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  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "bat_v_elp.h"
  20 #include "main.h"
  21
  22 #include <linux/atomic.h>
  23 #include <linux/bitops.h>
  24 #include <linux/byteorder/generic.h>
  25 #include <linux/errno.h>
  26 #include <linux/etherdevice.h>
  27 #include <linux/ethtool.h>
  28 #include <linux/gfp.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/jiffies.h>
  31 #include <linux/kernel.h>
  32 #include <linux/kref.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/nl80211.h>
  35 #include <linux/random.h>
  36 #include <linux/rculist.h>
  37 #include <linux/rcupdate.h>
  38 #include <linux/rtnetlink.h>
  39 #include <linux/skbuff.h>
  40 #include <linux/stddef.h>
  41 #include <linux/string.h>
  42 #include <linux/types.h>
  43 #include <linux/workqueue.h>
  44 #include <net/cfg80211.h>
  45 #include <uapi/linux/batadv_packet.h>
  46
  47 #include "bat_algo.h"
  48 #include "bat_v_ogm.h"
  49 #include "hard-interface.h"
  50 #include "log.h"
  51 #include "originator.h"
  52 #include "routing.h"
  53 #include "send.h"
  54
  55 /**
  56  * batadv_v_elp_start_timer() - restart timer for ELP periodic work
  57  * @hard_iface: the interface for which the timer has to be reset
  58  */
  59 static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
  60 {
  61         unsigned int msecs;
  62
  63         msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
  64         msecs += prandom_u32() % (2 * BATADV_JITTER);
  65
  66         queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
  67                            msecs_to_jiffies(msecs));
  68 }
  69
  70 /**
  71  * batadv_v_elp_get_throughput() - get the throughput towards a neighbour
  72  * @neigh: the neighbour for which the throughput has to be obtained
  73  *
  74  * Return: The throughput towards the given neighbour in multiples of 100kpbs
  75  *         (a value of '1' equals to 0.1Mbps, '10' equals 1Mbps, etc).
  76  */
  77 static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
  78 {
  79         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
  80         struct ethtool_link_ksettings link_settings;
  81         struct net_device *real_netdev;
  82         struct station_info sinfo;
  83         u32 throughput;
  84         int ret;
  85
  86         /* if the user specified a customised value for this interface, then
  87          * return it directly
  88          */
  89         throughput =  atomic_read(&hard_iface->bat_v.throughput_override);
  90         if (throughput != 0)
  91                 return throughput;
  92
  93         /* if this is a wireless device, then ask its throughput through
  94          * cfg80211 API
  95          */
  96         if (batadv_is_wifi_hardif(hard_iface)) {
  97                 if (!batadv_is_cfg80211_hardif(hard_iface))
  98                         /* unsupported WiFi driver version */
  99                         goto default_throughput;
 100
 101                 real_netdev = batadv_get_real_netdev(hard_iface->net_dev);
 102                 if (!real_netdev)
 103                         goto default_throughput;
 104
 105                 ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo);
 106
 107                 if (!ret) {
 108                         /* free the TID stats immediately */
 109                         cfg80211_sinfo_release_content(&sinfo);
 110                 }
 111
 112                 dev_put(real_netdev);
 113                 if (ret == -ENOENT) {
 114                         /* Node is not associated anymore! It would be
 115                          * possible to delete this neighbor. For now set
 116                          * the throughput metric to 0.
 117                          */
 118                         return 0;
 119                 }
 120                 if (ret)
 121                         goto default_throughput;
 122                 if (!(sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)))
 123                         goto default_throughput;
 124
 125                 return sinfo.expected_throughput / 100;
 126         }
 127
 128         /* if not a wifi interface, check if this device provides data via
 129          * ethtool (e.g. an Ethernet adapter)
 130          */
 131         memset(&link_settings, 0, sizeof(link_settings));
 132         rtnl_lock();
 133         ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
 134         rtnl_unlock();
 135
 136         /* Virtual interface drivers such as tun / tap interfaces, VLAN, etc
 137          * tend to initialize the interface throughput with some value for the
 138          * sake of having a throughput number to export via ethtool. This
 139          * exported throughput leaves batman-adv to conclude the interface
 140          * throughput is genuine (reflecting reality), thus no measurements
 141          * are necessary.
 142          *
 143          * Based on the observation that those interface types also tend to set
 144          * the link auto-negotiation to 'off', batman-adv shall check this
 145          * setting to differentiate between genuine link throughput information
 146          * and placeholders installed by virtual interfaces.
