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->metric = last_hop_metric;
 453                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 454                                           ?  mpath->exp_time : exp_time;
 455                         mesh_path_activate(mpath);
 456                         spin_unlock_bh(&mpath->state_lock);
 457                         mesh_path_tx_pending(mpath);
 458                 } else
 459                         spin_unlock_bh(&mpath->state_lock);
 460         }
 461
 462         rcu_read_unlock();
 463
 464         return process ? new_metric : 0;
 465 }
 466
 467 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 468                                     struct ieee80211_mgmt *mgmt,
 469                                     u8 *preq_elem, u32 metric)
 470 {
 471         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 472         struct mesh_path *mpath;
 473         u8 *target_addr, *orig_addr;
 474         u8 target_flags, ttl;
 475         u32 orig_sn, target_sn, lifetime;
 476         bool reply = false;
 477         bool forward = true;
 478
 479         /* Update target SN, if present */
 480         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 481         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 482         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 483         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 484         target_flags = PREQ_IE_TARGET_F(preq_elem);
 485
 486         mhwmp_dbg("received PREQ from %pM\n", orig_addr);
 487
 488         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 489                 mhwmp_dbg("PREQ is for us\n");
 490                 forward = false;
 491                 reply = true;
 492                 metric = 0;
 493                 if (time_after(jiffies, ifmsh->last_sn_update +
 494                                         net_traversal_jiffies(sdata)) ||
 495                     time_before(jiffies, ifmsh->last_sn_update)) {
 496                         target_sn = ++ifmsh->sn;
 497                         ifmsh->last_sn_update = jiffies;
 498                 }
 499         } else {
 500                 rcu_read_lock();
 501                 mpath = mesh_path_lookup(target_addr, sdata);
 502                 if (mpath) {
 503                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 504                                         SN_LT(mpath->sn, target_sn)) {
 505                                 mpath->sn = target_sn;
 506                                 mpath->flags |= MESH_PATH_SN_VALID;
 507                         } else if ((!(target_flags & MP_F_DO)) &&
 508                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 509                                 reply = true;
 510                                 metric = mpath->metric;
 511                                 target_sn = mpath->sn;
 512                                 if (target_flags & MP_F_RF)
 513                                         target_flags |= MP_F_DO;
 514                                 else
 515                                         forward = false;
 516                         }
 517                 }
 518                 rcu_read_unlock();
 519         }
 520
 521         if (reply) {
 522                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 523                 ttl = ifmsh->mshcfg.element_ttl;
 524                 if (ttl != 0) {
 525                         mhwmp_dbg("replying to the PREQ\n");
 526                         mesh_path_sel_frame_tx(MPATH_PREP, 0, target_addr,
 527                                 cpu_to_le32(target_sn), 0, orig_addr,
 528                                 cpu_to_le32(orig_sn), mgmt->sa, 0, ttl,
 529                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 530                                 0, sdata);
 531                 } else
 532                         ifmsh->mshstats.dropped_frames_ttl++;
 533         }
 534
 535         if (forward) {
 536                 u32 preq_id;
 537                 u8 hopcount, flags;
 538
 539                 ttl = PREQ_IE_TTL(preq_elem);
 540                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 541                 if (ttl <= 1) {
 542                         ifmsh->mshstats.dropped_frames_ttl++;
 543                         return;
 544                 }
 545                 mhwmp_dbg("forwarding the PREQ from %pM\n", orig_addr);
 546                 --ttl;
 547                 flags = PREQ_IE_FLAGS(preq_elem);
 548                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 549                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 550                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 551                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 552                                 cpu_to_le32(target_sn), broadcast_addr,
 553                                 hopcount, ttl, cpu_to_le32(lifetime),
 554                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 555                                 sdata);
 556                 ifmsh->mshstats.fwded_mcast++;
 557                 ifmsh->mshstats.fwded_frames++;
 558         }
 559 }
 560
 561
 562 static inline struct sta_info *
 563 next_hop_deref_protected(struct mesh_path *mpath)
 564 {
 565         return rcu_dereference_protected(mpath->next_hop,
 566                                          lockdep_is_held(&mpath->state_lock));
 567 }
 568
 569
 570 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 571                                     struct ieee80211_mgmt *mgmt,
 572                                     u8 *prep_elem, u32 metric)
 573 {
 574         struct mesh_path *mpath;
 575         u8 *target_addr, *orig_addr;
 576         u8 ttl, hopcount, flags;
 577         u8 next_hop[ETH_ALEN];
 578         u32 target_sn, orig_sn, lifetime;
 579
