net/batman-adv/bat_v_elp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 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/container_of.h>
  14 #include <linux/errno.h>
  15 #include <linux/etherdevice.h>
  16 #include <linux/ethtool.h>
  17 #include <linux/gfp.h>
  18 #include <linux/if_ether.h>
  19 #include <linux/jiffies.h>
  20 #include <linux/kref.h>
  21 #include <linux/minmax.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/nl80211.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 += get_random_u32_below(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         rtnl_lock();
 128         ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
 129         rtnl_unlock();
 130         if (ret == 0) {
 131                 /* link characteristics might change over time */
 132                 if (link_settings.base.duplex == DUPLEX_FULL)
 133                         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 134                 else
 135                         hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 136
 137                 throughput = link_settings.base.speed;
 138                 if (throughput && throughput != SPEED_UNKNOWN)
 139                         return throughput * 10;
 140         }
 141
 142 default_throughput:
 143         if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
 144                 batadv_info(hard_iface->soft_iface,
 145                             "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",
 146                             hard_iface->net_dev->name,
 147                             BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
 148                             BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
 149                 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
 150         }
 151
 152         /* if none of the above cases apply, return the base_throughput */
 153         return BATADV_THROUGHPUT_DEFAULT_VALUE;
 154 }
 155
 156 /**
 157  * batadv_v_elp_throughput_metric_update() - worker updating the throughput
 158  *  metric of a single hop neighbour
 159  * @work: the work queue item
 160  */
 161 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
 162 {
 163         struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
 164         struct batadv_hardif_neigh_node *neigh;
 165
 166         neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
 167                                    metric_work);
 168         neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
 169                              bat_v);
 170
 171         ewma_throughput_add(&neigh->bat_v.throughput,
 172                             batadv_v_elp_get_throughput(neigh));
 173
 174         /* decrement refcounter to balance increment performed before scheduling
 175          * this task
 176          */
 177         batadv_hardif_neigh_put(neigh);
 178 }
 179
 180 /**
 181  * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
 182  * @neigh: the neighbour to probe
 183  *
 184  * Sends a predefined number of unicast wifi packets to a given neighbour in
 185  * order to trigger the throughput estimation on this link by the RC algorithm.
 186  * Packets are sent only if there is not enough payload unicast traffic towards
 187  * this neighbour..
 188  *
 189  * Return: True on success and false in case of error during skb preparation.
 190  */
 191 static bool
 192 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
 193 {
 194         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 195         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 196         unsigned long last_tx_diff;
 197         struct sk_buff *skb;
 198         int probe_len, i;
 199         int elp_skb_len;
 200
 201         /* this probing routine is for Wifi neighbours only */
 202         if (!batadv_is_wifi_hardif(hard_iface))
 203                 return true;
 204
 205         /* probe the neighbor only if no unicast packets have been sent
 206          * to it in the last 100 milliseconds: this is the rate control
 207          * algorithm sampling interval (minstrel). In this way, if not
 208          * enough traffic has been sent to the neighbor, batman-adv can
 209          * generate 2 probe packets and push the RC algorithm to perform
 210          * the sampling
 211          */
 212         last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
 213         if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
 214                 return true;
 215
 216         probe_len = max_t(int, sizeof(struct batadv_elp_packet),
 217                           BATADV_ELP_MIN_PROBE_SIZE);
 218
 219         for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
 220                 elp_skb_len = hard_iface->bat_v.elp_skb->len;
 221                 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
 222                                       probe_len - elp_skb_len,
 223                                       GFP_ATOMIC);
 224                 if (!skb)
 225                         return false;
 226
 227                 /* Tell the skb to get as big as the allocated space (we want
 228                  * the packet to be exactly of that size to make the link
 229                  * throughput estimation effective.
 230                  */
 231                 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);
 232
 233                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 234                            "Sending unicast (probe) ELP packet on interface %s to %pM\n",
 235                            hard_iface->net_dev->name, neigh->addr);
 236
 237                 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
 238         }
 239
 240         return true;
 241 }
 242
 243 /**
 244  * batadv_v_elp_periodic_work() - ELP periodic task per interface
 245  * @work: work queue item
 246  *
 247  * Emits broadcast ELP messages in regular intervals.
