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 <linux/slab.h>
  11 #include "mesh.h"
  12
  13 #ifdef CONFIG_MAC80211_VERBOSE_MHWMP_DEBUG
  14 #define mhwmp_dbg(fmt, args...)   printk(KERN_DEBUG "Mesh HWMP: " fmt, ##args)
  15 #else
  16 #define mhwmp_dbg(fmt, args...)   do { (void)(0); } while (0)
  17 #endif
  18
  19 #define TEST_FRAME_LEN  8192
  20 #define MAX_METRIC      0xffffffff
  21 #define ARITH_SHIFT     8
  22
  23 /* Number of frames buffered per destination for unresolved destinations */
  24 #define MESH_FRAME_QUEUE_LEN    10
  25 #define MAX_PREQ_QUEUE_LEN      64
  26
  27 /* Destination only */
  28 #define MP_F_DO 0x1
  29 /* Reply and forward */
  30 #define MP_F_RF 0x2
  31 /* Unknown Sequence Number */
  32 #define MP_F_USN    0x01
  33 /* Reason code Present */
  34 #define MP_F_RCODE  0x02
  35
  36 static void mesh_queue_preq(struct mesh_path *, u8);
  37
  38 static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
  39 {
  40         if (ae)
  41                 offset += 6;
  42         return get_unaligned_le32(preq_elem + offset);
  43 }
  44
  45 static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
  46 {
  47         if (ae)
  48                 offset += 6;
  49         return get_unaligned_le16(preq_elem + offset);
  50 }
  51
  52 /* HWMP IE processing macros */
  53 #define AE_F                    (1<<6)
  54 #define AE_F_SET(x)             (*x & AE_F)
  55 #define PREQ_IE_FLAGS(x)        (*(x))
  56 #define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  57 #define PREQ_IE_TTL(x)          (*(x + 2))
  58 #define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  59 #define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  60 #define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0);
  61 #define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x));
  62 #define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x));
  63 #define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  64 #define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  65 #define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x));
  66
  67
  68 #define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  69 #define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  70 #define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  71 #define PREP_IE_ORIG_ADDR(x)    (x + 3)
  72 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 9, 0);
  73 #define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x));
  74 #define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x));
  75 #define PREP_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 27 : x + 21)
  76 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 27, AE_F_SET(x));
  77
  78 #define PERR_IE_TTL(x)          (*(x))
  79 #define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  80 #define PERR_IE_TARGET_ADDR(x)  (x + 3)
  81 #define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0);
  82 #define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0);
  83
  84 #define MSEC_TO_TU(x) (x*1000/1024)
  85 #define SN_GT(x, y) ((long) (y) - (long) (x) < 0)
  86 #define SN_LT(x, y) ((long) (x) - (long) (y) < 0)
  87
  88 #define net_traversal_jiffies(s) \
  89         msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  90 #define default_lifetime(s) \
  91         MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  92 #define min_preq_int_jiff(s) \
  93         (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  94 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  95 #define disc_timeout_jiff(s) \
  96         msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  97
  98 enum mpath_frame_type {
  99         MPATH_PREQ = 0,
 100         MPATH_PREP,
 101         MPATH_PERR,
 102         MPATH_RANN
 103 };
 104
 105 static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 106
 107 static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 108                 u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
 109                 __le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
 110                 __le32 lifetime, __le32 metric, __le32 preq_id,
 111                 struct ieee80211_sub_if_data *sdata)
 112 {
 113         struct ieee80211_local *local = sdata->local;
 114         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
 115         struct ieee80211_mgmt *mgmt;
 116         u8 *pos;
 117         int ie_len;
 118
 119         if (!skb)
 120                 return -1;
 121         skb_reserve(skb, local->hw.extra_tx_headroom);
 122         /* 25 is the size of the common mgmt part (24) plus the size of the
 123          * common action part (1)
 124          */
 125         mgmt = (struct ieee80211_mgmt *)
