net/batman-adv/bat_v_ogm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2013-2018  B.A.T.M.A.N. contributors:
   3  *
   4  * Antonio Quartulli
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include "bat_v_ogm.h"
  20 #include "main.h"
  21
  22 #include <linux/atomic.h>
  23 #include <linux/byteorder/generic.h>
  24 #include <linux/errno.h>
  25 #include <linux/etherdevice.h>
  26 #include <linux/gfp.h>
  27 #include <linux/if_ether.h>
  28 #include <linux/jiffies.h>
  29 #include <linux/kernel.h>
  30 #include <linux/kref.h>
  31 #include <linux/list.h>
  32 #include <linux/lockdep.h>
  33 #include <linux/mutex.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/random.h>
  36 #include <linux/rculist.h>
  37 #include <linux/rcupdate.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/slab.h>
  40 #include <linux/stddef.h>
  41 #include <linux/string.h>
  42 #include <linux/types.h>
  43 #include <linux/workqueue.h>
  44 #include <uapi/linux/batadv_packet.h>
  45
  46 #include "bat_algo.h"
  47 #include "hard-interface.h"
  48 #include "hash.h"
  49 #include "log.h"
  50 #include "originator.h"
  51 #include "routing.h"
  52 #include "send.h"
  53 #include "translation-table.h"
  54 #include "tvlv.h"
  55
  56 /**
  57  * batadv_v_ogm_orig_get() - retrieve and possibly create an originator node
  58  * @bat_priv: the bat priv with all the soft interface information
  59  * @addr: the address of the originator
  60  *
  61  * Return: the orig_node corresponding to the specified address. If such object
  62  * does not exist it is allocated here. In case of allocation failure returns
  63  * NULL.
  64  */
  65 struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv,
  66                                                const u8 *addr)
  67 {
  68         struct batadv_orig_node *orig_node;
  69         int hash_added;
  70
  71         orig_node = batadv_orig_hash_find(bat_priv, addr);
  72         if (orig_node)
  73                 return orig_node;
  74
  75         orig_node = batadv_orig_node_new(bat_priv, addr);
  76         if (!orig_node)
  77                 return NULL;
  78
  79         kref_get(&orig_node->refcount);
  80         hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
  81                                      batadv_choose_orig, orig_node,
  82                                      &orig_node->hash_entry);
  83         if (hash_added != 0) {
  84                 /* remove refcnt for newly created orig_node and hash entry */
  85                 batadv_orig_node_put(orig_node);
  86                 batadv_orig_node_put(orig_node);
  87                 orig_node = NULL;
  88         }
  89
  90         return orig_node;
  91 }
  92
  93 /**
  94  * batadv_v_ogm_start_timer() - restart the OGM sending timer
  95  * @bat_priv: the bat priv with all the soft interface information
  96  */
  97 static void batadv_v_ogm_start_timer(struct batadv_priv *bat_priv)
  98 {
  99         unsigned long msecs;
 100         /* this function may be invoked in different contexts (ogm rescheduling
 101          * or hard_iface activation), but the work timer should not be reset
 102          */
 103         if (delayed_work_pending(&bat_priv->bat_v.ogm_wq))
 104                 return;
 105
 106         msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER;
 107         msecs += prandom_u32() % (2 * BATADV_JITTER);
 108         queue_delayed_work(batadv_event_workqueue, &bat_priv->bat_v.ogm_wq,
 109                            msecs_to_jiffies(msecs));
 110 }
 111
 112 /**
 113  * batadv_v_ogm_send_to_if() - send a batman ogm using a given interface
 114  * @skb: the OGM to send
 115  * @hard_iface: the interface to use to send the OGM
 116  */
 117 static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
 118                                     struct batadv_hard_iface *hard_iface)
 119 {
 120         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 121
 122         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 123                 return;
 124
 125         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
 126         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
 127                            skb->len + ETH_HLEN);
 128
 129         batadv_send_broadcast_skb(skb, hard_iface);
 130 }
 131
 132 /**
 133  * batadv_v_ogm_send_softif() - periodic worker broadcasting the own OGM
 134  * @bat_priv: the bat priv with all the soft interface information
 135  */
 136 static void batadv_v_ogm_send_softif(struct batadv_priv *bat_priv)
 137 {
 138         struct batadv_hard_iface *hard_iface;
 139         struct batadv_ogm2_packet *ogm_packet;
 140         struct sk_buff *skb, *skb_tmp;
 141         unsigned char *ogm_buff;
 142         int ogm_buff_len;
 143         u16 tvlv_len = 0;
