net/batman-adv/bat_v_elp.c

   1 /* Copyright (C) 2011-2017  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/byteorder/generic.h>
  23 #include <linux/errno.h>
  24 #include <linux/etherdevice.h>
  25 #include <linux/ethtool.h>
  26 #include <linux/fs.h>
  27 #include <linux/if_ether.h>
  28 #include <linux/jiffies.h>
  29 #include <linux/kernel.h>
  30 #include <linux/kref.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/random.h>
  33 #include <linux/rculist.h>
  34 #include <linux/rcupdate.h>
  35 #include <linux/rtnetlink.h>
  36 #include <linux/skbuff.h>
  37 #include <linux/stddef.h>
  38 #include <linux/string.h>
  39 #include <linux/types.h>
  40 #include <linux/workqueue.h>
  41 #include <net/cfg80211.h>
  42
  43 #include "bat_algo.h"
  44 #include "bat_v_ogm.h"
  45 #include "hard-interface.h"
  46 #include "log.h"
  47 #include "originator.h"
  48 #include "packet.h"
  49 #include "routing.h"
  50 #include "send.h"
  51
  52 /**
  53  * batadv_v_elp_start_timer - restart timer for ELP periodic work
  54  * @hard_iface: the interface for which the timer has to be reset
  55  */
  56 static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
  57 {
  58         unsigned int msecs;
  59
  60         msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
  61         msecs += prandom_u32() % (2 * BATADV_JITTER);
  62
  63         queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
  64                            msecs_to_jiffies(msecs));
  65 }
  66
  67 /**
  68  * batadv_v_elp_get_throughput - get the throughput towards a neighbour
  69  * @neigh: the neighbour for which the throughput has to be obtained
  70  *
  71  * Return: The throughput towards the given neighbour in multiples of 100kpbs
  72  *         (a value of '1' equals to 0.1Mbps, '10' equals 1Mbps, etc).
  73  */
  74 static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
  75 {
  76         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
  77         struct ethtool_link_ksettings link_settings;
  78         struct net_device *real_netdev;
  79         struct station_info sinfo;
  80         u32 throughput;
  81         int ret;
  82
  83         /* if the user specified a customised value for this interface, then
  84          * return it directly
  85          */
  86         throughput =  atomic_read(&hard_iface->bat_v.throughput_override);
  87         if (throughput != 0)
  88                 return throughput;
  89
  90         /* if this is a wireless device, then ask its throughput through
  91          * cfg80211 API
  92          */
  93         if (batadv_is_wifi_hardif(hard_iface)) {
  94                 if (!batadv_is_cfg80211_hardif(hard_iface))
  95                         /* unsupported WiFi driver version */
  96                         goto default_throughput;
  97
  98                 real_netdev = batadv_get_real_netdev(hard_iface->net_dev);
  99                 if (!real_netdev)
 100                         goto default_throughput;
 101
 102                 ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo);
 103
 104                 dev_put(real_netdev);
 105                 if (ret == -ENOENT) {
 106                         /* Node is not associated anymore! It would be
 107                          * possible to delete this neighbor. For now set
 108                          * the throughput metric to 0.
 109                          */
 110                         return 0;
 111                 }
 112                 if (!ret)
 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         if (ret == 0) {
 124                 /* link characteristics might change over time */
 125                 if (link_settings.base.duplex == DUPLEX_FULL)
 126                         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 127                 else
 128                         hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 129
 130                 throughput = link_settings.base.speed;
 131                 if (throughput && (throughput != SPEED_UNKNOWN))
 132                         return throughput * 10;
 133         }
 134
 135 default_throughput:
 136         if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
 137                 batadv_info(hard_iface->soft_iface,
 138                             "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",
 139                             hard_iface->net_dev->name,
 140                             BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
 141                             BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
 142                 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
 143         }
 144
 145         /* if none of the above cases apply, return the base_throughput */
 146         return BATADV_THROUGHPUT_DEFAULT_VALUE;
 147 }
 148
 149 /**
 150  * batadv_v_elp_throughput_metric_update - worker updating the throughput metric
 151  *  of a single hop neighbour
 152  * @work: the work queue item
 153  */
 154 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
 155 {
 156         struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
 157         struct batadv_hardif_neigh_node *neigh;
 158
 159         neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
 160                                    metric_work);
 161         neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
 162                              bat_v);
 163
 164         ewma_throughput_add(&neigh->bat_v.throughput,
 165                             batadv_v_elp_get_throughput(neigh));
 166
 167         /* decrement refcounter to balance increment performed before scheduling
 168          * this task
 169          */
 170         batadv_hardif_neigh_put(neigh);
 171 }
 172
 173 /**
 174  * batadv_v_elp_wifi_neigh_probe - send link probing packets to a neighbour
 175  * @neigh: the neighbour to probe
 176  *
 177  * Sends a predefined number of unicast wifi packets to a given neighbour in
 178  * order to trigger the throughput estimation on this link by the RC algorithm.
