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