net/batman-adv/bat_v_ogm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 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/minmax.h>
  22 #include <linux/mutex.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/prandom.h>
  25 #include <linux/random.h>
  26 #include <linux/rculist.h>
  27 #include <linux/rcupdate.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/slab.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/stddef.h>
  32 #include <linux/string.h>
  33 #include <linux/types.h>
  34 #include <linux/workqueue.h>
  35 #include <uapi/linux/batadv_packet.h>
  36
  37 #include "bat_algo.h"
  38 #include "hard-interface.h"
  39 #include "hash.h"
  40 #include "log.h"
  41 #include "originator.h"
  42 #include "routing.h"
  43 #include "send.h"
  44 #include "translation-table.h"
  45 #include "tvlv.h"
  46
  47 /**
  48  * batadv_v_ogm_orig_get() - retrieve and possibly create an originator node
  49  * @bat_priv: the bat priv with all the soft interface information
  50  * @addr: the address of the originator
  51  *
  52  * Return: the orig_node corresponding to the specified address. If such an
  53  * object does not exist, it is allocated here. In case of allocation failure
  54  * returns NULL.
  55  */
  56 struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv,
  57                                                const u8 *addr)
  58 {
  59         struct batadv_orig_node *orig_node;
  60         int hash_added;
  61
  62         orig_node = batadv_orig_hash_find(bat_priv, addr);
  63         if (orig_node)
  64                 return orig_node;
  65
  66         orig_node = batadv_orig_node_new(bat_priv, addr);
  67         if (!orig_node)
  68                 return NULL;
  69
  70         kref_get(&orig_node->refcount);
  71         hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
  72                                      batadv_choose_orig, orig_node,
  73                                      &orig_node->hash_entry);
  74         if (hash_added != 0) {
  75                 /* remove refcnt for newly created orig_node and hash entry */
  76                 batadv_orig_node_put(orig_node);
  77                 batadv_orig_node_put(orig_node);
  78                 orig_node = NULL;
  79         }
  80
  81         return orig_node;
  82 }
  83
  84 /**
  85  * batadv_v_ogm_start_queue_timer() - restart the OGM aggregation timer
  86  * @hard_iface: the interface to use to send the OGM
  87  */
  88 static void batadv_v_ogm_start_queue_timer(struct batadv_hard_iface *hard_iface)
  89 {
  90         unsigned int msecs = BATADV_MAX_AGGREGATION_MS * 1000;
  91
  92         /* msecs * [0.9, 1.1] */
  93         msecs += prandom_u32_max(msecs / 5) - (msecs / 10);
  94         queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.aggr_wq,
  95                            msecs_to_jiffies(msecs / 1000));
  96 }
  97
  98 /**
  99  * batadv_v_ogm_start_timer() - restart the OGM sending timer
 100  * @bat_priv: the bat priv with all the soft interface information
 101  */
 102 static void batadv_v_ogm_start_timer(struct batadv_priv *bat_priv)
 103 {
 104         unsigned long msecs;
 105         /* this function may be invoked in different contexts (ogm rescheduling
 106          * or hard_iface activation), but the work timer should not be reset
 107          */
 108         if (delayed_work_pending(&bat_priv->bat_v.ogm_wq))
 109                 return;
 110
 111         msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER;
 112         msecs += prandom_u32_max(2 * BATADV_JITTER);
 113         queue_delayed_work(batadv_event_workqueue, &bat_priv->bat_v.ogm_wq,
 114                            msecs_to_jiffies(msecs));
 115 }
 116
 117 /**
 118  * batadv_v_ogm_send_to_if() - send a batman ogm using a given interface
 119  * @skb: the OGM to send
 120  * @hard_iface: the interface to use to send the OGM
 121  */
 122 static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
 123                                     struct batadv_hard_iface *hard_iface)
 124 {
 125         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 126
 127         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 128                 return;
 129
 130         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
 131         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
 132                            skb->len + ETH_HLEN);
 133
 134         batadv_send_broadcast_skb(skb, hard_iface);
 135 }
 136
 137 /**
 138  * batadv_v_ogm_len() - OGMv2 packet length
 139  * @skb: the OGM to check
 140  *
 141  * Return: Length of the given OGMv2 packet, including tvlv length, excluding
 142  * ethernet header length.
 143  */
 144 static unsigned int batadv_v_ogm_len(struct sk_buff *skb)
 145 {
 146         struct batadv_ogm2_packet *ogm_packet;
 147
 148         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 149         return BATADV_OGM2_HLEN + ntohs(ogm_packet->tvlv_len);
 150 }
 151
 152 /**
 153  * batadv_v_ogm_queue_left() - check if given OGM still fits aggregation queue
 154  * @skb: the OGM to check
 155  * @hard_iface: the interface to use to send the OGM
 156  *
 157  * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
 158  *
 159  * Return: True, if the given OGMv2 packet still fits, false otherwise.
