net/batman-adv/bat_v_ogm.c

   1 /* Copyright (C) 2013-2017  B.A.T.M.A.N. contributors:
   2  *
   3  * Antonio Quartulli
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of version 2 of the GNU General Public
   7  * License as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "bat_v_ogm.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/byteorder/generic.h>
  23 #include <linux/errno.h>
  24 #include <linux/etherdevice.h>
  25 #include <linux/fs.h>
  26 #include <linux/if_ether.h>
  27 #include <linux/jiffies.h>
  28 #include <linux/kernel.h>
  29 #include <linux/kref.h>
  30 #include <linux/list.h>
  31 #include <linux/lockdep.h>
  32 #include <linux/mutex.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/random.h>
  35 #include <linux/rculist.h>
  36 #include <linux/rcupdate.h>
  37 #include <linux/skbuff.h>
  38 #include <linux/slab.h>
  39 #include <linux/stddef.h>
  40 #include <linux/string.h>
  41 #include <linux/types.h>
  42 #include <linux/workqueue.h>
  43
  44 #include "bat_algo.h"
  45 #include "hard-interface.h"
  46 #include "hash.h"
  47 #include "log.h"
  48 #include "originator.h"
  49 #include "packet.h"
  50 #include "routing.h"
  51 #include "send.h"
  52 #include "translation-table.h"
  53 #include "tvlv.h"
  54
  55 /**
  56  * batadv_v_ogm_orig_get - retrieve and possibly create an originator node
  57  * @bat_priv: the bat priv with all the soft interface information
  58  * @addr: the address of the originator
  59  *
  60  * Return: the orig_node corresponding to the specified address. If such object
  61  * does not exist it is allocated here. In case of allocation failure returns
  62  * NULL.
  63  */
  64 struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv,
  65                                                const u8 *addr)
  66 {
  67         struct batadv_orig_node *orig_node;
  68         int hash_added;
  69
  70         orig_node = batadv_orig_hash_find(bat_priv, addr);
  71         if (orig_node)
  72                 return orig_node;
  73
  74         orig_node = batadv_orig_node_new(bat_priv, addr);
  75         if (!orig_node)
  76                 return NULL;
  77
  78         kref_get(&orig_node->refcount);
  79         hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
  80                                      batadv_choose_orig, orig_node,
  81                                      &orig_node->hash_entry);
  82         if (hash_added != 0) {
  83                 /* remove refcnt for newly created orig_node and hash entry */
  84                 batadv_orig_node_put(orig_node);
  85                 batadv_orig_node_put(orig_node);
  86                 orig_node = NULL;
  87         }
  88
  89         return orig_node;
  90 }
  91
  92 /**
  93  * batadv_v_ogm_start_timer - restart the OGM sending timer
  94  * @bat_priv: the bat priv with all the soft interface information
  95  */
  96 static void batadv_v_ogm_start_timer(struct batadv_priv *bat_priv)
  97 {
  98         unsigned long msecs;
  99         /* this function may be invoked in different contexts (ogm rescheduling
 100          * or hard_iface activation), but the work timer should not be reset
 101          */
 102         if (delayed_work_pending(&bat_priv->bat_v.ogm_wq))
 103                 return;
 104
 105         msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER;
 106         msecs += prandom_u32() % (2 * BATADV_JITTER);
 107         queue_delayed_work(batadv_event_workqueue, &bat_priv->bat_v.ogm_wq,
 108                            msecs_to_jiffies(msecs));
 109 }
 110
 111 /**
 112  * batadv_v_ogm_send_to_if - send a batman ogm using a given interface
 113  * @skb: the OGM to send
 114  * @hard_iface: the interface to use to send the OGM
 115  */
 116 static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
 117                                     struct batadv_hard_iface *hard_iface)
 118 {
 119         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 120
 121         if (hard_iface->if_status != BATADV_IF_ACTIVE) {
 122                 kfree_skb(skb);
 123                 return;
 124         }
 125
 126         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
 127         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
 128                            skb->len + ETH_HLEN);
 129
 130         batadv_send_broadcast_skb(skb, hard_iface);
 131 }
 132
 133 /**
 134  * batadv_v_ogm_send_softif() - periodic worker broadcasting the own OGM
 135  *  @bat_priv: the bat priv with all the soft interface information
 136  */
 137 static void batadv_v_ogm_send_softif(struct batadv_priv *bat_priv)
 138 {
 139         struct batadv_hard_iface *hard_iface;
 140         struct batadv_ogm2_packet *ogm_packet;
 141         struct sk_buff *skb, *skb_tmp;
 142         unsigned char *ogm_buff;
 143         int ogm_buff_len;
