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                                      action == MPATH_PREQ &&
 395                                      new_metric >= mpath->metric)) {
 396                                         process = false;
 397                                         fresh_info = false;
 398                                 }
 399                         }
 400                 } else {
 401                         mesh_path_add(orig_addr, sdata);
 402                         mpath = mesh_path_lookup(orig_addr, sdata);
 403                         if (!mpath) {
 404                                 rcu_read_unlock();
 405                                 return 0;
 406                         }
 407                         spin_lock_bh(&mpath->state_lock);
 408                 }
 409
 410                 if (fresh_info) {
 411                         mesh_path_assign_nexthop(mpath, sta);
 412                         mpath->flags |= MESH_PATH_SN_VALID;
 413                         mpath->metric = new_metric;
 414                         mpath->sn = orig_sn;
 415                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 416                                           ?  mpath->exp_time : exp_time;
 417                         mesh_path_activate(mpath);
 418                         spin_unlock_bh(&mpath->state_lock);
 419                         mesh_path_tx_pending(mpath);
 420                         /* draft says preq_id should be saved to, but there does
 421                          * not seem to be any use for it, skipping by now
 422                          */
 423                 } else
 424                         spin_unlock_bh(&mpath->state_lock);
 425         }
 426
 427         /* Update and check transmitter routing info */
 428         ta = mgmt->sa;
 429         if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
 430                 fresh_info = false;
 431         else {
 432                 fresh_info = true;
 433
 434                 mpath = mesh_path_lookup(ta, sdata);
 435                 if (mpath) {
 436                         spin_lock_bh(&mpath->state_lock);
 437                         if ((mpath->flags & MESH_PATH_FIXED) ||
 438                                 ((mpath->flags & MESH_PATH_ACTIVE) &&
 439                                         (last_hop_metric > mpath->metric)))
 440                                 fresh_info = false;
 441                 } else {
 442                         mesh_path_add(ta, sdata);
 443                         mpath = mesh_path_lookup(ta, sdata);
 444                         if (!mpath) {
 445                                 rcu_read_unlock();
 446                                 return 0;
 447                         }
 448                         spin_lock_bh(&mpath->state_lock);
 449                 }
 450
 451                 if (fresh_info) {
 452                         mesh_path_assign_nexthop(mpath, sta);
 453                         mpath->flags &= ~MESH_PATH_SN_VALID;
 454                         mpath->metric = last_hop_metric;
 455                         mpath->exp_time = time_after(mpath->exp_time, exp_time)
 456                                           ?  mpath->exp_time : exp_time;
 457                         mesh_path_activate(mpath);
 458                         spin_unlock_bh(&mpath->state_lock);
 459                         mesh_path_tx_pending(mpath);
 460                 } else
 461                         spin_unlock_bh(&mpath->state_lock);
 462         }
 463
 464         rcu_read_unlock();
 465
 466         return process ? new_metric : 0;
 467 }
 468
 469 static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 470                                     struct ieee80211_mgmt *mgmt,
 471                                     u8 *preq_elem, u32 metric)
 472 {
 473         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 474         struct mesh_path *mpath;
 475         u8 *target_addr, *orig_addr;
 476         u8 target_flags, ttl;
 477         u32 orig_sn, target_sn, lifetime;
 478         bool reply = false;
 479         bool forward = true;
 480
 481         /* Update target SN, if present */
 482         target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 483         orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 484         target_sn = PREQ_IE_TARGET_SN(preq_elem);
 485         orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 486         target_flags = PREQ_IE_TARGET_F(preq_elem);
 487
 488         mhwmp_dbg("received PREQ from %pM\n", orig_addr);
 489
 490         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0) {
 491                 mhwmp_dbg("PREQ is for us\n");
 492                 forward = false;
 493                 reply = true;
 494                 metric = 0;
 495                 if (time_after(jiffies, ifmsh->last_sn_update +
 496                                         net_traversal_jiffies(sdata)) ||
 497                     time_before(jiffies, ifmsh->last_sn_update)) {
 498                         target_sn = ++ifmsh->sn;
 499                         ifmsh->last_sn_update = jiffies;
 500                 }
 501         } else {
 502                 rcu_read_lock();
 503                 mpath = mesh_path_lookup(target_addr, sdata);
 504                 if (mpath) {
 505                         if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 506                                         SN_LT(mpath->sn, target_sn)) {
 507                                 mpath->sn = target_sn;
 508                                 mpath->flags |= MESH_PATH_SN_VALID;
 509                         } else if ((!(target_flags & MP_F_DO)) &&
 510                                         (mpath->flags & MESH_PATH_ACTIVE)) {
