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, 0);
 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, 0);
 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         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 222
 223         /* bitrate is in units of 100 Kbps, while we need rate in units of
 224          * 1Mbps. This will be corrected on tx_time computation.
 225          */
 226         rate = sband->bitrates[sta->last_txrate_idx].bitrate;
 227         tx_time = (device_constant + 10 * test_frame_len / rate);
 228         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 229         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 230         return (u32)result;
 231 }
 232
 233 /**
 234  * hwmp_route_info_get - Update routing info to originator and transmitter
 235  *
 236  * @sdata: local mesh subif
 237  * @mgmt: mesh management frame
 238  * @hwmp_ie: hwmp information element (PREP or PREQ)
 239  *
 240  * This function updates the path routing information to the originator and the
 241  * transmitter of a HWMP PREQ or PREP fram.
 242  *
 243  * Returns: metric to frame originator or 0 if the frame should not be further
 244  * processed
 245  *
 246  * Notes: this function is the only place (besides user-provided info) where
 247  * path routing information is updated.
 248  */
 249 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 250                             struct ieee80211_mgmt *mgmt,
 251                             u8 *hwmp_ie)
 252 {
 253         struct ieee80211_local *local = sdata->local;
 254         struct mesh_path *mpath;
 255         struct sta_info *sta;
 256         bool fresh_info;
 257         u8 *orig_addr, *ta;
 258         u32 orig_dsn, orig_metric;
 259         unsigned long orig_lifetime, exp_time;
 260         u32 last_hop_metric, new_metric;
 261         bool process = true;
 262         u8 action = mgmt->u.action.u.mesh_action.action_code;
 263
 264         rcu_read_lock();
 265         sta = sta_info_get(local, mgmt->sa);
 266         if (!sta) {
 267                 rcu_read_unlock();
 268                 return 0;
 269         }
 270
 271         last_hop_metric = airtime_link_metric_get(local, sta);
 272         /* Update and check originator routing info */
 273         fresh_info = true;
 274
 275         switch (action) {
 276         case MPATH_PREQ:
 277                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 278                 orig_dsn = PREQ_IE_ORIG_DSN(hwmp_ie);
 279                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 280                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 281                 break;
 282         case MPATH_PREP:
 283                 /* Originator here refers to the MP that was the destination in
 284                  * the Path Request. The draft refers to that MP as the
 285                  * destination address, even though usually it is the origin of
 286                  * the PREP frame. We divert from the nomenclature in the draft
 287                  * so that we can easily use a single function to gather path
 288                  * information from both PREQ and PREP frames.
 289                  */
 290                 orig_addr = PREP_IE_ORIG_ADDR(hwmp_ie);
 291                 orig_dsn = PREP_IE_ORIG_DSN(hwmp_ie);
 292                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 293                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 294                 break;
 295         default:
 296                 rcu_read_unlock();
 297                 return 0;
 298         }
 299         new_metric = orig_metric + last_hop_metric;
 300         if (new_metric < orig_metric)
 301                 new_metric = MAX_METRIC;
 302         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 303
 304         if (memcmp(orig_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
 305                 /* This MP is the originator, we are not interested in this
 306                  * frame, except for updating transmitter's path info.
