linux/net/mac80211/mesh_hwmp.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (c) 2008, 2009 open80211s Ltd.
   4 * Copyright (C) 2019 Intel Corporation
   5 * Author:     Luis Carlos Cobo <luisca@cozybit.com>
   6 */
   7
   8#include <linux/slab.h>
   9#include <linux/etherdevice.h>
  10#include <asm/unaligned.h>
  11#include "wme.h"
  12#include "mesh.h"
  13
  14#define TEST_FRAME_LEN  8192
  15#define MAX_METRIC      0xffffffff
  16#define ARITH_SHIFT     8
  17#define LINK_FAIL_THRESH 95
  18
  19#define MAX_PREQ_QUEUE_LEN      64
  20
  21static void mesh_queue_preq(struct mesh_path *, u8);
  22
  23static inline u32 u32_field_get(const u8 *preq_elem, int offset, bool ae)
  24{
  25        if (ae)
  26                offset += 6;
  27        return get_unaligned_le32(preq_elem + offset);
  28}
  29
  30static inline u16 u16_field_get(const u8 *preq_elem, int offset, bool ae)
  31{
  32        if (ae)
  33                offset += 6;
  34        return get_unaligned_le16(preq_elem + offset);
  35}
  36
  37/* HWMP IE processing macros */
  38#define AE_F                    (1<<6)
  39#define AE_F_SET(x)             (*x & AE_F)
  40#define PREQ_IE_FLAGS(x)        (*(x))
  41#define PREQ_IE_HOPCOUNT(x)     (*(x + 1))
  42#define PREQ_IE_TTL(x)          (*(x + 2))
  43#define PREQ_IE_PREQ_ID(x)      u32_field_get(x, 3, 0)
  44#define PREQ_IE_ORIG_ADDR(x)    (x + 7)
  45#define PREQ_IE_ORIG_SN(x)      u32_field_get(x, 13, 0)
  46#define PREQ_IE_LIFETIME(x)     u32_field_get(x, 17, AE_F_SET(x))
  47#define PREQ_IE_METRIC(x)       u32_field_get(x, 21, AE_F_SET(x))
  48#define PREQ_IE_TARGET_F(x)     (*(AE_F_SET(x) ? x + 32 : x + 26))
  49#define PREQ_IE_TARGET_ADDR(x)  (AE_F_SET(x) ? x + 33 : x + 27)
  50#define PREQ_IE_TARGET_SN(x)    u32_field_get(x, 33, AE_F_SET(x))
  51
  52
  53#define PREP_IE_FLAGS(x)        PREQ_IE_FLAGS(x)
  54#define PREP_IE_HOPCOUNT(x)     PREQ_IE_HOPCOUNT(x)
  55#define PREP_IE_TTL(x)          PREQ_IE_TTL(x)
  56#define PREP_IE_ORIG_ADDR(x)    (AE_F_SET(x) ? x + 27 : x + 21)
  57#define PREP_IE_ORIG_SN(x)      u32_field_get(x, 27, AE_F_SET(x))
  58#define PREP_IE_LIFETIME(x)     u32_field_get(x, 13, AE_F_SET(x))
  59#define PREP_IE_METRIC(x)       u32_field_get(x, 17, AE_F_SET(x))
  60#define PREP_IE_TARGET_ADDR(x)  (x + 3)
  61#define PREP_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  62
  63#define PERR_IE_TTL(x)          (*(x))
  64#define PERR_IE_TARGET_FLAGS(x) (*(x + 2))
  65#define PERR_IE_TARGET_ADDR(x)  (x + 3)
  66#define PERR_IE_TARGET_SN(x)    u32_field_get(x, 9, 0)
  67#define PERR_IE_TARGET_RCODE(x) u16_field_get(x, 13, 0)
  68
  69#define MSEC_TO_TU(x) (x*1000/1024)
  70#define SN_GT(x, y) ((s32)(y - x) < 0)
  71#define SN_LT(x, y) ((s32)(x - y) < 0)
  72#define MAX_SANE_SN_DELTA 32
  73
  74static inline u32 SN_DELTA(u32 x, u32 y)
  75{
  76        return x >= y ? x - y : y - x;
  77}
  78
  79#define net_traversal_jiffies(s) \
  80        msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPnetDiameterTraversalTime)
  81#define default_lifetime(s) \
  82        MSEC_TO_TU(s->u.mesh.mshcfg.dot11MeshHWMPactivePathTimeout)
  83#define min_preq_int_jiff(s) \
  84        (msecs_to_jiffies(s->u.mesh.mshcfg.dot11MeshHWMPpreqMinInterval))
  85#define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
  86#define disc_timeout_jiff(s) \
  87        msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
  88#define root_path_confirmation_jiffies(s) \
  89        msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
  90
  91enum mpath_frame_type {
  92        MPATH_PREQ = 0,
  93        MPATH_PREP,
  94        MPATH_PERR,
  95        MPATH_RANN
  96};
  97
  98static const u8 broadcast_addr[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
  99
 100static int mesh_path_sel_frame_tx(enum mpath_frame_type action, u8 flags,
 101                                  const u8 *orig_addr, u32 orig_sn,
 102                                  u8 target_flags, const u8 *target,
 103                                  u32 target_sn, const u8 *da,
 104                                  u8 hop_count, u8 ttl,
 105                                  u32 lifetime, u32 metric, u32 preq_id,
 106                                  struct ieee80211_sub_if_data *sdata)
 107{
 108        struct ieee80211_local *local = sdata->local;
 109        struct sk_buff *skb;
 110        struct ieee80211_mgmt *mgmt;
 111        u8 *pos, ie_len;
 112        int hdr_len = offsetofend(struct ieee80211_mgmt,
 113                                  u.action.u.mesh_action);
 114
 115        skb = dev_alloc_skb(local->tx_headroom +
 116                            hdr_len +
 117                            2 + 37); /* max HWMP IE */
 118        if (!skb)
 119                return -1;
 120        skb_reserve(skb, local->tx_headroom);
 121        mgmt = skb_put_zero(skb, hdr_len);
 122        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 123                                          IEEE80211_STYPE_ACTION);
 124
 125        memcpy(mgmt->da, da, ETH_ALEN);
 126        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 127        /* BSSID == SA */
 128        memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 129        mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 130        mgmt->u.action.u.mesh_action.action_code =
 131                                        WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 132
 133        switch (action) {
 134        case MPATH_PREQ:
 135                mhwmp_dbg(sdata, "sending PREQ to %pM\n", target);
 136                ie_len = 37;
 137                pos = skb_put(skb, 2 + ie_len);
 138                *pos++ = WLAN_EID_PREQ;
 139                break;
 140        case MPATH_PREP:
 141                mhwmp_dbg(sdata, "sending PREP to %pM\n", orig_addr);
 142                ie_len = 31;
 143                pos = skb_put(skb, 2 + ie_len);
 144                *pos++ = WLAN_EID_PREP;
 145                break;
 146        case MPATH_RANN:
 147                mhwmp_dbg(sdata, "sending RANN from %pM\n", orig_addr);
 148                ie_len = sizeof(struct ieee80211_rann_ie);
 149                pos = skb_put(skb, 2 + ie_len);
 150                *pos++ = WLAN_EID_RANN;
 151                break;
 152        default:
 153                kfree_skb(skb);
 154                return -ENOTSUPP;
 155        }
 156        *pos++ = ie_len;
 157        *pos++ = flags;
 158        *pos++ = hop_count;
 159        *pos++ = ttl;
 160        if (action == MPATH_PREP) {
 161                memcpy(pos, target, ETH_ALEN);
 162                pos += ETH_ALEN;
 163                put_unaligned_le32(target_sn, pos);
 164                pos += 4;
 165        } else {
 166                if (action == MPATH_PREQ) {