 511                                 reply = true;
 512                                 metric = mpath->metric;
 513                                 target_sn = mpath->sn;
 514                                 if (target_flags & MP_F_RF)
 515                                         target_flags |= MP_F_DO;
 516                                 else
 517                                         forward = false;
 518                         }
 519                 }
 520                 rcu_read_unlock();
 521         }
 522
 523         if (reply) {
 524                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 525                 ttl = ifmsh->mshcfg.element_ttl;
 526                 if (ttl != 0) {
 527                         mhwmp_dbg("replying to the PREQ\n");
 528                         mesh_path_sel_frame_tx(MPATH_PREP, 0, target_addr,
 529                                 cpu_to_le32(target_sn), 0, orig_addr,
 530                                 cpu_to_le32(orig_sn), mgmt->sa, 0, ttl,
 531                                 cpu_to_le32(lifetime), cpu_to_le32(metric),
 532                                 0, sdata);
 533                 } else
 534                         ifmsh->mshstats.dropped_frames_ttl++;
 535         }
 536
 537         if (forward) {
 538                 u32 preq_id;
 539                 u8 hopcount, flags;
 540
 541                 ttl = PREQ_IE_TTL(preq_elem);
 542                 lifetime = PREQ_IE_LIFETIME(preq_elem);
 543                 if (ttl <= 1) {
 544                         ifmsh->mshstats.dropped_frames_ttl++;
 545                         return;
 546                 }
 547                 mhwmp_dbg("forwarding the PREQ from %pM\n", orig_addr);
 548                 --ttl;
 549                 flags = PREQ_IE_FLAGS(preq_elem);
 550                 preq_id = PREQ_IE_PREQ_ID(preq_elem);
 551                 hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 552                 mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 553                                 cpu_to_le32(orig_sn), target_flags, target_addr,
 554                                 cpu_to_le32(target_sn), broadcast_addr,
 555                                 hopcount, ttl, cpu_to_le32(lifetime),
 556                                 cpu_to_le32(metric), cpu_to_le32(preq_id),
 557                                 sdata);
 558                 ifmsh->mshstats.fwded_mcast++;
 559                 ifmsh->mshstats.fwded_frames++;
 560         }
 561 }
 562
 563
 564 static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 565                                     struct ieee80211_mgmt *mgmt,
 566                                     u8 *prep_elem, u32 metric)
 567 {
 568         struct mesh_path *mpath;
 569         u8 *target_addr, *orig_addr;
 570         u8 ttl, hopcount, flags;
 571         u8 next_hop[ETH_ALEN];
 572         u32 target_sn, orig_sn, lifetime;
 573
 574         mhwmp_dbg("received PREP from %pM\n", PREP_IE_ORIG_ADDR(prep_elem));
 575
 576         /* Note that we divert from the draft nomenclature and denominate
 577          * destination to what the draft refers to as origininator. So in this
 578          * function destnation refers to the final destination of the PREP,
 579          * which corresponds with the originator of the PREQ which this PREP
 580          * replies
 581          */
 582         target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 583         if (memcmp(target_addr, sdata->vif.addr, ETH_ALEN) == 0)
 584                 /* destination, no forwarding required */
 585                 return;
 586
 587         ttl = PREP_IE_TTL(prep_elem);
 588         if (ttl <= 1) {
 589                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 590                 return;
 591         }
 592
 593         rcu_read_lock();
 594         mpath = mesh_path_lookup(target_addr, sdata);
 595         if (mpath)
 596                 spin_lock_bh(&mpath->state_lock);
 597         else
 598                 goto fail;
 599         if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 600                 spin_unlock_bh(&mpath->state_lock);
 601                 goto fail;
 602         }
 603         memcpy(next_hop, mpath->next_hop->sta.addr, ETH_ALEN);
 604         spin_unlock_bh(&mpath->state_lock);
 605         --ttl;
 606         flags = PREP_IE_FLAGS(prep_elem);
 607         lifetime = PREP_IE_LIFETIME(prep_elem);
 608         hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 609         orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 610         target_sn = PREP_IE_TARGET_SN(prep_elem);
 611         orig_sn = PREP_IE_ORIG_SN(prep_elem);
 612
 613         mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 614                 cpu_to_le32(orig_sn), 0, target_addr,
 615                 cpu_to_le32(target_sn), next_hop, hopcount,
 616                 ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 617                 0, sdata);
 618         rcu_read_unlock();
 619
 620         sdata->u.mesh.mshstats.fwded_unicast++;
 621         sdata->u.mesh.mshstats.fwded_frames++;
 622         return;
 623
 624 fail:
 625         rcu_read_unlock();
 626         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 627 }
 628
 629 static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 630                              struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 631 {
 632         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 633         struct mesh_path *mpath;
 634         u8 ttl;
 635         u8 *ta, *target_addr;
 636         u32 target_sn;
 637         u16 target_rcode;
 638
 639         ta = mgmt->sa;
 640         ttl = PERR_IE_TTL(perr_elem);
 641         if (ttl <= 1) {
