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_zero(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         bool ret;
 258
 259         bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
 260         hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 261         bat_priv = netdev_priv(hard_iface->soft_iface);
 262
 263         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 264                 goto out;
 265
 266         /* we are in the process of shutting this interface down */
 267         if ((hard_iface->if_status == BATADV_IF_NOT_IN_USE) ||
 268             (hard_iface->if_status == BATADV_IF_TO_BE_REMOVED))
 269                 goto out;
 270
 271         /* the interface was enabled but may not be ready yet */
 272         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 273                 goto restart_timer;
 274
 275         skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
 276         if (!skb)
 277                 goto restart_timer;
 278
 279         elp_packet = (struct batadv_elp_packet *)skb->data;
 280         elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
 281         elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
 282         elp_packet->elp_interval = htonl(elp_interval);
 283
 284         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 285                    "Sending broadcast ELP packet on interface %s, seqno %u\n",
 286                    hard_iface->net_dev->name,
 287                    atomic_read(&hard_iface->bat_v.elp_seqno));
 288
 289         batadv_send_broadcast_skb(skb, hard_iface);
 290
 291         atomic_inc(&hard_iface->bat_v.elp_seqno);
 292
 293         /* The throughput metric is updated on each sent packet. This way, if a
 294          * node is dead and no longer sends packets, batman-adv is still able to
 295          * react timely to its death.
 296          *
 297          * The throughput metric is updated by following these steps:
 298          * 1) if the hard_iface is wifi => send a number of unicast ELPs for
 299          *    probing/sampling to each neighbor
 300          * 2) update the throughput metric value of each neighbor (note that the
 301          *    value retrieved in this step might be 100ms old because the
 302          *    probing packets at point 1) could still be in the HW queue)
 303          */
 304         rcu_read_lock();
 305         hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
 306                 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
 307                         /* if something goes wrong while probing, better to stop
 308                          * sending packets immediately and reschedule the task
 309                          */
 310                         break;
 311
 312                 if (!kref_get_unless_zero(&hardif_neigh->refcount))
 313                         continue;
 314
 315                 /* Reading the estimated throughput from cfg80211 is a task that
 316                  * may sleep and that is not allowed in an rcu protected
 317                  * context. Therefore schedule a task for that.
 318                  */
 319                 ret = queue_work(batadv_event_workqueue,
 320                                  &hardif_neigh->bat_v.metric_work);
 321
 322                 if (!ret)
 323                         batadv_hardif_neigh_put(hardif_neigh);
 324         }
 325         rcu_read_unlock();
 326
 327 restart_timer:
 328         batadv_v_elp_start_timer(hard_iface);
 329 out:
 330         return;
 331 }
 332
 333 /**
 334  * batadv_v_elp_iface_enable - setup the ELP interface private resources
 335  * @hard_iface: interface for which the data has to be prepared
 336  *
 337  * Return: 0 on success or a -ENOMEM in case of failure.
 338  */
 339 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 340 {
 341         static const size_t tvlv_padding = sizeof(__be32);
 342         struct batadv_elp_packet *elp_packet;
 343         unsigned char *elp_buff;
 344         u32 random_seqno;
 345         size_t size;
 346         int res = -ENOMEM;
 347
 348         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
 349         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 350         if (!hard_iface->bat_v.elp_skb)
 351                 goto out;
 352
 353         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 354         elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
 355                                 BATADV_ELP_HLEN + tvlv_padding);
 356         elp_packet = (struct batadv_elp_packet *)elp_buff;
 357
 358         elp_packet->packet_type = BATADV_ELP;
 359         elp_packet->version = BATADV_COMPAT_VERSION;
 360
 361         /* randomize initial seqno to avoid collision */
 362         get_random_bytes(&random_seqno, sizeof(random_seqno));
 363         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 364
 365         /* assume full-duplex by default */
 366         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 367
 368         /* warn the user (again) if there is no throughput data is available */
 369         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 370
 371         if (batadv_is_wifi_hardif(hard_iface))
 372                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 373
 374         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 375                           batadv_v_elp_periodic_work);
 376         batadv_v_elp_start_timer(hard_iface);
 377         res = 0;
 378
 379 out:
 380         return res;
 381 }
 382
 383 /**
 384  * batadv_v_elp_iface_disable - release ELP interface private resources
 385  * @hard_iface: interface for which the resources have to be released
 386  */
 387 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 388 {
 389         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 390
 391         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 392         hard_iface->bat_v.elp_skb = NULL;
