net/batman-adv/bat_v_ogm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2013-2020  B.A.T.M.A.N. contributors:
   3  *
   4  * Antonio Quartulli
   5  */
   6
   7 #include "bat_v_ogm.h"
   8 #include "main.h"
   9
  10 #include <linux/atomic.h>
  11 #include <linux/byteorder/generic.h>
  12 #include <linux/errno.h>
  13 #include <linux/etherdevice.h>
  14 #include <linux/gfp.h>
  15 #include <linux/if_ether.h>
  16 #include <linux/jiffies.h>
  17 #include <linux/kernel.h>
  18 #include <linux/kref.h>
  19 #include <linux/list.h>
  20 #include <linux/lockdep.h>
  21 #include <linux/mutex.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/prandom.h>
  24 #include <linux/random.h>
  25 #include <linux/rculist.h>
  26 #include <linux/rcupdate.h>
  27 #include <linux/skbuff.h>
  28 #include <linux/slab.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/stddef.h>
  31 #include <linux/string.h>
  32 #include <linux/types.h>
  33 #include <linux/workqueue.h>
  34 #include <uapi/linux/batadv_packet.h>
  35
  36 #include "bat_algo.h"
  37 #include "hard-interface.h"
  38 #include "hash.h"
  39 #include "log.h"
  40 #include "originator.h"
  41 #include "routing.h"
  42 #include "send.h"
  43 #include "translation-table.h"
  44 #include "tvlv.h"
  45
  46 /**
  47  * batadv_v_ogm_orig_get() - retrieve and possibly create an originator node
  48  * @bat_priv: the bat priv with all the soft interface information
  49  * @addr: the address of the originator
  50  *
  51  * Return: the orig_node corresponding to the specified address. If such an
  52  * object does not exist, it is allocated here. In case of allocation failure
  53  * returns NULL.
  54  */
  55 struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv,
  56                                                const u8 *addr)
  57 {
  58         struct batadv_orig_node *orig_node;
  59         int hash_added;
  60
  61         orig_node = batadv_orig_hash_find(bat_priv, addr);
  62         if (orig_node)
  63                 return orig_node;
  64
  65         orig_node = batadv_orig_node_new(bat_priv, addr);
  66         if (!orig_node)
  67                 return NULL;
  68
  69         kref_get(&orig_node->refcount);
  70         hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
  71                                      batadv_choose_orig, orig_node,
  72                                      &orig_node->hash_entry);
  73         if (hash_added != 0) {
  74                 /* remove refcnt for newly created orig_node and hash entry */
  75                 batadv_orig_node_put(orig_node);
  76                 batadv_orig_node_put(orig_node);
  77                 orig_node = NULL;
  78         }
  79
  80         return orig_node;
  81 }
  82
  83 /**
  84  * batadv_v_ogm_start_queue_timer() - restart the OGM aggregation timer
  85  * @hard_iface: the interface to use to send the OGM
  86  */
  87 static void batadv_v_ogm_start_queue_timer(struct batadv_hard_iface *hard_iface)
  88 {
  89         unsigned int msecs = BATADV_MAX_AGGREGATION_MS * 1000;
  90
  91         /* msecs * [0.9, 1.1] */
  92         msecs += prandom_u32_max(msecs / 5) - (msecs / 10);
  93         queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.aggr_wq,
  94                            msecs_to_jiffies(msecs / 1000));
  95 }
  96
  97 /**
  98  * batadv_v_ogm_start_timer() - restart the OGM sending timer
  99  * @bat_priv: the bat priv with all the soft interface information
 100  */
 101 static void batadv_v_ogm_start_timer(struct batadv_priv *bat_priv)
 102 {
 103         unsigned long msecs;
 104         /* this function may be invoked in different contexts (ogm rescheduling
 105          * or hard_iface activation), but the work timer should not be reset
 106          */
 107         if (delayed_work_pending(&bat_priv->bat_v.ogm_wq))
 108                 return;
 109
 110         msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER;
 111         msecs += prandom_u32_max(2 * BATADV_JITTER);
 112         queue_delayed_work(batadv_event_workqueue, &bat_priv->bat_v.ogm_wq,
 113                            msecs_to_jiffies(msecs));
 114 }
 115
 116 /**
 117  * batadv_v_ogm_send_to_if() - send a batman ogm using a given interface
 118  * @skb: the OGM to send
 119  * @hard_iface: the interface to use to send the OGM
 120  */
 121 static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
 122                                     struct batadv_hard_iface *hard_iface)
 123 {
 124         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 125
 126         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 127                 return;
 128
 129         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
 130         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
 131                            skb->len + ETH_HLEN);
 132
 133         batadv_send_broadcast_skb(skb, hard_iface);
 134 }
 135
 136 /**
 137  * batadv_v_ogm_len() - OGMv2 packet length
 138  * @skb: the OGM to check
 139  *
 140  * Return: Length of the given OGMv2 packet, including tvlv length, excluding
 141  * ethernet header length.
