net/mac80211/mesh_hwmp.c

   1 /*
   2  * Copyright (c) 2008, 2009 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 #ifdef CONFIG_MAC80211_VERBOSE_MHWMP_DEBUG
  13 #define mhwmp_dbg(fmt, args...)   printk(KERN_DEBUG "Mesh HWMP: " fmt, ##args)
  14 #else
  15 #define mhwmp_dbg(fmt, args...)   do { (void)(0); } while (0)
  16 #endif
  17
  18 #define TEST_FRAME_LEN  8192
  19 #define MAX_METRIC      0xffffffff
  20 #define ARITH_SHIFT     8
  21
  22 /* Number of frames buffered per destination for unresolved destinations */
  23 #define MESH_FRAME_QUEUE_LEN    10
  24 #define MAX_PREQ_QUEUE_LEN      64
  25
  26 /* Destination only */
  27 #define MP_F_DO 0x1
  28 /* Reply and forward */
  29 #define MP_F_RF 0x2
  30 /* Unknown Sequence Number */
  31 #define MP_F_USN    0x01
  32 /* Reason code Present */
  33 #define MP_F_RCODE  0x02
  34
  35 static void mesh_queue_preq(struct mesh_path *, u8);
  36
  37 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
  38 {
  39         if (ae)
  40                 offset += 6;
  41         return get_unaligned_le32(preq_elem + offset);
  42 }
  43
  44 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
  45 {
  46         if (ae)
  47                 offset += 6;
  48         return get_unaligned_le16(preq_elem + offset);
  49 }
  50
  51 /* HWMP IE processing macros */
  52 #define AE_F                    (1<<6)
  53 #define AE_F_SET(x)             (*x & AE_F)
  54 #define PREQ_IE_FLAGS(x)        (*(x))
  55 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  56 #define PREQ_IE_TTL(x)          (*(x + 2))
  57 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  58 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  59 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0);
  60 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x));
  61 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x));
  62 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  63 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  64 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x));
  65
  66
  67 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  68 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  69 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  70 #define PREP_IE_ORIG_ADDR(x)    (x + 3)
  71 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 9, 0);
  72 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x));
  73 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x));
  74 #define PREP_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 27 : x + 21)
  75 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 27, AE_F_SET(x));
  76
  77 #define PERR_IE_TTL(x)          (*(x))
  78 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  79 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  80 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0);
  81 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0);
  82
  83 #define MSEC_TO_TU(x) (x*1000/1024)
  84 #define SN_GT(x, y) ((long) (y) - (long) (x) < 0)
  85 #define SN_LT(x, y) ((long) (x) - (long) (y) < 0)
  86
  87 #define net_traversal_jiffies(s) \
  88         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  89 #define default_lifetime(s) \
  90         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  91 #define min_preq_int_jiff(s) \
  92         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  93 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  94 #define disc_timeout_jiff(s) \
  95         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  96
  97 enum mpath_frame_type {
  98         MPATH_PREQ = 0,
  99         MPATH_PREP,
 100         MPATH_PERR,
 101         MPATH_RANN
 102 };
 103
 104 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 105
 106 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 107                 u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
 108                 __le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
 109                 __le32 lifetime, __le32 metric, __le32 preq_id,
 110                 struct ieee80211_sub_if_data *sdata)
 111 {
 112         struct ieee80211_local *local = sdata->local;
 113         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
 114         struct ieee80211_mgmt *mgmt;
 115         u8 *pos;
 116         int ie_len;
 117
 118         if (!skb)
 119                 return -1;
 120         skb_reserve(skb, local->hw.extra_tx_headroom);
 121         /* 25 is the size of the common mgmt part (24) plus the size of the
 122          * common action part (1)
 123          */
 124         mgmt = (struct ieee80211_mgmt *)
 125                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 126         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 127         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 128                                           IEEE80211_STYPE_ACTION);
 129
 130         memcpy(mgmt->da, da, ETH_ALEN);
 131         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 132         /* BSSID == SA */
 133         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 134         mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
 135         mgmt->u.action.u.mesh_action.action_code = MESH_PATH_SEL_ACTION;
 136
 137         switch (action) {
 138         case MPATH_PREQ:
 139                 mhwmp_dbg("sending PREQ to %pM\n", target);
 140                 ie_len = 37;
 141                 pos = skb_put(skb, 2 + ie_len);
 142                 *pos++ = WLAN_EID_PREQ;
 143                 break;
 144         case MPATH_PREP:
 145                 mhwmp_dbg("sending PREP to %pM\n", target);
 146                 ie_len = 31;