 144         int ret;
 145
 146         lockdep_assert_held(&bat_priv->bat_v.ogm_buff_mutex);
 147
 148         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 149                 goto out;
 150
 151         ogm_buff = bat_priv->bat_v.ogm_buff;
 152         ogm_buff_len = bat_priv->bat_v.ogm_buff_len;
 153         /* tt changes have to be committed before the tvlv data is
 154          * appended as it may alter the tt tvlv container
 155          */
 156         batadv_tt_local_commit_changes(bat_priv);
 157         tvlv_len = batadv_tvlv_container_ogm_append(bat_priv, &ogm_buff,
 158                                                     &ogm_buff_len,
 159                                                     BATADV_OGM2_HLEN);
 160
 161         bat_priv->bat_v.ogm_buff = ogm_buff;
 162         bat_priv->bat_v.ogm_buff_len = ogm_buff_len;
 163
 164         skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + ogm_buff_len);
 165         if (!skb)
 166                 goto reschedule;
 167
 168         skb_reserve(skb, ETH_HLEN);
 169         skb_put_data(skb, ogm_buff, ogm_buff_len);
 170
 171         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 172         ogm_packet->seqno = htonl(atomic_read(&bat_priv->bat_v.ogm_seqno));
 173         atomic_inc(&bat_priv->bat_v.ogm_seqno);
 174         ogm_packet->tvlv_len = htons(tvlv_len);
 175
 176         /* broadcast on every interface */
 177         rcu_read_lock();
 178         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 179                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 180                         continue;
 181
 182                 if (!kref_get_unless_zero(&hard_iface->refcount))
 183                         continue;
 184
 185                 ret = batadv_hardif_no_broadcast(hard_iface, NULL, NULL);
 186                 if (ret) {
 187                         char *type;
 188
 189                         switch (ret) {
 190                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 191                                 type = "no neighbor";
 192                                 break;
 193                         case BATADV_HARDIF_BCAST_DUPFWD:
 194                                 type = "single neighbor is source";
 195                                 break;
 196                         case BATADV_HARDIF_BCAST_DUPORIG:
 197                                 type = "single neighbor is originator";
 198                                 break;
 199                         default:
 200                                 type = "unknown";
 201                         }
 202
 203                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 from ourselves on %s suppressed: %s\n",
 204                                    hard_iface->net_dev->name, type);
 205
 206                         batadv_hardif_put(hard_iface);
 207                         continue;
 208                 }
 209
 210                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 211                            "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",
 212                            ogm_packet->orig, ntohl(ogm_packet->seqno),
 213                            ntohl(ogm_packet->throughput), ogm_packet->ttl,
 214                            hard_iface->net_dev->name,
 215                            hard_iface->net_dev->dev_addr);
 216
 217                 /* this skb gets consumed by batadv_v_ogm_send_to_if() */
 218                 skb_tmp = skb_clone(skb, GFP_ATOMIC);
 219                 if (!skb_tmp) {
 220                         batadv_hardif_put(hard_iface);
 221                         break;
 222                 }
 223
 224                 batadv_v_ogm_send_to_if(skb_tmp, hard_iface);
 225                 batadv_hardif_put(hard_iface);
 226         }
 227         rcu_read_unlock();
 228
 229         consume_skb(skb);
 230
 231 reschedule:
 232         batadv_v_ogm_start_timer(bat_priv);
 233 out:
 234         return;
 235 }
 236
 237 /**
 238  * batadv_v_ogm_send() - periodic worker broadcasting the own OGM
 239  * @work: work queue item
 240  */
 241 static void batadv_v_ogm_send(struct work_struct *work)
 242 {
 243         struct batadv_priv_bat_v *bat_v;
 244         struct batadv_priv *bat_priv;
 245
 246         bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
 247         bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
 248
 249         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 250         batadv_v_ogm_send_softif(bat_priv);
 251         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 252 }
 253
 254 /**
 255  * batadv_v_ogm_iface_enable() - prepare an interface for B.A.T.M.A.N. V
 256  * @hard_iface: the interface to prepare
 257  *
 258  * Takes care of scheduling own OGM sending routine for this interface.