 167                        put_unaligned_le32(preq_id, pos);
 168                        pos += 4;
 169                }
 170                memcpy(pos, orig_addr, ETH_ALEN);
 171                pos += ETH_ALEN;
 172                put_unaligned_le32(orig_sn, pos);
 173                pos += 4;
 174        }
 175        put_unaligned_le32(lifetime, pos); /* interval for RANN */
 176        pos += 4;
 177        put_unaligned_le32(metric, pos);
 178        pos += 4;
 179        if (action == MPATH_PREQ) {
 180                *pos++ = 1; /* destination count */
 181                *pos++ = target_flags;
 182                memcpy(pos, target, ETH_ALEN);
 183                pos += ETH_ALEN;
 184                put_unaligned_le32(target_sn, pos);
 185                pos += 4;
 186        } else if (action == MPATH_PREP) {
 187                memcpy(pos, orig_addr, ETH_ALEN);
 188                pos += ETH_ALEN;
 189                put_unaligned_le32(orig_sn, pos);
 190                pos += 4;
 191        }
 192
 193        ieee80211_tx_skb(sdata, skb);
 194        return 0;
 195}
 196
 197
 198/*  Headroom is not adjusted.  Caller should ensure that skb has sufficient
 199 *  headroom in case the frame is encrypted. */
 200static void prepare_frame_for_deferred_tx(struct ieee80211_sub_if_data *sdata,
 201                struct sk_buff *skb)
 202{
 203        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 204        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 205
 206        skb_reset_mac_header(skb);
 207        skb_reset_network_header(skb);
 208        skb_reset_transport_header(skb);
 209
 210        /* Send all internal mgmt frames on VO. Accordingly set TID to 7. */
 211        skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 212        skb->priority = 7;
 213
 214        info->control.vif = &sdata->vif;
 215        info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
 216        ieee80211_set_qos_hdr(sdata, skb);
 217        ieee80211_mps_set_frame_flags(sdata, NULL, hdr);
 218}
 219
 220/**
 221 * mesh_path_error_tx - Sends a PERR mesh management frame
 222 *
 223 * @ttl: allowed remaining hops
 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 * @sdata: local mesh subif
 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(struct ieee80211_sub_if_data *sdata,
 235                       u8 ttl, const u8 *target, u32 target_sn,
 236                       u16 target_rcode, const u8 *ra)
 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 = offsetofend(struct ieee80211_mgmt,
 244                                  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                            sdata->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 + sdata->encrypt_headroom);
 257        mgmt = skb_put_zero(skb, hdr_len);
 258        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 259                                          IEEE80211_STYPE_ACTION);
 260
 261        memcpy(mgmt->da, ra, ETH_ALEN);
 262        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 263        /* BSSID == SA */
 264        memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
 265        mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
 266        mgmt->u.action.u.mesh_action.action_code =
 267                                        WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
 268        ie_len = 15;
 269        pos = skb_put(skb, 2 + ie_len);
 270        *pos++ = WLAN_EID_PERR;
 271        *pos++ = ie_len;
 272        /* ttl */
 273        *pos++ = ttl;
 274        /* number of destinations */
 275        *pos++ = 1;
 276        /* Flags field has AE bit only as defined in
 277         * sec 8.4.2.117 IEEE802.11-2012
 278         */
 279        *pos = 0;
 280        pos++;
 281        memcpy(pos, target, ETH_ALEN);
 282        pos += ETH_ALEN;
 283        put_unaligned_le32(target_sn, pos);
 284        pos += 4;
 285        put_unaligned_le16(target_rcode, pos);
 286
 287        /* see note in function header */
 288        prepare_frame_for_deferred_tx(sdata, skb);
 289        ifmsh->next_perr = TU_TO_EXP_TIME(
 290                                   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
 291        ieee80211_add_pending_skb(local, skb);
 292        return 0;
 293}
 294
 295void ieee80211s_update_metric(struct ieee80211_local *local,
 296                              struct sta_info *sta,
 297                              struct ieee80211_tx_status *st)
 298{
 299        struct ieee80211_tx_info *txinfo = st->info;
 300        int failed;
 301        struct rate_info rinfo;
 302
 303        failed = !(txinfo->flags & IEEE80211_TX_STAT_ACK);
 304
 305        /* moving average, scaled to 100.
 306         * feed failure as 100 and success as 0
 307         */
 308        ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, failed * 100);
 309        if (ewma_mesh_fail_avg_read(&sta->mesh->fail_avg) >
 310                        LINK_FAIL_THRESH)
 311                mesh_plink_broken(sta);
 312
 313        sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
 314        ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg,
 315                                  cfg80211_calculate_bitrate(&rinfo));
 316}
 317
 318u32 airtime_link_metric_get(struct ieee80211_local *local,
 319                            struct sta_info *sta)
 320{
 321        /* This should be adjusted for each device */
 322        int device_constant = 1 << ARITH_SHIFT;
 323        int test_frame_len = TEST_FRAME_LEN << ARITH_SHIFT;
 324        int s_unit = 1 << ARITH_SHIFT;
 325        int rate, err;
 326        u32 tx_time, estimated_retx;
 327        u64 result;
 328        unsigned long fail_avg =
 329                ewma_mesh_fail_avg_read(&sta->mesh->fail_avg);
 330
 331        if (sta->mesh->plink_state != NL80211_PLINK_ESTAB)
 332                return MAX_METRIC;
 333
 334        /* Try to get rate based on HW/SW RC algorithm.
 335         * Rate is returned in units of Kbps, correct this
 336         * to comply with airtime calculation units
 337         * Round up in case we get rate < 100Kbps
 338         */
 339        rate = DIV_ROUND_UP(sta_get_expected_throughput(sta), 100);
 340
 341        if (rate) {
 342                err = 0;
 343        } else {
 344                if (fail_avg > LINK_FAIL_THRESH)
 345                        return MAX_METRIC;
 346
 347                rate = ewma_mesh_tx_rate_avg_read(&sta->mesh->tx_rate_avg);
 348                if (WARN_ON(!rate))
 349                        return MAX_METRIC;
 350
 351                err = (fail_avg << ARITH_SHIFT) / 100;
 352        }
 353
 354        /* bitrate is in units of 100 Kbps, while we need rate in units of
 355         * 1Mbps. This will be corrected on tx_time computation.
