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        info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
 219        ieee80211_set_qos_hdr(sdata, skb);
 220}
 221
 222/**
 223 * mesh_send_path error - Sends a PERR mesh management frame
 224 *
 225 * @target: broken destination
 226 * @target_sn: SN of the broken destination
 227 * @target_rcode: reason code for this PERR
 228 * @ra: node this frame is addressed to
 229 *
 230 * Note: This function may be called with driver locks taken that the driver
 231 * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 232 * frame directly but add it to the pending queue instead.
 233 */
 234int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
 235                       __le16 target_rcode, const u8 *ra,
 236                       struct ieee80211_sub_if_data *sdata)
 237{
 238        struct ieee80211_local *local = sdata->local;
 239        struct sk_buff *skb;
 240        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 241        struct ieee80211_mgmt *mgmt;
 242        u8 *pos, ie_len;
 243        int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
 244                      sizeof(mgmt->u.action.u.mesh_action);
 245
 246        if (time_before(jiffies, ifmsh->next_perr))
 247                return -EAGAIN;
 248
 249        skb = dev_alloc_skb(local->tx_headroom +
 250                            IEEE80211_ENCRYPT_HEADROOM +
 251                            IEEE80211_ENCRYPT_TAILROOM +
 252                            hdr_len +
 253                            2 + 15 /* PERR IE */);
 254        if (!skb)
 255                return -1;
 256        skb_reserve(skb, local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM);
 257        mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
 258        memset(mgmt, 0, hdr_len);
 259        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 260                                          IEEE80211_STYPE_ACTION);
 261
 262        memcpy(mgmt->da, ra, ETH_ALEN);
 263        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 264        /* BSSID == SA */
 265        memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 266        mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 267        mgmt->u.action.u.mesh_action.action_code =
 268                                        WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 269        ie_len = 15;
 270        pos = skb_put(skb, 2 + ie_len);
 271        *pos++ = WLAN_EID_PERR;
 272        *pos++ = ie_len;
 273        /* ttl */
 274        *pos++ = ttl;
 275        /* number of destinations */
 276        *pos++ = 1;
 277        /*
 278         * flags bit, bit 1 is unset if we know the sequence number and
 279         * bit 2 is set if we have a reason code
 280         */
 281        *pos = 0;
 282        if (!target_sn)
 283                *pos |= MP_F_USN;
 284        if (target_rcode)
 285                *pos |= MP_F_RCODE;
 286        pos++;
 287        memcpy(pos, target, ETH_ALEN);
 288        pos += ETH_ALEN;
 289        memcpy(pos, &target_sn, 4);
 290        pos += 4;
 291        memcpy(pos, &target_rcode, 2);
 292
 293        /* see note in function header */
 294        prepare_frame_for_deferred_tx(sdata, skb);
 295        ifmsh->next_perr = TU_TO_EXP_TIME(
 296                                   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 297        ieee80211_add_pending_skb(local, skb);
 298        return 0;
 299}
 300
 301void ieee80211s_update_metric(struct ieee80211_local *local,
 302                struct sta_info *sta, struct sk_buff *skb)
 303{
 304        struct ieee80211_tx_info *txinfo = IEEE80211_SKB_CB(skb);
 305        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 306        int failed;
 307
 308        if (!ieee80211_is_data(hdr->frame_control))
 309                return;
 310
 311        failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 312
 313        /* moving average, scaled to 100 */
 314        sta->fail_avg = ((80 * sta->fail_avg + 5) / 100 + 20 * failed);
 315        if (sta->fail_avg > 95)
 316                mesh_plink_broken(sta);
 317}
 318
 319static u32 airtime_link_metric_get(struct ieee80211_local *local,
 320                                   struct sta_info *sta)
 321{
 322        struct rate_info rinfo;
 323        /* This should be adjusted for each device */
 324        int device_constant = 1 << ARITH_SHIFT;
 325        int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 326        int s_unit = 1 << ARITH_SHIFT;
 327        int rate, err;
 328        u32 tx_time, estimated_retx;
 329        u64 result;
 330
 331        if (sta->fail_avg >= 100)
 332                return MAX_METRIC;
 333
 334        sta_set_rate_info_tx(sta, &sta->last_tx_rate, &rinfo);
 335        rate = cfg80211_calculate_bitrate(&rinfo);
 336        if (WARN_ON(!rate))
 337                return MAX_METRIC;
 338
 339        err = (sta->fail_avg << ARITH_SHIFT) / 100;
 340
 341        /* bitrate is in units of 100 Kbps, while we need rate in units of
 342         * 1Mbps. This will be corrected on tx_time computation.