 126                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 127         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 128         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 129                                           IEEE80211_STYPE_ACTION);
 130
 131         memcpy(mgmt->da, da, ETH_ALEN);
 132         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 133         /* BSSID == SA */
 134         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 135         mgmt->u.action.category = WLAN_CATEGORY_MESH_PATH_SEL;
 136         mgmt->u.action.u.mesh_action.action_code = MESH_PATH_SEL_ACTION;
 137
 138         switch (action) {
 139         case MPATH_PREQ:
 140                 mhwmp_dbg("sending PREQ to %pM\n", target);
 141                 ie_len = 37;
 142                 pos = skb_put(skb, 2 + ie_len);
 143                 *pos++ = WLAN_EID_PREQ;
 144                 break;
 145         case MPATH_PREP:
 146                 mhwmp_dbg("sending PREP to %pM\n", target);
 147                 ie_len = 31;
 148                 pos = skb_put(skb, 2 + ie_len);
 149                 *pos++ = WLAN_EID_PREP;
 150                 break;
 151         case MPATH_RANN:
 152                 mhwmp_dbg("sending RANN from %pM\n", orig_addr);
 153                 ie_len = sizeof(struct ieee80211_rann_ie);
 154                 pos = skb_put(skb, 2 + ie_len);
 155                 *pos++ = WLAN_EID_RANN;
 156                 break;
 157         default:
 158                 kfree_skb(skb);
 159                 return -ENOTSUPP;
 160                 break;
 161         }
 162         *pos++ = ie_len;
 163         *pos++ = flags;
 164         *pos++ = hop_count;
 165         *pos++ = ttl;
 166         if (action == MPATH_PREQ) {
 167                 memcpy(pos, &preq_id, 4);
 168                 pos += 4;
 169         }
 170         memcpy(pos, orig_addr, ETH_ALEN);
 171         pos += ETH_ALEN;
 172         memcpy(pos, &orig_sn, 4);
 173         pos += 4;
 174         if (action != MPATH_RANN) {
 175                 memcpy(pos, &lifetime, 4);
 176                 pos += 4;
 177         }
 178         memcpy(pos, &metric, 4);
 179         pos += 4;
 180         if (action == MPATH_PREQ) {
 181                 /* destination count */
 182                 *pos++ = 1;
 183                 *pos++ = target_flags;
 184         }
 185         if (action != MPATH_RANN) {
 186                 memcpy(pos, target, ETH_ALEN);
 187                 pos += ETH_ALEN;
 188                 memcpy(pos, &target_sn, 4);
 189         }
 190
 191         ieee80211_tx_skb(sdata, skb);
 192         return 0;
 193 }
 194
 195 /**
 196  * mesh_send_path error - Sends a PERR mesh management frame
 197  *
 198  * @target: broken destination
 199  * @target_sn: SN of the broken destination
 200  * @target_rcode: reason code for this PERR
 201  * @ra: node this frame is addressed to
 202  */
 203 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 204                        __le16 target_rcode, const u8 *ra,
 205                        struct ieee80211_sub_if_data *sdata)
 206 {
 207         struct ieee80211_local *local = sdata->local;
 208         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
 209         struct ieee80211_mgmt *mgmt;
 210         u8 *pos;
 211         int ie_len;
 212
 213         if (!skb)
 214                 return -1;
 215         skb_reserve(skb, local->hw.extra_tx_headroom);
 216         /* 25 is the size of the common mgmt part (24) plus the size of the
 217          * common action part (1)
 218          */
 219         mgmt = (struct ieee80211_mgmt *)
 220                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 221         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 222         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 223                                           IEEE80211_STYPE_ACTION);
 224
 225         memcpy(mgmt->da, ra, ETH_ALEN);
 226         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 227         /* BSSID is left zeroed, wildcard value */
 228         mgmt->u.action.category = WLAN_CATEGORY_MESH_PATH_SEL;
 229         mgmt->u.action.u.mesh_action.action_code = MESH_PATH_SEL_ACTION;
 230         ie_len = 15;
 231         pos = skb_put(skb, 2 + ie_len);
 232         *pos++ = WLAN_EID_PERR;
 233         *pos++ = ie_len;
 234         /* ttl */
 235         *pos++ = ttl;
 236         /* number of destinations */
 237         *pos++ = 1;
 238         /*
 239          * flags bit, bit 1 is unset if we know the sequence number and
 240          * bit 2 is set if we have a reason code
 241          */
 242         *pos = 0;
 243         if (!target_sn)
 244                 *pos |= MP_F_USN;
 245         if (target_rcode)