 580         mhwmp_dbg("received PREP from %pM\n", PREP_IE_ORIG_ADDR(prep_elem));
 581
 582         /* Note that we divert from the draft nomenclature and denominate
 583          * destination to what the draft refers to as origininator. So in this
 584          * function destnation refers to the final destination of the PREP,
 585          * which corresponds with the originator of the PREQ which this PREP
 586          * replies
 587          */
 588         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 589         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0)
 590                 /* destination, no forwarding required */
 591                 return;
 592
 593         ttl = PREP_IE_TTL(prep_elem);
 594         if (ttl <= 1) {
 595                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 596                 return;
 597         }
 598
 599         rcu_read_lock();
 600         mpath = mesh_path_lookup(target_addr, sdata);
 601         if (mpath)
 602                 spin_lock_bh(&mpath->state_lock);
 603         else
 604                 goto fail;
 605         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 606                 spin_unlock_bh(&mpath->state_lock);
 607                 goto fail;
 608         }
 609         memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 610         spin_unlock_bh(&mpath->state_lock);
 611         --ttl;
 612         flags = PREP_IE_FLAGS(prep_elem);
 613         lifetime = PREP_IE_LIFETIME(prep_elem);
 614         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 615         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 616         target_sn = PREP_IE_TARGET_SN(prep_elem);
 617         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 618
 619         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 620                 cpu_to_le32(orig_sn), 0, target_addr,
 621                 cpu_to_le32(target_sn), next_hop, hopcount,
 622                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 623                 0, sdata);
 624         rcu_read_unlock();
 625
 626         sdata->u.mesh.mshstats.fwded_unicast++;
 627         sdata->u.mesh.mshstats.fwded_frames++;
 628         return;
 629
 630 fail:
 631         rcu_read_unlock();
 632         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 633 }
 634
 635 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 636                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 637 {
 638         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 639         struct mesh_path *mpath;
 640         u8 ttl;
 641         u8 *ta, *target_addr;
 642         u32 target_sn;
 643         u16 target_rcode;
 644
 645         ta = mgmt->sa;
 646         ttl = PERR_IE_TTL(perr_elem);
 647         if (ttl <= 1) {
 648                 ifmsh->mshstats.dropped_frames_ttl++;
 649                 return;
 650         }
 651         ttl--;
 652         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 653         target_sn = PERR_IE_TARGET_SN(perr_elem);
 654         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 655
 656         rcu_read_lock();
 657         mpath = mesh_path_lookup(target_addr, sdata);
 658         if (mpath) {
 659                 spin_lock_bh(&mpath->state_lock);
 660                 if (mpath->flags & MESH_PATH_ACTIVE &&
 661                     memcmp(ta, next_hop_deref_protected(mpath)->sta.addr,
 662                                                         ETH_ALEN) == 0 &&
 663                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 664                     SN_GT(target_sn, mpath->sn))) {
 665                         mpath->flags &= ~MESH_PATH_ACTIVE;
 666                         mpath->sn = target_sn;
 667                         spin_unlock_bh(&mpath->state_lock);
 668                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 669                                            cpu_to_le16(target_rcode),
 670                                            broadcast_addr, sdata);
 671                 } else
 672                         spin_unlock_bh(&mpath->state_lock);
 673         }
 674         rcu_read_unlock();
 675 }
 676
 677 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 678                                 struct ieee80211_mgmt *mgmt,
 679                                 struct ieee80211_rann_ie *rann)
 680 {
 681         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 682         struct mesh_path *mpath;
 683         u8 ttl, flags, hopcount;
 684         u8 *orig_addr;
 685         u32 orig_sn, metric;
 686
 687         ttl = rann->rann_ttl;
 688         if (ttl <= 1) {
 689                 ifmsh->mshstats.dropped_frames_ttl++;
 690                 return;
 691         }
 692         ttl--;
 693         flags = rann->rann_flags;
 694         orig_addr = rann->rann_addr;
 695         orig_sn = rann->rann_seq;
 696         hopcount = rann->rann_hopcount;
 697         hopcount++;
 698         metric = rann->rann_metric;
 699         mhwmp_dbg("received RANN from %pM\n", orig_addr);
 700
 701         rcu_read_lock();
 702         mpath = mesh_path_lookup(orig_addr, sdata);
 703         if (!mpath) {
 704                 mesh_path_add(orig_addr, sdata);
 705                 mpath = mesh_path_lookup(orig_addr, sdata);
 706                 if (!mpath) {
 707                         rcu_read_unlock();
 708                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 709                         return;
 710                 }
 711                 mesh_queue_preq(mpath,
 712                                 PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 713         }
 714         if (mpath->sn < orig_sn) {
 715                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 716                                        cpu_to_le32(orig_sn),
 717                                        0, NULL, 0, broadcast_addr,
