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)    (AE_F_SET(x) ? x + 27 : x + 21)
  72 #define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  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)  (x + 3)
  76 #define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  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_ACTION;
 136         mgmt->u.action.u.mesh_action.action_code =
 137                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 138
 139         switch (action) {
 140         case MPATH_PREQ:
 141                 mhwmp_dbg("sending PREQ to %pM\n", target);
 142                 ie_len = 37;
 143                 pos = skb_put(skb, 2 + ie_len);
 144                 *pos++ = WLAN_EID_PREQ;
 145                 break;
 146         case MPATH_PREP:
 147                 mhwmp_dbg("sending PREP to %pM\n", target);
 148                 ie_len = 31;
 149                 pos = skb_put(skb, 2 + ie_len);
 150                 *pos++ = WLAN_EID_PREP;
 151                 break;
 152         case MPATH_RANN:
 153                 mhwmp_dbg("sending RANN from %pM\n", orig_addr);
 154                 ie_len = sizeof(struct ieee80211_rann_ie);
 155                 pos = skb_put(skb, 2 + ie_len);
 156                 *pos++ = WLAN_EID_RANN;
 157                 break;
 158         default:
 159                 kfree_skb(skb);
 160                 return -ENOTSUPP;
 161                 break;
 162         }
 163         *pos++ = ie_len;
 164         *pos++ = flags;
 165         *pos++ = hop_count;
 166         *pos++ = ttl;
 167         if (action == MPATH_PREP) {
 168                 memcpy(pos, target, ETH_ALEN);
 169                 pos += ETH_ALEN;
 170                 memcpy(pos, &target_sn, 4);
 171                 pos += 4;
 172         } else {
 173                 if (action == MPATH_PREQ) {
 174                         memcpy(pos, &preq_id, 4);
 175                         pos += 4;
 176                 }
 177                 memcpy(pos, orig_addr, ETH_ALEN);
 178                 pos += ETH_ALEN;
 179                 memcpy(pos, &orig_sn, 4);
 180                 pos += 4;
 181         }
 182         memcpy(pos, &lifetime, 4);      /* interval for RANN */
 183         pos += 4;
 184         memcpy(pos, &metric, 4);
 185         pos += 4;
 186         if (action == MPATH_PREQ) {
 187                 *pos++ = 1; /* destination count */
 188                 *pos++ = target_flags;
 189                 memcpy(pos, target, ETH_ALEN);
 190                 pos += ETH_ALEN;
 191                 memcpy(pos, &target_sn, 4);
 192                 pos += 4;
 193         } else if (action == MPATH_PREP) {
 194                 memcpy(pos, orig_addr, ETH_ALEN);
 195                 pos += ETH_ALEN;
 196                 memcpy(pos, &orig_sn, 4);
 197                 pos += 4;
 198         }
 199
 200         ieee80211_tx_skb(sdata, skb);
 201         return 0;
 202 }
 203
 204 /**
 205  * mesh_send_path error - Sends a PERR mesh management frame
 206  *
 207  * @target: broken destination
 208  * @target_sn: SN of the broken destination
 209  * @target_rcode: reason code for this PERR
 210  * @ra: node this frame is addressed to
 211  */
 212 int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 213                        __le16 target_rcode, const u8 *ra,
 214                        struct ieee80211_sub_if_data *sdata)
 215 {
 216         struct ieee80211_local *local = sdata->local;
 217         struct sk_buff *skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
 218         struct ieee80211_mgmt *mgmt;
 219         u8 *pos;
 220         int ie_len;
 221
 222         if (!skb)
 223                 return -1;
 224         skb_reserve(skb, local->hw.extra_tx_headroom);
 225         /* 25 is the size of the common mgmt part (24) plus the size of the
 226          * common action part (1)
 227          */
 228         mgmt = (struct ieee80211_mgmt *)
 229                 skb_put(skb, 25 + sizeof(mgmt->u.action.u.mesh_action));
 230         memset(mgmt, 0, 25 + sizeof(mgmt->u.action.u.mesh_action));
