net/batman-adv/bat_v_elp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2011-2019  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/random.h>
  24 #include <linux/rculist.h>
  25 #include <linux/rcupdate.h>
  26 #include <linux/rtnetlink.h>
  27 #include <linux/skbuff.h>
  28 #include <linux/stddef.h>
  29 #include <linux/string.h>
  30 #include <linux/types.h>
  31 #include <linux/workqueue.h>
  32 #include <net/cfg80211.h>
  33 #include <uapi/linux/batadv_packet.h>
  34
  35 #include "bat_algo.h"
  36 #include "bat_v_ogm.h"
  37 #include "hard-interface.h"
  38 #include "log.h"
  39 #include "originator.h"
  40 #include "routing.h"
  41 #include "send.h"
  42
  43 /**
  44  * batadv_v_elp_start_timer() - restart timer for ELP periodic work
  45  * @hard_iface: the interface for which the timer has to be reset
  46  */
  47 static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
  48 {
  49         unsigned int msecs;
  50
  51         msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
  52         msecs += prandom_u32() % (2 * BATADV_JITTER);
  53
  54         queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
  55                            msecs_to_jiffies(msecs));
  56 }
  57
  58 /**
  59  * batadv_v_elp_get_throughput() - get the throughput towards a neighbour
  60  * @neigh: the neighbour for which the throughput has to be obtained
  61  *
  62  * Return: The throughput towards the given neighbour in multiples of 100kpbs
  63  *         (a value of '1' equals to 0.1Mbps, '10' equals 1Mbps, etc).
  64  */
  65 static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
  66 {
  67         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
  68         struct ethtool_link_ksettings link_settings;
  69         struct net_device *real_netdev;
  70         struct station_info sinfo;
  71         u32 throughput;
  72         int ret;
  73
  74         /* if the user specified a customised value for this interface, then
  75          * return it directly
  76          */
  77         throughput =  atomic_read(&hard_iface->bat_v.throughput_override);
  78         if (throughput != 0)
  79                 return throughput;
  80
  81         /* if this is a wireless device, then ask its throughput through
  82          * cfg80211 API
  83          */
  84         if (batadv_is_wifi_hardif(hard_iface)) {
  85                 if (!batadv_is_cfg80211_hardif(hard_iface))
  86                         /* unsupported WiFi driver version */
  87                         goto default_throughput;
  88
  89                 real_netdev = batadv_get_real_netdev(hard_iface->net_dev);
  90                 if (!real_netdev)
  91                         goto default_throughput;
  92
  93                 ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo);
  94
  95                 if (!ret) {
  96                         /* free the TID stats immediately */
  97                         cfg80211_sinfo_release_content(&sinfo);
  98                 }
  99
 100                 dev_put(real_netdev);
 101                 if (ret == -ENOENT) {
 102                         /* Node is not associated anymore! It would be
 103                          * possible to delete this neighbor. For now set
 104                          * the throughput metric to 0.
 105                          */
 106                         return 0;
 107                 }
 108                 if (ret)
 109                         goto default_throughput;
 110                 if (!(sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)))
 111                         goto default_throughput;
 112
 113                 return sinfo.expected_throughput / 100;
 114         }
 115
 116         /* if not a wifi interface, check if this device provides data via
 117          * ethtool (e.g. an Ethernet adapter)
 118          */
 119         memset(&link_settings, 0, sizeof(link_settings));
 120         rtnl_lock();
 121         ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
 122         rtnl_unlock();
 123
 124         /* Virtual interface drivers such as tun / tap interfaces, VLAN, etc
 125          * tend to initialize the interface throughput with some value for the
 126          * sake of having a throughput number to export via ethtool. This
 127          * exported throughput leaves batman-adv to conclude the interface
 128          * throughput is genuine (reflecting reality), thus no measurements
 129          * are necessary.
 130          *
 131          * Based on the observation that those interface types also tend to set
 132          * the link auto-negotiation to 'off', batman-adv shall check this
 133          * setting to differentiate between genuine link throughput information
 134          * and placeholders installed by virtual interfaces.