 246                 *pos |= MP_F_RCODE;
 247         pos++;
 248         memcpy(pos, target, ETH_ALEN);
 249         pos += ETH_ALEN;
 250         memcpy(pos, &target_sn, 4);
 251         pos += 4;
 252         memcpy(pos, &target_rcode, 2);
 253
 254         ieee80211_tx_skb(sdata, skb);
 255         return 0;
 256 }
 257
 258 void ieee80211s_update_metric(struct ieee80211_local *local,
 259                 struct sta_info *stainfo, struct sk_buff *skb)
 260 {
 261         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 262         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 263         int failed;
 264
 265         if (!ieee80211_is_data(hdr->frame_control))
 266                 return;
 267
 268         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 269
 270         /* moving average, scaled to 100 */
 271         stainfo->fail_avg = ((80 * stainfo->fail_avg + 5) / 100 + 20 * failed);
 272         if (stainfo->fail_avg > 95)
 273                 mesh_plink_broken(stainfo);
 274 }
 275
 276 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 277                                    struct sta_info *sta)
 278 {
 279         struct ieee80211_supported_band *sband;
 280         /* This should be adjusted for each device */
 281         int device_constant = 1 << ARITH_SHIFT;
 282         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 283         int s_unit = 1 << ARITH_SHIFT;
 284         int rate, err;
 285         u32 tx_time, estimated_retx;
 286         u64 result;
 287
 288         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 289
 290         if (sta->fail_avg >= 100)
 291                 return MAX_METRIC;
 292
 293         if (sta->last_tx_rate.flags & IEEE80211_TX_RC_MCS)
 294                 return MAX_METRIC;
 295
 296         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 297
 298         /* bitrate is in units of 100 Kbps, while we need rate in units of
 299          * 1Mbps. This will be corrected on tx_time computation.
 300          */
 301         rate = sband->bitrates[sta->last_tx_rate.idx].bitrate;
 302         tx_time = (device_constant + 10 * test_frame_len / rate);
 303         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 304         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 305         return (u32)result;
 306 }
 307
 308 /**
 309  * hwmp_route_info_get - Update routing info to originator and transmitter
 310  *
 311  * @sdata: local mesh subif
 312  * @mgmt: mesh management frame
 313  * @hwmp_ie: hwmp information element (PREP or PREQ)
 314  *
 315  * This function updates the path routing information to the originator and the
 316  * transmitter of a HWMP PREQ or PREP frame.
 317  *
 318  * Returns: metric to frame originator or 0 if the frame should not be further
 319  * processed
 320  *
 321  * Notes: this function is the only place (besides user-provided info) where
 322  * path routing information is updated.
 323  */
 324 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 325                             struct ieee80211_mgmt *mgmt,
 326                             u8 *hwmp_ie, enum mpath_frame_type action)
 327 {
 328         struct ieee80211_local *local = sdata->local;
 329         struct mesh_path *mpath;
 330         struct sta_info *sta;
 331         bool fresh_info;
 332         u8 *orig_addr, *ta;
 333         u32 orig_sn, orig_metric;
 334         unsigned long orig_lifetime, exp_time;
 335         u32 last_hop_metric, new_metric;
 336         bool process = true;
 337
 338         rcu_read_lock();
 339         sta = sta_info_get(sdata, mgmt->sa);
 340         if (!sta) {
 341                 rcu_read_unlock();
 342                 return 0;
 343         }
 344
 345         last_hop_metric = airtime_link_metric_get(local, sta);
 346         /* Update and check originator routing info */
 347         fresh_info = true;
 348
 349         switch (action) {
 350         case MPATH_PREQ:
 351                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 352                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 353                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 354                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 355                 break;
 356         case MPATH_PREP:
 357                 /* Originator here refers to the MP that was the destination in
 358                  * the Path Request. The draft refers to that MP as the
 359                  * destination address, even though usually it is the origin of
 360                  * the PREP frame. We divert from the nomenclature in the draft
 361                  * so that we can easily use a single function to gather path
 362                  * information from both PREQ and PREP frames.
