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 TU_TO_EXP_TIME(x) (jiffies + msecs_to_jiffies(x * 1024 / 1000))
  62 #define MSEC_TO_TU(x) (x*1000/1024)
  63 #define DSN_GT(x, y) ((long) (y) - (long) (x) < 0)
  64 #define DSN_LT(x, y) ((long) (x) - (long) (y) < 0)
  65
  66 #define net_traversal_jiffies(s) \
  67         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  68 #define default_lifetime(s) \
  69         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  70 #define min_preq_int_jiff(s) \
  71         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  72 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  73 #define disc_timeout_jiff(s) \
  74         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  75
  76 enum mpath_frame_type {
  77         MPATH_PREQ = 0,
  78         MPATH_PREP,
  79         MPATH_PERR
  80 };
  81
  82 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
  83                 u8 *orig_addr, __le32 orig_dsn, u8 dst_flags, u8 *dst,
  84                 __le32 dst_dsn, u8 *da, u8 hop_count, u8 ttl, __le32 lifetime,
  85                 __le32 metric, __le32 preq_id, struct ieee80211_sub_if_data *sdata)
  86 {
  87         struct ieee80211_local *local = sdata->local;
  88         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
  89         struct ieee80211_mgmt *mgmt;
  90         u8 *pos;
  91         int ie_len;
  92
  93         if (!skb)
  94                 return -1;
  95         skb_reserve(skb, local->hw.extra_tx_headroom);
  96         /* 25 is the size of the common mgmt part (24) plus the size of the
  97          * common action part (1)
  98          */
  99         mgmt = (struct ieee80211_mgmt *)
 100                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 101         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 102         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 103                                           IEEE80211_STYPE_ACTION);
 104
 105         memcpy(mgmt->da, da, ETH_ALEN);
 106         memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
 107         /* BSSID is left zeroed, wildcard value */
 108         mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
 109         mgmt->u.action.u.mesh_action.action_code = action;
 110
 111         switch (action) {
 112         case MPATH_PREQ:
 113                 ie_len = 37;
 114                 pos = skb_put(skb, 2 + ie_len);
 115                 *pos++ = WLAN_EID_PREQ;
 116                 break;
 117         case MPATH_PREP:
 118                 ie_len = 31;
 119                 pos = skb_put(skb, 2 + ie_len);
 120                 *pos++ = WLAN_EID_PREP;
 121                 break;
 122         default:
 123                 kfree_skb(skb);
 124                 return -ENOTSUPP;
 125                 break;
 126         }
 127         *pos++ = ie_len;
 128         *pos++ = flags;
 129         *pos++ = hop_count;
 130         *pos++ = ttl;
 131         if (action == MPATH_PREQ) {
 132                 memcpy(pos, &preq_id, 4);
 133                 pos += 4;
 134         }
 135         memcpy(pos, orig_addr, ETH_ALEN);
 136         pos += ETH_ALEN;
 137         memcpy(pos, &orig_dsn, 4);
 138         pos += 4;
 139         memcpy(pos, &lifetime, 4);
 140         pos += 4;
 141         memcpy(pos, &metric, 4);
 142         pos += 4;
 143         if (action == MPATH_PREQ) {
 144                 /* destination count */
 145                 *pos++ = 1;
 146                 *pos++ = dst_flags;
 147         }
 148         memcpy(pos, dst, ETH_ALEN);
 149         pos += ETH_ALEN;
 150         memcpy(pos, &dst_dsn, 4);
 151
 152         ieee80211_tx_skb(sdata, skb, 1);
 153         return 0;
 154 }
 155
 156 /**
 157  * mesh_send_path error - Sends a PERR mesh management frame
 158  *
 159  * @dst: broken destination
 160  * @dst_dsn: dsn of the broken destination
 161  * @ra: node this frame is addressed to
 162  */
 163 int mesh_path_error_tx(u8 *dst, __le32 dst_dsn, u8 *ra,
 164                 struct ieee80211_sub_if_data *sdata)
 165 {
 166         struct ieee80211_local *local = sdata->local;
 167         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
 168         struct ieee80211_mgmt *mgmt;
 169         u8 *pos;
 170         int ie_len;
 171
 172         if (!skb)
 173                 return -1;
 174         skb_reserve(skb, local->hw.extra_tx_headroom);
 175         /* 25 is the size of the common mgmt part (24) plus the size of the
 176          * common action part (1)
 177          */
 178         mgmt = (struct ieee80211_mgmt *)
