net/batman-adv/bat_v_elp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2011-2020  B.A.T.M.A.N. contributors:
   3  *
   4  * Linus Lüssing, Marek Lindner
   5  */
   6
   7 #include "bat_v_elp.h"
   8 #include "main.h"
   9
  10 #include <linux/atomic.h>
  11 #include <linux/bitops.h>
  12 #include <linux/byteorder/generic.h>
  13 #include <linux/errno.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/ethtool.h>
  16 #include <linux/gfp.h>
  17 #include <linux/if_ether.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/kernel.h>
  20 #include <linux/kref.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/nl80211.h>
  23 #include <linux/prandom.h>
  24 #include <linux/random.h>
  25 #include <linux/rculist.h>
  26 #include <linux/rcupdate.h>
  27 #include <linux/rtnetlink.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/stddef.h>
  30 #include <linux/string.h>
  31 #include <linux/types.h>
  32 #include <linux/workqueue.h>
  33 #include <net/cfg80211.h>
  34 #include <uapi/linux/batadv_packet.h>
  35
  36 #include "bat_algo.h"
  37 #include "bat_v_ogm.h"
  38 #include "hard-interface.h"
  39 #include "log.h"
  40 #include "originator.h"
  41 #include "routing.h"
  42 #include "send.h"
  43
  44 /**
  45  * batadv_v_elp_start_timer() - restart timer for ELP periodic work
  46  * @hard_iface: the interface for which the timer has to be reset
  47  */
  48 static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
  49 {
  50         unsigned int msecs;
  51
  52         msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
  53         msecs += prandom_u32_max(2 * BATADV_JITTER);
  54
  55         queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
  56                            msecs_to_jiffies(msecs));
  57 }
  58
  59 /**
  60  * batadv_v_elp_get_throughput() - get the throughput towards a neighbour
  61  * @neigh: the neighbour for which the throughput has to be obtained
  62  *
  63  * Return: The throughput towards the given neighbour in multiples of 100kpbs
  64  *         (a value of '1' equals 0.1Mbps, '10' equals 1Mbps, etc).
  65  */
  66 static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
  67 {
  68         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
  69         struct ethtool_link_ksettings link_settings;
  70         struct net_device *real_netdev;
  71         struct station_info sinfo;
  72         u32 throughput;
  73         int ret;
  74
  75         /* if the user specified a customised value for this interface, then
  76          * return it directly
  77          */
  78         throughput =  atomic_read(&hard_iface->bat_v.throughput_override);
  79         if (throughput != 0)
  80                 return throughput;
  81
  82         /* if this is a wireless device, then ask its throughput through
  83          * cfg80211 API
  84          */
  85         if (batadv_is_wifi_hardif(hard_iface)) {
  86                 if (!batadv_is_cfg80211_hardif(hard_iface))
  87                         /* unsupported WiFi driver version */
  88                         goto default_throughput;
  89
  90                 real_netdev = batadv_get_real_netdev(hard_iface->net_dev);
  91                 if (!real_netdev)
  92                         goto default_throughput;
  93
  94                 ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo);
  95
  96                 if (!ret) {
  97                         /* free the TID stats immediately */
  98                         cfg80211_sinfo_release_content(&sinfo);
  99                 }
 100
 101                 dev_put(real_netdev);
 102                 if (ret == -ENOENT) {
 103                         /* Node is not associated anymore! It would be
 104                          * possible to delete this neighbor. For now set
 105                          * the throughput metric to 0.
