net/batman-adv/bat_v_elp.c

   1 /* Copyright (C) 2011-2016 B.A.T.M.A.N. contributors:
   2  *
   3  * Linus Lüssing, Marek Lindner
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "bat_v_elp.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/byteorder/generic.h>
  23 #include <linux/errno.h>
  24 #include <linux/etherdevice.h>
  25 #include <linux/ethtool.h>
  26 #include <linux/fs.h>
  27 #include <linux/if_ether.h>
  28 #include <linux/jiffies.h>
  29 #include <linux/kernel.h>
  30 #include <linux/kref.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/random.h>
  33 #include <linux/rculist.h>
  34 #include <linux/rcupdate.h>
  35 #include <linux/rtnetlink.h>
  36 #include <linux/skbuff.h>
  37 #include <linux/stddef.h>
  38 #include <linux/string.h>
  39 #include <linux/types.h>
  40 #include <linux/workqueue.h>
  41 #include <net/cfg80211.h>
  42
  43 #include "bat_algo.h"
  44 #include "bat_v_ogm.h"
  45 #include "hard-interface.h"
  46 #include "log.h"
  47 #include "originator.h"
  48 #include "packet.h"
  49 #include "routing.h"
  50 #include "send.h"
  51
  52 /**
  53  * batadv_v_elp_start_timer - restart timer for ELP periodic work
  54  * @hard_iface: the interface for which the timer has to be reset
  55  */
  56 static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
  57 {
  58         unsigned int msecs;
  59
  60         msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
  61         msecs += prandom_u32() % (2 * BATADV_JITTER);
  62
  63         queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
  64                            msecs_to_jiffies(msecs));
  65 }
  66
  67 /**
  68  * batadv_v_elp_get_throughput - get the throughput towards a neighbour
  69  * @neigh: the neighbour for which the throughput has to be obtained
  70  *
  71  * Return: The throughput towards the given neighbour in multiples of 100kpbs
  72  *         (a value of '1' equals to 0.1Mbps, '10' equals 1Mbps, etc).
  73  */
  74 static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
  75 {
  76         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
  77         struct ethtool_link_ksettings link_settings;
  78         struct station_info sinfo;
  79         u32 throughput;
  80         int ret;
  81
  82         /* if the user specified a customised value for this interface, then
  83          * return it directly
  84          */
  85         throughput =  atomic_read(&hard_iface->bat_v.throughput_override);
  86         if (throughput != 0)
  87                 return throughput;
  88
  89         /* if this is a wireless device, then ask its throughput through
  90          * cfg80211 API
  91          */
  92         if (batadv_is_wifi_netdev(hard_iface->net_dev)) {
  93                 if (hard_iface->net_dev->ieee80211_ptr) {
  94                         ret = cfg80211_get_station(hard_iface->net_dev,
  95                                                    neigh->addr, &sinfo);
  96                         if (ret == -ENOENT) {
  97                                 /* Node is not associated anymore! It would be
  98                                  * possible to delete this neighbor. For now set
  99                                  * the throughput metric to 0.
 100                                  */
 101                                 return 0;
 102                         }
 103                         if (!ret)
 104                                 return sinfo.expected_throughput / 100;
 105                 }
 106
 107                 /* unsupported WiFi driver version */
 108                 goto default_throughput;
 109         }
 110
 111         /* if not a wifi interface, check if this device provides data via
 112          * ethtool (e.g. an Ethernet adapter)
 113          */
 114         memset(&link_settings, 0, sizeof(link_settings));
 115         rtnl_lock();
 116         ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
 117         rtnl_unlock();
 118         if (ret == 0) {
 119                 /* link characteristics might change over time */
 120                 if (link_settings.base.duplex == DUPLEX_FULL)
 121                         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 122                 else
 123                         hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 124
 125                 throughput = link_settings.base.speed;
 126                 if (throughput && (throughput != SPEED_UNKNOWN))
 127                         return throughput * 10;
 128         }
 129
 130 default_throughput:
 131         if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
 132                 batadv_info(hard_iface->soft_iface,
 133                             "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",
 134                             hard_iface->net_dev->name,
 135                             BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
 136                             BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
 137                 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
 138         }
 139
 140         /* if none of the above cases apply, return the base_throughput */
 141         return BATADV_THROUGHPUT_DEFAULT_VALUE;
 142 }
 143
 144 /**
 145  * batadv_v_elp_throughput_metric_update - worker updating the throughput metric
 146  *  of a single hop neighbour
 147  * @work: the work queue item
 148  */
 149 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
 150 {
 151         struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
 152         struct batadv_hardif_neigh_node *neigh;
 153
 154         neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
 155                                    metric_work);
 156         neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
 157                              bat_v);
 158
 159         ewma_throughput_add(&neigh->bat_v.throughput,
 160                             batadv_v_elp_get_throughput(neigh));
 161
 162         /* decrement refcounter to balance increment performed before scheduling
 163          * this task
 164          */
 165         batadv_hardif_neigh_put(neigh);
 166 }
 167
 168 /**
 169  * batadv_v_elp_wifi_neigh_probe - send link probing packets to a neighbour
 170  * @neigh: the neighbour to probe
 171  *
 172  * Sends a predefined number of unicast wifi packets to a given neighbour in
 173  * order to trigger the throughput estimation on this link by the RC algorithm.
