net/batman-adv/bat_v_ogm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2013-2019  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/netdevice.h>
  22 #include <linux/random.h>
  23 #include <linux/rculist.h>
  24 #include <linux/rcupdate.h>
  25 #include <linux/skbuff.h>
  26 #include <linux/slab.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/stddef.h>
  29 #include <linux/string.h>
  30 #include <linux/types.h>
  31 #include <linux/workqueue.h>
  32 #include <uapi/linux/batadv_packet.h>
  33
  34 #include "bat_algo.h"
  35 #include "hard-interface.h"
  36 #include "hash.h"
  37 #include "log.h"
  38 #include "originator.h"
  39 #include "routing.h"
  40 #include "send.h"
  41 #include "translation-table.h"
  42 #include "tvlv.h"
  43
  44 /**
  45  * batadv_v_ogm_orig_get() - retrieve and possibly create an originator node
  46  * @bat_priv: the bat priv with all the soft interface information
  47  * @addr: the address of the originator
  48  *
  49  * Return: the orig_node corresponding to the specified address. If such object
  50  * does not exist it is allocated here. In case of allocation failure returns
  51  * NULL.
  52  */
  53 struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv,
  54                                                const u8 *addr)
  55 {
  56         struct batadv_orig_node *orig_node;
  57         int hash_added;
  58
  59         orig_node = batadv_orig_hash_find(bat_priv, addr);
  60         if (orig_node)
  61                 return orig_node;
  62
  63         orig_node = batadv_orig_node_new(bat_priv, addr);
  64         if (!orig_node)
  65                 return NULL;
  66
  67         kref_get(&orig_node->refcount);
  68         hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
  69                                      batadv_choose_orig, orig_node,
  70                                      &orig_node->hash_entry);
  71         if (hash_added != 0) {
  72                 /* remove refcnt for newly created orig_node and hash entry */
  73                 batadv_orig_node_put(orig_node);
  74                 batadv_orig_node_put(orig_node);
  75                 orig_node = NULL;
  76         }
  77
  78         return orig_node;
  79 }
  80
  81 /**
  82  * batadv_v_ogm_start_queue_timer() - restart the OGM aggregation timer
  83  * @hard_iface: the interface to use to send the OGM
  84  */
  85 static void batadv_v_ogm_start_queue_timer(struct batadv_hard_iface *hard_iface)
  86 {
  87         unsigned int msecs = BATADV_MAX_AGGREGATION_MS * 1000;
  88
  89         /* msecs * [0.9, 1.1] */
  90         msecs += prandom_u32() % (msecs / 5) - (msecs / 10);
  91         queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.aggr_wq,
  92                            msecs_to_jiffies(msecs / 1000));
  93 }
  94
  95 /**
  96  * batadv_v_ogm_start_timer() - restart the OGM sending timer
  97  * @bat_priv: the bat priv with all the soft interface information
  98  */
  99 static void batadv_v_ogm_start_timer(struct batadv_priv *bat_priv)
 100 {
 101         unsigned long msecs;
 102         /* this function may be invoked in different contexts (ogm rescheduling
 103          * or hard_iface activation), but the work timer should not be reset
 104          */
 105         if (delayed_work_pending(&bat_priv->bat_v.ogm_wq))
 106                 return;
 107
 108         msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER;
 109         msecs += prandom_u32() % (2 * BATADV_JITTER);
 110         queue_delayed_work(batadv_event_workqueue, &bat_priv->bat_v.ogm_wq,
 111                            msecs_to_jiffies(msecs));
 112 }
 113
 114 /**
 115  * batadv_v_ogm_send_to_if() - send a batman ogm using a given interface
 116  * @skb: the OGM to send
 117  * @hard_iface: the interface to use to send the OGM
 118  */
 119 static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
 120                                     struct batadv_hard_iface *hard_iface)
 121 {
 122         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 123
 124         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 125                 return;
 126
 127         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
 128         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
 129                            skb->len + ETH_HLEN);
 130
 131         batadv_send_broadcast_skb(skb, hard_iface);
 132 }
 133
 134 /**
 135  * batadv_v_ogm_len() - OGMv2 packet length
 136  * @skb: the OGM to check
 137  *
 138  * Return: Length of the given OGMv2 packet, including tvlv length, excluding
 139  * ethernet header length.
 140  */
 141 static unsigned int batadv_v_ogm_len(struct sk_buff *skb)
 142 {
 143         struct batadv_ogm2_packet *ogm_packet;
 144
 145         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 146         return BATADV_OGM2_HLEN + ntohs(ogm_packet->tvlv_len);
 147 }
 148
 149 /**
 150  * batadv_v_ogm_queue_left() - check if given OGM still fits aggregation queue
 151  * @skb: the OGM to check
 152  * @hard_iface: the interface to use to send the OGM
 153  *
 154  * Caller needs to hold the hard_iface->bat_v.aggr_list_lock.
 155  *
 156  * Return: True, if the given OGMv2 packet still fits, false otherwise.