 106                          */
 107                         return 0;
 108                 }
 109                 if (ret)
 110                         goto default_throughput;
 111
 112                 if (sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT))
 113                         return sinfo.expected_throughput / 100;
 114
 115                 /* try to estimate the expected throughput based on reported tx
 116                  * rates
 117                  */
 118                 if (sinfo.filled & BIT(NL80211_STA_INFO_TX_BITRATE))
 119                         return cfg80211_calculate_bitrate(&sinfo.txrate) / 3;
 120
 121                 goto default_throughput;
 122         }
 123
 124         /* if not a wifi interface, check if this device provides data via
 125          * ethtool (e.g. an Ethernet adapter)
 126          */
 127         memset(&link_settings, 0, sizeof(link_settings));
 128         rtnl_lock();
 129         ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
 130         rtnl_unlock();
 131         if (ret == 0) {
 132                 /* link characteristics might change over time */
 133                 if (link_settings.base.duplex == DUPLEX_FULL)
 134                         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 135                 else
 136                         hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 137
 138                 throughput = link_settings.base.speed;
 139                 if (throughput && throughput != SPEED_UNKNOWN)
 140                         return throughput * 10;
 141         }
 142
 143 default_throughput:
 144         if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
 145                 batadv_info(hard_iface->soft_iface,
 146                             "WiFi driver or ethtool info does not provide information about link speeds on interface %s, therefore defaulting to hardcoded throughput values of %u.%1u Mbps. Consider overriding the throughput manually or checking your driver.\n",
 147                             hard_iface->net_dev->name,
 148                             BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
 149                             BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
 150                 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
 151         }
 152
 153         /* if none of the above cases apply, return the base_throughput */
 154         return BATADV_THROUGHPUT_DEFAULT_VALUE;
 155 }
 156
 157 /**
 158  * batadv_v_elp_throughput_metric_update() - worker updating the throughput
 159  *  metric of a single hop neighbour
 160  * @work: the work queue item
 161  */
 162 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
 163 {
 164         struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
 165         struct batadv_hardif_neigh_node *neigh;
 166
 167         neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
 168                                    metric_work);
 169         neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
 170                              bat_v);
 171
 172         ewma_throughput_add(&neigh->bat_v.throughput,
 173                             batadv_v_elp_get_throughput(neigh));
 174
 175         /* decrement refcounter to balance increment performed before scheduling
 176          * this task
 177          */
 178         batadv_hardif_neigh_put(neigh);
 179 }
 180
 181 /**
 182  * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
 183  * @neigh: the neighbour to probe
 184  *
 185  * Sends a predefined number of unicast wifi packets to a given neighbour in
 186  * order to trigger the throughput estimation on this link by the RC algorithm.
 187  * Packets are sent only if there is not enough payload unicast traffic towards
 188  * this neighbour..
 189  *
 190  * Return: True on success and false in case of error during skb preparation.
 191  */
 192 static bool
 193 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
 194 {
 195         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 196         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 197         unsigned long last_tx_diff;
 198         struct sk_buff *skb;
 199         int probe_len, i;
 200         int elp_skb_len;
 201
 202         /* this probing routine is for Wifi neighbours only */
 203         if (!batadv_is_wifi_hardif(hard_iface))
 204                 return true;
 205
 206         /* probe the neighbor only if no unicast packets have been sent
 207          * to it in the last 100 milliseconds: this is the rate control
 208          * algorithm sampling interval (minstrel). In this way, if not
 209          * enough traffic has been sent to the neighbor, batman-adv can
 210          * generate 2 probe packets and push the RC algorithm to perform
 211          * the sampling
 212          */
 213         last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
 214         if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
 215                 return true;
 216
 217         probe_len = max_t(int, sizeof(struct batadv_elp_packet),
 218                           BATADV_ELP_MIN_PROBE_SIZE);
 219
 220         for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
 221                 elp_skb_len = hard_iface->bat_v.elp_skb->len;
 222                 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
 223                                       probe_len - elp_skb_len,
 224                                       GFP_ATOMIC);
 225                 if (!skb)
 226                         return false;
 227
 228                 /* Tell the skb to get as big as the allocated space (we want
 229                  * the packet to be exactly of that size to make the link
 230                  * throughput estimation effective.
 231                  */
 232                 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);
 233
 234                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 235                            "Sending unicast (probe) ELP packet on interface %s to %pM\n",
 236                            hard_iface->net_dev->name, neigh->addr);
 237
 238                 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
 239         }
 240
 241         return true;
 242 }
 243
 244 /**
 245  * batadv_v_elp_periodic_work() - ELP periodic task per interface
 246  * @work: work queue item
 247  *
 248  * Emits broadcast ELP messages in regular intervals.