 144         u16 tvlv_len = 0;
 145         int ret;
 146
 147         lockdep_assert_held(&bat_priv->bat_v.ogm_buff_mutex);
 148
 149         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 150                 goto out;
 151
 152         ogm_buff = bat_priv->bat_v.ogm_buff;
 153         ogm_buff_len = bat_priv->bat_v.ogm_buff_len;
 154         /* tt changes have to be committed before the tvlv data is
 155          * appended as it may alter the tt tvlv container
 156          */
 157         batadv_tt_local_commit_changes(bat_priv);
 158         tvlv_len = batadv_tvlv_container_ogm_append(bat_priv, &ogm_buff,
 159                                                     &ogm_buff_len,
 160                                                     BATADV_OGM2_HLEN);
 161
 162         bat_priv->bat_v.ogm_buff = ogm_buff;
 163         bat_priv->bat_v.ogm_buff_len = ogm_buff_len;
 164
 165         skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + ogm_buff_len);
 166         if (!skb)
 167                 goto reschedule;
 168
 169         skb_reserve(skb, ETH_HLEN);
 170         skb_put_data(skb, ogm_buff, ogm_buff_len);
 171
 172         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 173         ogm_packet->seqno = htonl(atomic_read(&bat_priv->bat_v.ogm_seqno));
 174         atomic_inc(&bat_priv->bat_v.ogm_seqno);
 175         ogm_packet->tvlv_len = htons(tvlv_len);
 176
 177         /* broadcast on every interface */
 178         rcu_read_lock();
 179         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 180                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 181                         continue;
 182
 183                 if (!kref_get_unless_zero(&hard_iface->refcount))
 184                         continue;
 185
 186                 ret = batadv_hardif_no_broadcast(hard_iface, NULL, NULL);
 187                 if (ret) {
 188                         char *type;
 189
 190                         switch (ret) {
 191                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 192                                 type = "no neighbor";
 193                                 break;
 194                         case BATADV_HARDIF_BCAST_DUPFWD:
 195                                 type = "single neighbor is source";
 196                                 break;
 197                         case BATADV_HARDIF_BCAST_DUPORIG:
 198                                 type = "single neighbor is originator";
 199                                 break;
 200                         default:
 201                                 type = "unknown";
 202                         }
 203
 204                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 from ourselves on %s suppressed: %s\n",
 205                                    hard_iface->net_dev->name, type);
 206
 207                         batadv_hardif_put(hard_iface);
 208                         continue;
 209                 }
 210
 211                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 212                            "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",
 213                            ogm_packet->orig, ntohl(ogm_packet->seqno),
 214                            ntohl(ogm_packet->throughput), ogm_packet->ttl,
 215                            hard_iface->net_dev->name,
 216                            hard_iface->net_dev->dev_addr);
 217
 218                 /* this skb gets consumed by batadv_v_ogm_send_to_if() */
 219                 skb_tmp = skb_clone(skb, GFP_ATOMIC);
 220                 if (!skb_tmp) {
 221                         batadv_hardif_put(hard_iface);
 222                         break;
 223                 }
 224
 225                 batadv_v_ogm_send_to_if(skb_tmp, hard_iface);
 226                 batadv_hardif_put(hard_iface);
 227         }
 228         rcu_read_unlock();
 229
 230         consume_skb(skb);
 231
 232 reschedule:
 233         batadv_v_ogm_start_timer(bat_priv);
 234 out:
 235         return;
 236 }
 237
 238 /**
 239  * batadv_v_ogm_send() - periodic worker broadcasting the own OGM
 240  * @work: work queue item
 241  */
 242 static void batadv_v_ogm_send(struct work_struct *work)
 243 {
 244         struct batadv_priv_bat_v *bat_v;
 245         struct batadv_priv *bat_priv;
 246
 247         bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
 248         bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
 249
 250         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 251         batadv_v_ogm_send_softif(bat_priv);
 252         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 253 }
 254
 255 /**
 256  * batadv_v_ogm_iface_enable - prepare an interface for B.A.T.M.A.N. V
 257  * @hard_iface: the interface to prepare
 258  *
 259  * Takes care of scheduling own OGM sending routine for this interface.
