net/mac80211/mesh_hwmp.c

   1 /*
   2  * Copyright (c) 2008 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 "mesh.h"
  11
  12 #define TEST_FRAME_LEN  8192
  13 #define MAX_METRIC      0xffffffff
  14 #define ARITH_SHIFT     8
  15
  16 /* Number of frames buffered per destination for unresolved destinations */
  17 #define MESH_FRAME_QUEUE_LEN    10
  18 #define MAX_PREQ_QUEUE_LEN      64
  19
  20 /* Destination only */
  21 #define MP_F_DO 0x1
  22 /* Reply and forward */
  23 #define MP_F_RF 0x2
  24
  25 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
  26 {
  27         if (ae)
  28                 offset += 6;
  29         return get_unaligned_le32(preq_elem + offset);
  30 }
  31
  32 /* HWMP IE processing macros */
  33 #define AE_F                    (1<<6)
  34 #define AE_F_SET(x)             (*x & AE_F)
  35 #define PREQ_IE_FLAGS(x)        (*(x))
  36 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  37 #define PREQ_IE_TTL(x)          (*(x + 2))
  38 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  39 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  40 #define PREQ_IE_ORIG_DSN(x)     u32_field_get(x, 13, 0);
  41 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x));
  42 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x));
  43 #define PREQ_IE_DST_F(x)        (*(AE_F_SET(x) ? x + 32 : x + 26))
  44 #define PREQ_IE_DST_ADDR(x)     (AE_F_SET(x) ? x + 33 : x + 27)
  45 #define PREQ_IE_DST_DSN(x)      u32_field_get(x, 33, AE_F_SET(x));
  46
  47
  48 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  49 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  50 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  51 #define PREP_IE_ORIG_ADDR(x)    (x + 3)
  52 #define PREP_IE_ORIG_DSN(x)     u32_field_get(x, 9, 0);
  53 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x));
  54 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x));
  55 #define PREP_IE_DST_ADDR(x)     (AE_F_SET(x) ? x + 27 : x + 21)
  56 #define PREP_IE_DST_DSN(x)      u32_field_get(x, 27, AE_F_SET(x));
  57
  58 #define PERR_IE_DST_ADDR(x)     (x + 2)
  59 #define PERR_IE_DST_DSN(x)      u32_field_get(x, 8, 0);
  60
  61 #define MSEC_TO_TU(x) (x*1000/1024)
  62 #define DSN_GT(x, y) ((long) (y) - (long) (x) < 0)
  63 #define DSN_LT(x, y) ((long) (x) - (long) (y) < 0)
  64
  65 #define net_traversal_jiffies(s) \
  66         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  67 #define default_lifetime(s) \
  68         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  69 #define min_preq_int_jiff(s) \
  70         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  71 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  72 #define disc_timeout_jiff(s) \
  73         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  74
  75 enum mpath_frame_type {
  76         MPATH_PREQ = 0,
  77         MPATH_PREP,
  78         MPATH_PERR
  79 };
  80
  81 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
  82                 u8 *orig_addr, __le32 orig_dsn, u8 dst_flags, u8 *dst,
  83                 __le32 dst_dsn, u8 *da, u8 hop_count, u8 ttl, __le32 lifetime,
  84                 __le32 metric, __le32 preq_id, struct ieee80211_sub_if_data *sdata)
  85 {
  86         struct ieee80211_local *local = sdata->local;
  87         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
  88         struct ieee80211_mgmt *mgmt;
  89         u8 *pos;
  90         int ie_len;
  91
  92         if (!skb)
  93                 return -1;
  94         skb_reserve(skb, local->hw.extra_tx_headroom);
  95         /* 25 is the size of the common mgmt part (24) plus the size of the
  96          * common action part (1)
  97          */
  98         mgmt = (struct ieee80211_mgmt *)
  99                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 100         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 101         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 102                                           IEEE80211_STYPE_ACTION);
 103
 104         memcpy(mgmt->da, da, ETH_ALEN);
 105         memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
 106         /* BSSID is left zeroed, wildcard value */
 107         mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
 108         mgmt->u.action.u.mesh_action.action_code = action;