 160  */
 161 static bool batadv_v_ogm_queue_left(struct sk_buff *skb,
 162                                     struct batadv_hard_iface *hard_iface)
 163 {
 164         unsigned int max = min_t(unsigned int, hard_iface->net_dev->mtu,
 165                                  BATADV_MAX_AGGREGATION_BYTES);
 166         unsigned int ogm_len = batadv_v_ogm_len(skb);
 167
 168         lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);
 169
 170         return hard_iface->bat_v.aggr_len + ogm_len <= max;
 171 }
 172
 173 /**
 174  * batadv_v_ogm_aggr_list_free - free all elements in an aggregation queue
 175  * @hard_iface: the interface holding the aggregation queue
 176  *
 177  * Empties the OGMv2 aggregation queue and frees all the skbs it contains.
 178  *
 179  * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
 180  */
 181 static void batadv_v_ogm_aggr_list_free(struct batadv_hard_iface *hard_iface)
 182 {
 183         lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);
 184
 185         __skb_queue_purge(&hard_iface->bat_v.aggr_list);
 186         hard_iface->bat_v.aggr_len = 0;
 187 }
 188
 189 /**
 190  * batadv_v_ogm_aggr_send() - flush & send aggregation queue
 191  * @hard_iface: the interface with the aggregation queue to flush
 192  *
 193  * Aggregates all OGMv2 packets currently in the aggregation queue into a
 194  * single OGMv2 packet and transmits this aggregate.
 195  *
 196  * The aggregation queue is empty after this call.
 197  *
 198  * Caller needs to hold the hard_iface->bat_v.aggr_list.lock.
 199  */
 200 static void batadv_v_ogm_aggr_send(struct batadv_hard_iface *hard_iface)
 201 {
 202         unsigned int aggr_len = hard_iface->bat_v.aggr_len;
 203         struct sk_buff *skb_aggr;
 204         unsigned int ogm_len;
 205         struct sk_buff *skb;
 206
 207         lockdep_assert_held(&hard_iface->bat_v.aggr_list.lock);
 208
 209         if (!aggr_len)
 210                 return;
 211
 212         skb_aggr = dev_alloc_skb(aggr_len + ETH_HLEN + NET_IP_ALIGN);
 213         if (!skb_aggr) {
 214                 batadv_v_ogm_aggr_list_free(hard_iface);
 215                 return;
 216         }
 217
 218         skb_reserve(skb_aggr, ETH_HLEN + NET_IP_ALIGN);
 219         skb_reset_network_header(skb_aggr);
 220
 221         while ((skb = __skb_dequeue(&hard_iface->bat_v.aggr_list))) {
 222                 hard_iface->bat_v.aggr_len -= batadv_v_ogm_len(skb);
 223
 224                 ogm_len = batadv_v_ogm_len(skb);
 225                 skb_put_data(skb_aggr, skb->data, ogm_len);
 226
 227                 consume_skb(skb);
 228         }
 229
 230         batadv_v_ogm_send_to_if(skb_aggr, hard_iface);
 231 }
 232
 233 /**
 234  * batadv_v_ogm_queue_on_if() - queue a batman ogm on a given interface
 235  * @skb: the OGM to queue
 236  * @hard_iface: the interface to queue the OGM on
 237  */
 238 static void batadv_v_ogm_queue_on_if(struct sk_buff *skb,
 239                                      struct batadv_hard_iface *hard_iface)
 240 {
 241         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 242
 243         if (!atomic_read(&bat_priv->aggregated_ogms)) {
 244                 batadv_v_ogm_send_to_if(skb, hard_iface);
 245                 return;
 246         }
 247
 248         spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
 249         if (!batadv_v_ogm_queue_left(skb, hard_iface))
 250                 batadv_v_ogm_aggr_send(hard_iface);
 251
 252         hard_iface->bat_v.aggr_len += batadv_v_ogm_len(skb);
 253         __skb_queue_tail(&hard_iface->bat_v.aggr_list, skb);
 254         spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
 255 }
 256
 257 /**
 258  * batadv_v_ogm_send_softif() - periodic worker broadcasting the own OGM
 259  * @bat_priv: the bat priv with all the soft interface information
 260  */
 261 static void batadv_v_ogm_send_softif(struct batadv_priv *bat_priv)
 262 {
 263         struct batadv_hard_iface *hard_iface;
 264         struct batadv_ogm2_packet *ogm_packet;
 265         struct sk_buff *skb, *skb_tmp;
 266         unsigned char *ogm_buff;
 267         int ogm_buff_len;
 268         u16 tvlv_len = 0;
 269         int ret;
 270
 271         lockdep_assert_held(&bat_priv->bat_v.ogm_buff_mutex);
 272
 273         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 274                 goto out;
 275
 276         ogm_buff = bat_priv->bat_v.ogm_buff;
 277         ogm_buff_len = bat_priv->bat_v.ogm_buff_len;
 278         /* tt changes have to be committed before the tvlv data is
 279          * appended as it may alter the tt tvlv container
 280          */
 281         batadv_tt_local_commit_changes(bat_priv);
 282         tvlv_len = batadv_tvlv_container_ogm_append(bat_priv, &ogm_buff,
 283                                                     &ogm_buff_len,
 284                                                     BATADV_OGM2_HLEN);
 285
 286         bat_priv->bat_v.ogm_buff = ogm_buff;
 287         bat_priv->bat_v.ogm_buff_len = ogm_buff_len;
 288
 289         skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + ogm_buff_len);
 290         if (!skb)
 291                 goto reschedule;
 292
 293         skb_reserve(skb, ETH_HLEN);
 294         skb_put_data(skb, ogm_buff, ogm_buff_len);
 295
 296         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 297         ogm_packet->seqno = htonl(atomic_read(&bat_priv->bat_v.ogm_seqno));
 298         atomic_inc(&bat_priv->bat_v.ogm_seqno);
 299         ogm_packet->tvlv_len = htons(tvlv_len);
 300
 301         /* broadcast on every interface */
 302         rcu_read_lock();
 303         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 304                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 305                         continue;
 306
 307                 if (!kref_get_unless_zero(&hard_iface->refcount))
 308                         continue;
 309
 310                 ret = batadv_hardif_no_broadcast(hard_iface, NULL, NULL);