 157  */
 158 static bool batadv_v_ogm_queue_left(struct sk_buff *skb,
 159                                     struct batadv_hard_iface *hard_iface)
 160 {
 161         unsigned int max = min_t(unsigned int, hard_iface->net_dev->mtu,
 162                                  BATADV_MAX_AGGREGATION_BYTES);
 163         unsigned int ogm_len = batadv_v_ogm_len(skb);
 164
 165         lockdep_assert_held(&hard_iface->bat_v.aggr_list_lock);
 166
 167         return hard_iface->bat_v.aggr_len + ogm_len <= max;
 168 }
 169
 170 /**
 171  * batadv_v_ogm_aggr_list_free - free all elements in an aggregation queue
 172  * @hard_iface: the interface holding the aggregation queue
 173  *
 174  * Empties the OGMv2 aggregation queue and frees all the skbs it contained.
 175  *
 176  * Caller needs to hold the hard_iface->bat_v.aggr_list_lock.
 177  */
 178 static void batadv_v_ogm_aggr_list_free(struct batadv_hard_iface *hard_iface)
 179 {
 180         struct sk_buff *skb;
 181
 182         lockdep_assert_held(&hard_iface->bat_v.aggr_list_lock);
 183
 184         while ((skb = skb_dequeue(&hard_iface->bat_v.aggr_list)))
 185                 kfree_skb(skb);
 186
 187         hard_iface->bat_v.aggr_len = 0;
 188 }
 189
 190 /**
 191  * batadv_v_ogm_aggr_send() - flush & send aggregation queue
 192  * @hard_iface: the interface with the aggregation queue to flush
 193  *
 194  * Aggregates all OGMv2 packets currently in the aggregation queue into a
 195  * single OGMv2 packet and transmits this aggregate.
 196  *
 197  * The aggregation queue is empty after this call.
 198  *
 199  * Caller needs to hold the hard_iface->bat_v.aggr_list_lock.
 200  */
 201 static void batadv_v_ogm_aggr_send(struct batadv_hard_iface *hard_iface)
 202 {
 203         unsigned int aggr_len = hard_iface->bat_v.aggr_len;
 204         struct sk_buff *skb_aggr;
 205         unsigned int ogm_len;
 206         struct sk_buff *skb;
 207
 208         lockdep_assert_held(&hard_iface->bat_v.aggr_list_lock);
 209
 210         if (!aggr_len)
 211                 return;
 212
 213         skb_aggr = dev_alloc_skb(aggr_len + ETH_HLEN + NET_IP_ALIGN);
 214         if (!skb_aggr) {
 215                 batadv_v_ogm_aggr_list_free(hard_iface);
 216                 return;
 217         }
 218
 219         skb_reserve(skb_aggr, ETH_HLEN + NET_IP_ALIGN);
 220         skb_reset_network_header(skb_aggr);
 221
 222         while ((skb = skb_dequeue(&hard_iface->bat_v.aggr_list))) {
 223                 hard_iface->bat_v.aggr_len -= batadv_v_ogm_len(skb);
 224
 225                 ogm_len = batadv_v_ogm_len(skb);
 226                 skb_put_data(skb_aggr, skb->data, ogm_len);
 227
 228                 consume_skb(skb);
 229         }
 230
 231         batadv_v_ogm_send_to_if(skb_aggr, hard_iface);
 232 }
 233
 234 /**
 235  * batadv_v_ogm_queue_on_if() - queue a batman ogm on a given interface
 236  * @skb: the OGM to queue
 237  * @hard_iface: the interface to queue the OGM on
 238  */
 239 static void batadv_v_ogm_queue_on_if(struct sk_buff *skb,
 240                                      struct batadv_hard_iface *hard_iface)
 241 {
 242         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 243
 244         if (!atomic_read(&bat_priv->aggregated_ogms)) {
 245                 batadv_v_ogm_send_to_if(skb, hard_iface);
 246                 return;
 247         }
 248
 249         spin_lock_bh(&hard_iface->bat_v.aggr_list_lock);
 250         if (!batadv_v_ogm_queue_left(skb, hard_iface))
 251                 batadv_v_ogm_aggr_send(hard_iface);
 252
 253         hard_iface->bat_v.aggr_len += batadv_v_ogm_len(skb);
 254         skb_queue_tail(&hard_iface->bat_v.aggr_list, skb);
 255         spin_unlock_bh(&hard_iface->bat_v.aggr_list_lock);
 256 }
 257
 258 /**
 259  * batadv_v_ogm_send() - periodic worker broadcasting the own OGM
 260  * @work: work queue item
 261  */
 262 static void batadv_v_ogm_send(struct work_struct *work)
 263 {
 264         struct batadv_hard_iface *hard_iface;
 265         struct batadv_priv_bat_v *bat_v;
 266         struct batadv_priv *bat_priv;
 267         struct batadv_ogm2_packet *ogm_packet;
 268         struct sk_buff *skb, *skb_tmp;
 269         unsigned char *ogm_buff;
 270         int ogm_buff_len;
 271         u16 tvlv_len = 0;
 272         int ret;
 273
 274         bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
 275         bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
 276
 277         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 278                 goto out;
 279
 280         ogm_buff = bat_priv->bat_v.ogm_buff;
 281         ogm_buff_len = bat_priv->bat_v.ogm_buff_len;