 248  */
 249 static void batadv_v_elp_periodic_work(struct work_struct *work)
 250 {
 251         struct batadv_hardif_neigh_node *hardif_neigh;
 252         struct batadv_hard_iface *hard_iface;
 253         struct batadv_hard_iface_bat_v *bat_v;
 254         struct batadv_elp_packet *elp_packet;
 255         struct batadv_priv *bat_priv;
 256         struct sk_buff *skb;
 257         u32 elp_interval;
 258         bool ret;
 259
 260         bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
 261         hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 262         bat_priv = netdev_priv(hard_iface->soft_iface);
 263
 264         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 265                 goto out;
 266
 267         /* we are in the process of shutting this interface down */
 268         if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
 269             hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
 270                 goto out;
 271
 272         /* the interface was enabled but may not be ready yet */
 273         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 274                 goto restart_timer;
 275
 276         skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
 277         if (!skb)
 278                 goto restart_timer;
 279
 280         elp_packet = (struct batadv_elp_packet *)skb->data;
 281         elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
 282         elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
 283         elp_packet->elp_interval = htonl(elp_interval);
 284
 285         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 286                    "Sending broadcast ELP packet on interface %s, seqno %u\n",
 287                    hard_iface->net_dev->name,
 288                    atomic_read(&hard_iface->bat_v.elp_seqno));
 289
 290         batadv_send_broadcast_skb(skb, hard_iface);
 291
 292         atomic_inc(&hard_iface->bat_v.elp_seqno);
 293
 294         /* The throughput metric is updated on each sent packet. This way, if a
 295          * node is dead and no longer sends packets, batman-adv is still able to
 296          * react timely to its death.
 297          *
 298          * The throughput metric is updated by following these steps:
 299          * 1) if the hard_iface is wifi => send a number of unicast ELPs for
 300          *    probing/sampling to each neighbor
 301          * 2) update the throughput metric value of each neighbor (note that the
 302          *    value retrieved in this step might be 100ms old because the
 303          *    probing packets at point 1) could still be in the HW queue)
 304          */
 305         rcu_read_lock();
 306         hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
 307                 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
 308                         /* if something goes wrong while probing, better to stop
 309                          * sending packets immediately and reschedule the task
 310                          */
 311                         break;
 312
 313                 if (!kref_get_unless_zero(&hardif_neigh->refcount))
 314                         continue;
 315
 316                 /* Reading the estimated throughput from cfg80211 is a task that
 317                  * may sleep and that is not allowed in an rcu protected
 318                  * context. Therefore schedule a task for that.
 319                  */
 320                 ret = queue_work(batadv_event_workqueue,
 321                                  &hardif_neigh->bat_v.metric_work);
 322
 323                 if (!ret)
 324                         batadv_hardif_neigh_put(hardif_neigh);
 325         }
 326         rcu_read_unlock();
 327
 328 restart_timer:
 329         batadv_v_elp_start_timer(hard_iface);
 330 out:
 331         return;
 332 }
 333
 334 /**
 335  * batadv_v_elp_iface_enable() - setup the ELP interface private resources
 336  * @hard_iface: interface for which the data has to be prepared
 337  *
 338  * Return: 0 on success or a -ENOMEM in case of failure.
 339  */
 340 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 341 {
 342         static const size_t tvlv_padding = sizeof(__be32);
 343         struct batadv_elp_packet *elp_packet;
 344         unsigned char *elp_buff;
 345         u32 random_seqno;
 346         size_t size;
 347         int res = -ENOMEM;
 348
 349         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
 350         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 351         if (!hard_iface->bat_v.elp_skb)
 352                 goto out;
 353
 354         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 355         elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
 356                                 BATADV_ELP_HLEN + tvlv_padding);
 357         elp_packet = (struct batadv_elp_packet *)elp_buff;
 358
 359         elp_packet->packet_type = BATADV_ELP;
 360         elp_packet->version = BATADV_COMPAT_VERSION;
 361
 362         /* randomize initial seqno to avoid collision */
 363         get_random_bytes(&random_seqno, sizeof(random_seqno));
 364         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 365
 366         /* assume full-duplex by default */
 367         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 368
 369         /* warn the user (again) if there is no throughput data is available */
 370         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 371
 372         if (batadv_is_wifi_hardif(hard_iface))
 373                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 374
 375         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 376                           batadv_v_elp_periodic_work);
 377         batadv_v_elp_start_timer(hard_iface);
 378         res = 0;
 379
 380 out:
 381         return res;
 382 }
 383
 384 /**
 385  * batadv_v_elp_iface_disable() - release ELP interface private resources
 386  * @hard_iface: interface for which the resources have to be released
 387  */
