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