 142  */
 143 static unsigned int batadv_v_ogm_len(struct sk_buff *skb)
 144 {
 145         struct batadv_ogm2_packet *ogm_packet;
 146
 147         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 148         return BATADV_OGM2_HLEN + ntohs(ogm_packet->tvlv_len);
 149 }
 150
 151 /**
 152  * batadv_v_ogm_queue_left() - check if given OGM still fits aggregation queue
 153  * @skb: the OGM to check
 154  * @hard_iface: the interface to use to send the OGM
 155  *
 156  * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
 157  *
 158  * Return: True, if the given OGMv2 packet still fits, false otherwise.
 159  */
 160 static bool batadv_v_ogm_queue_left(struct sk_buff *skb,
 161                                     struct batadv_hard_iface *hard_iface)
 162 {
 163         unsigned int max = min_t(unsigned int, hard_iface->net_dev->mtu,
 164                                  BATADV_MAX_AGGREGATION_BYTES);
 165         unsigned int ogm_len = batadv_v_ogm_len(skb);
 166
 167         lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);
 168
 169         return hard_iface->bat_v.aggr_len + ogm_len <= max;
 170 }
 171
 172 /**
 173  * batadv_v_ogm_aggr_list_free - free all elements in an aggregation queue
 174  * @hard_iface: the interface holding the aggregation queue
 175  *
 176  * Empties the OGMv2 aggregation queue and frees all the skbs it contains.
 177  *
 178  * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
 179  */
 180 static void batadv_v_ogm_aggr_list_free(struct batadv_hard_iface *hard_iface)
 181 {
 182         lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);
 183
 184         __skb_queue_purge(&hard_iface->bat_v.aggr_list);
 185         hard_iface->bat_v.aggr_len = 0;
 186 }
 187
 188 /**
 189  * batadv_v_ogm_aggr_send() - flush & send aggregation queue
 190  * @hard_iface: the interface with the aggregation queue to flush
 191  *
 192  * Aggregates all OGMv2 packets currently in the aggregation queue into a
 193  * single OGMv2 packet and transmits this aggregate.
 194  *
 195  * The aggregation queue is empty after this call.
 196  *
 197  * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
 198  */
 199 static void batadv_v_ogm_aggr_send(struct batadv_hard_iface *hard_iface)
 200 {
 201         unsigned int aggr_len = hard_iface->bat_v.aggr_len;
 202         struct sk_buff *skb_aggr;
 203         unsigned int ogm_len;
 204         struct sk_buff *skb;
 205
 206         lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);
 207
 208         if (!aggr_len)
 209                 return;
 210
 211         skb_aggr = dev_alloc_skb(aggr_len + ETH_HLEN + NET_IP_ALIGN);
 212         if (!skb_aggr) {
 213                 batadv_v_ogm_aggr_list_free(hard_iface);
 214                 return;
 215         }
 216
 217         skb_reserve(skb_aggr, ETH_HLEN + NET_IP_ALIGN);
 218         skb_reset_network_header(skb_aggr);
 219
 220         while ((skb = __skb_dequeue(&hard_iface->bat_v.aggr_list))) {
 221                 hard_iface->bat_v.aggr_len -= batadv_v_ogm_len(skb);
 222
 223                 ogm_len = batadv_v_ogm_len(skb);
 224                 skb_put_data(skb_aggr, skb->data, ogm_len);
 225
 226                 consume_skb(skb);
 227         }
 228
 229         batadv_v_ogm_send_to_if(skb_aggr, hard_iface);
 230 }
 231
 232 /**
 233  * batadv_v_ogm_queue_on_if() - queue a batman ogm on a given interface
 234  * @skb: the OGM to queue
 235  * @hard_iface: the interface to queue the OGM on
 236  */
 237 static void batadv_v_ogm_queue_on_if(struct sk_buff *skb,
 238                                      struct batadv_hard_iface *hard_iface)
 239 {
 240         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 241
 242         if (!atomic_read(&bat_priv->aggregated_ogms)) {
 243                 batadv_v_ogm_send_to_if(skb, hard_iface);
 244                 return;
 245         }
 246
 247         spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
 248         if (!batadv_v_ogm_queue_left(skb, hard_iface))
 249                 batadv_v_ogm_aggr_send(hard_iface);
 250
 251         hard_iface->bat_v.aggr_len += batadv_v_ogm_len(skb);
 252         __skb_queue_tail(&hard_iface->bat_v.aggr_list, skb);
 253         spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
 254 }
 255
 256 /**
 257  * batadv_v_ogm_send_softif() - periodic worker broadcasting the own OGM
 258  * @bat_priv: the bat priv with all the soft interface information
 259  */
 260 static void batadv_v_ogm_send_softif(struct batadv_priv *bat_priv)
 261 {
 262         struct batadv_hard_iface *hard_iface;
 263         struct batadv_ogm2_packet *ogm_packet;
 264         struct sk_buff *skb, *skb_tmp;
 265         unsigned char *ogm_buff;
 266         int ogm_buff_len;
 267         u16 tvlv_len = 0;
 268         int ret;
 269
 270         lockdep_assert_held(&bat_priv->bat_v.ogm_buff_mutex);
 271
 272         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 273                 goto out;
 274
 275         ogm_buff = bat_priv->bat_v.ogm_buff;
 276         ogm_buff_len = bat_priv->bat_v.ogm_buff_len;
 277         /* tt changes have to be committed before the tvlv data is
 278          * appended as it may alter the tt tvlv container