 356         */
 357        tx_time = (device_constant + 10 * test_frame_len / rate);
 358        estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
 359        result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
 360        return (u32)result;
 361}
 362
 363/**
 364 * hwmp_route_info_get - Update routing info to originator and transmitter
 365 *
 366 * @sdata: local mesh subif
 367 * @mgmt: mesh management frame
 368 * @hwmp_ie: hwmp information element (PREP or PREQ)
 369 * @action: type of hwmp ie
 370 *
 371 * This function updates the path routing information to the originator and the
 372 * transmitter of a HWMP PREQ or PREP frame.
 373 *
 374 * Returns: metric to frame originator or 0 if the frame should not be further
 375 * processed
 376 *
 377 * Notes: this function is the only place (besides user-provided info) where
 378 * path routing information is updated.
 379 */
 380static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
 381                               struct ieee80211_mgmt *mgmt,
 382                               const u8 *hwmp_ie, enum mpath_frame_type action)
 383{
 384        struct ieee80211_local *local = sdata->local;
 385        struct mesh_path *mpath;
 386        struct sta_info *sta;
 387        bool fresh_info;
 388        const u8 *orig_addr, *ta;
 389        u32 orig_sn, orig_metric;
 390        unsigned long orig_lifetime, exp_time;
 391        u32 last_hop_metric, new_metric;
 392        bool process = true;
 393        u8 hopcount;
 394
 395        rcu_read_lock();
 396        sta = sta_info_get(sdata, mgmt->sa);
 397        if (!sta) {
 398                rcu_read_unlock();
 399                return 0;
 400        }
 401
 402        last_hop_metric = airtime_link_metric_get(local, sta);
 403        /* Update and check originator routing info */
 404        fresh_info = true;
 405
 406        switch (action) {
 407        case MPATH_PREQ:
 408                orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
 409                orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
 410                orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
 411                orig_metric = PREQ_IE_METRIC(hwmp_ie);
 412                hopcount = PREQ_IE_HOPCOUNT(hwmp_ie) + 1;
 413                break;
 414        case MPATH_PREP:
 415                /* Originator here refers to the MP that was the target in the
 416                 * Path Request. We divert from the nomenclature in the draft
 417                 * so that we can easily use a single function to gather path
 418                 * information from both PREQ and PREP frames.
 419                 */
 420                orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
 421                orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
 422                orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
 423                orig_metric = PREP_IE_METRIC(hwmp_ie);
 424                hopcount = PREP_IE_HOPCOUNT(hwmp_ie) + 1;
 425                break;
 426        default:
 427                rcu_read_unlock();
 428                return 0;
 429        }
 430        new_metric = orig_metric + last_hop_metric;
 431        if (new_metric < orig_metric)
 432                new_metric = MAX_METRIC;
 433        exp_time = TU_TO_EXP_TIME(orig_lifetime);
 434
 435        if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
 436                /* This MP is the originator, we are not interested in this
 437                 * frame, except for updating transmitter's path info.
 438                 */
 439                process = false;
 440                fresh_info = false;
 441        } else {
 442                mpath = mesh_path_lookup(sdata, orig_addr);
 443                if (mpath) {
 444                        spin_lock_bh(&mpath->state_lock);
 445                        if (mpath->flags & MESH_PATH_FIXED)
 446                                fresh_info = false;
 447                        else if ((mpath->flags & MESH_PATH_ACTIVE) &&
 448                            (mpath->flags & MESH_PATH_SN_VALID)) {
 449                                if (SN_GT(mpath->sn, orig_sn) ||
 450                                    (mpath->sn == orig_sn &&
 451                                     (rcu_access_pointer(mpath->next_hop) !=
 452                                                      sta ?
 453                                              mult_frac(new_metric, 10, 9) :
 454                                              new_metric) >= mpath->metric)) {
 455                                        process = false;
 456                                        fresh_info = false;
 457                                }
 458                        } else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 459                                bool have_sn, newer_sn, bounced;
 460
 461                                have_sn = mpath->flags & MESH_PATH_SN_VALID;
 462                                newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
 463                                bounced = have_sn &&
 464                                          (SN_DELTA(orig_sn, mpath->sn) >
 465                                                        MAX_SANE_SN_DELTA);
 466
 467                                if (!have_sn || newer_sn) {
 468                                        /* if SN is newer than what we had
 469                                         * then we can take it */;
 470                                } else if (bounced) {
 471                                        /* if SN is way different than what
 472                                         * we had then assume the other side
 473                                         * rebooted or restarted */;
 474                                } else {
 475                                        process = false;
 476                                        fresh_info = false;
 477                                }
 478                        }
 479                } else {
 480                        mpath = mesh_path_add(sdata, orig_addr);
 481                        if (IS_ERR(mpath)) {
 482                                rcu_read_unlock();
 483                                return 0;
 484                        }
 485                        spin_lock_bh(&mpath->state_lock);
 486                }
 487
 488                if (fresh_info) {
 489                        if (rcu_access_pointer(mpath->next_hop) != sta)
 490                                mpath->path_change_count++;
 491                        mesh_path_assign_nexthop(mpath, sta);
 492                        mpath->flags |= MESH_PATH_SN_VALID;
 493                        mpath->metric = new_metric;
 494                        mpath->sn = orig_sn;
 495                        mpath->exp_time = time_after(mpath->exp_time, exp_time)
 496                                          ?  mpath->exp_time : exp_time;
 497                        mpath->hop_count = hopcount;
 498                        mesh_path_activate(mpath);
 499                        spin_unlock_bh(&mpath->state_lock);
 500                        ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 501                        /* init it at a low value - 0 start is tricky */
 502                        ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 503                        mesh_path_tx_pending(mpath);
 504                        /* draft says preq_id should be saved to, but there does
 505                         * not seem to be any use for it, skipping by now
 506                         */
 507                } else
 508                        spin_unlock_bh(&mpath->state_lock);
 509        }
 510
 511        /* Update and check transmitter routing info */
 512        ta = mgmt->sa;
 513        if (ether_addr_equal(orig_addr, ta))
 514                fresh_info = false;
 515        else {
 516                fresh_info = true;
 517
 518                mpath = mesh_path_lookup(sdata, ta);
 519                if (mpath) {
 520                        spin_lock_bh(&mpath->state_lock);
 521                        if ((mpath->flags & MESH_PATH_FIXED) ||
 522                            ((mpath->flags & MESH_PATH_ACTIVE) &&
 523                             ((rcu_access_pointer(mpath->next_hop) != sta ?