 718                                        hopcount, ttl, 0,
 719                                        cpu_to_le32(metric + mpath->metric),
 720                                        0, sdata);
 721                 mpath->sn = orig_sn;
 722         }
 723         rcu_read_unlock();
 724 }
 725
 726
 727 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 728                             struct ieee80211_mgmt *mgmt,
 729                             size_t len)
 730 {
 731         struct ieee802_11_elems elems;
 732         size_t baselen;
 733         u32 last_hop_metric;
 734
 735         /* need action_code */
 736         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 737                 return;
 738
 739         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 740         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 741                         len - baselen, &elems);
 742
 743         if (elems.preq) {
 744                 if (elems.preq_len != 37)
 745                         /* Right now we support just 1 destination and no AE */
 746                         return;
 747                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 748                                                       MPATH_PREQ);
 749                 if (last_hop_metric)
 750                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 751                                                 last_hop_metric);
 752         }
 753         if (elems.prep) {
 754                 if (elems.prep_len != 31)
 755                         /* Right now we support no AE */
 756                         return;
 757                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 758                                                       MPATH_PREP);
 759                 if (last_hop_metric)
 760                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 761                                                 last_hop_metric);
 762         }
 763         if (elems.perr) {
 764                 if (elems.perr_len != 15)
 765                         /* Right now we support only one destination per PERR */
 766                         return;
 767                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 768         }
 769         if (elems.rann)
 770                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 771 }
 772
 773 /**
 774  * mesh_queue_preq - queue a PREQ to a given destination
 775  *
 776  * @mpath: mesh path to discover
 777  * @flags: special attributes of the PREQ to be sent
 778  *
 779  * Locking: the function must be called from within a rcu read lock block.
 780  *
 781  */
 782 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 783 {
 784         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 785         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 786         struct mesh_preq_queue *preq_node;
 787
 788         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 789         if (!preq_node) {
 790                 mhwmp_dbg("could not allocate PREQ node\n");
 791                 return;
 792         }
 793
 794         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 795         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 796                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 797                 kfree(preq_node);
 798                 if (printk_ratelimit())
 799                         mhwmp_dbg("PREQ node queue full\n");
 800                 return;
 801         }
 802
 803         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 804         preq_node->flags = flags;
 805
 806         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 807         ++ifmsh->preq_queue_len;
 808         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 809
 810         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 811                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 812
 813         else if (time_before(jiffies, ifmsh->last_preq)) {
 814                 /* avoid long wait if did not send preqs for a long time
 815                  * and jiffies wrapped around
 816                  */
 817                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 818                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 819         } else
 820                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 821                                                 min_preq_int_jiff(sdata));
 822 }
 823
 824 /**
 825  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 826  *
 827  * @sdata: local mesh subif
 828  */
 829 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 830 {
 831         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 832         struct mesh_preq_queue *preq_node;
 833         struct mesh_path *mpath;
 834         u8 ttl, target_flags;
 835         u32 lifetime;
 836
 837         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 838         if (!ifmsh->preq_queue_len ||
 839                 time_before(jiffies, ifmsh->last_preq +
 840                                 min_preq_int_jiff(sdata))) {
 841                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 842                 return;
 843         }
 844
 845         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 846                         struct mesh_preq_queue, list);
 847         list_del(&preq_node->list);
 848         --ifmsh->preq_queue_len;
 849         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 850
 851         rcu_read_lock();
 852         mpath = mesh_path_lookup(preq_node->dst, sdata);
 853         if (!mpath)
 854                 goto enddiscovery;
 855
 856         spin_lock_bh(&mpath->state_lock);
 857         if (preq_node->flags & PREQ_Q_F_START) {
 858                 if (mpath->flags & MESH_PATH_RESOLVING) {
 859                         spin_unlock_bh(&mpath->state_lock);
 860                         goto enddiscovery;
