net/batman-adv/bat_v_elp.c

   1 /* Copyright (C) 2011-2016 B.A.T.M.A.N. contributors:
   2  *
   3  * Linus Lüssing, Marek Lindner
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "bat_v_elp.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/bitops.h>
  23 #include <linux/byteorder/generic.h>
  24 #include <linux/errno.h>
  25 #include <linux/etherdevice.h>
  26 #include <linux/ethtool.h>
  27 #include <linux/fs.h>
  28 #include <linux/if_ether.h>
  29 #include <linux/jiffies.h>
  30 #include <linux/kernel.h>
  31 #include <linux/kref.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/nl80211.h>
  34 #include <linux/random.h>
  35 #include <linux/rculist.h>
  36 #include <linux/rcupdate.h>
  37 #include <linux/rtnetlink.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/stddef.h>
  40 #include <linux/string.h>
  41 #include <linux/types.h>
  42 #include <linux/workqueue.h>
  43 #include <net/cfg80211.h>
  44
  45 #include "bat_algo.h"
  46 #include "bat_v_ogm.h"
  47 #include "hard-interface.h"
  48 #include "log.h"
  49 #include "originator.h"
  50 #include "packet.h"
  51 #include "routing.h"
  52 #include "send.h"
  53
  54 /**
  55  * batadv_v_elp_start_timer - restart timer for ELP periodic work
  56  * @hard_iface: the interface for which the timer has to be reset
  57  */
  58 static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
  59 {
  60         unsigned int msecs;
  61
  62         msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
  63         msecs += prandom_u32() % (2 * BATADV_JITTER);
  64
  65         queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
  66                            msecs_to_jiffies(msecs));
  67 }
  68
  69 /**
  70  * batadv_v_elp_get_throughput - get the throughput towards a neighbour
  71  * @neigh: the neighbour for which the throughput has to be obtained
  72  *
  73  * Return: The throughput towards the given neighbour in multiples of 100kpbs
  74  *         (a value of '1' equals to 0.1Mbps, '10' equals 1Mbps, etc).
  75  */
  76 static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
  77 {
  78         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
  79         struct ethtool_link_ksettings link_settings;
  80         struct station_info sinfo;
  81         u32 throughput;
  82         int ret;
  83
  84         /* if the user specified a customised value for this interface, then
  85          * return it directly
  86          */
  87         throughput =  atomic_read(&hard_iface->bat_v.throughput_override);
  88         if (throughput != 0)
  89                 return throughput;
  90
  91         /* if this is a wireless device, then ask its throughput through
  92          * cfg80211 API
  93          */
  94         if (batadv_is_wifi_netdev(hard_iface->net_dev)) {
  95                 if (hard_iface->net_dev->ieee80211_ptr) {
  96                         ret = cfg80211_get_station(hard_iface->net_dev,
  97                                                    neigh->addr, &sinfo);
  98                         if (ret == -ENOENT) {
  99                                 /* Node is not associated anymore! It would be
 100                                  * possible to delete this neighbor. For now set
 101                                  * the throughput metric to 0.