 343         */
 344        tx_time = (device_constant + 10 * test_frame_len / rate);
 345        estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 346        result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT) ;
 347        return (u32)result;
 348}
 349
 350/**
 351 * hwmp_route_info_get - Update routing info to originator and transmitter
 352 *
 353 * @sdata: local mesh subif
 354 * @mgmt: mesh management frame
 355 * @hwmp_ie: hwmp information element (PREP or PREQ)
 356 *
 357 * This function updates the path routing information to the originator and the
 358 * transmitter of a HWMP PREQ or PREP frame.
 359 *
 360 * Returns: metric to frame originator or 0 if the frame should not be further
 361 * processed
 362 *
 363 * Notes: this function is the only place (besides user-provided info) where
 364 * path routing information is updated.
 365 */
 366static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 367                            struct ieee80211_mgmt *mgmt,
 368                            u8 *hwmp_ie, enum mpath_frame_type action)
 369{
 370        struct ieee80211_local *local = sdata->local;
 371        struct mesh_path *mpath;
 372        struct sta_info *sta;
 373        bool fresh_info;
 374        u8 *orig_addr, *ta;
 375        u32 orig_sn, orig_metric;
 376        unsigned long orig_lifetime, exp_time;
 377        u32 last_hop_metric, new_metric;
 378        bool process = true;
 379
 380        rcu_read_lock();
 381        sta = sta_info_get(sdata, mgmt->sa);
 382        if (!sta) {
 383                rcu_read_unlock();
 384                return 0;
 385        }
 386
 387        last_hop_metric = airtime_link_metric_get(local, sta);
 388        /* Update and check originator routing info */
 389        fresh_info = true;
 390
 391        switch (action) {
 392        case MPATH_PREQ:
 393                orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 394                orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 395                orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 396                orig_metric = PREQ_IE_METRIC(hwmp_ie);
 397                break;
 398        case MPATH_PREP:
 399                /* Originator here refers to the MP that was the target in the
 400                 * Path Request. We divert from the nomenclature in the draft
 401                 * so that we can easily use a single function to gather path
 402                 * information from both PREQ and PREP frames.
 403                 */
 404                orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 405                orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 406                orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 407                orig_metric = PREP_IE_METRIC(hwmp_ie);
 408                break;
 409        default:
 410                rcu_read_unlock();
 411                return 0;
 412        }
 413        new_metric = orig_metric + last_hop_metric;
 414        if (new_metric < orig_metric)
 415                new_metric = MAX_METRIC;
 416        exp_time = TU_TO_EXP_TIME(orig_lifetime);
 417
 418        if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 419                /* This MP is the originator, we are not interested in this
 420                 * frame, except for updating transmitter's path info.
 421                 */
 422                process = false;
 423                fresh_info = false;
 424        } else {
 425                mpath = mesh_path_lookup(orig_addr, sdata);
 426                if (mpath) {
 427                        spin_lock_bh(&mpath->state_lock);
 428                        if (mpath->flags & MESH_PATH_FIXED)
 429                                fresh_info = false;
 430                        else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 431                            (mpath->flags & MESH_PATH_SN_VALID)) {
 432                                if (SN_GT(mpath->sn, orig_sn) ||
 433                                    (mpath->sn == orig_sn &&
 434                                     new_metric >= mpath->metric)) {
 435                                        process = false;
 436                                        fresh_info = false;
 437                                }
 438                        }
 439                } else {
 440                        mesh_path_add(orig_addr, sdata);
 441                        mpath = mesh_path_lookup(orig_addr, sdata);
 442                        if (!mpath) {
 443                                rcu_read_unlock();
 444                                return 0;
 445                        }
 446                        spin_lock_bh(&mpath->state_lock);
 447                }
 448
 449                if (fresh_info) {
 450                        mesh_path_assign_nexthop(mpath, sta);
 451                        mpath->flags |= MESH_PATH_SN_VALID;
 452                        mpath->metric = new_metric;
 453                        mpath->sn = orig_sn;
 454                        mpath->exp_time = time_after(mpath->exp_time, exp_time)
 455                                          ?  mpath->exp_time : exp_time;
 456                        mesh_path_activate(mpath);
 457                        spin_unlock_bh(&mpath->state_lock);
 458                        mesh_path_tx_pending(mpath);
 459                        /* draft says preq_id should be saved to, but there does
 460                         * not seem to be any use for it, skipping by now
 461                         */
 462                } else
 463                        spin_unlock_bh(&mpath->state_lock);
 464        }
 465
 466        /* Update and check transmitter routing info */
 467        ta = mgmt->sa;
 468        if (ether_addr_equal(orig_addr, ta))
 469                fresh_info = false;
 470        else {
 471                fresh_info = true;
 472
 473                mpath = mesh_path_lookup(ta, sdata);
 474                if (mpath) {
 475                        spin_lock_bh(&mpath->state_lock);
 476                        if ((mpath->flags & MESH_PATH_FIXED) ||
 477                                ((mpath->flags & MESH_PATH_ACTIVE) &&
 478                                        (last_hop_metric > mpath->metric)))
 479                                fresh_info = false;