 147                 pos = skb_put(skb, 2 + ie_len);
 148                 *pos++ = WLAN_EID_PREP;
 149                 break;
 150         case MPATH_RANN:
 151                 mhwmp_dbg("sending RANN from %pM\n", orig_addr);
 152                 ie_len = sizeof(struct ieee80211_rann_ie);
 153                 pos = skb_put(skb, 2 + ie_len);
 154                 *pos++ = WLAN_EID_RANN;
 155                 break;
 156         default:
 157                 kfree_skb(skb);
 158                 return -ENOTSUPP;
 159                 break;
 160         }
 161         *pos++ = ie_len;
 162         *pos++ = flags;
 163         *pos++ = hop_count;
 164         *pos++ = ttl;
 165         if (action == MPATH_PREQ) {
 166                 memcpy(pos, &preq_id, 4);
 167                 pos += 4;
 168         }
 169         memcpy(pos, orig_addr, ETH_ALEN);
 170         pos += ETH_ALEN;
 171         memcpy(pos, &orig_sn, 4);
 172         pos += 4;
 173         if (action != MPATH_RANN) {
 174                 memcpy(pos, &lifetime, 4);
 175                 pos += 4;
 176         }
 177         memcpy(pos, &metric, 4);
 178         pos += 4;
 179         if (action == MPATH_PREQ) {
 180                 /* destination count */
 181                 *pos++ = 1;
 182                 *pos++ = target_flags;
 183         }
 184         if (action != MPATH_RANN) {
 185                 memcpy(pos, target, ETH_ALEN);
 186                 pos += ETH_ALEN;
 187                 memcpy(pos, &target_sn, 4);
 188         }
 189
 190         ieee80211_tx_skb(sdata, skb);
 191         return 0;
 192 }
 193
 194 /**
 195  * mesh_send_path error - Sends a PERR mesh management frame
 196  *
 197  * @target: broken destination
 198  * @target_sn: SN of the broken destination
 199  * @target_rcode: reason code for this PERR
 200  * @ra: node this frame is addressed to
 201  */
 202 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 203                        __le16 target_rcode, const u8 *ra,
 204                        struct ieee80211_sub_if_data *sdata)
 205 {
 206         struct ieee80211_local *local = sdata->local;
 207         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
 208         struct ieee80211_mgmt *mgmt;
 209         u8 *pos;
 210         int ie_len;
 211
 212         if (!skb)
 213                 return -1;
 214         skb_reserve(skb, local->hw.extra_tx_headroom);
 215         /* 25 is the size of the common mgmt part (24) plus the size of the
 216          * common action part (1)
 217          */
 218         mgmt = (struct ieee80211_mgmt *)
 219                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 220         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 221         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 222                                           IEEE80211_STYPE_ACTION);
 223
 224         memcpy(mgmt->da, ra, ETH_ALEN);
 225         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 226         /* BSSID is left zeroed, wildcard value */
 227         mgmt->u.action.category = MESH_PATH_SEL_CATEGORY;
 228         mgmt->u.action.u.mesh_action.action_code = MESH_PATH_SEL_ACTION;
 229         ie_len = 15;
 230         pos = skb_put(skb, 2 + ie_len);
 231         *pos++ = WLAN_EID_PERR;
 232         *pos++ = ie_len;
 233         /* ttl */
 234         *pos++ = MESH_TTL;
 235         /* number of destinations */
 236         *pos++ = 1;
 237         /*
 238          * flags bit, bit 1 is unset if we know the sequence number and
 239          * bit 2 is set if we have a reason code
 240          */
 241         *pos = 0;
 242         if (!target_sn)
 243                 *pos |= MP_F_USN;
 244         if (target_rcode)
 245                 *pos |= MP_F_RCODE;
 246         pos++;
 247         memcpy(pos, target, ETH_ALEN);
 248         pos += ETH_ALEN;
 249         memcpy(pos, &target_sn, 4);
 250         pos += 4;
 251         memcpy(pos, &target_rcode, 2);
 252
 253         ieee80211_tx_skb(sdata, skb);
 254         return 0;
 255 }
 256
 257 void ieee80211s_update_metric(struct ieee80211_local *local,
 258                 struct sta_info *stainfo, struct sk_buff *skb)
 259 {
 260         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 261         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 262         int failed;
 263
 264         if (!ieee80211_is_data(hdr->frame_control))
 265                 return;
 266
 267         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 268
 269         /* moving average, scaled to 100 */
 270         stainfo->fail_avg = ((80 * stainfo->fail_avg + 5) / 100 + 20 * failed);
 271         if (stainfo->fail_avg > 95)
 272                 mesh_plink_broken(stainfo);
 273 }
 274
 275 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 276                                    struct sta_info *sta)
 277 {
 278         struct ieee80211_supported_band *sband;
 279         /* This should be adjusted for each device */
 280         int device_constant = 1 << ARITH_SHIFT;
 281         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 282         int s_unit = 1 << ARITH_SHIFT;
 283         int rate, err;
 284         u32 tx_time, estimated_retx;
 285         u64 result;
 286
 287         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 288
 289         if (sta->fail_avg >= 100)
 290                 return MAX_METRIC;
 291
 292         if (sta->last_tx_rate.flags & IEEE80211_TX_RC_MCS)
 293                 return MAX_METRIC;
 294
 295         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 296
 297         /* bitrate is in units of 100 Kbps, while we need rate in units of
 298          * 1Mbps. This will be corrected on tx_time computation.