 259  *
 260  * Return: 0 on success or a negative error code otherwise
 261  */
 262 int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 263 {
 264         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 265
 266         batadv_v_ogm_start_timer(bat_priv);
 267
 268         return 0;
 269 }
 270
 271 /**
 272  * batadv_v_ogm_primary_iface_set() - set a new primary interface
 273  * @primary_iface: the new primary interface
 274  */
 275 void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
 276 {
 277         struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
 278         struct batadv_ogm2_packet *ogm_packet;
 279
 280         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 281         if (!bat_priv->bat_v.ogm_buff)
 282                 goto unlock;
 283
 284         ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
 285         ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
 286
 287 unlock:
 288         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 289 }
 290
 291 /**
 292  * batadv_v_forward_penalty() - apply a penalty to the throughput metric
 293  *  forwarded with B.A.T.M.A.N. V OGMs
 294  * @bat_priv: the bat priv with all the soft interface information
 295  * @if_incoming: the interface where the OGM has been received
 296  * @if_outgoing: the interface where the OGM has to be forwarded to
 297  * @throughput: the current throughput
 298  *
 299  * Apply a penalty on the current throughput metric value based on the
 300  * characteristic of the interface where the OGM has been received. The return
 301  * value is computed as follows:
 302  * - throughput * 50%          if the incoming and outgoing interface are the
 303  *                             same WiFi interface and the throughput is above
 304  *                             1MBit/s
 305  * - throughput                if the outgoing interface is the default
 306  *                             interface (i.e. this OGM is processed for the
 307  *                             internal table and not forwarded)
 308  * - throughput * hop penalty  otherwise
 309  *
 310  * Return: the penalised throughput metric.
 311  */
 312 static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv,
 313                                     struct batadv_hard_iface *if_incoming,
 314                                     struct batadv_hard_iface *if_outgoing,
 315                                     u32 throughput)
 316 {
 317         int hop_penalty = atomic_read(&bat_priv->hop_penalty);
 318         int hop_penalty_max = BATADV_TQ_MAX_VALUE;
 319
 320         /* Don't apply hop penalty in default originator table. */
 321         if (if_outgoing == BATADV_IF_DEFAULT)
 322                 return throughput;
 323
 324         /* Forwarding on the same WiFi interface cuts the throughput in half
 325          * due to the store & forward characteristics of WIFI.
 326          * Very low throughput values are the exception.
 327          */
 328         if (throughput > 10 &&
 329             if_incoming == if_outgoing &&
 330             !(if_incoming->bat_v.flags & BATADV_FULL_DUPLEX))
 331                 return throughput / 2;
 332
 333         /* hop penalty of 255 equals 100% */
 334         return throughput * (hop_penalty_max - hop_penalty) / hop_penalty_max;
 335 }
 336
 337 /**
 338  * batadv_v_ogm_forward() - check conditions and forward an OGM to the given
 339  *  outgoing interface
 340  * @bat_priv: the bat priv with all the soft interface information
 341  * @ogm_received: previously received OGM to be forwarded
 342  * @orig_node: the originator which has been updated
 343  * @neigh_node: the neigh_node through with the OGM has been received
 344  * @if_incoming: the interface on which this OGM was received on
 345  * @if_outgoing: the interface to which the OGM has to be forwarded to
 346  *
 347  * Forward an OGM to an interface after having altered the throughput metric and
 348  * the TTL value contained in it. The original OGM isn't modified.