 147          */
 148         if (ret == 0 && link_settings.base.autoneg == AUTONEG_ENABLE) {
 149                 /* link characteristics might change over time */
 150                 if (link_settings.base.duplex == DUPLEX_FULL)
 151                         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 152                 else
 153                         hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 154
 155                 throughput = link_settings.base.speed;
 156                 if (throughput && throughput != SPEED_UNKNOWN)
 157                         return throughput * 10;
 158         }
 159
 160 default_throughput:
 161         if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
 162                 batadv_info(hard_iface->soft_iface,
 163                             "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",
 164                             hard_iface->net_dev->name,
 165                             BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
 166                             BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
 167                 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
 168         }
 169
 170         /* if none of the above cases apply, return the base_throughput */
 171         return BATADV_THROUGHPUT_DEFAULT_VALUE;
 172 }
 173
 174 /**
 175  * batadv_v_elp_throughput_metric_update() - worker updating the throughput
 176  *  metric of a single hop neighbour
 177  * @work: the work queue item
 178  */
 179 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
 180 {
 181         struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
 182         struct batadv_hardif_neigh_node *neigh;
 183
 184         neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
 185                                    metric_work);
 186         neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
 187                              bat_v);
 188
 189         ewma_throughput_add(&neigh->bat_v.throughput,
 190                             batadv_v_elp_get_throughput(neigh));
 191
 192         /* decrement refcounter to balance increment performed before scheduling
 193          * this task
 194          */
 195         batadv_hardif_neigh_put(neigh);
 196 }
 197
 198 /**
 199  * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
 200  * @neigh: the neighbour to probe
 201  *
 202  * Sends a predefined number of unicast wifi packets to a given neighbour in
 203  * order to trigger the throughput estimation on this link by the RC algorithm.
 204  * Packets are sent only if there there is not enough payload unicast traffic
 205  * towards this neighbour..
 206  *
 207  * Return: True on success and false in case of error during skb preparation.
 208  */
 209 static bool
 210 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
 211 {
 212         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 213         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 214         unsigned long last_tx_diff;
 215         struct sk_buff *skb;
 216         int probe_len, i;
 217         int elp_skb_len;
 218
 219         /* this probing routine is for Wifi neighbours only */
 220         if (!batadv_is_wifi_hardif(hard_iface))
 221                 return true;
 222
 223         /* probe the neighbor only if no unicast packets have been sent
 224          * to it in the last 100 milliseconds: this is the rate control
 225          * algorithm sampling interval (minstrel). In this way, if not
 226          * enough traffic has been sent to the neighbor, batman-adv can
 227          * generate 2 probe packets and push the RC algorithm to perform
 228          * the sampling
 229          */
 230         last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
 231         if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
 232                 return true;
 233
 234         probe_len = max_t(int, sizeof(struct batadv_elp_packet),
 235                           BATADV_ELP_MIN_PROBE_SIZE);
 236
 237         for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
 238                 elp_skb_len = hard_iface->bat_v.elp_skb->len;
 239                 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
 240                                       probe_len - elp_skb_len,
 241                                       GFP_ATOMIC);
 242                 if (!skb)
 243                         return false;
 244
 245                 /* Tell the skb to get as big as the allocated space (we want
 246                  * the packet to be exactly of that size to make the link
 247                  * throughput estimation effective.
 248                  */
 249                 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);
 250
 251                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 252                            "Sending unicast (probe) ELP packet on interface %s to %pM\n",
 253                            hard_iface->net_dev->name, neigh->addr);
 254
 255                 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
 256         }
 257
 258         return true;
 259 }
 260
 261 /**
 262  * batadv_v_elp_periodic_work() - ELP periodic task per interface
 263  * @work: work queue item
 264  *
 265  * Emits broadcast ELP message in regular intervals.