 179  * Packets are sent only if there there is not enough payload unicast traffic
 180  * towards this neighbour..
 181  *
 182  * Return: True on success and false in case of error during skb preparation.
 183  */
 184 static bool
 185 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
 186 {
 187         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 188         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 189         unsigned long last_tx_diff;
 190         struct sk_buff *skb;
 191         int probe_len, i;
 192         int elp_skb_len;
 193
 194         /* this probing routine is for Wifi neighbours only */
 195         if (!batadv_is_wifi_hardif(hard_iface))
 196                 return true;
 197
 198         /* probe the neighbor only if no unicast packets have been sent
 199          * to it in the last 100 milliseconds: this is the rate control
 200          * algorithm sampling interval (minstrel). In this way, if not
 201          * enough traffic has been sent to the neighbor, batman-adv can
 202          * generate 2 probe packets and push the RC algorithm to perform
 203          * the sampling
 204          */
 205         last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
 206         if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
 207                 return true;
 208
 209         probe_len = max_t(int, sizeof(struct batadv_elp_packet),
 210                           BATADV_ELP_MIN_PROBE_SIZE);
 211
 212         for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
 213                 elp_skb_len = hard_iface->bat_v.elp_skb->len;
 214                 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
 215                                       probe_len - elp_skb_len,
 216                                       GFP_ATOMIC);
 217                 if (!skb)
 218                         return false;
 219
 220                 /* Tell the skb to get as big as the allocated space (we want
 221                  * the packet to be exactly of that size to make the link
 222                  * throughput estimation effective.
 223                  */
 224                 skb_put(skb, probe_len - hard_iface->bat_v.elp_skb->len);
 225
 226                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 227                            "Sending unicast (probe) ELP packet on interface %s to %pM\n",
 228                            hard_iface->net_dev->name, neigh->addr);
 229
 230                 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
 231         }
 232
 233         return true;
 234 }
 235
 236 /**
 237  * batadv_v_elp_periodic_work - ELP periodic task per interface
 238  * @work: work queue item
 239  *
 240  * Emits broadcast ELP message in regular intervals.
 241  */
 242 static void batadv_v_elp_periodic_work(struct work_struct *work)
 243 {
 244         struct batadv_hardif_neigh_node *hardif_neigh;
 245         struct batadv_hard_iface *hard_iface;
 246         struct batadv_hard_iface_bat_v *bat_v;
 247         struct batadv_elp_packet *elp_packet;
 248         struct batadv_priv *bat_priv;
 249         struct sk_buff *skb;
 250         u32 elp_interval;
 251
 252         bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
 253         hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 254         bat_priv = netdev_priv(hard_iface->soft_iface);
 255
 256         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 257                 goto out;
 258
 259         /* we are in the process of shutting this interface down */
 260         if ((hard_iface->if_status == BATADV_IF_NOT_IN_USE) ||
 261             (hard_iface->if_status == BATADV_IF_TO_BE_REMOVED))
 262                 goto out;
 263
 264         /* the interface was enabled but may not be ready yet */
 265         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 266                 goto restart_timer;
 267
 268         skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
 269         if (!skb)
 270                 goto restart_timer;
 271
 272         elp_packet = (struct batadv_elp_packet *)skb->data;
 273         elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
 274         elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
 275         elp_packet->elp_interval = htonl(elp_interval);
 276
 277         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 278                    "Sending broadcast ELP packet on interface %s, seqno %u\n",
 279                    hard_iface->net_dev->name,
 280                    atomic_read(&hard_iface->bat_v.elp_seqno));
 281
 282         batadv_send_broadcast_skb(skb, hard_iface);
 283
 284         atomic_inc(&hard_iface->bat_v.elp_seqno);
 285
 286         /* The throughput metric is updated on each sent packet. This way, if a
 287          * node is dead and no longer sends packets, batman-adv is still able to
 288          * react timely to its death.
