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                 /* free the TID stats immediately */
 108                 cfg80211_sinfo_release_content(&sinfo);
 109
 110                 dev_put(real_netdev);
 111                 if (ret == -ENOENT) {
 112                         /* Node is not associated anymore! It would be
 113                          * possible to delete this neighbor. For now set
 114                          * the throughput metric to 0.
 115                          */
 116                         return 0;
 117                 }
 118                 if (ret)
 119                         goto default_throughput;
 120                 if (!(sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)))
 121                         goto default_throughput;
 122
 123                 return sinfo.expected_throughput / 100;
 124         }
 125
 126         /* if not a wifi interface, check if this device provides data via
 127          * ethtool (e.g. an Ethernet adapter)
 128          */
 129         memset(&link_settings, 0, sizeof(link_settings));
 130         rtnl_lock();
 131         ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
 132         rtnl_unlock();
 133
 134         /* Virtual interface drivers such as tun / tap interfaces, VLAN, etc
 135          * tend to initialize the interface throughput with some value for the
 136          * sake of having a throughput number to export via ethtool. This
 137          * exported throughput leaves batman-adv to conclude the interface
 138          * throughput is genuine (reflecting reality), thus no measurements
 139          * are necessary.
 140          *
 141          * Based on the observation that those interface types also tend to set
 142          * the link auto-negotiation to 'off', batman-adv shall check this
 143          * setting to differentiate between genuine link throughput information
 144          * and placeholders installed by virtual interfaces.
 145          */
 146         if (ret == 0 && link_settings.base.autoneg == AUTONEG_ENABLE) {
 147                 /* link characteristics might change over time */
 148                 if (link_settings.base.duplex == DUPLEX_FULL)
 149                         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 150                 else
 151                         hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 152
 153                 throughput = link_settings.base.speed;
 154                 if (throughput && throughput != SPEED_UNKNOWN)
 155                         return throughput * 10;
 156         }
 157
 158 default_throughput:
 159         if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
 160                 batadv_info(hard_iface->soft_iface,
 161                             "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",
 162                             hard_iface->net_dev->name,
 163                             BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
 164                             BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
 165                 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
 166         }
 167
 168         /* if none of the above cases apply, return the base_throughput */
 169         return BATADV_THROUGHPUT_DEFAULT_VALUE;
 170 }
 171
 172 /**
 173  * batadv_v_elp_throughput_metric_update() - worker updating the throughput
 174  *  metric of a single hop neighbour
 175  * @work: the work queue item
 176  */
 177 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
 178 {
 179         struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
 180         struct batadv_hardif_neigh_node *neigh;
 181
 182         neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
 183                                    metric_work);
 184         neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
 185                              bat_v);
 186
 187         ewma_throughput_add(&neigh->bat_v.throughput,
 188                             batadv_v_elp_get_throughput(neigh));
 189
 190         /* decrement refcounter to balance increment performed before scheduling
 191          * this task
 192          */
 193         batadv_hardif_neigh_put(neigh);
 194 }
 195
 196 /**
 197  * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
 198  * @neigh: the neighbour to probe
 199  *
 200  * Sends a predefined number of unicast wifi packets to a given neighbour in
 201  * order to trigger the throughput estimation on this link by the RC algorithm.
 202  * Packets are sent only if there there is not enough payload unicast traffic
 203  * towards this neighbour..
 204  *
 205  * Return: True on success and false in case of error during skb preparation.
 206  */
 207 static bool
 208 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
 209 {
 210         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 211         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 212         unsigned long last_tx_diff;
 213         struct sk_buff *skb;
 214         int probe_len, i;
 215         int elp_skb_len;
 216
 217         /* this probing routine is for Wifi neighbours only */
 218         if (!batadv_is_wifi_hardif(hard_iface))
 219                 return true;
 220
 221         /* probe the neighbor only if no unicast packets have been sent
 222          * to it in the last 100 milliseconds: this is the rate control
 223          * algorithm sampling interval (minstrel). In this way, if not
 224          * enough traffic has been sent to the neighbor, batman-adv can
 225          * generate 2 probe packets and push the RC algorithm to perform
 226          * the sampling
 227          */
 228         last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
 229         if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
 230                 return true;
 231
 232         probe_len = max_t(int, sizeof(struct batadv_elp_packet),
 233                           BATADV_ELP_MIN_PROBE_SIZE);
 234
 235         for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
 236                 elp_skb_len = hard_iface->bat_v.elp_skb->len;
 237                 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
 238                                       probe_len - elp_skb_len,
 239                                       GFP_ATOMIC);
 240                 if (!skb)
 241                         return false;
 242
 243                 /* Tell the skb to get as big as the allocated space (we want
 244                  * the packet to be exactly of that size to make the link
 245                  * throughput estimation effective.