 260  *
 261  * Return: 0 on success or a negative error code otherwise
 262  */
 263 int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 264 {
 265         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 266
 267         batadv_v_ogm_start_timer(bat_priv);
 268
 269         return 0;
 270 }
 271
 272 /**
 273  * batadv_v_ogm_primary_iface_set - set a new primary interface
 274  * @primary_iface: the new primary interface
 275  */
 276 void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
 277 {
 278         struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
 279         struct batadv_ogm2_packet *ogm_packet;
 280
 281         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 282         if (!bat_priv->bat_v.ogm_buff)
 283                 goto unlock;
 284
 285         ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
 286         ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
 287
 288 unlock:
 289         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 290 }
 291
 292 /**
 293  * batadv_v_forward_penalty - apply a penalty to the throughput metric forwarded
 294  *  with B.A.T.M.A.N. V OGMs
 295  * @bat_priv: the bat priv with all the soft interface information
 296  * @if_incoming: the interface where the OGM has been received
 297  * @if_outgoing: the interface where the OGM has to be forwarded to
 298  * @throughput: the current throughput
 299  *
 300  * Apply a penalty on the current throughput metric value based on the
 301  * characteristic of the interface where the OGM has been received. The return
 302  * value is computed as follows:
 303  * - throughput * 50%          if the incoming and outgoing interface are the
 304  *                             same WiFi interface and the throughput is above
 305  *                             1MBit/s
 306  * - throughput                if the outgoing interface is the default
 307  *                             interface (i.e. this OGM is processed for the
 308  *                             internal table and not forwarded)
 309  * - throughput * hop penalty  otherwise
 310  *
 311  * Return: the penalised throughput metric.
 312  */
 313 static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv,
 314                                     struct batadv_hard_iface *if_incoming,
 315                                     struct batadv_hard_iface *if_outgoing,
 316                                     u32 throughput)
 317 {
 318         int hop_penalty = atomic_read(&bat_priv->hop_penalty);
 319         int hop_penalty_max = BATADV_TQ_MAX_VALUE;
 320
 321         /* Don't apply hop penalty in default originator table. */
 322         if (if_outgoing == BATADV_IF_DEFAULT)
 323                 return throughput;
 324
 325         /* Forwarding on the same WiFi interface cuts the throughput in half
 326          * due to the store & forward characteristics of WIFI.
 327          * Very low throughput values are the exception.
 328          */
 329         if ((throughput > 10) &&
 330             (if_incoming == if_outgoing) &&
 331             !(if_incoming->bat_v.flags & BATADV_FULL_DUPLEX))
 332                 return throughput / 2;
 333
 334         /* hop penalty of 255 equals 100% */
 335         return throughput * (hop_penalty_max - hop_penalty) / hop_penalty_max;
 336 }
 337
 338 /**
 339  * batadv_v_ogm_forward - check conditions and forward an OGM to the given
 340  *  outgoing interface
 341  * @bat_priv: the bat priv with all the soft interface information
 342  * @ogm_received: previously received OGM to be forwarded
 343  * @orig_node: the originator which has been updated
 344  * @neigh_node: the neigh_node through with the OGM has been received
 345  * @if_incoming: the interface on which this OGM was received on
 346  * @if_outgoing: the interface to which the OGM has to be forwarded to
 347  *
 348  * Forward an OGM to an interface after having altered the throughput metric and
 349  * the TTL value contained in it. The original OGM isn't modified.