 642                 ifmsh->mshstats.dropped_frames_ttl++;
 643                 return;
 644         }
 645         ttl--;
 646         target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 647         target_sn = PERR_IE_TARGET_SN(perr_elem);
 648         target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 649
 650         rcu_read_lock();
 651         mpath = mesh_path_lookup(target_addr, sdata);
 652         if (mpath) {
 653                 spin_lock_bh(&mpath->state_lock);
 654                 if (mpath->flags & MESH_PATH_ACTIVE &&
 655                     memcmp(ta, mpath->next_hop->sta.addr, ETH_ALEN) == 0 &&
 656                     (!(mpath->flags & MESH_PATH_SN_VALID) ||
 657                     SN_GT(target_sn, mpath->sn))) {
 658                         mpath->flags &= ~MESH_PATH_ACTIVE;
 659                         mpath->sn = target_sn;
 660                         spin_unlock_bh(&mpath->state_lock);
 661                         mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 662                                            cpu_to_le16(target_rcode),
 663                                            broadcast_addr, sdata);
 664                 } else
 665                         spin_unlock_bh(&mpath->state_lock);
 666         }
 667         rcu_read_unlock();
 668 }
 669
 670 static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 671                                 struct ieee80211_mgmt *mgmt,
 672                                 struct ieee80211_rann_ie *rann)
 673 {
 674         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 675         struct mesh_path *mpath;
 676         u8 ttl, flags, hopcount;
 677         u8 *orig_addr;
 678         u32 orig_sn, metric;
 679
 680         ttl = rann->rann_ttl;
 681         if (ttl <= 1) {
 682                 ifmsh->mshstats.dropped_frames_ttl++;
 683                 return;
 684         }
 685         ttl--;
 686         flags = rann->rann_flags;
 687         orig_addr = rann->rann_addr;
 688         orig_sn = rann->rann_seq;
 689         hopcount = rann->rann_hopcount;
 690         hopcount++;
 691         metric = rann->rann_metric;
 692         mhwmp_dbg("received RANN from %pM\n", orig_addr);
 693
 694         rcu_read_lock();
 695         mpath = mesh_path_lookup(orig_addr, sdata);
 696         if (!mpath) {
 697                 mesh_path_add(orig_addr, sdata);
 698                 mpath = mesh_path_lookup(orig_addr, sdata);
 699                 if (!mpath) {
 700                         rcu_read_unlock();
 701                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 702                         return;
 703                 }
 704                 mesh_queue_preq(mpath,
 705                                 PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 706         }
 707         if (mpath->sn < orig_sn) {
 708                 mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 709                                        cpu_to_le32(orig_sn),
 710                                        0, NULL, 0, broadcast_addr,
 711                                        hopcount, ttl, 0,
 712                                        cpu_to_le32(metric + mpath->metric),
 713                                        0, sdata);
 714                 mpath->sn = orig_sn;
 715         }
 716         rcu_read_unlock();
 717 }
 718
 719
 720 void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 721                             struct ieee80211_mgmt *mgmt,
 722                             size_t len)
 723 {
 724         struct ieee802_11_elems elems;
 725         size_t baselen;
 726         u32 last_hop_metric;
 727
 728         /* need action_code */
 729         if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 730                 return;
 731
 732         baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 733         ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 734                         len - baselen, &elems);
 735
 736         if (elems.preq) {
 737                 if (elems.preq_len != 37)
 738                         /* Right now we support just 1 destination and no AE */
 739                         return;
 740                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 741                                                       MPATH_PREQ);
 742                 if (last_hop_metric)
 743                         hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 744                                                 last_hop_metric);
 745         }
 746         if (elems.prep) {
 747                 if (elems.prep_len != 31)
 748                         /* Right now we support no AE */
 749                         return;
 750                 last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 751                                                       MPATH_PREP);
 752                 if (last_hop_metric)
 753                         hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 754                                                 last_hop_metric);
 755         }
 756         if (elems.perr) {
 757                 if (elems.perr_len != 15)
 758                         /* Right now we support only one destination per PERR */
 759                         return;
 760                 hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 761         }
 762         if (elems.rann)
 763                 hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 764 }
 765
 766 /**
 767  * mesh_queue_preq - queue a PREQ to a given destination
 768  *
 769  * @mpath: mesh path to discover
 770  * @flags: special attributes of the PREQ to be sent
 771  *
 772  * Locking: the function must be called from within a rcu read lock block.
