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 void ieee80211s_update_metric(struct ieee80211_local *local,
 205                 struct sta_info *stainfo, struct sk_buff *skb)
 206 {
 207         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 208         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 209         int failed;
 210
 211         if (!ieee80211_is_data(hdr->frame_control))
 212                 return;
 213
 214         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 215
 216         /* moving average, scaled to 100 */
 217         stainfo->fail_avg = ((80 * stainfo->fail_avg + 5) / 100 + 20 * failed);
 218         if (stainfo->fail_avg > 95)
 219                 mesh_plink_broken(stainfo);
 220 }
 221
 222 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 223                                    struct sta_info *sta)
 224 {
 225         struct ieee80211_supported_band *sband;
 226         /* This should be adjusted for each device */
 227         int device_constant = 1 << ARITH_SHIFT;
 228         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 229         int s_unit = 1 << ARITH_SHIFT;
 230         int rate, err;
 231         u32 tx_time, estimated_retx;
 232         u64 result;
 233
 234         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 235
 236         if (sta->fail_avg >= 100)
 237                 return MAX_METRIC;
 238
 239         if (sta->last_tx_rate.flags & IEEE80211_TX_RC_MCS)
 240                 return MAX_METRIC;
 241
 242         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 243
 244         /* bitrate is in units of 100 Kbps, while we need rate in units of
 245          * 1Mbps. This will be corrected on tx_time computation.
 246          */
 247         rate = sband->bitrates[sta->last_tx_rate.idx].bitrate;
 248         tx_time = (device_constant + 10 * test_frame_len / rate);
 249         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 250         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 251         return (u32)result;
 252 }
 253
 254 /**
 255  * hwmp_route_info_get - Update routing info to originator and transmitter
 256  *
 257  * @sdata: local mesh subif
 258  * @mgmt: mesh management frame
 259  * @hwmp_ie: hwmp information element (PREP or PREQ)
 260  *
 261  * This function updates the path routing information to the originator and the
 262  * transmitter of a HWMP PREQ or PREP fram.
 263  *
 264  * Returns: metric to frame originator or 0 if the frame should not be further
 265  * processed
 266  *
 267  * Notes: this function is the only place (besides user-provided info) where
 268  * path routing information is updated.
 269  */
 270 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 271                             struct ieee80211_mgmt *mgmt,
 272                             u8 *hwmp_ie)
 273 {
 274         struct ieee80211_local *local = sdata->local;
 275         struct mesh_path *mpath;
 276         struct sta_info *sta;
 277         bool fresh_info;
 278         u8 *orig_addr, *ta;
 279         u32 orig_dsn, orig_metric;
 280         unsigned long orig_lifetime, exp_time;
 281         u32 last_hop_metric, new_metric;
 282         bool process = true;
 283         u8 action = mgmt->u.action.u.mesh_action.action_code;
 284
 285         rcu_read_lock();
 286         sta = sta_info_get(local, mgmt->sa);
 287         if (!sta) {
 288                 rcu_read_unlock();
 289                 return 0;
 290         }
 291
 292         last_hop_metric = airtime_link_metric_get(local, sta);
 293         /* Update and check originator routing info */
 294         fresh_info = true;
 295
 296         switch (action) {
 297         case MPATH_PREQ:
 298                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 299                 orig_dsn = PREQ_IE_ORIG_DSN(hwmp_ie);
 300                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 301                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 302                 break;
 303         case MPATH_PREP:
 304                 /* Originator here refers to the MP that was the destination in
 305                  * the Path Request. The draft refers to that MP as the
 306                  * destination address, even though usually it is the origin of
 307                  * the PREP frame. We divert from the nomenclature in the draft
 308                  * so that we can easily use a single function to gather path
 309                  * information from both PREQ and PREP frames.
 310                  */
 311                 orig_addr = PREP_IE_ORIG_ADDR(hwmp_ie);
 312                 orig_dsn = PREP_IE_ORIG_DSN(hwmp_ie);
 313                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 314                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 315                 break;
 316         default:
 317                 rcu_read_unlock();
 318                 return 0;
 319         }
 320         new_metric = orig_metric + last_hop_metric;
 321         if (new_metric < orig_metric)
 322                 new_metric = MAX_METRIC;
 323         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 324
 325         if (memcmp(orig_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
 326                 /* This MP is the originator, we are not interested in this
 327                  * frame, except for updating transmitter's path info.