 231         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 232                                           IEEE80211_STYPE_ACTION);
 233
 234         memcpy(mgmt->da, ra, ETH_ALEN);
 235         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 236         /* BSSID == SA */
 237         memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 238         mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 239         mgmt->u.action.u.mesh_action.action_code =
 240                                         WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 241         ie_len = 15;
 242         pos = skb_put(skb, 2 + ie_len);
 243         *pos++ = WLAN_EID_PERR;
 244         *pos++ = ie_len;
 245         /* ttl */
 246         *pos++ = ttl;
 247         /* number of destinations */
 248         *pos++ = 1;
 249         /*
 250          * flags bit, bit 1 is unset if we know the sequence number and
 251          * bit 2 is set if we have a reason code
 252          */
 253         *pos = 0;
 254         if (!target_sn)
 255                 *pos |= MP_F_USN;
 256         if (target_rcode)
 257                 *pos |= MP_F_RCODE;
 258         pos++;
 259         memcpy(pos, target, ETH_ALEN);
 260         pos += ETH_ALEN;
 261         memcpy(pos, &target_sn, 4);
 262         pos += 4;
 263         memcpy(pos, &target_rcode, 2);
 264
 265         ieee80211_tx_skb(sdata, skb);
 266         return 0;
 267 }
 268
 269 void ieee80211s_update_metric(struct ieee80211_local *local,
 270                 struct sta_info *stainfo, struct sk_buff *skb)
 271 {
 272         struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 273         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 274         int failed;
 275
 276         if (!ieee80211_is_data(hdr->frame_control))
 277                 return;
 278
 279         failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 280
 281         /* moving average, scaled to 100 */
 282         stainfo->fail_avg = ((80 * stainfo->fail_avg + 5) / 100 + 20 * failed);
 283         if (stainfo->fail_avg > 95)
 284                 mesh_plink_broken(stainfo);
 285 }
 286
 287 static u32 airtime_link_metric_get(struct ieee80211_local *local,
 288                                    struct sta_info *sta)
 289 {
 290         struct ieee80211_supported_band *sband;
 291         /* This should be adjusted for each device */
 292         int device_constant = 1 << ARITH_SHIFT;
 293         int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 294         int s_unit = 1 << ARITH_SHIFT;
 295         int rate, err;
 296         u32 tx_time, estimated_retx;
 297         u64 result;
 298
 299         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 300
 301         if (sta->fail_avg >= 100)
 302                 return MAX_METRIC;
 303
 304         if (sta->last_tx_rate.flags & IEEE80211_TX_RC_MCS)
 305                 return MAX_METRIC;
 306
 307         err = (sta->fail_avg << ARITH_SHIFT) / 100;
 308
 309         /* bitrate is in units of 100 Kbps, while we need rate in units of
 310          * 1Mbps. This will be corrected on tx_time computation.
 311          */
 312         rate = sband->bitrates[sta->last_tx_rate.idx].bitrate;
 313         tx_time = (device_constant + 10 * test_frame_len / rate);
 314         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 315         result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 316         return (u32)result;
 317 }
 318
 319 /**
 320  * hwmp_route_info_get - Update routing info to originator and transmitter
 321  *
 322  * @sdata: local mesh subif
 323  * @mgmt: mesh management frame
 324  * @hwmp_ie: hwmp information element (PREP or PREQ)
 325  *
 326  * This function updates the path routing information to the originator and the
 327  * transmitter of a HWMP PREQ or PREP frame.
 328  *
 329  * Returns: metric to frame originator or 0 if the frame should not be further
 330  * processed
 331  *
 332  * Notes: this function is the only place (besides user-provided info) where
 333  * path routing information is updated.