 307                  */
 308                 process = false;
 309                 fresh_info = false;
 310         } else {
 311                 mpath = mesh_path_lookup(orig_addr, sdata);
 312                 if (mpath) {
 313                         spin_lock_bh(&mpath->state_lock);
 314                         if (mpath->flags & MESH_PATH_FIXED)
 315                                 fresh_info = false;
 316                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 317                             (mpath->flags & MESH_PATH_DSN_VALID)) {
 318                                 if (DSN_GT(mpath->dsn, orig_dsn) ||
 319                                     (mpath->dsn == orig_dsn &&
 320                                      action == MPATH_PREQ &&
 321                                      new_metric > mpath->metric)) {
 322                                         process = false;
 323                                         fresh_info = false;
 324                                 }
 325                         }
 326                 } else {
 327                         mesh_path_add(orig_addr, sdata);
 328                         mpath = mesh_path_lookup(orig_addr, sdata);
 329                         if (!mpath) {
 330                                 rcu_read_unlock();
 331                                 return 0;
 332                         }
 333                         spin_lock_bh(&mpath->state_lock);
 334                 }
 335
 336                 if (fresh_info) {
 337                         mesh_path_assign_nexthop(mpath, sta);
 338                         mpath->flags |= MESH_PATH_DSN_VALID;
 339                         mpath->metric = new_metric;
 340                         mpath->dsn = orig_dsn;
 341                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 342                                           ?  mpath->exp_time : exp_time;
 343                         mesh_path_activate(mpath);
 344                         spin_unlock_bh(&mpath->state_lock);
 345                         mesh_path_tx_pending(mpath);
 346                         /* draft says preq_id should be saved to, but there does
 347                          * not seem to be any use for it, skipping by now
 348                          */
 349                 } else
 350                         spin_unlock_bh(&mpath->state_lock);
 351         }
 352
 353         /* Update and check transmitter routing info */
 354         ta = mgmt->sa;
 355         if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
 356                 fresh_info = false;
 357         else {
 358                 fresh_info = true;
 359
 360                 mpath = mesh_path_lookup(ta, sdata);
 361                 if (mpath) {
 362                         spin_lock_bh(&mpath->state_lock);
 363                         if ((mpath->flags & MESH_PATH_FIXED) ||
 364                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 365                                         (last_hop_metric > mpath->metric)))
 366                                 fresh_info = false;
 367                 } else {
 368                         mesh_path_add(ta, sdata);
 369                         mpath = mesh_path_lookup(ta, sdata);
 370                         if (!mpath) {
 371                                 rcu_read_unlock();
 372                                 return 0;
 373                         }
 374                         spin_lock_bh(&mpath->state_lock);
 375                 }
 376
 377                 if (fresh_info) {
 378                         mesh_path_assign_nexthop(mpath, sta);
 379                         mpath->flags &= ~MESH_PATH_DSN_VALID;
 380                         mpath->metric = last_hop_metric;
 381                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 382                                           ?  mpath->exp_time : exp_time;
 383                         mesh_path_activate(mpath);
 384                         spin_unlock_bh(&mpath->state_lock);
 385                         mesh_path_tx_pending(mpath);
 386                 } else
 387                         spin_unlock_bh(&mpath->state_lock);
 388         }
 389
 390         rcu_read_unlock();
 391
 392         return process ? new_metric : 0;
 393 }
 394
 395 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 396                                     struct ieee80211_mgmt *mgmt,
 397                                     u8 *preq_elem, u32 metric) {
 398         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 399         struct mesh_path *mpath;
 400         u8 *dst_addr, *orig_addr;
 401         u8 dst_flags, ttl;
 402         u32 orig_dsn, dst_dsn, lifetime;
 403         bool reply = false;
 404         bool forward = true;
 405
 406         /* Update destination DSN, if present */
 407         dst_addr = PREQ_IE_DST_ADDR(preq_elem);
