linux/net/mac80211/mesh_hwmp.c
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   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 <linux/etherdevice.h>
  12#include <asm/unaligned.h>
  13#include "wme.h"
  14#include "mesh.h"
  15
  16#define TEST_FRAME_LEN  8192
  17#define MAX_METRIC      0xffffffff
  18#define ARITH_SHIFT     8
  19
  20#define MAX_PREQ_QUEUE_LEN      64
  21
  22/* Destination only */
  23#define MP_F_DO 0x1
  24/* Reply and forward */
  25#define MP_F_RF 0x2
  26/* Unknown Sequence Number */
  27#define MP_F_USN    0x01
  28/* Reason code Present */
  29#define MP_F_RCODE  0x02
  30
  31static void mesh_queue_preq(struct mesh_path *, u8);
  32
  33static inline u32 u32_field_get(u8 *preq_elem, int offset, bool ae)
  34{
  35        if (ae)
  36                offset += 6;
  37        return get_unaligned_le32(preq_elem + offset);
  38}
  39
  40static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
  41{
  42        if (ae)
  43                offset += 6;
  44        return get_unaligned_le16(preq_elem + offset);
  45}
  46
  47/* HWMP IE processing macros */
  48#define AE_F                    (1<<6)
  49#define AE_F_SET(x)             (*x & AE_F)
  50#define PREQ_IE_FLAGS(x)        (*(x))
  51#define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  52#define PREQ_IE_TTL(x)          (*(x + 2))
  53#define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  54#define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  55#define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  56#define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  57#define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  58#define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  59#define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  60#define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  61
  62
  63#define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  64#define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  65#define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  66#define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  67#define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  68#define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  69#define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  70#define PREP_IE_TARGET_ADDR(x)  (x + 3)
  71#define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  72
  73#define PERR_IE_TTL(x)          (*(x))
  74#define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  75#define PERR_IE_TARGET_ADDR(x)  (x + 3)
  76#define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  77#define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  78
  79#define MSEC_TO_TU(x) (x*1000/1024)
  80#define SN_GT(x, y) ((s32)(y - x) < 0)
  81#define SN_LT(x, y) ((s32)(x - y) < 0)
  82
  83#define net_traversal_jiffies(s) \
  84        msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  85#define default_lifetime(s) \
  86        MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  87#define min_preq_int_jiff(s) \
  88        (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  89#define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  90#define disc_timeout_jiff(s) \
  91        msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  92#define root_path_confirmation_jiffies(s) \
  93        msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  94
  95enum mpath_frame_type {
  96        MPATH_PREQ = 0,
  97        MPATH_PREP,
  98        MPATH_PERR,
  99        MPATH_RANN
 100};
 101
 102static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 103
 104static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 105                u8 *orig_addr, __le32 orig_sn, u8 target_flags, u8 *target,
 106                __le32 target_sn, const u8 *da, u8 hop_count, u8 ttl,
 107                __le32 lifetime, __le32 metric, __le32 preq_id,
 108                struct ieee80211_sub_if_data *sdata)
 109{
 110        struct ieee80211_local *local = sdata->local;
 111        struct sk_buff *skb;
 112        struct ieee80211_mgmt *mgmt;
 113        u8 *pos, ie_len;
 114        int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 115                      sizeof(mgmt->u.action.u.mesh_action);
 116
 117        skb = dev_alloc_skb(local->tx_headroom +
 118                            hdr_len +
 119                            2 + 37); /* max HWMP IE */
 120        if (!skb)
 121                return -1;
 122        skb_reserve(skb, local->tx_headroom);
 123        mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 124        memset(mgmt, 0, hdr_len);
 125        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 126                                          IEEE80211_STYPE_ACTION);
 127
 128        memcpy(mgmt->da, da, ETH_ALEN);
 129        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 130        /* BSSID == SA */
 131        memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 132        mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 133        mgmt->u.action.u.mesh_action.action_code =
 134                                        WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 135
 136        switch (action) {
 137        case MPATH_PREQ:
 138                mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 139                ie_len = 37;
 140                pos = skb_put(skb, 2 + ie_len);
 141                *pos++ = WLAN_EID_PREQ;
 142                break;
 143        case MPATH_PREP:
 144                mhwmp_dbg(sdata, "sending PREP to %pM\n", target);
 145                ie_len = 31;
 146                pos = skb_put(skb, 2 + ie_len);
 147                *pos++ = WLAN_EID_PREP;
 148                break;
 149        case MPATH_RANN:
 150                mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 151                ie_len = sizeof(struct ieee80211_rann_ie);
 152                pos = skb_put(skb, 2 + ie_len);
 153                *pos++ = WLAN_EID_RANN;
 154                break;
 155        default:
 156                kfree_skb(skb);
 157                return -ENOTSUPP;
 158                break;
 159        }
 160        *pos++ = ie_len;
 161        *pos++ = flags;
 162        *pos++ = hop_count;
 163        *pos++ = ttl;
 164        if (action == MPATH_PREP) {
 165                memcpy(pos, target, ETH_ALEN);
 166                pos += ETH_ALEN;
 167                memcpy(pos, &target_sn, 4);
 168                pos += 4;
 169        } else {