 328                  */
 329                 process = false;
 330                 fresh_info = false;
 331         } else {
 332                 mpath = mesh_path_lookup(orig_addr, sdata);
 333                 if (mpath) {
 334                         spin_lock_bh(&mpath->state_lock);
 335                         if (mpath->flags & MESH_PATH_FIXED)
 336                                 fresh_info = false;
 337                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 338                             (mpath->flags & MESH_PATH_DSN_VALID)) {
 339                                 if (DSN_GT(mpath->dsn, orig_dsn) ||
 340                                     (mpath->dsn == orig_dsn &&
 341                                      action == MPATH_PREQ &&
 342                                      new_metric > mpath->metric)) {
 343                                         process = false;
 344                                         fresh_info = false;
 345                                 }
 346                         }
 347                 } else {
 348                         mesh_path_add(orig_addr, sdata);
 349                         mpath = mesh_path_lookup(orig_addr, sdata);
 350                         if (!mpath) {
 351                                 rcu_read_unlock();
 352                                 return 0;
 353                         }
 354                         spin_lock_bh(&mpath->state_lock);
 355                 }
 356
 357                 if (fresh_info) {
 358                         mesh_path_assign_nexthop(mpath, sta);
 359                         mpath->flags |= MESH_PATH_DSN_VALID;
 360                         mpath->metric = new_metric;
 361                         mpath->dsn = orig_dsn;
 362                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 363                                           ?  mpath->exp_time : exp_time;
 364                         mesh_path_activate(mpath);
 365                         spin_unlock_bh(&mpath->state_lock);
 366                         mesh_path_tx_pending(mpath);
 367                         /* draft says preq_id should be saved to, but there does
 368                          * not seem to be any use for it, skipping by now
 369                          */
 370                 } else
 371                         spin_unlock_bh(&mpath->state_lock);
 372         }
 373
 374         /* Update and check transmitter routing info */
 375         ta = mgmt->sa;
 376         if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
 377                 fresh_info = false;
 378         else {
 379                 fresh_info = true;
 380
 381                 mpath = mesh_path_lookup(ta, sdata);
 382                 if (mpath) {
 383                         spin_lock_bh(&mpath->state_lock);
 384                         if ((mpath->flags & MESH_PATH_FIXED) ||
 385                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 386                                         (last_hop_metric > mpath->metric)))
 387                                 fresh_info = false;
 388                 } else {
 389                         mesh_path_add(ta, sdata);
 390                         mpath = mesh_path_lookup(ta, sdata);
 391                         if (!mpath) {
 392                                 rcu_read_unlock();
 393                                 return 0;
 394                         }
 395                         spin_lock_bh(&mpath->state_lock);
 396                 }
 397
 398                 if (fresh_info) {
 399                         mesh_path_assign_nexthop(mpath, sta);
 400                         mpath->flags &= ~MESH_PATH_DSN_VALID;
 401                         mpath->metric = last_hop_metric;
 402                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 403                                           ?  mpath->exp_time : exp_time;
 404                         mesh_path_activate(mpath);
 405                         spin_unlock_bh(&mpath->state_lock);
 406                         mesh_path_tx_pending(mpath);
 407                 } else
 408                         spin_unlock_bh(&mpath->state_lock);
 409         }
 410
 411         rcu_read_unlock();
 412
 413         return process ? new_metric : 0;
 414 }
 415
 416 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 417                                     struct ieee80211_mgmt *mgmt,
 418                                     u8 *preq_elem, u32 metric)
 419 {
 420         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 421         struct mesh_path *mpath;
 422         u8 *dst_addr, *orig_addr;
 423         u8 dst_flags, ttl;
 424         u32 orig_dsn, dst_dsn, lifetime;
 425         bool reply = false;
 426         bool forward = true;
 427
 428         /* Update destination DSN, if present */
 429         dst_addr = PREQ_IE_DST_ADDR(preq_elem);
 430         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 431         dst_dsn = PREQ_IE_DST_DSN(preq_elem);