 408         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 409         dst_dsn = PREQ_IE_DST_DSN(preq_elem);
 410         orig_dsn = PREQ_IE_ORIG_DSN(preq_elem);
 411         dst_flags = PREQ_IE_DST_F(preq_elem);
 412
 413         if (memcmp(dst_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
 414                 forward = false;
 415                 reply = true;
 416                 metric = 0;
 417                 if (time_after(jiffies, ifmsh->last_dsn_update +
 418                                         net_traversal_jiffies(sdata)) ||
 419                     time_before(jiffies, ifmsh->last_dsn_update)) {
 420                         dst_dsn = ++ifmsh->dsn;
 421                         ifmsh->last_dsn_update = jiffies;
 422                 }
 423         } else {
 424                 rcu_read_lock();
 425                 mpath = mesh_path_lookup(dst_addr, sdata);
 426                 if (mpath) {
 427                         if ((!(mpath->flags & MESH_PATH_DSN_VALID)) ||
 428                                         DSN_LT(mpath->dsn, dst_dsn)) {
 429                                 mpath->dsn = dst_dsn;
 430                                 mpath->flags &= MESH_PATH_DSN_VALID;
 431                         } else if ((!(dst_flags & MP_F_DO)) &&
 432                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 433                                 reply = true;
 434                                 metric = mpath->metric;
 435                                 dst_dsn = mpath->dsn;
 436                                 if (dst_flags & MP_F_RF)
 437                                         dst_flags |= MP_F_DO;
 438                                 else
 439                                         forward = false;
 440                         }
 441                 }
 442                 rcu_read_unlock();
 443         }
 444
 445         if (reply) {
 446                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 447                 ttl = ifmsh->mshcfg.dot11MeshTTL;
 448                 if (ttl != 0)
 449                         mesh_path_sel_frame_tx(MPATH_PREP, 0, dst_addr,
 450                                 cpu_to_le32(dst_dsn), 0, orig_addr,
 451                                 cpu_to_le32(orig_dsn), mgmt->sa, 0, ttl,
 452                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 453                                 0, sdata);
 454                 else
 455                         ifmsh->mshstats.dropped_frames_ttl++;
 456         }
 457
 458         if (forward) {
 459                 u32 preq_id;
 460                 u8 hopcount, flags;
 461
 462                 ttl = PREQ_IE_TTL(preq_elem);
 463                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 464                 if (ttl <= 1) {
 465                         ifmsh->mshstats.dropped_frames_ttl++;
 466                         return;
 467                 }
 468                 --ttl;
 469                 flags = PREQ_IE_FLAGS(preq_elem);
 470                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 471                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 472                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 473                                 cpu_to_le32(orig_dsn), dst_flags, dst_addr,
 474                                 cpu_to_le32(dst_dsn), sdata->dev->broadcast,
 475                                 hopcount, ttl, cpu_to_le32(lifetime),
 476                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 477                                 sdata);
 478                 ifmsh->mshstats.fwded_frames++;
 479         }
 480 }
 481
 482
 483 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 484                                     struct ieee80211_mgmt *mgmt,
 485                                     u8 *prep_elem, u32 metric)
 486 {
 487         struct mesh_path *mpath;
 488         u8 *dst_addr, *orig_addr;
 489         u8 ttl, hopcount, flags;
 490         u8 next_hop[ETH_ALEN];
 491         u32 dst_dsn, orig_dsn, lifetime;
 492
 493         /* Note that we divert from the draft nomenclature and denominate
 494          * destination to what the draft refers to as origininator. So in this
 495          * function destnation refers to the final destination of the PREP,
 496          * which corresponds with the originator of the PREQ which this PREP
 497          * replies
 498          */
 499         dst_addr = PREP_IE_DST_ADDR(prep_elem);
 500         if (memcmp(dst_addr, sdata->dev->dev_addr, ETH_ALEN) == 0)
 501                 /* destination, no forwarding required */
 502                 return;
 503
 504         ttl = PREP_IE_TTL(prep_elem);
 505         if (ttl <= 1) {
 506                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 507                 return;
 508         }
 509
 510         rcu_read_lock();
 511         mpath = mesh_path_lookup(dst_addr, sdata);