 279          */
 280         batadv_tt_local_commit_changes(bat_priv);
 281         tvlv_len = batadv_tvlv_container_ogm_append(bat_priv, &ogm_buff,
 282                                                     &ogm_buff_len,
 283                                                     BATADV_OGM2_HLEN);
 284
 285         bat_priv->bat_v.ogm_buff = ogm_buff;
 286         bat_priv->bat_v.ogm_buff_len = ogm_buff_len;
 287
 288         skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + ogm_buff_len);
 289         if (!skb)
 290                 goto reschedule;
 291
 292         skb_reserve(skb, ETH_HLEN);
 293         skb_put_data(skb, ogm_buff, ogm_buff_len);
 294
 295         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 296         ogm_packet->seqno = htonl(atomic_read(&bat_priv->bat_v.ogm_seqno));
 297         atomic_inc(&bat_priv->bat_v.ogm_seqno);
 298         ogm_packet->tvlv_len = htons(tvlv_len);
 299
 300         /* broadcast on every interface */
 301         rcu_read_lock();
 302         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 303                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 304                         continue;
 305
 306                 if (!kref_get_unless_zero(&hard_iface->refcount))
 307                         continue;
 308
 309                 ret = batadv_hardif_no_broadcast(hard_iface, NULL, NULL);
 310                 if (ret) {
 311                         char *type;
 312
 313                         switch (ret) {
 314                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 315                                 type = "no neighbor";
 316                                 break;
 317                         case BATADV_HARDIF_BCAST_DUPFWD:
 318                                 type = "single neighbor is source";
 319                                 break;
 320                         case BATADV_HARDIF_BCAST_DUPORIG:
 321                                 type = "single neighbor is originator";
 322                                 break;
 323                         default:
 324                                 type = "unknown";
 325                         }
 326
 327                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 from ourselves on %s suppressed: %s\n",
 328                                    hard_iface->net_dev->name, type);
 329
 330                         batadv_hardif_put(hard_iface);
 331                         continue;
 332                 }
 333
 334                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 335                            "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",
 336                            ogm_packet->orig, ntohl(ogm_packet->seqno),
 337                            ntohl(ogm_packet->throughput), ogm_packet->ttl,
 338                            hard_iface->net_dev->name,
 339                            hard_iface->net_dev->dev_addr);
 340
 341                 /* this skb gets consumed by batadv_v_ogm_send_to_if() */
 342                 skb_tmp = skb_clone(skb, GFP_ATOMIC);
 343                 if (!skb_tmp) {
 344                         batadv_hardif_put(hard_iface);
 345                         break;
 346                 }
 347
 348                 batadv_v_ogm_queue_on_if(skb_tmp, hard_iface);
 349                 batadv_hardif_put(hard_iface);
 350         }
 351         rcu_read_unlock();
 352
 353         consume_skb(skb);
 354
 355 reschedule:
 356         batadv_v_ogm_start_timer(bat_priv);
 357 out:
 358         return;
 359 }
 360
 361 /**
 362  * batadv_v_ogm_send() - periodic worker broadcasting the own OGM
 363  * @work: work queue item
 364  */
 365 static void batadv_v_ogm_send(struct work_struct *work)
 366 {
 367         struct batadv_priv_bat_v *bat_v;
 368         struct batadv_priv *bat_priv;
 369
 370         bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
 371         bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
 372
 373         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 374         batadv_v_ogm_send_softif(bat_priv);
 375         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 376 }
 377
 378 /**
 379  * batadv_v_ogm_aggr_work() - OGM queue periodic task per interface
 380  * @work: work queue item
 381  *
 382  * Emits aggregated OGM messages in regular intervals.
 383  */
 384 void batadv_v_ogm_aggr_work(struct work_struct *work)
 385 {
 386         struct batadv_hard_iface_bat_v *batv;
 387         struct batadv_hard_iface *hard_iface;
 388
 389         batv = container_of(work, struct batadv_hard_iface_bat_v, aggr_wq.work);
 390         hard_iface = container_of(batv, struct batadv_hard_iface, bat_v);
 391
 392         spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
 393         batadv_v_ogm_aggr_send(hard_iface);
 394         spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
 395
 396         batadv_v_ogm_start_queue_timer(hard_iface);
 397 }
 398
 399 /**
 400  * batadv_v_ogm_iface_enable() - prepare an interface for B.A.T.M.A.N. V
 401  * @hard_iface: the interface to prepare
 402  *
 403  * Takes care of scheduling its own OGM sending routine for this interface.