 109
 110         switch (action) {
 111         case MPATH_PREQ:
 112                 ie_len = 37;
 113                 pos = skb_put(skb, 2 + ie_len);
 114                 *pos++ = WLAN_EID_PREQ;
 115                 break;
 116         case MPATH_PREP:
 117                 ie_len = 31;
 118                 pos = skb_put(skb, 2 + ie_len);
 119                 *pos++ = WLAN_EID_PREP;
 120                 break;
 121         default:
 122                 kfree_skb(skb);
 123                 return -ENOTSUPP;
 124                 break;
 125         }
 126         *pos++ = ie_len;
 127         *pos++ = flags;
 128         *pos++ = hop_count;
 129         *pos++ = ttl;
 130         if (action == MPATH_PREQ) {
 131                 memcpy(pos, &preq_id, 4);
 132                 pos += 4;
 133         }
 134         memcpy(pos, orig_addr, ETH_ALEN);
 135         pos += ETH_ALEN;
 136         memcpy(pos, &orig_dsn, 4);
 137         pos += 4;
 138         memcpy(pos, &lifetime, 4);
 139         pos += 4;
 140         memcpy(pos, &metric, 4);
 141         pos += 4;
 142         if (action == MPATH_PREQ) {
 143                 /* destination count */
 144                 *pos++ = 1;
 145                 *pos++ = dst_flags;
 146         }
 147         memcpy(pos, dst, ETH_ALEN);
 148         pos += ETH_ALEN;
 149         memcpy(pos, &dst_dsn, 4);
 150
 151         ieee80211_tx_skb(sdata, skb, 1);
 152         return 0;
 153 }
 154
 155 /**
 156  * mesh_send_path error - Sends a PERR mesh management frame
 157  *
 158  * @dst: broken destination
 159  * @dst_dsn: dsn of the broken destination
 160  * @ra: node this frame is addressed to
 161  */
 162 int mesh_path_error_tx(u8 *dst, __le32 dst_dsn, u8 *ra,
 163                 struct ieee80211_sub_if_data *sdata)
 164 {
 165         struct ieee80211_local *local = sdata->local;
 166         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
 167         struct ieee80211_mgmt *mgmt;
 168         u8 *pos;
 169         int ie_len;
 170
 171         if (!skb)
 172                 return -1;
 173         skb_reserve(skb, local->hw.extra_tx_headroom);
 174         /* 25 is the size of the common mgmt part (24) plus the size of the
 175          * common action part (1)
 176          */
 177         mgmt = (struct ieee80211_mgmt *)
 178                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 179         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 180         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 181                                           IEEE80211_STYPE_ACTION);
 182
 183         memcpy(mgmt->da, ra, ETH_ALEN);
 184         memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
 185         /* BSSID is left zeroed, wildcard value */
 186         mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
 187         mgmt->u.action.u.mesh_action.action_code = MPATH_PERR;
 188         ie_len = 12;
 189         pos = skb_put(skb, 2 + ie_len);
 190         *pos++ = WLAN_EID_PERR;
 191         *pos++ = ie_len;
 192         /* mode flags, reserved */
 193         *pos++ = 0;
 194         /* number of destinations */
 195         *pos++ = 1;
 196         memcpy(pos, dst, ETH_ALEN);
 197         pos += ETH_ALEN;
 198         memcpy(pos, &dst_dsn, 4);
 199
 200         ieee80211_tx_skb(sdata, skb, 1);
 201         return 0;
 202 }
 203
 204 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 205                                    struct sta_info *sta)
 206 {
 207         struct ieee80211_supported_band *sband;
 208         /* This should be adjusted for each device */
 209         int device_constant = 1 << ARITH_SHIFT;
 210         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 211         int s_unit = 1 << ARITH_SHIFT;
 212         int rate, err;
 213         u32 tx_time, estimated_retx;
 214         u64 result;
 215
 216         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 217
 218         if (sta->fail_avg >= 100)
 219                 return MAX_METRIC;
 220
 221         if (sta->last_tx_rate.flags & IEEE80211_TX_RC_MCS)
 222                 return MAX_METRIC;
 223
 224         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 225
 226         /* bitrate is in units of 100 Kbps, while we need rate in units of
 227          * 1Mbps. This will be corrected on tx_time computation.