 773  *
 774  */
 775 static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 776 {
 777         struct ieee80211_sub_if_data *sdata = mpath->sdata;
 778         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 779         struct mesh_preq_queue *preq_node;
 780
 781         preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 782         if (!preq_node) {
 783                 mhwmp_dbg("could not allocate PREQ node\n");
 784                 return;
 785         }
 786
 787         spin_lock(&ifmsh->mesh_preq_queue_lock);
 788         if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 789                 spin_unlock(&ifmsh->mesh_preq_queue_lock);
 790                 kfree(preq_node);
 791                 if (printk_ratelimit())
 792                         mhwmp_dbg("PREQ node queue full\n");
 793                 return;
 794         }
 795
 796         memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 797         preq_node->flags = flags;
 798
 799         list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 800         ++ifmsh->preq_queue_len;
 801         spin_unlock(&ifmsh->mesh_preq_queue_lock);
 802
 803         if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 804                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 805
 806         else if (time_before(jiffies, ifmsh->last_preq)) {
 807                 /* avoid long wait if did not send preqs for a long time
 808                  * and jiffies wrapped around
 809                  */
 810                 ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 811                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 812         } else
 813                 mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 814                                                 min_preq_int_jiff(sdata));
 815 }
 816
 817 /**
 818  * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 819  *
 820  * @sdata: local mesh subif
 821  */
 822 void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 823 {
 824         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 825         struct mesh_preq_queue *preq_node;
 826         struct mesh_path *mpath;
 827         u8 ttl, target_flags;
 828         u32 lifetime;
 829
 830         spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 831         if (!ifmsh->preq_queue_len ||
 832                 time_before(jiffies, ifmsh->last_preq +
 833                                 min_preq_int_jiff(sdata))) {
 834                 spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 835                 return;
 836         }
 837
 838         preq_node = list_first_entry(&ifmsh->preq_queue.list,
 839                         struct mesh_preq_queue, list);
 840         list_del(&preq_node->list);
 841         --ifmsh->preq_queue_len;
 842         spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 843
 844         rcu_read_lock();
 845         mpath = mesh_path_lookup(preq_node->dst, sdata);
 846         if (!mpath)
 847                 goto enddiscovery;
 848
 849         spin_lock_bh(&mpath->state_lock);
 850         if (preq_node->flags & PREQ_Q_F_START) {
 851                 if (mpath->flags & MESH_PATH_RESOLVING) {
 852                         spin_unlock_bh(&mpath->state_lock);
 853                         goto enddiscovery;
 854                 } else {
 855                         mpath->flags &= ~MESH_PATH_RESOLVED;
 856                         mpath->flags |= MESH_PATH_RESOLVING;
 857                         mpath->discovery_retries = 0;
 858                         mpath->discovery_timeout = disc_timeout_jiff(sdata);
 859                 }
 860         } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
 861                         mpath->flags & MESH_PATH_RESOLVED) {
 862                 mpath->flags &= ~MESH_PATH_RESOLVING;
 863                 spin_unlock_bh(&mpath->state_lock);
 864                 goto enddiscovery;
 865         }
 866
 867         ifmsh->last_preq = jiffies;
 868
 869         if (time_after(jiffies, ifmsh->last_sn_update +
 870                                 net_traversal_jiffies(sdata)) ||
 871             time_before(jiffies, ifmsh->last_sn_update)) {
 872                 ++ifmsh->sn;
 873                 sdata->u.mesh.last_sn_update = jiffies;
 874         }
 875         lifetime = default_lifetime(sdata);
 876         ttl = sdata->u.mesh.mshcfg.element_ttl;
 877         if (ttl == 0) {
 878                 sdata->u.mesh.mshstats.dropped_frames_ttl++;
 879                 spin_unlock_bh(&mpath->state_lock);
 880                 goto enddiscovery;
 881         }
 882
 883         if (preq_node->flags & PREQ_Q_F_REFRESH)
 884                 target_flags = MP_F_DO;
 885         else
 886                 target_flags = MP_F_RF;
 887
 888         spin_unlock_bh(&mpath->state_lock);
 889         mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
 890                         cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
 891                         cpu_to_le32(mpath->sn), broadcast_addr, 0,
 892                         ttl, cpu_to_le32(lifetime), 0,
 893                         cpu_to_le32(ifmsh->preq_id++), sdata);
 894         mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
 895
 896 enddiscovery:
 897         rcu_read_unlock();
 898         kfree(preq_node);
 899 }
 900
 901 /**
 902  * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame
 903  *
 904  * @skb: 802.11 frame to be sent
 905  * @sdata: network subif the frame will be sent through
 906  *
 907  * Returns: 0 if the next hop was found. Nonzero otherwise. If no next hop is
 908  * found, the function will start a path discovery and queue the frame so it is
 909  * sent when the path is resolved. This means the caller must not free the skb
 910  * in this case.