 432         orig_dsn = PREQ_IE_ORIG_DSN(preq_elem);
 433         dst_flags = PREQ_IE_DST_F(preq_elem);
 434
 435         if (memcmp(dst_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
 436                 forward = false;
 437                 reply = true;
 438                 metric = 0;
 439                 if (time_after(jiffies, ifmsh->last_dsn_update +
 440                                         net_traversal_jiffies(sdata)) ||
 441                     time_before(jiffies, ifmsh->last_dsn_update)) {
 442                         dst_dsn = ++ifmsh->dsn;
 443                         ifmsh->last_dsn_update = jiffies;
 444                 }
 445         } else {
 446                 rcu_read_lock();
 447                 mpath = mesh_path_lookup(dst_addr, sdata);
 448                 if (mpath) {
 449                         if ((!(mpath->flags & MESH_PATH_DSN_VALID)) ||
 450                                         DSN_LT(mpath->dsn, dst_dsn)) {
 451                                 mpath->dsn = dst_dsn;
 452                                 mpath->flags |= MESH_PATH_DSN_VALID;
 453                         } else if ((!(dst_flags & MP_F_DO)) &&
 454                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 455                                 reply = true;
 456                                 metric = mpath->metric;
 457                                 dst_dsn = mpath->dsn;
 458                                 if (dst_flags & MP_F_RF)
 459                                         dst_flags |= MP_F_DO;
 460                                 else
 461                                         forward = false;
 462                         }
 463                 }
 464                 rcu_read_unlock();
 465         }
 466
 467         if (reply) {
 468                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 469                 ttl = ifmsh->mshcfg.dot11MeshTTL;
 470                 if (ttl != 0)
 471                         mesh_path_sel_frame_tx(MPATH_PREP, 0, dst_addr,
 472                                 cpu_to_le32(dst_dsn), 0, orig_addr,
 473                                 cpu_to_le32(orig_dsn), mgmt->sa, 0, ttl,
 474                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 475                                 0, sdata);
 476                 else
 477                         ifmsh->mshstats.dropped_frames_ttl++;
 478         }
 479
 480         if (forward) {
 481                 u32 preq_id;
 482                 u8 hopcount, flags;
 483
 484                 ttl = PREQ_IE_TTL(preq_elem);
 485                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 486                 if (ttl <= 1) {
 487                         ifmsh->mshstats.dropped_frames_ttl++;
 488                         return;
 489                 }
 490                 --ttl;
 491                 flags = PREQ_IE_FLAGS(preq_elem);
 492                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 493                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 494                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 495                                 cpu_to_le32(orig_dsn), dst_flags, dst_addr,
 496                                 cpu_to_le32(dst_dsn), sdata->dev->broadcast,
 497                                 hopcount, ttl, cpu_to_le32(lifetime),
 498                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 499                                 sdata);
 500                 ifmsh->mshstats.fwded_mcast++;
 501                 ifmsh->mshstats.fwded_frames++;
 502         }
 503 }
 504
 505
 506 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 507                                     struct ieee80211_mgmt *mgmt,
 508                                     u8 *prep_elem, u32 metric)
 509 {
 510         struct mesh_path *mpath;
 511         u8 *dst_addr, *orig_addr;
 512         u8 ttl, hopcount, flags;
 513         u8 next_hop[ETH_ALEN];
 514         u32 dst_dsn, orig_dsn, lifetime;
 515
 516         /* Note that we divert from the draft nomenclature and denominate
 517          * destination to what the draft refers to as origininator. So in this
 518          * function destnation refers to the final destination of the PREP,
 519          * which corresponds with the originator of the PREQ which this PREP
 520          * replies
 521          */
 522         dst_addr = PREP_IE_DST_ADDR(prep_elem);
 523         if (memcmp(dst_addr, sdata->dev->dev_addr, ETH_ALEN) == 0)
 524                 /* destination, no forwarding required */
 525                 return;
 526
 527         ttl = PREP_IE_TTL(prep_elem);
 528         if (ttl <= 1) {
 529                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 530                 return;
 531         }
 532
 533         rcu_read_lock();
 534         mpath = mesh_path_lookup(dst_addr, sdata);
 535         if (mpath)
