net/batman-adv/bat_v_elp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2011-2018  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                 dev_put(real_netdev);
 108                 if (ret == -ENOENT) {
 109                         /* Node is not associated anymore! It would be
 110                          * possible to delete this neighbor. For now set
 111                          * the throughput metric to 0.
 112                          */
 113                         return 0;
 114                 }
 115                 if (ret)
 116                         goto default_throughput;
 117                 if (!(sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)))
 118                         goto default_throughput;
 119
 120                 return sinfo.expected_throughput / 100;
 121         }
 122
 123         /* if not a wifi interface, check if this device provides data via
 124          * ethtool (e.g. an Ethernet adapter)
 125          */
 126         memset(&link_settings, 0, sizeof(link_settings));
 127         rtnl_lock();
 128         ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
 129         rtnl_unlock();
 130
 131         /* Virtual interface drivers such as tun / tap interfaces, VLAN, etc
 132          * tend to initialize the interface throughput with some value for the
 133          * sake of having a throughput number to export via ethtool. This
 134          * exported throughput leaves batman-adv to conclude the interface
 135          * throughput is genuine (reflecting reality), thus no measurements
 136          * are necessary.
 137          *
 138          * Based on the observation that those interface types also tend to set
 139          * the link auto-negotiation to 'off', batman-adv shall check this
 140          * setting to differentiate between genuine link throughput information
 141          * and placeholders installed by virtual interfaces.
 142          */
 143         if (ret == 0 && link_settings.base.autoneg == AUTONEG_ENABLE) {
 144                 /* link characteristics might change over time */
 145                 if (link_settings.base.duplex == DUPLEX_FULL)
 146                         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 147                 else
 148                         hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 149
 150                 throughput = link_settings.base.speed;
 151                 if (throughput && throughput != SPEED_UNKNOWN)
 152                         return throughput * 10;
 153         }
 154
 155 default_throughput:
 156         if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
 157                 batadv_info(hard_iface->soft_iface,
 158                             "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",
 159                             hard_iface->net_dev->name,
 160                             BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
 161                             BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
 162                 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
 163         }
 164
 165         /* if none of the above cases apply, return the base_throughput */
 166         return BATADV_THROUGHPUT_DEFAULT_VALUE;
 167 }
 168
 169 /**
 170  * batadv_v_elp_throughput_metric_update() - worker updating the throughput
 171  *  metric of a single hop neighbour
 172  * @work: the work queue item
 173  */
 174 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
 175 {
 176         struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
 177         struct batadv_hardif_neigh_node *neigh;
 178
 179         neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
 180                                    metric_work);
 181         neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
 182                              bat_v);
 183
 184         ewma_throughput_add(&neigh->bat_v.throughput,
 185                             batadv_v_elp_get_throughput(neigh));
 186
 187         /* decrement refcounter to balance increment performed before scheduling
 188          * this task
 189          */
 190         batadv_hardif_neigh_put(neigh);
 191 }
 192
 193 /**
 194  * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
 195  * @neigh: the neighbour to probe
 196  *
 197  * Sends a predefined number of unicast wifi packets to a given neighbour in
 198  * order to trigger the throughput estimation on this link by the RC algorithm.
 199  * Packets are sent only if there there is not enough payload unicast traffic
 200  * towards this neighbour..
 201  *
 202  * Return: True on success and false in case of error during skb preparation.
 203  */
 204 static bool
 205 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
 206 {
 207         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 208         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 209         unsigned long last_tx_diff;
 210         struct sk_buff *skb;
 211         int probe_len, i;
 212         int elp_skb_len;
 213
 214         /* this probing routine is for Wifi neighbours only */
 215         if (!batadv_is_wifi_hardif(hard_iface))
 216                 return true;
 217
 218         /* probe the neighbor only if no unicast packets have been sent
 219          * to it in the last 100 milliseconds: this is the rate control
 220          * algorithm sampling interval (minstrel). In this way, if not
 221          * enough traffic has been sent to the neighbor, batman-adv can
 222          * generate 2 probe packets and push the RC algorithm to perform
 223          * the sampling
 224          */
 225         last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
 226         if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
 227                 return true;
 228
 229         probe_len = max_t(int, sizeof(struct batadv_elp_packet),
 230                           BATADV_ELP_MIN_PROBE_SIZE);
 231
 232         for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
 233                 elp_skb_len = hard_iface->bat_v.elp_skb->len;
 234                 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
 235                                       probe_len - elp_skb_len,
 236                                       GFP_ATOMIC);
 237                 if (!skb)
 238                         return false;
 239
 240                 /* Tell the skb to get as big as the allocated space (we want
 241                  * the packet to be exactly of that size to make the link
 242                  * throughput estimation effective.