 102                                  */
 103                                 return 0;
 104                         }
 105                         if (ret)
 106                                 goto default_throughput;
 107                         if (!(sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)))
 108                                 goto default_throughput;
 109
 110                         return sinfo.expected_throughput / 100;
 111                 }
 112
 113                 /* unsupported WiFi driver version */
 114                 goto default_throughput;
 115         }
 116
 117         /* if not a wifi interface, check if this device provides data via
 118          * ethtool (e.g. an Ethernet adapter)
 119          */
 120         memset(&link_settings, 0, sizeof(link_settings));
 121         rtnl_lock();
 122         ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
 123         rtnl_unlock();
 124         if (ret == 0) {
 125                 /* link characteristics might change over time */
 126                 if (link_settings.base.duplex == DUPLEX_FULL)
 127                         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 128                 else
 129                         hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 130
 131                 throughput = link_settings.base.speed;
 132                 if (throughput && (throughput != SPEED_UNKNOWN))
 133                         return throughput * 10;
 134         }
 135
 136 default_throughput:
 137         if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
 138                 batadv_info(hard_iface->soft_iface,
 139                             "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",
 140                             hard_iface->net_dev->name,
 141                             BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
 142                             BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
 143                 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
 144         }
 145
 146         /* if none of the above cases apply, return the base_throughput */
 147         return BATADV_THROUGHPUT_DEFAULT_VALUE;
 148 }
 149
 150 /**
 151  * batadv_v_elp_throughput_metric_update - worker updating the throughput metric
 152  *  of a single hop neighbour
 153  * @work: the work queue item
 154  */
 155 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
 156 {
 157         struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
 158         struct batadv_hardif_neigh_node *neigh;
 159
 160         neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
 161                                    metric_work);
 162         neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
 163                              bat_v);
 164
 165         ewma_throughput_add(&neigh->bat_v.throughput,
 166                             batadv_v_elp_get_throughput(neigh));
 167
 168         /* decrement refcounter to balance increment performed before scheduling
 169          * this task
 170          */
 171         batadv_hardif_neigh_put(neigh);
 172 }
 173
 174 /**
 175  * batadv_v_elp_wifi_neigh_probe - send link probing packets to a neighbour
 176  * @neigh: the neighbour to probe
 177  *
 178  * Sends a predefined number of unicast wifi packets to a given neighbour in
 179  * order to trigger the throughput estimation on this link by the RC algorithm.
 180  * Packets are sent only if there there is not enough payload unicast traffic
 181  * towards this neighbour..
 182  *
 183  * Return: True on success and false in case of error during skb preparation.
 184  */
 185 static bool
 186 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
 187 {
 188         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 189         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 190         unsigned long last_tx_diff;
 191         struct sk_buff *skb;
 192         int probe_len, i;
 193         int elp_skb_len;
 194         void *tmp;
 195
 196         /* this probing routine is for Wifi neighbours only */
 197         if (!batadv_is_wifi_netdev(hard_iface->net_dev))
 198                 return true;
 199
 200         /* probe the neighbor only if no unicast packets have been sent
 201          * to it in the last 100 milliseconds: this is the rate control
 202          * algorithm sampling interval (minstrel). In this way, if not
 203          * enough traffic has been sent to the neighbor, batman-adv can
 204          * generate 2 probe packets and push the RC algorithm to perform
 205          * the sampling
 206          */
 207         last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
 208         if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
 209                 return true;
 210
 211         probe_len = max_t(int, sizeof(struct batadv_elp_packet),
 212                           BATADV_ELP_MIN_PROBE_SIZE);
 213
 214         for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
 215                 elp_skb_len = hard_iface->bat_v.elp_skb->len;
 216                 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
 217                                       probe_len - elp_skb_len,
 218                                       GFP_ATOMIC);
 219                 if (!skb)
 220                         return false;
 221
 222                 /* Tell the skb to get as big as the allocated space (we want
 223                  * the packet to be exactly of that size to make the link
 224                  * throughput estimation effective.
 225                  */
 226                 tmp = skb_put(skb, probe_len - hard_iface->bat_v.elp_skb->len);
 227                 memset(tmp, 0, probe_len - hard_iface->bat_v.elp_skb->len);
 228
 229                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 230                            "Sending unicast (probe) ELP packet on interface %s to %pM\n",
 231                            hard_iface->net_dev->name, neigh->addr);
 232
 233                 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
 234         }
 235
 236         return true;
 237 }
 238
 239 /**
 240  * batadv_v_elp_periodic_work - ELP periodic task per interface
 241  * @work: work queue item
 242  *
 243  * Emits broadcast ELP message in regular intervals.