 349  */
 350 static void batadv_v_ogm_forward(struct batadv_priv *bat_priv,
 351                                  const struct batadv_ogm2_packet *ogm_received,
 352                                  struct batadv_orig_node *orig_node,
 353                                  struct batadv_neigh_node *neigh_node,
 354                                  struct batadv_hard_iface *if_incoming,
 355                                  struct batadv_hard_iface *if_outgoing)
 356 {
 357         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 358         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 359         struct batadv_neigh_node *router = NULL;
 360         struct batadv_ogm2_packet *ogm_forward;
 361         unsigned char *skb_buff;
 362         struct sk_buff *skb;
 363         size_t packet_len;
 364         u16 tvlv_len;
 365
 366         /* only forward for specific interfaces, not for the default one. */
 367         if (if_outgoing == BATADV_IF_DEFAULT)
 368                 goto out;
 369
 370         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 371         if (!orig_ifinfo)
 372                 goto out;
 373
 374         /* acquire possibly updated router */
 375         router = batadv_orig_router_get(orig_node, if_outgoing);
 376
 377         /* strict rule: forward packets coming from the best next hop only */
 378         if (neigh_node != router)
 379                 goto out;
 380
 381         /* don't forward the same seqno twice on one interface */
 382         if (orig_ifinfo->last_seqno_forwarded == ntohl(ogm_received->seqno))
 383                 goto out;
 384
 385         orig_ifinfo->last_seqno_forwarded = ntohl(ogm_received->seqno);
 386
 387         if (ogm_received->ttl <= 1) {
 388                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
 389                 goto out;
 390         }
 391
 392         neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 393         if (!neigh_ifinfo)
 394                 goto out;
 395
 396         tvlv_len = ntohs(ogm_received->tvlv_len);
 397
 398         packet_len = BATADV_OGM2_HLEN + tvlv_len;
 399         skb = netdev_alloc_skb_ip_align(if_outgoing->net_dev,
 400                                         ETH_HLEN + packet_len);
 401         if (!skb)
 402                 goto out;
 403
 404         skb_reserve(skb, ETH_HLEN);
 405         skb_buff = skb_put_data(skb, ogm_received, packet_len);
 406
 407         /* apply forward penalty */
 408         ogm_forward = (struct batadv_ogm2_packet *)skb_buff;
 409         ogm_forward->throughput = htonl(neigh_ifinfo->bat_v.throughput);
 410         ogm_forward->ttl--;
 411
 412         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 413                    "Forwarding OGM2 packet on %s: throughput %u, ttl %u, received via %s\n",
 414                    if_outgoing->net_dev->name, ntohl(ogm_forward->throughput),
 415                    ogm_forward->ttl, if_incoming->net_dev->name);
 416
 417         batadv_v_ogm_send_to_if(skb, if_outgoing);
 418
 419 out:
 420         if (orig_ifinfo)
 421                 batadv_orig_ifinfo_put(orig_ifinfo);
 422         if (router)
 423                 batadv_neigh_node_put(router);
 424         if (neigh_ifinfo)
 425                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 426 }
 427
 428 /**
 429  * batadv_v_ogm_metric_update() - update route metric based on OGM
 430  * @bat_priv: the bat priv with all the soft interface information
 431  * @ogm2: OGM2 structure
 432  * @orig_node: Originator structure for which the OGM has been received
 433  * @neigh_node: the neigh_node through with the OGM has been received
 434  * @if_incoming: the interface where this packet was received
 435  * @if_outgoing: the interface for which the packet should be considered
 436  *
 437  * Return:
 438  *  1  if the OGM is new,
 439  *  0  if it is not new but valid,
 440  *  <0 on error (e.g. old OGM)
 441  */
 442 static int batadv_v_ogm_metric_update(struct batadv_priv *bat_priv,
 443                                       const struct batadv_ogm2_packet *ogm2,
 444                                       struct batadv_orig_node *orig_node,
 445                                       struct batadv_neigh_node *neigh_node,
 446                                       struct batadv_hard_iface *if_incoming,
 447                                       struct batadv_hard_iface *if_outgoing)
 448 {
 449         struct batadv_orig_ifinfo *orig_ifinfo;
 450         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 451         bool protection_started = false;
 452         int ret = -EINVAL;
 453         u32 path_throughput;
 454         s32 seq_diff;
 455
 456         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 457         if (!orig_ifinfo)
 458                 goto out;
 459
 460         seq_diff = ntohl(ogm2->seqno) - orig_ifinfo->last_real_seqno;
 461
 462         if (!hlist_empty(&orig_node->neigh_list) &&
 463             batadv_window_protected(bat_priv, seq_diff,
 464                                     BATADV_OGM_MAX_AGE,
 465                                     &orig_ifinfo->batman_seqno_reset,
 466                                     &protection_started)) {
 467                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 468                            "Drop packet: packet within window protection time from %pM\n",
 469                            ogm2->orig);
 470                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 471                            "Last reset: %ld, %ld\n",
 472                            orig_ifinfo->batman_seqno_reset, jiffies);
 473                 goto out;
 474         }
 475
 476         /* drop packets with old seqnos, however accept the first packet after
 477          * a host has been rebooted.