 179                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 180         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 181         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 182                                           IEEE80211_STYPE_ACTION);
 183
 184         memcpy(mgmt->da, ra, ETH_ALEN);
 185         memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
 186         /* BSSID is left zeroed, wildcard value */
 187         mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
 188         mgmt->u.action.u.mesh_action.action_code = MPATH_PERR;
 189         ie_len = 12;
 190         pos = skb_put(skb, 2 + ie_len);
 191         *pos++ = WLAN_EID_PERR;
 192         *pos++ = ie_len;
 193         /* mode flags, reserved */
 194         *pos++ = 0;
 195         /* number of destinations */
 196         *pos++ = 1;
 197         memcpy(pos, dst, ETH_ALEN);
 198         pos += ETH_ALEN;
 199         memcpy(pos, &dst_dsn, 4);
 200
 201         ieee80211_tx_skb(sdata, skb, 1);
 202         return 0;
 203 }
 204
 205 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 206                                    struct sta_info *sta)
 207 {
 208         struct ieee80211_supported_band *sband;
 209         /* This should be adjusted for each device */
 210         int device_constant = 1 << ARITH_SHIFT;
 211         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 212         int s_unit = 1 << ARITH_SHIFT;
 213         int rate, err;
 214         u32 tx_time, estimated_retx;
 215         u64 result;
 216
 217         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 218
 219         if (sta->fail_avg >= 100)
 220                 return MAX_METRIC;
 221
 222         if (sta->last_tx_rate.flags & IEEE80211_TX_RC_MCS)
 223                 return MAX_METRIC;
 224
 225         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 226
 227         /* bitrate is in units of 100 Kbps, while we need rate in units of
 228          * 1Mbps. This will be corrected on tx_time computation.
 229          */
 230         rate = sband->bitrates[sta->last_tx_rate.idx].bitrate;
 231         tx_time = (device_constant + 10 * test_frame_len / rate);
 232         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 233         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 234         return (u32)result;
 235 }
 236
 237 /**
 238  * hwmp_route_info_get - Update routing info to originator and transmitter
 239  *
 240  * @sdata: local mesh subif
 241  * @mgmt: mesh management frame
 242  * @hwmp_ie: hwmp information element (PREP or PREQ)
 243  *
 244  * This function updates the path routing information to the originator and the
 245  * transmitter of a HWMP PREQ or PREP fram.
 246  *
 247  * Returns: metric to frame originator or 0 if the frame should not be further
 248  * processed
 249  *
 250  * Notes: this function is the only place (besides user-provided info) where
 251  * path routing information is updated.
 252  */
 253 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 254                             struct ieee80211_mgmt *mgmt,
 255                             u8 *hwmp_ie)
 256 {
 257         struct ieee80211_local *local = sdata->local;
 258         struct mesh_path *mpath;
 259         struct sta_info *sta;
 260         bool fresh_info;
 261         u8 *orig_addr, *ta;
 262         u32 orig_dsn, orig_metric;
 263         unsigned long orig_lifetime, exp_time;
 264         u32 last_hop_metric, new_metric;
 265         bool process = true;
 266         u8 action = mgmt->u.action.u.mesh_action.action_code;
 267
 268         rcu_read_lock();
 269         sta = sta_info_get(local, mgmt->sa);
 270         if (!sta) {
 271                 rcu_read_unlock();
 272                 return 0;
 273         }
 274
 275         last_hop_metric = airtime_link_metric_get(local, sta);
 276         /* Update and check originator routing info */
 277         fresh_info = true;
 278
 279         switch (action) {
 280         case MPATH_PREQ:
 281                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 282                 orig_dsn = PREQ_IE_ORIG_DSN(hwmp_ie);
 283                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 284                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 285                 break;
 286         case MPATH_PREP:
 287                 /* Originator here refers to the MP that was the destination in
 288                  * the Path Request. The draft refers to that MP as the
 289                  * destination address, even though usually it is the origin of
 290                  * the PREP frame. We divert from the nomenclature in the draft
 291                  * so that we can easily use a single function to gather path
 292                  * information from both PREQ and PREP frames.
