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