 478          */
 479         if (seq_diff < 0 && !protection_started)
 480                 goto out;
 481
 482         neigh_node->last_seen = jiffies;
 483
 484         orig_node->last_seen = jiffies;
 485
 486         orig_ifinfo->last_real_seqno = ntohl(ogm2->seqno);
 487         orig_ifinfo->last_ttl = ogm2->ttl;
 488
 489         neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
 490         if (!neigh_ifinfo)
 491                 goto out;
 492
 493         path_throughput = batadv_v_forward_penalty(bat_priv, if_incoming,
 494                                                    if_outgoing,
 495                                                    ntohl(ogm2->throughput));
 496         neigh_ifinfo->bat_v.throughput = path_throughput;
 497         neigh_ifinfo->bat_v.last_seqno = ntohl(ogm2->seqno);
 498         neigh_ifinfo->last_ttl = ogm2->ttl;
 499
 500         if (seq_diff > 0 || protection_started)
 501                 ret = 1;
 502         else
 503                 ret = 0;
 504 out:
 505         if (orig_ifinfo)
 506                 batadv_orig_ifinfo_put(orig_ifinfo);
 507         if (neigh_ifinfo)
 508                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 509
 510         return ret;
 511 }
 512
 513 /**
 514  * batadv_v_ogm_route_update() - update routes based on OGM
 515  * @bat_priv: the bat priv with all the soft interface information
 516  * @ethhdr: the Ethernet header of the OGM2
 517  * @ogm2: OGM2 structure
 518  * @orig_node: Originator structure for which the OGM has been received
 519  * @neigh_node: the neigh_node through with the OGM has been received
 520  * @if_incoming: the interface where this packet was received
 521  * @if_outgoing: the interface for which the packet should be considered
 522  *
 523  * Return: true if the packet should be forwarded, false otherwise
 524  */
 525 static bool batadv_v_ogm_route_update(struct batadv_priv *bat_priv,
 526                                       const struct ethhdr *ethhdr,
 527                                       const struct batadv_ogm2_packet *ogm2,
 528                                       struct batadv_orig_node *orig_node,
 529                                       struct batadv_neigh_node *neigh_node,
 530                                       struct batadv_hard_iface *if_incoming,
 531                                       struct batadv_hard_iface *if_outgoing)
 532 {
 533         struct batadv_neigh_node *router = NULL;
 534         struct batadv_orig_node *orig_neigh_node;
 535         struct batadv_neigh_node *orig_neigh_router = NULL;
 536         struct batadv_neigh_ifinfo *router_ifinfo = NULL, *neigh_ifinfo = NULL;
 537         u32 router_throughput, neigh_throughput;
 538         u32 router_last_seqno;
 539         u32 neigh_last_seqno;
 540         s32 neigh_seq_diff;
 541         bool forward = false;
 542
 543         orig_neigh_node = batadv_v_ogm_orig_get(bat_priv, ethhdr->h_source);
 544         if (!orig_neigh_node)
 545                 goto out;
 546
 547         orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
 548                                                    if_outgoing);
 549
 550         /* drop packet if sender is not a direct neighbor and if we
 551          * don't route towards it
 552          */
 553         router = batadv_orig_router_get(orig_node, if_outgoing);
 554         if (router && router->orig_node != orig_node && !orig_neigh_router) {
 555                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 556                            "Drop packet: OGM via unknown neighbor!\n");
 557                 goto out;
 558         }
 559
 560         /* Mark the OGM to be considered for forwarding, and update routes
 561          * if needed.
 562          */
 563         forward = true;
 564
 565         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 566                    "Searching and updating originator entry of received packet\n");
 567
 568         /* if this neighbor already is our next hop there is nothing
 569          * to change
 570          */
 571         if (router == neigh_node)
 572                 goto out;
 573
 574         /* don't consider neighbours with worse throughput.
 575          * also switch route if this seqno is BATADV_V_MAX_ORIGDIFF newer than
 576          * the last received seqno from our best next hop.
