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.sta.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  68 #define default_lifetime(s) \
  69         MSEC_TO_TU(s->u.sta.mshcfg.dot11MeshHWMPactivePathTimeout)
  70 #define min_preq_int_jiff(s) \
  71         (msecs_to_jiffies(s->u.sta.mshcfg.dot11MeshHWMPpreqMinInterval))
  72 #define max_preq_retries(s) (s->u.sta.mshcfg.dot11MeshHWMPmaxPREQretries)
  73 #define disc_timeout_jiff(s) \
  74         msecs_to_jiffies(sdata->u.sta.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 net_device *dev)
  86 {
  87         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
  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 = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
 103                                            IEEE80211_STYPE_ACTION);
 104
 105         memcpy(mgmt->da, da, ETH_ALEN);
 106         memcpy(mgmt->sa, 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_sta_tx(dev, 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 net_device *dev)
 165 {
 166         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 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 = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
 182                                            IEEE80211_STYPE_ACTION);
 183
 184         memcpy(mgmt->da, ra, ETH_ALEN);
 185         memcpy(mgmt->sa, 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_sta_tx(dev, 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->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  * @dev: local mesh interface
 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 net_device *dev,
 250                             struct ieee80211_mgmt *mgmt,
 251                             u8 *hwmp_ie)
 252 {
 253         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 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, 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, dev);
 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, dev);
 328                         mpath = mesh_path_lookup(orig_addr, dev);
 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, dev);
 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, dev);
 369                         mpath = mesh_path_lookup(ta, dev);
 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 net_device *dev,
 396                                     struct ieee80211_mgmt *mgmt,
 397                                     u8 *preq_elem, u32 metric) {
 398         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 399         struct ieee80211_if_sta *ifsta = &sdata->u.sta;
 400         struct mesh_path *mpath;
 401         u8 *dst_addr, *orig_addr;
 402         u8 dst_flags, ttl;
 403         u32 orig_dsn, dst_dsn, lifetime;
 404         bool reply = false;
 405         bool forward = true;
 406
 407         /* Update destination DSN, if present */
 408         dst_addr = PREQ_IE_DST_ADDR(preq_elem);
 409         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 410         dst_dsn = PREQ_IE_DST_DSN(preq_elem);
 411         orig_dsn = PREQ_IE_ORIG_DSN(preq_elem);
 412         dst_flags = PREQ_IE_DST_F(preq_elem);
 413
 414         if (memcmp(dst_addr, dev->dev_addr, ETH_ALEN) == 0) {
 415                 forward = false;
 416                 reply = true;
 417                 metric = 0;
 418                 if (time_after(jiffies, ifsta->last_dsn_update +
 419                                         net_traversal_jiffies(sdata)) ||
 420                     time_before(jiffies, ifsta->last_dsn_update)) {
 421                         dst_dsn = ++ifsta->dsn;
 422                         ifsta->last_dsn_update = jiffies;
 423                 }
 424         } else {
 425                 rcu_read_lock();
 426                 mpath = mesh_path_lookup(dst_addr, dev);
 427                 if (mpath) {
 428                         if ((!(mpath->flags & MESH_PATH_DSN_VALID)) ||
 429                                         DSN_LT(mpath->dsn, dst_dsn)) {
 430                                 mpath->dsn = dst_dsn;
 431                                 mpath->flags &= MESH_PATH_DSN_VALID;
 432                         } else if ((!(dst_flags & MP_F_DO)) &&