 170                if (action == MPATH_PREQ) {
 171                        memcpy(pos, &preq_id, 4);
 172                        pos += 4;
 173                }
 174                memcpy(pos, orig_addr, ETH_ALEN);
 175                pos += ETH_ALEN;
 176                memcpy(pos, &orig_sn, 4);
 177                pos += 4;
 178        }
 179        memcpy(pos, &lifetime, 4);      /* interval for RANN */
 180        pos += 4;
 181        memcpy(pos, &metric, 4);
 182        pos += 4;
 183        if (action == MPATH_PREQ) {
 184                *pos++ = 1; /* destination count */
 185                *pos++ = target_flags;
 186                memcpy(pos, target, ETH_ALEN);
 187                pos += ETH_ALEN;
 188                memcpy(pos, &target_sn, 4);
 189                pos += 4;
 190        } else if (action == MPATH_PREP) {
 191                memcpy(pos, orig_addr, ETH_ALEN);
 192                pos += ETH_ALEN;
 193                memcpy(pos, &orig_sn, 4);
 194                pos += 4;
 195        }
 196
 197        ieee80211_tx_skb(sdata, skb);
 198        return 0;
 199}
 200
 201
 202/*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 203 *  headroom in case the frame is encrypted. */
 204static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 205                struct sk_buff *skb)
 206{
 207        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 208
 209        skb_set_mac_header(skb, 0);
 210        skb_set_network_header(skb, 0);
 211        skb_set_transport_header(skb, 0);
 212
 213        /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 214        skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 215        skb->priority = 7;
 216
 217        info->control.vif = &sdata->vif;
 218        ieee80211_set_qos_hdr(sdata, skb);
 219}
 220
 221/**
 222 * mesh_send_path error - Sends a PERR mesh management frame
 223 *
 224 * @target: broken destination
 225 * @target_sn: SN of the broken destination
 226 * @target_rcode: reason code for this PERR
 227 * @ra: node this frame is addressed to
 228 *
 229 * Note: This function may be called with driver locks taken that the driver
 230 * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 231 * frame directly but add it to the pending queue instead.
 232 */
 233int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 234                       __le16 target_rcode, const u8 *ra,
 235                       struct ieee80211_sub_if_data *sdata)
 236{
 237        struct ieee80211_local *local = sdata->local;
 238        struct sk_buff *skb;
 239        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 240        struct ieee80211_mgmt *mgmt;
 241        u8 *pos, ie_len;
 242        int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 243                      sizeof(mgmt->u.action.u.mesh_action);
 244
 245        if (time_before(jiffies, ifmsh->next_perr))
 246                return -EAGAIN;
 247
 248        skb = dev_alloc_skb(local->tx_headroom +
 249                            hdr_len +
 250                            2 + 15 /* PERR IE */);
 251        if (!skb)
 252                return -1;
 253        skb_reserve(skb, local->tx_headroom);
 254        mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 255        memset(mgmt, 0, hdr_len);
 256        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 257                                          IEEE80211_STYPE_ACTION);
 258
 259        memcpy(mgmt->da, ra, ETH_ALEN);
 260        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 261        /* BSSID == SA */
 262        memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 263        mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 264        mgmt->u.action.u.mesh_action.action_code =
 265                                        WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 266        ie_len = 15;
 267        pos = skb_put(skb, 2 + ie_len);
 268        *pos++ = WLAN_EID_PERR;
 269        *pos++ = ie_len;
 270        /* ttl */
 271        *pos++ = ttl;
 272        /* number of destinations */
 273        *pos++ = 1;
 274        /*
 275         * flags bit, bit 1 is unset if we know the sequence number and
 276         * bit 2 is set if we have a reason code
 277         */
 278        *pos = 0;
 279        if (!target_sn)
 280                *pos |= MP_F_USN;
 281        if (target_rcode)
 282                *pos |= MP_F_RCODE;
 283        pos++;
 284        memcpy(pos, target, ETH_ALEN);
 285        pos += ETH_ALEN;
 286        memcpy(pos, &target_sn, 4);
 287        pos += 4;
 288        memcpy(pos, &target_rcode, 2);
 289
 290        /* see note in function header */
 291        prepare_frame_for_deferred_tx(sdata, skb);
 292        ifmsh->next_perr = TU_TO_EXP_TIME(
 293                                   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 294        ieee80211_add_pending_skb(local, skb);
 295        return 0;
 296}
 297
 298void ieee80211s_update_metric(struct ieee80211_local *local,
 299                struct sta_info *sta, struct sk_buff *skb)
 300{
 301        struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 302        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 303        int failed;
 304
 305        if (!ieee80211_is_data(hdr->frame_control))
 306                return;
 307
 308        failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 309
 310        /* moving average, scaled to 100 */
 311        sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
 312        if (sta->fail_avg > 95)
 313                mesh_plink_broken(sta);
 314}
 315
 316static u32 airtime_link_metric_get(struct ieee80211_local *local,
 317                                   struct sta_info *sta)
 318{
 319        struct rate_info rinfo;
 320        /* This should be adjusted for each device */
 321        int device_constant = 1 << ARITH_SHIFT;
 322        int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 323        int s_unit = 1 << ARITH_SHIFT;
 324        int rate, err;
 325        u32 tx_time, estimated_retx;
 326        u64 result;
 327
 328        if (sta->fail_avg >= 100)
 329                return MAX_METRIC;
 330
 331        sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
 332        rate = cfg80211_calculate_bitrate(&rinfo);
 333        if (WARN_ON(!rate))
 334                return MAX_METRIC;
 335
 336        err = (sta->fail_avg << ARITH_SHIFT) / 100;
 337
 338        /* bitrate is in units of 100 Kbps, while we need rate in units of
 339         * 1Mbps. This will be corrected on tx_time computation.