 480                } else {
 481                        mesh_path_add(ta, sdata);
 482                        mpath = mesh_path_lookup(ta, sdata);
 483                        if (!mpath) {
 484                                rcu_read_unlock();
 485                                return 0;
 486                        }
 487                        spin_lock_bh(&mpath->state_lock);
 488                }
 489
 490                if (fresh_info) {
 491                        mesh_path_assign_nexthop(mpath, sta);
 492                        mpath->metric = last_hop_metric;
 493                        mpath->exp_time = time_after(mpath->exp_time, exp_time)
 494                                          ?  mpath->exp_time : exp_time;
 495                        mesh_path_activate(mpath);
 496                        spin_unlock_bh(&mpath->state_lock);
 497                        mesh_path_tx_pending(mpath);
 498                } else
 499                        spin_unlock_bh(&mpath->state_lock);
 500        }
 501
 502        rcu_read_unlock();
 503
 504        return process ? new_metric : 0;
 505}
 506
 507static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 508                                    struct ieee80211_mgmt *mgmt,
 509                                    u8 *preq_elem, u32 metric)
 510{
 511        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 512        struct mesh_path *mpath = NULL;
 513        u8 *target_addr, *orig_addr;
 514        const u8 *da;
 515        u8 target_flags, ttl, flags;
 516        u32 orig_sn, target_sn, lifetime, orig_metric;
 517        bool reply = false;
 518        bool forward = true;
 519        bool root_is_gate;
 520
 521        /* Update target SN, if present */
 522        target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 523        orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 524        target_sn = PREQ_IE_TARGET_SN(preq_elem);
 525        orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 526        target_flags = PREQ_IE_TARGET_F(preq_elem);
 527        orig_metric = metric;
 528        /* Proactive PREQ gate announcements */
 529        flags = PREQ_IE_FLAGS(preq_elem);
 530        root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 531
 532        mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 533
 534        if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 535                mhwmp_dbg(sdata, "PREQ is for us\n");
 536                forward = false;
 537                reply = true;
 538                metric = 0;
 539                if (time_after(jiffies, ifmsh->last_sn_update +
 540                                        net_traversal_jiffies(sdata)) ||
 541                    time_before(jiffies, ifmsh->last_sn_update)) {
 542                        target_sn = ++ifmsh->sn;
 543                        ifmsh->last_sn_update = jiffies;
 544                }
 545        } else if (is_broadcast_ether_addr(target_addr) &&
 546                   (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 547                rcu_read_lock();
 548                mpath = mesh_path_lookup(orig_addr, sdata);
 549                if (mpath) {
 550                        if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 551                                reply = true;
 552                                target_addr = sdata->vif.addr;
 553                                target_sn = ++ifmsh->sn;
 554                                metric = 0;
 555                                ifmsh->last_sn_update = jiffies;
 556                        }
 557                        if (root_is_gate)
 558                                mesh_path_add_gate(mpath);
 559                }
 560                rcu_read_unlock();
 561        } else {
 562                rcu_read_lock();
 563                mpath = mesh_path_lookup(target_addr, sdata);
 564                if (mpath) {
 565                        if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 566                                        SN_LT(mpath->sn, target_sn)) {
 567                                mpath->sn = target_sn;
 568                                mpath->flags |= MESH_PATH_SN_VALID;
 569                        } else if ((!(target_flags & MP_F_DO)) &&
 570                                        (mpath->flags & MESH_PATH_ACTIVE)) {
 571                                reply = true;
 572                                metric = mpath->metric;
 573                                target_sn = mpath->sn;
 574                                if (target_flags & MP_F_RF)
 575                                        target_flags |= MP_F_DO;
 576                                else
 577                                        forward = false;
 578                        }
 579                }
 580                rcu_read_unlock();
 581        }
 582
 583        if (reply) {
 584                lifetime = PREQ_IE_LIFETIME(preq_elem);
 585                ttl = ifmsh->mshcfg.element_ttl;
 586                if (ttl != 0) {
 587                        mhwmp_dbg(sdata, "replying to the PREQ\n");
 588                        mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 589                                cpu_to_le32(orig_sn), 0, target_addr,
 590                                cpu_to_le32(target_sn), mgmt->sa, 0, ttl,
 591                                cpu_to_le32(lifetime), cpu_to_le32(metric),
 592                                0, sdata);
 593                } else {
 594                        ifmsh->mshstats.dropped_frames_ttl++;
 595                }
 596        }
 597
 598        if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 599                u32 preq_id;
 600                u8 hopcount;
 601
 602                ttl = PREQ_IE_TTL(preq_elem);
 603                lifetime = PREQ_IE_LIFETIME(preq_elem);
 604                if (ttl <= 1) {
 605                        ifmsh->mshstats.dropped_frames_ttl++;
 606                        return;
 607                }
 608                mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 609                --ttl;
 610                preq_id = PREQ_IE_PREQ_ID(preq_elem);
 611                hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 612                da = (mpath && mpath->is_root) ?