 334  */
 335 static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 336                             struct ieee80211_mgmt *mgmt,
 337                             u8 *hwmp_ie, enum mpath_frame_type action)
 338 {
 339         struct ieee80211_local *local = sdata->local;
 340         struct mesh_path *mpath;
 341         struct sta_info *sta;
 342         bool fresh_info;
 343         u8 *orig_addr, *ta;
 344         u32 orig_sn, orig_metric;
 345         unsigned long orig_lifetime, exp_time;
 346         u32 last_hop_metric, new_metric;
 347         bool process = true;
 348
 349         rcu_read_lock();
 350         sta = sta_info_get(sdata, mgmt->sa);
 351         if (!sta) {
 352                 rcu_read_unlock();
 353                 return 0;
 354         }
 355
 356         last_hop_metric = airtime_link_metric_get(local, sta);
 357         /* Update and check originator routing info */
 358         fresh_info = true;
 359
 360         switch (action) {
 361         case MPATH_PREQ:
 362                 orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 363                 orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 364                 orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 365                 orig_metric = PREQ_IE_METRIC(hwmp_ie);
 366                 break;
 367         case MPATH_PREP:
 368                 /* Originator here refers to the MP that was the destination in
 369                  * the Path Request. The draft refers to that MP as the
 370                  * destination address, even though usually it is the origin of
 371                  * the PREP frame. We divert from the nomenclature in the draft
 372                  * so that we can easily use a single function to gather path
 373                  * information from both PREQ and PREP frames.
 374                  */
 375                 orig_addr = PREP_IE_ORIG_ADDR(hwmp_ie);
 376                 orig_sn = PREP_IE_ORIG_SN(hwmp_ie);
 377                 orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 378                 orig_metric = PREP_IE_METRIC(hwmp_ie);
 379                 break;
 380         default:
 381                 rcu_read_unlock();
 382                 return 0;
 383         }
 384         new_metric = orig_metric + last_hop_metric;
 385         if (new_metric < orig_metric)
 386                 new_metric = MAX_METRIC;
 387         exp_time = TU_TO_EXP_TIME(orig_lifetime);
 388
 389         if (memcmp(orig_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 390                 /* This MP is the originator, we are not interested in this
 391                  * frame, except for updating transmitter's path info.
 392                  */
 393                 process = false;
 394                 fresh_info = false;
 395         } else {
 396                 mpath = mesh_path_lookup(orig_addr, sdata);
 397                 if (mpath) {
 398                         spin_lock_bh(&mpath->state_lock);
 399                         if (mpath->flags & MESH_PATH_FIXED)
 400                                 fresh_info = false;
 401                         else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 402                             (mpath->flags & MESH_PATH_SN_VALID)) {
 403                                 if (SN_GT(mpath->sn, orig_sn) ||
 404                                     (mpath->sn == orig_sn &&
 405                                      new_metric >= mpath->metric)) {
 406                                         process = false;
 407                                         fresh_info = false;
 408                                 }
 409                         }
 410                 } else {
 411                         mesh_path_add(orig_addr, sdata);
 412                         mpath = mesh_path_lookup(orig_addr, sdata);
 413                         if (!mpath) {
 414                                 rcu_read_unlock();
 415                                 return 0;
 416                         }
 417                         spin_lock_bh(&mpath->state_lock);
 418                 }
 419
 420                 if (fresh_info) {
 421                         mesh_path_assign_nexthop(mpath, sta);
 422                         mpath->flags |= MESH_PATH_SN_VALID;
 423                         mpath->metric = new_metric;
 424                         mpath->sn = orig_sn;
 425                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 426                                           ?  mpath->exp_time : exp_time;
 427                         mesh_path_activate(mpath);
 428                         spin_unlock_bh(&mpath->state_lock);
 429                         mesh_path_tx_pending(mpath);
 430                         /* draft says preq_id should be saved to, but there does
 431                          * not seem to be any use for it, skipping by now
 432                          */
 433                 } else
 434                         spin_unlock_bh(&mpath->state_lock);
 435         }
 436
 437         /* Update and check transmitter routing info */
 438         ta = mgmt->sa;
 439         if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