 266  */
 267 static void batadv_v_elp_periodic_work(struct work_struct *work)
 268 {
 269         struct batadv_hardif_neigh_node *hardif_neigh;
 270         struct batadv_hard_iface *hard_iface;
 271         struct batadv_hard_iface_bat_v *bat_v;
 272         struct batadv_elp_packet *elp_packet;
 273         struct batadv_priv *bat_priv;
 274         struct sk_buff *skb;
 275         u32 elp_interval;
 276         bool ret;
 277
 278         bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
 279         hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 280         bat_priv = netdev_priv(hard_iface->soft_iface);
 281
 282         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 283                 goto out;
 284
 285         /* we are in the process of shutting this interface down */
 286         if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
 287             hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
 288                 goto out;
 289
 290         /* the interface was enabled but may not be ready yet */
 291         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 292                 goto restart_timer;
 293
 294         skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
 295         if (!skb)
 296                 goto restart_timer;
 297
 298         elp_packet = (struct batadv_elp_packet *)skb->data;
 299         elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
 300         elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
 301         elp_packet->elp_interval = htonl(elp_interval);
 302
 303         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 304                    "Sending broadcast ELP packet on interface %s, seqno %u\n",
 305                    hard_iface->net_dev->name,
 306                    atomic_read(&hard_iface->bat_v.elp_seqno));
 307
 308         batadv_send_broadcast_skb(skb, hard_iface);
 309
 310         atomic_inc(&hard_iface->bat_v.elp_seqno);
 311
 312         /* The throughput metric is updated on each sent packet. This way, if a
 313          * node is dead and no longer sends packets, batman-adv is still able to
 314          * react timely to its death.
 315          *
 316          * The throughput metric is updated by following these steps:
 317          * 1) if the hard_iface is wifi => send a number of unicast ELPs for
 318          *    probing/sampling to each neighbor
 319          * 2) update the throughput metric value of each neighbor (note that the
 320          *    value retrieved in this step might be 100ms old because the
 321          *    probing packets at point 1) could still be in the HW queue)
 322          */
 323         rcu_read_lock();
 324         hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
 325                 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
 326                         /* if something goes wrong while probing, better to stop
 327                          * sending packets immediately and reschedule the task
 328                          */
 329                         break;
 330
 331                 if (!kref_get_unless_zero(&hardif_neigh->refcount))
 332                         continue;
 333
 334                 /* Reading the estimated throughput from cfg80211 is a task that
 335                  * may sleep and that is not allowed in an rcu protected
 336                  * context. Therefore schedule a task for that.
 337                  */
 338                 ret = queue_work(batadv_event_workqueue,
 339                                  &hardif_neigh->bat_v.metric_work);
 340
 341                 if (!ret)
 342                         batadv_hardif_neigh_put(hardif_neigh);
 343         }
 344         rcu_read_unlock();
 345
 346 restart_timer:
 347         batadv_v_elp_start_timer(hard_iface);
 348 out:
 349         return;
 350 }
 351
 352 /**
 353  * batadv_v_elp_iface_enable() - setup the ELP interface private resources
 354  * @hard_iface: interface for which the data has to be prepared
 355  *
 356  * Return: 0 on success or a -ENOMEM in case of failure.
 357  */
 358 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 359 {
 360         static const size_t tvlv_padding = sizeof(__be32);
 361         struct batadv_elp_packet *elp_packet;
 362         unsigned char *elp_buff;
 363         u32 random_seqno;
 364         size_t size;
 365         int res = -ENOMEM;
 366
 367         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
 368         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 369         if (!hard_iface->bat_v.elp_skb)
 370                 goto out;
 371
 372         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 373         elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
 374                                 BATADV_ELP_HLEN + tvlv_padding);
 375         elp_packet = (struct batadv_elp_packet *)elp_buff;
 376
 377         elp_packet->packet_type = BATADV_ELP;
 378         elp_packet->version = BATADV_COMPAT_VERSION;
 379
 380         /* randomize initial seqno to avoid collision */
 381         get_random_bytes(&random_seqno, sizeof(random_seqno));
 382         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 383
 384         /* assume full-duplex by default */
 385         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 386
 387         /* warn the user (again) if there is no throughput data is available */
 388         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 389
 390         if (batadv_is_wifi_hardif(hard_iface))
 391                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 392
 393         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 394                           batadv_v_elp_periodic_work);
 395         batadv_v_elp_start_timer(hard_iface);
 396         res = 0;
 397
 398 out:
 399         return res;
 400 }
 401
 402 /**
 403  * batadv_v_elp_iface_disable() - release ELP interface private resources
 404  * @hard_iface: interface for which the resources have to be released
 405  */
 406 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 407 {