 135          */
 136         if (ret == 0 && link_settings.base.autoneg == AUTONEG_ENABLE) {
 137                 /* link characteristics might change over time */
 138                 if (link_settings.base.duplex == DUPLEX_FULL)
 139                         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 140                 else
 141                         hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 142
 143                 throughput = link_settings.base.speed;
 144                 if (throughput && throughput != SPEED_UNKNOWN)
 145                         return throughput * 10;
 146         }
 147
 148 default_throughput:
 149         if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
 150                 batadv_info(hard_iface->soft_iface,
 151                             "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",
 152                             hard_iface->net_dev->name,
 153                             BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
 154                             BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
 155                 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
 156         }
 157
 158         /* if none of the above cases apply, return the base_throughput */
 159         return BATADV_THROUGHPUT_DEFAULT_VALUE;
 160 }
 161
 162 /**
 163  * batadv_v_elp_throughput_metric_update() - worker updating the throughput
 164  *  metric of a single hop neighbour
 165  * @work: the work queue item
 166  */
 167 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
 168 {
 169         struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
 170         struct batadv_hardif_neigh_node *neigh;
 171
 172         neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
 173                                    metric_work);
 174         neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
 175                              bat_v);
 176
 177         ewma_throughput_add(&neigh->bat_v.throughput,
 178                             batadv_v_elp_get_throughput(neigh));
 179
 180         /* decrement refcounter to balance increment performed before scheduling
 181          * this task
 182          */
 183         batadv_hardif_neigh_put(neigh);
 184 }
 185
 186 /**
 187  * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
 188  * @neigh: the neighbour to probe
 189  *
 190  * Sends a predefined number of unicast wifi packets to a given neighbour in
 191  * order to trigger the throughput estimation on this link by the RC algorithm.
 192  * Packets are sent only if there there is not enough payload unicast traffic
 193  * towards this neighbour..
 194  *
 195  * Return: True on success and false in case of error during skb preparation.
 196  */
 197 static bool
 198 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
 199 {
 200         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 201         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 202         unsigned long last_tx_diff;
 203         struct sk_buff *skb;
 204         int probe_len, i;
 205         int elp_skb_len;
 206
 207         /* this probing routine is for Wifi neighbours only */
 208         if (!batadv_is_wifi_hardif(hard_iface))
 209                 return true;
 210
 211         /* probe the neighbor only if no unicast packets have been sent
 212          * to it in the last 100 milliseconds: this is the rate control
 213          * algorithm sampling interval (minstrel). In this way, if not
 214          * enough traffic has been sent to the neighbor, batman-adv can
 215          * generate 2 probe packets and push the RC algorithm to perform
 216          * the sampling
 217          */
 218         last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
 219         if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
 220                 return true;
 221
 222         probe_len = max_t(int, sizeof(struct batadv_elp_packet),
 223                           BATADV_ELP_MIN_PROBE_SIZE);
 224
 225         for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
 226                 elp_skb_len = hard_iface->bat_v.elp_skb->len;
 227                 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
 228                                       probe_len - elp_skb_len,
 229                                       GFP_ATOMIC);
 230                 if (!skb)
 231                         return false;
 232
 233                 /* Tell the skb to get as big as the allocated space (we want
 234                  * the packet to be exactly of that size to make the link
 235                  * throughput estimation effective.
 236                  */
 237                 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);
 238
 239                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 240                            "Sending unicast (probe) ELP packet on interface %s to %pM\n",
 241                            hard_iface->net_dev->name, neigh->addr);
 242
 243                 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
 244         }
 245
 246         return true;
 247 }
 248
 249 /**
 250  * batadv_v_elp_periodic_work() - ELP periodic task per interface
 251  * @work: work queue item
 252  *
 253  * Emits broadcast ELP message in regular intervals.