 363                  */
 364                 orig_addr = PREP_IE_ORIG_ADDR(hwmp_ie);
 365                 orig_sn = PREP_IE_ORIG_SN(hwmp_ie);
 366                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 367                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 368                 break;
 369         default:
 370                 rcu_read_unlock();
 371                 return 0;
 372         }
 373         new_metric = orig_metric + last_hop_metric;
 374         if (new_metric < orig_metric)
 375                 new_metric = MAX_METRIC;
 376         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 377
 378         if (memcmp(orig_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 379                 /* This MP is the originator, we are not interested in this
 380                  * frame, except for updating transmitter's path info.
 381                  */
 382                 process = false;
 383                 fresh_info = false;
 384         } else {
 385                 mpath = mesh_path_lookup(orig_addr, sdata);
 386                 if (mpath) {
 387                         spin_lock_bh(&mpath->state_lock);
 388                         if (mpath->flags & MESH_PATH_FIXED)
 389                                 fresh_info = false;
 390                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 391                             (mpath->flags & MESH_PATH_SN_VALID)) {
 392                                 if (SN_GT(mpath->sn, orig_sn) ||
 393                                     (mpath->sn == orig_sn &&
 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.element_ttl;
 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 inline struct sta_info *
 564 next_hop_deref_protected(struct mesh_path *mpath)
 565 {
 566         return rcu_dereference_protected(mpath->next_hop,
 567                                          lockdep_is_held(&mpath->state_lock));
 568 }
 569
 570
 571 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 572                                     struct ieee80211_mgmt *mgmt,
 573                                     u8 *prep_elem, u32 metric)
 574 {
 575         struct mesh_path *mpath;
 576         u8 *target_addr, *orig_addr;
 577         u8 ttl, hopcount, flags;
 578         u8 next_hop[ETH_ALEN];
 579         u32 target_sn, orig_sn, lifetime;
 580
 581         mhwmp_dbg("received PREP from %pM\n", PREP_IE_ORIG_ADDR(prep_elem));
 582
 583         /* Note that we divert from the draft nomenclature and denominate
 584          * destination to what the draft refers to as origininator. So in this
 585          * function destnation refers to the final destination of the PREP,
 586          * which corresponds with the originator of the PREQ which this PREP
 587          * replies
 588          */
 589         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 590         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0)
 591                 /* destination, no forwarding required */
 592                 return;
 593
 594         ttl = PREP_IE_TTL(prep_elem);
 595         if (ttl <= 1) {
 596                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 597                 return;
 598         }
 599
 600         rcu_read_lock();
 601         mpath = mesh_path_lookup(target_addr, sdata);
 602         if (mpath)
 603                 spin_lock_bh(&mpath->state_lock);
 604         else
 605                 goto fail;
 606         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 607                 spin_unlock_bh(&mpath->state_lock);
 608                 goto fail;
 609         }
 610         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 611         spin_unlock_bh(&mpath->state_lock);
 612         --ttl;
 613         flags = PREP_IE_FLAGS(prep_elem);
 614         lifetime = PREP_IE_LIFETIME(prep_elem);
 615         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 616         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 617         target_sn = PREP_IE_TARGET_SN(prep_elem);
 618         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 619
 620         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 621                 cpu_to_le32(orig_sn), 0, target_addr,
 622                 cpu_to_le32(target_sn), next_hop, hopcount,
 623                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 624                 0, sdata);
 625         rcu_read_unlock();
 626
 627         sdata->u.mesh.mshstats.fwded_unicast++;
 628         sdata->u.mesh.mshstats.fwded_frames++;
 629         return;
 630
 631 fail:
 632         rcu_read_unlock();
 633         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 634 }
 635
 636 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 637                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 638 {
 639         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 640         struct mesh_path *mpath;
 641         u8 ttl;
 642         u8 *ta, *target_addr;
 643         u32 target_sn;
 644         u16 target_rcode;
 645
 646         ta = mgmt->sa;
 647         ttl = PERR_IE_TTL(perr_elem);
 648         if (ttl <= 1) {
 649                 ifmsh->mshstats.dropped_frames_ttl++;
 650                 return;
 651         }
 652         ttl--;
 653         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 654         target_sn = PERR_IE_TARGET_SN(perr_elem);
 655         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 656