 228          */
 229         rate = sband->bitrates[sta->last_tx_rate.idx].bitrate;
 230         tx_time = (device_constant + 10 * test_frame_len / rate);
 231         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 232         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 233         return (u32)result;
 234 }
 235
 236 /**
 237  * hwmp_route_info_get - Update routing info to originator and transmitter
 238  *
 239  * @sdata: local mesh subif
 240  * @mgmt: mesh management frame
 241  * @hwmp_ie: hwmp information element (PREP or PREQ)
 242  *
 243  * This function updates the path routing information to the originator and the
 244  * transmitter of a HWMP PREQ or PREP fram.
 245  *
 246  * Returns: metric to frame originator or 0 if the frame should not be further
 247  * processed
 248  *
 249  * Notes: this function is the only place (besides user-provided info) where
 250  * path routing information is updated.
 251  */
 252 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 253                             struct ieee80211_mgmt *mgmt,
 254                             u8 *hwmp_ie)
 255 {
 256         struct ieee80211_local *local = sdata->local;
 257         struct mesh_path *mpath;
 258         struct sta_info *sta;
 259         bool fresh_info;
 260         u8 *orig_addr, *ta;
 261         u32 orig_dsn, orig_metric;
 262         unsigned long orig_lifetime, exp_time;
 263         u32 last_hop_metric, new_metric;
 264         bool process = true;
 265         u8 action = mgmt->u.action.u.mesh_action.action_code;
 266
 267         rcu_read_lock();
 268         sta = sta_info_get(local, mgmt->sa);
 269         if (!sta) {
 270                 rcu_read_unlock();
 271                 return 0;
 272         }
 273
 274         last_hop_metric = airtime_link_metric_get(local, sta);
 275         /* Update and check originator routing info */
 276         fresh_info = true;
 277
 278         switch (action) {
 279         case MPATH_PREQ:
 280                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 281                 orig_dsn = PREQ_IE_ORIG_DSN(hwmp_ie);
 282                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 283                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 284                 break;
 285         case MPATH_PREP:
 286                 /* Originator here refers to the MP that was the destination in
 287                  * the Path Request. The draft refers to that MP as the
 288                  * destination address, even though usually it is the origin of
 289                  * the PREP frame. We divert from the nomenclature in the draft
 290                  * so that we can easily use a single function to gather path
 291                  * information from both PREQ and PREP frames.
 292                  */
 293                 orig_addr = PREP_IE_ORIG_ADDR(hwmp_ie);
 294                 orig_dsn = PREP_IE_ORIG_DSN(hwmp_ie);
 295                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 296                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 297                 break;
 298         default:
 299                 rcu_read_unlock();
 300                 return 0;
 301         }
 302         new_metric = orig_metric + last_hop_metric;
 303         if (new_metric < orig_metric)
 304                 new_metric = MAX_METRIC;
 305         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 306
 307         if (memcmp(orig_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
 308                 /* This MP is the originator, we are not interested in this
 309                  * frame, except for updating transmitter's path info.