 524                                       mult_frac(last_hop_metric, 10, 9) :
 525                                       last_hop_metric) > mpath->metric)))
 526                                fresh_info = false;
 527                } else {
 528                        mpath = mesh_path_add(sdata, ta);
 529                        if (IS_ERR(mpath)) {
 530                                rcu_read_unlock();
 531                                return 0;
 532                        }
 533                        spin_lock_bh(&mpath->state_lock);
 534                }
 535
 536                if (fresh_info) {
 537                        if (rcu_access_pointer(mpath->next_hop) != sta)
 538                                mpath->path_change_count++;
 539                        mesh_path_assign_nexthop(mpath, sta);
 540                        mpath->metric = last_hop_metric;
 541                        mpath->exp_time = time_after(mpath->exp_time, exp_time)
 542                                          ?  mpath->exp_time : exp_time;
 543                        mpath->hop_count = 1;
 544                        mesh_path_activate(mpath);
 545                        spin_unlock_bh(&mpath->state_lock);
 546                        ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
 547                        /* init it at a low value - 0 start is tricky */
 548                        ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
 549                        mesh_path_tx_pending(mpath);
 550                } else
 551                        spin_unlock_bh(&mpath->state_lock);
 552        }
 553
 554        rcu_read_unlock();
 555
 556        return process ? new_metric : 0;
 557}
 558
 559static void hwmp_preq_frame_process(struct ieee80211_sub_if_data *sdata,
 560                                    struct ieee80211_mgmt *mgmt,
 561                                    const u8 *preq_elem, u32 orig_metric)
 562{
 563        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 564        struct mesh_path *mpath = NULL;
 565        const u8 *target_addr, *orig_addr;
 566        const u8 *da;
 567        u8 target_flags, ttl, flags;
 568        u32 orig_sn, target_sn, lifetime, target_metric = 0;
 569        bool reply = false;
 570        bool forward = true;
 571        bool root_is_gate;
 572
 573        /* Update target SN, if present */
 574        target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 575        orig_addr = PREQ_IE_ORIG_ADDR(preq_elem);
 576        target_sn = PREQ_IE_TARGET_SN(preq_elem);
 577        orig_sn = PREQ_IE_ORIG_SN(preq_elem);
 578        target_flags = PREQ_IE_TARGET_F(preq_elem);
 579        /* Proactive PREQ gate announcements */
 580        flags = PREQ_IE_FLAGS(preq_elem);
 581        root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 582
 583        mhwmp_dbg(sdata, "received PREQ from %pM\n", orig_addr);
 584
 585        if (ether_addr_equal(target_addr, sdata->vif.addr)) {
 586                mhwmp_dbg(sdata, "PREQ is for us\n");
 587                forward = false;
 588                reply = true;
 589                target_metric = 0;
 590
 591                if (SN_GT(target_sn, ifmsh->sn))
 592                        ifmsh->sn = target_sn;
 593
 594                if (time_after(jiffies, ifmsh->last_sn_update +
 595                                        net_traversal_jiffies(sdata)) ||
 596                    time_before(jiffies, ifmsh->last_sn_update)) {
 597                        ++ifmsh->sn;
 598                        ifmsh->last_sn_update = jiffies;
 599                }
 600                target_sn = ifmsh->sn;
 601        } else if (is_broadcast_ether_addr(target_addr) &&
 602                   (target_flags & IEEE80211_PREQ_TO_FLAG)) {
 603                rcu_read_lock();
 604                mpath = mesh_path_lookup(sdata, orig_addr);
 605                if (mpath) {
 606                        if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 607                                reply = true;
 608                                target_addr = sdata->vif.addr;
 609                                target_sn = ++ifmsh->sn;
 610                                target_metric = 0;
 611                                ifmsh->last_sn_update = jiffies;
 612                        }
 613                        if (root_is_gate)
 614                                mesh_path_add_gate(mpath);
 615                }
 616                rcu_read_unlock();
 617        } else {
 618                rcu_read_lock();
 619                mpath = mesh_path_lookup(sdata, target_addr);
 620                if (mpath) {
 621                        if ((!(mpath->flags & MESH_PATH_SN_VALID)) ||
 622                                        SN_LT(mpath->sn, target_sn)) {
 623                                mpath->sn = target_sn;
 624                                mpath->flags |= MESH_PATH_SN_VALID;
 625                        } else if ((!(target_flags & IEEE80211_PREQ_TO_FLAG)) &&
 626                                        (mpath->flags & MESH_PATH_ACTIVE)) {
 627                                reply = true;
 628                                target_metric = mpath->metric;
 629                                target_sn = mpath->sn;
 630                                /* Case E2 of sec 13.10.9.3 IEEE 802.11-2012*/
 631                                target_flags |= IEEE80211_PREQ_TO_FLAG;
 632                        }
 633                }
 634                rcu_read_unlock();
 635        }
 636
 637        if (reply) {
 638                lifetime = PREQ_IE_LIFETIME(preq_elem);
 639                ttl = ifmsh->mshcfg.element_ttl;
 640                if (ttl != 0) {
 641                        mhwmp_dbg(sdata, "replying to the PREQ\n");
 642                        mesh_path_sel_frame_tx(MPATH_PREP, 0, orig_addr,
 643                                               orig_sn, 0, target_addr,
 644                                               target_sn, mgmt->sa, 0, ttl,
 645                                               lifetime, target_metric, 0,
 646                                               sdata);
 647                } else {
 648                        ifmsh->mshstats.dropped_frames_ttl++;
 649                }
 650        }
 651
 652        if (forward && ifmsh->mshcfg.dot11MeshForwarding) {
 653                u32 preq_id;
 654                u8 hopcount;
 655
 656                ttl = PREQ_IE_TTL(preq_elem);
 657                lifetime = PREQ_IE_LIFETIME(preq_elem);
 658                if (ttl <= 1) {
 659                        ifmsh->mshstats.dropped_frames_ttl++;
 660                        return;
 661                }
 662                mhwmp_dbg(sdata, "forwarding the PREQ from %pM\n", orig_addr);
 663                --ttl;
 664                preq_id = PREQ_IE_PREQ_ID(preq_elem);
 665                hopcount = PREQ_IE_HOPCOUNT(preq_elem) + 1;
 666                da = (mpath && mpath->is_root) ?