 293                  */
 294                 orig_addr = PREP_IE_ORIG_ADDR(hwmp_ie);
 295                 orig_dsn = PREP_IE_ORIG_DSN(hwmp_ie);
 296                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 297                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 298                 break;
 299         default:
 300                 rcu_read_unlock();
 301                 return 0;
 302         }
 303         new_metric = orig_metric + last_hop_metric;
 304         if (new_metric < orig_metric)
 305                 new_metric = MAX_METRIC;
 306         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 307
 308         if (memcmp(orig_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
 309                 /* This MP is the originator, we are not interested in this
 310                  * frame, except for updating transmitter's path info.
 311                  */
 312                 process = false;
 313                 fresh_info = false;
 314         } else {
 315                 mpath = mesh_path_lookup(orig_addr, sdata);
 316                 if (mpath) {
 317                         spin_lock_bh(&mpath->state_lock);
 318                         if (mpath->flags & MESH_PATH_FIXED)
 319                                 fresh_info = false;
 320                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 321                             (mpath->flags & MESH_PATH_DSN_VALID)) {
 322                                 if (DSN_GT(mpath->dsn, orig_dsn) ||
 323                                     (mpath->dsn == orig_dsn &&
 324                                      action == MPATH_PREQ &&
 325                                      new_metric > mpath->metric)) {
 326                                         process = false;
 327                                         fresh_info = false;
 328                                 }
 329                         }
 330                 } else {
 331                         mesh_path_add(orig_addr, sdata);
 332                         mpath = mesh_path_lookup(orig_addr, sdata);
 333                         if (!mpath) {
 334                                 rcu_read_unlock();
 335                                 return 0;
 336                         }
 337                         spin_lock_bh(&mpath->state_lock);
 338                 }
 339
 340                 if (fresh_info) {
 341                         mesh_path_assign_nexthop(mpath, sta);
 342                         mpath->flags |= MESH_PATH_DSN_VALID;
 343                         mpath->metric = new_metric;
 344                         mpath->dsn = orig_dsn;
 345                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 346                                           ?  mpath->exp_time : exp_time;
 347                         mesh_path_activate(mpath);
 348                         spin_unlock_bh(&mpath->state_lock);
 349                         mesh_path_tx_pending(mpath);
 350                         /* draft says preq_id should be saved to, but there does
 351                          * not seem to be any use for it, skipping by now
 352                          */
 353                 } else
 354                         spin_unlock_bh(&mpath->state_lock);
 355         }
 356
 357         /* Update and check transmitter routing info */
 358         ta = mgmt->sa;
 359         if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
 360                 fresh_info = false;
 361         else {
 362                 fresh_info = true;
 363
 364                 mpath = mesh_path_lookup(ta, sdata);
 365                 if (mpath) {
 366                         spin_lock_bh(&mpath->state_lock);
 367                         if ((mpath->flags & MESH_PATH_FIXED) ||
 368                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 369                                         (last_hop_metric > mpath->metric)))
 370                                 fresh_info = false;
 371                 } else {
 372                         mesh_path_add(ta, sdata);
 373                         mpath = mesh_path_lookup(ta, sdata);
 374                         if (!mpath) {
 375                                 rcu_read_unlock();
 376                                 return 0;
 377                         }
 378                         spin_lock_bh(&mpath->state_lock);
 379                 }
 380
 381                 if (fresh_info) {
 382                         mesh_path_assign_nexthop(mpath, sta);
 383                         mpath->flags &= ~MESH_PATH_DSN_VALID;
 384                         mpath->metric = last_hop_metric;
 385                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 386                                           ?  mpath->exp_time : exp_time;
 387                         mesh_path_activate(mpath);
 388                         spin_unlock_bh(&mpath->state_lock);
 389                         mesh_path_tx_pending(mpath);
 390                 } else
 391                         spin_unlock_bh(&mpath->state_lock);
 392         }
 393
 394         rcu_read_unlock();
 395
 396         return process ? new_metric : 0;
 397 }
 398