 310                  */
 311                 process = false;
 312                 fresh_info = false;
 313         } else {
 314                 mpath = mesh_path_lookup(orig_addr, sdata);
 315                 if (mpath) {
 316                         spin_lock_bh(&mpath->state_lock);
 317                         if (mpath->flags & MESH_PATH_FIXED)
 318                                 fresh_info = false;
 319                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 320                             (mpath->flags & MESH_PATH_DSN_VALID)) {
 321                                 if (DSN_GT(mpath->dsn, orig_dsn) ||
 322                                     (mpath->dsn == orig_dsn &&
 323                                      action == MPATH_PREQ &&
 324                                      new_metric > mpath->metric)) {
 325                                         process = false;
 326                                         fresh_info = false;
 327                                 }
 328                         }
 329                 } else {
 330                         mesh_path_add(orig_addr, sdata);
 331                         mpath = mesh_path_lookup(orig_addr, sdata);
 332                         if (!mpath) {
 333                                 rcu_read_unlock();
 334                                 return 0;
 335                         }
 336                         spin_lock_bh(&mpath->state_lock);
 337                 }
 338
 339                 if (fresh_info) {
 340                         mesh_path_assign_nexthop(mpath, sta);
 341                         mpath->flags |= MESH_PATH_DSN_VALID;
 342                         mpath->metric = new_metric;
 343                         mpath->dsn = orig_dsn;
 344                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 345                                           ?  mpath->exp_time : exp_time;
 346                         mesh_path_activate(mpath);
 347                         spin_unlock_bh(&mpath->state_lock);
 348                         mesh_path_tx_pending(mpath);
 349                         /* draft says preq_id should be saved to, but there does
 350                          * not seem to be any use for it, skipping by now
 351                          */
 352                 } else
 353                         spin_unlock_bh(&mpath->state_lock);
 354         }
 355
 356         /* Update and check transmitter routing info */
 357         ta = mgmt->sa;
 358         if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
 359                 fresh_info = false;
 360         else {
 361                 fresh_info = true;
 362
 363                 mpath = mesh_path_lookup(ta, sdata);
 364                 if (mpath) {
 365                         spin_lock_bh(&mpath->state_lock);
 366                         if ((mpath->flags & MESH_PATH_FIXED) ||
 367                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 368                                         (last_hop_metric > mpath->metric)))
 369                                 fresh_info = false;
 370                 } else {
 371                         mesh_path_add(ta, sdata);
 372                         mpath = mesh_path_lookup(ta, sdata);
 373                         if (!mpath) {
 374                                 rcu_read_unlock();
 375                                 return 0;
 376                         }
 377                         spin_lock_bh(&mpath->state_lock);
 378                 }
 379
 380                 if (fresh_info) {
 381                         mesh_path_assign_nexthop(mpath, sta);
 382                         mpath->flags &= ~MESH_PATH_DSN_VALID;
 383                         mpath->metric = last_hop_metric;
 384                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 385                                           ?  mpath->exp_time : exp_time;
 386                         mesh_path_activate(mpath);
 387                         spin_unlock_bh(&mpath->state_lock);
 388                         mesh_path_tx_pending(mpath);
 389                 } else
 390                         spin_unlock_bh(&mpath->state_lock);
 391         }
 392
 393         rcu_read_unlock();
 394
 395         return process ? new_metric : 0;
 396 }
 397
 398 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 399                                     struct ieee80211_mgmt *mgmt,
 400                                     u8 *preq_elem, u32 metric) {
 401         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 402         struct mesh_path *mpath;
 403         u8 *dst_addr, *orig_addr;
 404         u8 dst_flags, ttl;
 405         u32 orig_dsn, dst_dsn, lifetime;
 406         bool reply = false;
 407         bool forward = true;
 408
 409         /* Update destination DSN, if present */
 410         dst_addr = PREQ_IE_DST_ADDR(preq_elem);