 911  */
 912 int mesh_nexthop_lookup(struct sk_buff *skb,
 913                         struct ieee80211_sub_if_data *sdata)
 914 {
 915         struct sk_buff *skb_to_free = NULL;
 916         struct mesh_path *mpath;
 917         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 918         u8 *target_addr = hdr->addr3;
 919         int err = 0;
 920
 921         rcu_read_lock();
 922         mpath = mesh_path_lookup(target_addr, sdata);
 923
 924         if (!mpath) {
 925                 mesh_path_add(target_addr, sdata);
 926                 mpath = mesh_path_lookup(target_addr, sdata);
 927                 if (!mpath) {
 928                         sdata->u.mesh.mshstats.dropped_frames_no_route++;
 929                         err = -ENOSPC;
 930                         goto endlookup;
 931                 }
 932         }
 933
 934         if (mpath->flags & MESH_PATH_ACTIVE) {
 935                 if (time_after(jiffies,
 936                                mpath->exp_time -
 937                                msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
 938                     !memcmp(sdata->vif.addr, hdr->addr4, ETH_ALEN) &&
 939                     !(mpath->flags & MESH_PATH_RESOLVING) &&
 940                     !(mpath->flags & MESH_PATH_FIXED)) {
 941                         mesh_queue_preq(mpath,
 942                                         PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 943                 }
 944                 memcpy(hdr->addr1, mpath->next_hop->sta.addr, ETH_ALEN);
 945         } else {
 946                 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 947                 if (!(mpath->flags & MESH_PATH_RESOLVING)) {
 948                         /* Start discovery only if it is not running yet */
 949                         mesh_queue_preq(mpath, PREQ_Q_F_START);
 950                 }
 951
 952                 if (skb_queue_len(&mpath->frame_queue) >=
 953                                 MESH_FRAME_QUEUE_LEN)
 954                         skb_to_free = skb_dequeue(&mpath->frame_queue);
 955
 956                 info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 957                 skb_queue_tail(&mpath->frame_queue, skb);
 958                 if (skb_to_free)
 959                         mesh_path_discard_frame(skb_to_free, sdata);
 960                 err = -ENOENT;
 961         }
 962
 963 endlookup:
 964         rcu_read_unlock();
 965         return err;
 966 }
 967
 968 void mesh_path_timer(unsigned long data)
 969 {
 970         struct ieee80211_sub_if_data *sdata;
 971         struct mesh_path *mpath;
 972
 973         rcu_read_lock();
 974         mpath = (struct mesh_path *) data;
 975         mpath = rcu_dereference(mpath);
 976         if (!mpath)
 977                 goto endmpathtimer;
 978         sdata = mpath->sdata;
 979
 980         if (sdata->local->quiescing) {
 981                 rcu_read_unlock();
 982                 return;
 983         }
 984
 985         spin_lock_bh(&mpath->state_lock);
 986         if (mpath->flags & MESH_PATH_RESOLVED ||
 987                         (!(mpath->flags & MESH_PATH_RESOLVING)))
 988                 mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
 989         else if (mpath->discovery_retries < max_preq_retries(sdata)) {
 990                 ++mpath->discovery_retries;
 991                 mpath->discovery_timeout *= 2;
 992                 mesh_queue_preq(mpath, 0);
 993         } else {
 994                 mpath->flags = 0;
 995                 mpath->exp_time = jiffies;
 996                 mesh_path_flush_pending(mpath);
 997         }
 998
 999         spin_unlock_bh(&mpath->state_lock);
1000 endmpathtimer:
1001         rcu_read_unlock();
1002 }
1003
1004 void
1005 mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1006 {
1007         struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1008
1009         mesh_path_sel_frame_tx(MPATH_RANN, 0, sdata->vif.addr,
1010                                cpu_to_le32(++ifmsh->sn),
1011                                0, NULL, 0, broadcast_addr,
1012                                0, sdata->u.mesh.mshcfg.element_ttl,
1013                                0, 0, 0, sdata);
1014 }