 657         rcu_read_lock();
 658         mpath = mesh_path_lookup(target_addr, sdata);
 659         if (mpath) {
 660                 spin_lock_bh(&mpath->state_lock);
 661                 if (mpath->flags & MESH_PATH_ACTIVE &&
 662                     memcmp(ta, next_hop_deref_protected(mpath)->sta.addr,
 663                                                         ETH_ALEN) == 0 &&
 664                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 665                     SN_GT(target_sn, mpath->sn))) {
 666                         mpath->flags &= ~MESH_PATH_ACTIVE;
 667                         mpath->sn = target_sn;
 668                         spin_unlock_bh(&mpath->state_lock);
 669                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 670                                            cpu_to_le16(target_rcode),
 671                                            broadcast_addr, sdata);
 672                 } else
 673                         spin_unlock_bh(&mpath->state_lock);
 674         }
 675         rcu_read_unlock();
 676 }
 677
 678 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 679                                 struct ieee80211_mgmt *mgmt,
 680                                 struct ieee80211_rann_ie *rann)
 681 {
 682         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 683         struct mesh_path *mpath;
 684         u8 ttl, flags, hopcount;
 685         u8 *orig_addr;
 686         u32 orig_sn, metric;
 687
 688         ttl = rann->rann_ttl;
 689         if (ttl <= 1) {
 690                 ifmsh->mshstats.dropped_frames_ttl++;
 691                 return;
 692         }
 693         ttl--;
 694         flags = rann->rann_flags;
 695         orig_addr = rann->rann_addr;
 696         orig_sn = rann->rann_seq;
 697         hopcount = rann->rann_hopcount;
 698         hopcount++;
 699         metric = rann->rann_metric;
 700         mhwmp_dbg("received RANN from %pM\n", orig_addr);
 701
 702         rcu_read_lock();
 703         mpath = mesh_path_lookup(orig_addr, sdata);
 704         if (!mpath) {
 705                 mesh_path_add(orig_addr, sdata);
 706                 mpath = mesh_path_lookup(orig_addr, sdata);
 707                 if (!mpath) {
 708                         rcu_read_unlock();
 709                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 710                         return;
 711                 }
 712                 mesh_queue_preq(mpath,
 713                                 PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 714         }
 715         if (mpath->sn < orig_sn) {
 716                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 717                                        cpu_to_le32(orig_sn),
 718                                        0, NULL, 0, broadcast_addr,
 719                                        hopcount, ttl, 0,
 720                                        cpu_to_le32(metric + mpath->metric),
 721                                        0, sdata);
 722                 mpath->sn = orig_sn;
 723         }
 724         rcu_read_unlock();
 725 }
 726
 727
 728 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 729                             struct ieee80211_mgmt *mgmt,
 730                             size_t len)
 731 {
 732         struct ieee802_11_elems elems;
 733         size_t baselen;
 734         u32 last_hop_metric;
 735
 736         /* need action_code */
 737         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 738                 return;
 739
 740         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 741         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 742                         len - baselen, &elems);
 743
 744         if (elems.preq) {
 745                 if (elems.preq_len != 37)
 746                         /* Right now we support just 1 destination and no AE */
 747                         return;
 748                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 749                                                       MPATH_PREQ);
 750                 if (last_hop_metric)
 751                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 752                                                 last_hop_metric);
 753         }
 754         if (elems.prep) {
 755                 if (elems.prep_len != 31)
 756                         /* Right now we support no AE */
 757                         return;
 758                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 759                                                       MPATH_PREP);
 760                 if (last_hop_metric)
 761                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 762                                                 last_hop_metric);
 763         }
 764         if (elems.perr) {
 765                 if (elems.perr_len != 15)
 766                         /* Right now we support only one destination per PERR */
 767                         return;
 768                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 769         }
 770         if (elems.rann)
 771                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 772 }
 773
 774 /**
 775  * mesh_queue_preq - queue a PREQ to a given destination
 776  *
 777  * @mpath: mesh path to discover
 778  * @flags: special attributes of the PREQ to be sent
 779  *
 780  * Locking: the function must be called from within a rcu read lock block.