 404  *
 405  * Return: 0 on success or a negative error code otherwise
 406  */
 407 int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 408 {
 409         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 410
 411         batadv_v_ogm_start_queue_timer(hard_iface);
 412         batadv_v_ogm_start_timer(bat_priv);
 413
 414         return 0;
 415 }
 416
 417 /**
 418  * batadv_v_ogm_iface_disable() - release OGM interface private resources
 419  * @hard_iface: interface for which the resources have to be released
 420  */
 421 void batadv_v_ogm_iface_disable(struct batadv_hard_iface *hard_iface)
 422 {
 423         cancel_delayed_work_sync(&hard_iface->bat_v.aggr_wq);
 424
 425         spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
 426         batadv_v_ogm_aggr_list_free(hard_iface);
 427         spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
 428 }
 429
 430 /**
 431  * batadv_v_ogm_primary_iface_set() - set a new primary interface
 432  * @primary_iface: the new primary interface
 433  */
 434 void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
 435 {
 436         struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
 437         struct batadv_ogm2_packet *ogm_packet;
 438
 439         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 440         if (!bat_priv->bat_v.ogm_buff)
 441                 goto unlock;
 442
 443         ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
 444         ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
 445
 446 unlock:
 447         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 448 }
 449
 450 /**
 451  * batadv_v_forward_penalty() - apply a penalty to the throughput metric
 452  *  forwarded with B.A.T.M.A.N. V OGMs
 453  * @bat_priv: the bat priv with all the soft interface information
 454  * @if_incoming: the interface where the OGM has been received
 455  * @if_outgoing: the interface where the OGM has to be forwarded to
 456  * @throughput: the current throughput
 457  *
 458  * Apply a penalty on the current throughput metric value based on the
 459  * characteristic of the interface where the OGM has been received.
 460  *
 461  * Initially the per hardif hop penalty is applied to the throughput. After
 462  * that the return value is then computed as follows:
 463  * - throughput * 50%          if the incoming and outgoing interface are the
 464  *                             same WiFi interface and the throughput is above
 465  *                             1MBit/s
 466  * - throughput                if the outgoing interface is the default
 467  *                             interface (i.e. this OGM is processed for the
 468  *                             internal table and not forwarded)
 469  * - throughput * node hop penalty  otherwise
 470  *
 471  * Return: the penalised throughput metric.
 472  */
 473 static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv,
 474                                     struct batadv_hard_iface *if_incoming,
 475                                     struct batadv_hard_iface *if_outgoing,
 476                                     u32 throughput)
 477 {
 478         int if_hop_penalty = atomic_read(&if_incoming->hop_penalty);
 479         int hop_penalty = atomic_read(&bat_priv->hop_penalty);
 480         int hop_penalty_max = BATADV_TQ_MAX_VALUE;
 481
 482         /* Apply per hardif hop penalty */
 483         throughput = throughput * (hop_penalty_max - if_hop_penalty) /
 484                      hop_penalty_max;
 485
 486         /* Don't apply hop penalty in default originator table. */
 487         if (if_outgoing == BATADV_IF_DEFAULT)
 488                 return throughput;
 489
 490         /* Forwarding on the same WiFi interface cuts the throughput in half
 491          * due to the store & forward characteristics of WIFI.
 492          * Very low throughput values are the exception.
 493          */
 494         if (throughput > 10 &&
 495             if_incoming == if_outgoing &&
 496             !(if_incoming->bat_v.flags & BATADV_FULL_DUPLEX))
 497                 return throughput / 2;
 498
 499         /* hop penalty of 255 equals 100% */
 500         return throughput * (hop_penalty_max - hop_penalty) / hop_penalty_max;
 501 }
 502
 503 /**
 504  * batadv_v_ogm_forward() - check conditions and forward an OGM to the given
 505  *  outgoing interface
 506  * @bat_priv: the bat priv with all the soft interface information
 507  * @ogm_received: previously received OGM to be forwarded
 508  * @orig_node: the originator which has been updated
 509  * @neigh_node: the neigh_node through with the OGM has been received
 510  * @if_incoming: the interface on which this OGM was received on
 511  * @if_outgoing: the interface to which the OGM has to be forwarded to
 512  *
 513  * Forward an OGM to an interface after having altered the throughput metric and
 514  * the TTL value contained in it. The original OGM isn't modified.