 289          *
 290          * The throughput metric is updated by following these steps:
 291          * 1) if the hard_iface is wifi => send a number of unicast ELPs for
 292          *    probing/sampling to each neighbor
 293          * 2) update the throughput metric value of each neighbor (note that the
 294          *    value retrieved in this step might be 100ms old because the
 295          *    probing packets at point 1) could still be in the HW queue)
 296          */
 297         rcu_read_lock();
 298         hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
 299                 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
 300                         /* if something goes wrong while probing, better to stop
 301                          * sending packets immediately and reschedule the task
 302                          */
 303                         break;
 304
 305                 if (!kref_get_unless_zero(&hardif_neigh->refcount))
 306                         continue;
 307
 308                 /* Reading the estimated throughput from cfg80211 is a task that
 309                  * may sleep and that is not allowed in an rcu protected
 310                  * context. Therefore schedule a task for that.
 311                  */
 312                 queue_work(batadv_event_workqueue,
 313                            &hardif_neigh->bat_v.metric_work);
 314         }
 315         rcu_read_unlock();
 316
 317 restart_timer:
 318         batadv_v_elp_start_timer(hard_iface);
 319 out:
 320         return;
 321 }
 322
 323 /**
 324  * batadv_v_elp_iface_enable - setup the ELP interface private resources
 325  * @hard_iface: interface for which the data has to be prepared
 326  *
 327  * Return: 0 on success or a -ENOMEM in case of failure.
 328  */
 329 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 330 {
 331         struct batadv_elp_packet *elp_packet;
 332         unsigned char *elp_buff;
 333         u32 random_seqno;
 334         size_t size;
 335         int res = -ENOMEM;
 336
 337         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN;
 338         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 339         if (!hard_iface->bat_v.elp_skb)
 340                 goto out;
 341
 342         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 343         elp_buff = skb_put(hard_iface->bat_v.elp_skb, BATADV_ELP_HLEN);
 344         elp_packet = (struct batadv_elp_packet *)elp_buff;
 345         memset(elp_packet, 0, BATADV_ELP_HLEN);
 346
 347         elp_packet->packet_type = BATADV_ELP;
 348         elp_packet->version = BATADV_COMPAT_VERSION;
 349
 350         /* randomize initial seqno to avoid collision */
 351         get_random_bytes(&random_seqno, sizeof(random_seqno));
 352         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 353
 354         /* assume full-duplex by default */
 355         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 356
 357         /* warn the user (again) if there is no throughput data is available */
 358         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 359
 360         if (batadv_is_wifi_hardif(hard_iface))
 361                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 362
 363         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 364                           batadv_v_elp_periodic_work);
 365         batadv_v_elp_start_timer(hard_iface);
 366         res = 0;
 367
 368 out:
 369         return res;
 370 }
 371
 372 /**
 373  * batadv_v_elp_iface_disable - release ELP interface private resources
 374  * @hard_iface: interface for which the resources have to be released
 375  */
 376 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 377 {
 378         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 379
 380         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 381         hard_iface->bat_v.elp_skb = NULL;
 382 }
 383
 384 /**
 385  * batadv_v_elp_iface_activate - update the ELP buffer belonging to the given
 386  *  hard-interface
 387  * @primary_iface: the new primary interface
 388  * @hard_iface: interface holding the to-be-updated buffer
 389  */
 390 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 391                                  struct batadv_hard_iface *hard_iface)
 392 {
 393         struct batadv_elp_packet *elp_packet;
 394         struct sk_buff *skb;
 395
 396         if (!hard_iface->bat_v.elp_skb)
 397                 return;
 398
 399         skb = hard_iface->bat_v.elp_skb;
 400         elp_packet = (struct batadv_elp_packet *)skb->data;
 401         ether_addr_copy(elp_packet->orig,
 402                         primary_iface->net_dev->dev_addr);
 403 }
 404
 405 /**
 406  * batadv_v_elp_primary_iface_set - change internal data to reflect the new
 407  *  primary interface
 408  * @primary_iface: the new primary interface
 409  */
 410 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 411 {
 412         struct batadv_hard_iface *hard_iface;
 413
 414         /* update orig field of every elp iface belonging to this mesh */
 415         rcu_read_lock();
 416         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 417                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 418                         continue;
 419
 420                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 421         }
 422         rcu_read_unlock();
 423 }
 424
 425 /**
 426  * batadv_v_elp_neigh_update - update an ELP neighbour node
 427  * @bat_priv: the bat priv with all the soft interface information
 428  * @neigh_addr: the neighbour interface address
 429  * @if_incoming: the interface the packet was received through
 430  * @elp_packet: the received ELP packet
 431  *
 432  * Updates the ELP neighbour node state with the data received within the new
 433  * ELP packet.