 577          */
 578         if (router) {
 579                 router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
 580                 neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 581
 582                 /* if these are not allocated, something is wrong. */
 583                 if (!router_ifinfo || !neigh_ifinfo)
 584                         goto out;
 585
 586                 neigh_last_seqno = neigh_ifinfo->bat_v.last_seqno;
 587                 router_last_seqno = router_ifinfo->bat_v.last_seqno;
 588                 neigh_seq_diff = neigh_last_seqno - router_last_seqno;
 589                 router_throughput = router_ifinfo->bat_v.throughput;
 590                 neigh_throughput = neigh_ifinfo->bat_v.throughput;
 591
 592                 if (neigh_seq_diff < BATADV_OGM_MAX_ORIGDIFF &&
 593                     router_throughput >= neigh_throughput)
 594                         goto out;
 595         }
 596
 597         batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
 598 out:
 599         if (router)
 600                 batadv_neigh_node_put(router);
 601         if (orig_neigh_router)
 602                 batadv_neigh_node_put(orig_neigh_router);
 603         if (orig_neigh_node)
 604                 batadv_orig_node_put(orig_neigh_node);
 605         if (router_ifinfo)
 606                 batadv_neigh_ifinfo_put(router_ifinfo);
 607         if (neigh_ifinfo)
 608                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 609
 610         return forward;
 611 }
 612
 613 /**
 614  * batadv_v_ogm_process_per_outif() - process a batman v OGM for an outgoing if
 615  * @bat_priv: the bat priv with all the soft interface information
 616  * @ethhdr: the Ethernet header of the OGM2
 617  * @ogm2: OGM2 structure
 618  * @orig_node: Originator structure for which the OGM has been received
 619  * @neigh_node: the neigh_node through with the OGM has been received
 620  * @if_incoming: the interface where this packet was received
 621  * @if_outgoing: the interface for which the packet should be considered
 622  */
 623 static void
 624 batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
 625                                const struct ethhdr *ethhdr,
 626                                const struct batadv_ogm2_packet *ogm2,
 627                                struct batadv_orig_node *orig_node,
 628                                struct batadv_neigh_node *neigh_node,
 629                                struct batadv_hard_iface *if_incoming,
 630                                struct batadv_hard_iface *if_outgoing)
 631 {
 632         int seqno_age;
 633         bool forward;
 634
 635         /* first, update the metric with according sanity checks */
 636         seqno_age = batadv_v_ogm_metric_update(bat_priv, ogm2, orig_node,
 637                                                neigh_node, if_incoming,
 638                                                if_outgoing);
 639
 640         /* outdated sequence numbers are to be discarded */
 641         if (seqno_age < 0)
 642                 return;
 643
 644         /* only unknown & newer OGMs contain TVLVs we are interested in */
 645         if (seqno_age > 0 && if_outgoing == BATADV_IF_DEFAULT)
 646                 batadv_tvlv_containers_process(bat_priv, true, orig_node,
 647                                                NULL, NULL,
 648                                                (unsigned char *)(ogm2 + 1),
 649                                                ntohs(ogm2->tvlv_len));
 650
 651         /* if the metric update went through, update routes if needed */
 652         forward = batadv_v_ogm_route_update(bat_priv, ethhdr, ogm2, orig_node,
 653                                             neigh_node, if_incoming,
 654                                             if_outgoing);
 655
 656         /* if the routes have been processed correctly, check and forward */
 657         if (forward)
 658                 batadv_v_ogm_forward(bat_priv, ogm2, orig_node, neigh_node,
 659                                      if_incoming, if_outgoing);
 660 }
 661
 662 /**
 663  * batadv_v_ogm_aggr_packet() - checks if there is another OGM aggregated
 664  * @buff_pos: current position in the skb
 665  * @packet_len: total length of the skb
 666  * @ogm2_packet: potential OGM2 in buffer
 667  *
 668  * Return: true if there is enough space for another OGM, false otherwise.