 440                 fresh_info = false;
 441         else {
 442                 fresh_info = true;
 443
 444                 mpath = mesh_path_lookup(ta, sdata);
 445                 if (mpath) {
 446                         spin_lock_bh(&mpath->state_lock);
 447                         if ((mpath->flags & MESH_PATH_FIXED) ||
 448                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 449                                         (last_hop_metric > mpath->metric)))
 450                                 fresh_info = false;
 451                 } else {
 452                         mesh_path_add(ta, sdata);
 453                         mpath = mesh_path_lookup(ta, sdata);
 454                         if (!mpath) {
 455                                 rcu_read_unlock();
 456                                 return 0;
 457                         }
 458                         spin_lock_bh(&mpath->state_lock);
 459                 }
 460
 461                 if (fresh_info) {
 462                         mesh_path_assign_nexthop(mpath, sta);
 463                         mpath->metric = last_hop_metric;
 464                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 465                                           ?  mpath->exp_time : exp_time;
 466                         mesh_path_activate(mpath);
 467                         spin_unlock_bh(&mpath->state_lock);
 468                         mesh_path_tx_pending(mpath);
 469                 } else
 470                         spin_unlock_bh(&mpath->state_lock);
 471         }
 472
 473         rcu_read_unlock();
 474
 475         return process ? new_metric : 0;
 476 }
 477
 478 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 479                                     struct ieee80211_mgmt *mgmt,
 480                                     u8 *preq_elem, u32 metric)
 481 {
 482         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 483         struct mesh_path *mpath;
 484         u8 *target_addr, *orig_addr;
 485         u8 target_flags, ttl;
 486         u32 orig_sn, target_sn, lifetime;
 487         bool reply = false;
 488         bool forward = true;
 489
 490         /* Update target SN, if present */
 491         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 492         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 493         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 494         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 495         target_flags = PREQ_IE_TARGET_F(preq_elem);
 496
 497         mhwmp_dbg("received PREQ from %pM\n", orig_addr);
 498
 499         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 500                 mhwmp_dbg("PREQ is for us\n");
 501                 forward = false;
 502                 reply = true;
 503                 metric = 0;
 504                 if (time_after(jiffies, ifmsh->last_sn_update +
 505                                         net_traversal_jiffies(sdata)) ||
 506                     time_before(jiffies, ifmsh->last_sn_update)) {
 507                         target_sn = ++ifmsh->sn;
 508                         ifmsh->last_sn_update = jiffies;
 509                 }
 510         } else {
 511                 rcu_read_lock();
 512                 mpath = mesh_path_lookup(target_addr, sdata);
 513                 if (mpath) {
 514                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 515                                         SN_LT(mpath->sn, target_sn)) {
 516                                 mpath->sn = target_sn;
 517                                 mpath->flags |= MESH_PATH_SN_VALID;
 518                         } else if ((!(target_flags & MP_F_DO)) &&
 519                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 520                                 reply = true;
 521                                 metric = mpath->metric;
 522                                 target_sn = mpath->sn;
 523                                 if (target_flags & MP_F_RF)
 524                                         target_flags |= MP_F_DO;
 525                                 else
 526                                         forward = false;
 527                         }
 528                 }
 529                 rcu_read_unlock();
 530         }
 531
 532         if (reply) {
 533                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 534                 ttl = ifmsh->mshcfg.element_ttl;
 535                 if (ttl != 0) {
 536                         mhwmp_dbg("replying to the PREQ\n");
 537                         mesh_path_sel_frame_tx(MPATH_PREP, 0, target_addr,
 538                                 cpu_to_le32(target_sn), 0, orig_addr,
 539                                 cpu_to_le32(orig_sn), mgmt->sa, 0, ttl,
 540                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 541                                 0, sdata);
 542                 } else
 543                         ifmsh->mshstats.dropped_frames_ttl++;
 544         }
 545
 546         if (forward) {
 547                 u32 preq_id;
 548                 u8 hopcount, flags;
 549
 550                 ttl = PREQ_IE_TTL(preq_elem);