 515  */
 516 static void batadv_v_ogm_forward(struct batadv_priv *bat_priv,
 517                                  const struct batadv_ogm2_packet *ogm_received,
 518                                  struct batadv_orig_node *orig_node,
 519                                  struct batadv_neigh_node *neigh_node,
 520                                  struct batadv_hard_iface *if_incoming,
 521                                  struct batadv_hard_iface *if_outgoing)
 522 {
 523         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 524         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 525         struct batadv_neigh_node *router = NULL;
 526         struct batadv_ogm2_packet *ogm_forward;
 527         unsigned char *skb_buff;
 528         struct sk_buff *skb;
 529         size_t packet_len;
 530         u16 tvlv_len;
 531
 532         /* only forward for specific interfaces, not for the default one. */
 533         if (if_outgoing == BATADV_IF_DEFAULT)
 534                 goto out;
 535
 536         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 537         if (!orig_ifinfo)
 538                 goto out;
 539
 540         /* acquire possibly updated router */
 541         router = batadv_orig_router_get(orig_node, if_outgoing);
 542
 543         /* strict rule: forward packets coming from the best next hop only */
 544         if (neigh_node != router)
 545                 goto out;
 546
 547         /* don't forward the same seqno twice on one interface */
 548         if (orig_ifinfo->last_seqno_forwarded == ntohl(ogm_received->seqno))
 549                 goto out;
 550
 551         orig_ifinfo->last_seqno_forwarded = ntohl(ogm_received->seqno);
 552
 553         if (ogm_received->ttl <= 1) {
 554                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
 555                 goto out;
 556         }
 557
 558         neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 559         if (!neigh_ifinfo)
 560                 goto out;
 561
 562         tvlv_len = ntohs(ogm_received->tvlv_len);
 563
 564         packet_len = BATADV_OGM2_HLEN + tvlv_len;
 565         skb = netdev_alloc_skb_ip_align(if_outgoing->net_dev,
 566                                         ETH_HLEN + packet_len);
 567         if (!skb)
 568                 goto out;
 569
 570         skb_reserve(skb, ETH_HLEN);
 571         skb_buff = skb_put_data(skb, ogm_received, packet_len);
 572
 573         /* apply forward penalty */
 574         ogm_forward = (struct batadv_ogm2_packet *)skb_buff;
 575         ogm_forward->throughput = htonl(neigh_ifinfo->bat_v.throughput);
 576         ogm_forward->ttl--;
 577
 578         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 579                    "Forwarding OGM2 packet on %s: throughput %u, ttl %u, received via %s\n",
 580                    if_outgoing->net_dev->name, ntohl(ogm_forward->throughput),
 581                    ogm_forward->ttl, if_incoming->net_dev->name);
 582
 583         batadv_v_ogm_queue_on_if(skb, if_outgoing);
 584
 585 out:
 586         if (orig_ifinfo)
 587                 batadv_orig_ifinfo_put(orig_ifinfo);
 588         if (router)
 589                 batadv_neigh_node_put(router);
 590         if (neigh_ifinfo)
 591                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 592 }
 593
 594 /**
 595  * batadv_v_ogm_metric_update() - update route metric based on OGM
 596  * @bat_priv: the bat priv with all the soft interface information
 597  * @ogm2: OGM2 structure
 598  * @orig_node: Originator structure for which the OGM has been received
 599  * @neigh_node: the neigh_node through with the OGM has been received
 600  * @if_incoming: the interface where this packet was received
 601  * @if_outgoing: the interface for which the packet should be considered
 602  *
 603  * Return:
 604  *  1  if the OGM is new,
 605  *  0  if it is not new but valid,
 606  *  <0 on error (e.g. old OGM)
 607  */
 608 static int batadv_v_ogm_metric_update(struct batadv_priv *bat_priv,
 609                                       const struct batadv_ogm2_packet *ogm2,
 610                                       struct batadv_orig_node *orig_node,
 611                                       struct batadv_neigh_node *neigh_node,
 612                                       struct batadv_hard_iface *if_incoming,
 613                                       struct batadv_hard_iface *if_outgoing)
 614 {
 615         struct batadv_orig_ifinfo *orig_ifinfo;
 616         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 617         bool protection_started = false;
 618         int ret = -EINVAL;
 619         u32 path_throughput;
 620         s32 seq_diff;
 621
 622         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 623         if (!orig_ifinfo)
 624                 goto out;
 625
 626         seq_diff = ntohl(ogm2->seqno) - orig_ifinfo->last_real_seqno;
 627
 628         if (!hlist_empty(&orig_node->neigh_list) &&
 629             batadv_window_protected(bat_priv, seq_diff,
 630                                     BATADV_OGM_MAX_AGE,
 631                                     &orig_ifinfo->batman_seqno_reset,
 632                                     &protection_started)) {
 633                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 634                            "Drop packet: packet within window protection time from %pM\n",
 635                            ogm2->orig);
 636                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 637                            "Last reset: %ld, %ld\n",
 638                            orig_ifinfo->batman_seqno_reset, jiffies);
 639                 goto out;
 640         }
 641
 642         /* drop packets with old seqnos, however accept the first packet after
 643          * a host has been rebooted.
 644          */
 645         if (seq_diff < 0 && !protection_started)
 646                 goto out;
 647
 648         neigh_node->last_seen = jiffies;
 649
 650         orig_node->last_seen = jiffies;
 651
 652         orig_ifinfo->last_real_seqno = ntohl(ogm2->seqno);
 653         orig_ifinfo->last_ttl = ogm2->ttl;
 654
 655         neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
 656         if (!neigh_ifinfo)
 657                 goto out;
 658
 659         path_throughput = batadv_v_forward_penalty(bat_priv, if_incoming,
 660                                                    if_outgoing,
 661                                                    ntohl(ogm2->throughput));
 662         neigh_ifinfo->bat_v.throughput = path_throughput;
 663         neigh_ifinfo->bat_v.last_seqno = ntohl(ogm2->seqno);
 664         neigh_ifinfo->last_ttl = ogm2->ttl;
 665
 666         if (seq_diff > 0 || protection_started)
 667                 ret = 1;
 668         else
 669                 ret = 0;
 670 out:
 671         if (orig_ifinfo)
 672                 batadv_orig_ifinfo_put(orig_ifinfo);
 673         if (neigh_ifinfo)
 674                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 675
 676         return ret;
 677 }
 678
 679 /**
 680  * batadv_v_ogm_route_update() - update routes based on OGM
 681  * @bat_priv: the bat priv with all the soft interface information
 682  * @ethhdr: the Ethernet header of the OGM2
 683  * @ogm2: OGM2 structure