 667                        mpath->rann_snd_addr : broadcast_addr;
 668
 669                if (flags & IEEE80211_PREQ_PROACTIVE_PREP_FLAG) {
 670                        target_addr = PREQ_IE_TARGET_ADDR(preq_elem);
 671                        target_sn = PREQ_IE_TARGET_SN(preq_elem);
 672                }
 673
 674                mesh_path_sel_frame_tx(MPATH_PREQ, flags, orig_addr,
 675                                       orig_sn, target_flags, target_addr,
 676                                       target_sn, da, hopcount, ttl, lifetime,
 677                                       orig_metric, preq_id, sdata);
 678                if (!is_multicast_ether_addr(da))
 679                        ifmsh->mshstats.fwded_unicast++;
 680                else
 681                        ifmsh->mshstats.fwded_mcast++;
 682                ifmsh->mshstats.fwded_frames++;
 683        }
 684}
 685
 686
 687static inline struct sta_info *
 688next_hop_deref_protected(struct mesh_path *mpath)
 689{
 690        return rcu_dereference_protected(mpath->next_hop,
 691                                         lockdep_is_held(&mpath->state_lock));
 692}
 693
 694
 695static void hwmp_prep_frame_process(struct ieee80211_sub_if_data *sdata,
 696                                    struct ieee80211_mgmt *mgmt,
 697                                    const u8 *prep_elem, u32 metric)
 698{
 699        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 700        struct mesh_path *mpath;
 701        const u8 *target_addr, *orig_addr;
 702        u8 ttl, hopcount, flags;
 703        u8 next_hop[ETH_ALEN];
 704        u32 target_sn, orig_sn, lifetime;
 705
 706        mhwmp_dbg(sdata, "received PREP from %pM\n",
 707                  PREP_IE_TARGET_ADDR(prep_elem));
 708
 709        orig_addr = PREP_IE_ORIG_ADDR(prep_elem);
 710        if (ether_addr_equal(orig_addr, sdata->vif.addr))
 711                /* destination, no forwarding required */
 712                return;
 713
 714        if (!ifmsh->mshcfg.dot11MeshForwarding)
 715                return;
 716
 717        ttl = PREP_IE_TTL(prep_elem);
 718        if (ttl <= 1) {
 719                sdata->u.mesh.mshstats.dropped_frames_ttl++;
 720                return;
 721        }
 722
 723        rcu_read_lock();
 724        mpath = mesh_path_lookup(sdata, orig_addr);
 725        if (mpath)
 726                spin_lock_bh(&mpath->state_lock);
 727        else
 728                goto fail;
 729        if (!(mpath->flags & MESH_PATH_ACTIVE)) {
 730                spin_unlock_bh(&mpath->state_lock);
 731                goto fail;
 732        }
 733        memcpy(next_hop, next_hop_deref_protected(mpath)->sta.addr, ETH_ALEN);
 734        spin_unlock_bh(&mpath->state_lock);
 735        --ttl;
 736        flags = PREP_IE_FLAGS(prep_elem);
 737        lifetime = PREP_IE_LIFETIME(prep_elem);
 738        hopcount = PREP_IE_HOPCOUNT(prep_elem) + 1;
 739        target_addr = PREP_IE_TARGET_ADDR(prep_elem);
 740        target_sn = PREP_IE_TARGET_SN(prep_elem);
 741        orig_sn = PREP_IE_ORIG_SN(prep_elem);
 742
 743        mesh_path_sel_frame_tx(MPATH_PREP, flags, orig_addr, orig_sn, 0,
 744                               target_addr, target_sn, next_hop, hopcount,
 745                               ttl, lifetime, metric, 0, sdata);
 746        rcu_read_unlock();
 747
 748        sdata->u.mesh.mshstats.fwded_unicast++;
 749        sdata->u.mesh.mshstats.fwded_frames++;
 750        return;
 751
 752fail:
 753        rcu_read_unlock();
 754        sdata->u.mesh.mshstats.dropped_frames_no_route++;
 755}
 756
 757static void hwmp_perr_frame_process(struct ieee80211_sub_if_data *sdata,
 758                                    struct ieee80211_mgmt *mgmt,
 759                                    const u8 *perr_elem)
 760{
 761        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 762        struct mesh_path *mpath;
 763        u8 ttl;
 764        const u8 *ta, *target_addr;
 765        u32 target_sn;
 766        u16 target_rcode;
 767
 768        ta = mgmt->sa;
 769        ttl = PERR_IE_TTL(perr_elem);
 770        if (ttl <= 1) {
 771                ifmsh->mshstats.dropped_frames_ttl++;
 772                return;
 773        }
 774        ttl--;
 775        target_addr = PERR_IE_TARGET_ADDR(perr_elem);
 776        target_sn = PERR_IE_TARGET_SN(perr_elem);
 777        target_rcode = PERR_IE_TARGET_RCODE(perr_elem);
 778
 779        rcu_read_lock();
 780        mpath = mesh_path_lookup(sdata, target_addr);
 781        if (mpath) {
 782                struct sta_info *sta;
 783
 784                spin_lock_bh(&mpath->state_lock);
 785                sta = next_hop_deref_protected(mpath);
 786                if (mpath->flags & MESH_PATH_ACTIVE &&
 787                    ether_addr_equal(ta, sta->sta.addr) &&
 788                    !(mpath->flags & MESH_PATH_FIXED) &&
 789                    (!(mpath->flags & MESH_PATH_SN_VALID) ||
 790                    SN_GT(target_sn, mpath->sn)  || target_sn == 0)) {
 791                        mpath->flags &= ~MESH_PATH_ACTIVE;
 792                        if (target_sn != 0)
 793                                mpath->sn = target_sn;
 794                        else
 795                                mpath->sn += 1;
 796                        spin_unlock_bh(&mpath->state_lock);
 797                        if (!ifmsh->mshcfg.dot11MeshForwarding)
 798                                goto endperr;
 799                        mesh_path_error_tx(sdata, ttl, target_addr,
 800                                           target_sn, target_rcode,
 801                                           broadcast_addr);
 802                } else
 803                        spin_unlock_bh(&mpath->state_lock);
 804        }
 805endperr:
 806        rcu_read_unlock();
 807}
 808
 809static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 810                                    struct ieee80211_mgmt *mgmt,
 811                                    const struct ieee80211_rann_ie *rann)
 812{
 813        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 814        struct ieee80211_local *local = sdata->local;
 815        struct sta_info *sta;