 311                 if (ret) {
 312                         char *type;
 313
 314                         switch (ret) {
 315                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 316                                 type = "no neighbor";
 317                                 break;
 318                         case BATADV_HARDIF_BCAST_DUPFWD:
 319                                 type = "single neighbor is source";
 320                                 break;
 321                         case BATADV_HARDIF_BCAST_DUPORIG:
 322                                 type = "single neighbor is originator";
 323                                 break;
 324                         default:
 325                                 type = "unknown";
 326                         }
 327
 328                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 from ourselves on %s suppressed: %s\n",
 329                                    hard_iface->net_dev->name, type);
 330
 331                         batadv_hardif_put(hard_iface);
 332                         continue;
 333                 }
 334
 335                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 336                            "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",
 337                            ogm_packet->orig, ntohl(ogm_packet->seqno),
 338                            ntohl(ogm_packet->throughput), ogm_packet->ttl,
 339                            hard_iface->net_dev->name,
 340                            hard_iface->net_dev->dev_addr);
 341
 342                 /* this skb gets consumed by batadv_v_ogm_send_to_if() */
 343                 skb_tmp = skb_clone(skb, GFP_ATOMIC);
 344                 if (!skb_tmp) {
 345                         batadv_hardif_put(hard_iface);
 346                         break;
 347                 }
 348
 349                 batadv_v_ogm_queue_on_if(skb_tmp, hard_iface);
 350                 batadv_hardif_put(hard_iface);
 351         }
 352         rcu_read_unlock();
 353
 354         consume_skb(skb);
 355
 356 reschedule:
 357         batadv_v_ogm_start_timer(bat_priv);
 358 out:
 359         return;
 360 }
 361
 362 /**
 363  * batadv_v_ogm_send() - periodic worker broadcasting the own OGM
 364  * @work: work queue item
 365  */
 366 static void batadv_v_ogm_send(struct work_struct *work)
 367 {
 368         struct batadv_priv_bat_v *bat_v;
 369         struct batadv_priv *bat_priv;
 370
 371         bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
 372         bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
 373
 374         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 375         batadv_v_ogm_send_softif(bat_priv);
 376         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 377 }
 378
 379 /**
 380  * batadv_v_ogm_aggr_work() - OGM queue periodic task per interface
 381  * @work: work queue item
 382  *
 383  * Emits aggregated OGM messages in regular intervals.
 384  */
 385 void batadv_v_ogm_aggr_work(struct work_struct *work)
 386 {
 387         struct batadv_hard_iface_bat_v *batv;
 388         struct batadv_hard_iface *hard_iface;
 389
 390         batv = container_of(work, struct batadv_hard_iface_bat_v, aggr_wq.work);
 391         hard_iface = container_of(batv, struct batadv_hard_iface, bat_v);
 392
 393         spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
 394         batadv_v_ogm_aggr_send(hard_iface);
 395         spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
 396
 397         batadv_v_ogm_start_queue_timer(hard_iface);
 398 }
 399
 400 /**
 401  * batadv_v_ogm_iface_enable() - prepare an interface for B.A.T.M.A.N. V
 402  * @hard_iface: the interface to prepare
 403  *
 404  * Takes care of scheduling its own OGM sending routine for this interface.
 405  *
 406  * Return: 0 on success or a negative error code otherwise
 407  */
 408 int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 409 {
 410         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 411
 412         batadv_v_ogm_start_queue_timer(hard_iface);
 413         batadv_v_ogm_start_timer(bat_priv);
 414
 415         return 0;
 416 }
 417
 418 /**
 419  * batadv_v_ogm_iface_disable() - release OGM interface private resources
 420  * @hard_iface: interface for which the resources have to be released
 421  */
 422 void batadv_v_ogm_iface_disable(struct batadv_hard_iface *hard_iface)
 423 {
 424         cancel_delayed_work_sync(&hard_iface->bat_v.aggr_wq);
 425
 426         spin_lock_bh(&hard_iface->bat_v.aggr_list.lock);
 427         batadv_v_ogm_aggr_list_free(hard_iface);
 428         spin_unlock_bh(&hard_iface->bat_v.aggr_list.lock);
 429 }
 430
 431 /**
 432  * batadv_v_ogm_primary_iface_set() - set a new primary interface
 433  * @primary_iface: the new primary interface
 434  */
 435 void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
 436 {
 437         struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
 438         struct batadv_ogm2_packet *ogm_packet;
 439
 440         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 441         if (!bat_priv->bat_v.ogm_buff)
 442                 goto unlock;
 443
 444         ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
 445         ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
 446
 447 unlock:
 448         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 449 }
 450
 451 /**
 452  * batadv_v_forward_penalty() - apply a penalty to the throughput metric
 453  *  forwarded with B.A.T.M.A.N. V OGMs
 454  * @bat_priv: the bat priv with all the soft interface information
 455  * @if_incoming: the interface where the OGM has been received
 456  * @if_outgoing: the interface where the OGM has to be forwarded to
 457  * @throughput: the current throughput
 458  *
 459  * Apply a penalty on the current throughput metric value based on the
 460  * characteristic of the interface where the OGM has been received.