 174  * Packets are sent only if there there is not enough payload unicast traffic
 175  * towards this neighbour..
 176  *
 177  * Return: True on success and false in case of error during skb preparation.
 178  */
 179 static bool
 180 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
 181 {
 182         struct batadv_hard_iface *hard_iface = neigh->if_incoming;
 183         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 184         unsigned long last_tx_diff;
 185         struct sk_buff *skb;
 186         int probe_len, i;
 187         int elp_skb_len;
 188
 189         /* this probing routine is for Wifi neighbours only */
 190         if (!batadv_is_wifi_netdev(hard_iface->net_dev))
 191                 return true;
 192
 193         /* probe the neighbor only if no unicast packets have been sent
 194          * to it in the last 100 milliseconds: this is the rate control
 195          * algorithm sampling interval (minstrel). In this way, if not
 196          * enough traffic has been sent to the neighbor, batman-adv can
 197          * generate 2 probe packets and push the RC algorithm to perform
 198          * the sampling
 199          */
 200         last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
 201         if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
 202                 return true;
 203
 204         probe_len = max_t(int, sizeof(struct batadv_elp_packet),
 205                           BATADV_ELP_MIN_PROBE_SIZE);
 206
 207         for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
 208                 elp_skb_len = hard_iface->bat_v.elp_skb->len;
 209                 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
 210                                       probe_len - elp_skb_len,
 211                                       GFP_ATOMIC);
 212                 if (!skb)
 213                         return false;
 214
 215                 /* Tell the skb to get as big as the allocated space (we want
 216                  * the packet to be exactly of that size to make the link
 217                  * throughput estimation effective.
 218                  */
 219                 skb_put(skb, probe_len - hard_iface->bat_v.elp_skb->len);
 220
 221                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 222                            "Sending unicast (probe) ELP packet on interface %s to %pM\n",
 223                            hard_iface->net_dev->name, neigh->addr);
 224
 225                 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
 226         }
 227
 228         return true;
 229 }
 230
 231 /**
 232  * batadv_v_elp_periodic_work - ELP periodic task per interface
 233  * @work: work queue item
 234  *
 235  * Emits broadcast ELP message in regular intervals.
 236  */
 237 static void batadv_v_elp_periodic_work(struct work_struct *work)
 238 {
 239         struct batadv_hardif_neigh_node *hardif_neigh;
 240         struct batadv_hard_iface *hard_iface;
 241         struct batadv_hard_iface_bat_v *bat_v;
 242         struct batadv_elp_packet *elp_packet;
 243         struct batadv_priv *bat_priv;
 244         struct sk_buff *skb;
 245         u32 elp_interval;
 246
 247         bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
 248         hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
 249         bat_priv = netdev_priv(hard_iface->soft_iface);
 250
 251         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 252                 goto out;
 253
 254         /* we are in the process of shutting this interface down */
 255         if ((hard_iface->if_status == BATADV_IF_NOT_IN_USE) ||
 256             (hard_iface->if_status == BATADV_IF_TO_BE_REMOVED))
 257                 goto out;
 258
 259         /* the interface was enabled but may not be ready yet */
 260         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 261                 goto restart_timer;
 262
 263         skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
 264         if (!skb)
 265                 goto restart_timer;
 266
 267         elp_packet = (struct batadv_elp_packet *)skb->data;
 268         elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
 269         elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
 270         elp_packet->elp_interval = htonl(elp_interval);
 271
 272         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 273                    "Sending broadcast ELP packet on interface %s, seqno %u\n",
 274                    hard_iface->net_dev->name,
 275                    atomic_read(&hard_iface->bat_v.elp_seqno));
 276
 277         batadv_send_broadcast_skb(skb, hard_iface);
 278
 279         atomic_inc(&hard_iface->bat_v.elp_seqno);
 280
 281         /* The throughput metric is updated on each sent packet. This way, if a
 282          * node is dead and no longer sends packets, batman-adv is still able to
 283          * react timely to its death.