 388 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 389 {
 390         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 391
 392         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 393         hard_iface->bat_v.elp_skb = NULL;
 394 }
 395
 396 /**
 397  * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
 398  *  hard-interface
 399  * @primary_iface: the new primary interface
 400  * @hard_iface: interface holding the to-be-updated buffer
 401  */
 402 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 403                                  struct batadv_hard_iface *hard_iface)
 404 {
 405         struct batadv_elp_packet *elp_packet;
 406         struct sk_buff *skb;
 407
 408         if (!hard_iface->bat_v.elp_skb)
 409                 return;
 410
 411         skb = hard_iface->bat_v.elp_skb;
 412         elp_packet = (struct batadv_elp_packet *)skb->data;
 413         ether_addr_copy(elp_packet->orig,
 414                         primary_iface->net_dev->dev_addr);
 415 }
 416
 417 /**
 418  * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
 419  *  primary interface
 420  * @primary_iface: the new primary interface
 421  */
 422 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 423 {
 424         struct batadv_hard_iface *hard_iface;
 425
 426         /* update orig field of every elp iface belonging to this mesh */
 427         rcu_read_lock();
 428         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 429                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 430                         continue;
 431
 432                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 433         }
 434         rcu_read_unlock();
 435 }
 436
 437 /**
 438  * batadv_v_elp_neigh_update() - update an ELP neighbour node
 439  * @bat_priv: the bat priv with all the soft interface information
 440  * @neigh_addr: the neighbour interface address
 441  * @if_incoming: the interface the packet was received through
 442  * @elp_packet: the received ELP packet
 443  *
 444  * Updates the ELP neighbour node state with the data received within the new
 445  * ELP packet.
 446  */
 447 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 448                                       u8 *neigh_addr,
 449                                       struct batadv_hard_iface *if_incoming,
 450                                       struct batadv_elp_packet *elp_packet)
 451
 452 {
 453         struct batadv_neigh_node *neigh;
 454         struct batadv_orig_node *orig_neigh;
 455         struct batadv_hardif_neigh_node *hardif_neigh;
 456         s32 seqno_diff;
 457         s32 elp_latest_seqno;
 458
 459         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 460         if (!orig_neigh)
 461                 return;
 462
 463         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 464                                                 if_incoming, neigh_addr);
 465         if (!neigh)
 466                 goto orig_free;
 467
 468         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 469         if (!hardif_neigh)
 470                 goto neigh_free;
 471
 472         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 473         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 474
 475         /* known or older sequence numbers are ignored. However always adopt
 476          * if the router seems to have been restarted.
 477          */
 478         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 479                 goto hardif_free;
 480
 481         neigh->last_seen = jiffies;
 482         hardif_neigh->last_seen = jiffies;
 483         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 484         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 485
 486 hardif_free:
 487         batadv_hardif_neigh_put(hardif_neigh);
 488 neigh_free:
 489         batadv_neigh_node_put(neigh);
 490 orig_free:
 491         batadv_orig_node_put(orig_neigh);
 492 }
 493
 494 /**
 495  * batadv_v_elp_packet_recv() - main ELP packet handler
 496  * @skb: the received packet
 497  * @if_incoming: the interface this packet was received through
 498  *
 499  * Return: NET_RX_SUCCESS and consumes the skb if the packet was properly
 500  * processed or NET_RX_DROP in case of failure.
 501  */
 502 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 503                              struct batadv_hard_iface *if_incoming)
 504 {
 505         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 506         struct batadv_elp_packet *elp_packet;
 507         struct batadv_hard_iface *primary_if;
 508         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 509         bool res;
 510         int ret = NET_RX_DROP;
 511
 512         res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 513         if (!res)
 514                 goto free_skb;
 515
 516         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 517                 goto free_skb;
 518
 519         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 520          * that does not have B.A.T.M.A.N. V ELP enabled ?
 521          */
 522         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 523                 goto free_skb;
 524
 525         elp_packet = (struct batadv_elp_packet *)skb->data;
 526
 527         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 528                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 529                    ethhdr->h_source, ntohl(elp_packet->seqno),
 530                    elp_packet->orig);
 531
 532         primary_if = batadv_primary_if_get_selected(bat_priv);
 533         if (!primary_if)
 534                 goto free_skb;
 535
 536         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 537                                   elp_packet);
 538
 539         ret = NET_RX_SUCCESS;
 540         batadv_hardif_put(primary_if);
 541
 542 free_skb:
 543         if (ret == NET_RX_SUCCESS)
 544                 consume_skb(skb);
 545         else
 546                 kfree_skb(skb);
 547
 548         return ret;
 549 }