 461  *
 462  * Initially the per hardif hop penalty is applied to the throughput. After
 463  * that the return value is then computed as follows:
 464  * - throughput * 50%          if the incoming and outgoing interface are the
 465  *                             same WiFi interface and the throughput is above
 466  *                             1MBit/s
 467  * - throughput                if the outgoing interface is the default
 468  *                             interface (i.e. this OGM is processed for the
 469  *                             internal table and not forwarded)
 470  * - throughput * node hop penalty  otherwise
 471  *
 472  * Return: the penalised throughput metric.
 473  */
 474 static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv,
 475                                     struct batadv_hard_iface *if_incoming,
 476                                     struct batadv_hard_iface *if_outgoing,
 477                                     u32 throughput)
 478 {
 479         int if_hop_penalty = atomic_read(&if_incoming->hop_penalty);
 480         int hop_penalty = atomic_read(&bat_priv->hop_penalty);
 481         int hop_penalty_max = BATADV_TQ_MAX_VALUE;
 482
 483         /* Apply per hardif hop penalty */
 484         throughput = throughput * (hop_penalty_max - if_hop_penalty) /
 485                      hop_penalty_max;
 486
 487         /* Don't apply hop penalty in default originator table. */
 488         if (if_outgoing == BATADV_IF_DEFAULT)
 489                 return throughput;
 490
 491         /* Forwarding on the same WiFi interface cuts the throughput in half
 492          * due to the store & forward characteristics of WIFI.
 493          * Very low throughput values are the exception.
 494          */
 495         if (throughput > 10 &&
 496             if_incoming == if_outgoing &&
 497             !(if_incoming->bat_v.flags & BATADV_FULL_DUPLEX))
 498                 return throughput / 2;
 499
 500         /* hop penalty of 255 equals 100% */
 501         return throughput * (hop_penalty_max - hop_penalty) / hop_penalty_max;
 502 }
 503
 504 /**
 505  * batadv_v_ogm_forward() - check conditions and forward an OGM to the given
 506  *  outgoing interface
 507  * @bat_priv: the bat priv with all the soft interface information
 508  * @ogm_received: previously received OGM to be forwarded
 509  * @orig_node: the originator which has been updated
 510  * @neigh_node: the neigh_node through with the OGM has been received
 511  * @if_incoming: the interface on which this OGM was received on
 512  * @if_outgoing: the interface to which the OGM has to be forwarded to
 513  *
 514  * Forward an OGM to an interface after having altered the throughput metric and
 515  * the TTL value contained in it. The original OGM isn't modified.
 516  */
 517 static void batadv_v_ogm_forward(struct batadv_priv *bat_priv,
 518                                  const struct batadv_ogm2_packet *ogm_received,
 519                                  struct batadv_orig_node *orig_node,
 520                                  struct batadv_neigh_node *neigh_node,
 521                                  struct batadv_hard_iface *if_incoming,
 522                                  struct batadv_hard_iface *if_outgoing)
 523 {
 524         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 525         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 526         struct batadv_neigh_node *router = NULL;
 527         struct batadv_ogm2_packet *ogm_forward;
 528         unsigned char *skb_buff;
 529         struct sk_buff *skb;
 530         size_t packet_len;
 531         u16 tvlv_len;
 532
 533         /* only forward for specific interfaces, not for the default one. */
 534         if (if_outgoing == BATADV_IF_DEFAULT)
 535                 goto out;
 536
 537         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 538         if (!orig_ifinfo)
 539                 goto out;
 540
 541         /* acquire possibly updated router */
 542         router = batadv_orig_router_get(orig_node, if_outgoing);
 543
 544         /* strict rule: forward packets coming from the best next hop only */
 545         if (neigh_node != router)
 546                 goto out;
 547
 548         /* don't forward the same seqno twice on one interface */
 549         if (orig_ifinfo->last_seqno_forwarded == ntohl(ogm_received->seqno))
 550                 goto out;
 551
 552         orig_ifinfo->last_seqno_forwarded = ntohl(ogm_received->seqno);
 553
 554         if (ogm_received->ttl <= 1) {
 555                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
 556                 goto out;
 557         }
 558
 559         neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 560         if (!neigh_ifinfo)
 561                 goto out;
 562
 563         tvlv_len = ntohs(ogm_received->tvlv_len);
 564
 565         packet_len = BATADV_OGM2_HLEN + tvlv_len;
 566         skb = netdev_alloc_skb_ip_align(if_outgoing->net_dev,
 567                                         ETH_HLEN + packet_len);
 568         if (!skb)
 569                 goto out;
 570
 571         skb_reserve(skb, ETH_HLEN);
 572         skb_buff = skb_put_data(skb, ogm_received, packet_len);
 573
 574         /* apply forward penalty */
 575         ogm_forward = (struct batadv_ogm2_packet *)skb_buff;
 576         ogm_forward->throughput = htonl(neigh_ifinfo->bat_v.throughput);
 577         ogm_forward->ttl--;
 578
 579         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 580                    "Forwarding OGM2 packet on %s: throughput %u, ttl %u, received via %s\n",
 581                    if_outgoing->net_dev->name, ntohl(ogm_forward->throughput),
 582                    ogm_forward->ttl, if_incoming->net_dev->name);
 583
 584         batadv_v_ogm_queue_on_if(skb, if_outgoing);