 551                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 552                 if (ttl <= 1) {
 553                         ifmsh->mshstats.dropped_frames_ttl++;
 554                         return;
 555                 }
 556                 mhwmp_dbg("forwarding the PREQ from %pM\n", orig_addr);
 557                 --ttl;
 558                 flags = PREQ_IE_FLAGS(preq_elem);
 559                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 560                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 561                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 562                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 563                                 cpu_to_le32(target_sn), broadcast_addr,
 564                                 hopcount, ttl, cpu_to_le32(lifetime),
 565                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 566                                 sdata);
 567                 ifmsh->mshstats.fwded_mcast++;
 568                 ifmsh->mshstats.fwded_frames++;
 569         }
 570 }
 571
 572
 573 static inline struct sta_info *
 574 next_hop_deref_protected(struct mesh_path *mpath)
 575 {
 576         return rcu_dereference_protected(mpath->next_hop,
 577                                          lockdep_is_held(&mpath->state_lock));
 578 }
 579
 580
 581 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 582                                     struct ieee80211_mgmt *mgmt,
 583                                     u8 *prep_elem, u32 metric)
 584 {
 585         struct mesh_path *mpath;
 586         u8 *target_addr, *orig_addr;
 587         u8 ttl, hopcount, flags;
 588         u8 next_hop[ETH_ALEN];
 589         u32 target_sn, orig_sn, lifetime;
 590
 591         mhwmp_dbg("received PREP from %pM\n", PREP_IE_ORIG_ADDR(prep_elem));
 592
 593         /* Note that we divert from the draft nomenclature and denominate
 594          * destination to what the draft refers to as origininator. So in this
 595          * function destnation refers to the final destination of the PREP,
 596          * which corresponds with the originator of the PREQ which this PREP
 597          * replies
 598          */
 599         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 600         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0)
 601                 /* destination, no forwarding required */
 602                 return;
 603
 604         ttl = PREP_IE_TTL(prep_elem);
 605         if (ttl <= 1) {
 606                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 607                 return;
 608         }
 609
 610         rcu_read_lock();
 611         mpath = mesh_path_lookup(target_addr, sdata);
 612         if (mpath)
 613                 spin_lock_bh(&mpath->state_lock);
 614         else
 615                 goto fail;
 616         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 617                 spin_unlock_bh(&mpath->state_lock);
 618                 goto fail;
 619         }
 620         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 621         spin_unlock_bh(&mpath->state_lock);
 622         --ttl;
 623         flags = PREP_IE_FLAGS(prep_elem);
 624         lifetime = PREP_IE_LIFETIME(prep_elem);
 625         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 626         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 627         target_sn = PREP_IE_TARGET_SN(prep_elem);
 628         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 629
 630         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 631                 cpu_to_le32(orig_sn), 0, target_addr,
 632                 cpu_to_le32(target_sn), next_hop, hopcount,
 633                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 634                 0, sdata);
 635         rcu_read_unlock();
 636
 637         sdata->u.mesh.mshstats.fwded_unicast++;
 638         sdata->u.mesh.mshstats.fwded_frames++;
 639         return;
 640
 641 fail:
 642         rcu_read_unlock();
 643         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 644 }
 645
 646 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 647                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 648 {
 649         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 650         struct mesh_path *mpath;
 651         u8 ttl;
 652         u8 *ta, *target_addr;
 653         u32 target_sn;
 654         u16 target_rcode;
 655
 656         ta = mgmt->sa;
 657         ttl = PERR_IE_TTL(perr_elem);
 658         if (ttl <= 1) {
 659                 ifmsh->mshstats.dropped_frames_ttl++;
 660                 return;
 661         }
 662         ttl--;
 663         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 664         target_sn = PERR_IE_TARGET_SN(perr_elem);
 665         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 666
 667         rcu_read_lock();
 668         mpath = mesh_path_lookup(target_addr, sdata);
 669         if (mpath) {
 670                 spin_lock_bh(&mpath->state_lock);
 671                 if (mpath->flags & MESH_PATH_ACTIVE &&
 672                     memcmp(ta, next_hop_deref_protected(mpath)->sta.addr,