 299          */
 300         rate = sband->bitrates[sta->last_tx_rate.idx].bitrate;
 301         tx_time = (device_constant + 10 * test_frame_len / rate);
 302         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 303         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 304         return (u32)result;
 305 }
 306
 307 /**
 308  * hwmp_route_info_get - Update routing info to originator and transmitter
 309  *
 310  * @sdata: local mesh subif
 311  * @mgmt: mesh management frame
 312  * @hwmp_ie: hwmp information element (PREP or PREQ)
 313  *
 314  * This function updates the path routing information to the originator and the
 315  * transmitter of a HWMP PREQ or PREP frame.
 316  *
 317  * Returns: metric to frame originator or 0 if the frame should not be further
 318  * processed
 319  *
 320  * Notes: this function is the only place (besides user-provided info) where
 321  * path routing information is updated.
 322  */
 323 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 324                             struct ieee80211_mgmt *mgmt,
 325                             u8 *hwmp_ie, enum mpath_frame_type action)
 326 {
 327         struct ieee80211_local *local = sdata->local;
 328         struct mesh_path *mpath;
 329         struct sta_info *sta;
 330         bool fresh_info;
 331         u8 *orig_addr, *ta;
 332         u32 orig_sn, orig_metric;
 333         unsigned long orig_lifetime, exp_time;
 334         u32 last_hop_metric, new_metric;
 335         bool process = true;
 336
 337         rcu_read_lock();
 338         sta = sta_info_get(sdata, mgmt->sa);
 339         if (!sta) {
 340                 rcu_read_unlock();
 341                 return 0;
 342         }
 343
 344         last_hop_metric = airtime_link_metric_get(local, sta);
 345         /* Update and check originator routing info */
 346         fresh_info = true;
 347
 348         switch (action) {
 349         case MPATH_PREQ:
 350                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 351                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 352                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 353                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 354                 break;
 355         case MPATH_PREP:
 356                 /* Originator here refers to the MP that was the destination in
 357                  * the Path Request. The draft refers to that MP as the
 358                  * destination address, even though usually it is the origin of
 359                  * the PREP frame. We divert from the nomenclature in the draft
 360                  * so that we can easily use a single function to gather path
 361                  * information from both PREQ and PREP frames.
 362                  */
 363                 orig_addr = PREP_IE_ORIG_ADDR(hwmp_ie);
 364                 orig_sn = PREP_IE_ORIG_SN(hwmp_ie);
 365                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 366                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 367                 break;
 368         default:
 369                 rcu_read_unlock();
 370                 return 0;
 371         }
 372         new_metric = orig_metric + last_hop_metric;
 373         if (new_metric < orig_metric)
 374                 new_metric = MAX_METRIC;
 375         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 376
 377         if (memcmp(orig_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 378                 /* This MP is the originator, we are not interested in this
 379                  * frame, except for updating transmitter's path info.