 254  */
 255 static void batadv_v_elp_periodic_work(struct work_struct *work)
 256 {
 257         struct batadv_hardif_neigh_node *hardif_neigh;
 258         struct batadv_hard_iface *hard_iface;
 259         struct batadv_hard_iface_bat_v *bat_v;
 260         struct batadv_elp_packet *elp_packet;
 261         struct batadv_priv *bat_priv;
 262         struct sk_buff *skb;
 263         u32 elp_interval;
 264         bool ret;
 265
 266         bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
 267         hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 268         bat_priv = netdev_priv(hard_iface->soft_iface);
 269
 270         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 271                 goto out;
 272
 273         /* we are in the process of shutting this interface down */
 274         if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
 275             hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
 276                 goto out;
 277
 278         /* the interface was enabled but may not be ready yet */
 279         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 280                 goto restart_timer;
 281
 282         skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
 283         if (!skb)
 284                 goto restart_timer;
 285
 286         elp_packet = (struct batadv_elp_packet *)skb->data;
 287         elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
 288         elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
 289         elp_packet->elp_interval = htonl(elp_interval);
 290
 291         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 292                    "Sending broadcast ELP packet on interface %s, seqno %u\n",
 293                    hard_iface->net_dev->name,
 294                    atomic_read(&hard_iface->bat_v.elp_seqno));
 295
 296         batadv_send_broadcast_skb(skb, hard_iface);
 297
 298         atomic_inc(&hard_iface->bat_v.elp_seqno);
 299
 300         /* The throughput metric is updated on each sent packet. This way, if a
 301          * node is dead and no longer sends packets, batman-adv is still able to
 302          * react timely to its death.
 303          *
 304          * The throughput metric is updated by following these steps:
 305          * 1) if the hard_iface is wifi => send a number of unicast ELPs for
 306          *    probing/sampling to each neighbor
 307          * 2) update the throughput metric value of each neighbor (note that the
 308          *    value retrieved in this step might be 100ms old because the
 309          *    probing packets at point 1) could still be in the HW queue)
 310          */
 311         rcu_read_lock();
 312         hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
 313                 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
 314                         /* if something goes wrong while probing, better to stop
 315                          * sending packets immediately and reschedule the task
 316                          */
 317                         break;
 318
 319                 if (!kref_get_unless_zero(&hardif_neigh->refcount))
 320                         continue;
 321
 322                 /* Reading the estimated throughput from cfg80211 is a task that
 323                  * may sleep and that is not allowed in an rcu protected
 324                  * context. Therefore schedule a task for that.
 325                  */
 326                 ret = queue_work(batadv_event_workqueue,
 327                                  &hardif_neigh->bat_v.metric_work);
 328
 329                 if (!ret)
 330                         batadv_hardif_neigh_put(hardif_neigh);
 331         }
 332         rcu_read_unlock();
 333
 334 restart_timer:
 335         batadv_v_elp_start_timer(hard_iface);
 336 out:
 337         return;
 338 }
 339
 340 /**
 341  * batadv_v_elp_iface_enable() - setup the ELP interface private resources
 342  * @hard_iface: interface for which the data has to be prepared
 343  *
 344  * Return: 0 on success or a -ENOMEM in case of failure.
 345  */
 346 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 347 {
 348         static const size_t tvlv_padding = sizeof(__be32);
 349         struct batadv_elp_packet *elp_packet;
 350         unsigned char *elp_buff;
 351         u32 random_seqno;
 352         size_t size;
 353         int res = -ENOMEM;
 354
 355         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
 356         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 357         if (!hard_iface->bat_v.elp_skb)
 358                 goto out;
 359
 360         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 361         elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
 362                                 BATADV_ELP_HLEN + tvlv_padding);
 363         elp_packet = (struct batadv_elp_packet *)elp_buff;
 364
 365         elp_packet->packet_type = BATADV_ELP;
 366         elp_packet->version = BATADV_COMPAT_VERSION;
 367
 368         /* randomize initial seqno to avoid collision */
 369         get_random_bytes(&random_seqno, sizeof(random_seqno));
 370         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 371
 372         /* assume full-duplex by default */
 373         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 374
 375         /* warn the user (again) if there is no throughput data is available */
 376         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 377
 378         if (batadv_is_wifi_hardif(hard_iface))
 379                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 380
 381         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 382                           batadv_v_elp_periodic_work);
 383         batadv_v_elp_start_timer(hard_iface);
 384         res = 0;
 385
 386 out:
 387         return res;
 388 }
 389
 390 /**
 391  * batadv_v_elp_iface_disable() - release ELP interface private resources
 392  * @hard_iface: interface for which the resources have to be released
 393  */
 394 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 395 {