 284          *
 285          * The throughput metric is updated by following these steps:
 286          * 1) if the hard_iface is wifi => send a number of unicast ELPs for
 287          *    probing/sampling to each neighbor
 288          * 2) update the throughput metric value of each neighbor (note that the
 289          *    value retrieved in this step might be 100ms old because the
 290          *    probing packets at point 1) could still be in the HW queue)
 291          */
 292         rcu_read_lock();
 293         hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
 294                 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
 295                         /* if something goes wrong while probing, better to stop
 296                          * sending packets immediately and reschedule the task
 297                          */
 298                         break;
 299
 300                 if (!kref_get_unless_zero(&hardif_neigh->refcount))
 301                         continue;
 302
 303                 /* Reading the estimated throughput from cfg80211 is a task that
 304                  * may sleep and that is not allowed in an rcu protected
 305                  * context. Therefore schedule a task for that.
 306                  */
 307                 queue_work(batadv_event_workqueue,
 308                            &hardif_neigh->bat_v.metric_work);
 309         }
 310         rcu_read_unlock();
 311
 312 restart_timer:
 313         batadv_v_elp_start_timer(hard_iface);
 314 out:
 315         return;
 316 }
 317
 318 /**
 319  * batadv_v_elp_iface_enable - setup the ELP interface private resources
 320  * @hard_iface: interface for which the data has to be prepared
 321  *
 322  * Return: 0 on success or a -ENOMEM in case of failure.
 323  */
 324 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
 325 {
 326         struct batadv_elp_packet *elp_packet;
 327         unsigned char *elp_buff;
 328         u32 random_seqno;
 329         size_t size;
 330         int res = -ENOMEM;
 331
 332         size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN;
 333         hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
 334         if (!hard_iface->bat_v.elp_skb)
 335                 goto out;
 336
 337         skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
 338         elp_buff = skb_put(hard_iface->bat_v.elp_skb, BATADV_ELP_HLEN);
 339         elp_packet = (struct batadv_elp_packet *)elp_buff;
 340         memset(elp_packet, 0, BATADV_ELP_HLEN);
 341
 342         elp_packet->packet_type = BATADV_ELP;
 343         elp_packet->version = BATADV_COMPAT_VERSION;
 344
 345         /* randomize initial seqno to avoid collision */
 346         get_random_bytes(&random_seqno, sizeof(random_seqno));
 347         atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
 348
 349         /* assume full-duplex by default */
 350         hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
 351
 352         /* warn the user (again) if there is no throughput data is available */
 353         hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
 354
 355         if (batadv_is_wifi_netdev(hard_iface->net_dev))
 356                 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
 357
 358         INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
 359                           batadv_v_elp_periodic_work);
 360         batadv_v_elp_start_timer(hard_iface);
 361         res = 0;
 362
 363 out:
 364         return res;
 365 }
 366
 367 /**
 368  * batadv_v_elp_iface_disable - release ELP interface private resources
 369  * @hard_iface: interface for which the resources have to be released
 370  */
 371 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
 372 {
 373         cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
 374
 375         dev_kfree_skb(hard_iface->bat_v.elp_skb);
 376         hard_iface->bat_v.elp_skb = NULL;
 377 }
 378
 379 /**
 380  * batadv_v_elp_iface_activate - update the ELP buffer belonging to the given
 381  *  hard-interface
 382  * @primary_iface: the new primary interface
 383  * @hard_iface: interface holding the to-be-updated buffer
 384  */
 385 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
 386                                  struct batadv_hard_iface *hard_iface)
 387 {
 388         struct batadv_elp_packet *elp_packet;
 389         struct sk_buff *skb;
 390
 391         if (!hard_iface->bat_v.elp_skb)
 392                 return;
 393
 394         skb = hard_iface->bat_v.elp_skb;
 395         elp_packet = (struct batadv_elp_packet *)skb->data;
 396         ether_addr_copy(elp_packet->orig,
 397                         primary_iface->net_dev->dev_addr);
 398 }
 399
 400 /**
 401  * batadv_v_elp_primary_iface_set - change internal data to reflect the new
 402  *  primary interface
 403  * @primary_iface: the new primary interface
 404  */
 405 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
 406 {
 407         struct batadv_hard_iface *hard_iface;
 408
 409         /* update orig field of every elp iface belonging to this mesh */
 410         rcu_read_lock();
 411         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 412                 if (primary_iface->soft_iface != hard_iface->soft_iface)
 413                         continue;
 414
 415                 batadv_v_elp_iface_activate(primary_iface, hard_iface);
 416         }
 417         rcu_read_unlock();
 418 }
 419
 420 /**
 421  * batadv_v_elp_neigh_update - update an ELP neighbour node
 422  * @bat_priv: the bat priv with all the soft interface information
 423  * @neigh_addr: the neighbour interface address
 424  * @if_incoming: the interface the packet was received through
 425  * @elp_packet: the received ELP packet
 426  *
 427  * Updates the ELP neighbour node state with the data received within the new
 428  * ELP packet.