 340         */
 341        tx_time = (device_constant + 10 * test_frame_len / rate);
 342        estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 343        result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 344        return (u32)result;
 345}
 346
 347/**
 348 * hwmp_route_info_get - Update routing info to originator and transmitter
 349 *
 350 * @sdata: local mesh subif
 351 * @mgmt: mesh management frame
 352 * @hwmp_ie: hwmp information element (PREP or PREQ)
 353 *
 354 * This function updates the path routing information to the originator and the
 355 * transmitter of a HWMP PREQ or PREP frame.
 356 *
 357 * Returns: metric to frame originator or 0 if the frame should not be further
 358 * processed
 359 *
 360 * Notes: this function is the only place (besides user-provided info) where
 361 * path routing information is updated.
 362 */
 363static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 364                            struct ieee80211_mgmt *mgmt,
 365                            u8 *hwmp_ie, enum mpath_frame_type action)
 366{
 367        struct ieee80211_local *local = sdata->local;
 368        struct mesh_path *mpath;
 369        struct sta_info *sta;
 370        bool fresh_info;
 371        u8 *orig_addr, *ta;
 372        u32 orig_sn, orig_metric;
 373        unsigned long orig_lifetime, exp_time;
 374        u32 last_hop_metric, new_metric;
 375        bool process = true;
 376
 377        rcu_read_lock();
 378        sta = sta_info_get(sdata, mgmt->sa);
 379        if (!sta) {
 380                rcu_read_unlock();
 381                return 0;
 382        }
 383
 384        last_hop_metric = airtime_link_metric_get(local, sta);
 385        /* Update and check originator routing info */
 386        fresh_info = true;
 387
 388        switch (action) {
 389        case MPATH_PREQ:
 390                orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 391                orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 392                orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 393                orig_metric = PREQ_IE_METRIC(hwmp_ie);
 394                break;
 395        case MPATH_PREP:
 396                /* Originator here refers to the MP that was the target in the
 397                 * Path Request. We divert from the nomenclature in the draft
 398                 * so that we can easily use a single function to gather path
 399                 * information from both PREQ and PREP frames.
 400                 */
 401                orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 402                orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 403                orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 404                orig_metric = PREP_IE_METRIC(hwmp_ie);
 405                break;
 406        default:
 407                rcu_read_unlock();
 408                return 0;
 409        }
 410        new_metric = orig_metric + last_hop_metric;
 411        if (new_metric < orig_metric)
 412                new_metric = MAX_METRIC;
 413        exp_time = TU_TO_EXP_TIME(orig_lifetime);
 414
 415        if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 416                /* This MP is the originator, we are not interested in this
 417                 * frame, except for updating transmitter's path info.
 418                 */
 419                process = false;
 420                fresh_info = false;
 421        } else {
 422                mpath = mesh_path_lookup(orig_addr, sdata);
 423                if (mpath) {
 424                        spin_lock_bh(&mpath->state_lock);
 425                        if (mpath->flags & MESH_PATH_FIXED)
 426                                fresh_info = false;
 427                        else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 428                            (mpath->flags & MESH_PATH_SN_VALID)) {
 429                                if (SN_GT(mpath->sn, orig_sn) ||
 430                                    (mpath->sn == orig_sn &&
 431                                     new_metric >= mpath->metric)) {
 432                                        process = false;
 433                                        fresh_info = false;
 434                                }
 435                        }
 436                } else {
 437                        mesh_path_add(orig_addr, sdata);
 438                        mpath = mesh_path_lookup(orig_addr, sdata);
 439                        if (!mpath) {
 440                                rcu_read_unlock();
 441                                return 0;
 442                        }
 443                        spin_lock_bh(&mpath->state_lock);
 444                }
 445
 446                if (fresh_info) {
 447                        mesh_path_assign_nexthop(mpath, sta);
 448                        mpath->flags |= MESH_PATH_SN_VALID;
 449                        mpath->metric = new_metric;
 450                        mpath->sn = orig_sn;
 451                        mpath->exp_time = time_after(mpath->exp_time, exp_time)
 452                                          ?  mpath->exp_time : exp_time;
 453                        mesh_path_activate(mpath);
 454                        spin_unlock_bh(&mpath->state_lock);
 455                        mesh_path_tx_pending(mpath);
 456                        /* draft says preq_id should be saved to, but there does
 457                         * not seem to be any use for it, skipping by now
 458                         */
 459                } else
 460                        spin_unlock_bh(&mpath->state_lock);
 461        }
 462
 463        /* Update and check transmitter routing info */
 464        ta = mgmt->sa;
 465        if (ether_addr_equal(orig_addr, ta))
 466                fresh_info = false;
 467        else {
 468                fresh_info = true;
 469
 470                mpath = mesh_path_lookup(ta, sdata);
 471                if (mpath) {
 472                        spin_lock_bh(&mpath->state_lock);
 473                        if ((mpath->flags & MESH_PATH_FIXED) ||
 474                                ((mpath->flags & MESH_PATH_ACTIVE) &&
 475                                        (last_hop_metric > mpath->metric)))
 476                                fresh_info = false;
