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