 243                  */
 244                 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);
 245
 246                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 247                            "Sending unicast (probe) ELP packet on interface %s to %pM\n",
 248                            hard_iface->net_dev->name, neigh->addr);
 249
 250                 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
 251         }
 252
 253         return true;
 254 }
 255
 256 /**
 257  * batadv_v_elp_periodic_work() - ELP periodic task per interface
 258  * @work: work queue item
 259  *
 260  * Emits broadcast ELP message in regular intervals.
 261  */
 262 static void batadv_v_elp_periodic_work(struct work_struct *work)
 263 {
 264         struct batadv_hardif_neigh_node *hardif_neigh;
 265         struct batadv_hard_iface *hard_iface;
 266         struct batadv_hard_iface_bat_v *bat_v;
 267         struct batadv_elp_packet *elp_packet;
 268         struct batadv_priv *bat_priv;
 269         struct sk_buff *skb;
 270         u32 elp_interval;
 271         bool ret;
 272
 273         bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
 274         hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 275         bat_priv = netdev_priv(hard_iface->soft_iface);
 276
 277         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 278                 goto out;
 279
 280         /* we are in the process of shutting this interface down */
 281         if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
 282             hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
 283                 goto out;
 284
 285         /* the interface was enabled but may not be ready yet */
 286         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 287                 goto restart_timer;
 288
 289         skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
 290         if (!skb)
 291                 goto restart_timer;
 292
 293         elp_packet = (struct batadv_elp_packet *)skb->data;
 294         elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
 295         elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
 296         elp_packet->elp_interval = htonl(elp_interval);
 297
 298         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 299                    "Sending broadcast ELP packet on interface %s, seqno %u\n",
 300                    hard_iface->net_dev->name,
 301                    atomic_read(&hard_iface->bat_v.elp_seqno));
 302
 303         batadv_send_broadcast_skb(skb, hard_iface);
 304
 305         atomic_inc(&hard_iface->bat_v.elp_seqno);
 306
 307         /* The throughput metric is updated on each sent packet. This way, if a
 308          * node is dead and no longer sends packets, batman-adv is still able to
 309          * react timely to its death.
 310          *
 311          * The throughput metric is updated by following these steps:
 312          * 1) if the hard_iface is wifi => send a number of unicast ELPs for
 313          *    probing/sampling to each neighbor
 314          * 2) update the throughput metric value of each neighbor (note that the
 315          *    value retrieved in this step might be 100ms old because the
 316          *    probing packets at point 1) could still be in the HW queue)
 317          */
 318         rcu_read_lock();
 319         hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
 320                 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
 321                         /* if something goes wrong while probing, better to stop
 322                          * sending packets immediately and reschedule the task
 323                          */
 324                         break;
 325
 326                 if (!kref_get_unless_zero(&hardif_neigh->refcount))
 327                         continue;
 328
 329                 /* Reading the estimated throughput from cfg80211 is a task that
 330                  * may sleep and that is not allowed in an rcu protected
 331                  * context. Therefore schedule a task for that.
 332                  */
 333                 ret = queue_work(batadv_event_workqueue,
 334                                  &hardif_neigh->bat_v.metric_work);
 335
 336                 if (!ret)
 337                         batadv_hardif_neigh_put(hardif_neigh);
 338         }
 339         rcu_read_unlock();
 340
 341 restart_timer:
 342         batadv_v_elp_start_timer(hard_iface);
 343 out:
 344         return;
 345 }
 346
 347 /**
 348  * batadv_v_elp_iface_enable() - setup the ELP interface private resources
 349  * @hard_iface: interface for which the data has to be prepared
 350  *
 351  * Return: 0 on success or a -ENOMEM in case of failure.