 350  */
 351 static void batadv_v_ogm_forward(struct batadv_priv *bat_priv,
 352                                  const struct batadv_ogm2_packet *ogm_received,
 353                                  struct batadv_orig_node *orig_node,
 354                                  struct batadv_neigh_node *neigh_node,
 355                                  struct batadv_hard_iface *if_incoming,
 356                                  struct batadv_hard_iface *if_outgoing)
 357 {
 358         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 359         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 360         struct batadv_neigh_node *router = NULL;
 361         struct batadv_ogm2_packet *ogm_forward;
 362         unsigned char *skb_buff;
 363         struct sk_buff *skb;
 364         size_t packet_len;
 365         u16 tvlv_len;
 366
 367         /* only forward for specific interfaces, not for the default one. */
 368         if (if_outgoing == BATADV_IF_DEFAULT)
 369                 goto out;
 370
 371         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 372         if (!orig_ifinfo)
 373                 goto out;
 374
 375         /* acquire possibly updated router */
 376         router = batadv_orig_router_get(orig_node, if_outgoing);
 377
 378         /* strict rule: forward packets coming from the best next hop only */
 379         if (neigh_node != router)
 380                 goto out;
 381
 382         /* don't forward the same seqno twice on one interface */
 383         if (orig_ifinfo->last_seqno_forwarded == ntohl(ogm_received->seqno))
 384                 goto out;
 385
 386         orig_ifinfo->last_seqno_forwarded = ntohl(ogm_received->seqno);
 387
 388         if (ogm_received->ttl <= 1) {
 389                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
 390                 goto out;
 391         }
 392
 393         neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 394         if (!neigh_ifinfo)
 395                 goto out;
 396
 397         tvlv_len = ntohs(ogm_received->tvlv_len);
 398
 399         packet_len = BATADV_OGM2_HLEN + tvlv_len;
 400         skb = netdev_alloc_skb_ip_align(if_outgoing->net_dev,
 401                                         ETH_HLEN + packet_len);
 402         if (!skb)
 403                 goto out;
 404
 405         skb_reserve(skb, ETH_HLEN);
 406         skb_buff = skb_put_data(skb, ogm_received, packet_len);
 407
 408         /* apply forward penalty */
 409         ogm_forward = (struct batadv_ogm2_packet *)skb_buff;
 410         ogm_forward->throughput = htonl(neigh_ifinfo->bat_v.throughput);
 411         ogm_forward->ttl--;
 412
 413         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 414                    "Forwarding OGM2 packet on %s: throughput %u, ttl %u, received via %s\n",
 415                    if_outgoing->net_dev->name, ntohl(ogm_forward->throughput),
 416                    ogm_forward->ttl, if_incoming->net_dev->name);
 417
 418         batadv_v_ogm_send_to_if(skb, if_outgoing);
 419
 420 out:
 421         if (orig_ifinfo)
 422                 batadv_orig_ifinfo_put(orig_ifinfo);
 423         if (router)
 424                 batadv_neigh_node_put(router);
 425         if (neigh_ifinfo)
 426                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 427 }
 428
 429 /**
 430  * batadv_v_ogm_metric_update - update route metric based on OGM
 431  * @bat_priv: the bat priv with all the soft interface information
 432  * @ogm2: OGM2 structure
 433  * @orig_node: Originator structure for which the OGM has been received
 434  * @neigh_node: the neigh_node through with the OGM has been received
 435  * @if_incoming: the interface where this packet was received
 436  * @if_outgoing: the interface for which the packet should be considered
 437  *
 438  * Return:
 439  *  1  if the OGM is new,
 440  *  0  if it is not new but valid,
 441  *  <0 on error (e.g. old OGM)
 442  */
 443 static int batadv_v_ogm_metric_update(struct batadv_priv *bat_priv,
 444                                       const struct batadv_ogm2_packet *ogm2,
 445                                       struct batadv_orig_node *orig_node,
 446                                       struct batadv_neigh_node *neigh_node,
 447                                       struct batadv_hard_iface *if_incoming,
 448                                       struct batadv_hard_iface *if_outgoing)
 449 {
 450         struct batadv_orig_ifinfo *orig_ifinfo;
 451         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 452         bool protection_started = false;
 453         int ret = -EINVAL;
 454         u32 path_throughput;
 455         s32 seq_diff;
 456
 457         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 458         if (!orig_ifinfo)
 459                 goto out;
 460
 461         seq_diff = ntohl(ogm2->seqno) - orig_ifinfo->last_real_seqno;
 462
 463         if (!hlist_empty(&orig_node->neigh_list) &&
 464             batadv_window_protected(bat_priv, seq_diff,
 465                                     BATADV_OGM_MAX_AGE,
 466                                     &orig_ifinfo->batman_seqno_reset,
 467                                     &protection_started)) {
 468                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 469                            "Drop packet: packet within window protection time from %pM\n",
 470                            ogm2->orig);
 471                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 472                            "Last reset: %ld, %ld\n",
 473                            orig_ifinfo->batman_seqno_reset, jiffies);
 474                 goto out;
 475         }
 476
 477         /* drop packets with old seqnos, however accept the first packet after
 478          * a host has been rebooted.