 477                } else {
 478                        mesh_path_add(ta, sdata);
 479                        mpath = mesh_path_lookup(ta, sdata);
 480                        if (!mpath) {
 481                                rcu_read_unlock();
 482                                return 0;
 483                        }
 484                        spin_lock_bh(&mpath->state_lock);
 485                }
 486
 487                if (fresh_info) {
 488                        mesh_path_assign_nexthop(mpath, sta);
 489                        mpath->metric = last_hop_metric;
 490                        mpath->exp_time = time_after(mpath->exp_time, exp_time)
 491                                          ?  mpath->exp_time : exp_time;
 492                        mesh_path_activate(mpath);
 493                        spin_unlock_bh(&mpath->state_lock);
 494                        mesh_path_tx_pending(mpath);
 495                } else
 496                        spin_unlock_bh(&mpath->state_lock);
 497        }
 498
 499        rcu_read_unlock();
 500
 501        return process ? new_metric : 0;
 502}
 503
 504static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 505                                    struct ieee80211_mgmt *mgmt,
 506                                    u8 *preq_elem, u32 metric)
 507{
 508        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 509        struct mesh_path *mpath = NULL;
 510        u8 *target_addr, *orig_addr;
 511        const u8 *da;
 512        u8 target_flags, ttl, flags;
 513        u32 orig_sn, target_sn, lifetime, orig_metric;
 514        bool reply = false;
 515        bool forward = true;
 516        bool root_is_gate;
 517
 518        /* Update target SN, if present */
 519        target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 520        orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 521        target_sn = PREQ_IE_TARGET_SN(preq_elem);
 522        orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 523        target_flags = PREQ_IE_TARGET_F(preq_elem);
 524        orig_metric = metric;
 525        /* Proactive PREQ gate announcements */
 526        flags = PREQ_IE_FLAGS(preq_elem);
 527        root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 528
 529        mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 530
 531        if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 532                mhwmp_dbg(sdata, "PREQ is for us\n");
 533                forward = false;
 534                reply = true;
 535                metric = 0;
 536                if (time_after(jiffies, ifmsh->last_sn_update +
 537                                        net_traversal_jiffies(sdata)) ||
 538                    time_before(jiffies, ifmsh->last_sn_update)) {
 539                        target_sn = ++ifmsh->sn;
 540                        ifmsh->last_sn_update = jiffies;
 541                }
 542        } else if (is_broadcast_ether_addr(target_addr) &&
 543                   (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 544                rcu_read_lock();
 545                mpath = mesh_path_lookup(orig_addr, sdata);
 546                if (mpath) {
 547                        if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 548                                reply = true;
 549                                target_addr = sdata->vif.addr;
 550                                target_sn = ++ifmsh->sn;
 551                                metric = 0;
 552                                ifmsh->last_sn_update = jiffies;
 553                        }
 554                        if (root_is_gate)
 555                                mesh_path_add_gate(mpath);
 556                }
 557                rcu_read_unlock();
 558        } else {
 559                rcu_read_lock();
 560                mpath = mesh_path_lookup(target_addr, sdata);
 561                if (mpath) {
 562                        if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 563                                        SN_LT(mpath->sn, target_sn)) {
 564                                mpath->sn = target_sn;
 565                                mpath->flags |= MESH_PATH_SN_VALID;
 566                        } else if ((!(target_flags & MP_F_DO)) &&
 567                                        (mpath->flags & MESH_PATH_ACTIVE)) {
 568                                reply = true;
 569                                metric = mpath->metric;
 570                                target_sn = mpath->sn;
 571                                if (target_flags & MP_F_RF)
 572                                        target_flags |= MP_F_DO;
 573                                else
 574                                        forward = false;
 575                        }
 576                }
 577                rcu_read_unlock();
 578        }
 579
 580        if (reply) {
 581                lifetime = PREQ_IE_LIFETIME(preq_elem);
 582                ttl = ifmsh->mshcfg.element_ttl;
 583                if (ttl != 0) {
 584                        mhwmp_dbg(sdata, "replying to the PREQ\n");
 585                        mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 586                                cpu_to_le32(orig_sn), 0, target_addr,
 587                                cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 588                                cpu_to_le32(lifetime), cpu_to_le32(metric),
 589                                0, sdata);
 590                } else {
 591                        ifmsh->mshstats.dropped_frames_ttl++;
 592                }
 593        }
 594
 595        if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 596                u32 preq_id;
 597                u8 hopcount;
 598
 599                ttl = PREQ_IE_TTL(preq_elem);
 600                lifetime = PREQ_IE_LIFETIME(preq_elem);
 601                if (ttl <= 1) {
 602                        ifmsh->mshstats.dropped_frames_ttl++;
 603                        return;
 604                }
 605                mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 606                --ttl;
 607                preq_id = PREQ_IE_PREQ_ID(preq_elem);
 608                hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 609                da = (mpath && mpath->is_root) ?