 399 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 400                                     struct ieee80211_mgmt *mgmt,
 401                                     u8 *preq_elem, u32 metric) {
 402         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 403         struct mesh_path *mpath;
 404         u8 *dst_addr, *orig_addr;
 405         u8 dst_flags, ttl;
 406         u32 orig_dsn, dst_dsn, lifetime;
 407         bool reply = false;
 408         bool forward = true;
 409
 410         /* Update destination DSN, if present */
 411         dst_addr = PREQ_IE_DST_ADDR(preq_elem);
 412         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 413         dst_dsn = PREQ_IE_DST_DSN(preq_elem);
 414         orig_dsn = PREQ_IE_ORIG_DSN(preq_elem);
 415         dst_flags = PREQ_IE_DST_F(preq_elem);
 416
 417         if (memcmp(dst_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
 418                 forward = false;
 419                 reply = true;
 420                 metric = 0;
 421                 if (time_after(jiffies, ifmsh->last_dsn_update +
 422                                         net_traversal_jiffies(sdata)) ||
 423                     time_before(jiffies, ifmsh->last_dsn_update)) {
 424                         dst_dsn = ++ifmsh->dsn;
 425                         ifmsh->last_dsn_update = jiffies;
 426                 }
 427         } else {
 428                 rcu_read_lock();
 429                 mpath = mesh_path_lookup(dst_addr, sdata);
 430                 if (mpath) {
 431                         if ((!(mpath->flags & MESH_PATH_DSN_VALID)) ||
 432                                         DSN_LT(mpath->dsn, dst_dsn)) {
 433                                 mpath->dsn = dst_dsn;
 434                                 mpath->flags &= MESH_PATH_DSN_VALID;
 435                         } else if ((!(dst_flags & MP_F_DO)) &&
 436                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 437                                 reply = true;
 438                                 metric = mpath->metric;
 439                                 dst_dsn = mpath->dsn;
 440                                 if (dst_flags & MP_F_RF)
 441                                         dst_flags |= MP_F_DO;
 442                                 else
 443                                         forward = false;
 444                         }
 445                 }
 446                 rcu_read_unlock();
 447         }
 448
 449         if (reply) {
 450                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 451                 ttl = ifmsh->mshcfg.dot11MeshTTL;
 452                 if (ttl != 0)
 453                         mesh_path_sel_frame_tx(MPATH_PREP, 0, dst_addr,
 454                                 cpu_to_le32(dst_dsn), 0, orig_addr,
 455                                 cpu_to_le32(orig_dsn), mgmt->sa, 0, ttl,
 456                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 457                                 0, sdata);
 458                 else
 459                         ifmsh->mshstats.dropped_frames_ttl++;
 460         }
 461
 462         if (forward) {
 463                 u32 preq_id;
 464                 u8 hopcount, flags;
 465
 466                 ttl = PREQ_IE_TTL(preq_elem);
 467                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 468                 if (ttl <= 1) {
 469                         ifmsh->mshstats.dropped_frames_ttl++;
 470                         return;
 471                 }
 472                 --ttl;
 473                 flags = PREQ_IE_FLAGS(preq_elem);
 474                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 475                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 476                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 477                                 cpu_to_le32(orig_dsn), dst_flags, dst_addr,
 478                                 cpu_to_le32(dst_dsn), sdata->dev->broadcast,
 479                                 hopcount, ttl, cpu_to_le32(lifetime),
 480                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 481                                 sdata);
 482                 ifmsh->mshstats.fwded_frames++;
 483         }
 484 }
 485
 486
 487 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 488                                     struct ieee80211_mgmt *mgmt,
 489                                     u8 *prep_elem, u32 metric)
 490 {
 491         struct mesh_path *mpath;
 492         u8 *dst_addr, *orig_addr;
 493         u8 ttl, hopcount, flags;
 494         u8 next_hop[ETH_ALEN];
 495         u32 dst_dsn, orig_dsn, lifetime;
 496
 497         /* Note that we divert from the draft nomenclature and denominate
 498          * destination to what the draft refers to as origininator. So in this
 499          * function destnation refers to the final destination of the PREP,
 500          * which corresponds with the originator of the PREQ which this PREP
 501          * replies
 502          */
 503         dst_addr = PREP_IE_DST_ADDR(prep_elem);
 504         if (memcmp(dst_addr, sdata->dev->dev_addr, ETH_ALEN) == 0)
 505                 /* destination, no forwarding required */
 506                 return;