 282         /* tt changes have to be committed before the tvlv data is
 283          * appended as it may alter the tt tvlv container
 284          */
 285         batadv_tt_local_commit_changes(bat_priv);
 286         tvlv_len = batadv_tvlv_container_ogm_append(bat_priv, &ogm_buff,
 287                                                     &ogm_buff_len,
 288                                                     BATADV_OGM2_HLEN);
 289
 290         bat_priv->bat_v.ogm_buff = ogm_buff;
 291         bat_priv->bat_v.ogm_buff_len = ogm_buff_len;
 292
 293         skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + ogm_buff_len);
 294         if (!skb)
 295                 goto reschedule;
 296
 297         skb_reserve(skb, ETH_HLEN);
 298         skb_put_data(skb, ogm_buff, ogm_buff_len);
 299
 300         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 301         ogm_packet->seqno = htonl(atomic_read(&bat_priv->bat_v.ogm_seqno));
 302         atomic_inc(&bat_priv->bat_v.ogm_seqno);
 303         ogm_packet->tvlv_len = htons(tvlv_len);
 304
 305         /* broadcast on every interface */
 306         rcu_read_lock();
 307         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 308                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 309                         continue;
 310
 311                 if (!kref_get_unless_zero(&hard_iface->refcount))
 312                         continue;
 313
 314                 ret = batadv_hardif_no_broadcast(hard_iface, NULL, NULL);
 315                 if (ret) {
 316                         char *type;
 317
 318                         switch (ret) {
 319                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 320                                 type = "no neighbor";
 321                                 break;
 322                         case BATADV_HARDIF_BCAST_DUPFWD:
 323                                 type = "single neighbor is source";
 324                                 break;
 325                         case BATADV_HARDIF_BCAST_DUPORIG:
 326                                 type = "single neighbor is originator";
 327                                 break;
 328                         default:
 329                                 type = "unknown";
 330                         }
 331
 332                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 from ourselves on %s suppressed: %s\n",
 333                                    hard_iface->net_dev->name, type);
 334
 335                         batadv_hardif_put(hard_iface);
 336                         continue;
 337                 }
 338
 339                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 340                            "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",
 341                            ogm_packet->orig, ntohl(ogm_packet->seqno),
 342                            ntohl(ogm_packet->throughput), ogm_packet->ttl,
 343                            hard_iface->net_dev->name,
 344                            hard_iface->net_dev->dev_addr);
 345
 346                 /* this skb gets consumed by batadv_v_ogm_send_to_if() */
 347                 skb_tmp = skb_clone(skb, GFP_ATOMIC);
 348                 if (!skb_tmp) {
 349                         batadv_hardif_put(hard_iface);
 350                         break;
 351                 }
 352
 353                 batadv_v_ogm_queue_on_if(skb_tmp, hard_iface);
 354                 batadv_hardif_put(hard_iface);
 355         }
 356         rcu_read_unlock();
 357
 358         consume_skb(skb);
 359
 360 reschedule:
 361         batadv_v_ogm_start_timer(bat_priv);
 362 out:
 363         return;
 364 }
 365
 366 /**
 367  * batadv_v_ogm_aggr_work() - OGM queue periodic task per interface
 368  * @work: work queue item
 369  *
 370  * Emits aggregated OGM message in regular intervals.
 371  */
 372 void batadv_v_ogm_aggr_work(struct work_struct *work)
 373 {
 374         struct batadv_hard_iface_bat_v *batv;
 375         struct batadv_hard_iface *hard_iface;
 376
 377         batv = container_of(work, struct batadv_hard_iface_bat_v, aggr_wq.work);
 378         hard_iface = container_of(batv, struct batadv_hard_iface, bat_v);
 379
 380         spin_lock_bh(&hard_iface->bat_v.aggr_list_lock);
 381         batadv_v_ogm_aggr_send(hard_iface);
 382         spin_unlock_bh(&hard_iface->bat_v.aggr_list_lock);
 383
 384         batadv_v_ogm_start_queue_timer(hard_iface);
 385 }
 386
 387 /**
 388  * batadv_v_ogm_iface_enable() - prepare an interface for B.A.T.M.A.N. V
 389  * @hard_iface: the interface to prepare
 390  *
 391  * Takes care of scheduling own OGM sending routine for this interface.