 816        struct mesh_path *mpath;
 817        u8 ttl, flags, hopcount;
 818        const u8 *orig_addr;
 819        u32 orig_sn, new_metric, orig_metric, last_hop_metric, interval;
 820        bool root_is_gate;
 821
 822        ttl = rann->rann_ttl;
 823        flags = rann->rann_flags;
 824        root_is_gate = !!(flags & RANN_FLAG_IS_GATE);
 825        orig_addr = rann->rann_addr;
 826        orig_sn = le32_to_cpu(rann->rann_seq);
 827        interval = le32_to_cpu(rann->rann_interval);
 828        hopcount = rann->rann_hopcount;
 829        hopcount++;
 830        orig_metric = le32_to_cpu(rann->rann_metric);
 831
 832        /*  Ignore our own RANNs */
 833        if (ether_addr_equal(orig_addr, sdata->vif.addr))
 834                return;
 835
 836        mhwmp_dbg(sdata,
 837                  "received RANN from %pM via neighbour %pM (is_gate=%d)\n",
 838                  orig_addr, mgmt->sa, root_is_gate);
 839
 840        rcu_read_lock();
 841        sta = sta_info_get(sdata, mgmt->sa);
 842        if (!sta) {
 843                rcu_read_unlock();
 844                return;
 845        }
 846
 847        last_hop_metric = airtime_link_metric_get(local, sta);
 848        new_metric = orig_metric + last_hop_metric;
 849        if (new_metric < orig_metric)
 850                new_metric = MAX_METRIC;
 851
 852        mpath = mesh_path_lookup(sdata, orig_addr);
 853        if (!mpath) {
 854                mpath = mesh_path_add(sdata, orig_addr);
 855                if (IS_ERR(mpath)) {
 856                        rcu_read_unlock();
 857                        sdata->u.mesh.mshstats.dropped_frames_no_route++;
 858                        return;
 859                }
 860        }
 861
 862        if (!(SN_LT(mpath->sn, orig_sn)) &&
 863            !(mpath->sn == orig_sn && new_metric < mpath->rann_metric)) {
 864                rcu_read_unlock();
 865                return;
 866        }
 867
 868        if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
 869             (time_after(jiffies, mpath->last_preq_to_root +
 870                                  root_path_confirmation_jiffies(sdata)) ||
 871             time_before(jiffies, mpath->last_preq_to_root))) &&
 872             !(mpath->flags & MESH_PATH_FIXED) && (ttl != 0)) {
 873                mhwmp_dbg(sdata,
 874                          "time to refresh root mpath %pM\n",
 875                          orig_addr);
 876                mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
 877                mpath->last_preq_to_root = jiffies;
 878        }
 879
 880        mpath->sn = orig_sn;
 881        mpath->rann_metric = new_metric;
 882        mpath->is_root = true;
 883        /* Recording RANNs sender address to send individually
 884         * addressed PREQs destined for root mesh STA */
 885        memcpy(mpath->rann_snd_addr, mgmt->sa, ETH_ALEN);
 886
 887        if (root_is_gate)
 888                mesh_path_add_gate(mpath);
 889
 890        if (ttl <= 1) {
 891                ifmsh->mshstats.dropped_frames_ttl++;
 892                rcu_read_unlock();
 893                return;
 894        }
 895        ttl--;
 896
 897        if (ifmsh->mshcfg.dot11MeshForwarding) {
 898                mesh_path_sel_frame_tx(MPATH_RANN, flags, orig_addr,
 899                                       orig_sn, 0, NULL, 0, broadcast_addr,
 900                                       hopcount, ttl, interval,
 901                                       new_metric, 0, sdata);
 902        }
 903
 904        rcu_read_unlock();
 905}
 906
 907
 908void mesh_rx_path_sel_frame(struct ieee80211_sub_if_data *sdata,
 909                            struct ieee80211_mgmt *mgmt, size_t len)
 910{
 911        struct ieee802_11_elems elems;
 912        size_t baselen;
 913        u32 path_metric;
 914        struct sta_info *sta;
 915
 916        /* need action_code */
 917        if (len < IEEE80211_MIN_ACTION_SIZE + 1)
 918                return;
 919
 920        rcu_read_lock();
 921        sta = sta_info_get(sdata, mgmt->sa);
 922        if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
 923                rcu_read_unlock();
 924                return;
 925        }
 926        rcu_read_unlock();
 927
 928        baselen = (u8 *) mgmt->u.action.u.mesh_action.variable - (u8 *) mgmt;
 929        ieee802_11_parse_elems(mgmt->u.action.u.mesh_action.variable,
 930                               len - baselen, false, &elems, mgmt->bssid, NULL);
 931
 932        if (elems.preq) {
 933                if (elems.preq_len != 37)
 934                        /* Right now we support just 1 destination and no AE */
 935                        return;
 936                path_metric = hwmp_route_info_get(sdata, mgmt, elems.preq,
 937                                                  MPATH_PREQ);
 938                if (path_metric)
 939                        hwmp_preq_frame_process(sdata, mgmt, elems.preq,
 940                                                path_metric);
 941        }
 942        if (elems.prep) {
 943                if (elems.prep_len != 31)
 944                        /* Right now we support no AE */
 945                        return;
 946                path_metric = hwmp_route_info_get(sdata, mgmt, elems.prep,
 947                                                  MPATH_PREP);
 948                if (path_metric)
 949                        hwmp_prep_frame_process(sdata, mgmt, elems.prep,
 950                                                path_metric);
 951        }
 952        if (elems.perr) {
 953                if (elems.perr_len != 15)
 954                        /* Right now we support only one destination per PERR */
 955                        return;
 956                hwmp_perr_frame_process(sdata, mgmt, elems.perr);
 957        }
 958        if (elems.rann)
 959                hwmp_rann_frame_process(sdata, mgmt, elems.rann);
 960}
 961
 962/**
 963 * mesh_queue_preq - queue a PREQ to a given destination
 964 *
 965 * @mpath: mesh path to discover
 966 * @flags: special attributes of the PREQ to be sent
 967 *
 968 * Locking: the function must be called from within a rcu read lock block.
