net/batman-adv/bat_v_elp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2011-2017  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
  46 #include "bat_algo.h"
  47 #include "bat_v_ogm.h"
  48 #include "hard-interface.h"
  49 #include "log.h"
  50 #include "originator.h"
  51 #include "packet.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         if (ret == 0) {
 131                 /* link characteristics might change over time */
 132                 if (link_settings.base.duplex == DUPLEX_FULL)
 133                         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 134                 else
 135                         hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 136
 137                 throughput = link_settings.base.speed;
 138                 if (throughput && throughput != SPEED_UNKNOWN)
 139                         return throughput * 10;
 140         }
 141
 142 default_throughput:
 143         if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
 144                 batadv_info(hard_iface->soft_iface,
 145                             "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",
 146                             hard_iface->net_dev->name,
 147                             BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
 148                             BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
 149                 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
 150         }
 151
 152         /* if none of the above cases apply, return the base_throughput */
 153         return BATADV_THROUGHPUT_DEFAULT_VALUE;
 154 }
 155
 156 /**
 157  * batadv_v_elp_throughput_metric_update() - worker updating the throughput
 158  *  metric of a single hop neighbour
 159  * @work: the work queue item
 160  */
 161 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
 162 {
 163         struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
 164         struct batadv_hardif_neigh_node *neigh;
 165
 166         neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
 167                                    metric_work);
 168         neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
 169                              bat_v);
 170
 171         ewma_throughput_add(&neigh->bat_v.throughput,
 172                             batadv_v_elp_get_throughput(neigh));
 173
 174         /* decrement refcounter to balance increment performed before scheduling
 175          * this task
 176          */
 177         batadv_hardif_neigh_put(neigh);
 178 }
 179
 180 /**
 181  * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
 182  * @neigh: the neighbour to probe
 183  *
 184  * Sends a predefined number of unicast wifi packets to a given neighbour in
 185  * order to trigger the throughput estimation on this link by the RC algorithm.
 186  * Packets are sent only if there there is not enough payload unicast traffic
 187  * towards this neighbour..
 188  *
 189  * Return: True on success and false in case of error during skb preparation.
 190  */
 191 static bool
 192 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
 193 {
 194         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 195         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 196         unsigned long last_tx_diff;
 197         struct sk_buff *skb;
 198         int probe_len, i;
 199         int elp_skb_len;
 200
 201         /* this probing routine is for Wifi neighbours only */
 202         if (!batadv_is_wifi_hardif(hard_iface))
 203                 return true;
 204
 205         /* probe the neighbor only if no unicast packets have been sent
 206          * to it in the last 100 milliseconds: this is the rate control
 207          * algorithm sampling interval (minstrel). In this way, if not
 208          * enough traffic has been sent to the neighbor, batman-adv can
 209          * generate 2 probe packets and push the RC algorithm to perform
 210          * the sampling
 211          */
 212         last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
 213         if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
 214                 return true;
 215
 216         probe_len = max_t(int, sizeof(struct batadv_elp_packet),
 217                           BATADV_ELP_MIN_PROBE_SIZE);
 218
 219         for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
 220                 elp_skb_len = hard_iface->bat_v.elp_skb->len;
 221                 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
 222                                       probe_len - elp_skb_len,
 223                                       GFP_ATOMIC);
 224                 if (!skb)
 225                         return false;
 226
 227                 /* Tell the skb to get as big as the allocated space (we want
 228                  * the packet to be exactly of that size to make the link
 229                  * throughput estimation effective.
 230                  */
 231                 skb_put(skb, probe_len - hard_iface->bat_v.elp_skb->len);
 232
 233                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 234                            "Sending unicast (probe) ELP packet on interface %s to %pM\n",
 235                            hard_iface->net_dev->name, neigh->addr);
 236
 237                 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
 238         }
 239
 240         return true;
 241 }
 242
 243 /**
 244  * batadv_v_elp_periodic_work() - ELP periodic task per interface
 245  * @work: work queue item
 246  *
 247  * Emits broadcast ELP message in regular intervals.
 248  */
 249 static void batadv_v_elp_periodic_work(struct work_struct *work)
 250 {
 251         struct batadv_hardif_neigh_node *hardif_neigh;
 252         struct batadv_hard_iface *hard_iface;
 253         struct batadv_hard_iface_bat_v *bat_v;
 254         struct batadv_elp_packet *elp_packet;
 255         struct batadv_priv *bat_priv;
 256         struct sk_buff *skb;
 257         u32 elp_interval;
 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                 queue_work(batadv_event_workqueue,
 320                            &hardif_neigh->bat_v.metric_work);
 321         }
 322         rcu_read_unlock();
 323
 324 restart_timer:
 325         batadv_v_elp_start_timer(hard_iface);
 326 out:
 327         return;
 328 }
 329
 330 /**
 331  * batadv_v_elp_iface_enable() - setup the ELP interface private resources
 332  * @hard_iface: interface for which the data has to be prepared
 333  *
 334  * Return: 0 on success or a -ENOMEM in case of failure.