 861                 } else {
 862                         mpath->flags &= ~MESH_PATH_RESOLVED;
 863                         mpath->flags |= MESH_PATH_RESOLVING;
 864                         mpath->discovery_retries = 0;
 865                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 866                 }
 867         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 868                         mpath->flags & MESH_PATH_RESOLVED) {
 869                 mpath->flags &= ~MESH_PATH_RESOLVING;
 870                 spin_unlock_bh(&mpath->state_lock);
 871                 goto enddiscovery;
 872         }
 873
 874         ifmsh->last_preq = jiffies;
 875
 876         if (time_after(jiffies, ifmsh->last_sn_update +
 877                                 net_traversal_jiffies(sdata)) ||
 878             time_before(jiffies, ifmsh->last_sn_update)) {
 879                 ++ifmsh->sn;
 880                 sdata->u.mesh.last_sn_update = jiffies;
 881         }
 882         lifetime = default_lifetime(sdata);
 883         ttl = sdata->u.mesh.mshcfg.element_ttl;
 884         if (ttl == 0) {
 885                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 886                 spin_unlock_bh(&mpath->state_lock);
 887                 goto enddiscovery;
 888         }
 889
 890         if (preq_node->flags & PREQ_Q_F_REFRESH)
 891                 target_flags = MP_F_DO;
 892         else
 893                 target_flags = MP_F_RF;
 894
 895         spin_unlock_bh(&mpath->state_lock);
 896         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
 897                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
 898                         cpu_to_le32(mpath->sn), broadcast_addr, 0,
 899                         ttl, cpu_to_le32(lifetime), 0,
 900                         cpu_to_le32(ifmsh->preq_id++), sdata);
 901         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 902
 903 enddiscovery:
 904         rcu_read_unlock();
 905         kfree(preq_node);
 906 }
 907
 908 /**
 909  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
 910  *
 911  * @skb: 802.11 frame to be sent
 912  * @sdata: network subif the frame will be sent through
 913  *
 914  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 915  * found, the function will start a path discovery and queue the frame so it is
 916  * sent when the path is resolved. This means the caller must not free the skb
 917  * in this case.
 918  */
 919 int mesh_nexthop_lookup(struct sk_buff *skb,
 920                         struct ieee80211_sub_if_data *sdata)
 921 {
 922         struct sk_buff *skb_to_free = NULL;
 923         struct mesh_path *mpath;
 924         struct sta_info *next_hop;
 925         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 926         u8 *target_addr = hdr->addr3;
 927         int err = 0;
 928
 929         rcu_read_lock();
 930         mpath = mesh_path_lookup(target_addr, sdata);
 931
 932         if (!mpath) {
 933                 mesh_path_add(target_addr, sdata);
 934                 mpath = mesh_path_lookup(target_addr, sdata);
 935                 if (!mpath) {
 936                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 937                         err = -ENOSPC;
 938                         goto endlookup;
 939                 }
 940         }
 941
 942         if (mpath->flags & MESH_PATH_ACTIVE) {
 943                 if (time_after(jiffies,
 944                                mpath->exp_time -
 945                                msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
 946                     !memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
 947                     !(mpath->flags & MESH_PATH_RESOLVING) &&
 948                     !(mpath->flags & MESH_PATH_FIXED)) {
 949                         mesh_queue_preq(mpath,
 950                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 951                 }
 952                 next_hop = rcu_dereference(mpath->next_hop);
 953                 if (next_hop)
 954                         memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
 955                 else
 956                         err = -ENOENT;
 957         } else {
 958                 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 959                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
 960                         /* Start discovery only if it is not running yet */
 961                         mesh_queue_preq(mpath, PREQ_Q_F_START);
 962                 }
 963
 964                 if (skb_queue_len(&mpath->frame_queue) >=
 965                                 MESH_FRAME_QUEUE_LEN)
 966                         skb_to_free = skb_dequeue(&mpath->frame_queue);
 967
 968                 info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 969                 skb_queue_tail(&mpath->frame_queue, skb);
 970                 if (skb_to_free)
 971                         mesh_path_discard_frame(skb_to_free, sdata);
 972                 err = -ENOENT;
 973         }
 974
 975 endlookup:
 976         rcu_read_unlock();
 977         return err;
 978 }
 979
 980 void mesh_path_timer(unsigned long data)
 981 {
 982         struct mesh_path *mpath = (void *) data;
 983         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 984
 985         if (sdata->local->quiescing)
 986                 return;
 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 }
1004
1005 void
1006 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1007 {
1008         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1009
1010         mesh_path_sel_frame_tx(MPATH_RANN, 0, sdata->vif.addr,
1011                                cpu_to_le32(++ifmsh->sn),
1012                                0, NULL, 0, broadcast_addr,
1013                                0, sdata->u.mesh.mshcfg.element_ttl,
1014                                0, 0, 0, sdata);
1015 }