 669  */
 670 static bool
 671 batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
 672                          const struct batadv_ogm2_packet *ogm2_packet)
 673 {
 674         int next_buff_pos = 0;
 675
 676         /* check if there is enough space for the header */
 677         next_buff_pos += buff_pos + sizeof(*ogm2_packet);
 678         if (next_buff_pos > packet_len)
 679                 return false;
 680
 681         /* check if there is enough space for the optional TVLV */
 682         next_buff_pos += ntohs(ogm2_packet->tvlv_len);
 683
 684         return (next_buff_pos <= packet_len) &&
 685                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
 686 }
 687
 688 /**
 689  * batadv_v_ogm_process() - process an incoming batman v OGM
 690  * @skb: the skb containing the OGM
 691  * @ogm_offset: offset to the OGM which should be processed (for aggregates)
 692  * @if_incoming: the interface where this packet was receved
 693  */
 694 static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
 695                                  struct batadv_hard_iface *if_incoming)
 696 {
 697         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 698         struct ethhdr *ethhdr;
 699         struct batadv_orig_node *orig_node = NULL;
 700         struct batadv_hardif_neigh_node *hardif_neigh = NULL;
 701         struct batadv_neigh_node *neigh_node = NULL;
 702         struct batadv_hard_iface *hard_iface;
 703         struct batadv_ogm2_packet *ogm_packet;
 704         u32 ogm_throughput, link_throughput, path_throughput;
 705         int ret;
 706
 707         ethhdr = eth_hdr(skb);
 708         ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
 709
 710         ogm_throughput = ntohl(ogm_packet->throughput);
 711
 712         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 713                    "Received OGM2 packet via NB: %pM, IF: %s [%pM] (from OG: %pM, seqno %u, throughput %u, TTL %u, V %u, tvlv_len %u)\n",
 714                    ethhdr->h_source, if_incoming->net_dev->name,
 715                    if_incoming->net_dev->dev_addr, ogm_packet->orig,
 716                    ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
 717                    ogm_packet->version, ntohs(ogm_packet->tvlv_len));
 718
 719         if (batadv_is_my_mac(bat_priv, ogm_packet->orig)) {
 720                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 721                            "Drop packet: originator packet from ourself\n");
 722                 return;
 723         }
 724
 725         /* If the throughput metric is 0, immediately drop the packet. No need
 726          * to create orig_node / neigh_node for an unusable route.
 727          */
 728         if (ogm_throughput == 0) {
 729                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 730                            "Drop packet: originator packet with throughput metric of 0\n");
 731                 return;
 732         }
 733
 734         /* require ELP packets be to received from this neighbor first */
 735         hardif_neigh = batadv_hardif_neigh_get(if_incoming, ethhdr->h_source);
 736         if (!hardif_neigh) {
 737                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 738                            "Drop packet: OGM via unknown neighbor!\n");
 739                 goto out;
 740         }
 741
 742         orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
 743         if (!orig_node)
 744                 goto out;
 745
 746         neigh_node = batadv_neigh_node_get_or_create(orig_node, if_incoming,
 747                                                      ethhdr->h_source);
 748         if (!neigh_node)
 749                 goto out;
 750
 751         /* Update the received throughput metric to match the link
 752          * characteristic:
 753          *  - If this OGM traveled one hop so far (emitted by single hop
 754          *    neighbor) the path throughput metric equals the link throughput.
 755          *  - For OGMs traversing more than hop the path throughput metric is
 756          *    the smaller of the path throughput and the link throughput.
 757          */
 758         link_throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
 759         path_throughput = min_t(u32, link_throughput, ogm_throughput);
 760         ogm_packet->throughput = htonl(path_throughput);
 761
 762         batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet, orig_node,
 763                                        neigh_node, if_incoming,
 764                                        BATADV_IF_DEFAULT);
 765
 766         rcu_read_lock();
 767         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 768                 if (hard_iface->if_status != BATADV_IF_ACTIVE)
 769                         continue;
 770
 771                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 772                         continue;
 773
 774                 if (!kref_get_unless_zero(&hard_iface->refcount))
 775                         continue;
 776
 777                 ret = batadv_hardif_no_broadcast(hard_iface,
 778                                                  ogm_packet->orig,
 779                                                  hardif_neigh->orig);
 780
 781                 if (ret) {
 782                         char *type;
 783
 784                         switch (ret) {
 785                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 786                                 type = "no neighbor";
 787                                 break;