 610                        mpath->rann_snd_addr : broadcast_addr;
 611
 612                if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 613                        target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 614                        target_sn = PREQ_IE_TARGET_SN(preq_elem);
 615                        metric = orig_metric;
 616                }
 617
 618                mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 619                                cpu_to_le32(orig_sn), target_flags, target_addr,
 620                                cpu_to_le32(target_sn), da,
 621                                hopcount, ttl, cpu_to_le32(lifetime),
 622                                cpu_to_le32(metric), cpu_to_le32(preq_id),
 623                                sdata);
 624                if (!is_multicast_ether_addr(da))
 625                        ifmsh->mshstats.fwded_unicast++;
 626                else
 627                        ifmsh->mshstats.fwded_mcast++;
 628                ifmsh->mshstats.fwded_frames++;
 629        }
 630}
 631
 632
 633static inline struct sta_info *
 634next_hop_deref_protected(struct mesh_path *mpath)
 635{
 636        return rcu_dereference_protected(mpath->next_hop,
 637                                         lockdep_is_held(&mpath->state_lock));
 638}
 639
 640
 641static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 642                                    struct ieee80211_mgmt *mgmt,
 643                                    u8 *prep_elem, u32 metric)
 644{
 645        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 646        struct mesh_path *mpath;
 647        u8 *target_addr, *orig_addr;
 648        u8 ttl, hopcount, flags;
 649        u8 next_hop[ETH_ALEN];
 650        u32 target_sn, orig_sn, lifetime;
 651
 652        mhwmp_dbg(sdata, "received PREP from %pM\n",
 653                  PREP_IE_ORIG_ADDR(prep_elem));
 654
 655        orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 656        if (ether_addr_equal(orig_addr, sdata->vif.addr))
 657                /* destination, no forwarding required */
 658                return;
 659
 660        if (!ifmsh->mshcfg.dot11MeshForwarding)
 661                return;
 662
 663        ttl = PREP_IE_TTL(prep_elem);
 664        if (ttl <= 1) {
 665                sdata->u.mesh.mshstats.dropped_frames_ttl++;
 666                return;
 667        }
 668
 669        rcu_read_lock();
 670        mpath = mesh_path_lookup(orig_addr, sdata);
 671        if (mpath)
 672                spin_lock_bh(&mpath->state_lock);
 673        else
 674                goto fail;
 675        if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 676                spin_unlock_bh(&mpath->state_lock);
 677                goto fail;
 678        }
 679        memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 680        spin_unlock_bh(&mpath->state_lock);
 681        --ttl;
 682        flags = PREP_IE_FLAGS(prep_elem);
 683        lifetime = PREP_IE_LIFETIME(prep_elem);
 684        hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 685        target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 686        target_sn = PREP_IE_TARGET_SN(prep_elem);
 687        orig_sn = PREP_IE_ORIG_SN(prep_elem);
 688
 689        mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 690                cpu_to_le32(orig_sn), 0, target_addr,
 691                cpu_to_le32(target_sn), next_hop, hopcount,
 692                ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 693                0, sdata);
 694        rcu_read_unlock();
 695
 696        sdata->u.mesh.mshstats.fwded_unicast++;
 697        sdata->u.mesh.mshstats.fwded_frames++;
 698        return;
 699
 700fail:
 701        rcu_read_unlock();
 702        sdata->u.mesh.mshstats.dropped_frames_no_route++;
 703}
 704
 705static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 706                             struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 707{
 708        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 709        struct mesh_path *mpath;
 710        u8 ttl;
 711        u8 *ta, *target_addr;
 712        u32 target_sn;
 713        u16 target_rcode;
 714
 715        ta = mgmt->sa;
 716        ttl = PERR_IE_TTL(perr_elem);
 717        if (ttl <= 1) {
 718                ifmsh->mshstats.dropped_frames_ttl++;
 719                return;
 720        }
 721        ttl--;
 722        target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 723        target_sn = PERR_IE_TARGET_SN(perr_elem);
 724        target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 725
 726        rcu_read_lock();
 727        mpath = mesh_path_lookup(target_addr, sdata);
 728        if (mpath) {
 729                struct sta_info *sta;
 730
 731                spin_lock_bh(&mpath->state_lock);
 732                sta = next_hop_deref_protected(mpath);
 733                if (mpath->flags & MESH_PATH_ACTIVE &&
 734                    ether_addr_equal(ta, sta->sta.addr) &&
 735                    (!(mpath->flags & MESH_PATH_SN_VALID) ||
 736                    SN_GT(target_sn, mpath->sn))) {
 737                        mpath->flags &= ~MESH_PATH_ACTIVE;
 738                        mpath->sn = target_sn;
 739                        spin_unlock_bh(&mpath->state_lock);
 740                        if (!ifmsh->mshcfg.dot11MeshForwarding)
 741                                goto endperr;
 742                        mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 743                                           cpu_to_le16(target_rcode),
 744                                           broadcast_addr, sdata);
 745                } else
 746                        spin_unlock_bh(&mpath->state_lock);
 747        }
 748endperr:
 749        rcu_read_unlock();
 750}
 751
 752static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 753                                struct ieee80211_mgmt *mgmt,
 754                                struct ieee80211_rann_ie *rann)
 755{
 756        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 757        struct ieee80211_local *local = sdata->local;
 758        struct sta_info *sta;