 536                 spin_lock_bh(&mpath->state_lock);
 537         else
 538                 goto fail;
 539         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 540                 spin_unlock_bh(&mpath->state_lock);
 541                 goto fail;
 542         }
 543         memcpy(next_hop, mpath->next_hop->sta.addr, ETH_ALEN);
 544         spin_unlock_bh(&mpath->state_lock);
 545         --ttl;
 546         flags = PREP_IE_FLAGS(prep_elem);
 547         lifetime = PREP_IE_LIFETIME(prep_elem);
 548         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 549         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 550         dst_dsn = PREP_IE_DST_DSN(prep_elem);
 551         orig_dsn = PREP_IE_ORIG_DSN(prep_elem);
 552
 553         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 554                 cpu_to_le32(orig_dsn), 0, dst_addr,
 555                 cpu_to_le32(dst_dsn), mpath->next_hop->sta.addr, hopcount, ttl,
 556                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 557                 0, sdata);
 558         rcu_read_unlock();
 559
 560         sdata->u.mesh.mshstats.fwded_unicast++;
 561         sdata->u.mesh.mshstats.fwded_frames++;
 562         return;
 563
 564 fail:
 565         rcu_read_unlock();
 566         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 567         return;
 568 }
 569
 570 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 571                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 572 {
 573         struct mesh_path *mpath;
 574         u8 *ta, *dst_addr;
 575         u32 dst_dsn;
 576
 577         ta = mgmt->sa;
 578         dst_addr = PERR_IE_DST_ADDR(perr_elem);
 579         dst_dsn = PERR_IE_DST_DSN(perr_elem);
 580         rcu_read_lock();
 581         mpath = mesh_path_lookup(dst_addr, sdata);
 582         if (mpath) {
 583                 spin_lock_bh(&mpath->state_lock);
 584                 if (mpath->flags & MESH_PATH_ACTIVE &&
 585                     memcmp(ta, mpath->next_hop->sta.addr, ETH_ALEN) == 0 &&
 586                     (!(mpath->flags & MESH_PATH_DSN_VALID) ||
 587                     DSN_GT(dst_dsn, mpath->dsn))) {
 588                         mpath->flags &= ~MESH_PATH_ACTIVE;
 589                         mpath->dsn = dst_dsn;
 590                         spin_unlock_bh(&mpath->state_lock);
 591                         mesh_path_error_tx(dst_addr, cpu_to_le32(dst_dsn),
 592                                            sdata->dev->broadcast, sdata);
 593                 } else
 594                         spin_unlock_bh(&mpath->state_lock);
 595         }
 596         rcu_read_unlock();
 597 }
 598
 599
 600
 601 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 602                             struct ieee80211_mgmt *mgmt,
 603                             size_t len)
 604 {
 605         struct ieee802_11_elems elems;
 606         size_t baselen;
 607         u32 last_hop_metric;
 608
 609         /* need action_code */
 610         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 611                 return;
 612
 613         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 614         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 615                         len - baselen, &elems);
 616
 617         switch (mgmt->u.action.u.mesh_action.action_code) {
 618         case MPATH_PREQ:
 619                 if (!elems.preq || elems.preq_len != 37)
 620                         /* Right now we support just 1 destination and no AE */
 621                         return;
 622                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq);
 623                 if (!last_hop_metric)
 624                         return;
 625                 hwmp_preq_frame_process(sdata, mgmt, elems.preq, last_hop_metric);
 626                 break;
 627         case MPATH_PREP:
 628                 if (!elems.prep || elems.prep_len != 31)
 629                         /* Right now we support no AE */
 630                         return;
 631                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep);
 632                 if (!last_hop_metric)
 633                         return;
 634                 hwmp_prep_frame_process(sdata, mgmt, elems.prep, last_hop_metric);
 635                 break;
 636         case MPATH_PERR:
 637                 if (!elems.perr || elems.perr_len != 12)
 638                         /* Right now we support only one destination per PERR */
 639                         return;
 640                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 641         default:
 642                 return;
 643         }
 644
 645 }
 646
 647 /**
 648  * mesh_queue_preq - queue a PREQ to a given destination
 649  *
 650  * @mpath: mesh path to discover
 651  * @flags: special attributes of the PREQ to be sent
 652  *
 653  * Locking: the function must be called from within a rcu read lock block.