 246                  */
 247                 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);
 248
 249                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 250                            "Sending unicast (probe) ELP packet on interface %s to %pM\n",
 251                            hard_iface->net_dev->name, neigh->addr);
 252
 253                 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
 254         }
 255
 256         return true;
 257 }
 258
 259 /**
 260  * batadv_v_elp_periodic_work() - ELP periodic task per interface
 261  * @work: work queue item
 262  *
 263  * Emits broadcast ELP message in regular intervals.
 264  */
 265 static void batadv_v_elp_periodic_work(struct work_struct *work)
 266 {
 267         struct batadv_hardif_neigh_node *hardif_neigh;
 268         struct batadv_hard_iface *hard_iface;
 269         struct batadv_hard_iface_bat_v *bat_v;
 270         struct batadv_elp_packet *elp_packet;
 271         struct batadv_priv *bat_priv;
 272         struct sk_buff *skb;
 273         u32 elp_interval;
 274         bool ret;
 275
 276         bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
 277         hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 278         bat_priv = netdev_priv(hard_iface->soft_iface);
 279
 280         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 281                 goto out;
 282
 283         /* we are in the process of shutting this interface down */
 284         if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
 285             hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
 286                 goto out;
 287
 288         /* the interface was enabled but may not be ready yet */
 289         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 290                 goto restart_timer;
 291
 292         skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
 293         if (!skb)
 294                 goto restart_timer;
 295
 296         elp_packet = (struct batadv_elp_packet *)skb->data;
 297         elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
 298         elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
 299         elp_packet->elp_interval = htonl(elp_interval);
 300
 301         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 302                    "Sending broadcast ELP packet on interface %s, seqno %u\n",
 303                    hard_iface->net_dev->name,
 304                    atomic_read(&hard_iface->bat_v.elp_seqno));
 305
 306         batadv_send_broadcast_skb(skb, hard_iface);
 307
 308         atomic_inc(&hard_iface->bat_v.elp_seqno);
 309
 310         /* The throughput metric is updated on each sent packet. This way, if a
 311          * node is dead and no longer sends packets, batman-adv is still able to
 312          * react timely to its death.
 313          *
 314          * The throughput metric is updated by following these steps:
 315          * 1) if the hard_iface is wifi => send a number of unicast ELPs for
 316          *    probing/sampling to each neighbor
 317          * 2) update the throughput metric value of each neighbor (note that the
 318          *    value retrieved in this step might be 100ms old because the
 319          *    probing packets at point 1) could still be in the HW queue)
 320          */
 321         rcu_read_lock();
 322         hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
 323                 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
 324                         /* if something goes wrong while probing, better to stop
 325                          * sending packets immediately and reschedule the task
 326                          */
 327                         break;
 328
 329                 if (!kref_get_unless_zero(&hardif_neigh->refcount))
 330                         continue;
 331
 332                 /* Reading the estimated throughput from cfg80211 is a task that
 333                  * may sleep and that is not allowed in an rcu protected
 334                  * context. Therefore schedule a task for that.
 335                  */
 336                 ret = queue_work(batadv_event_workqueue,
 337                                  &hardif_neigh->bat_v.metric_work);
 338
 339                 if (!ret)
 340                         batadv_hardif_neigh_put(hardif_neigh);
 341         }
 342         rcu_read_unlock();
 343
 344 restart_timer:
 345         batadv_v_elp_start_timer(hard_iface);
 346 out:
 347         return;
 348 }
 349
 350 /**
 351  * batadv_v_elp_iface_enable() - setup the ELP interface private resources
 352  * @hard_iface: interface for which the data has to be prepared
 353  *
 354  * Return: 0 on success or a -ENOMEM in case of failure.