 433                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 434                                 reply = true;
 435                                 metric = mpath->metric;
 436                                 dst_dsn = mpath->dsn;
 437                                 if (dst_flags & MP_F_RF)
 438                                         dst_flags |= MP_F_DO;
 439                                 else
 440                                         forward = false;
 441                         }
 442                 }
 443                 rcu_read_unlock();
 444         }
 445
 446         if (reply) {
 447                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 448                 ttl = ifsta->mshcfg.dot11MeshTTL;
 449                 if (ttl != 0)
 450                         mesh_path_sel_frame_tx(MPATH_PREP, 0, dst_addr,
 451                                 cpu_to_le32(dst_dsn), 0, orig_addr,
 452                                 cpu_to_le32(orig_dsn), mgmt->sa, 0, ttl,
 453                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 454                                 0, dev);
 455                 else
 456                         ifsta->mshstats.dropped_frames_ttl++;
 457         }
 458
 459         if (forward) {
 460                 u32 preq_id;
 461                 u8 hopcount, flags;
 462
 463                 ttl = PREQ_IE_TTL(preq_elem);
 464                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 465                 if (ttl <= 1) {
 466                         ifsta->mshstats.dropped_frames_ttl++;
 467                         return;
 468                 }
 469                 --ttl;
 470                 flags = PREQ_IE_FLAGS(preq_elem);
 471                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 472                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 473                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 474                                 cpu_to_le32(orig_dsn), dst_flags, dst_addr,
 475                                 cpu_to_le32(dst_dsn), dev->broadcast,
 476                                 hopcount, ttl, cpu_to_le32(lifetime),
 477                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 478                                 dev);
 479                 ifsta->mshstats.fwded_frames++;
 480         }
 481 }
 482
 483
 484 static void hwmp_prep_frame_process(struct net_device *dev,
 485                                     struct ieee80211_mgmt *mgmt,
 486                                     u8 *prep_elem, u32 metric)
 487 {
 488         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 489         struct mesh_path *mpath;
 490         u8 *dst_addr, *orig_addr;
 491         u8 ttl, hopcount, flags;
 492         u8 next_hop[ETH_ALEN];
 493         u32 dst_dsn, orig_dsn, lifetime;
 494
 495         /* Note that we divert from the draft nomenclature and denominate
 496          * destination to what the draft refers to as origininator. So in this
 497          * function destnation refers to the final destination of the PREP,
 498          * which corresponds with the originator of the PREQ which this PREP
 499          * replies
 500          */
 501         dst_addr = PREP_IE_DST_ADDR(prep_elem);
 502         if (memcmp(dst_addr, dev->dev_addr, ETH_ALEN) == 0)
 503                 /* destination, no forwarding required */
 504                 return;
 505
 506         ttl = PREP_IE_TTL(prep_elem);
 507         if (ttl <= 1) {
 508                 sdata->u.sta.mshstats.dropped_frames_ttl++;
 509                 return;
 510         }
 511
 512         rcu_read_lock();
 513         mpath = mesh_path_lookup(dst_addr, dev);
 514         if (mpath)
 515                 spin_lock_bh(&mpath->state_lock);
 516         else
 517                 goto fail;
 518         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 519                 spin_unlock_bh(&mpath->state_lock);
 520                 goto fail;
 521         }
 522         memcpy(next_hop, mpath->next_hop->addr, ETH_ALEN);
 523         spin_unlock_bh(&mpath->state_lock);
 524         --ttl;
 525         flags = PREP_IE_FLAGS(prep_elem);
 526         lifetime = PREP_IE_LIFETIME(prep_elem);