 352  */
 353 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 354 {
 355         struct batadv_elp_packet *elp_packet;
 356         unsigned char *elp_buff;
 357         u32 random_seqno;
 358         size_t size;
 359         int res = -ENOMEM;
 360
 361         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN;
 362         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 363         if (!hard_iface->bat_v.elp_skb)
 364                 goto out;
 365
 366         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 367         elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb, BATADV_ELP_HLEN);
 368         elp_packet = (struct batadv_elp_packet *)elp_buff;
 369
 370         elp_packet->packet_type = BATADV_ELP;
 371         elp_packet->version = BATADV_COMPAT_VERSION;
 372
 373         /* randomize initial seqno to avoid collision */
 374         get_random_bytes(&random_seqno, sizeof(random_seqno));
 375         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 376
 377         /* assume full-duplex by default */
 378         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 379
 380         /* warn the user (again) if there is no throughput data is available */
 381         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 382
 383         if (batadv_is_wifi_hardif(hard_iface))
 384                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 385
 386         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 387                           batadv_v_elp_periodic_work);
 388         batadv_v_elp_start_timer(hard_iface);
 389         res = 0;
 390
 391 out:
 392         return res;
 393 }
 394
 395 /**
 396  * batadv_v_elp_iface_disable() - release ELP interface private resources
 397  * @hard_iface: interface for which the resources have to be released
 398  */
 399 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 400 {
 401         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 402
 403         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 404         hard_iface->bat_v.elp_skb = NULL;
 405 }
 406
 407 /**
 408  * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
 409  *  hard-interface
 410  * @primary_iface: the new primary interface
 411  * @hard_iface: interface holding the to-be-updated buffer
 412  */
 413 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 414                                  struct batadv_hard_iface *hard_iface)
 415 {
 416         struct batadv_elp_packet *elp_packet;
 417         struct sk_buff *skb;
 418
 419         if (!hard_iface->bat_v.elp_skb)
 420                 return;
 421
 422         skb = hard_iface->bat_v.elp_skb;
 423         elp_packet = (struct batadv_elp_packet *)skb->data;
 424         ether_addr_copy(elp_packet->orig,
 425                         primary_iface->net_dev->dev_addr);
 426 }
 427
 428 /**
 429  * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
 430  *  primary interface
 431  * @primary_iface: the new primary interface
 432  */
 433 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 434 {
 435         struct batadv_hard_iface *hard_iface;
 436
 437         /* update orig field of every elp iface belonging to this mesh */
 438         rcu_read_lock();
 439         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 440                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 441                         continue;
 442
 443                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 444         }
 445         rcu_read_unlock();
 446 }
 447
 448 /**
 449  * batadv_v_elp_neigh_update() - update an ELP neighbour node
 450  * @bat_priv: the bat priv with all the soft interface information
 451  * @neigh_addr: the neighbour interface address
 452  * @if_incoming: the interface the packet was received through
 453  * @elp_packet: the received ELP packet
 454  *
 455  * Updates the ELP neighbour node state with the data received within the new
 456  * ELP packet.
 457  */
 458 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 459                                       u8 *neigh_addr,
 460                                       struct batadv_hard_iface *if_incoming,
 461                                       struct batadv_elp_packet *elp_packet)
 462
 463 {
 464         struct batadv_neigh_node *neigh;
 465         struct batadv_orig_node *orig_neigh;
 466         struct batadv_hardif_neigh_node *hardif_neigh;
 467         s32 seqno_diff;
 468         s32 elp_latest_seqno;
 469
 470         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 471         if (!orig_neigh)
 472                 return;
 473
 474         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 475                                                 if_incoming, neigh_addr);
 476         if (!neigh)
 477                 goto orig_free;
 478
 479         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 480         if (!hardif_neigh)
 481                 goto neigh_free;
 482
 483         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 484         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 485
 486         /* known or older sequence numbers are ignored. However always adopt
 487          * if the router seems to have been restarted.
 488          */
 489         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 490                 goto hardif_free;
 491
 492         neigh->last_seen = jiffies;
 493         hardif_neigh->last_seen = jiffies;
 494         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 495         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 496
 497 hardif_free:
 498         if (hardif_neigh)
 499                 batadv_hardif_neigh_put(hardif_neigh);
 500 neigh_free:
 501         if (neigh)
 502                 batadv_neigh_node_put(neigh);
 503 orig_free:
 504         if (orig_neigh)
 505                 batadv_orig_node_put(orig_neigh);
 506 }
 507
 508 /**
 509  * batadv_v_elp_packet_recv() - main ELP packet handler
 510  * @skb: the received packet
 511  * @if_incoming: the interface this packet was received through
 512  *
 513  * Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly
 514  * processed or NET_RX_DROP in case of failure.
 515  */
 516 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 517                              struct batadv_hard_iface *if_incoming)
 518 {
 519         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 520         struct batadv_elp_packet *elp_packet;
 521         struct batadv_hard_iface *primary_if;
 522         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 523         bool res;
 524         int ret = NET_RX_DROP;
 525
 526         res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 527         if (!res)
 528                 goto free_skb;
 529
 530         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 531                 goto free_skb;
 532
 533         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 534          * that does not have B.A.T.M.A.N. V ELP enabled ?
 535          */
 536         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 537                 goto free_skb;
 538
 539         elp_packet = (struct batadv_elp_packet *)skb->data;
 540
 541         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 542                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 543                    ethhdr->h_source, ntohl(elp_packet->seqno),
 544                    elp_packet->orig);
 545
 546         primary_if = batadv_primary_if_get_selected(bat_priv);
 547         if (!primary_if)
 548                 goto free_skb;
 549
 550         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 551                                   elp_packet);
 552
 553         ret = NET_RX_SUCCESS;
 554         batadv_hardif_put(primary_if);
 555
 556 free_skb:
 557         if (ret == NET_RX_SUCCESS)
 558                 consume_skb(skb);
 559         else
 560                 kfree_skb(skb);
 561
 562         return ret;
 563 }