 512         if (mpath)
 513                 spin_lock_bh(&mpath->state_lock);
 514         else
 515                 goto fail;
 516         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 517                 spin_unlock_bh(&mpath->state_lock);
 518                 goto fail;
 519         }
 520         memcpy(next_hop, mpath->next_hop->sta.addr, ETH_ALEN);
 521         spin_unlock_bh(&mpath->state_lock);
 522         --ttl;
 523         flags = PREP_IE_FLAGS(prep_elem);
 524         lifetime = PREP_IE_LIFETIME(prep_elem);
 525         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 526         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 527         dst_dsn = PREP_IE_DST_DSN(prep_elem);
 528         orig_dsn = PREP_IE_ORIG_DSN(prep_elem);
 529
 530         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 531                 cpu_to_le32(orig_dsn), 0, dst_addr,
 532                 cpu_to_le32(dst_dsn), mpath->next_hop->sta.addr, hopcount, ttl,
 533                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 534                 0, sdata);
 535         rcu_read_unlock();
 536         sdata->u.mesh.mshstats.fwded_frames++;
 537         return;
 538
 539 fail:
 540         rcu_read_unlock();
 541         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 542         return;
 543 }
 544
 545 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 546                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 547 {
 548         struct mesh_path *mpath;
 549         u8 *ta, *dst_addr;
 550         u32 dst_dsn;
 551
 552         ta = mgmt->sa;
 553         dst_addr = PERR_IE_DST_ADDR(perr_elem);
 554         dst_dsn = PERR_IE_DST_DSN(perr_elem);
 555         rcu_read_lock();
 556         mpath = mesh_path_lookup(dst_addr, sdata);
 557         if (mpath) {
 558                 spin_lock_bh(&mpath->state_lock);
 559                 if (mpath->flags & MESH_PATH_ACTIVE &&
 560                     memcmp(ta, mpath->next_hop->sta.addr, ETH_ALEN) == 0 &&
 561                     (!(mpath->flags & MESH_PATH_DSN_VALID) ||
 562                     DSN_GT(dst_dsn, mpath->dsn))) {
 563                         mpath->flags &= ~MESH_PATH_ACTIVE;
 564                         mpath->dsn = dst_dsn;
 565                         spin_unlock_bh(&mpath->state_lock);
 566                         mesh_path_error_tx(dst_addr, cpu_to_le32(dst_dsn),
 567                                            sdata->dev->broadcast, sdata);
 568                 } else
 569                         spin_unlock_bh(&mpath->state_lock);
 570         }
 571         rcu_read_unlock();
 572 }
 573
 574
 575
 576 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 577                             struct ieee80211_mgmt *mgmt,
 578                             size_t len)
 579 {
 580         struct ieee802_11_elems elems;
 581         size_t baselen;
 582         u32 last_hop_metric;
 583
 584         /* need action_code */
 585         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 586                 return;
 587
 588         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 589         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 590                         len - baselen, &elems);
 591
 592         switch (mgmt->u.action.u.mesh_action.action_code) {
 593         case MPATH_PREQ:
 594                 if (!elems.preq || elems.preq_len != 37)
 595                         /* Right now we support just 1 destination and no AE */
 596                         return;
 597                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq);
 598                 if (!last_hop_metric)
 599                         return;
 600                 hwmp_preq_frame_process(sdata, mgmt, elems.preq, last_hop_metric);
 601                 break;
 602         case MPATH_PREP:
 603                 if (!elems.prep || elems.prep_len != 31)
 604                         /* Right now we support no AE */
 605                         return;
 606                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep);
 607                 if (!last_hop_metric)
 608                         return;
 609                 hwmp_prep_frame_process(sdata, mgmt, elems.prep, last_hop_metric);
 610                 break;
 611         case MPATH_PERR:
 612                 if (!elems.perr || elems.perr_len != 12)
 613                         /* Right now we support only one destination per PERR */
 614                         return;
 615                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 616         default:
 617                 return;
 618         }
 619
 620 }
 621
 622 /**
 623  * mesh_queue_preq - queue a PREQ to a given destination
 624  *
 625  * @mpath: mesh path to discover
 626  * @flags: special attributes of the PREQ to be sent
 627  *
 628  * Locking: the function must be called from within a rcu read lock block.