 527         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 528         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 529         dst_dsn = PREP_IE_DST_DSN(prep_elem);
 530         orig_dsn = PREP_IE_ORIG_DSN(prep_elem);
 531
 532         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 533                 cpu_to_le32(orig_dsn), 0, dst_addr,
 534                 cpu_to_le32(dst_dsn), mpath->next_hop->addr, hopcount, ttl,
 535                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 536                 0, dev);
 537         rcu_read_unlock();
 538         sdata->u.sta.mshstats.fwded_frames++;
 539         return;
 540
 541 fail:
 542         rcu_read_unlock();
 543         sdata->u.sta.mshstats.dropped_frames_no_route++;
 544         return;
 545 }
 546
 547 static void hwmp_perr_frame_process(struct net_device *dev,
 548                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 549 {
 550         struct mesh_path *mpath;
 551         u8 *ta, *dst_addr;
 552         u32 dst_dsn;
 553
 554         ta = mgmt->sa;
 555         dst_addr = PERR_IE_DST_ADDR(perr_elem);
 556         dst_dsn = PERR_IE_DST_DSN(perr_elem);
 557         rcu_read_lock();
 558         mpath = mesh_path_lookup(dst_addr, dev);
 559         if (mpath) {
 560                 spin_lock_bh(&mpath->state_lock);
 561                 if (mpath->flags & MESH_PATH_ACTIVE &&
 562                     memcmp(ta, mpath->next_hop->addr, ETH_ALEN) == 0 &&
 563                     (!(mpath->flags & MESH_PATH_DSN_VALID) ||
 564                     DSN_GT(dst_dsn, mpath->dsn))) {
 565                         mpath->flags &= ~MESH_PATH_ACTIVE;
 566                         mpath->dsn = dst_dsn;
 567                         spin_unlock_bh(&mpath->state_lock);
 568                         mesh_path_error_tx(dst_addr, cpu_to_le32(dst_dsn),
 569                                            dev->broadcast, dev);
 570                 } else
 571                         spin_unlock_bh(&mpath->state_lock);
 572         }
 573         rcu_read_unlock();
 574 }
 575
 576
 577
 578 void mesh_rx_path_sel_frame(struct net_device *dev,
 579                             struct ieee80211_mgmt *mgmt,
 580                             size_t len)
 581 {
 582         struct ieee802_11_elems elems;
 583         size_t baselen;
 584         u32 last_hop_metric;
 585
 586         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 587         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 588                         len - baselen, &elems);
 589
 590         switch (mgmt->u.action.u.mesh_action.action_code) {
 591         case MPATH_PREQ:
 592                 if (!elems.preq || elems.preq_len != 37)
 593                         /* Right now we support just 1 destination and no AE */
 594                         return;
 595                 last_hop_metric = hwmp_route_info_get(dev, mgmt, elems.preq);
 596                 if (!last_hop_metric)
 597                         return;
 598                 hwmp_preq_frame_process(dev, mgmt, elems.preq, last_hop_metric);
 599                 break;
 600         case MPATH_PREP:
 601                 if (!elems.prep || elems.prep_len != 31)
 602                         /* Right now we support no AE */
 603                         return;
 604                 last_hop_metric = hwmp_route_info_get(dev, mgmt, elems.prep);
 605                 if (!last_hop_metric)
 606                         return;
 607                 hwmp_prep_frame_process(dev, mgmt, elems.prep, last_hop_metric);
 608                 break;
 609         case MPATH_PERR:
 610                 if (!elems.perr || elems.perr_len != 12)
 611                         /* Right now we support only one destination per PERR */
 612                         return;
 613                 hwmp_perr_frame_process(dev, mgmt, elems.perr);
 614         default:
 615                 return;
 616         }
 617
 618 }
 619
 620 /**
 621  * mesh_queue_preq - queue a PREQ to a given destination
 622  *
 623  * @mpath: mesh path to discover
 624  * @flags: special attributes of the PREQ to be sent
 625  *
 626  * Locking: the function must be called from within a rcu read lock block.