 380                  */
 381                 process = false;
 382                 fresh_info = false;
 383         } else {
 384                 mpath = mesh_path_lookup(orig_addr, sdata);
 385                 if (mpath) {
 386                         spin_lock_bh(&mpath->state_lock);
 387                         if (mpath->flags & MESH_PATH_FIXED)
 388                                 fresh_info = false;
 389                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 390                             (mpath->flags & MESH_PATH_SN_VALID)) {
 391                                 if (SN_GT(mpath->sn, orig_sn) ||
 392                                     (mpath->sn == orig_sn &&
 393                                      action == MPATH_PREQ &&
 394                                      new_metric > mpath->metric)) {
 395                                         process = false;
 396                                         fresh_info = false;
 397                                 }
 398                         }
 399                 } else {
 400                         mesh_path_add(orig_addr, sdata);
 401                         mpath = mesh_path_lookup(orig_addr, sdata);
 402                         if (!mpath) {
 403                                 rcu_read_unlock();
 404                                 return 0;
 405                         }
 406                         spin_lock_bh(&mpath->state_lock);
 407                 }
 408
 409                 if (fresh_info) {
 410                         mesh_path_assign_nexthop(mpath, sta);
 411                         mpath->flags |= MESH_PATH_SN_VALID;
 412                         mpath->metric = new_metric;
 413                         mpath->sn = orig_sn;
 414                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 415                                           ?  mpath->exp_time : exp_time;
 416                         mesh_path_activate(mpath);
 417                         spin_unlock_bh(&mpath->state_lock);
 418                         mesh_path_tx_pending(mpath);
 419                         /* draft says preq_id should be saved to, but there does
 420                          * not seem to be any use for it, skipping by now
 421                          */
 422                 } else
 423                         spin_unlock_bh(&mpath->state_lock);
 424         }
 425
 426         /* Update and check transmitter routing info */
 427         ta = mgmt->sa;
 428         if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
 429                 fresh_info = false;
 430         else {
 431                 fresh_info = true;
 432
 433                 mpath = mesh_path_lookup(ta, sdata);
 434                 if (mpath) {
 435                         spin_lock_bh(&mpath->state_lock);
 436                         if ((mpath->flags & MESH_PATH_FIXED) ||
 437                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 438                                         (last_hop_metric > mpath->metric)))
 439                                 fresh_info = false;
 440                 } else {
 441                         mesh_path_add(ta, sdata);
 442                         mpath = mesh_path_lookup(ta, sdata);
 443                         if (!mpath) {
 444                                 rcu_read_unlock();
 445                                 return 0;
 446                         }
 447                         spin_lock_bh(&mpath->state_lock);
 448                 }
 449
 450                 if (fresh_info) {
 451                         mesh_path_assign_nexthop(mpath, sta);
 452                         mpath->flags &= ~MESH_PATH_SN_VALID;
 453                         mpath->metric = last_hop_metric;
 454                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 455                                           ?  mpath->exp_time : exp_time;
 456                         mesh_path_activate(mpath);
 457                         spin_unlock_bh(&mpath->state_lock);
 458                         mesh_path_tx_pending(mpath);
 459                 } else
 460                         spin_unlock_bh(&mpath->state_lock);
 461         }
 462
 463         rcu_read_unlock();
 464
 465         return process ? new_metric : 0;
 466 }
 467
 468 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 469                                     struct ieee80211_mgmt *mgmt,
 470                                     u8 *preq_elem, u32 metric)
 471 {
 472         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 473         struct mesh_path *mpath;
 474         u8 *target_addr, *orig_addr;
 475         u8 target_flags, ttl;
 476         u32 orig_sn, target_sn, lifetime;
 477         bool reply = false;
 478         bool forward = true;
 479
 480         /* Update target SN, if present */
 481         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 482         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 483         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 484         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 485         target_flags = PREQ_IE_TARGET_F(preq_elem);
 486
 487         mhwmp_dbg("received PREQ from %pM\n", orig_addr);
 488
 489         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 490                 mhwmp_dbg("PREQ is for us\n");
 491                 forward = false;
 492                 reply = true;
 493                 metric = 0;
 494                 if (time_after(jiffies, ifmsh->last_sn_update +
 495                                         net_traversal_jiffies(sdata)) ||
 496                     time_before(jiffies, ifmsh->last_sn_update)) {
 497                         target_sn = ++ifmsh->sn;
 498                         ifmsh->last_sn_update = jiffies;
 499                 }
 500         } else {
 501                 rcu_read_lock();
 502                 mpath = mesh_path_lookup(target_addr, sdata);
 503                 if (mpath) {