 392  *
 393  * Return: 0 on success or a negative error code otherwise
 394  */
 395 int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 396 {
 397         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 398
 399         batadv_v_ogm_start_queue_timer(hard_iface);
 400         batadv_v_ogm_start_timer(bat_priv);
 401
 402         return 0;
 403 }
 404
 405 /**
 406  * batadv_v_ogm_iface_disable() - release OGM interface private resources
 407  * @hard_iface: interface for which the resources have to be released
 408  */
 409 void batadv_v_ogm_iface_disable(struct batadv_hard_iface *hard_iface)
 410 {
 411         cancel_delayed_work_sync(&hard_iface->bat_v.aggr_wq);
 412
 413         spin_lock_bh(&hard_iface->bat_v.aggr_list_lock);
 414         batadv_v_ogm_aggr_list_free(hard_iface);
 415         spin_unlock_bh(&hard_iface->bat_v.aggr_list_lock);
 416 }
 417
 418 /**
 419  * batadv_v_ogm_primary_iface_set() - set a new primary interface
 420  * @primary_iface: the new primary interface
 421  */
 422 void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
 423 {
 424         struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
 425         struct batadv_ogm2_packet *ogm_packet;
 426
 427         if (!bat_priv->bat_v.ogm_buff)
 428                 return;
 429
 430         ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
 431         ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
 432 }
 433
 434 /**
 435  * batadv_v_forward_penalty() - apply a penalty to the throughput metric
 436  *  forwarded with B.A.T.M.A.N. V OGMs
 437  * @bat_priv: the bat priv with all the soft interface information
 438  * @if_incoming: the interface where the OGM has been received
 439  * @if_outgoing: the interface where the OGM has to be forwarded to
 440  * @throughput: the current throughput
 441  *
 442  * Apply a penalty on the current throughput metric value based on the
 443  * characteristic of the interface where the OGM has been received. The return
 444  * value is computed as follows:
 445  * - throughput * 50%          if the incoming and outgoing interface are the
 446  *                             same WiFi interface and the throughput is above
 447  *                             1MBit/s
 448  * - throughput                if the outgoing interface is the default
 449  *                             interface (i.e. this OGM is processed for the
 450  *                             internal table and not forwarded)
 451  * - throughput * hop penalty  otherwise
 452  *
 453  * Return: the penalised throughput metric.
 454  */
 455 static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv,
 456                                     struct batadv_hard_iface *if_incoming,
 457                                     struct batadv_hard_iface *if_outgoing,
 458                                     u32 throughput)
 459 {
 460         int hop_penalty = atomic_read(&bat_priv->hop_penalty);
 461         int hop_penalty_max = BATADV_TQ_MAX_VALUE;
 462
 463         /* Don't apply hop penalty in default originator table. */
 464         if (if_outgoing == BATADV_IF_DEFAULT)
 465                 return throughput;
 466
 467         /* Forwarding on the same WiFi interface cuts the throughput in half
 468          * due to the store & forward characteristics of WIFI.
 469          * Very low throughput values are the exception.
 470          */
 471         if (throughput > 10 &&
 472             if_incoming == if_outgoing &&
 473             !(if_incoming->bat_v.flags & BATADV_FULL_DUPLEX))
 474                 return throughput / 2;
 475
 476         /* hop penalty of 255 equals 100% */
 477         return throughput * (hop_penalty_max - hop_penalty) / hop_penalty_max;
 478 }
 479
 480 /**
 481  * batadv_v_ogm_forward() - check conditions and forward an OGM to the given
 482  *  outgoing interface
 483  * @bat_priv: the bat priv with all the soft interface information
 484  * @ogm_received: previously received OGM to be forwarded
 485  * @orig_node: the originator which has been updated
 486  * @neigh_node: the neigh_node through with the OGM has been received
 487  * @if_incoming: the interface on which this OGM was received on
 488  * @if_outgoing: the interface to which the OGM has to be forwarded to
 489  *
 490  * Forward an OGM to an interface after having altered the throughput metric and
 491  * the TTL value contained in it. The original OGM isn't modified.
 492  */
 493 static void batadv_v_ogm_forward(struct batadv_priv *bat_priv,
 494                                  const struct batadv_ogm2_packet *ogm_received,
 495                                  struct batadv_orig_node *orig_node,
 496                                  struct batadv_neigh_node *neigh_node,
 497                                  struct batadv_hard_iface *if_incoming,
 498                                  struct batadv_hard_iface *if_outgoing)
 499 {
 500         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 501         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 502         struct batadv_neigh_node *router = NULL;
 503         struct batadv_ogm2_packet *ogm_forward;
 504         unsigned char *skb_buff;
 505         struct sk_buff *skb;
 506         size_t packet_len;
 507         u16 tvlv_len;
 508
 509         /* only forward for specific interfaces, not for the default one. */
 510         if (if_outgoing == BATADV_IF_DEFAULT)
 511                 goto out;
 512
 513         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 514         if (!orig_ifinfo)
 515                 goto out;
 516
 517         /* acquire possibly updated router */
 518         router = batadv_orig_router_get(orig_node, if_outgoing);
 519
 520         /* strict rule: forward packets coming from the best next hop only */
 521         if (neigh_node != router)
 522                 goto out;
 523
 524         /* don't forward the same seqno twice on one interface */
 525         if (orig_ifinfo->last_seqno_forwarded == ntohl(ogm_received->seqno))
 526                 goto out;
 527
 528         orig_ifinfo->last_seqno_forwarded = ntohl(ogm_received->seqno);
 529
 530         if (ogm_received->ttl <= 1) {
 531                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
 532                 goto out;
 533         }
 534
 535         neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 536         if (!neigh_ifinfo)