 781  *
 782  */
 783 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 784 {
 785         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 786         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 787         struct mesh_preq_queue *preq_node;
 788
 789         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 790         if (!preq_node) {
 791                 mhwmp_dbg("could not allocate PREQ node\n");
 792                 return;
 793         }
 794
 795         spin_lock(&ifmsh->mesh_preq_queue_lock);
 796         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 797                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
 798                 kfree(preq_node);
 799                 if (printk_ratelimit())
 800                         mhwmp_dbg("PREQ node queue full\n");
 801                 return;
 802         }
 803
 804         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 805         preq_node->flags = flags;
 806
 807         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 808         ++ifmsh->preq_queue_len;
 809         spin_unlock(&ifmsh->mesh_preq_queue_lock);
 810
 811         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 812                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 813
 814         else if (time_before(jiffies, ifmsh->last_preq)) {
 815                 /* avoid long wait if did not send preqs for a long time
 816                  * and jiffies wrapped around
 817                  */
 818                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 819                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 820         } else
 821                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 822                                                 min_preq_int_jiff(sdata));
 823 }
 824
 825 /**
 826  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 827  *
 828  * @sdata: local mesh subif
 829  */
 830 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 831 {
 832         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 833         struct mesh_preq_queue *preq_node;
 834         struct mesh_path *mpath;
 835         u8 ttl, target_flags;
 836         u32 lifetime;
 837
 838         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 839         if (!ifmsh->preq_queue_len ||
 840                 time_before(jiffies, ifmsh->last_preq +
 841                                 min_preq_int_jiff(sdata))) {
 842                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 843                 return;
 844         }
 845
 846         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 847                         struct mesh_preq_queue, list);
 848         list_del(&preq_node->list);
 849         --ifmsh->preq_queue_len;
 850         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 851
 852         rcu_read_lock();
 853         mpath = mesh_path_lookup(preq_node->dst, sdata);
 854         if (!mpath)
 855                 goto enddiscovery;
 856
 857         spin_lock_bh(&mpath->state_lock);
 858         if (preq_node->flags & PREQ_Q_F_START) {
 859                 if (mpath->flags & MESH_PATH_RESOLVING) {
 860                         spin_unlock_bh(&mpath->state_lock);
 861                         goto enddiscovery;
 862                 } else {
 863                         mpath->flags &= ~MESH_PATH_RESOLVED;
 864                         mpath->flags |= MESH_PATH_RESOLVING;
 865                         mpath->discovery_retries = 0;
 866                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 867                 }
 868         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 869                         mpath->flags & MESH_PATH_RESOLVED) {
 870                 mpath->flags &= ~MESH_PATH_RESOLVING;
 871                 spin_unlock_bh(&mpath->state_lock);
 872                 goto enddiscovery;
 873         }
 874
 875         ifmsh->last_preq = jiffies;
 876
 877         if (time_after(jiffies, ifmsh->last_sn_update +
 878                                 net_traversal_jiffies(sdata)) ||
 879             time_before(jiffies, ifmsh->last_sn_update)) {
 880                 ++ifmsh->sn;
 881                 sdata->u.mesh.last_sn_update = jiffies;
 882         }
 883         lifetime = default_lifetime(sdata);
 884         ttl = sdata->u.mesh.mshcfg.element_ttl;
 885         if (ttl == 0) {
 886                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 887                 spin_unlock_bh(&mpath->state_lock);
 888                 goto enddiscovery;
 889         }
 890