 504                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 505                                         SN_LT(mpath->sn, target_sn)) {
 506                                 mpath->sn = target_sn;
 507                                 mpath->flags |= MESH_PATH_SN_VALID;
 508                         } else if ((!(target_flags & MP_F_DO)) &&
 509                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 510                                 reply = true;
 511                                 metric = mpath->metric;
 512                                 target_sn = mpath->sn;
 513                                 if (target_flags & MP_F_RF)
 514                                         target_flags |= MP_F_DO;
 515                                 else
 516                                         forward = false;
 517                         }
 518                 }
 519                 rcu_read_unlock();
 520         }
 521
 522         if (reply) {
 523                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 524                 ttl = ifmsh->mshcfg.dot11MeshTTL;
 525                 if (ttl != 0) {
 526                         mhwmp_dbg("replying to the PREQ\n");
 527                         mesh_path_sel_frame_tx(MPATH_PREP, 0, target_addr,
 528                                 cpu_to_le32(target_sn), 0, orig_addr,
 529                                 cpu_to_le32(orig_sn), mgmt->sa, 0, ttl,
 530                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 531                                 0, sdata);
 532                 } else
 533                         ifmsh->mshstats.dropped_frames_ttl++;
 534         }
 535
 536         if (forward) {
 537                 u32 preq_id;
 538                 u8 hopcount, flags;
 539
 540                 ttl = PREQ_IE_TTL(preq_elem);
 541                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 542                 if (ttl <= 1) {
 543                         ifmsh->mshstats.dropped_frames_ttl++;
 544                         return;
 545                 }
 546                 mhwmp_dbg("forwarding the PREQ from %pM\n", orig_addr);
 547                 --ttl;
 548                 flags = PREQ_IE_FLAGS(preq_elem);
 549                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 550                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 551                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 552                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 553                                 cpu_to_le32(target_sn), broadcast_addr,
 554                                 hopcount, ttl, cpu_to_le32(lifetime),
 555                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 556                                 sdata);
 557                 ifmsh->mshstats.fwded_mcast++;
 558                 ifmsh->mshstats.fwded_frames++;
 559         }
 560 }
 561
 562
 563 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 564                                     struct ieee80211_mgmt *mgmt,
 565                                     u8 *prep_elem, u32 metric)
 566 {
 567         struct mesh_path *mpath;
 568         u8 *target_addr, *orig_addr;
 569         u8 ttl, hopcount, flags;
 570         u8 next_hop[ETH_ALEN];
 571         u32 target_sn, orig_sn, lifetime;
 572
 573         mhwmp_dbg("received PREP from %pM\n", PREP_IE_ORIG_ADDR(prep_elem));
 574
 575         /* Note that we divert from the draft nomenclature and denominate
 576          * destination to what the draft refers to as origininator. So in this
 577          * function destnation refers to the final destination of the PREP,
 578          * which corresponds with the originator of the PREQ which this PREP
 579          * replies
 580          */
 581         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 582         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0)
 583                 /* destination, no forwarding required */
 584                 return;
 585
 586         ttl = PREP_IE_TTL(prep_elem);
 587         if (ttl <= 1) {
 588                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 589                 return;
 590         }
 591
 592         rcu_read_lock();
 593         mpath = mesh_path_lookup(target_addr, sdata);
 594         if (mpath)
 595                 spin_lock_bh(&mpath->state_lock);
 596         else
 597                 goto fail;
 598         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 599                 spin_unlock_bh(&mpath->state_lock);
 600                 goto fail;
 601         }
 602         memcpy(next_hop, mpath->next_hop->sta.addr, ETH_ALEN);
 603         spin_unlock_bh(&mpath->state_lock);
 604         --ttl;
 605         flags = PREP_IE_FLAGS(prep_elem);
 606         lifetime = PREP_IE_LIFETIME(prep_elem);
 607         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 608         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 609         target_sn = PREP_IE_TARGET_SN(prep_elem);
 610         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 611
 612         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 613                 cpu_to_le32(orig_sn), 0, target_addr,
 614                 cpu_to_le32(target_sn), mpath->next_hop->sta.addr, hopcount,
 615                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 616                 0, sdata);
 617         rcu_read_unlock();
 618
 619         sdata->u.mesh.mshstats.fwded_unicast++;
 620         sdata->u.mesh.mshstats.fwded_frames++;
 621         return;
 622
 623 fail:
 624         rcu_read_unlock();
 625         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 626         return;
 627 }
 628
 629 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 630                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 631 {
 632         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 633         struct mesh_path *mpath;
 634         u8 ttl;
 635         u8 *ta, *target_addr;