 537                 goto out;
 538
 539         tvlv_len = ntohs(ogm_received->tvlv_len);
 540
 541         packet_len = BATADV_OGM2_HLEN + tvlv_len;
 542         skb = netdev_alloc_skb_ip_align(if_outgoing->net_dev,
 543                                         ETH_HLEN + packet_len);
 544         if (!skb)
 545                 goto out;
 546
 547         skb_reserve(skb, ETH_HLEN);
 548         skb_buff = skb_put_data(skb, ogm_received, packet_len);
 549
 550         /* apply forward penalty */
 551         ogm_forward = (struct batadv_ogm2_packet *)skb_buff;
 552         ogm_forward->throughput = htonl(neigh_ifinfo->bat_v.throughput);
 553         ogm_forward->ttl--;
 554
 555         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 556                    "Forwarding OGM2 packet on %s: throughput %u, ttl %u, received via %s\n",
 557                    if_outgoing->net_dev->name, ntohl(ogm_forward->throughput),
 558                    ogm_forward->ttl, if_incoming->net_dev->name);
 559
 560         batadv_v_ogm_queue_on_if(skb, if_outgoing);
 561
 562 out:
 563         if (orig_ifinfo)
 564                 batadv_orig_ifinfo_put(orig_ifinfo);
 565         if (router)
 566                 batadv_neigh_node_put(router);
 567         if (neigh_ifinfo)
 568                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 569 }
 570
 571 /**
 572  * batadv_v_ogm_metric_update() - update route metric based on OGM
 573  * @bat_priv: the bat priv with all the soft interface information
 574  * @ogm2: OGM2 structure
 575  * @orig_node: Originator structure for which the OGM has been received
 576  * @neigh_node: the neigh_node through with the OGM has been received
 577  * @if_incoming: the interface where this packet was received
 578  * @if_outgoing: the interface for which the packet should be considered
 579  *
 580  * Return:
 581  *  1  if the OGM is new,
 582  *  0  if it is not new but valid,
 583  *  <0 on error (e.g. old OGM)
 584  */
 585 static int batadv_v_ogm_metric_update(struct batadv_priv *bat_priv,
 586                                       const struct batadv_ogm2_packet *ogm2,
 587                                       struct batadv_orig_node *orig_node,
 588                                       struct batadv_neigh_node *neigh_node,
 589                                       struct batadv_hard_iface *if_incoming,
 590                                       struct batadv_hard_iface *if_outgoing)
 591 {
 592         struct batadv_orig_ifinfo *orig_ifinfo;
 593         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 594         bool protection_started = false;
 595         int ret = -EINVAL;
 596         u32 path_throughput;
 597         s32 seq_diff;
 598
 599         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 600         if (!orig_ifinfo)
 601                 goto out;
 602
 603         seq_diff = ntohl(ogm2->seqno) - orig_ifinfo->last_real_seqno;
 604
 605         if (!hlist_empty(&orig_node->neigh_list) &&
 606             batadv_window_protected(bat_priv, seq_diff,
 607                                     BATADV_OGM_MAX_AGE,
 608                                     &orig_ifinfo->batman_seqno_reset,
 609                                     &protection_started)) {
 610                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 611                            "Drop packet: packet within window protection time from %pM\n",
 612                            ogm2->orig);
 613                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 614                            "Last reset: %ld, %ld\n",
 615                            orig_ifinfo->batman_seqno_reset, jiffies);
 616                 goto out;
 617         }
 618
 619         /* drop packets with old seqnos, however accept the first packet after
 620          * a host has been rebooted.
 621          */
 622         if (seq_diff < 0 && !protection_started)
 623                 goto out;
 624
 625         neigh_node->last_seen = jiffies;
 626
 627         orig_node->last_seen = jiffies;
 628
 629         orig_ifinfo->last_real_seqno = ntohl(ogm2->seqno);
 630         orig_ifinfo->last_ttl = ogm2->ttl;
 631
 632         neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
 633         if (!neigh_ifinfo)
 634                 goto out;
 635
 636         path_throughput = batadv_v_forward_penalty(bat_priv, if_incoming,
 637                                                    if_outgoing,
 638                                                    ntohl(ogm2->throughput));
 639         neigh_ifinfo->bat_v.throughput = path_throughput;
 640         neigh_ifinfo->bat_v.last_seqno = ntohl(ogm2->seqno);
 641         neigh_ifinfo->last_ttl = ogm2->ttl;
 642
 643         if (seq_diff > 0 || protection_started)
 644                 ret = 1;
 645         else
 646                 ret = 0;
 647 out:
 648         if (orig_ifinfo)
 649                 batadv_orig_ifinfo_put(orig_ifinfo);
 650         if (neigh_ifinfo)
 651                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 652
 653         return ret;
 654 }
 655
 656 /**
 657  * batadv_v_ogm_route_update() - update routes based on OGM
 658  * @bat_priv: the bat priv with all the soft interface information
 659  * @ethhdr: the Ethernet header of the OGM2
 660  * @ogm2: OGM2 structure
 661  * @orig_node: Originator structure for which the OGM has been received
 662  * @neigh_node: the neigh_node through with the OGM has been received
 663  * @if_incoming: the interface where this packet was received
 664  * @if_outgoing: the interface for which the packet should be considered
 665  *
 666  * Return: true if the packet should be forwarded, false otherwise
 667  */
 668 static bool batadv_v_ogm_route_update(struct batadv_priv *bat_priv,
 669                                       const struct ethhdr *ethhdr,
 670                                       const struct batadv_ogm2_packet *ogm2,
 671                                       struct batadv_orig_node *orig_node,
 672                                       struct batadv_neigh_node *neigh_node,
 673                                       struct batadv_hard_iface *if_incoming,
 674                                       struct batadv_hard_iface *if_outgoing)
 675 {
 676         struct batadv_neigh_node *router = NULL;