 684  * @orig_node: Originator structure for which the OGM has been received
 685  * @neigh_node: the neigh_node through with the OGM has been received
 686  * @if_incoming: the interface where this packet was received
 687  * @if_outgoing: the interface for which the packet should be considered
 688  *
 689  * Return: true if the packet should be forwarded, false otherwise
 690  */
 691 static bool batadv_v_ogm_route_update(struct batadv_priv *bat_priv,
 692                                       const struct ethhdr *ethhdr,
 693                                       const struct batadv_ogm2_packet *ogm2,
 694                                       struct batadv_orig_node *orig_node,
 695                                       struct batadv_neigh_node *neigh_node,
 696                                       struct batadv_hard_iface *if_incoming,
 697                                       struct batadv_hard_iface *if_outgoing)
 698 {
 699         struct batadv_neigh_node *router = NULL;
 700         struct batadv_orig_node *orig_neigh_node;
 701         struct batadv_neigh_node *orig_neigh_router = NULL;
 702         struct batadv_neigh_ifinfo *router_ifinfo = NULL, *neigh_ifinfo = NULL;
 703         u32 router_throughput, neigh_throughput;
 704         u32 router_last_seqno;
 705         u32 neigh_last_seqno;
 706         s32 neigh_seq_diff;
 707         bool forward = false;
 708
 709         orig_neigh_node = batadv_v_ogm_orig_get(bat_priv, ethhdr->h_source);
 710         if (!orig_neigh_node)
 711                 goto out;
 712
 713         orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
 714                                                    if_outgoing);
 715
 716         /* drop packet if sender is not a direct neighbor and if we
 717          * don't route towards it
 718          */
 719         router = batadv_orig_router_get(orig_node, if_outgoing);
 720         if (router && router->orig_node != orig_node && !orig_neigh_router) {
 721                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 722                            "Drop packet: OGM via unknown neighbor!\n");
 723                 goto out;
 724         }
 725
 726         /* Mark the OGM to be considered for forwarding, and update routes
 727          * if needed.
 728          */
 729         forward = true;
 730
 731         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 732                    "Searching and updating originator entry of received packet\n");
 733
 734         /* if this neighbor already is our next hop there is nothing
 735          * to change
 736          */
 737         if (router == neigh_node)
 738                 goto out;
 739
 740         /* don't consider neighbours with worse throughput.
 741          * also switch route if this seqno is BATADV_V_MAX_ORIGDIFF newer than
 742          * the last received seqno from our best next hop.
 743          */
 744         if (router) {
 745                 router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
 746                 neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 747
 748                 /* if these are not allocated, something is wrong. */
 749                 if (!router_ifinfo || !neigh_ifinfo)
 750                         goto out;
 751
 752                 neigh_last_seqno = neigh_ifinfo->bat_v.last_seqno;
 753                 router_last_seqno = router_ifinfo->bat_v.last_seqno;
 754                 neigh_seq_diff = neigh_last_seqno - router_last_seqno;
 755                 router_throughput = router_ifinfo->bat_v.throughput;
 756                 neigh_throughput = neigh_ifinfo->bat_v.throughput;
 757
 758                 if (neigh_seq_diff < BATADV_OGM_MAX_ORIGDIFF &&
 759                     router_throughput >= neigh_throughput)
 760                         goto out;
 761         }
 762
 763         batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
 764 out:
 765         if (router)
 766                 batadv_neigh_node_put(router);
 767         if (orig_neigh_router)
 768                 batadv_neigh_node_put(orig_neigh_router);
 769         if (orig_neigh_node)
 770                 batadv_orig_node_put(orig_neigh_node);
 771         if (router_ifinfo)
 772                 batadv_neigh_ifinfo_put(router_ifinfo);
 773         if (neigh_ifinfo)
 774                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 775
 776         return forward;
 777 }
 778
 779 /**
 780  * batadv_v_ogm_process_per_outif() - process a batman v OGM for an outgoing if
 781  * @bat_priv: the bat priv with all the soft interface information
 782  * @ethhdr: the Ethernet header of the OGM2
 783  * @ogm2: OGM2 structure
 784  * @orig_node: Originator structure for which the OGM has been received
 785  * @neigh_node: the neigh_node through with the OGM has been received
 786  * @if_incoming: the interface where this packet was received
 787  * @if_outgoing: the interface for which the packet should be considered
 788  */
 789 static void
 790 batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
 791                                const struct ethhdr *ethhdr,
 792                                const struct batadv_ogm2_packet *ogm2,
 793                                struct batadv_orig_node *orig_node,
 794                                struct batadv_neigh_node *neigh_node,
 795                                struct batadv_hard_iface *if_incoming,
 796                                struct batadv_hard_iface *if_outgoing)
 797 {
 798         int seqno_age;
 799         bool forward;
 800
 801         /* first, update the metric with according sanity checks */
 802         seqno_age = batadv_v_ogm_metric_update(bat_priv, ogm2, orig_node,
 803                                                neigh_node, if_incoming,
 804                                                if_outgoing);
 805
 806         /* outdated sequence numbers are to be discarded */
 807         if (seqno_age < 0)
 808                 return;
 809
 810         /* only unknown & newer OGMs contain TVLVs we are interested in */
 811         if (seqno_age > 0 && if_outgoing == BATADV_IF_DEFAULT)
 812                 batadv_tvlv_containers_process(bat_priv, true, orig_node,
 813                                                NULL, NULL,
 814                                                (unsigned char *)(ogm2 + 1),
 815                                                ntohs(ogm2->tvlv_len));
 816
 817         /* if the metric update went through, update routes if needed */
 818         forward = batadv_v_ogm_route_update(bat_priv, ethhdr, ogm2, orig_node,
 819                                             neigh_node, if_incoming,
 820                                             if_outgoing);
 821
 822         /* if the routes have been processed correctly, check and forward */
 823         if (forward)
 824                 batadv_v_ogm_forward(bat_priv, ogm2, orig_node, neigh_node,
 825                                      if_incoming, if_outgoing);
 826 }
 827
 828 /**
 829  * batadv_v_ogm_aggr_packet() - checks if there is another OGM aggregated
 830  * @buff_pos: current position in the skb
 831  * @packet_len: total length of the skb
 832  * @ogm2_packet: potential OGM2 in buffer
 833  *
 834  * Return: true if there is enough space for another OGM, false otherwise.