 673                                                         ETH_ALEN) == 0 &&
 674                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 675                     SN_GT(target_sn, mpath->sn))) {
 676                         mpath->flags &= ~MESH_PATH_ACTIVE;
 677                         mpath->sn = target_sn;
 678                         spin_unlock_bh(&mpath->state_lock);
 679                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 680                                            cpu_to_le16(target_rcode),
 681                                            broadcast_addr, sdata);
 682                 } else
 683                         spin_unlock_bh(&mpath->state_lock);
 684         }
 685         rcu_read_unlock();
 686 }
 687
 688 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 689                                 struct ieee80211_mgmt *mgmt,
 690                                 struct ieee80211_rann_ie *rann)
 691 {
 692         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 693         struct mesh_path *mpath;
 694         u8 ttl, flags, hopcount;
 695         u8 *orig_addr;
 696         u32 orig_sn, metric;
 697         u32 interval = cpu_to_le32(IEEE80211_MESH_RANN_INTERVAL);
 698
 699         ttl = rann->rann_ttl;
 700         if (ttl <= 1) {
 701                 ifmsh->mshstats.dropped_frames_ttl++;
 702                 return;
 703         }
 704         ttl--;
 705         flags = rann->rann_flags;
 706         orig_addr = rann->rann_addr;
 707         orig_sn = rann->rann_seq;
 708         hopcount = rann->rann_hopcount;
 709         hopcount++;
 710         metric = rann->rann_metric;
 711         mhwmp_dbg("received RANN from %pM\n", orig_addr);
 712
 713         rcu_read_lock();
 714         mpath = mesh_path_lookup(orig_addr, sdata);
 715         if (!mpath) {
 716                 mesh_path_add(orig_addr, sdata);
 717                 mpath = mesh_path_lookup(orig_addr, sdata);
 718                 if (!mpath) {
 719                         rcu_read_unlock();
 720                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 721                         return;
 722                 }
 723                 mesh_queue_preq(mpath,
 724                                 PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 725         }
 726         if (mpath->sn < orig_sn) {
 727                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 728                                        cpu_to_le32(orig_sn),
 729                                        0, NULL, 0, broadcast_addr,
 730                                        hopcount, ttl, interval,
 731                                        cpu_to_le32(metric + mpath->metric),
 732                                        0, sdata);
 733                 mpath->sn = orig_sn;
 734         }
 735         rcu_read_unlock();
 736 }
 737
 738
 739 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 740                             struct ieee80211_mgmt *mgmt,
 741                             size_t len)
 742 {
 743         struct ieee802_11_elems elems;
 744         size_t baselen;
 745         u32 last_hop_metric;
 746
 747         /* need action_code */
 748         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 749                 return;
 750
 751         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 752         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 753                         len - baselen, &elems);
 754
 755         if (elems.preq) {
 756                 if (elems.preq_len != 37)
 757                         /* Right now we support just 1 destination and no AE */
 758                         return;
 759                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 760                                                       MPATH_PREQ);
 761                 if (last_hop_metric)
 762                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 763                                                 last_hop_metric);
 764         }
 765         if (elems.prep) {
 766                 if (elems.prep_len != 31)
 767                         /* Right now we support no AE */
 768                         return;
 769                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 770                                                       MPATH_PREP);
 771                 if (last_hop_metric)
 772                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 773                                                 last_hop_metric);
 774         }
 775         if (elems.perr) {
 776                 if (elems.perr_len != 15)
 777                         /* Right now we support only one destination per PERR */
 778                         return;
 779                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 780         }
 781         if (elems.rann)
 782                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 783 }
 784
 785 /**
 786  * mesh_queue_preq - queue a PREQ to a given destination
 787  *
 788  * @mpath: mesh path to discover
 789  * @flags: special attributes of the PREQ to be sent
 790  *
 791  * Locking: the function must be called from within a rcu read lock block.