 677         struct batadv_orig_node *orig_neigh_node;
 678         struct batadv_neigh_node *orig_neigh_router = NULL;
 679         struct batadv_neigh_ifinfo *router_ifinfo = NULL, *neigh_ifinfo = NULL;
 680         u32 router_throughput, neigh_throughput;
 681         u32 router_last_seqno;
 682         u32 neigh_last_seqno;
 683         s32 neigh_seq_diff;
 684         bool forward = false;
 685
 686         orig_neigh_node = batadv_v_ogm_orig_get(bat_priv, ethhdr->h_source);
 687         if (!orig_neigh_node)
 688                 goto out;
 689
 690         orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
 691                                                    if_outgoing);
 692
 693         /* drop packet if sender is not a direct neighbor and if we
 694          * don't route towards it
 695          */
 696         router = batadv_orig_router_get(orig_node, if_outgoing);
 697         if (router && router->orig_node != orig_node && !orig_neigh_router) {
 698                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 699                            "Drop packet: OGM via unknown neighbor!\n");
 700                 goto out;
 701         }
 702
 703         /* Mark the OGM to be considered for forwarding, and update routes
 704          * if needed.
 705          */
 706         forward = true;
 707
 708         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 709                    "Searching and updating originator entry of received packet\n");
 710
 711         /* if this neighbor already is our next hop there is nothing
 712          * to change
 713          */
 714         if (router == neigh_node)
 715                 goto out;
 716
 717         /* don't consider neighbours with worse throughput.
 718          * also switch route if this seqno is BATADV_V_MAX_ORIGDIFF newer than
 719          * the last received seqno from our best next hop.
 720          */
 721         if (router) {
 722                 router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
 723                 neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 724
 725                 /* if these are not allocated, something is wrong. */
 726                 if (!router_ifinfo || !neigh_ifinfo)
 727                         goto out;
 728
 729                 neigh_last_seqno = neigh_ifinfo->bat_v.last_seqno;
 730                 router_last_seqno = router_ifinfo->bat_v.last_seqno;
 731                 neigh_seq_diff = neigh_last_seqno - router_last_seqno;
 732                 router_throughput = router_ifinfo->bat_v.throughput;
 733                 neigh_throughput = neigh_ifinfo->bat_v.throughput;
 734
 735                 if (neigh_seq_diff < BATADV_OGM_MAX_ORIGDIFF &&
 736                     router_throughput >= neigh_throughput)
 737                         goto out;
 738         }
 739
 740         batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
 741 out:
 742         if (router)
 743                 batadv_neigh_node_put(router);
 744         if (orig_neigh_router)
 745                 batadv_neigh_node_put(orig_neigh_router);
 746         if (orig_neigh_node)
 747                 batadv_orig_node_put(orig_neigh_node);
 748         if (router_ifinfo)
 749                 batadv_neigh_ifinfo_put(router_ifinfo);
 750         if (neigh_ifinfo)
 751                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 752
 753         return forward;
 754 }
 755
 756 /**
 757  * batadv_v_ogm_process_per_outif() - process a batman v OGM for an outgoing if
 758  * @bat_priv: the bat priv with all the soft interface information
 759  * @ethhdr: the Ethernet header of the OGM2
 760  * @ogm2: OGM2 structure
 761  * @orig_node: Originator structure for which the OGM has been received
 762  * @neigh_node: the neigh_node through with the OGM has been received
 763  * @if_incoming: the interface where this packet was received
 764  * @if_outgoing: the interface for which the packet should be considered
 765  */
 766 static void
 767 batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
 768                                const struct ethhdr *ethhdr,
 769                                const struct batadv_ogm2_packet *ogm2,
 770                                struct batadv_orig_node *orig_node,
 771                                struct batadv_neigh_node *neigh_node,
 772                                struct batadv_hard_iface *if_incoming,
 773                                struct batadv_hard_iface *if_outgoing)
 774 {
 775         int seqno_age;
 776         bool forward;
 777
 778         /* first, update the metric with according sanity checks */
 779         seqno_age = batadv_v_ogm_metric_update(bat_priv, ogm2, orig_node,
 780                                                neigh_node, if_incoming,
 781                                                if_outgoing);
 782
 783         /* outdated sequence numbers are to be discarded */
 784         if (seqno_age < 0)
 785                 return;
 786
 787         /* only unknown & newer OGMs contain TVLVs we are interested in */
 788         if (seqno_age > 0 && if_outgoing == BATADV_IF_DEFAULT)
 789                 batadv_tvlv_containers_process(bat_priv, true, orig_node,
 790                                                NULL, NULL,
 791                                                (unsigned char *)(ogm2 + 1),
 792                                                ntohs(ogm2->tvlv_len));
 793
 794         /* if the metric update went through, update routes if needed */
 795         forward = batadv_v_ogm_route_update(bat_priv, ethhdr, ogm2, orig_node,
 796                                             neigh_node, if_incoming,
 797                                             if_outgoing);
 798
 799         /* if the routes have been processed correctly, check and forward */
 800         if (forward)
 801                 batadv_v_ogm_forward(bat_priv, ogm2, orig_node, neigh_node,
 802                                      if_incoming, if_outgoing);
 803 }
 804
 805 /**
 806  * batadv_v_ogm_aggr_packet() - checks if there is another OGM aggregated
 807  * @buff_pos: current position in the skb
 808  * @packet_len: total length of the skb
 809  * @tvlv_len: tvlv length of the previously considered OGM
 810  *
 811  * Return: true if there is enough space for another OGM, false otherwise.