 835  */
 836 static bool
 837 batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
 838                          const struct batadv_ogm2_packet *ogm2_packet)
 839 {
 840         int next_buff_pos = 0;
 841
 842         /* check if there is enough space for the header */
 843         next_buff_pos += buff_pos + sizeof(*ogm2_packet);
 844         if (next_buff_pos > packet_len)
 845                 return false;
 846
 847         /* check if there is enough space for the optional TVLV */
 848         next_buff_pos += ntohs(ogm2_packet->tvlv_len);
 849
 850         return (next_buff_pos <= packet_len) &&
 851                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
 852 }
 853
 854 /**
 855  * batadv_v_ogm_process() - process an incoming batman v OGM
 856  * @skb: the skb containing the OGM
 857  * @ogm_offset: offset to the OGM which should be processed (for aggregates)
 858  * @if_incoming: the interface where this packet was received
 859  */
 860 static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
 861                                  struct batadv_hard_iface *if_incoming)
 862 {
 863         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 864         struct ethhdr *ethhdr;
 865         struct batadv_orig_node *orig_node = NULL;
 866         struct batadv_hardif_neigh_node *hardif_neigh = NULL;
 867         struct batadv_neigh_node *neigh_node = NULL;
 868         struct batadv_hard_iface *hard_iface;
 869         struct batadv_ogm2_packet *ogm_packet;
 870         u32 ogm_throughput, link_throughput, path_throughput;
 871         int ret;
 872
 873         ethhdr = eth_hdr(skb);
 874         ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
 875
 876         ogm_throughput = ntohl(ogm_packet->throughput);
 877
 878         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 879                    "Received OGM2 packet via NB: %pM, IF: %s [%pM] (from OG: %pM, seqno %u, throughput %u, TTL %u, V %u, tvlv_len %u)\n",
 880                    ethhdr->h_source, if_incoming->net_dev->name,
 881                    if_incoming->net_dev->dev_addr, ogm_packet->orig,
 882                    ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
 883                    ogm_packet->version, ntohs(ogm_packet->tvlv_len));
 884
 885         if (batadv_is_my_mac(bat_priv, ogm_packet->orig)) {
 886                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 887                            "Drop packet: originator packet from ourself\n");
 888                 return;
 889         }
 890
 891         /* If the throughput metric is 0, immediately drop the packet. No need
 892          * to create orig_node / neigh_node for an unusable route.
 893          */
 894         if (ogm_throughput == 0) {
 895                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 896                            "Drop packet: originator packet with throughput metric of 0\n");
 897                 return;
 898         }
 899
 900         /* require ELP packets be to received from this neighbor first */
 901         hardif_neigh = batadv_hardif_neigh_get(if_incoming, ethhdr->h_source);
 902         if (!hardif_neigh) {
 903                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 904                            "Drop packet: OGM via unknown neighbor!\n");
 905                 goto out;
 906         }
 907
 908         orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
 909         if (!orig_node)
 910                 goto out;
 911
 912         neigh_node = batadv_neigh_node_get_or_create(orig_node, if_incoming,
 913                                                      ethhdr->h_source);
 914         if (!neigh_node)
 915                 goto out;
 916
 917         /* Update the received throughput metric to match the link
 918          * characteristic:
 919          *  - If this OGM traveled one hop so far (emitted by single hop
 920          *    neighbor) the path throughput metric equals the link throughput.
 921          *  - For OGMs traversing more than hop the path throughput metric is
 922          *    the smaller of the path throughput and the link throughput.