 411         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 412         dst_dsn = PREQ_IE_DST_DSN(preq_elem);
 413         orig_dsn = PREQ_IE_ORIG_DSN(preq_elem);
 414         dst_flags = PREQ_IE_DST_F(preq_elem);
 415
 416         if (memcmp(dst_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
 417                 forward = false;
 418                 reply = true;
 419                 metric = 0;
 420                 if (time_after(jiffies, ifmsh->last_dsn_update +
 421                                         net_traversal_jiffies(sdata)) ||
 422                     time_before(jiffies, ifmsh->last_dsn_update)) {
 423                         dst_dsn = ++ifmsh->dsn;
 424                         ifmsh->last_dsn_update = jiffies;
 425                 }
 426         } else {
 427                 rcu_read_lock();
 428                 mpath = mesh_path_lookup(dst_addr, sdata);
 429                 if (mpath) {
 430                         if ((!(mpath->flags & MESH_PATH_DSN_VALID)) ||
 431                                         DSN_LT(mpath->dsn, dst_dsn)) {
 432                                 mpath->dsn = dst_dsn;
 433                                 mpath->flags &= MESH_PATH_DSN_VALID;
 434                         } else if ((!(dst_flags & MP_F_DO)) &&
 435                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 436                                 reply = true;
 437                                 metric = mpath->metric;
 438                                 dst_dsn = mpath->dsn;
 439                                 if (dst_flags & MP_F_RF)
 440                                         dst_flags |= MP_F_DO;
 441                                 else
 442                                         forward = false;
 443                         }
 444                 }
 445                 rcu_read_unlock();
 446         }
 447
 448         if (reply) {
 449                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 450                 ttl = ifmsh->mshcfg.dot11MeshTTL;
 451                 if (ttl != 0)
 452                         mesh_path_sel_frame_tx(MPATH_PREP, 0, dst_addr,
 453                                 cpu_to_le32(dst_dsn), 0, orig_addr,
 454                                 cpu_to_le32(orig_dsn), mgmt->sa, 0, ttl,
 455                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 456                                 0, sdata);
 457                 else
 458                         ifmsh->mshstats.dropped_frames_ttl++;
 459         }
 460
 461         if (forward) {
 462                 u32 preq_id;
 463                 u8 hopcount, flags;
 464
 465                 ttl = PREQ_IE_TTL(preq_elem);
 466                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 467                 if (ttl <= 1) {
 468                         ifmsh->mshstats.dropped_frames_ttl++;
 469                         return;
 470                 }
 471                 --ttl;
 472                 flags = PREQ_IE_FLAGS(preq_elem);
 473                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 474                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 475                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 476                                 cpu_to_le32(orig_dsn), dst_flags, dst_addr,
 477                                 cpu_to_le32(dst_dsn), sdata->dev->broadcast,
 478                                 hopcount, ttl, cpu_to_le32(lifetime),
 479                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 480                                 sdata);
 481                 ifmsh->mshstats.fwded_frames++;
 482         }
 483 }
 484
 485
 486 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 487                                     struct ieee80211_mgmt *mgmt,
 488                                     u8 *prep_elem, u32 metric)
 489 {
 490         struct mesh_path *mpath;
 491         u8 *dst_addr, *orig_addr;
 492         u8 ttl, hopcount, flags;
 493         u8 next_hop[ETH_ALEN];
 494         u32 dst_dsn, orig_dsn, lifetime;
 495
 496         /* Note that we divert from the draft nomenclature and denominate
 497          * destination to what the draft refers to as origininator. So in this
 498          * function destnation refers to the final destination of the PREP,
 499          * which corresponds with the originator of the PREQ which this PREP
 500          * replies
 501          */
 502         dst_addr = PREP_IE_DST_ADDR(prep_elem);
 503         if (memcmp(dst_addr, sdata->dev->dev_addr, ETH_ALEN) == 0)
 504                 /* destination, no forwarding required */
 505                 return;
 506
 507         ttl = PREP_IE_TTL(prep_elem);
 508         if (ttl <= 1) {
 509                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 510                 return;
 511         }
 512
 513         rcu_read_lock();
 514         mpath = mesh_path_lookup(dst_addr, sdata);