 507
 508         ttl = PREP_IE_TTL(prep_elem);
 509         if (ttl <= 1) {
 510                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 511                 return;
 512         }
 513
 514         rcu_read_lock();
 515         mpath = mesh_path_lookup(dst_addr, sdata);
 516         if (mpath)
 517                 spin_lock_bh(&mpath->state_lock);
 518         else
 519                 goto fail;
 520         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 521                 spin_unlock_bh(&mpath->state_lock);
 522                 goto fail;
 523         }
 524         memcpy(next_hop, mpath->next_hop->sta.addr, ETH_ALEN);
 525         spin_unlock_bh(&mpath->state_lock);
 526         --ttl;
 527         flags = PREP_IE_FLAGS(prep_elem);
 528         lifetime = PREP_IE_LIFETIME(prep_elem);
 529         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 530         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 531         dst_dsn = PREP_IE_DST_DSN(prep_elem);
 532         orig_dsn = PREP_IE_ORIG_DSN(prep_elem);
 533
 534         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 535                 cpu_to_le32(orig_dsn), 0, dst_addr,
 536                 cpu_to_le32(dst_dsn), mpath->next_hop->sta.addr, hopcount, ttl,
 537                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 538                 0, sdata);
 539         rcu_read_unlock();
 540         sdata->u.mesh.mshstats.fwded_frames++;
 541         return;
 542
 543 fail:
 544         rcu_read_unlock();
 545         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 546         return;
 547 }
 548
 549 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 550                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 551 {
 552         struct mesh_path *mpath;
 553         u8 *ta, *dst_addr;
 554         u32 dst_dsn;
 555
 556         ta = mgmt->sa;
 557         dst_addr = PERR_IE_DST_ADDR(perr_elem);
 558         dst_dsn = PERR_IE_DST_DSN(perr_elem);
 559         rcu_read_lock();
 560         mpath = mesh_path_lookup(dst_addr, sdata);
 561         if (mpath) {
 562                 spin_lock_bh(&mpath->state_lock);
 563                 if (mpath->flags & MESH_PATH_ACTIVE &&
 564                     memcmp(ta, mpath->next_hop->sta.addr, ETH_ALEN) == 0 &&
 565                     (!(mpath->flags & MESH_PATH_DSN_VALID) ||
 566                     DSN_GT(dst_dsn, mpath->dsn))) {
 567                         mpath->flags &= ~MESH_PATH_ACTIVE;
 568                         mpath->dsn = dst_dsn;
 569                         spin_unlock_bh(&mpath->state_lock);
 570                         mesh_path_error_tx(dst_addr, cpu_to_le32(dst_dsn),
 571                                            sdata->dev->broadcast, sdata);
 572                 } else
 573                         spin_unlock_bh(&mpath->state_lock);
 574         }
 575         rcu_read_unlock();
 576 }
 577
 578
 579
 580 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 581                             struct ieee80211_mgmt *mgmt,
 582                             size_t len)
 583 {
 584         struct ieee802_11_elems elems;
 585         size_t baselen;
 586         u32 last_hop_metric;
 587
 588         /* need action_code */
 589         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 590                 return;
 591
 592         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 593         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 594                         len - baselen, &elems);
 595
 596         switch (mgmt->u.action.u.mesh_action.action_code) {
 597         case MPATH_PREQ:
 598                 if (!elems.preq || elems.preq_len != 37)
 599                         /* Right now we support just 1 destination and no AE */
 600                         return;
 601                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq);
 602                 if (!last_hop_metric)
 603                         return;
 604                 hwmp_preq_frame_process(sdata, mgmt, elems.preq, last_hop_metric);
 605                 break;
 606         case MPATH_PREP:
 607                 if (!elems.prep || elems.prep_len != 31)
 608                         /* Right now we support no AE */
 609                         return;
 610                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep);
 611                 if (!last_hop_metric)
 612                         return;
 613                 hwmp_prep_frame_process(sdata, mgmt, elems.prep, last_hop_metric);
 614                 break;
 615         case MPATH_PERR:
 616                 if (!elems.perr || elems.perr_len != 12)
 617                         /* Right now we support only one destination per PERR */
 618                         return;
 619                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 620         default:
 621                 return;
 622         }
 623
 624 }
 625
 626 /**
 627  * mesh_queue_preq - queue a PREQ to a given destination
 628  *
 629  * @mpath: mesh path to discover
 630  * @flags: special attributes of the PREQ to be sent
 631  *
 632  * Locking: the function must be called from within a rcu read lock block.