 923          */
 924         link_throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
 925         path_throughput = min_t(u32, link_throughput, ogm_throughput);
 926         ogm_packet->throughput = htonl(path_throughput);
 927
 928         batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet, orig_node,
 929                                        neigh_node, if_incoming,
 930                                        BATADV_IF_DEFAULT);
 931
 932         rcu_read_lock();
 933         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 934                 if (hard_iface->if_status != BATADV_IF_ACTIVE)
 935                         continue;
 936
 937                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 938                         continue;
 939
 940                 if (!kref_get_unless_zero(&hard_iface->refcount))
 941                         continue;
 942
 943                 ret = batadv_hardif_no_broadcast(hard_iface,
 944                                                  ogm_packet->orig,
 945                                                  hardif_neigh->orig);
 946
 947                 if (ret) {
 948                         char *type;
 949
 950                         switch (ret) {
 951                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 952                                 type = "no neighbor";
 953                                 break;
 954                         case BATADV_HARDIF_BCAST_DUPFWD:
 955                                 type = "single neighbor is source";
 956                                 break;
 957                         case BATADV_HARDIF_BCAST_DUPORIG:
 958                                 type = "single neighbor is originator";
 959                                 break;
 960                         default:
 961                                 type = "unknown";
 962                         }
 963
 964                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 packet from %pM on %s suppressed: %s\n",
 965                                    ogm_packet->orig, hard_iface->net_dev->name,
 966                                    type);
 967
 968                         batadv_hardif_put(hard_iface);
 969                         continue;
 970                 }
 971
 972                 batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,
 973                                                orig_node, neigh_node,
 974                                                if_incoming, hard_iface);
 975
 976                 batadv_hardif_put(hard_iface);
 977         }
 978         rcu_read_unlock();
 979 out:
 980         if (orig_node)
 981                 batadv_orig_node_put(orig_node);
 982         if (neigh_node)
 983                 batadv_neigh_node_put(neigh_node);
 984         if (hardif_neigh)
 985                 batadv_hardif_neigh_put(hardif_neigh);
 986 }
 987
 988 /**
 989  * batadv_v_ogm_packet_recv() - OGM2 receiving handler
 990  * @skb: the received OGM
 991  * @if_incoming: the interface where this OGM has been received
 992  *
 993  * Return: NET_RX_SUCCESS and consume the skb on success or returns NET_RX_DROP
 994  * (without freeing the skb) on failure
 995  */
 996 int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 997                              struct batadv_hard_iface *if_incoming)
 998 {
 999         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
1000         struct batadv_ogm2_packet *ogm_packet;
1001         struct ethhdr *ethhdr = eth_hdr(skb);
1002         int ogm_offset;
1003         u8 *packet_pos;
1004         int ret = NET_RX_DROP;
1005
1006         /* did we receive a OGM2 packet on an interface that does not have
1007          * B.A.T.M.A.N. V enabled ?
1008          */
1009         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
1010                 goto free_skb;
1011
1012         if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
1013                 goto free_skb;
1014
1015         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1016                 goto free_skb;
1017
1018         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
1019         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
1020                            skb->len + ETH_HLEN);
1021
1022         ogm_offset = 0;
1023         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
1024
1025         while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
1026                                         ogm_packet)) {
1027                 batadv_v_ogm_process(skb, ogm_offset, if_incoming);
1028
1029                 ogm_offset += BATADV_OGM2_HLEN;
1030                 ogm_offset += ntohs(ogm_packet->tvlv_len);
1031
1032                 packet_pos = skb->data + ogm_offset;
1033                 ogm_packet = (struct batadv_ogm2_packet *)packet_pos;
1034         }
1035
1036         ret = NET_RX_SUCCESS;
1037
1038 free_skb:
1039         if (ret == NET_RX_SUCCESS)
1040                 consume_skb(skb);
1041         else
1042                 kfree_skb(skb);
1043
1044         return ret;
1045 }
1046
1047 /**
1048  * batadv_v_ogm_init() - initialise the OGM2 engine
1049  * @bat_priv: the bat priv with all the soft interface information
1050  *
1051  * Return: 0 on success or a negative error code in case of failure
1052  */
1053 int batadv_v_ogm_init(struct batadv_priv *bat_priv)
1054 {
1055         struct batadv_ogm2_packet *ogm_packet;
1056         unsigned char *ogm_buff;
1057         u32 random_seqno;
1058
1059         bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
1060         ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
1061         if (!ogm_buff)
1062                 return -ENOMEM;
1063
1064         bat_priv->bat_v.ogm_buff = ogm_buff;
1065         ogm_packet = (struct batadv_ogm2_packet *)ogm_buff;
1066         ogm_packet->packet_type = BATADV_OGM2;
1067         ogm_packet->version = BATADV_COMPAT_VERSION;
1068         ogm_packet->ttl = BATADV_TTL;
1069         ogm_packet->flags = BATADV_NO_FLAGS;
1070         ogm_packet->throughput = htonl(BATADV_THROUGHPUT_MAX_VALUE);
1071
1072         /* randomize initial seqno to avoid collision */
1073         get_random_bytes(&random_seqno, sizeof(random_seqno));
1074         atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
1075         INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
1076
1077         mutex_init(&bat_priv->bat_v.ogm_buff_mutex);
1078
1079         return 0;
1080 }
1081
1082 /**
1083  * batadv_v_ogm_free() - free OGM private resources
1084  * @bat_priv: the bat priv with all the soft interface information
1085  */
1086 void batadv_v_ogm_free(struct batadv_priv *bat_priv)
1087 {
1088         cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
1089
1090         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
1091
1092         kfree(bat_priv->bat_v.ogm_buff);
1093         bat_priv->bat_v.ogm_buff = NULL;
1094         bat_priv->bat_v.ogm_buff_len = 0;
1095
1096         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
1097 }