 636         u8 target_flags;
 637         u32 target_sn;
 638         u16 target_rcode;
 639
 640         ta = mgmt->sa;
 641         ttl = PERR_IE_TTL(perr_elem);
 642         if (ttl <= 1) {
 643                 ifmsh->mshstats.dropped_frames_ttl++;
 644                 return;
 645         }
 646         ttl--;
 647         target_flags = PERR_IE_TARGET_FLAGS(perr_elem);
 648         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 649         target_sn = PERR_IE_TARGET_SN(perr_elem);
 650         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 651
 652         rcu_read_lock();
 653         mpath = mesh_path_lookup(target_addr, sdata);
 654         if (mpath) {
 655                 spin_lock_bh(&mpath->state_lock);
 656                 if (mpath->flags & MESH_PATH_ACTIVE &&
 657                     memcmp(ta, mpath->next_hop->sta.addr, ETH_ALEN) == 0 &&
 658                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 659                     SN_GT(target_sn, mpath->sn))) {
 660                         mpath->flags &= ~MESH_PATH_ACTIVE;
 661                         mpath->sn = target_sn;
 662                         spin_unlock_bh(&mpath->state_lock);
 663                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 664                                            cpu_to_le16(target_rcode),
 665                                            broadcast_addr, sdata);
 666                 } else
 667                         spin_unlock_bh(&mpath->state_lock);
 668         }
 669         rcu_read_unlock();
 670 }
 671
 672 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 673                                 struct ieee80211_mgmt *mgmt,
 674                                 struct ieee80211_rann_ie *rann)
 675 {
 676         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 677         struct mesh_path *mpath;
 678         u8 *ta;
 679         u8 ttl, flags, hopcount;
 680         u8 *orig_addr;
 681         u32 orig_sn, metric;
 682
 683         ta = mgmt->sa;
 684         ttl = rann->rann_ttl;
 685         if (ttl <= 1) {
 686                 ifmsh->mshstats.dropped_frames_ttl++;
 687                 return;
 688         }
 689         ttl--;
 690         flags = rann->rann_flags;
 691         orig_addr = rann->rann_addr;
 692         orig_sn = rann->rann_seq;
 693         hopcount = rann->rann_hopcount;
 694         hopcount++;
 695         metric = rann->rann_metric;
 696         mhwmp_dbg("received RANN from %pM\n", orig_addr);
 697
 698         rcu_read_lock();
 699         mpath = mesh_path_lookup(orig_addr, sdata);
 700         if (!mpath) {
 701                 mesh_path_add(orig_addr, sdata);
 702                 mpath = mesh_path_lookup(orig_addr, sdata);
 703                 if (!mpath) {
 704                         rcu_read_unlock();
 705                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 706                         return;
 707                 }
 708                 mesh_queue_preq(mpath,
 709                                 PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 710         }
 711         if (mpath->sn < orig_sn) {
 712                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 713                                        cpu_to_le32(orig_sn),
 714                                        0, NULL, 0, broadcast_addr,
 715                                        hopcount, ttl, 0,
 716                                        cpu_to_le32(metric + mpath->metric),
 717                                        0, sdata);
 718                 mpath->sn = orig_sn;
 719         }
 720         rcu_read_unlock();
 721 }
 722
 723
 724 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 725                             struct ieee80211_mgmt *mgmt,
 726                             size_t len)
 727 {
 728         struct ieee802_11_elems elems;
 729         size_t baselen;
 730         u32 last_hop_metric;
 731
 732         /* need action_code */
 733         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 734                 return;
 735
 736         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 737         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 738                         len - baselen, &elems);
 739
 740         if (elems.preq) {
 741                 if (elems.preq_len != 37)
 742                         /* Right now we support just 1 destination and no AE */
 743                         return;
 744                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 745                                                       MPATH_PREQ);
 746                 if (last_hop_metric)
 747                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 748                                                 last_hop_metric);
 749         }
 750         if (elems.prep) {
 751                 if (elems.prep_len != 31)
 752                         /* Right now we support no AE */
 753                         return;
 754                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 755                                                       MPATH_PREP);
 756                 if (last_hop_metric)
 757                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 758                                                 last_hop_metric);
 759         }
 760         if (elems.perr) {
 761                 if (elems.perr_len != 15)
 762                         /* Right now we support only one destination per PERR */
 763                         return;
 764                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 765         }
 766         if (elems.rann)
 767                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 768 }
 769
 770 /**
 771  * mesh_queue_preq - queue a PREQ to a given destination
 772  *
 773  * @mpath: mesh path to discover
 774  * @flags: special attributes of the PREQ to be sent
 775  *
 776  * Locking: the function must be called from within a rcu read lock block.