 629  *
 630  */
 631 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 632 {
 633         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 634         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 635         struct mesh_preq_queue *preq_node;
 636
 637         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_KERNEL);
 638         if (!preq_node) {
 639                 printk(KERN_DEBUG "Mesh HWMP: could not allocate PREQ node\n");
 640                 return;
 641         }
 642
 643         spin_lock(&ifmsh->mesh_preq_queue_lock);
 644         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 645                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
 646                 kfree(preq_node);
 647                 if (printk_ratelimit())
 648                         printk(KERN_DEBUG "Mesh HWMP: PREQ node queue full\n");
 649                 return;
 650         }
 651
 652         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 653         preq_node->flags = flags;
 654
 655         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 656         ++ifmsh->preq_queue_len;
 657         spin_unlock(&ifmsh->mesh_preq_queue_lock);
 658
 659         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 660                 queue_work(sdata->local->hw.workqueue, &ifmsh->work);
 661
 662         else if (time_before(jiffies, ifmsh->last_preq)) {
 663                 /* avoid long wait if did not send preqs for a long time
 664                  * and jiffies wrapped around
 665                  */
 666                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 667                 queue_work(sdata->local->hw.workqueue, &ifmsh->work);
 668         } else
 669                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 670                                                 min_preq_int_jiff(sdata));
 671 }
 672
 673 /**
 674  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 675  *
 676  * @sdata: local mesh subif
 677  */
 678 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 679 {
 680         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 681         struct mesh_preq_queue *preq_node;
 682         struct mesh_path *mpath;
 683         u8 ttl, dst_flags;
 684         u32 lifetime;
 685
 686         spin_lock(&ifmsh->mesh_preq_queue_lock);
 687         if (!ifmsh->preq_queue_len ||
 688                 time_before(jiffies, ifmsh->last_preq +
 689                                 min_preq_int_jiff(sdata))) {
 690                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
 691                 return;
 692         }
 693
 694         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 695                         struct mesh_preq_queue, list);
 696         list_del(&preq_node->list);
 697         --ifmsh->preq_queue_len;
 698         spin_unlock(&ifmsh->mesh_preq_queue_lock);
 699
 700         rcu_read_lock();
 701         mpath = mesh_path_lookup(preq_node->dst, sdata);
 702         if (!mpath)
 703                 goto enddiscovery;
 704
 705         spin_lock_bh(&mpath->state_lock);
 706         if (preq_node->flags & PREQ_Q_F_START) {
 707                 if (mpath->flags & MESH_PATH_RESOLVING) {
 708                         spin_unlock_bh(&mpath->state_lock);
 709                         goto enddiscovery;
 710                 } else {
 711                         mpath->flags &= ~MESH_PATH_RESOLVED;
 712                         mpath->flags |= MESH_PATH_RESOLVING;
 713                         mpath->discovery_retries = 0;
 714                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 715                 }
 716         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 717                         mpath->flags & MESH_PATH_RESOLVED) {
 718                 mpath->flags &= ~MESH_PATH_RESOLVING;
 719                 spin_unlock_bh(&mpath->state_lock);
 720                 goto enddiscovery;
 721         }
 722
 723         ifmsh->last_preq = jiffies;
 724
 725         if (time_after(jiffies, ifmsh->last_dsn_update +
 726                                 net_traversal_jiffies(sdata)) ||
 727             time_before(jiffies, ifmsh->last_dsn_update)) {
 728                 ++ifmsh->dsn;
 729                 sdata->u.mesh.last_dsn_update = jiffies;
 730         }
 731         lifetime = default_lifetime(sdata);
 732         ttl = sdata->u.mesh.mshcfg.dot11MeshTTL;
 733         if (ttl == 0) {
 734                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 735                 spin_unlock_bh(&mpath->state_lock);
 736                 goto enddiscovery;
 737         }
 738
 739         if (preq_node->flags & PREQ_Q_F_REFRESH)
 740                 dst_flags = MP_F_DO;
 741         else
 742                 dst_flags = MP_F_RF;
 743
 744         spin_unlock_bh(&mpath->state_lock);
 745         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->dev->dev_addr,
 746                         cpu_to_le32(ifmsh->dsn), dst_flags, mpath->dst,
 747                         cpu_to_le32(mpath->dsn), sdata->dev->broadcast, 0,
 748                         ttl, cpu_to_le32(lifetime), 0,
 749                         cpu_to_le32(ifmsh->preq_id++), sdata);
 750         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 751
 752 enddiscovery:
 753         rcu_read_unlock();
 754         kfree(preq_node);
 755 }
 756
 757 /**
 758  * ieee80211s_lookup_nexthop - put the appropriate next hop on a mesh frame
 759  *
 760  * @skb: 802.11 frame to be sent
 761  * @sdata: network subif the frame will be sent through
 762  * @fwd_frame: true if this frame was originally from a different host
 763  *
 764  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 765  * found, the function will start a path discovery and queue the frame so it is
 766  * sent when the path is resolved. This means the caller must not free the skb
 767  * in this case.