 627  *
 628  */
 629 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 630 {
 631         struct ieee80211_sub_if_data *sdata =
 632                 IEEE80211_DEV_TO_SUB_IF(mpath->dev);
 633         struct ieee80211_if_sta *ifsta = &sdata->u.sta;
 634         struct mesh_preq_queue *preq_node;
 635
 636         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_KERNEL);
 637         if (!preq_node) {
 638                 printk(KERN_DEBUG "Mesh HWMP: could not allocate PREQ node\n");
 639                 return;
 640         }
 641
 642         spin_lock(&ifsta->mesh_preq_queue_lock);
 643         if (ifsta->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 644                 spin_unlock(&ifsta->mesh_preq_queue_lock);
 645                 kfree(preq_node);
 646                 if (printk_ratelimit())
 647                         printk(KERN_DEBUG "Mesh HWMP: PREQ node queue full\n");
 648                 return;
 649         }
 650
 651         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 652         preq_node->flags = flags;
 653
 654         list_add_tail(&preq_node->list, &ifsta->preq_queue.list);
 655         ++ifsta->preq_queue_len;
 656         spin_unlock(&ifsta->mesh_preq_queue_lock);
 657
 658         if (time_after(jiffies, ifsta->last_preq + min_preq_int_jiff(sdata)))
 659                 queue_work(sdata->local->hw.workqueue, &ifsta->work);
 660
 661         else if (time_before(jiffies, ifsta->last_preq)) {
 662                 /* avoid long wait if did not send preqs for a long time
 663                  * and jiffies wrapped around
 664                  */
 665                 ifsta->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 666                 queue_work(sdata->local->hw.workqueue, &ifsta->work);
 667         } else
 668                 mod_timer(&ifsta->mesh_path_timer, ifsta->last_preq +
 669                                                 min_preq_int_jiff(sdata));
 670 }
 671
 672 /**
 673  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 674  *
 675  * @dev: local mesh interface
 676  */
 677 void mesh_path_start_discovery(struct net_device *dev)
 678 {
 679         struct ieee80211_sub_if_data *sdata =
 680                 IEEE80211_DEV_TO_SUB_IF(dev);
 681         struct ieee80211_if_sta *ifsta = &sdata->u.sta;
 682         struct mesh_preq_queue *preq_node;
 683         struct mesh_path *mpath;
 684         u8 ttl, dst_flags;
 685         u32 lifetime;
 686
 687         spin_lock(&ifsta->mesh_preq_queue_lock);
 688         if (!ifsta->preq_queue_len ||
 689                 time_before(jiffies, ifsta->last_preq +
 690                                 min_preq_int_jiff(sdata))) {
 691                 spin_unlock(&ifsta->mesh_preq_queue_lock);
 692                 return;
 693         }
 694
 695         preq_node = list_first_entry(&ifsta->preq_queue.list,
 696                         struct mesh_preq_queue, list);
 697         list_del(&preq_node->list);
 698         --ifsta->preq_queue_len;
 699         spin_unlock(&ifsta->mesh_preq_queue_lock);
 700
 701         rcu_read_lock();
 702         mpath = mesh_path_lookup(preq_node->dst, dev);
 703         if (!mpath)
 704                 goto enddiscovery;
 705
 706         spin_lock_bh(&mpath->state_lock);
 707         if (preq_node->flags & PREQ_Q_F_START) {
 708                 if (mpath->flags & MESH_PATH_RESOLVING) {
 709                         spin_unlock_bh(&mpath->state_lock);
 710                         goto enddiscovery;
 711                 } else {
 712                         mpath->flags &= ~MESH_PATH_RESOLVED;
 713                         mpath->flags |= MESH_PATH_RESOLVING;
 714                         mpath->discovery_retries = 0;
 715                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 716                 }
 717         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 718                         mpath->flags & MESH_PATH_RESOLVED) {
 719                 mpath->flags &= ~MESH_PATH_RESOLVING;
 720                 spin_unlock_bh(&mpath->state_lock);
 721                 goto enddiscovery;
 722         }
 723
 724         ifsta->last_preq = jiffies;
 725
 726         if (time_after(jiffies, ifsta->last_dsn_update +
 727                                 net_traversal_jiffies(sdata)) ||
 728             time_before(jiffies, ifsta->last_dsn_update)) {
 729                 ++ifsta->dsn;
 730                 sdata->u.sta.last_dsn_update = jiffies;
 731         }
 732         lifetime = default_lifetime(sdata);
 733         ttl = sdata->u.sta.mshcfg.dot11MeshTTL;
 734         if (ttl == 0) {
 735                 sdata->u.sta.mshstats.dropped_frames_ttl++;
 736                 spin_unlock_bh(&mpath->state_lock);
 737                 goto enddiscovery;
 738         }
 739
 740         if (preq_node->flags & PREQ_Q_F_REFRESH)
 741                 dst_flags = MP_F_DO;
 742         else
 743                 dst_flags = MP_F_RF;
 744
 745         spin_unlock_bh(&mpath->state_lock);
 746         mesh_path_sel_frame_tx(MPATH_PREQ, 0, dev->dev_addr,
 747                         cpu_to_le32(ifsta->dsn), dst_flags, mpath->dst,
 748                         cpu_to_le32(mpath->dsn), dev->broadcast, 0,
 749                         ttl, cpu_to_le32(lifetime), 0,
 750                         cpu_to_le32(ifsta->preq_id++), dev);
 751         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 752
 753 enddiscovery:
 754         rcu_read_unlock();
 755         kfree(preq_node);
 756 }
 757
 758 /**
 759  * ieee80211s_lookup_nexthop - put the appropriate next hop on a mesh frame
 760  *
 761  * @next_hop: output argument for next hop address
 762  * @skb: frame to be sent
 763  * @dev: network device the frame will be sent through
 764  *
 765  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 766  * found, the function will start a path discovery and queue the frame so it is
 767  * sent when the path is resolved. This means the caller must not free the skb
 768  * in this case.