 585
 586 out:
 587         if (orig_ifinfo)
 588                 batadv_orig_ifinfo_put(orig_ifinfo);
 589         if (router)
 590                 batadv_neigh_node_put(router);
 591         if (neigh_ifinfo)
 592                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 593 }
 594
 595 /**
 596  * batadv_v_ogm_metric_update() - update route metric based on OGM
 597  * @bat_priv: the bat priv with all the soft interface information
 598  * @ogm2: OGM2 structure
 599  * @orig_node: Originator structure for which the OGM has been received
 600  * @neigh_node: the neigh_node through with the OGM has been received
 601  * @if_incoming: the interface where this packet was received
 602  * @if_outgoing: the interface for which the packet should be considered
 603  *
 604  * Return:
 605  *  1  if the OGM is new,
 606  *  0  if it is not new but valid,
 607  *  <0 on error (e.g. old OGM)
 608  */
 609 static int batadv_v_ogm_metric_update(struct batadv_priv *bat_priv,
 610                                       const struct batadv_ogm2_packet *ogm2,
 611                                       struct batadv_orig_node *orig_node,
 612                                       struct batadv_neigh_node *neigh_node,
 613                                       struct batadv_hard_iface *if_incoming,
 614                                       struct batadv_hard_iface *if_outgoing)
 615 {
 616         struct batadv_orig_ifinfo *orig_ifinfo;
 617         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 618         bool protection_started = false;
 619         int ret = -EINVAL;
 620         u32 path_throughput;
 621         s32 seq_diff;
 622
 623         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 624         if (!orig_ifinfo)
 625                 goto out;
 626
 627         seq_diff = ntohl(ogm2->seqno) - orig_ifinfo->last_real_seqno;
 628
 629         if (!hlist_empty(&orig_node->neigh_list) &&
 630             batadv_window_protected(bat_priv, seq_diff,
 631                                     BATADV_OGM_MAX_AGE,
 632                                     &orig_ifinfo->batman_seqno_reset,
 633                                     &protection_started)) {
 634                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 635                            "Drop packet: packet within window protection time from %pM\n",
 636                            ogm2->orig);
 637                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 638                            "Last reset: %ld, %ld\n",
 639                            orig_ifinfo->batman_seqno_reset, jiffies);
 640                 goto out;
 641         }
 642
 643         /* drop packets with old seqnos, however accept the first packet after
 644          * a host has been rebooted.
 645          */
 646         if (seq_diff < 0 && !protection_started)
 647                 goto out;
 648
 649         neigh_node->last_seen = jiffies;
 650
 651         orig_node->last_seen = jiffies;
 652
 653         orig_ifinfo->last_real_seqno = ntohl(ogm2->seqno);
 654         orig_ifinfo->last_ttl = ogm2->ttl;
 655
 656         neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
 657         if (!neigh_ifinfo)
 658                 goto out;
 659
 660         path_throughput = batadv_v_forward_penalty(bat_priv, if_incoming,
 661                                                    if_outgoing,
 662                                                    ntohl(ogm2->throughput));
 663         neigh_ifinfo->bat_v.throughput = path_throughput;
 664         neigh_ifinfo->bat_v.last_seqno = ntohl(ogm2->seqno);
 665         neigh_ifinfo->last_ttl = ogm2->ttl;
 666
 667         if (seq_diff > 0 || protection_started)
 668                 ret = 1;
 669         else
 670                 ret = 0;
 671 out:
 672         if (orig_ifinfo)
 673                 batadv_orig_ifinfo_put(orig_ifinfo);
 674         if (neigh_ifinfo)
 675                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 676
 677         return ret;
 678 }
 679
 680 /**
 681  * batadv_v_ogm_route_update() - update routes based on OGM
 682  * @bat_priv: the bat priv with all the soft interface information
 683  * @ethhdr: the Ethernet header of the OGM2
 684  * @ogm2: OGM2 structure
 685  * @orig_node: Originator structure for which the OGM has been received
 686  * @neigh_node: the neigh_node through with the OGM has been received
 687  * @if_incoming: the interface where this packet was received
 688  * @if_outgoing: the interface for which the packet should be considered
 689  *
 690  * Return: true if the packet should be forwarded, false otherwise
 691  */
 692 static bool batadv_v_ogm_route_update(struct batadv_priv *bat_priv,
 693                                       const struct ethhdr *ethhdr,
 694                                       const struct batadv_ogm2_packet *ogm2,
 695                                       struct batadv_orig_node *orig_node,
 696                                       struct batadv_neigh_node *neigh_node,
 697                                       struct batadv_hard_iface *if_incoming,
 698                                       struct batadv_hard_iface *if_outgoing)
 699 {
 700         struct batadv_neigh_node *router = NULL;
 701         struct batadv_orig_node *orig_neigh_node;
 702         struct batadv_neigh_node *orig_neigh_router = NULL;
 703         struct batadv_neigh_ifinfo *router_ifinfo = NULL, *neigh_ifinfo = NULL;
 704         u32 router_throughput, neigh_throughput;
 705         u32 router_last_seqno;
 706         u32 neigh_last_seqno;
 707         s32 neigh_seq_diff;
 708         bool forward = false;
 709
 710         orig_neigh_node = batadv_v_ogm_orig_get(bat_priv, ethhdr->h_source);
 711         if (!orig_neigh_node)
