 742
 743         /*  Ignore our own RANNs */
 744         if (memcmp(orig_addr, sdata->vif.addr, ETH_ALEN) == 0)
 745                 return;
 746
 747         mhwmp_dbg("received RANN from %pM (is_gate=%d)", orig_addr,
 748                         root_is_gate);
 749
 750         rcu_read_lock();
 751         mpath = mesh_path_lookup(orig_addr, sdata);
 752         if (!mpath) {
 753                 mesh_path_add(orig_addr, sdata);
 754                 mpath = mesh_path_lookup(orig_addr, sdata);
 755                 if (!mpath) {
 756                         rcu_read_unlock();
 757                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 758                         return;
 759                 }
 760         }
 761
 762         if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 763              time_after(jiffies, mpath->exp_time - 1*HZ)) &&
 764              !(mpath->flags & MESH_PATH_FIXED)) {
 765                 mhwmp_dbg("%s time to refresh root mpath %pM", sdata->name,
 766                                                                orig_addr);
 767                 mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 768         }
 769
 770         if (mpath->sn < orig_sn) {
 771                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 772                                        cpu_to_le32(orig_sn),
 773                                        0, NULL, 0, broadcast_addr,
 774                                        hopcount, ttl, cpu_to_le32(interval),
 775                                        cpu_to_le32(metric + mpath->metric),
 776                                        0, sdata);
 777                 mpath->sn = orig_sn;
 778         }
 779         if (root_is_gate)
 780                 mesh_path_add_gate(mpath);
 781
 782         rcu_read_unlock();
 783 }
 784
 785
 786 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 787                             struct ieee80211_mgmt *mgmt,
 788                             size_t len)
 789 {
 790         struct ieee802_11_elems elems;
 791         size_t baselen;
 792         u32 last_hop_metric;
 793
 794         /* need action_code */
 795         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 796                 return;
 797
 798         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 799         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 800                         len - baselen, &elems);
 801
 802         if (elems.preq) {
 803                 if (elems.preq_len != 37)
 804                         /* Right now we support just 1 destination and no AE */
 805                         return;
 806                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 807                                                       MPATH_PREQ);
 808                 if (last_hop_metric)
 809                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 810                                                 last_hop_metric);
 811         }
 812         if (elems.prep) {
 813                 if (elems.prep_len != 31)
 814                         /* Right now we support no AE */
 815                         return;
 816                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 817                                                       MPATH_PREP);
 818                 if (last_hop_metric)
 819                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 820                                                 last_hop_metric);
 821         }
 822         if (elems.perr) {
 823                 if (elems.perr_len != 15)
 824                         /* Right now we support only one destination per PERR */
 825                         return;
 826                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 827         }
 828         if (elems.rann)
 829                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 830 }
 831
 832 /**
 833  * mesh_queue_preq - queue a PREQ to a given destination
 834  *
 835  * @mpath: mesh path to discover
 836  * @flags: special attributes of the PREQ to be sent
 837  *
 838  * Locking: the function must be called from within a rcu read lock block.
 839  *
 840  */
 841 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 842 {
 843         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 844         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 845         struct mesh_preq_queue *preq_node;
 846
 847         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 848         if (!preq_node) {
 849                 mhwmp_dbg("could not allocate PREQ node");
 850                 return;
 851         }
 852
 853         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 854         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 855                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 856                 kfree(preq_node);
 857                 if (printk_ratelimit())
 858                         mhwmp_dbg("PREQ node queue full");
 859                 return;
 860         }
 861
 862         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 863         preq_node->flags = flags;
 864
 865         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 866         ++ifmsh->preq_queue_len;
 867         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 868
 869         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 870                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 871
 872         else if (time_before(jiffies, ifmsh->last_preq)) {
 873                 /* avoid long wait if did not send preqs for a long time
 874                  * and jiffies wrapped around
 875                  */
 876                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 877                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 878         } else
 879                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 880                                                 min_preq_int_jiff(sdata));
 881 }
 882
 883 /**
 884  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 885  *
 886  * @sdata: local mesh subif
 887  */
 888 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 889 {
 890         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 891         struct mesh_preq_queue *preq_node;
 892         struct mesh_path *mpath;
 893         u8 ttl, target_flags;
 894         u32 lifetime;
 895
 896         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 897         if (!ifmsh->preq_queue_len ||
 898                 time_before(jiffies, ifmsh->last_preq +
 899                                 min_preq_int_jiff(sdata))) {
 900                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 901                 return;
 902         }
 903
 904         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 905                         struct mesh_preq_queue, list);
 906         list_del(&preq_node->list);
 907         --ifmsh->preq_queue_len;
 908         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 909
 910         rcu_read_lock();
 911         mpath = mesh_path_lookup(preq_node->dst, sdata);
 912         if (!mpath)
 913                 goto enddiscovery;
 914
 915         spin_lock_bh(&mpath->state_lock);
 916         if (preq_node->flags & PREQ_Q_F_START) {