 249  */
 250 static void batadv_v_elp_periodic_work(struct work_struct *work)
 251 {
 252         struct batadv_hardif_neigh_node *hardif_neigh;
 253         struct batadv_hard_iface *hard_iface;
 254         struct batadv_hard_iface_bat_v *bat_v;
 255         struct batadv_elp_packet *elp_packet;
 256         struct batadv_priv *bat_priv;
 257         struct sk_buff *skb;
 258         u32 elp_interval;
 259         bool ret;
 260
 261         bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
 262         hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 263         bat_priv = netdev_priv(hard_iface->soft_iface);
 264
 265         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 266                 goto out;
 267
 268         /* we are in the process of shutting this interface down */
 269         if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
 270             hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
 271                 goto out;
 272
 273         /* the interface was enabled but may not be ready yet */
 274         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 275                 goto restart_timer;
 276
 277         skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
 278         if (!skb)
 279                 goto restart_timer;
 280
 281         elp_packet = (struct batadv_elp_packet *)skb->data;
 282         elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
 283         elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
 284         elp_packet->elp_interval = htonl(elp_interval);
 285
 286         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 287                    "Sending broadcast ELP packet on interface %s, seqno %u\n",
 288                    hard_iface->net_dev->name,
 289                    atomic_read(&hard_iface->bat_v.elp_seqno));
 290
 291         batadv_send_broadcast_skb(skb, hard_iface);
 292
 293         atomic_inc(&hard_iface->bat_v.elp_seqno);
 294
 295         /* The throughput metric is updated on each sent packet. This way, if a
 296          * node is dead and no longer sends packets, batman-adv is still able to
 297          * react timely to its death.
 298          *
 299          * The throughput metric is updated by following these steps:
 300          * 1) if the hard_iface is wifi => send a number of unicast ELPs for
 301          *    probing/sampling to each neighbor
 302          * 2) update the throughput metric value of each neighbor (note that the
 303          *    value retrieved in this step might be 100ms old because the
 304          *    probing packets at point 1) could still be in the HW queue)
 305          */
 306         rcu_read_lock();
 307         hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
 308                 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
 309                         /* if something goes wrong while probing, better to stop
 310                          * sending packets immediately and reschedule the task
 311                          */
 312                         break;
 313
 314                 if (!kref_get_unless_zero(&hardif_neigh->refcount))
 315                         continue;
 316
 317                 /* Reading the estimated throughput from cfg80211 is a task that
 318                  * may sleep and that is not allowed in an rcu protected
 319                  * context. Therefore schedule a task for that.
 320                  */
 321                 ret = queue_work(batadv_event_workqueue,
 322                                  &hardif_neigh->bat_v.metric_work);
 323
 324                 if (!ret)
 325                         batadv_hardif_neigh_put(hardif_neigh);
 326         }
 327         rcu_read_unlock();
 328
 329 restart_timer:
 330         batadv_v_elp_start_timer(hard_iface);
 331 out:
 332         return;
 333 }
 334
 335 /**
 336  * batadv_v_elp_iface_enable() - setup the ELP interface private resources
 337  * @hard_iface: interface for which the data has to be prepared
 338  *
 339  * Return: 0 on success or a -ENOMEM in case of failure.
 340  */
 341 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 342 {
 343         static const size_t tvlv_padding = sizeof(__be32);
 344         struct batadv_elp_packet *elp_packet;
 345         unsigned char *elp_buff;
 346         u32 random_seqno;
 347         size_t size;
 348         int res = -ENOMEM;
 349
 350         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
 351         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 352         if (!hard_iface->bat_v.elp_skb)
 353                 goto out;
 354
 355         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 356         elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
 357                                 BATADV_ELP_HLEN + tvlv_padding);
 358         elp_packet = (struct batadv_elp_packet *)elp_buff;
 359
 360         elp_packet->packet_type = BATADV_ELP;
 361         elp_packet->version = BATADV_COMPAT_VERSION;
 362
 363         /* randomize initial seqno to avoid collision */
 364         get_random_bytes(&random_seqno, sizeof(random_seqno));
 365         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 366
 367         /* assume full-duplex by default */
 368         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 369
 370         /* warn the user (again) if there is no throughput data is available */
 371         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 372
 373         if (batadv_is_wifi_hardif(hard_iface))
 374                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 375
 376         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 377                           batadv_v_elp_periodic_work);
 378         batadv_v_elp_start_timer(hard_iface);
 379         res = 0;
 380
 381 out:
 382         return res;
 383 }
 384
 385 /**
 386  * batadv_v_elp_iface_disable() - release ELP interface private resources
 387  * @hard_iface: interface for which the resources have to be released
 388  */
 389 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 390 {