 515         if (mpath)
 516                 spin_lock_bh(&mpath->state_lock);
 517         else
 518                 goto fail;
 519         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 520                 spin_unlock_bh(&mpath->state_lock);
 521                 goto fail;
 522         }
 523         memcpy(next_hop, mpath->next_hop->sta.addr, ETH_ALEN);
 524         spin_unlock_bh(&mpath->state_lock);
 525         --ttl;
 526         flags = PREP_IE_FLAGS(prep_elem);
 527         lifetime = PREP_IE_LIFETIME(prep_elem);
 528         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 529         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 530         dst_dsn = PREP_IE_DST_DSN(prep_elem);
 531         orig_dsn = PREP_IE_ORIG_DSN(prep_elem);
 532
 533         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 534                 cpu_to_le32(orig_dsn), 0, dst_addr,
 535                 cpu_to_le32(dst_dsn), mpath->next_hop->sta.addr, hopcount, ttl,
 536                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 537                 0, sdata);
 538         rcu_read_unlock();
 539         sdata->u.mesh.mshstats.fwded_frames++;
 540         return;
 541
 542 fail:
 543         rcu_read_unlock();
 544         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 545         return;
 546 }
 547
 548 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 549                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 550 {
 551         struct mesh_path *mpath;
 552         u8 *ta, *dst_addr;
 553         u32 dst_dsn;
 554
 555         ta = mgmt->sa;
 556         dst_addr = PERR_IE_DST_ADDR(perr_elem);
 557         dst_dsn = PERR_IE_DST_DSN(perr_elem);
 558         rcu_read_lock();
 559         mpath = mesh_path_lookup(dst_addr, sdata);
 560         if (mpath) {
 561                 spin_lock_bh(&mpath->state_lock);
 562                 if (mpath->flags & MESH_PATH_ACTIVE &&
 563                     memcmp(ta, mpath->next_hop->sta.addr, ETH_ALEN) == 0 &&
 564                     (!(mpath->flags & MESH_PATH_DSN_VALID) ||
 565                     DSN_GT(dst_dsn, mpath->dsn))) {
 566                         mpath->flags &= ~MESH_PATH_ACTIVE;
 567                         mpath->dsn = dst_dsn;
 568                         spin_unlock_bh(&mpath->state_lock);
 569                         mesh_path_error_tx(dst_addr, cpu_to_le32(dst_dsn),
 570                                            sdata->dev->broadcast, sdata);
 571                 } else
 572                         spin_unlock_bh(&mpath->state_lock);
 573         }
 574         rcu_read_unlock();
 575 }
 576
 577
 578
 579 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 580                             struct ieee80211_mgmt *mgmt,
 581                             size_t len)
 582 {
 583         struct ieee802_11_elems elems;
 584         size_t baselen;
 585         u32 last_hop_metric;
 586
 587         /* need action_code */
 588         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 589                 return;
 590
 591         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 592         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 593                         len - baselen, &elems);
 594
 595         switch (mgmt->u.action.u.mesh_action.action_code) {
 596         case MPATH_PREQ:
 597                 if (!elems.preq || elems.preq_len != 37)
 598                         /* Right now we support just 1 destination and no AE */
 599                         return;
 600                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq);
 601                 if (!last_hop_metric)
 602                         return;
 603                 hwmp_preq_frame_process(sdata, mgmt, elems.preq, last_hop_metric);
 604                 break;
 605         case MPATH_PREP:
 606                 if (!elems.prep || elems.prep_len != 31)
 607                         /* Right now we support no AE */
 608                         return;
 609                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep);
 610                 if (!last_hop_metric)
 611                         return;
 612                 hwmp_prep_frame_process(sdata, mgmt, elems.prep, last_hop_metric);
 613                 break;
 614         case MPATH_PERR:
 615                 if (!elems.perr || elems.perr_len != 12)
 616                         /* Right now we support only one destination per PERR */
 617                         return;
 618                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 619         default:
 620                 return;
 621         }
 622
 623 }
 624
 625 /**
 626  * mesh_queue_preq - queue a PREQ to a given destination
 627  *
 628  * @mpath: mesh path to discover
 629  * @flags: special attributes of the PREQ to be sent
 630  *
 631  * Locking: the function must be called from within a rcu read lock block.