 777  *
 778  */
 779 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 780 {
 781         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 782         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 783         struct mesh_preq_queue *preq_node;
 784
 785         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 786         if (!preq_node) {
 787                 mhwmp_dbg("could not allocate PREQ node\n");
 788                 return;
 789         }
 790
 791         spin_lock(&ifmsh->mesh_preq_queue_lock);
 792         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 793                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
 794                 kfree(preq_node);
 795                 if (printk_ratelimit())
 796                         mhwmp_dbg("PREQ node queue full\n");
 797                 return;
 798         }
 799
 800         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 801         preq_node->flags = flags;
 802
 803         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 804         ++ifmsh->preq_queue_len;
 805         spin_unlock(&ifmsh->mesh_preq_queue_lock);
 806
 807         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 808                 ieee80211_queue_work(&sdata->local->hw, &ifmsh->work);
 809
 810         else if (time_before(jiffies, ifmsh->last_preq)) {
 811                 /* avoid long wait if did not send preqs for a long time
 812                  * and jiffies wrapped around
 813                  */
 814                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 815                 ieee80211_queue_work(&sdata->local->hw, &ifmsh->work);
 816         } else
 817                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 818                                                 min_preq_int_jiff(sdata));
 819 }
 820
 821 /**
 822  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 823  *
 824  * @sdata: local mesh subif
 825  */
 826 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 827 {
 828         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 829         struct mesh_preq_queue *preq_node;
 830         struct mesh_path *mpath;
 831         u8 ttl, target_flags;
 832         u32 lifetime;
 833
 834         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 835         if (!ifmsh->preq_queue_len ||
 836                 time_before(jiffies, ifmsh->last_preq +
 837                                 min_preq_int_jiff(sdata))) {
 838                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 839                 return;
 840         }
 841
 842         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 843                         struct mesh_preq_queue, list);
 844         list_del(&preq_node->list);
 845         --ifmsh->preq_queue_len;
 846         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 847
 848         rcu_read_lock();
 849         mpath = mesh_path_lookup(preq_node->dst, sdata);
 850         if (!mpath)
 851                 goto enddiscovery;
 852
 853         spin_lock_bh(&mpath->state_lock);
 854         if (preq_node->flags & PREQ_Q_F_START) {
 855                 if (mpath->flags & MESH_PATH_RESOLVING) {
 856                         spin_unlock_bh(&mpath->state_lock);
 857                         goto enddiscovery;
 858                 } else {
 859                         mpath->flags &= ~MESH_PATH_RESOLVED;
 860                         mpath->flags |= MESH_PATH_RESOLVING;
 861                         mpath->discovery_retries = 0;
 862                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 863                 }
 864         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 865                         mpath->flags & MESH_PATH_RESOLVED) {
 866                 mpath->flags &= ~MESH_PATH_RESOLVING;
 867                 spin_unlock_bh(&mpath->state_lock);
 868                 goto enddiscovery;
 869         }
 870
 871         ifmsh->last_preq = jiffies;
 872
 873         if (time_after(jiffies, ifmsh->last_sn_update +
 874                                 net_traversal_jiffies(sdata)) ||
 875             time_before(jiffies, ifmsh->last_sn_update)) {
 876                 ++ifmsh->sn;
 877                 sdata->u.mesh.last_sn_update = jiffies;
 878         }
 879         lifetime = default_lifetime(sdata);
 880         ttl = sdata->u.mesh.mshcfg.dot11MeshTTL;
 881         if (ttl == 0) {
 882                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 883                 spin_unlock_bh(&mpath->state_lock);
 884                 goto enddiscovery;
 885         }
 886
 887         if (preq_node->flags & PREQ_Q_F_REFRESH)
 888                 target_flags = MP_F_DO;
 889         else
 890                 target_flags = MP_F_RF;
 891
 892         spin_unlock_bh(&mpath->state_lock);
 893         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
 894                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
 895                         cpu_to_le32(mpath->sn), broadcast_addr, 0,
 896                         ttl, cpu_to_le32(lifetime), 0,
 897                         cpu_to_le32(ifmsh->preq_id++), sdata);
 898         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 899
 900 enddiscovery:
 901         rcu_read_unlock();
 902         kfree(preq_node);
 903 }
 904
 905 /**
 906  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
 907  *
 908  * @skb: 802.11 frame to be sent
 909  * @sdata: network subif the frame will be sent through
 910  *
 911  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 912  * found, the function will start a path discovery and queue the frame so it is
 913  * sent when the path is resolved. This means the caller must not free the skb
 914  * in this case.