 812  */
 813 static bool batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
 814                                      __be16 tvlv_len)
 815 {
 816         int next_buff_pos = 0;
 817
 818         next_buff_pos += buff_pos + BATADV_OGM2_HLEN;
 819         next_buff_pos += ntohs(tvlv_len);
 820
 821         return (next_buff_pos <= packet_len) &&
 822                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
 823 }
 824
 825 /**
 826  * batadv_v_ogm_process() - process an incoming batman v OGM
 827  * @skb: the skb containing the OGM
 828  * @ogm_offset: offset to the OGM which should be processed (for aggregates)
 829  * @if_incoming: the interface where this packet was receved
 830  */
 831 static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
 832                                  struct batadv_hard_iface *if_incoming)
 833 {
 834         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 835         struct ethhdr *ethhdr;
 836         struct batadv_orig_node *orig_node = NULL;
 837         struct batadv_hardif_neigh_node *hardif_neigh = NULL;
 838         struct batadv_neigh_node *neigh_node = NULL;
 839         struct batadv_hard_iface *hard_iface;
 840         struct batadv_ogm2_packet *ogm_packet;
 841         u32 ogm_throughput, link_throughput, path_throughput;
 842         int ret;
 843
 844         ethhdr = eth_hdr(skb);
 845         ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
 846
 847         ogm_throughput = ntohl(ogm_packet->throughput);
 848
 849         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 850                    "Received OGM2 packet via NB: %pM, IF: %s [%pM] (from OG: %pM, seqno %u, throughput %u, TTL %u, V %u, tvlv_len %u)\n",
 851                    ethhdr->h_source, if_incoming->net_dev->name,
 852                    if_incoming->net_dev->dev_addr, ogm_packet->orig,
 853                    ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
 854                    ogm_packet->version, ntohs(ogm_packet->tvlv_len));
 855
 856         /* If the throughput metric is 0, immediately drop the packet. No need
 857          * to create orig_node / neigh_node for an unusable route.
 858          */
 859         if (ogm_throughput == 0) {
 860                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 861                            "Drop packet: originator packet with throughput metric of 0\n");
 862                 return;
 863         }
 864
 865         /* require ELP packets be to received from this neighbor first */
 866         hardif_neigh = batadv_hardif_neigh_get(if_incoming, ethhdr->h_source);
 867         if (!hardif_neigh) {
 868                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 869                            "Drop packet: OGM via unknown neighbor!\n");
 870                 goto out;
 871         }
 872
 873         orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
 874         if (!orig_node)
 875                 return;
 876
 877         neigh_node = batadv_neigh_node_get_or_create(orig_node, if_incoming,
 878                                                      ethhdr->h_source);
 879         if (!neigh_node)
 880                 goto out;
 881
 882         /* Update the received throughput metric to match the link
 883          * characteristic:
 884          *  - If this OGM traveled one hop so far (emitted by single hop
 885          *    neighbor) the path throughput metric equals the link throughput.
 886          *  - For OGMs traversing more than hop the path throughput metric is
 887          *    the smaller of the path throughput and the link throughput.