 969 *
 970 */
 971static void mesh_queue_preq(struct mesh_path *mpath, u8 flags)
 972{
 973        struct ieee80211_sub_if_data *sdata = mpath->sdata;
 974        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
 975        struct mesh_preq_queue *preq_node;
 976
 977        preq_node = kmalloc(sizeof(struct mesh_preq_queue), GFP_ATOMIC);
 978        if (!preq_node) {
 979                mhwmp_dbg(sdata, "could not allocate PREQ node\n");
 980                return;
 981        }
 982
 983        spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
 984        if (ifmsh->preq_queue_len == MAX_PREQ_QUEUE_LEN) {
 985                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 986                kfree(preq_node);
 987                if (printk_ratelimit())
 988                        mhwmp_dbg(sdata, "PREQ node queue full\n");
 989                return;
 990        }
 991
 992        spin_lock(&mpath->state_lock);
 993        if (mpath->flags & MESH_PATH_REQ_QUEUED) {
 994                spin_unlock(&mpath->state_lock);
 995                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
 996                kfree(preq_node);
 997                return;
 998        }
 999
1000        memcpy(preq_node->dst, mpath->dst, ETH_ALEN);
1001        preq_node->flags = flags;
1002
1003        mpath->flags |= MESH_PATH_REQ_QUEUED;
1004        spin_unlock(&mpath->state_lock);
1005
1006        list_add_tail(&preq_node->list, &ifmsh->preq_queue.list);
1007        ++ifmsh->preq_queue_len;
1008        spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1009
1010        if (time_after(jiffies, ifmsh->last_preq + min_preq_int_jiff(sdata)))
1011                ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1012
1013        else if (time_before(jiffies, ifmsh->last_preq)) {
1014                /* avoid long wait if did not send preqs for a long time
1015                 * and jiffies wrapped around
1016                 */
1017                ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
1018                ieee80211_queue_work(&sdata->local->hw, &sdata->work);
1019        } else
1020                mod_timer(&ifmsh->mesh_path_timer, ifmsh->last_preq +
1021                                                min_preq_int_jiff(sdata));
1022}
1023
1024/**
1025 * mesh_path_start_discovery - launch a path discovery from the PREQ queue
1026 *
1027 * @sdata: local mesh subif
1028 */
1029void mesh_path_start_discovery(struct ieee80211_sub_if_data *sdata)
1030{
1031        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1032        struct mesh_preq_queue *preq_node;
1033        struct mesh_path *mpath;
1034        u8 ttl, target_flags = 0;
1035        const u8 *da;
1036        u32 lifetime;
1037
1038        spin_lock_bh(&ifmsh->mesh_preq_queue_lock);
1039        if (!ifmsh->preq_queue_len ||
1040                time_before(jiffies, ifmsh->last_preq +
1041                                min_preq_int_jiff(sdata))) {
1042                spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1043                return;
1044        }
1045
1046        preq_node = list_first_entry(&ifmsh->preq_queue.list,
1047                        struct mesh_preq_queue, list);
1048        list_del(&preq_node->list);
1049        --ifmsh->preq_queue_len;
1050        spin_unlock_bh(&ifmsh->mesh_preq_queue_lock);
1051
1052        rcu_read_lock();
1053        mpath = mesh_path_lookup(sdata, preq_node->dst);
1054        if (!mpath)
1055                goto enddiscovery;
1056
1057        spin_lock_bh(&mpath->state_lock);
1058        if (mpath->flags & (MESH_PATH_DELETED | MESH_PATH_FIXED)) {
1059                spin_unlock_bh(&mpath->state_lock);
1060                goto enddiscovery;
1061        }
1062        mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1063        if (preq_node->flags & PREQ_Q_F_START) {
1064                if (mpath->flags & MESH_PATH_RESOLVING) {
1065                        spin_unlock_bh(&mpath->state_lock);
1066                        goto enddiscovery;
1067                } else {
1068                        mpath->flags &= ~MESH_PATH_RESOLVED;
1069                        mpath->flags |= MESH_PATH_RESOLVING;
1070                        mpath->discovery_retries = 0;
1071                        mpath->discovery_timeout = disc_timeout_jiff(sdata);
1072                }
1073        } else if (!(mpath->flags & MESH_PATH_RESOLVING) ||
1074                        mpath->flags & MESH_PATH_RESOLVED) {
1075                mpath->flags &= ~MESH_PATH_RESOLVING;
1076                spin_unlock_bh(&mpath->state_lock);
1077                goto enddiscovery;
1078        }
1079
1080        ifmsh->last_preq = jiffies;
1081
1082        if (time_after(jiffies, ifmsh->last_sn_update +
1083                                net_traversal_jiffies(sdata)) ||
1084            time_before(jiffies, ifmsh->last_sn_update)) {
1085                ++ifmsh->sn;
1086                sdata->u.mesh.last_sn_update = jiffies;
1087        }
1088        lifetime = default_lifetime(sdata);
1089        ttl = sdata->u.mesh.mshcfg.element_ttl;
1090        if (ttl == 0) {
1091                sdata->u.mesh.mshstats.dropped_frames_ttl++;
1092                spin_unlock_bh(&mpath->state_lock);
1093                goto enddiscovery;
1094        }
1095
1096        if (preq_node->flags & PREQ_Q_F_REFRESH)
1097                target_flags |= IEEE80211_PREQ_TO_FLAG;
1098        else
1099                target_flags &= ~IEEE80211_PREQ_TO_FLAG;
1100
1101        spin_unlock_bh(&mpath->state_lock);
1102        da = (mpath->is_root) ? mpath->rann_snd_addr : broadcast_addr;
1103        mesh_path_sel_frame_tx(MPATH_PREQ, 0, sdata->vif.addr, ifmsh->sn,
1104                               target_flags, mpath->dst, mpath->sn, da, 0,
1105                               ttl, lifetime, 0, ifmsh->preq_id++, sdata);
1106
1107        spin_lock_bh(&mpath->state_lock);
1108        if (!(mpath->flags & MESH_PATH_DELETED))
1109                mod_timer(&mpath->timer, jiffies + mpath->discovery_timeout);
1110        spin_unlock_bh(&mpath->state_lock);
1111
1112enddiscovery:
1113        rcu_read_unlock();
1114        kfree(preq_node);
1115}
1116
1117/**
1118 * mesh_nexthop_resolve - lookup next hop; conditionally start path discovery
1119 *
1120 * @skb: 802.11 frame to be sent
1121 * @sdata: network subif the frame will be sent through
1122 *
1123 * Lookup next hop for given skb and start path discovery if no
1124 * forwarding information is found.
1125 *
1126 * Returns: 0 if the next hop was found and -ENOENT if the frame was queued.
1127 * skb is freed here if no mpath could be allocated.
1128 */
1129int mesh_nexthop_resolve(struct ieee80211_sub_if_data *sdata,
1130                         struct sk_buff *skb)
1131{
1132        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1133        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
1134        struct mesh_path *mpath;
1135        struct sk_buff *skb_to_free = NULL;
1136        u8 *target_addr = hdr->addr3;
1137
1138        /* Nulls are only sent to peers for PS and should be pre-addressed */
1139        if (ieee80211_is_qos_nullfunc(hdr->frame_control))
1140                return 0;
1141
1142        /* Allow injected packets to bypass mesh routing */
1143        if (info->control.flags & IEEE80211_TX_CTRL_SKIP_MPATH_LOOKUP)
1144                return 0;
1145
1146        if (!mesh_nexthop_lookup(sdata, skb))
1147                return 0;
1148
1149        /* no nexthop found, start resolving */
1150        mpath = mesh_path_lookup(sdata, target_addr);
1151        if (!mpath) {
1152                mpath = mesh_path_add(sdata, target_addr);
1153                if (IS_ERR(mpath)) {
1154                        mesh_path_discard_frame(sdata, skb);
1155                        return PTR_ERR(mpath);
1156                }
1157        }
1158
1159        if (!(mpath->flags & MESH_PATH_RESOLVING) &&
1160            mesh_path_sel_is_hwmp(sdata))
1161                mesh_queue_preq(mpath, PREQ_Q_F_START);
1162
1163        if (skb_queue_len(&mpath->frame_queue) >= MESH_FRAME_QUEUE_LEN)
1164                skb_to_free = skb_dequeue(&mpath->frame_queue);
1165
1166        info->control.flags |= IEEE80211_TX_INTCFL_NEED_TXPROCESSING;
1167        ieee80211_set_qos_hdr(sdata, skb);
1168        skb_queue_tail(&mpath->frame_queue, skb);
1169        if (skb_to_free)
1170                mesh_path_discard_frame(sdata, skb_to_free);
1171
1172        return -ENOENT;
1173}
1174
1175/**
1176 * mesh_nexthop_lookup_nolearn - try to set next hop without path discovery
1177 * @skb: 802.11 frame to be sent
1178 * @sdata: network subif the frame will be sent through
1179 *
1180 * Check if the meshDA (addr3) of a unicast frame is a direct neighbor.