 788                         case BATADV_HARDIF_BCAST_DUPFWD:
 789                                 type = "single neighbor is source";
 790                                 break;
 791                         case BATADV_HARDIF_BCAST_DUPORIG:
 792                                 type = "single neighbor is originator";
 793                                 break;
 794                         default:
 795                                 type = "unknown";
 796                         }
 797
 798                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 packet from %pM on %s suppressed: %s\n",
 799                                    ogm_packet->orig, hard_iface->net_dev->name,
 800                                    type);
 801
 802                         batadv_hardif_put(hard_iface);
 803                         continue;
 804                 }
 805
 806                 batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,
 807                                                orig_node, neigh_node,
 808                                                if_incoming, hard_iface);
 809
 810                 batadv_hardif_put(hard_iface);
 811         }
 812         rcu_read_unlock();
 813 out:
 814         if (orig_node)
 815                 batadv_orig_node_put(orig_node);
 816         if (neigh_node)
 817                 batadv_neigh_node_put(neigh_node);
 818         if (hardif_neigh)
 819                 batadv_hardif_neigh_put(hardif_neigh);
 820 }
 821
 822 /**
 823  * batadv_v_ogm_packet_recv() - OGM2 receiving handler
 824  * @skb: the received OGM
 825  * @if_incoming: the interface where this OGM has been received
 826  *
 827  * Return: NET_RX_SUCCESS and consume the skb on success or returns NET_RX_DROP
 828  * (without freeing the skb) on failure
 829  */
 830 int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 831                              struct batadv_hard_iface *if_incoming)
 832 {
 833         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 834         struct batadv_ogm2_packet *ogm_packet;
 835         struct ethhdr *ethhdr = eth_hdr(skb);
 836         int ogm_offset;
 837         u8 *packet_pos;
 838         int ret = NET_RX_DROP;
 839
 840         /* did we receive a OGM2 packet on an interface that does not have
 841          * B.A.T.M.A.N. V enabled ?
 842          */
 843         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 844                 goto free_skb;
 845
 846         if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
 847                 goto free_skb;
 848
 849         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 850                 goto free_skb;
 851
 852         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
 853         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
 854                            skb->len + ETH_HLEN);
 855
 856         ogm_offset = 0;
 857         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 858
 859         while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
 860                                         ogm_packet)) {
 861                 batadv_v_ogm_process(skb, ogm_offset, if_incoming);
 862
 863                 ogm_offset += BATADV_OGM2_HLEN;
 864                 ogm_offset += ntohs(ogm_packet->tvlv_len);
 865
 866                 packet_pos = skb->data + ogm_offset;
 867                 ogm_packet = (struct batadv_ogm2_packet *)packet_pos;
 868         }
 869
 870         ret = NET_RX_SUCCESS;
 871
 872 free_skb:
 873         if (ret == NET_RX_SUCCESS)
 874                 consume_skb(skb);
 875         else
 876                 kfree_skb(skb);
 877
 878         return ret;
 879 }
 880
 881 /**
 882  * batadv_v_ogm_init() - initialise the OGM2 engine
 883  * @bat_priv: the bat priv with all the soft interface information
 884  *
 885  * Return: 0 on success or a negative error code in case of failure
 886  */
 887 int batadv_v_ogm_init(struct batadv_priv *bat_priv)
 888 {
 889         struct batadv_ogm2_packet *ogm_packet;
 890         unsigned char *ogm_buff;
 891         u32 random_seqno;
 892
 893         bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
 894         ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
 895         if (!ogm_buff)
 896                 return -ENOMEM;
 897
 898         bat_priv->bat_v.ogm_buff = ogm_buff;
 899         ogm_packet = (struct batadv_ogm2_packet *)ogm_buff;
 900         ogm_packet->packet_type = BATADV_OGM2;
 901         ogm_packet->version = BATADV_COMPAT_VERSION;
 902         ogm_packet->ttl = BATADV_TTL;
 903         ogm_packet->flags = BATADV_NO_FLAGS;
 904         ogm_packet->throughput = htonl(BATADV_THROUGHPUT_MAX_VALUE);
 905
 906         /* randomize initial seqno to avoid collision */
 907         get_random_bytes(&random_seqno, sizeof(random_seqno));
 908         atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
 909         INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
 910
 911         mutex_init(&bat_priv->bat_v.ogm_buff_mutex);
 912
 913         return 0;
 914 }
 915
 916 /**
 917  * batadv_v_ogm_free() - free OGM private resources
 918  * @bat_priv: the bat priv with all the soft interface information
 919  */
 920 void batadv_v_ogm_free(struct batadv_priv *bat_priv)
 921 {
 922         cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
 923
 924         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 925
 926         kfree(bat_priv->bat_v.ogm_buff);
 927         bat_priv->bat_v.ogm_buff = NULL;
 928         bat_priv->bat_v.ogm_buff_len = 0;
 929
 930         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 931 }