 479          */
 480         if ((seq_diff < 0) && !protection_started)
 481                 goto out;
 482
 483         neigh_node->last_seen = jiffies;
 484
 485         orig_node->last_seen = jiffies;
 486
 487         orig_ifinfo->last_real_seqno = ntohl(ogm2->seqno);
 488         orig_ifinfo->last_ttl = ogm2->ttl;
 489
 490         neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
 491         if (!neigh_ifinfo)
 492                 goto out;
 493
 494         path_throughput = batadv_v_forward_penalty(bat_priv, if_incoming,
 495                                                    if_outgoing,
 496                                                    ntohl(ogm2->throughput));
 497         neigh_ifinfo->bat_v.throughput = path_throughput;
 498         neigh_ifinfo->bat_v.last_seqno = ntohl(ogm2->seqno);
 499         neigh_ifinfo->last_ttl = ogm2->ttl;
 500
 501         if (seq_diff > 0 || protection_started)
 502                 ret = 1;
 503         else
 504                 ret = 0;
 505 out:
 506         if (orig_ifinfo)
 507                 batadv_orig_ifinfo_put(orig_ifinfo);
 508         if (neigh_ifinfo)
 509                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 510
 511         return ret;
 512 }
 513
 514 /**
 515  * batadv_v_ogm_route_update - update routes based on OGM
 516  * @bat_priv: the bat priv with all the soft interface information
 517  * @ethhdr: the Ethernet header of the OGM2
 518  * @ogm2: OGM2 structure
 519  * @orig_node: Originator structure for which the OGM has been received
 520  * @neigh_node: the neigh_node through with the OGM has been received
 521  * @if_incoming: the interface where this packet was received
 522  * @if_outgoing: the interface for which the packet should be considered
 523  *
 524  * Return: true if the packet should be forwarded, false otherwise
 525  */
 526 static bool batadv_v_ogm_route_update(struct batadv_priv *bat_priv,
 527                                       const struct ethhdr *ethhdr,
 528                                       const struct batadv_ogm2_packet *ogm2,
 529                                       struct batadv_orig_node *orig_node,
 530                                       struct batadv_neigh_node *neigh_node,
 531                                       struct batadv_hard_iface *if_incoming,
 532                                       struct batadv_hard_iface *if_outgoing)
 533 {
 534         struct batadv_neigh_node *router = NULL;
 535         struct batadv_orig_node *orig_neigh_node;
 536         struct batadv_neigh_node *orig_neigh_router = NULL;
 537         struct batadv_neigh_ifinfo *router_ifinfo = NULL, *neigh_ifinfo = NULL;
 538         u32 router_throughput, neigh_throughput;
 539         u32 router_last_seqno;
 540         u32 neigh_last_seqno;
 541         s32 neigh_seq_diff;
 542         bool forward = false;
 543
 544         orig_neigh_node = batadv_v_ogm_orig_get(bat_priv, ethhdr->h_source);
 545         if (!orig_neigh_node)
 546                 goto out;
 547
 548         orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
 549                                                    if_outgoing);
 550
 551         /* drop packet if sender is not a direct neighbor and if we
 552          * don't route towards it
 553          */
 554         router = batadv_orig_router_get(orig_node, if_outgoing);
 555         if (router && router->orig_node != orig_node && !orig_neigh_router) {
 556                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 557                            "Drop packet: OGM via unknown neighbor!\n");
 558                 goto out;
 559         }
 560
 561         /* Mark the OGM to be considered for forwarding, and update routes
 562          * if needed.
 563          */
 564         forward = true;
 565
 566         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 567                    "Searching and updating originator entry of received packet\n");
 568
 569         /* if this neighbor already is our next hop there is nothing
 570          * to change
 571          */
 572         if (router == neigh_node)
 573                 goto out;
 574
 575         /* don't consider neighbours with worse throughput.
 576          * also switch route if this seqno is BATADV_V_MAX_ORIGDIFF newer than
 577          * the last received seqno from our best next hop.