 759        struct mesh_path *mpath;
 760        u8 ttl, flags, hopcount;
 761        u8 *orig_addr;
 762        u32 orig_sn, metric, metric_txsta, interval;
 763        bool root_is_gate;
 764
 765        ttl = rann->rann_ttl;
 766        flags = rann->rann_flags;
 767        root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 768        orig_addr = rann->rann_addr;
 769        orig_sn = le32_to_cpu(rann->rann_seq);
 770        interval = le32_to_cpu(rann->rann_interval);
 771        hopcount = rann->rann_hopcount;
 772        hopcount++;
 773        metric = le32_to_cpu(rann->rann_metric);
 774
 775        /*  Ignore our own RANNs */
 776        if (ether_addr_equal(orig_addr, sdata->vif.addr))
 777                return;
 778
 779        mhwmp_dbg(sdata,
 780                  "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 781                  orig_addr, mgmt->sa, root_is_gate);
 782
 783        rcu_read_lock();
 784        sta = sta_info_get(sdata, mgmt->sa);
 785        if (!sta) {
 786                rcu_read_unlock();
 787                return;
 788        }
 789
 790        metric_txsta = airtime_link_metric_get(local, sta);
 791
 792        mpath = mesh_path_lookup(orig_addr, sdata);
 793        if (!mpath) {
 794                mesh_path_add(orig_addr, sdata);
 795                mpath = mesh_path_lookup(orig_addr, sdata);
 796                if (!mpath) {
 797                        rcu_read_unlock();
 798                        sdata->u.mesh.mshstats.dropped_frames_no_route++;
 799                        return;
 800                }
 801        }
 802
 803        if (!(SN_LT(mpath->sn, orig_sn)) &&
 804            !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 805                rcu_read_unlock();
 806                return;
 807        }
 808
 809        if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 810             (time_after(jiffies, mpath->last_preq_to_root +
 811                                  root_path_confirmation_jiffies(sdata)) ||
 812             time_before(jiffies, mpath->last_preq_to_root))) &&
 813             !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 814                mhwmp_dbg(sdata,
 815                          "time to refresh root mpath %pM\n",
 816                          orig_addr);
 817                mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 818                mpath->last_preq_to_root = jiffies;
 819        }
 820
 821        mpath->sn = orig_sn;
 822        mpath->rann_metric = metric + metric_txsta;
 823        mpath->is_root = true;
 824        /* Recording RANNs sender address to send individually
 825         * addressed PREQs destined for root mesh STA */
 826        memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 827
 828        if (root_is_gate)
 829                mesh_path_add_gate(mpath);
 830
 831        if (ttl <= 1) {
 832                ifmsh->mshstats.dropped_frames_ttl++;
 833                rcu_read_unlock();
 834                return;
 835        }
 836        ttl--;
 837
 838        if (ifmsh->mshcfg.dot11MeshForwarding) {
 839                mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 840                                       cpu_to_le32(orig_sn),
 841                                       0, NULL, 0, broadcast_addr,
 842                                       hopcount, ttl, cpu_to_le32(interval),
 843                                       cpu_to_le32(metric + metric_txsta),
 844                                       0, sdata);
 845        }
 846
 847        rcu_read_unlock();
 848}
 849
 850
 851void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 852                            struct ieee80211_mgmt *mgmt,
 853                            size_t len)
 854{
 855        struct ieee802_11_elems elems;
 856        size_t baselen;
 857        u32 last_hop_metric;
 858        struct sta_info *sta;
 859
 860        /* need action_code */
 861        if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 862                return;
 863
 864        rcu_read_lock();
 865        sta = sta_info_get(sdata, mgmt->sa);
 866        if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 867                rcu_read_unlock();
 868                return;
 869        }
 870        rcu_read_unlock();
 871
 872        baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 873        ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 874                        len - baselen, &elems);
 875
 876        if (elems.preq) {
 877                if (elems.preq_len != 37)
 878                        /* Right now we support just 1 destination and no AE */
 879                        return;
 880                last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 881                                                      MPATH_PREQ);
 882                if (last_hop_metric)
 883                        hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 884                                                last_hop_metric);
 885        }
 886        if (elems.prep) {
 887                if (elems.prep_len != 31)
 888                        /* Right now we support no AE */
 889                        return;
 890                last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 891                                                      MPATH_PREP);
 892                if (last_hop_metric)
 893                        hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 894                                                last_hop_metric);
 895        }
 896        if (elems.perr) {
 897                if (elems.perr_len != 15)
 898                        /* Right now we support only one destination per PERR */
 899                        return;
 900                hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 901        }
 902        if (elems.rann)
 903                hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 904}
 905
 906/**
 907 * mesh_queue_preq - queue a PREQ to a given destination
 908 *
 909 * @mpath: mesh path to discover
 910 * @flags: special attributes of the PREQ to be sent
 911 *
 912 * Locking: the function must be called from within a rcu read lock block.