 393 }
 394
 395 /**
 396  * batadv_v_elp_iface_activate - update the ELP buffer belonging to the given
 397  *  hard-interface
 398  * @primary_iface: the new primary interface
 399  * @hard_iface: interface holding the to-be-updated buffer
 400  */
 401 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 402                                  struct batadv_hard_iface *hard_iface)
 403 {
 404         struct batadv_elp_packet *elp_packet;
 405         struct sk_buff *skb;
 406
 407         if (!hard_iface->bat_v.elp_skb)
 408                 return;
 409
 410         skb = hard_iface->bat_v.elp_skb;
 411         elp_packet = (struct batadv_elp_packet *)skb->data;
 412         ether_addr_copy(elp_packet->orig,
 413                         primary_iface->net_dev->dev_addr);
 414 }
 415
 416 /**
 417  * batadv_v_elp_primary_iface_set - change internal data to reflect the new
 418  *  primary interface
 419  * @primary_iface: the new primary interface
 420  */
 421 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 422 {
 423         struct batadv_hard_iface *hard_iface;
 424
 425         /* update orig field of every elp iface belonging to this mesh */
 426         rcu_read_lock();
 427         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 428                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 429                         continue;
 430
 431                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 432         }
 433         rcu_read_unlock();
 434 }
 435
 436 /**
 437  * batadv_v_elp_neigh_update - update an ELP neighbour node
 438  * @bat_priv: the bat priv with all the soft interface information
 439  * @neigh_addr: the neighbour interface address
 440  * @if_incoming: the interface the packet was received through
 441  * @elp_packet: the received ELP packet
 442  *
 443  * Updates the ELP neighbour node state with the data received within the new
 444  * ELP packet.
 445  */
 446 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 447                                       u8 *neigh_addr,
 448                                       struct batadv_hard_iface *if_incoming,
 449                                       struct batadv_elp_packet *elp_packet)
 450
 451 {
 452         struct batadv_neigh_node *neigh;
 453         struct batadv_orig_node *orig_neigh;
 454         struct batadv_hardif_neigh_node *hardif_neigh;
 455         s32 seqno_diff;
 456         s32 elp_latest_seqno;
 457
 458         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 459         if (!orig_neigh)
 460                 return;
 461
 462         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 463                                                 if_incoming, neigh_addr);
 464         if (!neigh)
 465                 goto orig_free;
 466
 467         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 468         if (!hardif_neigh)
 469                 goto neigh_free;
 470
 471         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 472         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 473
 474         /* known or older sequence numbers are ignored. However always adopt
 475          * if the router seems to have been restarted.
 476          */
 477         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 478                 goto hardif_free;
 479
 480         neigh->last_seen = jiffies;
 481         hardif_neigh->last_seen = jiffies;
 482         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 483         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 484
 485 hardif_free:
 486         if (hardif_neigh)
 487                 batadv_hardif_neigh_put(hardif_neigh);
 488 neigh_free:
 489         if (neigh)
 490                 batadv_neigh_node_put(neigh);
 491 orig_free:
 492         if (orig_neigh)
 493                 batadv_orig_node_put(orig_neigh);
 494 }
 495
 496 /**
 497  * batadv_v_elp_packet_recv - main ELP packet handler
 498  * @skb: the received packet
 499  * @if_incoming: the interface this packet was received through
 500  *
 501  * Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly
 502  * processed or NET_RX_DROP in case of failure.
 503  */
 504 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 505                              struct batadv_hard_iface *if_incoming)
 506 {
 507         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 508         struct batadv_elp_packet *elp_packet;
 509         struct batadv_hard_iface *primary_if;
 510         struct ethhdr *ethhdr;
 511         bool res;
 512         int ret = NET_RX_DROP;
 513
 514         res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 515         if (!res)
 516                 goto free_skb;
 517
 518         ethhdr = eth_hdr(skb);
 519         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 520                 goto free_skb;
 521
 522         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 523          * that does not have B.A.T.M.A.N. V ELP enabled ?
 524          */
 525         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 526                 goto free_skb;
 527
 528         elp_packet = (struct batadv_elp_packet *)skb->data;
 529
 530         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 531                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 532                    ethhdr->h_source, ntohl(elp_packet->seqno),
 533                    elp_packet->orig);
 534
 535         primary_if = batadv_primary_if_get_selected(bat_priv);
 536         if (!primary_if)
 537                 goto free_skb;
 538
 539         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 540                                   elp_packet);
 541
 542         ret = NET_RX_SUCCESS;
 543         batadv_hardif_put(primary_if);
 544
 545 free_skb:
 546         if (ret == NET_RX_SUCCESS)
 547                 consume_skb(skb);
 548         else
 549                 kfree_skb(skb);
 550
 551         return ret;
 552 }