 712                 goto out;
 713
 714         orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
 715                                                    if_outgoing);
 716
 717         /* drop packet if sender is not a direct neighbor and if we
 718          * don't route towards it
 719          */
 720         router = batadv_orig_router_get(orig_node, if_outgoing);
 721         if (router && router->orig_node != orig_node && !orig_neigh_router) {
 722                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 723                            "Drop packet: OGM via unknown neighbor!\n");
 724                 goto out;
 725         }
 726
 727         /* Mark the OGM to be considered for forwarding, and update routes
 728          * if needed.
 729          */
 730         forward = true;
 731
 732         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 733                    "Searching and updating originator entry of received packet\n");
 734
 735         /* if this neighbor already is our next hop there is nothing
 736          * to change
 737          */
 738         if (router == neigh_node)
 739                 goto out;
 740
 741         /* don't consider neighbours with worse throughput.
 742          * also switch route if this seqno is BATADV_V_MAX_ORIGDIFF newer than
 743          * the last received seqno from our best next hop.
 744          */
 745         if (router) {
 746                 router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
 747                 neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 748
 749                 /* if these are not allocated, something is wrong. */
 750                 if (!router_ifinfo || !neigh_ifinfo)
 751                         goto out;
 752
 753                 neigh_last_seqno = neigh_ifinfo->bat_v.last_seqno;
 754                 router_last_seqno = router_ifinfo->bat_v.last_seqno;
 755                 neigh_seq_diff = neigh_last_seqno - router_last_seqno;
 756                 router_throughput = router_ifinfo->bat_v.throughput;
 757                 neigh_throughput = neigh_ifinfo->bat_v.throughput;
 758
 759                 if (neigh_seq_diff < BATADV_OGM_MAX_ORIGDIFF &&
 760                     router_throughput >= neigh_throughput)
 761                         goto out;
 762         }
 763
 764         batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
 765 out:
 766         if (router)
 767                 batadv_neigh_node_put(router);
 768         if (orig_neigh_router)
 769                 batadv_neigh_node_put(orig_neigh_router);
 770         if (orig_neigh_node)
 771                 batadv_orig_node_put(orig_neigh_node);
 772         if (router_ifinfo)
 773                 batadv_neigh_ifinfo_put(router_ifinfo);
 774         if (neigh_ifinfo)
 775                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 776
 777         return forward;
 778 }
 779
 780 /**
 781  * batadv_v_ogm_process_per_outif() - process a batman v OGM for an outgoing if
 782  * @bat_priv: the bat priv with all the soft interface information
 783  * @ethhdr: the Ethernet header of the OGM2
 784  * @ogm2: OGM2 structure
 785  * @orig_node: Originator structure for which the OGM has been received
 786  * @neigh_node: the neigh_node through with the OGM has been received
 787  * @if_incoming: the interface where this packet was received
 788  * @if_outgoing: the interface for which the packet should be considered
 789  */
 790 static void
 791 batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
 792                                const struct ethhdr *ethhdr,
 793                                const struct batadv_ogm2_packet *ogm2,
 794                                struct batadv_orig_node *orig_node,
 795                                struct batadv_neigh_node *neigh_node,
 796                                struct batadv_hard_iface *if_incoming,
 797                                struct batadv_hard_iface *if_outgoing)
 798 {
 799         int seqno_age;
 800         bool forward;
 801
 802         /* first, update the metric with according sanity checks */
 803         seqno_age = batadv_v_ogm_metric_update(bat_priv, ogm2, orig_node,
 804                                                neigh_node, if_incoming,
 805                                                if_outgoing);
 806
 807         /* outdated sequence numbers are to be discarded */
 808         if (seqno_age < 0)
 809                 return;
 810
 811         /* only unknown & newer OGMs contain TVLVs we are interested in */
 812         if (seqno_age > 0 && if_outgoing == BATADV_IF_DEFAULT)
 813                 batadv_tvlv_containers_process(bat_priv, true, orig_node,
 814                                                NULL, NULL,
 815                                                (unsigned char *)(ogm2 + 1),
 816                                                ntohs(ogm2->tvlv_len));
 817
 818         /* if the metric update went through, update routes if needed */
 819         forward = batadv_v_ogm_route_update(bat_priv, ethhdr, ogm2, orig_node,
 820                                             neigh_node, if_incoming,
 821                                             if_outgoing);
 822
 823         /* if the routes have been processed correctly, check and forward */
 824         if (forward)
 825                 batadv_v_ogm_forward(bat_priv, ogm2, orig_node, neigh_node,
 826                                      if_incoming, if_outgoing);
 827 }
 828
 829 /**
 830  * batadv_v_ogm_aggr_packet() - checks if there is another OGM aggregated
 831  * @buff_pos: current position in the skb
 832  * @packet_len: total length of the skb
 833  * @ogm2_packet: potential OGM2 in buffer
 834  *
 835  * Return: true if there is enough space for another OGM, false otherwise.