 408         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 409
 410         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 411         hard_iface->bat_v.elp_skb = NULL;
 412 }
 413
 414 /**
 415  * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
 416  *  hard-interface
 417  * @primary_iface: the new primary interface
 418  * @hard_iface: interface holding the to-be-updated buffer
 419  */
 420 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 421                                  struct batadv_hard_iface *hard_iface)
 422 {
 423         struct batadv_elp_packet *elp_packet;
 424         struct sk_buff *skb;
 425
 426         if (!hard_iface->bat_v.elp_skb)
 427                 return;
 428
 429         skb = hard_iface->bat_v.elp_skb;
 430         elp_packet = (struct batadv_elp_packet *)skb->data;
 431         ether_addr_copy(elp_packet->orig,
 432                         primary_iface->net_dev->dev_addr);
 433 }
 434
 435 /**
 436  * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
 437  *  primary interface
 438  * @primary_iface: the new primary interface
 439  */
 440 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 441 {
 442         struct batadv_hard_iface *hard_iface;
 443
 444         /* update orig field of every elp iface belonging to this mesh */
 445         rcu_read_lock();
 446         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 447                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 448                         continue;
 449
 450                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 451         }
 452         rcu_read_unlock();
 453 }
 454
 455 /**
 456  * batadv_v_elp_neigh_update() - update an ELP neighbour node
 457  * @bat_priv: the bat priv with all the soft interface information
 458  * @neigh_addr: the neighbour interface address
 459  * @if_incoming: the interface the packet was received through
 460  * @elp_packet: the received ELP packet
 461  *
 462  * Updates the ELP neighbour node state with the data received within the new
 463  * ELP packet.
 464  */
 465 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 466                                       u8 *neigh_addr,
 467                                       struct batadv_hard_iface *if_incoming,
 468                                       struct batadv_elp_packet *elp_packet)
 469
 470 {
 471         struct batadv_neigh_node *neigh;
 472         struct batadv_orig_node *orig_neigh;
 473         struct batadv_hardif_neigh_node *hardif_neigh;
 474         s32 seqno_diff;
 475         s32 elp_latest_seqno;
 476
 477         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 478         if (!orig_neigh)
 479                 return;
 480
 481         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 482                                                 if_incoming, neigh_addr);
 483         if (!neigh)
 484                 goto orig_free;
 485
 486         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 487         if (!hardif_neigh)
 488                 goto neigh_free;
 489
 490         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 491         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 492
 493         /* known or older sequence numbers are ignored. However always adopt
 494          * if the router seems to have been restarted.
 495          */
 496         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 497                 goto hardif_free;
 498
 499         neigh->last_seen = jiffies;
 500         hardif_neigh->last_seen = jiffies;
 501         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 502         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 503
 504 hardif_free:
 505         if (hardif_neigh)
 506                 batadv_hardif_neigh_put(hardif_neigh);
 507 neigh_free:
 508         if (neigh)
 509                 batadv_neigh_node_put(neigh);
 510 orig_free:
 511         if (orig_neigh)
 512                 batadv_orig_node_put(orig_neigh);
 513 }
 514
 515 /**
 516  * batadv_v_elp_packet_recv() - main ELP packet handler
 517  * @skb: the received packet
 518  * @if_incoming: the interface this packet was received through
 519  *
 520  * Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly
 521  * processed or NET_RX_DROP in case of failure.
 522  */
 523 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 524                              struct batadv_hard_iface *if_incoming)
 525 {
 526         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 527         struct batadv_elp_packet *elp_packet;
 528         struct batadv_hard_iface *primary_if;
 529         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 530         bool res;
 531         int ret = NET_RX_DROP;
 532
 533         res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 534         if (!res)
 535                 goto free_skb;
 536
 537         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 538                 goto free_skb;
 539
 540         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 541          * that does not have B.A.T.M.A.N. V ELP enabled ?
 542          */
 543         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 544                 goto free_skb;
 545
 546         elp_packet = (struct batadv_elp_packet *)skb->data;
 547
 548         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 549                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 550                    ethhdr->h_source, ntohl(elp_packet->seqno),
 551                    elp_packet->orig);
 552
 553         primary_if = batadv_primary_if_get_selected(bat_priv);
 554         if (!primary_if)
 555                 goto free_skb;
 556
 557         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 558                                   elp_packet);
 559
 560         ret = NET_RX_SUCCESS;
 561         batadv_hardif_put(primary_if);
 562
 563 free_skb:
 564         if (ret == NET_RX_SUCCESS)
 565                 consume_skb(skb);
 566         else
 567                 kfree_skb(skb);
 568
 569         return ret;
 570 }