 396         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 397
 398         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 399         hard_iface->bat_v.elp_skb = NULL;
 400 }
 401
 402 /**
 403  * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
 404  *  hard-interface
 405  * @primary_iface: the new primary interface
 406  * @hard_iface: interface holding the to-be-updated buffer
 407  */
 408 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 409                                  struct batadv_hard_iface *hard_iface)
 410 {
 411         struct batadv_elp_packet *elp_packet;
 412         struct sk_buff *skb;
 413
 414         if (!hard_iface->bat_v.elp_skb)
 415                 return;
 416
 417         skb = hard_iface->bat_v.elp_skb;
 418         elp_packet = (struct batadv_elp_packet *)skb->data;
 419         ether_addr_copy(elp_packet->orig,
 420                         primary_iface->net_dev->dev_addr);
 421 }
 422
 423 /**
 424  * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
 425  *  primary interface
 426  * @primary_iface: the new primary interface
 427  */
 428 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 429 {
 430         struct batadv_hard_iface *hard_iface;
 431
 432         /* update orig field of every elp iface belonging to this mesh */
 433         rcu_read_lock();
 434         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 435                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 436                         continue;
 437
 438                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 439         }
 440         rcu_read_unlock();
 441 }
 442
 443 /**
 444  * batadv_v_elp_neigh_update() - update an ELP neighbour node
 445  * @bat_priv: the bat priv with all the soft interface information
 446  * @neigh_addr: the neighbour interface address
 447  * @if_incoming: the interface the packet was received through
 448  * @elp_packet: the received ELP packet
 449  *
 450  * Updates the ELP neighbour node state with the data received within the new
 451  * ELP packet.
 452  */
 453 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 454                                       u8 *neigh_addr,
 455                                       struct batadv_hard_iface *if_incoming,
 456                                       struct batadv_elp_packet *elp_packet)
 457
 458 {
 459         struct batadv_neigh_node *neigh;
 460         struct batadv_orig_node *orig_neigh;
 461         struct batadv_hardif_neigh_node *hardif_neigh;
 462         s32 seqno_diff;
 463         s32 elp_latest_seqno;
 464
 465         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 466         if (!orig_neigh)
 467                 return;
 468
 469         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 470                                                 if_incoming, neigh_addr);
 471         if (!neigh)
 472                 goto orig_free;
 473
 474         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 475         if (!hardif_neigh)
 476                 goto neigh_free;
 477
 478         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 479         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 480
 481         /* known or older sequence numbers are ignored. However always adopt
 482          * if the router seems to have been restarted.
 483          */
 484         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 485                 goto hardif_free;
 486
 487         neigh->last_seen = jiffies;
 488         hardif_neigh->last_seen = jiffies;
 489         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 490         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 491
 492 hardif_free:
 493         if (hardif_neigh)
 494                 batadv_hardif_neigh_put(hardif_neigh);
 495 neigh_free:
 496         if (neigh)
 497                 batadv_neigh_node_put(neigh);
 498 orig_free:
 499         if (orig_neigh)
 500                 batadv_orig_node_put(orig_neigh);
 501 }
 502
 503 /**
 504  * batadv_v_elp_packet_recv() - main ELP packet handler
 505  * @skb: the received packet
 506  * @if_incoming: the interface this packet was received through
 507  *
 508  * Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly
 509  * processed or NET_RX_DROP in case of failure.
 510  */
 511 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 512                              struct batadv_hard_iface *if_incoming)
 513 {
 514         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 515         struct batadv_elp_packet *elp_packet;
 516         struct batadv_hard_iface *primary_if;
 517         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 518         bool res;
 519         int ret = NET_RX_DROP;
 520
 521         res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 522         if (!res)
 523                 goto free_skb;
 524
 525         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 526                 goto free_skb;
 527
 528         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 529          * that does not have B.A.T.M.A.N. V ELP enabled ?
 530          */
 531         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 532                 goto free_skb;
 533
 534         elp_packet = (struct batadv_elp_packet *)skb->data;
 535
 536         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 537                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 538                    ethhdr->h_source, ntohl(elp_packet->seqno),
 539                    elp_packet->orig);
 540
 541         primary_if = batadv_primary_if_get_selected(bat_priv);
 542         if (!primary_if)
 543                 goto free_skb;
 544
 545         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 546                                   elp_packet);
 547
 548         ret = NET_RX_SUCCESS;
 549         batadv_hardif_put(primary_if);
 550
 551 free_skb:
 552         if (ret == NET_RX_SUCCESS)
 553                 consume_skb(skb);
 554         else
 555                 kfree_skb(skb);
 556
 557         return ret;
 558 }