 578          */
 579         if (router) {
 580                 router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
 581                 neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 582
 583                 /* if these are not allocated, something is wrong. */
 584                 if (!router_ifinfo || !neigh_ifinfo)
 585                         goto out;
 586
 587                 neigh_last_seqno = neigh_ifinfo->bat_v.last_seqno;
 588                 router_last_seqno = router_ifinfo->bat_v.last_seqno;
 589                 neigh_seq_diff = neigh_last_seqno - router_last_seqno;
 590                 router_throughput = router_ifinfo->bat_v.throughput;
 591                 neigh_throughput = neigh_ifinfo->bat_v.throughput;
 592
 593                 if ((neigh_seq_diff < BATADV_OGM_MAX_ORIGDIFF) &&
 594                     (router_throughput >= neigh_throughput))
 595                         goto out;
 596         }
 597
 598         batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
 599 out:
 600         if (router)
 601                 batadv_neigh_node_put(router);
 602         if (orig_neigh_router)
 603                 batadv_neigh_node_put(orig_neigh_router);
 604         if (orig_neigh_node)
 605                 batadv_orig_node_put(orig_neigh_node);
 606         if (router_ifinfo)
 607                 batadv_neigh_ifinfo_put(router_ifinfo);
 608         if (neigh_ifinfo)
 609                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 610
 611         return forward;
 612 }
 613
 614 /**
 615  * batadv_v_ogm_process_per_outif - process a batman v OGM for an outgoing if
 616  * @bat_priv: the bat priv with all the soft interface information
 617  * @ethhdr: the Ethernet header of the OGM2
 618  * @ogm2: OGM2 structure
 619  * @orig_node: Originator structure for which the OGM has been received
 620  * @neigh_node: the neigh_node through with the OGM has been received
 621  * @if_incoming: the interface where this packet was received
 622  * @if_outgoing: the interface for which the packet should be considered
 623  */
 624 static void
 625 batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
 626                                const struct ethhdr *ethhdr,
 627                                const struct batadv_ogm2_packet *ogm2,
 628                                struct batadv_orig_node *orig_node,
 629                                struct batadv_neigh_node *neigh_node,
 630                                struct batadv_hard_iface *if_incoming,
 631                                struct batadv_hard_iface *if_outgoing)
 632 {
 633         int seqno_age;
 634         bool forward;
 635
 636         /* first, update the metric with according sanity checks */
 637         seqno_age = batadv_v_ogm_metric_update(bat_priv, ogm2, orig_node,
 638                                                neigh_node, if_incoming,
 639                                                if_outgoing);
 640
 641         /* outdated sequence numbers are to be discarded */
 642         if (seqno_age < 0)
 643                 return;
 644
 645         /* only unknown & newer OGMs contain TVLVs we are interested in */
 646         if ((seqno_age > 0) && (if_outgoing == BATADV_IF_DEFAULT))
 647                 batadv_tvlv_containers_process(bat_priv, true, orig_node,
 648                                                NULL, NULL,
 649                                                (unsigned char *)(ogm2 + 1),
 650                                                ntohs(ogm2->tvlv_len));
 651
 652         /* if the metric update went through, update routes if needed */
 653         forward = batadv_v_ogm_route_update(bat_priv, ethhdr, ogm2, orig_node,
 654                                             neigh_node, if_incoming,
 655                                             if_outgoing);
 656
 657         /* if the routes have been processed correctly, check and forward */
 658         if (forward)
 659                 batadv_v_ogm_forward(bat_priv, ogm2, orig_node, neigh_node,
 660                                      if_incoming, if_outgoing);
 661 }
 662
 663 /**
 664  * batadv_v_ogm_aggr_packet - checks if there is another OGM aggregated
 665  * @buff_pos: current position in the skb
 666  * @packet_len: total length of the skb
 667  * @ogm2_packet: potential OGM2 in buffer
 668  *
 669  * Return: true if there is enough space for another OGM, false otherwise.