 915  */
 916 int mesh_nexthop_lookup(struct sk_buff *skb,
 917                         struct ieee80211_sub_if_data *sdata)
 918 {
 919         struct sk_buff *skb_to_free = NULL;
 920         struct mesh_path *mpath;
 921         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 922         u8 *target_addr = hdr->addr3;
 923         int err = 0;
 924
 925         rcu_read_lock();
 926         mpath = mesh_path_lookup(target_addr, sdata);
 927
 928         if (!mpath) {
 929                 mesh_path_add(target_addr, sdata);
 930                 mpath = mesh_path_lookup(target_addr, sdata);
 931                 if (!mpath) {
 932                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 933                         err = -ENOSPC;
 934                         goto endlookup;
 935                 }
 936         }
 937
 938         if (mpath->flags & MESH_PATH_ACTIVE) {
 939                 if (time_after(jiffies,
 940                                mpath->exp_time -
 941                                msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
 942                     !memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
 943                     !(mpath->flags & MESH_PATH_RESOLVING) &&
 944                     !(mpath->flags & MESH_PATH_FIXED)) {
 945                         mesh_queue_preq(mpath,
 946                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 947                 }
 948                 memcpy(hdr->addr1, mpath->next_hop->sta.addr, ETH_ALEN);
 949         } else {
 950                 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 951                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
 952                         /* Start discovery only if it is not running yet */
 953                         mesh_queue_preq(mpath, PREQ_Q_F_START);
 954                 }
 955
 956                 if (skb_queue_len(&mpath->frame_queue) >=
 957                                 MESH_FRAME_QUEUE_LEN)
 958                         skb_to_free = skb_dequeue(&mpath->frame_queue);
 959
 960                 info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 961                 skb_queue_tail(&mpath->frame_queue, skb);
 962                 if (skb_to_free)
 963                         mesh_path_discard_frame(skb_to_free, sdata);
 964                 err = -ENOENT;
 965         }
 966
 967 endlookup:
 968         rcu_read_unlock();
 969         return err;
 970 }
 971
 972 void mesh_path_timer(unsigned long data)
 973 {
 974         struct ieee80211_sub_if_data *sdata;
 975         struct mesh_path *mpath;
 976
 977         rcu_read_lock();
 978         mpath = (struct mesh_path *) data;
 979         mpath = rcu_dereference(mpath);
 980         if (!mpath)
 981                 goto endmpathtimer;
 982         sdata = mpath->sdata;
 983
 984         if (sdata->local->quiescing) {
 985                 rcu_read_unlock();
 986                 return;
 987         }
 988
 989         spin_lock_bh(&mpath->state_lock);
 990         if (mpath->flags & MESH_PATH_RESOLVED ||
 991                         (!(mpath->flags & MESH_PATH_RESOLVING)))
 992                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
 993         else if (mpath->discovery_retries < max_preq_retries(sdata)) {
 994                 ++mpath->discovery_retries;
 995                 mpath->discovery_timeout *= 2;
 996                 mesh_queue_preq(mpath, 0);
 997         } else {
 998                 mpath->flags = 0;
 999                 mpath->exp_time = jiffies;
1000                 mesh_path_flush_pending(mpath);
1001         }
1002
1003         spin_unlock_bh(&mpath->state_lock);
1004 endmpathtimer:
1005         rcu_read_unlock();
1006 }
1007
1008 void
1009 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1010 {
1011         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1012
1013         mesh_path_sel_frame_tx(MPATH_RANN, 0, sdata->vif.addr,
1014                                cpu_to_le32(++ifmsh->sn),
1015                                0, NULL, 0, broadcast_addr,
1016                                0, MESH_TTL, 0, 0, 0, sdata);
1017 }