 244  */
 245 static void batadv_v_elp_periodic_work(struct work_struct *work)
 246 {
 247         struct batadv_hardif_neigh_node *hardif_neigh;
 248         struct batadv_hard_iface *hard_iface;
 249         struct batadv_hard_iface_bat_v *bat_v;
 250         struct batadv_elp_packet *elp_packet;
 251         struct batadv_priv *bat_priv;
 252         struct sk_buff *skb;
 253         u32 elp_interval;
 254         bool ret;
 255
 256         bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
 257         hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 258         bat_priv = netdev_priv(hard_iface->soft_iface);
 259
 260         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 261                 goto out;
 262
 263         /* we are in the process of shutting this interface down */
 264         if ((hard_iface->if_status == BATADV_IF_NOT_IN_USE) ||
 265             (hard_iface->if_status == BATADV_IF_TO_BE_REMOVED))
 266                 goto out;
 267
 268         /* the interface was enabled but may not be ready yet */
 269         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 270                 goto restart_timer;
 271
 272         skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
 273         if (!skb)
 274                 goto restart_timer;
 275
 276         elp_packet = (struct batadv_elp_packet *)skb->data;
 277         elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
 278         elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
 279         elp_packet->elp_interval = htonl(elp_interval);
 280
 281         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 282                    "Sending broadcast ELP packet on interface %s, seqno %u\n",
 283                    hard_iface->net_dev->name,
 284                    atomic_read(&hard_iface->bat_v.elp_seqno));
 285
 286         batadv_send_broadcast_skb(skb, hard_iface);
 287
 288         atomic_inc(&hard_iface->bat_v.elp_seqno);
 289
 290         /* The throughput metric is updated on each sent packet. This way, if a
 291          * node is dead and no longer sends packets, batman-adv is still able to
 292          * react timely to its death.
 293          *
 294          * The throughput metric is updated by following these steps:
 295          * 1) if the hard_iface is wifi => send a number of unicast ELPs for
 296          *    probing/sampling to each neighbor
 297          * 2) update the throughput metric value of each neighbor (note that the
 298          *    value retrieved in this step might be 100ms old because the
 299          *    probing packets at point 1) could still be in the HW queue)
 300          */
 301         rcu_read_lock();
 302         hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
 303                 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
 304                         /* if something goes wrong while probing, better to stop
 305                          * sending packets immediately and reschedule the task
 306                          */
 307                         break;
 308
 309                 if (!kref_get_unless_zero(&hardif_neigh->refcount))
 310                         continue;
 311
 312                 /* Reading the estimated throughput from cfg80211 is a task that
 313                  * may sleep and that is not allowed in an rcu protected
 314                  * context. Therefore schedule a task for that.
 315                  */
 316                 ret = queue_work(batadv_event_workqueue,
 317                                  &hardif_neigh->bat_v.metric_work);
 318
 319                 if (!ret)
 320                         batadv_hardif_neigh_put(hardif_neigh);
 321         }
 322         rcu_read_unlock();
 323
 324 restart_timer:
 325         batadv_v_elp_start_timer(hard_iface);
 326 out:
 327         return;
 328 }
 329
 330 /**
 331  * batadv_v_elp_iface_enable - setup the ELP interface private resources
 332  * @hard_iface: interface for which the data has to be prepared
 333  *
 334  * Return: 0 on success or a -ENOMEM in case of failure.
 335  */
 336 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 337 {
 338         static const size_t tvlv_padding = sizeof(__be32);
 339         struct batadv_elp_packet *elp_packet;
 340         unsigned char *elp_buff;
 341         u32 random_seqno;
 342         size_t size;
 343         int res = -ENOMEM;
 344
 345         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
 346         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 347         if (!hard_iface->bat_v.elp_skb)
 348                 goto out;
 349
 350         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 351         elp_buff = skb_put(hard_iface->bat_v.elp_skb,
 352                            BATADV_ELP_HLEN + tvlv_padding);
 353         elp_packet = (struct batadv_elp_packet *)elp_buff;
 354         memset(elp_packet, 0, BATADV_ELP_HLEN + tvlv_padding);
 355
 356         elp_packet->packet_type = BATADV_ELP;
 357         elp_packet->version = BATADV_COMPAT_VERSION;
 358
 359         /* randomize initial seqno to avoid collision */
 360         get_random_bytes(&random_seqno, sizeof(random_seqno));
 361         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 362
 363         /* assume full-duplex by default */
 364         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 365
 366         /* warn the user (again) if there is no throughput data is available */
 367         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 368
 369         if (batadv_is_wifi_netdev(hard_iface->net_dev))
 370                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 371
 372         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 373                           batadv_v_elp_periodic_work);