 917                 if (mpath->flags & MESH_PATH_RESOLVING) {
 918                         spin_unlock_bh(&mpath->state_lock);
 919                         goto enddiscovery;
 920                 } else {
 921                         mpath->flags &= ~MESH_PATH_RESOLVED;
 922                         mpath->flags |= MESH_PATH_RESOLVING;
 923                         mpath->discovery_retries = 0;
 924                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 925                 }
 926         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 927                         mpath->flags & MESH_PATH_RESOLVED) {
 928                 mpath->flags &= ~MESH_PATH_RESOLVING;
 929                 spin_unlock_bh(&mpath->state_lock);
 930                 goto enddiscovery;
 931         }
 932
 933         ifmsh->last_preq = jiffies;
 934
 935         if (time_after(jiffies, ifmsh->last_sn_update +
 936                                 net_traversal_jiffies(sdata)) ||
 937             time_before(jiffies, ifmsh->last_sn_update)) {
 938                 ++ifmsh->sn;
 939                 sdata->u.mesh.last_sn_update = jiffies;
 940         }
 941         lifetime = default_lifetime(sdata);
 942         ttl = sdata->u.mesh.mshcfg.element_ttl;
 943         if (ttl == 0) {
 944                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 945                 spin_unlock_bh(&mpath->state_lock);
 946                 goto enddiscovery;
 947         }
 948
 949         if (preq_node->flags & PREQ_Q_F_REFRESH)
 950                 target_flags = MP_F_DO;
 951         else
 952                 target_flags = MP_F_RF;
 953
 954         spin_unlock_bh(&mpath->state_lock);
 955         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
 956                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
 957                         cpu_to_le32(mpath->sn), broadcast_addr, 0,
 958                         ttl, cpu_to_le32(lifetime), 0,
 959                         cpu_to_le32(ifmsh->preq_id++), sdata);
 960         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 961
 962 enddiscovery:
 963         rcu_read_unlock();
 964         kfree(preq_node);
 965 }
 966
 967 /**
 968  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
 969  *
 970  * @skb: 802.11 frame to be sent
 971  * @sdata: network subif the frame will be sent through
 972  *
 973  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 974  * found, the function will start a path discovery and queue the frame so it is
 975  * sent when the path is resolved. This means the caller must not free the skb
 976  * in this case.
 977  */
 978 int mesh_nexthop_lookup(struct sk_buff *skb,
 979                         struct ieee80211_sub_if_data *sdata)
 980 {
 981         struct sk_buff *skb_to_free = NULL;
 982         struct mesh_path *mpath;
 983         struct sta_info *next_hop;
 984         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 985         u8 *target_addr = hdr->addr3;
 986         int err = 0;
 987
 988         rcu_read_lock();
 989         mpath = mesh_path_lookup(target_addr, sdata);
 990
 991         if (!mpath) {
 992                 mesh_path_add(target_addr, sdata);
 993                 mpath = mesh_path_lookup(target_addr, sdata);
 994                 if (!mpath) {
 995                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 996                         err = -ENOSPC;
 997                         goto endlookup;
 998                 }
 999         }
1000
1001         if (mpath->flags & MESH_PATH_ACTIVE) {
1002                 if (time_after(jiffies,
1003                                mpath->exp_time -
1004                                msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1005                     !memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
1006                     !(mpath->flags & MESH_PATH_RESOLVING) &&
1007                     !(mpath->flags & MESH_PATH_FIXED)) {
1008                         mesh_queue_preq(mpath,
1009                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1010                 }
1011                 next_hop = rcu_dereference(mpath->next_hop);
1012                 if (next_hop)
1013                         memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1014                 else
1015                         err = -ENOENT;
1016         } else {
1017                 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1018                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
1019                         /* Start discovery only if it is not running yet */
1020                         mesh_queue_preq(mpath, PREQ_Q_F_START);
1021                 }
1022
1023                 if (skb_queue_len(&mpath->frame_queue) >=
1024                                 MESH_FRAME_QUEUE_LEN)
1025                         skb_to_free = skb_dequeue(&mpath->frame_queue);
1026
1027                 info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1028                 skb_queue_tail(&mpath->frame_queue, skb);
1029                 if (skb_to_free)
1030                         mesh_path_discard_frame(skb_to_free, sdata);
1031                 err = -ENOENT;
1032         }
1033
1034 endlookup:
1035         rcu_read_unlock();
1036         return err;
1037 }
1038
1039 void mesh_path_timer(unsigned long data)
1040 {
1041         struct mesh_path *mpath = (void *) data;
1042         struct ieee80211_sub_if_data *sdata = mpath->sdata;
1043         int ret;
1044
1045         if (sdata->local->quiescing)
1046                 return;
1047
1048         spin_lock_bh(&mpath->state_lock);
1049         if (mpath->flags & MESH_PATH_RESOLVED ||
1050                         (!(mpath->flags & MESH_PATH_RESOLVING))) {
1051                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1052                 spin_unlock_bh(&mpath->state_lock);
1053         } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1054                 ++mpath->discovery_retries;
1055                 mpath->discovery_timeout *= 2;
1056                 spin_unlock_bh(&mpath->state_lock);
1057                 mesh_queue_preq(mpath, 0);
1058         } else {
1059                 mpath->flags = 0;
1060                 mpath->exp_time = jiffies;
1061                 spin_unlock_bh(&mpath->state_lock);
1062                 if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1063                         ret = mesh_path_send_to_gates(mpath);
1064                         if (ret)
1065                                 mhwmp_dbg("no gate was reachable");
1066                 } else
1067                         mesh_path_flush_pending(mpath);
1068         }
1069 }
1070
1071 void
1072 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1073 {
1074         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1075         u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1076         u8 flags;
1077
1078         flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1079                         ? RANN_FLAG_IS_GATE : 0;
1080         mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1081                                cpu_to_le32(++ifmsh->sn),
1082                                0, NULL, 0, broadcast_addr,
1083                                0, sdata->u.mesh.mshcfg.element_ttl,
1084                                cpu_to_le32(interval), 0, 0, sdata);
1085 }