 613                        mpath->rann_snd_addr : broadcast_addr;
 614
 615                if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 616                        target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 617                        target_sn = PREQ_IE_TARGET_SN(preq_elem);
 618                        metric = orig_metric;
 619                }
 620
 621                mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 622                                cpu_to_le32(orig_sn), target_flags, target_addr,
 623                                cpu_to_le32(target_sn), da,
 624                                hopcount, ttl, cpu_to_le32(lifetime),
 625                                cpu_to_le32(metric), cpu_to_le32(preq_id),
 626                                sdata);
 627                if (!is_multicast_ether_addr(da))
 628                        ifmsh->mshstats.fwded_unicast++;
 629                else
 630                        ifmsh->mshstats.fwded_mcast++;
 631                ifmsh->mshstats.fwded_frames++;
 632        }
 633}
 634
 635
 636static inline struct sta_info *
 637next_hop_deref_protected(struct mesh_path *mpath)
 638{
 639        return rcu_dereference_protected(mpath->next_hop,
 640                                         lockdep_is_held(&mpath->state_lock));
 641}
 642
 643
 644static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 645                                    struct ieee80211_mgmt *mgmt,
 646                                    u8 *prep_elem, u32 metric)
 647{
 648        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 649        struct mesh_path *mpath;
 650        u8 *target_addr, *orig_addr;
 651        u8 ttl, hopcount, flags;
 652        u8 next_hop[ETH_ALEN];
 653        u32 target_sn, orig_sn, lifetime;
 654
 655        mhwmp_dbg(sdata, "received PREP from %pM\n",
 656                  PREP_IE_ORIG_ADDR(prep_elem));
 657
 658        orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 659        if (ether_addr_equal(orig_addr, sdata->vif.addr))
 660                /* destination, no forwarding required */
 661                return;
 662
 663        if (!ifmsh->mshcfg.dot11MeshForwarding)
 664                return;
 665
 666        ttl = PREP_IE_TTL(prep_elem);
 667        if (ttl <= 1) {
 668                sdata->u.mesh.mshstats.dropped_frames_ttl++;
 669                return;
 670        }
 671
 672        rcu_read_lock();
 673        mpath = mesh_path_lookup(orig_addr, sdata);
 674        if (mpath)
 675                spin_lock_bh(&mpath->state_lock);
 676        else
 677                goto fail;
 678        if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 679                spin_unlock_bh(&mpath->state_lock);
 680                goto fail;
 681        }
 682        memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 683        spin_unlock_bh(&mpath->state_lock);
 684        --ttl;
 685        flags = PREP_IE_FLAGS(prep_elem);
 686        lifetime = PREP_IE_LIFETIME(prep_elem);
 687        hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 688        target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 689        target_sn = PREP_IE_TARGET_SN(prep_elem);
 690        orig_sn = PREP_IE_ORIG_SN(prep_elem);
 691
 692        mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr,
 693                cpu_to_le32(orig_sn), 0, target_addr,
 694                cpu_to_le32(target_sn), next_hop, hopcount,
 695                ttl, cpu_to_le32(lifetime), cpu_to_le32(metric),
 696                0, sdata);
 697        rcu_read_unlock();
 698
 699        sdata->u.mesh.mshstats.fwded_unicast++;
 700        sdata->u.mesh.mshstats.fwded_frames++;
 701        return;
 702
 703fail:
 704        rcu_read_unlock();
 705        sdata->u.mesh.mshstats.dropped_frames_no_route++;
 706}
 707
 708static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 709                             struct ieee80211_mgmt *mgmt, u8 *perr_elem)
 710{
 711        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 712        struct mesh_path *mpath;
 713        u8 ttl;
 714        u8 *ta, *target_addr;
 715        u32 target_sn;
 716        u16 target_rcode;
 717
 718        ta = mgmt->sa;
 719        ttl = PERR_IE_TTL(perr_elem);
 720        if (ttl <= 1) {
 721                ifmsh->mshstats.dropped_frames_ttl++;
 722                return;
 723        }
 724        ttl--;
 725        target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 726        target_sn = PERR_IE_TARGET_SN(perr_elem);
 727        target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 728
 729        rcu_read_lock();
 730        mpath = mesh_path_lookup(target_addr, sdata);
 731        if (mpath) {
 732                struct sta_info *sta;
 733
 734                spin_lock_bh(&mpath->state_lock);
 735                sta = next_hop_deref_protected(mpath);
 736                if (mpath->flags & MESH_PATH_ACTIVE &&
 737                    ether_addr_equal(ta, sta->sta.addr) &&
 738                    (!(mpath->flags & MESH_PATH_SN_VALID) ||
 739                    SN_GT(target_sn, mpath->sn))) {