 374         batadv_v_elp_start_timer(hard_iface);
 375         res = 0;
 376
 377 out:
 378         return res;
 379 }
 380
 381 /**
 382  * batadv_v_elp_iface_disable - release ELP interface private resources
 383  * @hard_iface: interface for which the resources have to be released
 384  */
 385 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 386 {
 387         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 388
 389         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 390         hard_iface->bat_v.elp_skb = NULL;
 391 }
 392
 393 /**
 394  * batadv_v_elp_iface_activate - update the ELP buffer belonging to the given
 395  *  hard-interface
 396  * @primary_iface: the new primary interface
 397  * @hard_iface: interface holding the to-be-updated buffer
 398  */
 399 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 400                                  struct batadv_hard_iface *hard_iface)
 401 {
 402         struct batadv_elp_packet *elp_packet;
 403         struct sk_buff *skb;
 404
 405         if (!hard_iface->bat_v.elp_skb)
 406                 return;
 407
 408         skb = hard_iface->bat_v.elp_skb;
 409         elp_packet = (struct batadv_elp_packet *)skb->data;
 410         ether_addr_copy(elp_packet->orig,
 411                         primary_iface->net_dev->dev_addr);
 412 }
 413
 414 /**
 415  * batadv_v_elp_primary_iface_set - change internal data to reflect the new
 416  *  primary interface
 417  * @primary_iface: the new primary interface
 418  */
 419 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 420 {
 421         struct batadv_hard_iface *hard_iface;
 422
 423         /* update orig field of every elp iface belonging to this mesh */
 424         rcu_read_lock();
 425         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 426                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 427                         continue;
 428
 429                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 430         }
 431         rcu_read_unlock();
 432 }
 433
 434 /**
 435  * batadv_v_elp_neigh_update - update an ELP neighbour node
 436  * @bat_priv: the bat priv with all the soft interface information
 437  * @neigh_addr: the neighbour interface address
 438  * @if_incoming: the interface the packet was received through
 439  * @elp_packet: the received ELP packet
 440  *
 441  * Updates the ELP neighbour node state with the data received within the new
 442  * ELP packet.
 443  */
 444 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 445                                       u8 *neigh_addr,
 446                                       struct batadv_hard_iface *if_incoming,
 447                                       struct batadv_elp_packet *elp_packet)
 448
 449 {
 450         struct batadv_neigh_node *neigh;
 451         struct batadv_orig_node *orig_neigh;
 452         struct batadv_hardif_neigh_node *hardif_neigh;
 453         s32 seqno_diff;
 454         s32 elp_latest_seqno;
 455
 456         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 457         if (!orig_neigh)
 458                 return;
 459
 460         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 461                                                 if_incoming, neigh_addr);
 462         if (!neigh)
 463                 goto orig_free;
 464
 465         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 466         if (!hardif_neigh)
 467                 goto neigh_free;
 468
 469         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 470         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 471
 472         /* known or older sequence numbers are ignored. However always adopt
 473          * if the router seems to have been restarted.
 474          */
 475         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 476                 goto hardif_free;
 477
 478         neigh->last_seen = jiffies;
 479         hardif_neigh->last_seen = jiffies;
 480         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 481         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 482
 483 hardif_free:
 484         if (hardif_neigh)
 485                 batadv_hardif_neigh_put(hardif_neigh);
 486 neigh_free:
 487         if (neigh)
 488                 batadv_neigh_node_put(neigh);
 489 orig_free:
 490         if (orig_neigh)
 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 peoperly
 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 ret;
 510
 511         ret = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 512         if (!ret)
 513                 return NET_RX_DROP;
 514
 515         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 516                 return NET_RX_DROP;
 517
 518         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 519          * that does not have B.A.T.M.A.N. V ELP enabled ?
 520          */
 521         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 522                 return NET_RX_DROP;
 523
 524         elp_packet = (struct batadv_elp_packet *)skb->data;
 525
 526         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 527                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 528                    ethhdr->h_source, ntohl(elp_packet->seqno),
 529                    elp_packet->orig);
 530
 531         primary_if = batadv_primary_if_get_selected(bat_priv);
 532         if (!primary_if)
 533                 goto out;
 534
 535         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 536                                   elp_packet);
 537
 538 out:
 539         if (primary_if)
 540                 batadv_hardif_put(primary_if);
 541         consume_skb(skb);
 542         return NET_RX_SUCCESS;
 543 }