 654  *
 655  */
 656 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 657 {
 658         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 659         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 660         struct mesh_preq_queue *preq_node;
 661
 662         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 663         if (!preq_node) {
 664                 printk(KERN_DEBUG "Mesh HWMP: could not allocate PREQ node\n");
 665                 return;
 666         }
 667
 668         spin_lock(&ifmsh->mesh_preq_queue_lock);
 669         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 670                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
 671                 kfree(preq_node);
 672                 if (printk_ratelimit())
 673                         printk(KERN_DEBUG "Mesh HWMP: PREQ node queue full\n");
 674                 return;
 675         }
 676
 677         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 678         preq_node->flags = flags;
 679
 680         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 681         ++ifmsh->preq_queue_len;
 682         spin_unlock(&ifmsh->mesh_preq_queue_lock);
 683
 684         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 685                 ieee80211_queue_work(&sdata->local->hw, &ifmsh->work);
 686
 687         else if (time_before(jiffies, ifmsh->last_preq)) {
 688                 /* avoid long wait if did not send preqs for a long time
 689                  * and jiffies wrapped around
 690                  */
 691                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 692                 ieee80211_queue_work(&sdata->local->hw, &ifmsh->work);
 693         } else
 694                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 695                                                 min_preq_int_jiff(sdata));
 696 }
 697
 698 /**
 699  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 700  *
 701  * @sdata: local mesh subif
 702  */
 703 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 704 {
 705         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 706         struct mesh_preq_queue *preq_node;
 707         struct mesh_path *mpath;
 708         u8 ttl, dst_flags;
 709         u32 lifetime;
 710
 711         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 712         if (!ifmsh->preq_queue_len ||
 713                 time_before(jiffies, ifmsh->last_preq +
 714                                 min_preq_int_jiff(sdata))) {
 715                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 716                 return;
 717         }
 718
 719         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 720                         struct mesh_preq_queue, list);
 721         list_del(&preq_node->list);
 722         --ifmsh->preq_queue_len;
 723         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 724
 725         rcu_read_lock();
 726         mpath = mesh_path_lookup(preq_node->dst, sdata);
 727         if (!mpath)
 728                 goto enddiscovery;
 729
 730         spin_lock_bh(&mpath->state_lock);
 731         if (preq_node->flags & PREQ_Q_F_START) {
 732                 if (mpath->flags & MESH_PATH_RESOLVING) {
 733                         spin_unlock_bh(&mpath->state_lock);
 734                         goto enddiscovery;
 735                 } else {
 736                         mpath->flags &= ~MESH_PATH_RESOLVED;
 737                         mpath->flags |= MESH_PATH_RESOLVING;
 738                         mpath->discovery_retries = 0;
 739                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 740                 }
 741         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 742                         mpath->flags & MESH_PATH_RESOLVED) {
 743                 mpath->flags &= ~MESH_PATH_RESOLVING;
 744                 spin_unlock_bh(&mpath->state_lock);
 745                 goto enddiscovery;
 746         }
 747
 748         ifmsh->last_preq = jiffies;
 749
 750         if (time_after(jiffies, ifmsh->last_dsn_update +
 751                                 net_traversal_jiffies(sdata)) ||
 752             time_before(jiffies, ifmsh->last_dsn_update)) {
 753                 ++ifmsh->dsn;
 754                 sdata->u.mesh.last_dsn_update = jiffies;
 755         }
 756         lifetime = default_lifetime(sdata);
 757         ttl = sdata->u.mesh.mshcfg.dot11MeshTTL;
 758         if (ttl == 0) {
 759                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 760                 spin_unlock_bh(&mpath->state_lock);
 761                 goto enddiscovery;
 762         }
 763
 764         if (preq_node->flags & PREQ_Q_F_REFRESH)
 765                 dst_flags = MP_F_DO;
 766         else
 767                 dst_flags = MP_F_RF;
 768
 769         spin_unlock_bh(&mpath->state_lock);
 770         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->dev->dev_addr,
 771                         cpu_to_le32(ifmsh->dsn), dst_flags, mpath->dst,
 772                         cpu_to_le32(mpath->dsn), sdata->dev->broadcast, 0,
 773                         ttl, cpu_to_le32(lifetime), 0,
 774                         cpu_to_le32(ifmsh->preq_id++), sdata);
 775         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 776
 777 enddiscovery:
 778         rcu_read_unlock();
 779         kfree(preq_node);
 780 }
 781
 782 /**
 783  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
 784  *
 785  * @skb: 802.11 frame to be sent
 786  * @sdata: network subif the frame will be sent through
 787  *
 788  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 789  * found, the function will start a path discovery and queue the frame so it is
 790  * sent when the path is resolved. This means the caller must not free the skb
 791  * in this case.