 740                        mpath->flags &= ~MESH_PATH_ACTIVE;
 741                        mpath->sn = target_sn;
 742                        spin_unlock_bh(&mpath->state_lock);
 743                        if (!ifmsh->mshcfg.dot11MeshForwarding)
 744                                goto endperr;
 745                        mesh_path_error_tx(ttl, target_addr, cpu_to_le32(target_sn),
 746                                           cpu_to_le16(target_rcode),
 747                                           broadcast_addr, sdata);
 748                } else
 749                        spin_unlock_bh(&mpath->state_lock);
 750        }
 751endperr:
 752        rcu_read_unlock();
 753}
 754
 755static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 756                                struct ieee80211_mgmt *mgmt,
 757                                struct ieee80211_rann_ie *rann)
 758{
 759        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 760        struct ieee80211_local *local = sdata->local;
 761        struct sta_info *sta;
 762        struct mesh_path *mpath;
 763        u8 ttl, flags, hopcount;
 764        u8 *orig_addr;
 765        u32 orig_sn, metric, metric_txsta, interval;
 766        bool root_is_gate;
 767
 768        ttl = rann->rann_ttl;
 769        flags = rann->rann_flags;
 770        root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 771        orig_addr = rann->rann_addr;
 772        orig_sn = le32_to_cpu(rann->rann_seq);
 773        interval = le32_to_cpu(rann->rann_interval);
 774        hopcount = rann->rann_hopcount;
 775        hopcount++;
 776        metric = le32_to_cpu(rann->rann_metric);
 777
 778        /*  Ignore our own RANNs */
 779        if (ether_addr_equal(orig_addr, sdata->vif.addr))
 780                return;
 781
 782        mhwmp_dbg(sdata,
 783                  "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 784                  orig_addr, mgmt->sa, root_is_gate);
 785
 786        rcu_read_lock();
 787        sta = sta_info_get(sdata, mgmt->sa);
 788        if (!sta) {
 789                rcu_read_unlock();
 790                return;
 791        }
 792
 793        metric_txsta = airtime_link_metric_get(local, sta);
 794
 795        mpath = mesh_path_lookup(orig_addr, sdata);
 796        if (!mpath) {
 797                mesh_path_add(orig_addr, sdata);
 798                mpath = mesh_path_lookup(orig_addr, sdata);
 799                if (!mpath) {
 800                        rcu_read_unlock();
 801                        sdata->u.mesh.mshstats.dropped_frames_no_route++;
 802                        return;
 803                }
 804        }
 805
 806        if (!(SN_LT(mpath->sn, orig_sn)) &&
 807            !(mpath->sn == orig_sn && metric < mpath->rann_metric)) {
 808                rcu_read_unlock();
 809                return;
 810        }
 811
 812        if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 813             (time_after(jiffies, mpath->last_preq_to_root +
 814                                  root_path_confirmation_jiffies(sdata)) ||
 815             time_before(jiffies, mpath->last_preq_to_root))) &&
 816             !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 817                mhwmp_dbg(sdata,
 818                          "time to refresh root mpath %pM\n",
 819                          orig_addr);
 820                mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 821                mpath->last_preq_to_root = jiffies;
 822        }
 823
 824        mpath->sn = orig_sn;
 825        mpath->rann_metric = metric + metric_txsta;
 826        mpath->is_root = true;
 827        /* Recording RANNs sender address to send individually
 828         * addressed PREQs destined for root mesh STA */
 829        memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 830
 831        if (root_is_gate)
 832                mesh_path_add_gate(mpath);
 833
 834        if (ttl <= 1) {
 835                ifmsh->mshstats.dropped_frames_ttl++;
 836                rcu_read_unlock();
 837                return;
 838        }
 839        ttl--;
 840
 841        if (ifmsh->mshcfg.dot11MeshForwarding) {
 842                mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 843                                       cpu_to_le32(orig_sn),
 844                                       0, NULL, 0, broadcast_addr,
 845                                       hopcount, ttl, cpu_to_le32(interval),
 846                                       cpu_to_le32(metric + metric_txsta),
 847                                       0, sdata);
 848        }
 849
 850        rcu_read_unlock();
 851}
 852
 853
 854void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 855                            struct ieee80211_mgmt *mgmt,
 856                            size_t len)
 857{
 858        struct ieee802_11_elems elems;
 859        size_t baselen;
 860        u32 last_hop_metric;
 861        struct sta_info *sta;
 862
 863        /* need action_code */
 864        if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 865                return;
 866
 867        rcu_read_lock();
 868        sta = sta_info_get(sdata, mgmt->sa);