 429  */
 430 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
 431                                       u8 *neigh_addr,
 432                                       struct batadv_hard_iface *if_incoming,
 433                                       struct batadv_elp_packet *elp_packet)
 434
 435 {
 436         struct batadv_neigh_node *neigh;
 437         struct batadv_orig_node *orig_neigh;
 438         struct batadv_hardif_neigh_node *hardif_neigh;
 439         s32 seqno_diff;
 440         s32 elp_latest_seqno;
 441
 442         orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
 443         if (!orig_neigh)
 444                 return;
 445
 446         neigh = batadv_neigh_node_get_or_create(orig_neigh,
 447                                                 if_incoming, neigh_addr);
 448         if (!neigh)
 449                 goto orig_free;
 450
 451         hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
 452         if (!hardif_neigh)
 453                 goto neigh_free;
 454
 455         elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
 456         seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
 457
 458         /* known or older sequence numbers are ignored. However always adopt
 459          * if the router seems to have been restarted.
 460          */
 461         if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
 462                 goto hardif_free;
 463
 464         neigh->last_seen = jiffies;
 465         hardif_neigh->last_seen = jiffies;
 466         hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
 467         hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
 468
 469 hardif_free:
 470         if (hardif_neigh)
 471                 batadv_hardif_neigh_put(hardif_neigh);
 472 neigh_free:
 473         if (neigh)
 474                 batadv_neigh_node_put(neigh);
 475 orig_free:
 476         if (orig_neigh)
 477                 batadv_orig_node_put(orig_neigh);
 478 }
 479
 480 /**
 481  * batadv_v_elp_packet_recv - main ELP packet handler
 482  * @skb: the received packet
 483  * @if_incoming: the interface this packet was received through
 484  *
 485  * Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly
 486  * processed or NET_RX_DROP in case of failure.
 487  */
 488 int batadv_v_elp_packet_recv(struct sk_buff *skb,
 489                              struct batadv_hard_iface *if_incoming)
 490 {
 491         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 492         struct batadv_elp_packet *elp_packet;
 493         struct batadv_hard_iface *primary_if;
 494         struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
 495         bool ret;
 496
 497         ret = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
 498         if (!ret)
 499                 return NET_RX_DROP;
 500
 501         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 502                 return NET_RX_DROP;
 503
 504         /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
 505          * that does not have B.A.T.M.A.N. V ELP enabled ?
 506          */
 507         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 508                 return NET_RX_DROP;
 509
 510         elp_packet = (struct batadv_elp_packet *)skb->data;
 511
 512         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 513                    "Received ELP packet from %pM seqno %u ORIG: %pM\n",
 514                    ethhdr->h_source, ntohl(elp_packet->seqno),
 515                    elp_packet->orig);
 516
 517         primary_if = batadv_primary_if_get_selected(bat_priv);
 518         if (!primary_if)
 519                 goto out;
 520
 521         batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
 522                                   elp_packet);
 523
 524 out:
 525         if (primary_if)
 526                 batadv_hardif_put(primary_if);
 527         consume_skb(skb);
 528         return NET_RX_SUCCESS;
 529 }