 633  *
 634  */
 635 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 636 {
 637         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 638         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 639         struct mesh_preq_queue *preq_node;
 640
 641         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_KERNEL);
 642         if (!preq_node) {
 643                 printk(KERN_DEBUG "Mesh HWMP: could not allocate PREQ node\n");
 644                 return;
 645         }
 646
 647         spin_lock(&ifmsh->mesh_preq_queue_lock);
 648         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 649                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
 650                 kfree(preq_node);
 651                 if (printk_ratelimit())
 652                         printk(KERN_DEBUG "Mesh HWMP: PREQ node queue full\n");
 653                 return;
 654         }
 655
 656         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 657         preq_node->flags = flags;
 658
 659         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 660         ++ifmsh->preq_queue_len;
 661         spin_unlock(&ifmsh->mesh_preq_queue_lock);
 662
 663         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 664                 queue_work(sdata->local->hw.workqueue, &ifmsh->work);
 665
 666         else if (time_before(jiffies, ifmsh->last_preq)) {
 667                 /* avoid long wait if did not send preqs for a long time
 668                  * and jiffies wrapped around
 669                  */
 670                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 671                 queue_work(sdata->local->hw.workqueue, &ifmsh->work);
 672         } else
 673                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 674                                                 min_preq_int_jiff(sdata));
 675 }
 676
 677 /**
 678  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 679  *
 680  * @sdata: local mesh subif
 681  */
 682 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 683 {
 684         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 685         struct mesh_preq_queue *preq_node;
 686         struct mesh_path *mpath;
 687         u8 ttl, dst_flags;
 688         u32 lifetime;
 689
 690         spin_lock(&ifmsh->mesh_preq_queue_lock);
 691         if (!ifmsh->preq_queue_len ||
 692                 time_before(jiffies, ifmsh->last_preq +
 693                                 min_preq_int_jiff(sdata))) {
 694                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
 695                 return;
 696         }
 697
 698         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 699                         struct mesh_preq_queue, list);
 700         list_del(&preq_node->list);
 701         --ifmsh->preq_queue_len;
 702         spin_unlock(&ifmsh->mesh_preq_queue_lock);
 703
 704         rcu_read_lock();
 705         mpath = mesh_path_lookup(preq_node->dst, sdata);
 706         if (!mpath)
 707                 goto enddiscovery;
 708
 709         spin_lock_bh(&mpath->state_lock);
 710         if (preq_node->flags & PREQ_Q_F_START) {
 711                 if (mpath->flags & MESH_PATH_RESOLVING) {
 712                         spin_unlock_bh(&mpath->state_lock);
 713                         goto enddiscovery;
 714                 } else {
 715                         mpath->flags &= ~MESH_PATH_RESOLVED;
 716                         mpath->flags |= MESH_PATH_RESOLVING;
 717                         mpath->discovery_retries = 0;
 718                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 719                 }
 720         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 721                         mpath->flags & MESH_PATH_RESOLVED) {
 722                 mpath->flags &= ~MESH_PATH_RESOLVING;
 723                 spin_unlock_bh(&mpath->state_lock);
 724                 goto enddiscovery;
 725         }
 726
 727         ifmsh->last_preq = jiffies;
 728
 729         if (time_after(jiffies, ifmsh->last_dsn_update +
 730                                 net_traversal_jiffies(sdata)) ||
 731             time_before(jiffies, ifmsh->last_dsn_update)) {
 732                 ++ifmsh->dsn;
 733                 sdata->u.mesh.last_dsn_update = jiffies;
 734         }
 735         lifetime = default_lifetime(sdata);
 736         ttl = sdata->u.mesh.mshcfg.dot11MeshTTL;
 737         if (ttl == 0) {
 738                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 739                 spin_unlock_bh(&mpath->state_lock);
 740                 goto enddiscovery;
 741         }
 742
 743         if (preq_node->flags & PREQ_Q_F_REFRESH)
 744                 dst_flags = MP_F_DO;
 745         else
 746                 dst_flags = MP_F_RF;
 747
 748         spin_unlock_bh(&mpath->state_lock);
 749         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->dev->dev_addr,
 750                         cpu_to_le32(ifmsh->dsn), dst_flags, mpath->dst,
 751                         cpu_to_le32(mpath->dsn), sdata->dev->broadcast, 0,
 752                         ttl, cpu_to_le32(lifetime), 0,
 753                         cpu_to_le32(ifmsh->preq_id++), sdata);
 754         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 755
 756 enddiscovery:
 757         rcu_read_unlock();
 758         kfree(preq_node);
 759 }
 760
 761 /**
 762  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
 763  *
 764  * @skb: 802.11 frame to be sent
 765  * @sdata: network subif the frame will be sent through
 766  *
 767  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 768  * found, the function will start a path discovery and queue the frame so it is
 769  * sent when the path is resolved. This means the caller must not free the skb
 770  * in this case.