 768  */
 769 int mesh_nexthop_lookup(struct sk_buff *skb,
 770                         struct ieee80211_sub_if_data *sdata)
 771 {
 772         struct sk_buff *skb_to_free = NULL;
 773         struct mesh_path *mpath;
 774         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 775         u8 *dst_addr = hdr->addr3;
 776         int err = 0;
 777
 778         rcu_read_lock();
 779         mpath = mesh_path_lookup(dst_addr, sdata);
 780
 781         if (!mpath) {
 782                 mesh_path_add(dst_addr, sdata);
 783                 mpath = mesh_path_lookup(dst_addr, sdata);
 784                 if (!mpath) {
 785                         dev_kfree_skb(skb);
 786                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 787                         err = -ENOSPC;
 788                         goto endlookup;
 789                 }
 790         }
 791
 792         if (mpath->flags & MESH_PATH_ACTIVE) {
 793                 if (time_after(jiffies, mpath->exp_time -
 794                         msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time))
 795                                 && !memcmp(sdata->dev->dev_addr, hdr->addr4,
 796                                            ETH_ALEN)
 797                                 && !(mpath->flags & MESH_PATH_RESOLVING)
 798                                 && !(mpath->flags & MESH_PATH_FIXED)) {
 799                         mesh_queue_preq(mpath,
 800                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 801                 }
 802                 memcpy(hdr->addr1, mpath->next_hop->sta.addr,
 803                                 ETH_ALEN);
 804         } else {
 805                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
 806                         /* Start discovery only if it is not running yet */
 807                         mesh_queue_preq(mpath, PREQ_Q_F_START);
 808                 }
 809
 810                 if (skb_queue_len(&mpath->frame_queue) >=
 811                                 MESH_FRAME_QUEUE_LEN) {
 812                         skb_to_free = mpath->frame_queue.next;
 813                         skb_unlink(skb_to_free, &mpath->frame_queue);
 814                 }
 815
 816                 skb_queue_tail(&mpath->frame_queue, skb);
 817                 if (skb_to_free)
 818                         mesh_path_discard_frame(skb_to_free, sdata);
 819                 err = -ENOENT;
 820         }
 821
 822 endlookup:
 823         rcu_read_unlock();
 824         return err;
 825 }
 826
 827 void mesh_path_timer(unsigned long data)
 828 {
 829         struct ieee80211_sub_if_data *sdata;
 830         struct mesh_path *mpath;
 831
 832         rcu_read_lock();
 833         mpath = (struct mesh_path *) data;
 834         mpath = rcu_dereference(mpath);
 835         if (!mpath)
 836                 goto endmpathtimer;
 837         spin_lock_bh(&mpath->state_lock);
 838         sdata = mpath->sdata;
 839         if (mpath->flags & MESH_PATH_RESOLVED ||
 840                         (!(mpath->flags & MESH_PATH_RESOLVING)))
 841                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
 842         else if (mpath->discovery_retries < max_preq_retries(sdata)) {
 843                 ++mpath->discovery_retries;
 844                 mpath->discovery_timeout *= 2;
 845                 mesh_queue_preq(mpath, 0);
 846         } else {
 847                 mpath->flags = 0;
 848                 mpath->exp_time = jiffies;
 849                 mesh_path_flush_pending(mpath);
 850         }
 851
 852         spin_unlock_bh(&mpath->state_lock);
 853 endmpathtimer:
 854         rcu_read_unlock();
 855 }