 913 *
 914 */
 915static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 916{
 917        struct ieee80211_sub_if_data *sdata = mpath->sdata;
 918        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 919        struct mesh_preq_queue *preq_node;
 920
 921        preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 922        if (!preq_node) {
 923                mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 924                return;
 925        }
 926
 927        spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 928        if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 929                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 930                kfree(preq_node);
 931                if (printk_ratelimit())
 932                        mhwmp_dbg(sdata, "PREQ node queue full\n");
 933                return;
 934        }
 935
 936        spin_lock(&mpath->state_lock);
 937        if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 938                spin_unlock(&mpath->state_lock);
 939                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 940                kfree(preq_node);
 941                return;
 942        }
 943
 944        memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 945        preq_node->flags = flags;
 946
 947        mpath->flags |= MESH_PATH_REQ_QUEUED;
 948        spin_unlock(&mpath->state_lock);
 949
 950        list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 951        ++ifmsh->preq_queue_len;
 952        spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 953
 954        if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 955                ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 956
 957        else if (time_before(jiffies, ifmsh->last_preq)) {
 958                /* avoid long wait if did not send preqs for a long time
 959                 * and jiffies wrapped around
 960                 */
 961                ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 962                ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 963        } else
 964                mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 965                                                min_preq_int_jiff(sdata));
 966}
 967
 968/**
 969 * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 970 *
 971 * @sdata: local mesh subif
 972 */
 973void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 974{
 975        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 976        struct mesh_preq_queue *preq_node;
 977        struct mesh_path *mpath;
 978        u8 ttl, target_flags;
 979        const u8 *da;
 980        u32 lifetime;
 981
 982        spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 983        if (!ifmsh->preq_queue_len ||
 984                time_before(jiffies, ifmsh->last_preq +
 985                                min_preq_int_jiff(sdata))) {
 986                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 987                return;
 988        }
 989
 990        preq_node = list_first_entry(&ifmsh->preq_queue.list,
 991                        struct mesh_preq_queue, list);
 992        list_del(&preq_node->list);
 993        --ifmsh->preq_queue_len;
 994        spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 995
 996        rcu_read_lock();
 997        mpath = mesh_path_lookup(preq_node->dst, sdata);
 998        if (!mpath)
 999                goto enddiscovery;
1000
1001        spin_lock_bh(&mpath->state_lock);
1002        mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1003        if (preq_node->flags & PREQ_Q_F_START) {
1004                if (mpath->flags & MESH_PATH_RESOLVING) {
1005                        spin_unlock_bh(&mpath->state_lock);
1006                        goto enddiscovery;
1007                } else {
1008                        mpath->flags &= ~MESH_PATH_RESOLVED;
1009                        mpath->flags |= MESH_PATH_RESOLVING;
1010                        mpath->discovery_retries = 0;
1011                        mpath->discovery_timeout = disc_timeout_jiff(sdata);
1012                }
1013        } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1014                        mpath->flags & MESH_PATH_RESOLVED) {
1015                mpath->flags &= ~MESH_PATH_RESOLVING;
1016                spin_unlock_bh(&mpath->state_lock);
1017                goto enddiscovery;
1018        }
1019
1020        ifmsh->last_preq = jiffies;
1021
1022        if (time_after(jiffies, ifmsh->last_sn_update +
1023                                net_traversal_jiffies(sdata)) ||
1024            time_before(jiffies, ifmsh->last_sn_update)) {
1025                ++ifmsh->sn;
1026                sdata->u.mesh.last_sn_update = jiffies;
1027        }
1028        lifetime = default_lifetime(sdata);
1029        ttl = sdata->u.mesh.mshcfg.element_ttl;
1030        if (ttl == 0) {
1031                sdata->u.mesh.mshstats.dropped_frames_ttl++;
1032                spin_unlock_bh(&mpath->state_lock);
1033                goto enddiscovery;
1034        }
1035
1036        if (preq_node->flags & PREQ_Q_F_REFRESH)
1037                target_flags = MP_F_DO;
1038        else
1039                target_flags = MP_F_RF;
1040
1041        spin_unlock_bh(&mpath->state_lock);
1042        da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1043        mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1044                        cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1045                        cpu_to_le32(mpath->sn), da, 0,
1046                        ttl, cpu_to_le32(lifetime), 0,
1047                        cpu_to_le32(ifmsh->preq_id++), sdata);
1048        mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1049
1050enddiscovery:
1051        rcu_read_unlock();
1052        kfree(preq_node);
1053}
1054
1055/**
1056 * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1057 *
1058 * @skb: 802.11 frame to be sent
1059 * @sdata: network subif the frame will be sent through
1060 *
1061 * Lookup next hop for given skb and start path discovery if no
1062 * forwarding information is found.
1063 *
1064 * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1065 * skb is freeed here if no mpath could be allocated.