 792  *
 793  */
 794 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 795 {
 796         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 797         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 798         struct mesh_preq_queue *preq_node;
 799
 800         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 801         if (!preq_node) {
 802                 mhwmp_dbg("could not allocate PREQ node\n");
 803                 return;
 804         }
 805
 806         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 807         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 808                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 809                 kfree(preq_node);
 810                 if (printk_ratelimit())
 811                         mhwmp_dbg("PREQ node queue full\n");
 812                 return;
 813         }
 814
 815         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 816         preq_node->flags = flags;
 817
 818         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 819         ++ifmsh->preq_queue_len;
 820         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 821
 822         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 823                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 824
 825         else if (time_before(jiffies, ifmsh->last_preq)) {
 826                 /* avoid long wait if did not send preqs for a long time
 827                  * and jiffies wrapped around
 828                  */
 829                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 830                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 831         } else
 832                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 833                                                 min_preq_int_jiff(sdata));
 834 }
 835
 836 /**
 837  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 838  *
 839  * @sdata: local mesh subif
 840  */
 841 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 842 {
 843         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 844         struct mesh_preq_queue *preq_node;
 845         struct mesh_path *mpath;
 846         u8 ttl, target_flags;
 847         u32 lifetime;
 848
 849         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 850         if (!ifmsh->preq_queue_len ||
 851                 time_before(jiffies, ifmsh->last_preq +
 852                                 min_preq_int_jiff(sdata))) {
 853                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 854                 return;
 855         }
 856
 857         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 858                         struct mesh_preq_queue, list);
 859         list_del(&preq_node->list);
 860         --ifmsh->preq_queue_len;
 861         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 862
 863         rcu_read_lock();
 864         mpath = mesh_path_lookup(preq_node->dst, sdata);
 865         if (!mpath)
 866                 goto enddiscovery;
 867
 868         spin_lock_bh(&mpath->state_lock);
 869         if (preq_node->flags & PREQ_Q_F_START) {
 870                 if (mpath->flags & MESH_PATH_RESOLVING) {
 871                         spin_unlock_bh(&mpath->state_lock);
 872                         goto enddiscovery;
 873                 } else {
 874                         mpath->flags &= ~MESH_PATH_RESOLVED;
 875                         mpath->flags |= MESH_PATH_RESOLVING;
 876                         mpath->discovery_retries = 0;
 877                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 878                 }
 879         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 880                         mpath->flags & MESH_PATH_RESOLVED) {
 881                 mpath->flags &= ~MESH_PATH_RESOLVING;
 882                 spin_unlock_bh(&mpath->state_lock);
 883                 goto enddiscovery;
 884         }
 885
 886         ifmsh->last_preq = jiffies;
 887
 888         if (time_after(jiffies, ifmsh->last_sn_update +
 889                                 net_traversal_jiffies(sdata)) ||
 890             time_before(jiffies, ifmsh->last_sn_update)) {
 891                 ++ifmsh->sn;
 892                 sdata->u.mesh.last_sn_update = jiffies;
 893         }
 894         lifetime = default_lifetime(sdata);
 895         ttl = sdata->u.mesh.mshcfg.element_ttl;
 896         if (ttl == 0) {
 897                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 898                 spin_unlock_bh(&mpath->state_lock);
 899                 goto enddiscovery;
 900         }
 901
 902         if (preq_node->flags & PREQ_Q_F_REFRESH)
 903                 target_flags = MP_F_DO;
 904         else
 905                 target_flags = MP_F_RF;
 906
 907         spin_unlock_bh(&mpath->state_lock);
 908         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
 909                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
 910                         cpu_to_le32(mpath->sn), broadcast_addr, 0,
 911                         ttl, cpu_to_le32(lifetime), 0,
 912                         cpu_to_le32(ifmsh->preq_id++), sdata);
 913         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 914
 915 enddiscovery:
 916         rcu_read_unlock();
 917         kfree(preq_node);
 918 }
 919
 920 /**
 921  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
 922  *
 923  * @skb: 802.11 frame to be sent
 924  * @sdata: network subif the frame will be sent through
 925  *
 926  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 927  * found, the function will start a path discovery and queue the frame so it is
 928  * sent when the path is resolved. This means the caller must not free the skb
 929  * in this case.