 869        if (!sta || sta->plink_state != NL80211_PLINK_ESTAB) {
 870                rcu_read_unlock();
 871                return;
 872        }
 873        rcu_read_unlock();
 874
 875        baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 876        ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 877                        len - baselen, &elems);
 878
 879        if (elems.preq) {
 880                if (elems.preq_len != 37)
 881                        /* Right now we support just 1 destination and no AE */
 882                        return;
 883                last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 884                                                      MPATH_PREQ);
 885                if (last_hop_metric)
 886                        hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 887                                                last_hop_metric);
 888        }
 889        if (elems.prep) {
 890                if (elems.prep_len != 31)
 891                        /* Right now we support no AE */
 892                        return;
 893                last_hop_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 894                                                      MPATH_PREP);
 895                if (last_hop_metric)
 896                        hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 897                                                last_hop_metric);
 898        }
 899        if (elems.perr) {
 900                if (elems.perr_len != 15)
 901                        /* Right now we support only one destination per PERR */
 902                        return;
 903                hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 904        }
 905        if (elems.rann)
 906                hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 907}
 908
 909/**
 910 * mesh_queue_preq - queue a PREQ to a given destination
 911 *
 912 * @mpath: mesh path to discover
 913 * @flags: special attributes of the PREQ to be sent
 914 *
 915 * Locking: the function must be called from within a rcu read lock block.
 916 *
 917 */
 918static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 919{
 920        struct ieee80211_sub_if_data *sdata = mpath->sdata;
 921        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 922        struct mesh_preq_queue *preq_node;
 923
 924        preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 925        if (!preq_node) {
 926                mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 927                return;
 928        }
 929
 930        spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 931        if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 932                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 933                kfree(preq_node);
 934                if (printk_ratelimit())
 935                        mhwmp_dbg(sdata, "PREQ node queue full\n");
 936                return;
 937        }
 938
 939        spin_lock(&mpath->state_lock);
 940        if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 941                spin_unlock(&mpath->state_lock);
 942                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 943                kfree(preq_node);
 944                return;
 945        }
 946
 947        memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
 948        preq_node->flags = flags;
 949
 950        mpath->flags |= MESH_PATH_REQ_QUEUED;
 951        spin_unlock(&mpath->state_lock);
 952
 953        list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
 954        ++ifmsh->preq_queue_len;
 955        spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 956
 957        if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
 958                ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 959
 960        else if (time_before(jiffies, ifmsh->last_preq)) {
 961                /* avoid long wait if did not send preqs for a long time
 962                 * and jiffies wrapped around
 963                 */
 964                ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
 965                ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 966        } else
 967                mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
 968                                                min_preq_int_jiff(sdata));
 969}
 970
 971/**
 972 * mesh_path_start_discovery - launch a path discovery from the PREQ queue
 973 *
 974 * @sdata: local mesh subif
 975 */
 976void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
 977{
 978        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 979        struct mesh_preq_queue *preq_node;
 980        struct mesh_path *mpath;
 981        u8 ttl, target_flags;
 982        const u8 *da;
 983        u32 lifetime;
 984
 985        spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 986        if (!ifmsh->preq_queue_len ||
 987                time_before(jiffies, ifmsh->last_preq +
 988                                min_preq_int_jiff(sdata))) {
 989                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 990                return;