 836  */
 837 static bool
 838 batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
 839                          const struct batadv_ogm2_packet *ogm2_packet)
 840 {
 841         int next_buff_pos = 0;
 842
 843         /* check if there is enough space for the header */
 844         next_buff_pos += buff_pos + sizeof(*ogm2_packet);
 845         if (next_buff_pos > packet_len)
 846                 return false;
 847
 848         /* check if there is enough space for the optional TVLV */
 849         next_buff_pos += ntohs(ogm2_packet->tvlv_len);
 850
 851         return (next_buff_pos <= packet_len) &&
 852                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
 853 }
 854
 855 /**
 856  * batadv_v_ogm_process() - process an incoming batman v OGM
 857  * @skb: the skb containing the OGM
 858  * @ogm_offset: offset to the OGM which should be processed (for aggregates)
 859  * @if_incoming: the interface where this packet was received
 860  */
 861 static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
 862                                  struct batadv_hard_iface *if_incoming)
 863 {
 864         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 865         struct ethhdr *ethhdr;
 866         struct batadv_orig_node *orig_node = NULL;
 867         struct batadv_hardif_neigh_node *hardif_neigh = NULL;
 868         struct batadv_neigh_node *neigh_node = NULL;
 869         struct batadv_hard_iface *hard_iface;
 870         struct batadv_ogm2_packet *ogm_packet;
 871         u32 ogm_throughput, link_throughput, path_throughput;
 872         int ret;
 873
 874         ethhdr = eth_hdr(skb);
 875         ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
 876
 877         ogm_throughput = ntohl(ogm_packet->throughput);
 878
 879         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 880                    "Received OGM2 packet via NB: %pM, IF: %s [%pM] (from OG: %pM, seqno %u, throughput %u, TTL %u, V %u, tvlv_len %u)\n",
 881                    ethhdr->h_source, if_incoming->net_dev->name,
 882                    if_incoming->net_dev->dev_addr, ogm_packet->orig,
 883                    ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
 884                    ogm_packet->version, ntohs(ogm_packet->tvlv_len));
 885
 886         if (batadv_is_my_mac(bat_priv, ogm_packet->orig)) {
 887                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 888                            "Drop packet: originator packet from ourself\n");
 889                 return;
 890         }
 891
 892         /* If the throughput metric is 0, immediately drop the packet. No need
 893          * to create orig_node / neigh_node for an unusable route.
 894          */
 895         if (ogm_throughput == 0) {
 896                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 897                            "Drop packet: originator packet with throughput metric of 0\n");
 898                 return;
 899         }
 900
 901         /* require ELP packets be to received from this neighbor first */
 902         hardif_neigh = batadv_hardif_neigh_get(if_incoming, ethhdr->h_source);
 903         if (!hardif_neigh) {
 904                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 905                            "Drop packet: OGM via unknown neighbor!\n");
 906                 goto out;
 907         }
 908
 909         orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
 910         if (!orig_node)
 911                 goto out;
 912
 913         neigh_node = batadv_neigh_node_get_or_create(orig_node, if_incoming,
 914                                                      ethhdr->h_source);
 915         if (!neigh_node)
 916                 goto out;
 917
 918         /* Update the received throughput metric to match the link
 919          * characteristic:
 920          *  - If this OGM traveled one hop so far (emitted by single hop
 921          *    neighbor) the path throughput metric equals the link throughput.
 922          *  - For OGMs traversing more than hop the path throughput metric is
 923          *    the smaller of the path throughput and the link throughput.