 335  */
 336 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 337 {
 338         struct batadv_elp_packet *elp_packet;
 339         unsigned char *elp_buff;
 340         u32 random_seqno;
 341         size_t size;
 342         int res = -ENOMEM;
 343
 344         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN;
 345         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 346         if (!hard_iface->bat_v.elp_skb)
 347                 goto out;
 348
 349         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 350         elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb, BATADV_ELP_HLEN);
 351         elp_packet = (struct batadv_elp_packet *)elp_buff;
 352
 353         elp_packet->packet_type = BATADV_ELP;
 354         elp_packet->version = BATADV_COMPAT_VERSION;
 355
 356         /* randomize initial seqno to avoid collision */
 357         get_random_bytes(&random_seqno, sizeof(random_seqno));
 358         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 359
 360         /* assume full-duplex by default */
 361         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 362
 363         /* warn the user (again) if there is no throughput data is available */
 364         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 365
 366         if (batadv_is_wifi_hardif(hard_iface))
 367                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 368
 369         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 370                           batadv_v_elp_periodic_work);
 371         batadv_v_elp_start_timer(hard_iface);
 372         res = 0;
 373
 374 out:
 375         return res;
 376 }
 377
 378 /**
 379  * batadv_v_elp_iface_disable() - release ELP interface private resources
 380  * @hard_iface: interface for which the resources have to be released
 381  */
 382 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 383 {
 384         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 385
 386         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 387         hard_iface->bat_v.elp_skb = NULL;
 388 }
 389
 390 /**
 391  * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
 392  *  hard-interface
 393  * @primary_iface: the new primary interface
 394  * @hard_iface: interface holding the to-be-updated buffer
 395  */
 396 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 397                                  struct batadv_hard_iface *hard_iface)
 398 {
 399         struct batadv_elp_packet *elp_packet;
 400         struct sk_buff *skb;
 401
 402         if (!hard_iface->bat_v.elp_skb)
 403                 return;
 404
 405         skb = hard_iface->bat_v.elp_skb;
 406         elp_packet = (struct batadv_elp_packet *)skb->data;
 407         ether_addr_copy(elp_packet->orig,
 408                         primary_iface->net_dev->dev_addr);
 409 }
 410
 411 /**
 412  * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
 413  *  primary interface
 414  * @primary_iface: the new primary interface
 415  */
 416 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 417 {
 418         struct batadv_hard_iface *hard_iface;
 419
 420         /* update orig field of every elp iface belonging to this mesh */
 421         rcu_read_lock();
 422         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 423                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 424                         continue;
 425
 426                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 427         }
 428         rcu_read_unlock();
 429 }
 430
 431 /**
 432  * batadv_v_elp_neigh_update() - update an ELP neighbour node
 433  * @bat_priv: the bat priv with all the soft interface information
 434  * @neigh_addr: the neighbour interface address
 435  * @if_incoming: the interface the packet was received through
 436  * @elp_packet: the received ELP packet
 437  *
 438  * Updates the ELP neighbour node state with the data received within the new
 439  * ELP packet.
 440  */
 441 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 442                                       u8 *neigh_addr,
 443                                       struct batadv_hard_iface *if_incoming,
 444                                       struct batadv_elp_packet *elp_packet)
 445
 446 {
 447         struct batadv_neigh_node *neigh;
 448         struct batadv_orig_node *orig_neigh;
 449         struct batadv_hardif_neigh_node *hardif_neigh;
 450         s32 seqno_diff;
 451         s32 elp_latest_seqno;
 452
 453         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 454         if (!orig_neigh)
 455                 return;
 456
 457         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 458                                                 if_incoming, neigh_addr);
 459         if (!neigh)
 460                 goto orig_free;
 461
 462         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 463         if (!hardif_neigh)
 464                 goto neigh_free;
 465
 466         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 467         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 468
 469         /* known or older sequence numbers are ignored. However always adopt
 470          * if the router seems to have been restarted.
 471          */
 472         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 473                 goto hardif_free;
 474
 475         neigh->last_seen = jiffies;
 476         hardif_neigh->last_seen = jiffies;
 477         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 478         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 479
 480 hardif_free:
 481         if (hardif_neigh)
 482                 batadv_hardif_neigh_put(hardif_neigh);
 483 neigh_free:
 484         if (neigh)
 485                 batadv_neigh_node_put(neigh);
 486 orig_free:
 487         if (orig_neigh)
 488                 batadv_orig_node_put(orig_neigh);
 489 }
 490
 491 /**
 492  * batadv_v_elp_packet_recv() - main ELP packet handler
 493  * @skb: the received packet
 494  * @if_incoming: the interface this packet was received through
 495  *
 496  * Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly
 497  * processed or NET_RX_DROP in case of failure.
 498  */
 499 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 500                              struct batadv_hard_iface *if_incoming)
 501 {
 502         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 503         struct batadv_elp_packet *elp_packet;
 504         struct batadv_hard_iface *primary_if;
 505         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 506         bool res;
 507         int ret = NET_RX_DROP;
 508
 509         res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 510         if (!res)
 511                 goto free_skb;
 512
 513         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 514                 goto free_skb;
 515
 516         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 517          * that does not have B.A.T.M.A.N. V ELP enabled ?
 518          */
 519         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 520                 goto free_skb;
 521
 522         elp_packet = (struct batadv_elp_packet *)skb->data;
 523
 524         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 525                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 526                    ethhdr->h_source, ntohl(elp_packet->seqno),
 527                    elp_packet->orig);
 528
 529         primary_if = batadv_primary_if_get_selected(bat_priv);
 530         if (!primary_if)
 531                 goto free_skb;
 532
 533         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 534                                   elp_packet);
 535
 536         ret = NET_RX_SUCCESS;
 537         batadv_hardif_put(primary_if);
 538
 539 free_skb:
 540         if (ret == NET_RX_SUCCESS)
 541                 consume_skb(skb);
 542         else
 543                 kfree_skb(skb);
 544
 545         return ret;
 546 }