 355  */
 356 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 357 {
 358         static const size_t tvlv_padding = sizeof(__be32);
 359         struct batadv_elp_packet *elp_packet;
 360         unsigned char *elp_buff;
 361         u32 random_seqno;
 362         size_t size;
 363         int res = -ENOMEM;
 364
 365         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
 366         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 367         if (!hard_iface->bat_v.elp_skb)
 368                 goto out;
 369
 370         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 371         elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
 372                                 BATADV_ELP_HLEN + tvlv_padding);
 373         elp_packet = (struct batadv_elp_packet *)elp_buff;
 374
 375         elp_packet->packet_type = BATADV_ELP;
 376         elp_packet->version = BATADV_COMPAT_VERSION;
 377
 378         /* randomize initial seqno to avoid collision */
 379         get_random_bytes(&random_seqno, sizeof(random_seqno));
 380         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 381
 382         /* assume full-duplex by default */
 383         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 384
 385         /* warn the user (again) if there is no throughput data is available */
 386         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 387
 388         if (batadv_is_wifi_hardif(hard_iface))
 389                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 390
 391         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 392                           batadv_v_elp_periodic_work);
 393         batadv_v_elp_start_timer(hard_iface);
 394         res = 0;
 395
 396 out:
 397         return res;
 398 }
 399
 400 /**
 401  * batadv_v_elp_iface_disable() - release ELP interface private resources
 402  * @hard_iface: interface for which the resources have to be released
 403  */
 404 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 405 {
 406         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 407
 408         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 409         hard_iface->bat_v.elp_skb = NULL;
 410 }
 411
 412 /**
 413  * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
 414  *  hard-interface
 415  * @primary_iface: the new primary interface
 416  * @hard_iface: interface holding the to-be-updated buffer
 417  */
 418 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 419                                  struct batadv_hard_iface *hard_iface)
 420 {
 421         struct batadv_elp_packet *elp_packet;
 422         struct sk_buff *skb;
 423
 424         if (!hard_iface->bat_v.elp_skb)
 425                 return;
 426
 427         skb = hard_iface->bat_v.elp_skb;
 428         elp_packet = (struct batadv_elp_packet *)skb->data;
 429         ether_addr_copy(elp_packet->orig,
 430                         primary_iface->net_dev->dev_addr);
 431 }
 432
 433 /**
 434  * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
 435  *  primary interface
 436  * @primary_iface: the new primary interface
 437  */
 438 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 439 {
 440         struct batadv_hard_iface *hard_iface;
 441
 442         /* update orig field of every elp iface belonging to this mesh */
 443         rcu_read_lock();
 444         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 445                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 446                         continue;
 447
 448                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 449         }
 450         rcu_read_unlock();
 451 }
 452
 453 /**
 454  * batadv_v_elp_neigh_update() - update an ELP neighbour node
 455  * @bat_priv: the bat priv with all the soft interface information
 456  * @neigh_addr: the neighbour interface address
 457  * @if_incoming: the interface the packet was received through
 458  * @elp_packet: the received ELP packet
 459  *
 460  * Updates the ELP neighbour node state with the data received within the new
 461  * ELP packet.
 462  */
 463 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 464                                       u8 *neigh_addr,
 465                                       struct batadv_hard_iface *if_incoming,
 466                                       struct batadv_elp_packet *elp_packet)
 467
 468 {
 469         struct batadv_neigh_node *neigh;
 470         struct batadv_orig_node *orig_neigh;
 471         struct batadv_hardif_neigh_node *hardif_neigh;
 472         s32 seqno_diff;
 473         s32 elp_latest_seqno;
 474
 475         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 476         if (!orig_neigh)
 477                 return;
 478
 479         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 480                                                 if_incoming, neigh_addr);
 481         if (!neigh)
 482                 goto orig_free;
 483
 484         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 485         if (!hardif_neigh)
 486                 goto neigh_free;
 487
 488         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 489         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 490
 491         /* known or older sequence numbers are ignored. However always adopt
 492          * if the router seems to have been restarted.
 493          */
 494         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 495                 goto hardif_free;
 496
 497         neigh->last_seen = jiffies;
 498         hardif_neigh->last_seen = jiffies;
 499         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 500         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 501
 502 hardif_free:
 503         if (hardif_neigh)
 504                 batadv_hardif_neigh_put(hardif_neigh);
 505 neigh_free:
 506         if (neigh)
 507                 batadv_neigh_node_put(neigh);
 508 orig_free:
 509         if (orig_neigh)
 510                 batadv_orig_node_put(orig_neigh);
 511 }
 512
 513 /**
 514  * batadv_v_elp_packet_recv() - main ELP packet handler
 515  * @skb: the received packet
 516  * @if_incoming: the interface this packet was received through
 517  *
 518  * Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly
 519  * processed or NET_RX_DROP in case of failure.
 520  */
 521 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 522                              struct batadv_hard_iface *if_incoming)
 523 {
 524         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 525         struct batadv_elp_packet *elp_packet;
 526         struct batadv_hard_iface *primary_if;
 527         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 528         bool res;
 529         int ret = NET_RX_DROP;
 530
 531         res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 532         if (!res)
 533                 goto free_skb;
 534
 535         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 536                 goto free_skb;
 537
 538         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 539          * that does not have B.A.T.M.A.N. V ELP enabled ?
 540          */
 541         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 542                 goto free_skb;
 543
 544         elp_packet = (struct batadv_elp_packet *)skb->data;
 545
 546         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 547                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 548                    ethhdr->h_source, ntohl(elp_packet->seqno),
 549                    elp_packet->orig);
 550
 551         primary_if = batadv_primary_if_get_selected(bat_priv);
 552         if (!primary_if)
 553                 goto free_skb;
 554
 555         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 556                                   elp_packet);
 557
 558         ret = NET_RX_SUCCESS;
 559         batadv_hardif_put(primary_if);
 560
 561 free_skb:
 562         if (ret == NET_RX_SUCCESS)
 563                 consume_skb(skb);
 564         else
 565                 kfree_skb(skb);
 566
 567         return ret;
 568 }