 891         if (preq_node->flags & PREQ_Q_F_REFRESH)
 892                 target_flags = MP_F_DO;
 893         else
 894                 target_flags = MP_F_RF;
 895
 896         spin_unlock_bh(&mpath->state_lock);
 897         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
 898                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
 899                         cpu_to_le32(mpath->sn), broadcast_addr, 0,
 900                         ttl, cpu_to_le32(lifetime), 0,
 901                         cpu_to_le32(ifmsh->preq_id++), sdata);
 902         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 903
 904 enddiscovery:
 905         rcu_read_unlock();
 906         kfree(preq_node);
 907 }
 908
 909 /**
 910  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
 911  *
 912  * @skb: 802.11 frame to be sent
 913  * @sdata: network subif the frame will be sent through
 914  *
 915  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 916  * found, the function will start a path discovery and queue the frame so it is
 917  * sent when the path is resolved. This means the caller must not free the skb
 918  * in this case.
 919  */
 920 int mesh_nexthop_lookup(struct sk_buff *skb,
 921                         struct ieee80211_sub_if_data *sdata)
 922 {
 923         struct sk_buff *skb_to_free = NULL;
 924         struct mesh_path *mpath;
 925         struct sta_info *next_hop;
 926         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 927         u8 *target_addr = hdr->addr3;
 928         int err = 0;
 929
 930         rcu_read_lock();
 931         mpath = mesh_path_lookup(target_addr, sdata);
 932
 933         if (!mpath) {
 934                 mesh_path_add(target_addr, sdata);
 935                 mpath = mesh_path_lookup(target_addr, sdata);
 936                 if (!mpath) {
 937                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 938                         err = -ENOSPC;
 939                         goto endlookup;
 940                 }
 941         }
 942
 943         if (mpath->flags & MESH_PATH_ACTIVE) {
 944                 if (time_after(jiffies,
 945                                mpath->exp_time -
 946                                msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
 947                     !memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
 948                     !(mpath->flags & MESH_PATH_RESOLVING) &&
 949                     !(mpath->flags & MESH_PATH_FIXED)) {
 950                         mesh_queue_preq(mpath,
 951                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 952                 }
 953                 next_hop = rcu_dereference(mpath->next_hop);
 954                 if (next_hop)
 955                         memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
 956                 else
 957                         err = -ENOENT;
 958         } else {
 959                 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 960                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
 961                         /* Start discovery only if it is not running yet */
 962                         mesh_queue_preq(mpath, PREQ_Q_F_START);
 963                 }
 964
 965                 if (skb_queue_len(&mpath->frame_queue) >=
 966                                 MESH_FRAME_QUEUE_LEN)
 967                         skb_to_free = skb_dequeue(&mpath->frame_queue);
 968
 969                 info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 970                 skb_queue_tail(&mpath->frame_queue, skb);
 971                 if (skb_to_free)
 972                         mesh_path_discard_frame(skb_to_free, sdata);
 973                 err = -ENOENT;
 974         }
 975
 976 endlookup:
 977         rcu_read_unlock();
 978         return err;
 979 }
 980
 981 void mesh_path_timer(unsigned long data)
 982 {
 983         struct mesh_path *mpath = (void *) data;
 984         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 985
 986         if (sdata->local->quiescing)
 987                 return;
 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 }
1005
1006 void
1007 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1008 {
1009         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1010
1011         mesh_path_sel_frame_tx(MPATH_RANN, 0, sdata->vif.addr,
1012                                cpu_to_le32(++ifmsh->sn),
1013                                0, NULL, 0, broadcast_addr,
1014                                0, sdata->u.mesh.mshcfg.element_ttl,
1015                                0, 0, 0, sdata);
1016 }