1066 */
1067int mesh_nexthop_resolve(struct sk_buff *skb,
1068                         struct ieee80211_sub_if_data *sdata)
1069{
1070        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1071        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1072        struct mesh_path *mpath;
1073        struct sk_buff *skb_to_free = NULL;
1074        u8 *target_addr = hdr->addr3;
1075        int err = 0;
1076
1077        rcu_read_lock();
1078        err = mesh_nexthop_lookup(skb, sdata);
1079        if (!err)
1080                goto endlookup;
1081
1082        /* no nexthop found, start resolving */
1083        mpath = mesh_path_lookup(target_addr, sdata);
1084        if (!mpath) {
1085                mesh_path_add(target_addr, sdata);
1086                mpath = mesh_path_lookup(target_addr, sdata);
1087                if (!mpath) {
1088                        mesh_path_discard_frame(skb, sdata);
1089                        err = -ENOSPC;
1090                        goto endlookup;
1091                }
1092        }
1093
1094        if (!(mpath->flags & MESH_PATH_RESOLVING))
1095                mesh_queue_preq(mpath, PREQ_Q_F_START);
1096
1097        if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1098                skb_to_free = skb_dequeue(&mpath->frame_queue);
1099
1100        info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1101        ieee80211_set_qos_hdr(sdata, skb);
1102        skb_queue_tail(&mpath->frame_queue, skb);
1103        err = -ENOENT;
1104        if (skb_to_free)
1105                mesh_path_discard_frame(skb_to_free, sdata);
1106
1107endlookup:
1108        rcu_read_unlock();
1109        return err;
1110}
1111/**
1112 * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1113 * this function is considered "using" the associated mpath, so preempt a path
1114 * refresh if this mpath expires soon.
1115 *
1116 * @skb: 802.11 frame to be sent
1117 * @sdata: network subif the frame will be sent through
1118 *
1119 * Returns: 0 if the next hop was found. Nonzero otherwise.
1120 */
1121int mesh_nexthop_lookup(struct sk_buff *skb,
1122                        struct ieee80211_sub_if_data *sdata)
1123{
1124        struct mesh_path *mpath;
1125        struct sta_info *next_hop;
1126        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1127        u8 *target_addr = hdr->addr3;
1128        int err = -ENOENT;
1129
1130        rcu_read_lock();
1131        mpath = mesh_path_lookup(target_addr, sdata);
1132
1133        if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1134                goto endlookup;
1135
1136        if (time_after(jiffies,
1137                       mpath->exp_time -
1138                       msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1139            ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1140            !(mpath->flags & MESH_PATH_RESOLVING) &&
1141            !(mpath->flags & MESH_PATH_FIXED))
1142                mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1143
1144        next_hop = rcu_dereference(mpath->next_hop);
1145        if (next_hop) {
1146                memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1147                memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1148                err = 0;
1149        }
1150
1151endlookup:
1152        rcu_read_unlock();
1153        return err;
1154}
1155
1156void mesh_path_timer(unsigned long data)
1157{
1158        struct mesh_path *mpath = (void *) data;
1159        struct ieee80211_sub_if_data *sdata = mpath->sdata;
1160        int ret;
1161
1162        if (sdata->local->quiescing)
1163                return;
1164
1165        spin_lock_bh(&mpath->state_lock);
1166        if (mpath->flags & MESH_PATH_RESOLVED ||
1167                        (!(mpath->flags & MESH_PATH_RESOLVING))) {
1168                mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1169                spin_unlock_bh(&mpath->state_lock);
1170        } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1171                ++mpath->discovery_retries;
1172                mpath->discovery_timeout *= 2;
1173                mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1174                spin_unlock_bh(&mpath->state_lock);
1175                mesh_queue_preq(mpath, 0);
1176        } else {
1177                mpath->flags = 0;
1178                mpath->exp_time = jiffies;
1179                spin_unlock_bh(&mpath->state_lock);
1180                if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1181                        ret = mesh_path_send_to_gates(mpath);
1182                        if (ret)
1183                                mhwmp_dbg(sdata, "no gate was reachable\n");
1184                } else
1185                        mesh_path_flush_pending(mpath);
1186        }
1187}
1188
1189void
1190mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1191{
1192        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1193        u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1194        u8 flags, target_flags = 0;
1195
1196        flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1197                        ? RANN_FLAG_IS_GATE : 0;
1198
1199        switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1200        case IEEE80211_PROACTIVE_RANN:
1201                mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1202                               cpu_to_le32(++ifmsh->sn),
1203                               0, NULL, 0, broadcast_addr,
1204                               0, ifmsh->mshcfg.element_ttl,
1205                               cpu_to_le32(interval), 0, 0, sdata);
1206                break;
1207        case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1208                flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1209        case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1210                interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1211                target_flags |= IEEE80211_PREQ_TO_FLAG |
1212                                IEEE80211_PREQ_USN_FLAG;
1213                mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1214                                cpu_to_le32(++ifmsh->sn), target_flags,
1215                                (u8 *) broadcast_addr, 0, broadcast_addr,
1216                                0, ifmsh->mshcfg.element_ttl,
1217                                cpu_to_le32(interval),
1218                                0, cpu_to_le32(ifmsh->preq_id++), sdata);
1219                break;
1220        default:
1221                mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1222                return;
1223        }
1224}
1225
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