 670  */
 671 static bool
 672 batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
 673                          const struct batadv_ogm2_packet *ogm2_packet)
 674 {
 675         int next_buff_pos = 0;
 676
 677         /* check if there is enough space for the header */
 678         next_buff_pos += buff_pos + sizeof(*ogm2_packet);
 679         if (next_buff_pos > packet_len)
 680                 return false;
 681
 682         /* check if there is enough space for the optional TVLV */
 683         next_buff_pos += ntohs(ogm2_packet->tvlv_len);
 684
 685         return (next_buff_pos <= packet_len) &&
 686                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
 687 }
 688
 689 /**
 690  * batadv_v_ogm_process - process an incoming batman v OGM
 691  * @skb: the skb containing the OGM
 692  * @ogm_offset: offset to the OGM which should be processed (for aggregates)
 693  * @if_incoming: the interface where this packet was receved
 694  */
 695 static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
 696                                  struct batadv_hard_iface *if_incoming)
 697 {
 698         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 699         struct ethhdr *ethhdr;
 700         struct batadv_orig_node *orig_node = NULL;
 701         struct batadv_hardif_neigh_node *hardif_neigh = NULL;
 702         struct batadv_neigh_node *neigh_node = NULL;
 703         struct batadv_hard_iface *hard_iface;
 704         struct batadv_ogm2_packet *ogm_packet;
 705         u32 ogm_throughput, link_throughput, path_throughput;
 706         int ret;
 707
 708         ethhdr = eth_hdr(skb);
 709         ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
 710
 711         ogm_throughput = ntohl(ogm_packet->throughput);
 712
 713         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 714                    "Received OGM2 packet via NB: %pM, IF: %s [%pM] (from OG: %pM, seqno %u, throughput %u, TTL %u, V %u, tvlv_len %u)\n",
 715                    ethhdr->h_source, if_incoming->net_dev->name,
 716                    if_incoming->net_dev->dev_addr, ogm_packet->orig,
 717                    ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
 718                    ogm_packet->version, ntohs(ogm_packet->tvlv_len));
 719
 720         if (batadv_is_my_mac(bat_priv, ogm_packet->orig)) {
 721                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 722                            "Drop packet: originator packet from ourself\n");
 723                 return;
 724         }
 725
 726         /* If the throughput metric is 0, immediately drop the packet. No need
 727          * to create orig_node / neigh_node for an unusable route.
 728          */
 729         if (ogm_throughput == 0) {
 730                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 731                            "Drop packet: originator packet with throughput metric of 0\n");
 732                 return;
 733         }
 734
 735         /* require ELP packets be to received from this neighbor first */
 736         hardif_neigh = batadv_hardif_neigh_get(if_incoming, ethhdr->h_source);
 737         if (!hardif_neigh) {
 738                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 739                            "Drop packet: OGM via unknown neighbor!\n");
 740                 goto out;
 741         }
 742
 743         orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
 744         if (!orig_node)
 745                 goto out;
 746
 747         neigh_node = batadv_neigh_node_get_or_create(orig_node, if_incoming,
 748                                                      ethhdr->h_source);
 749         if (!neigh_node)
 750                 goto out;
 751
 752         /* Update the received throughput metric to match the link
 753          * characteristic:
 754          *  - If this OGM traveled one hop so far (emitted by single hop
 755          *    neighbor) the path throughput metric equals the link throughput.
 756          *  - For OGMs traversing more than hop the path throughput metric is
 757          *    the smaller of the path throughput and the link throughput.
 758          */
 759         link_throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
 760         path_throughput = min_t(u32, link_throughput, ogm_throughput);
 761         ogm_packet->throughput = htonl(path_throughput);
 762
 763         batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet, orig_node,
 764                                        neigh_node, if_incoming,
 765                                        BATADV_IF_DEFAULT);
 766
 767         rcu_read_lock();
 768         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 769                 if (hard_iface->if_status != BATADV_IF_ACTIVE)
 770                         continue;
 771
 772                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 773                         continue;
 774
 775                 if (!kref_get_unless_zero(&hard_iface->refcount))
 776                         continue;
 777
 778                 ret = batadv_hardif_no_broadcast(hard_iface,
 779                                                  ogm_packet->orig,
 780                                                  hardif_neigh->orig);
 781
 782                 if (ret) {
 783                         char *type;
 784
 785                         switch (ret) {
 786                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 787                                 type = "no neighbor";
 788                                 break;
 789                         case BATADV_HARDIF_BCAST_DUPFWD:
 790                                 type = "single neighbor is source";
 791                                 break;
 792                         case BATADV_HARDIF_BCAST_DUPORIG:
 793                                 type = "single neighbor is originator";
 794                                 break;
 795                         default:
 796                                 type = "unknown";
 797                         }
 798
 799                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 packet from %pM on %s suppressed: %s\n",
 800                                    ogm_packet->orig, hard_iface->net_dev->name,
 801                                    type);
 802
 803                         batadv_hardif_put(hard_iface);
 804                         continue;
 805                 }
 806
 807                 batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,
 808                                                orig_node, neigh_node,
 809                                                if_incoming, hard_iface);
 810
 811                 batadv_hardif_put(hard_iface);
 812         }
 813         rcu_read_unlock();
 814 out:
 815         if (orig_node)
 816                 batadv_orig_node_put(orig_node);
 817         if (neigh_node)
 818                 batadv_neigh_node_put(neigh_node);
 819         if (hardif_neigh)
 820                 batadv_hardif_neigh_put(hardif_neigh);
 821 }
 822
 823 /**
 824  * batadv_v_ogm_packet_recv - OGM2 receiving handler
 825  * @skb: the received OGM
 826  * @if_incoming: the interface where this OGM has been received
 827  *
 828  * Return: NET_RX_SUCCESS and consume the skb on success or returns NET_RX_DROP
 829  * (without freeing the skb) on failure
 830  */
 831 int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 832                              struct batadv_hard_iface *if_incoming)
 833 {
 834         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 835         struct batadv_ogm2_packet *ogm_packet;
 836         struct ethhdr *ethhdr;
 837         int ogm_offset;
 838         u8 *packet_pos;
 839         int ret = NET_RX_DROP;
 840
 841         /* did we receive a OGM2 packet on an interface that does not have
 842          * B.A.T.M.A.N. V enabled ?
 843          */
 844         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 845                 goto free_skb;
 846
 847         if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
 848                 goto free_skb;
 849
 850         ethhdr = eth_hdr(skb);
 851         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 852                 goto free_skb;
 853
 854         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
 855         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
 856                            skb->len + ETH_HLEN);
 857
 858         ogm_offset = 0;
 859         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 860
 861         while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
 862                                         ogm_packet)) {
 863                 batadv_v_ogm_process(skb, ogm_offset, if_incoming);
 864
 865                 ogm_offset += BATADV_OGM2_HLEN;
 866                 ogm_offset += ntohs(ogm_packet->tvlv_len);
 867
 868                 packet_pos = skb->data + ogm_offset;
 869                 ogm_packet = (struct batadv_ogm2_packet *)packet_pos;
 870         }
 871
 872         ret = NET_RX_SUCCESS;
 873
 874 free_skb:
 875         if (ret == NET_RX_SUCCESS)
 876                 consume_skb(skb);
 877         else
 878                 kfree_skb(skb);
 879
 880         return ret;
 881 }
 882
 883 /**
 884  * batadv_v_ogm_init - initialise the OGM2 engine
 885  * @bat_priv: the bat priv with all the soft interface information
 886  *
 887  * Return: 0 on success or a negative error code in case of failure
 888  */
 889 int batadv_v_ogm_init(struct batadv_priv *bat_priv)
 890 {
 891         struct batadv_ogm2_packet *ogm_packet;
 892         unsigned char *ogm_buff;
 893         u32 random_seqno;
 894
 895         bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
 896         ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
 897         if (!ogm_buff)
 898                 return -ENOMEM;
 899
 900         bat_priv->bat_v.ogm_buff = ogm_buff;
 901         ogm_packet = (struct batadv_ogm2_packet *)ogm_buff;
 902         ogm_packet->packet_type = BATADV_OGM2;
 903         ogm_packet->version = BATADV_COMPAT_VERSION;
 904         ogm_packet->ttl = BATADV_TTL;
 905         ogm_packet->flags = BATADV_NO_FLAGS;
 906         ogm_packet->throughput = htonl(BATADV_THROUGHPUT_MAX_VALUE);
 907
 908         /* randomize initial seqno to avoid collision */
 909         get_random_bytes(&random_seqno, sizeof(random_seqno));
 910         atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
 911         INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
 912
 913         mutex_init(&bat_priv->bat_v.ogm_buff_mutex);
 914
 915         return 0;
 916 }
 917
 918 /**
 919  * batadv_v_ogm_free - free OGM private resources
 920  * @bat_priv: the bat priv with all the soft interface information
 921  */
 922 void batadv_v_ogm_free(struct batadv_priv *bat_priv)
 923 {
 924         cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
 925
 926         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 927
 928         kfree(bat_priv->bat_v.ogm_buff);
 929         bat_priv->bat_v.ogm_buff = NULL;
 930         bat_priv->bat_v.ogm_buff_len = 0;
 931
 932         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 933 }