 888          */
 889         link_throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
 890         path_throughput = min_t(u32, link_throughput, ogm_throughput);
 891         ogm_packet->throughput = htonl(path_throughput);
 892
 893         batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet, orig_node,
 894                                        neigh_node, if_incoming,
 895                                        BATADV_IF_DEFAULT);
 896
 897         rcu_read_lock();
 898         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 899                 if (hard_iface->if_status != BATADV_IF_ACTIVE)
 900                         continue;
 901
 902                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 903                         continue;
 904
 905                 if (!kref_get_unless_zero(&hard_iface->refcount))
 906                         continue;
 907
 908                 ret = batadv_hardif_no_broadcast(hard_iface,
 909                                                  ogm_packet->orig,
 910                                                  hardif_neigh->orig);
 911
 912                 if (ret) {
 913                         char *type;
 914
 915                         switch (ret) {
 916                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 917                                 type = "no neighbor";
 918                                 break;
 919                         case BATADV_HARDIF_BCAST_DUPFWD:
 920                                 type = "single neighbor is source";
 921                                 break;
 922                         case BATADV_HARDIF_BCAST_DUPORIG:
 923                                 type = "single neighbor is originator";
 924                                 break;
 925                         default:
 926                                 type = "unknown";
 927                         }
 928
 929                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 packet from %pM on %s suppressed: %s\n",
 930                                    ogm_packet->orig, hard_iface->net_dev->name,
 931                                    type);
 932
 933                         batadv_hardif_put(hard_iface);
 934                         continue;
 935                 }
 936
 937                 batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,
 938                                                orig_node, neigh_node,
 939                                                if_incoming, hard_iface);
 940
 941                 batadv_hardif_put(hard_iface);
 942         }
 943         rcu_read_unlock();
 944 out:
 945         if (orig_node)
 946                 batadv_orig_node_put(orig_node);
 947         if (neigh_node)
 948                 batadv_neigh_node_put(neigh_node);
 949         if (hardif_neigh)
 950                 batadv_hardif_neigh_put(hardif_neigh);
 951 }
 952
 953 /**
 954  * batadv_v_ogm_packet_recv() - OGM2 receiving handler
 955  * @skb: the received OGM
 956  * @if_incoming: the interface where this OGM has been received
 957  *
 958  * Return: NET_RX_SUCCESS and consume the skb on success or returns NET_RX_DROP
 959  * (without freeing the skb) on failure
 960  */
 961 int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 962                              struct batadv_hard_iface *if_incoming)
 963 {
 964         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 965         struct batadv_ogm2_packet *ogm_packet;
 966         struct ethhdr *ethhdr = eth_hdr(skb);
 967         int ogm_offset;
 968         u8 *packet_pos;
 969         int ret = NET_RX_DROP;
 970
 971         /* did we receive a OGM2 packet on an interface that does not have
 972          * B.A.T.M.A.N. V enabled ?
 973          */
 974         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 975                 goto free_skb;
 976
 977         if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
 978                 goto free_skb;
 979
 980         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 981                 goto free_skb;
 982
 983         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 984
 985         if (batadv_is_my_mac(bat_priv, ogm_packet->orig))
 986                 goto free_skb;
 987
 988         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
 989         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
 990                            skb->len + ETH_HLEN);
 991
 992         ogm_offset = 0;
 993         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 994
 995         while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
 996                                         ogm_packet->tvlv_len)) {
 997                 batadv_v_ogm_process(skb, ogm_offset, if_incoming);
 998
 999                 ogm_offset += BATADV_OGM2_HLEN;
1000                 ogm_offset += ntohs(ogm_packet->tvlv_len);
1001
1002                 packet_pos = skb->data + ogm_offset;
1003                 ogm_packet = (struct batadv_ogm2_packet *)packet_pos;
1004         }
1005
1006         ret = NET_RX_SUCCESS;
1007
1008 free_skb:
1009         if (ret == NET_RX_SUCCESS)
1010                 consume_skb(skb);
1011         else
1012                 kfree_skb(skb);
1013
1014         return ret;
1015 }
1016
1017 /**
1018  * batadv_v_ogm_init() - initialise the OGM2 engine
1019  * @bat_priv: the bat priv with all the soft interface information
1020  *
1021  * Return: 0 on success or a negative error code in case of failure
1022  */
1023 int batadv_v_ogm_init(struct batadv_priv *bat_priv)
1024 {
1025         struct batadv_ogm2_packet *ogm_packet;
1026         unsigned char *ogm_buff;
1027         u32 random_seqno;
1028
1029         bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
1030         ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
1031         if (!ogm_buff)
1032                 return -ENOMEM;
1033
1034         bat_priv->bat_v.ogm_buff = ogm_buff;
1035         ogm_packet = (struct batadv_ogm2_packet *)ogm_buff;
1036         ogm_packet->packet_type = BATADV_OGM2;
1037         ogm_packet->version = BATADV_COMPAT_VERSION;
1038         ogm_packet->ttl = BATADV_TTL;
1039         ogm_packet->flags = BATADV_NO_FLAGS;
1040         ogm_packet->throughput = htonl(BATADV_THROUGHPUT_MAX_VALUE);
1041
1042         /* randomize initial seqno to avoid collision */
1043         get_random_bytes(&random_seqno, sizeof(random_seqno));
1044         atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
1045         INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
1046
1047         return 0;
1048 }
1049
1050 /**
1051  * batadv_v_ogm_free() - free OGM private resources
1052  * @bat_priv: the bat priv with all the soft interface information
1053  */
1054 void batadv_v_ogm_free(struct batadv_priv *bat_priv)
1055 {
1056         cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
1057
1058         kfree(bat_priv->bat_v.ogm_buff);
1059         bat_priv->bat_v.ogm_buff = NULL;
1060         bat_priv->bat_v.ogm_buff_len = 0;
1061 }