 771  */
 772 int mesh_nexthop_lookup(struct sk_buff *skb,
 773                         struct ieee80211_sub_if_data *sdata)
 774 {
 775         struct sk_buff *skb_to_free = NULL;
 776         struct mesh_path *mpath;
 777         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 778         u8 *dst_addr = hdr->addr3;
 779         int err = 0;
 780
 781         rcu_read_lock();
 782         mpath = mesh_path_lookup(dst_addr, sdata);
 783
 784         if (!mpath) {
 785                 mesh_path_add(dst_addr, sdata);
 786                 mpath = mesh_path_lookup(dst_addr, sdata);
 787                 if (!mpath) {
 788                         dev_kfree_skb(skb);
 789                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 790                         err = -ENOSPC;
 791                         goto endlookup;
 792                 }
 793         }
 794
 795         if (mpath->flags & MESH_PATH_ACTIVE) {
 796                 if (time_after(jiffies, mpath->exp_time -
 797                         msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time))
 798                                 && !memcmp(sdata->dev->dev_addr, hdr->addr4,
 799                                            ETH_ALEN)
 800                                 && !(mpath->flags & MESH_PATH_RESOLVING)
 801                                 && !(mpath->flags & MESH_PATH_FIXED)) {
 802                         mesh_queue_preq(mpath,
 803                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 804                 }
 805                 memcpy(hdr->addr1, mpath->next_hop->sta.addr,
 806                                 ETH_ALEN);
 807         } else {
 808                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
 809                         /* Start discovery only if it is not running yet */
 810                         mesh_queue_preq(mpath, PREQ_Q_F_START);
 811                 }
 812
 813                 if (skb_queue_len(&mpath->frame_queue) >=
 814                                 MESH_FRAME_QUEUE_LEN) {
 815                         skb_to_free = mpath->frame_queue.next;
 816                         skb_unlink(skb_to_free, &mpath->frame_queue);
 817                 }
 818
 819                 skb_queue_tail(&mpath->frame_queue, skb);
 820                 if (skb_to_free)
 821                         mesh_path_discard_frame(skb_to_free, sdata);
 822                 err = -ENOENT;
 823         }
 824
 825 endlookup:
 826         rcu_read_unlock();
 827         return err;
 828 }
 829
 830 void mesh_path_timer(unsigned long data)
 831 {
 832         struct ieee80211_sub_if_data *sdata;
 833         struct mesh_path *mpath;
 834
 835         rcu_read_lock();
 836         mpath = (struct mesh_path *) data;
 837         mpath = rcu_dereference(mpath);
 838         if (!mpath)
 839                 goto endmpathtimer;
 840         spin_lock_bh(&mpath->state_lock);
 841         sdata = mpath->sdata;
 842         if (mpath->flags & MESH_PATH_RESOLVED ||
 843                         (!(mpath->flags & MESH_PATH_RESOLVING)))
 844                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
 845         else if (mpath->discovery_retries < max_preq_retries(sdata)) {
 846                 ++mpath->discovery_retries;
 847                 mpath->discovery_timeout *= 2;
 848                 mesh_queue_preq(mpath, 0);
 849         } else {
 850                 mpath->flags = 0;
 851                 mpath->exp_time = jiffies;
 852                 mesh_path_flush_pending(mpath);
 853         }
 854
 855         spin_unlock_bh(&mpath->state_lock);
 856 endmpathtimer:
 857         rcu_read_unlock();
 858 }