 769  */
 770 int mesh_nexthop_lookup(u8 *next_hop, struct sk_buff *skb,
 771                 struct net_device *dev)
 772 {
 773         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 774         struct sk_buff *skb_to_free = NULL;
 775         struct mesh_path *mpath;
 776         int err = 0;
 777
 778         rcu_read_lock();
 779         mpath = mesh_path_lookup(skb->data, dev);
 780
 781         if (!mpath) {
 782                 mesh_path_add(skb->data, dev);
 783                 mpath = mesh_path_lookup(skb->data, dev);
 784                 if (!mpath) {
 785                         dev_kfree_skb(skb);
 786                         sdata->u.sta.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.sta.mshcfg.path_refresh_time))
 795                                 && skb->pkt_type != PACKET_OTHERHOST
 796                                 && !(mpath->flags & MESH_PATH_RESOLVING)
 797                                 && !(mpath->flags & MESH_PATH_FIXED)) {
 798                         mesh_queue_preq(mpath,
 799                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 800                 }
 801                 memcpy(next_hop, mpath->next_hop->addr,
 802                                 ETH_ALEN);
 803         } else {
 804                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
 805                         /* Start discovery only if it is not running yet */
 806                         mesh_queue_preq(mpath, PREQ_Q_F_START);
 807                 }
 808
 809                 if (skb_queue_len(&mpath->frame_queue) >=
 810                                 MESH_FRAME_QUEUE_LEN) {
 811                         skb_to_free = mpath->frame_queue.next;
 812                         skb_unlink(skb_to_free, &mpath->frame_queue);
 813                 }
 814
 815                 skb_queue_tail(&mpath->frame_queue, skb);
 816                 if (skb_to_free)
 817                         mesh_path_discard_frame(skb_to_free, dev);
 818                 err = -ENOENT;
 819         }
 820
 821 endlookup:
 822         rcu_read_unlock();
 823         return err;
 824 }
 825
 826 void mesh_path_timer(unsigned long data)
 827 {
 828         struct ieee80211_sub_if_data *sdata;
 829         struct mesh_path *mpath;
 830
 831         rcu_read_lock();
 832         mpath = (struct mesh_path *) data;
 833         mpath = rcu_dereference(mpath);
 834         if (!mpath)
 835                 goto endmpathtimer;
 836         spin_lock_bh(&mpath->state_lock);
 837         sdata = IEEE80211_DEV_TO_SUB_IF(mpath->dev);
 838         if (mpath->flags & MESH_PATH_RESOLVED ||
 839                         (!(mpath->flags & MESH_PATH_RESOLVING)))
 840                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
 841         else if (mpath->discovery_retries < max_preq_retries(sdata)) {
 842                 ++mpath->discovery_retries;
 843                 mpath->discovery_timeout *= 2;
 844                 mesh_queue_preq(mpath, 0);
 845         } else {
 846                 mpath->flags = 0;
 847                 mpath->exp_time = jiffies;
 848                 mesh_path_flush_pending(mpath);
 849         }
 850
 851         spin_unlock_bh(&mpath->state_lock);
 852 endmpathtimer:
 853         rcu_read_unlock();
 854 }