 632  *
 633  */
 634 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 635 {
 636         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 637         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 638         struct mesh_preq_queue *preq_node;
 639
 640         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_KERNEL);
 641         if (!preq_node) {
 642                 printk(KERN_DEBUG "Mesh HWMP: could not allocate PREQ node\n");
 643                 return;
 644         }
 645
 646         spin_lock(&ifmsh->mesh_preq_queue_lock);
 647         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 648                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
 649                 kfree(preq_node);
 650                 if (printk_ratelimit())
 651                         printk(KERN_DEBUG "Mesh HWMP: PREQ node queue full\n");
 652                 return;
 653         }
 654
 655         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 656         preq_node->flags = flags;
 657
 658         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 659         ++ifmsh->preq_queue_len;
 660         spin_unlock(&ifmsh->mesh_preq_queue_lock);
 661
 662         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 663                 queue_work(sdata->local->hw.workqueue, &ifmsh->work);
 664
 665         else if (time_before(jiffies, ifmsh->last_preq)) {
 666                 /* avoid long wait if did not send preqs for a long time
 667                  * and jiffies wrapped around
 668                  */
 669                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 670                 queue_work(sdata->local->hw.workqueue, &ifmsh->work);
 671         } else
 672                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 673                                                 min_preq_int_jiff(sdata));
 674 }
 675
 676 /**
 677  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 678  *
 679  * @sdata: local mesh subif
 680  */
 681 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 682 {
 683         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 684         struct mesh_preq_queue *preq_node;
 685         struct mesh_path *mpath;
 686         u8 ttl, dst_flags;
 687         u32 lifetime;
 688
 689         spin_lock(&ifmsh->mesh_preq_queue_lock);
 690         if (!ifmsh->preq_queue_len ||
 691                 time_before(jiffies, ifmsh->last_preq +
 692                                 min_preq_int_jiff(sdata))) {
 693                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
 694                 return;
 695         }
 696
 697         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 698                         struct mesh_preq_queue, list);
 699         list_del(&preq_node->list);
 700         --ifmsh->preq_queue_len;
 701         spin_unlock(&ifmsh->mesh_preq_queue_lock);
 702
 703         rcu_read_lock();
 704         mpath = mesh_path_lookup(preq_node->dst, sdata);
 705         if (!mpath)
 706                 goto enddiscovery;
 707
 708         spin_lock_bh(&mpath->state_lock);
 709         if (preq_node->flags & PREQ_Q_F_START) {
 710                 if (mpath->flags & MESH_PATH_RESOLVING) {
 711                         spin_unlock_bh(&mpath->state_lock);
 712                         goto enddiscovery;
 713                 } else {
 714                         mpath->flags &= ~MESH_PATH_RESOLVED;
 715                         mpath->flags |= MESH_PATH_RESOLVING;
 716                         mpath->discovery_retries = 0;
 717                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 718                 }
 719         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 720                         mpath->flags & MESH_PATH_RESOLVED) {
 721                 mpath->flags &= ~MESH_PATH_RESOLVING;
 722                 spin_unlock_bh(&mpath->state_lock);
 723                 goto enddiscovery;
 724         }
 725
 726         ifmsh->last_preq = jiffies;
 727
 728         if (time_after(jiffies, ifmsh->last_dsn_update +
 729                                 net_traversal_jiffies(sdata)) ||
 730             time_before(jiffies, ifmsh->last_dsn_update)) {
 731                 ++ifmsh->dsn;
 732                 sdata->u.mesh.last_dsn_update = jiffies;
 733         }
 734         lifetime = default_lifetime(sdata);
 735         ttl = sdata->u.mesh.mshcfg.dot11MeshTTL;
 736         if (ttl == 0) {
 737                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 738                 spin_unlock_bh(&mpath->state_lock);
 739                 goto enddiscovery;
 740         }
 741
 742         if (preq_node->flags & PREQ_Q_F_REFRESH)
 743                 dst_flags = MP_F_DO;
 744         else
 745                 dst_flags = MP_F_RF;
 746
 747         spin_unlock_bh(&mpath->state_lock);
 748         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->dev->dev_addr,
 749                         cpu_to_le32(ifmsh->dsn), dst_flags, mpath->dst,
 750                         cpu_to_le32(mpath->dsn), sdata->dev->broadcast, 0,
 751                         ttl, cpu_to_le32(lifetime), 0,
 752                         cpu_to_le32(ifmsh->preq_id++), sdata);
 753         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 754
 755 enddiscovery:
 756         rcu_read_unlock();
 757         kfree(preq_node);
 758 }
 759
 760 /**
 761  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
 762  *
 763  * @skb: 802.11 frame to be sent
 764  * @sdata: network subif the frame will be sent through
 765  *
 766  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 767  * found, the function will start a path discovery and queue the frame so it is
 768  * sent when the path is resolved. This means the caller must not free the skb
 769  * in this case.