 391         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 392
 393         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 394         hard_iface->bat_v.elp_skb = NULL;
 395 }
 396
 397 /**
 398  * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
 399  *  hard-interface
 400  * @primary_iface: the new primary interface
 401  * @hard_iface: interface holding the to-be-updated buffer
 402  */
 403 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 404                                  struct batadv_hard_iface *hard_iface)
 405 {
 406         struct batadv_elp_packet *elp_packet;
 407         struct sk_buff *skb;
 408
 409         if (!hard_iface->bat_v.elp_skb)
 410                 return;
 411
 412         skb = hard_iface->bat_v.elp_skb;
 413         elp_packet = (struct batadv_elp_packet *)skb->data;
 414         ether_addr_copy(elp_packet->orig,
 415                         primary_iface->net_dev->dev_addr);
 416 }
 417
 418 /**
 419  * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
 420  *  primary interface
 421  * @primary_iface: the new primary interface
 422  */
 423 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 424 {
 425         struct batadv_hard_iface *hard_iface;
 426
 427         /* update orig field of every elp iface belonging to this mesh */
 428         rcu_read_lock();
 429         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 430                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 431                         continue;
 432
 433                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 434         }
 435         rcu_read_unlock();
 436 }
 437
 438 /**
 439  * batadv_v_elp_neigh_update() - update an ELP neighbour node
 440  * @bat_priv: the bat priv with all the soft interface information
 441  * @neigh_addr: the neighbour interface address
 442  * @if_incoming: the interface the packet was received through
 443  * @elp_packet: the received ELP packet
 444  *
 445  * Updates the ELP neighbour node state with the data received within the new
 446  * ELP packet.
 447  */
 448 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 449                                       u8 *neigh_addr,
 450                                       struct batadv_hard_iface *if_incoming,
 451                                       struct batadv_elp_packet *elp_packet)
 452
 453 {
 454         struct batadv_neigh_node *neigh;
 455         struct batadv_orig_node *orig_neigh;
 456         struct batadv_hardif_neigh_node *hardif_neigh;
 457         s32 seqno_diff;
 458         s32 elp_latest_seqno;
 459
 460         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 461         if (!orig_neigh)
 462                 return;
 463
 464         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 465                                                 if_incoming, neigh_addr);
 466         if (!neigh)
 467                 goto orig_free;
 468
 469         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 470         if (!hardif_neigh)
 471                 goto neigh_free;
 472
 473         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 474         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 475
 476         /* known or older sequence numbers are ignored. However always adopt
 477          * if the router seems to have been restarted.
 478          */
 479         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 480                 goto hardif_free;
 481
 482         neigh->last_seen = jiffies;
 483         hardif_neigh->last_seen = jiffies;
 484         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 485         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 486
 487 hardif_free:
 488         if (hardif_neigh)
 489                 batadv_hardif_neigh_put(hardif_neigh);
 490 neigh_free:
 491         if (neigh)
 492                 batadv_neigh_node_put(neigh);
 493 orig_free:
 494         if (orig_neigh)
 495                 batadv_orig_node_put(orig_neigh);
 496 }
 497
 498 /**
 499  * batadv_v_elp_packet_recv() - main ELP packet handler
 500  * @skb: the received packet
 501  * @if_incoming: the interface this packet was received through
 502  *
 503  * Return: NET_RX_SUCCESS and consumes the skb if the packet was properly
 504  * processed or NET_RX_DROP in case of failure.
 505  */
 506 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 507                              struct batadv_hard_iface *if_incoming)
 508 {
 509         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 510         struct batadv_elp_packet *elp_packet;
 511         struct batadv_hard_iface *primary_if;
 512         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 513         bool res;
 514         int ret = NET_RX_DROP;
 515
 516         res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 517         if (!res)
 518                 goto free_skb;
 519
 520         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 521                 goto free_skb;
 522
 523         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 524          * that does not have B.A.T.M.A.N. V ELP enabled ?
 525          */
 526         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 527                 goto free_skb;
 528
 529         elp_packet = (struct batadv_elp_packet *)skb->data;
 530
 531         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 532                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 533                    ethhdr->h_source, ntohl(elp_packet->seqno),
 534                    elp_packet->orig);
 535
 536         primary_if = batadv_primary_if_get_selected(bat_priv);
 537         if (!primary_if)
 538                 goto free_skb;
 539
 540         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 541                                   elp_packet);
 542
 543         ret = NET_RX_SUCCESS;
 544         batadv_hardif_put(primary_if);
 545
 546 free_skb:
 547         if (ret == NET_RX_SUCCESS)
 548                 consume_skb(skb);
 549         else
 550                 kfree_skb(skb);
 551
 552         return ret;
 553 }