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