1181 * And if so, set the RA (addr1) to it to transmit to this node directly,
1182 * avoiding PREQ/PREP path discovery.
1183 *
1184 * Returns: 0 if the next hop was found and -ENOENT otherwise.
1185 */
1186static int mesh_nexthop_lookup_nolearn(struct ieee80211_sub_if_data *sdata,
1187                                       struct sk_buff *skb)
1188{
1189        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
1190        struct sta_info *sta;
1191
1192        if (is_multicast_ether_addr(hdr->addr1))
1193                return -ENOENT;
1194
1195        rcu_read_lock();
1196        sta = sta_info_get(sdata, hdr->addr3);
1197
1198        if (!sta || sta->mesh->plink_state != NL80211_PLINK_ESTAB) {
1199                rcu_read_unlock();
1200                return -ENOENT;
1201        }
1202        rcu_read_unlock();
1203
1204        memcpy(hdr->addr1, hdr->addr3, ETH_ALEN);
1205        memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1206        return 0;
1207}
1208
1209/**
1210 * mesh_nexthop_lookup - put the appropriate next hop on a mesh frame. Calling
1211 * this function is considered "using" the associated mpath, so preempt a path
1212 * refresh if this mpath expires soon.
1213 *
1214 * @skb: 802.11 frame to be sent
1215 * @sdata: network subif the frame will be sent through
1216 *
1217 * Returns: 0 if the next hop was found. Nonzero otherwise.
1218 */
1219int mesh_nexthop_lookup(struct ieee80211_sub_if_data *sdata,
1220                        struct sk_buff *skb)
1221{
1222        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1223        struct mesh_path *mpath;
1224        struct sta_info *next_hop;
1225        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
1226        u8 *target_addr = hdr->addr3;
1227
1228        if (ifmsh->mshcfg.dot11MeshNolearn &&
1229            !mesh_nexthop_lookup_nolearn(sdata, skb))
1230                return 0;
1231
1232        mpath = mesh_path_lookup(sdata, target_addr);
1233        if (!mpath || !(mpath->flags & MESH_PATH_ACTIVE))
1234                return -ENOENT;
1235
1236        if (time_after(jiffies,
1237                       mpath->exp_time -
1238                       msecs_to_jiffies(sdata->u.mesh.mshcfg.path_refresh_time)) &&
1239            ether_addr_equal(sdata->vif.addr, hdr->addr4) &&
1240            !(mpath->flags & MESH_PATH_RESOLVING) &&
1241            !(mpath->flags & MESH_PATH_FIXED))
1242                mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
1243
1244        next_hop = rcu_dereference(mpath->next_hop);
1245        if (next_hop) {
1246                memcpy(hdr->addr1, next_hop->sta.addr, ETH_ALEN);
1247                memcpy(hdr->addr2, sdata->vif.addr, ETH_ALEN);
1248                ieee80211_mps_set_frame_flags(sdata, next_hop, hdr);
1249                return 0;
1250        }
1251
1252        return -ENOENT;
1253}
1254
1255void mesh_path_timer(struct timer_list *t)
1256{
1257        struct mesh_path *mpath = from_timer(mpath, t, timer);
1258        struct ieee80211_sub_if_data *sdata = mpath->sdata;
1259        int ret;
1260
1261        if (sdata->local->quiescing)
1262                return;
1263
1264        spin_lock_bh(&mpath->state_lock);
1265        if (mpath->flags & MESH_PATH_RESOLVED ||
1266                        (!(mpath->flags & MESH_PATH_RESOLVING))) {
1267                mpath->flags &= ~(MESH_PATH_RESOLVING | MESH_PATH_RESOLVED);
1268                spin_unlock_bh(&mpath->state_lock);
1269        } else if (mpath->discovery_retries < max_preq_retries(sdata)) {
1270                ++mpath->discovery_retries;
1271                mpath->discovery_timeout *= 2;
1272                mpath->flags &= ~MESH_PATH_REQ_QUEUED;
1273                spin_unlock_bh(&mpath->state_lock);
1274                mesh_queue_preq(mpath, 0);
1275        } else {
1276                mpath->flags &= ~(MESH_PATH_RESOLVING |
1277                                  MESH_PATH_RESOLVED |
1278                                  MESH_PATH_REQ_QUEUED);
1279                mpath->exp_time = jiffies;
1280                spin_unlock_bh(&mpath->state_lock);
1281                if (!mpath->is_gate && mesh_gate_num(sdata) > 0) {
1282                        ret = mesh_path_send_to_gates(mpath);
1283                        if (ret)
1284                                mhwmp_dbg(sdata, "no gate was reachable\n");
1285                } else
1286                        mesh_path_flush_pending(mpath);
1287        }
1288}
1289
1290void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata)
1291{
1292        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
1293        u32 interval = ifmsh->mshcfg.dot11MeshHWMPRannInterval;
1294        u8 flags, target_flags = 0;
1295
1296        flags = (ifmsh->mshcfg.dot11MeshGateAnnouncementProtocol)
1297                        ? RANN_FLAG_IS_GATE : 0;
1298
1299        switch (ifmsh->mshcfg.dot11MeshHWMPRootMode) {
1300        case IEEE80211_PROACTIVE_RANN:
1301                mesh_path_sel_frame_tx(MPATH_RANN, flags, sdata->vif.addr,
1302                                       ++ifmsh->sn, 0, NULL, 0, broadcast_addr,
1303                                       0, ifmsh->mshcfg.element_ttl,
1304                                       interval, 0, 0, sdata);
1305                break;
1306        case IEEE80211_PROACTIVE_PREQ_WITH_PREP:
1307                flags |= IEEE80211_PREQ_PROACTIVE_PREP_FLAG;
1308                fallthrough;
1309        case IEEE80211_PROACTIVE_PREQ_NO_PREP:
1310                interval = ifmsh->mshcfg.dot11MeshHWMPactivePathToRootTimeout;
1311                target_flags |= IEEE80211_PREQ_TO_FLAG |
1312                                IEEE80211_PREQ_USN_FLAG;
1313                mesh_path_sel_frame_tx(MPATH_PREQ, flags, sdata->vif.addr,
1314                                       ++ifmsh->sn, target_flags,
1315                                       (u8 *) broadcast_addr, 0, broadcast_addr,
1316                                       0, ifmsh->mshcfg.element_ttl, interval,
1317                                       0, ifmsh->preq_id++, sdata);
1318                break;
1319        default:
1320                mhwmp_dbg(sdata, "Proactive mechanism not supported\n");
1321                return;
1322        }
1323}
1324