 991        }
 992
 993        preq_node = list_first_entry(&ifmsh->preq_queue.list,
 994                        struct mesh_preq_queue, list);
 995        list_del(&preq_node->list);
 996        --ifmsh->preq_queue_len;
 997        spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 998
 999        rcu_read_lock();
1000        mpath = mesh_path_lookup(preq_node->dst, sdata);
1001        if (!mpath)
1002                goto enddiscovery;
1003
1004        spin_lock_bh(&mpath->state_lock);
1005        mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1006        if (preq_node->flags & PREQ_Q_F_START) {
1007                if (mpath->flags & MESH_PATH_RESOLVING) {
1008                        spin_unlock_bh(&mpath->state_lock);
1009                        goto enddiscovery;
1010                } else {
1011                        mpath->flags &= ~MESH_PATH_RESOLVED;
1012                        mpath->flags |= MESH_PATH_RESOLVING;
1013                        mpath->discovery_retries = 0;
1014                        mpath->discovery_timeout = disc_timeout_jiff(sdata);
1015                }
1016        } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1017                        mpath->flags & MESH_PATH_RESOLVED) {
1018                mpath->flags &= ~MESH_PATH_RESOLVING;
1019                spin_unlock_bh(&mpath->state_lock);
1020                goto enddiscovery;
1021        }
1022
1023        ifmsh->last_preq = jiffies;
1024
1025        if (time_after(jiffies, ifmsh->last_sn_update +
1026                                net_traversal_jiffies(sdata)) ||
1027            time_before(jiffies, ifmsh->last_sn_update)) {
1028                ++ifmsh->sn;
1029                sdata->u.mesh.last_sn_update = jiffies;
1030        }
1031        lifetime = default_lifetime(sdata);
1032        ttl = sdata->u.mesh.mshcfg.element_ttl;
1033        if (ttl == 0) {
1034                sdata->u.mesh.mshstats.dropped_frames_ttl++;
1035                spin_unlock_bh(&mpath->state_lock);
1036                goto enddiscovery;
1037        }
1038
1039        if (preq_node->flags & PREQ_Q_F_REFRESH)
1040                target_flags = MP_F_DO;
1041        else
1042                target_flags = MP_F_RF;
1043
1044        spin_unlock_bh(&mpath->state_lock);
1045        da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1046        mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr,
1047                        cpu_to_le32(ifmsh->sn), target_flags, mpath->dst,
1048                        cpu_to_le32(mpath->sn), da, 0,
1049                        ttl, cpu_to_le32(lifetime), 0,
1050                        cpu_to_le32(ifmsh->preq_id++), sdata);
1051        mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1052
1053enddiscovery:
1054        rcu_read_unlock();
1055        kfree(preq_node);
1056}
1057
1058/**
1059 * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1060 *
1061 * @skb: 802.11 frame to be sent
1062 * @sdata: network subif the frame will be sent through
1063 *
1064 * Lookup next hop for given skb and start path discovery if no
1065 * forwarding information is found.
1066 *
1067 * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1068 * skb is freeed here if no mpath could be allocated.
1069 */
1070int mesh_nexthop_resolve(struct sk_buff *skb,
1071                         struct ieee80211_sub_if_data *sdata)
1072{
1073        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1074        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1075        struct mesh_path *mpath;
1076        struct sk_buff *skb_to_free = NULL;
1077        u8 *target_addr = hdr->addr3;
1078        int err = 0;
1079
1080        rcu_read_lock();
1081        err = mesh_nexthop_lookup(skb, sdata);
1082        if (!err)
1083                goto endlookup;
1084
1085        /* no nexthop found, start resolving */
1086        mpath = mesh_path_lookup(target_addr, sdata);
1087        if (!mpath) {
1088                mesh_path_add(target_addr, sdata);
1089                mpath = mesh_path_lookup(target_addr, sdata);
1090                if (!mpath) {
1091                        mesh_path_discard_frame(skb, sdata);
1092                        err = -ENOSPC;
1093                        goto endlookup;
1094                }
1095        }
1096
1097        if (!(mpath->flags & MESH_PATH_RESOLVING))
1098                mesh_queue_preq(mpath, PREQ_Q_F_START);
1099
1100        if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1101                skb_to_free = skb_dequeue(&mpath->frame_queue);
1102
1103        info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
1104        ieee80211_set_qos_hdr(sdata, skb);
1105        skb_queue_tail(&mpath->frame_queue, skb);
1106        err = -ENOENT;
1107        if (skb_to_free)
1108                mesh_path_discard_frame(skb_to_free, sdata);
1109
1110endlookup:
1111        rcu_read_unlock();
1112        return err;
1113}
1114/**
1115 * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1116 * this function is considered "using" the associated mpath, so preempt a path
1117 * refresh if this mpath expires soon.