 930  */
 931 int mesh_nexthop_lookup(struct sk_buff *skb,
 932                         struct ieee80211_sub_if_data *sdata)
 933 {
 934         struct sk_buff *skb_to_free = NULL;
 935         struct mesh_path *mpath;
 936         struct sta_info *next_hop;
 937         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 938         u8 *target_addr = hdr->addr3;
 939         int err = 0;
 940
 941         rcu_read_lock();
 942         mpath = mesh_path_lookup(target_addr, sdata);
 943
 944         if (!mpath) {
 945                 mesh_path_add(target_addr, sdata);
 946                 mpath = mesh_path_lookup(target_addr, sdata);
 947                 if (!mpath) {
 948                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 949                         err = -ENOSPC;
 950                         goto endlookup;
 951                 }
 952         }
 953
 954         if (mpath->flags & MESH_PATH_ACTIVE) {
 955                 if (time_after(jiffies,
 956                                mpath->exp_time -
 957                                msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
 958                     !memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
 959                     !(mpath->flags & MESH_PATH_RESOLVING) &&
 960                     !(mpath->flags & MESH_PATH_FIXED)) {
 961                         mesh_queue_preq(mpath,
 962                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 963                 }
 964                 next_hop = rcu_dereference(mpath->next_hop);
 965                 if (next_hop)
 966                         memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
 967                 else
 968                         err = -ENOENT;
 969         } else {
 970                 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 971                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
 972                         /* Start discovery only if it is not running yet */
 973                         mesh_queue_preq(mpath, PREQ_Q_F_START);
 974                 }
 975
 976                 if (skb_queue_len(&mpath->frame_queue) >=
 977                                 MESH_FRAME_QUEUE_LEN)
 978                         skb_to_free = skb_dequeue(&mpath->frame_queue);
 979
 980                 info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 981                 skb_queue_tail(&mpath->frame_queue, skb);
 982                 if (skb_to_free)
 983                         mesh_path_discard_frame(skb_to_free, sdata);
 984                 err = -ENOENT;
 985         }
 986
 987 endlookup:
 988         rcu_read_unlock();
 989         return err;
 990 }
 991
 992 void mesh_path_timer(unsigned long data)
 993 {
 994         struct mesh_path *mpath = (void *) data;
 995         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 996
 997         if (sdata->local->quiescing)
 998                 return;
 999
1000         spin_lock_bh(&mpath->state_lock);
1001         if (mpath->flags & MESH_PATH_RESOLVED ||
1002                         (!(mpath->flags & MESH_PATH_RESOLVING)))
1003                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1004         else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1005                 ++mpath->discovery_retries;
1006                 mpath->discovery_timeout *= 2;
1007                 mesh_queue_preq(mpath, 0);
1008         } else {
1009                 mpath->flags = 0;
1010                 mpath->exp_time = jiffies;
1011                 mesh_path_flush_pending(mpath);
1012         }
1013
1014         spin_unlock_bh(&mpath->state_lock);
1015 }
1016
1017 void
1018 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1019 {
1020         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1021         u32 interval = cpu_to_le32(IEEE80211_MESH_RANN_INTERVAL);
1022
1023         mesh_path_sel_frame_tx(MPATH_RANN, 0, sdata->vif.addr,
1024                                cpu_to_le32(++ifmsh->sn),
1025                                0, NULL, 0, broadcast_addr,
1026                                0, sdata->u.mesh.mshcfg.element_ttl,
1027                                interval, 0, 0, sdata);
1028 }