 924          */
 925         link_throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
 926         path_throughput = min_t(u32, link_throughput, ogm_throughput);
 927         ogm_packet->throughput = htonl(path_throughput);
 928
 929         batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet, orig_node,
 930                                        neigh_node, if_incoming,
 931                                        BATADV_IF_DEFAULT);
 932
 933         rcu_read_lock();
 934         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 935                 if (hard_iface->if_status != BATADV_IF_ACTIVE)
 936                         continue;
 937
 938                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 939                         continue;
 940
 941                 if (!kref_get_unless_zero(&hard_iface->refcount))
 942                         continue;
 943
 944                 ret = batadv_hardif_no_broadcast(hard_iface,
 945                                                  ogm_packet->orig,
 946                                                  hardif_neigh->orig);
 947
 948                 if (ret) {
 949                         char *type;
 950
 951                         switch (ret) {
 952                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 953                                 type = "no neighbor";
 954                                 break;
 955                         case BATADV_HARDIF_BCAST_DUPFWD:
 956                                 type = "single neighbor is source";
 957                                 break;
 958                         case BATADV_HARDIF_BCAST_DUPORIG:
 959                                 type = "single neighbor is originator";
 960                                 break;
 961                         default:
 962                                 type = "unknown";
 963                         }
 964
 965                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 packet from %pM on %s suppressed: %s\n",
 966                                    ogm_packet->orig, hard_iface->net_dev->name,
 967                                    type);
 968
 969                         batadv_hardif_put(hard_iface);
 970                         continue;
 971                 }
 972
 973                 batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,
 974                                                orig_node, neigh_node,
 975                                                if_incoming, hard_iface);
 976
 977                 batadv_hardif_put(hard_iface);
 978         }
 979         rcu_read_unlock();
 980 out:
 981         if (orig_node)
 982                 batadv_orig_node_put(orig_node);
 983         if (neigh_node)
 984                 batadv_neigh_node_put(neigh_node);
 985         if (hardif_neigh)
 986                 batadv_hardif_neigh_put(hardif_neigh);
 987 }
 988
 989 /**
 990  * batadv_v_ogm_packet_recv() - OGM2 receiving handler
 991  * @skb: the received OGM
 992  * @if_incoming: the interface where this OGM has been received
 993  *
 994  * Return: NET_RX_SUCCESS and consume the skb on success or returns NET_RX_DROP
 995  * (without freeing the skb) on failure
 996  */
 997 int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 998                              struct batadv_hard_iface *if_incoming)
 999 {
1000         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
1001         struct batadv_ogm2_packet *ogm_packet;
1002         struct ethhdr *ethhdr = eth_hdr(skb);
1003         int ogm_offset;
1004         u8 *packet_pos;
1005         int ret = NET_RX_DROP;
1006
1007         /* did we receive a OGM2 packet on an interface that does not have
1008          * B.A.T.M.A.N. V enabled ?
1009          */
1010         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
1011                 goto free_skb;
1012
1013         if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
1014                 goto free_skb;
1015
1016         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1017                 goto free_skb;
1018
1019         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
1020         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
1021                            skb->len + ETH_HLEN);
1022
1023         ogm_offset = 0;
1024         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
1025
1026         while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
1027                                         ogm_packet)) {
1028                 batadv_v_ogm_process(skb, ogm_offset, if_incoming);
1029
1030                 ogm_offset += BATADV_OGM2_HLEN;
1031                 ogm_offset += ntohs(ogm_packet->tvlv_len);
1032
1033                 packet_pos = skb->data + ogm_offset;
1034                 ogm_packet = (struct batadv_ogm2_packet *)packet_pos;
1035         }
1036
1037         ret = NET_RX_SUCCESS;
1038
1039 free_skb:
1040         if (ret == NET_RX_SUCCESS)
1041                 consume_skb(skb);
1042         else
1043                 kfree_skb(skb);
1044
1045         return ret;
1046 }
1047
1048 /**
1049  * batadv_v_ogm_init() - initialise the OGM2 engine
1050  * @bat_priv: the bat priv with all the soft interface information
1051  *
1052  * Return: 0 on success or a negative error code in case of failure
1053  */
1054 int batadv_v_ogm_init(struct batadv_priv *bat_priv)
1055 {
1056         struct batadv_ogm2_packet *ogm_packet;
1057         unsigned char *ogm_buff;
1058         u32 random_seqno;
1059
1060         bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
1061         ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
1062         if (!ogm_buff)
1063                 return -ENOMEM;
1064
1065         bat_priv->bat_v.ogm_buff = ogm_buff;
1066         ogm_packet = (struct batadv_ogm2_packet *)ogm_buff;
1067         ogm_packet->packet_type = BATADV_OGM2;
1068         ogm_packet->version = BATADV_COMPAT_VERSION;
1069         ogm_packet->ttl = BATADV_TTL;
1070         ogm_packet->flags = BATADV_NO_FLAGS;
1071         ogm_packet->throughput = htonl(BATADV_THROUGHPUT_MAX_VALUE);
1072
1073         /* randomize initial seqno to avoid collision */
1074         get_random_bytes(&random_seqno, sizeof(random_seqno));
1075         atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
1076         INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
1077
1078         mutex_init(&bat_priv->bat_v.ogm_buff_mutex);
1079
1080         return 0;
1081 }
1082
1083 /**
1084  * batadv_v_ogm_free() - free OGM private resources
1085  * @bat_priv: the bat priv with all the soft interface information
1086  */
1087 void batadv_v_ogm_free(struct batadv_priv *bat_priv)
1088 {
1089         cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
1090
1091         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
1092
1093         kfree(bat_priv->bat_v.ogm_buff);
1094         bat_priv->bat_v.ogm_buff = NULL;
1095         bat_priv->bat_v.ogm_buff_len = 0;
1096
1097         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
1098 }