1118 *
1119 * @skb: 802.11 frame to be sent
1120 * @sdata: network subif the frame will be sent through
1121 *
1122 * Returns: 0 if the next hop was found. Nonzero otherwise.
1123 */
1124int mesh_nexthop_lookup(struct sk_buff *skb,
1125                        struct ieee80211_sub_if_data *sdata)
1126{
1127        struct mesh_path *mpath;
1128        struct sta_info *next_hop;
1129        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1130        u8 *target_addr = hdr->addr3;
1131        int err = -ENOENT;
1132
1133        rcu_read_lock();
1134        mpath = mesh_path_lookup(target_addr, sdata);
1135
1136        if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1137                goto endlookup;
1138
1139        if (time_after(jiffies,
1140                       mpath->exp_time -
1141                       msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1142            ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1143            !(mpath->flags & MESH_PATH_RESOLVING) &&
1144            !(mpath->flags & MESH_PATH_FIXED))
1145                mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1146
1147        next_hop = rcu_dereference(mpath->next_hop);
1148        if (next_hop) {
1149                memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1150                memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1151                err = 0;
1152        }
1153
1154endlookup:
1155        rcu_read_unlock();
1156        return err;
1157}
1158
1159void mesh_path_timer(unsigned long data)
1160{
1161        struct mesh_path *mpath = (void *) data;
1162        struct ieee80211_sub_if_data *sdata = mpath->sdata;
1163        int ret;
1164
1165        if (sdata->local->quiescing)
1166                return;
1167
1168        spin_lock_bh(&mpath->state_lock);
1169        if (mpath->flags & MESH_PATH_RESOLVED ||
1170                        (!(mpath->flags & MESH_PATH_RESOLVING))) {
1171                mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1172                spin_unlock_bh(&mpath->state_lock);
1173        } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1174                ++mpath->discovery_retries;
1175                mpath->discovery_timeout *= 2;
1176                mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1177                spin_unlock_bh(&mpath->state_lock);
1178                mesh_queue_preq(mpath, 0);
1179        } else {
1180                mpath->flags = 0;
1181                mpath->exp_time = jiffies;
1182                spin_unlock_bh(&mpath->state_lock);
1183                if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1184                        ret = mesh_path_send_to_gates(mpath);
1185                        if (ret)
1186                                mhwmp_dbg(sdata, "no gate was reachable\n");
1187                } else
1188                        mesh_path_flush_pending(mpath);
1189        }
1190}
1191
1192void
1193mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1194{
1195        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1196        u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1197        u8 flags, target_flags = 0;
1198
1199        flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1200                        ? RANN_FLAG_IS_GATE : 0;
1201
1202        switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1203        case IEEE80211_PROACTIVE_RANN:
1204                mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1205                               cpu_to_le32(++ifmsh->sn),
1206                               0, NULL, 0, broadcast_addr,
1207                               0, ifmsh->mshcfg.element_ttl,
1208                               cpu_to_le32(interval), 0, 0, sdata);
1209                break;
1210        case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1211                flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1212        case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1213                interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1214                target_flags |= IEEE80211_PREQ_TO_FLAG |
1215                                IEEE80211_PREQ_USN_FLAG;
1216                mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1217                                cpu_to_le32(++ifmsh->sn), target_flags,
1218                                (u8 *) broadcast_addr, 0, broadcast_addr,
1219                                0, ifmsh->mshcfg.element_ttl,
1220                                cpu_to_le32(interval),
1221                                0, cpu_to_le32(ifmsh->preq_id++), sdata);
1222                break;
1223        default:
1224                mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1225                return;
1226        }
1227}
1228