 792  */
 793 int mesh_nexthop_lookup(struct sk_buff *skb,
 794                         struct ieee80211_sub_if_data *sdata)
 795 {
 796         struct sk_buff *skb_to_free = NULL;
 797         struct mesh_path *mpath;
 798         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 799         u8 *dst_addr = hdr->addr3;
 800         int err = 0;
 801
 802         rcu_read_lock();
 803         mpath = mesh_path_lookup(dst_addr, sdata);
 804
 805         if (!mpath) {
 806                 mesh_path_add(dst_addr, sdata);
 807                 mpath = mesh_path_lookup(dst_addr, sdata);
 808                 if (!mpath) {
 809                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 810                         err = -ENOSPC;
 811                         goto endlookup;
 812                 }
 813         }
 814
 815         if (mpath->flags & MESH_PATH_ACTIVE) {
 816                 if (time_after(jiffies, mpath->exp_time +
 817                         msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time))
 818                                 && !memcmp(sdata->dev->dev_addr, hdr->addr4,
 819                                            ETH_ALEN)
 820                                 && !(mpath->flags & MESH_PATH_RESOLVING)
 821                                 && !(mpath->flags & MESH_PATH_FIXED)) {
 822                         mesh_queue_preq(mpath,
 823                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 824                 }
 825                 memcpy(hdr->addr1, mpath->next_hop->sta.addr,
 826                                 ETH_ALEN);
 827         } else {
 828                 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 829                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
 830                         /* Start discovery only if it is not running yet */
 831                         mesh_queue_preq(mpath, PREQ_Q_F_START);
 832                 }
 833
 834                 if (skb_queue_len(&mpath->frame_queue) >=
 835                                 MESH_FRAME_QUEUE_LEN)
 836                         skb_to_free = skb_dequeue(&mpath->frame_queue);
 837
 838                 info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 839                 skb_queue_tail(&mpath->frame_queue, skb);
 840                 if (skb_to_free)
 841                         mesh_path_discard_frame(skb_to_free, sdata);
 842                 err = -ENOENT;
 843         }
 844
 845 endlookup:
 846         rcu_read_unlock();
 847         return err;
 848 }
 849
 850 void mesh_path_timer(unsigned long data)
 851 {
 852         struct ieee80211_sub_if_data *sdata;
 853         struct mesh_path *mpath;
 854
 855         rcu_read_lock();
 856         mpath = (struct mesh_path *) data;
 857         mpath = rcu_dereference(mpath);
 858         if (!mpath)
 859                 goto endmpathtimer;
 860         sdata = mpath->sdata;
 861
 862         if (sdata->local->quiescing) {
 863                 rcu_read_unlock();
 864                 return;
 865         }
 866
 867         spin_lock_bh(&mpath->state_lock);
 868         if (mpath->flags & MESH_PATH_RESOLVED ||
 869                         (!(mpath->flags & MESH_PATH_RESOLVING)))
 870                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
 871         else if (mpath->discovery_retries < max_preq_retries(sdata)) {
 872                 ++mpath->discovery_retries;
 873                 mpath->discovery_timeout *= 2;
 874                 mesh_queue_preq(mpath, 0);
 875         } else {
 876                 mpath->flags = 0;
 877                 mpath->exp_time = jiffies;
 878                 mesh_path_flush_pending(mpath);
 879         }
 880
 881         spin_unlock_bh(&mpath->state_lock);
 882 endmpathtimer:
 883         rcu_read_unlock();
 884 }