 434  */
 435 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 436                                       u8 *neigh_addr,
 437                                       struct batadv_hard_iface *if_incoming,
 438                                       struct batadv_elp_packet *elp_packet)
 439
 440 {
 441         struct batadv_neigh_node *neigh;
 442         struct batadv_orig_node *orig_neigh;
 443         struct batadv_hardif_neigh_node *hardif_neigh;
 444         s32 seqno_diff;
 445         s32 elp_latest_seqno;
 446
 447         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 448         if (!orig_neigh)
 449                 return;
 450
 451         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 452                                                 if_incoming, neigh_addr);
 453         if (!neigh)
 454                 goto orig_free;
 455
 456         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 457         if (!hardif_neigh)
 458                 goto neigh_free;
 459
 460         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 461         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 462
 463         /* known or older sequence numbers are ignored. However always adopt
 464          * if the router seems to have been restarted.
 465          */
 466         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 467                 goto hardif_free;
 468
 469         neigh->last_seen = jiffies;
 470         hardif_neigh->last_seen = jiffies;
 471         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 472         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 473
 474 hardif_free:
 475         if (hardif_neigh)
 476                 batadv_hardif_neigh_put(hardif_neigh);
 477 neigh_free:
 478         if (neigh)
 479                 batadv_neigh_node_put(neigh);
 480 orig_free:
 481         if (orig_neigh)
 482                 batadv_orig_node_put(orig_neigh);
 483 }
 484
 485 /**
 486  * batadv_v_elp_packet_recv - main ELP packet handler
 487  * @skb: the received packet
 488  * @if_incoming: the interface this packet was received through
 489  *
 490  * Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly
 491  * processed or NET_RX_DROP in case of failure.
 492  */
 493 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 494                              struct batadv_hard_iface *if_incoming)
 495 {
 496         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 497         struct batadv_elp_packet *elp_packet;
 498         struct batadv_hard_iface *primary_if;
 499         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 500         bool res;
 501         int ret = NET_RX_DROP;
 502
 503         res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 504         if (!res)
 505                 goto free_skb;
 506
 507         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 508                 goto free_skb;
 509
 510         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 511          * that does not have B.A.T.M.A.N. V ELP enabled ?
 512          */
 513         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 514                 goto free_skb;
 515
 516         elp_packet = (struct batadv_elp_packet *)skb->data;
 517
 518         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 519                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 520                    ethhdr->h_source, ntohl(elp_packet->seqno),
 521                    elp_packet->orig);
 522
 523         primary_if = batadv_primary_if_get_selected(bat_priv);
 524         if (!primary_if)
 525                 goto free_skb;
 526
 527         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 528                                   elp_packet);
 529
 530         ret = NET_RX_SUCCESS;
 531         batadv_hardif_put(primary_if);
 532
 533 free_skb:
 534         if (ret == NET_RX_SUCCESS)
 535                 consume_skb(skb);
 536         else
 537                 kfree_skb(skb);
 538
 539         return ret;
 540 }