 770  */
 771 int mesh_nexthop_lookup(struct sk_buff *skb,
 772                         struct ieee80211_sub_if_data *sdata)
 773 {
 774         struct sk_buff *skb_to_free = NULL;
 775         struct mesh_path *mpath;
 776         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 777         u8 *dst_addr = hdr->addr3;
 778         int err = 0;
 779
 780         rcu_read_lock();
 781         mpath = mesh_path_lookup(dst_addr, sdata);
 782
 783         if (!mpath) {
 784                 mesh_path_add(dst_addr, sdata);
 785                 mpath = mesh_path_lookup(dst_addr, sdata);
 786                 if (!mpath) {
 787                         dev_kfree_skb(skb);
 788                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 789                         err = -ENOSPC;
 790                         goto endlookup;
 791                 }
 792         }
 793
 794         if (mpath->flags & MESH_PATH_ACTIVE) {
 795                 if (time_after(jiffies, mpath->exp_time -
 796                         msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time))
 797                                 && !memcmp(sdata->dev->dev_addr, hdr->addr4,
 798                                            ETH_ALEN)
 799                                 && !(mpath->flags & MESH_PATH_RESOLVING)
 800                                 && !(mpath->flags & MESH_PATH_FIXED)) {
 801                         mesh_queue_preq(mpath,
 802                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 803                 }
 804                 memcpy(hdr->addr1, mpath->next_hop->sta.addr,
 805                                 ETH_ALEN);
 806         } else {
 807                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
 808                         /* Start discovery only if it is not running yet */
 809                         mesh_queue_preq(mpath, PREQ_Q_F_START);
 810                 }
 811
 812                 if (skb_queue_len(&mpath->frame_queue) >=
 813                                 MESH_FRAME_QUEUE_LEN) {
 814                         skb_to_free = mpath->frame_queue.next;
 815                         skb_unlink(skb_to_free, &mpath->frame_queue);
 816                 }
 817
 818                 skb_queue_tail(&mpath->frame_queue, skb);
 819                 if (skb_to_free)
 820                         mesh_path_discard_frame(skb_to_free, sdata);
 821                 err = -ENOENT;
 822         }
 823
 824 endlookup:
 825         rcu_read_unlock();
 826         return err;
 827 }
 828
 829 void mesh_path_timer(unsigned long data)
 830 {
 831         struct ieee80211_sub_if_data *sdata;
 832         struct mesh_path *mpath;
 833
 834         rcu_read_lock();
 835         mpath = (struct mesh_path *) data;
 836         mpath = rcu_dereference(mpath);
 837         if (!mpath)
 838                 goto endmpathtimer;
 839         spin_lock_bh(&mpath->state_lock);
 840         sdata = mpath->sdata;
 841         if (mpath->flags & MESH_PATH_RESOLVED ||
 842                         (!(mpath->flags & MESH_PATH_RESOLVING)))
 843                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
 844         else if (mpath->discovery_retries < max_preq_retries(sdata)) {
 845                 ++mpath->discovery_retries;
 846                 mpath->discovery_timeout *= 2;
 847                 mesh_queue_preq(mpath, 0);
 848         } else {
 849                 mpath->flags = 0;
 850                 mpath->exp_time = jiffies;
 851                 mesh_path_flush_pending(mpath);
 852         }
 853
 854         spin_unlock_bh(&mpath->state_lock);
 855 endmpathtimer:
 856         rcu_read_unlock();
 857 }