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                 kfree_skb(skb);
 124                 return;
 125         }
 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_send_softif() - periodic worker broadcasting the own OGM
 136  * @bat_priv: the bat priv with all the soft interface information
 137  */
 138 static void batadv_v_ogm_send_softif(struct batadv_priv *bat_priv)
 139 {
 140         struct batadv_hard_iface *hard_iface;
 141         struct batadv_ogm2_packet *ogm_packet;
 142         struct sk_buff *skb, *skb_tmp;
 143         unsigned char *ogm_buff;
 144         int ogm_buff_len;
 145         u16 tvlv_len = 0;
 146         int ret;
 147
 148         lockdep_assert_held(&bat_priv->bat_v.ogm_buff_mutex);
 149
 150         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 151                 goto out;
 152
 153         ogm_buff = bat_priv->bat_v.ogm_buff;
 154         ogm_buff_len = bat_priv->bat_v.ogm_buff_len;
 155         /* tt changes have to be committed before the tvlv data is
 156          * appended as it may alter the tt tvlv container
 157          */
 158         batadv_tt_local_commit_changes(bat_priv);
 159         tvlv_len = batadv_tvlv_container_ogm_append(bat_priv, &ogm_buff,
 160                                                     &ogm_buff_len,
 161                                                     BATADV_OGM2_HLEN);
 162
 163         bat_priv->bat_v.ogm_buff = ogm_buff;
 164         bat_priv->bat_v.ogm_buff_len = ogm_buff_len;
 165
 166         skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + ogm_buff_len);
 167         if (!skb)
 168                 goto reschedule;
 169
 170         skb_reserve(skb, ETH_HLEN);
 171         skb_put_data(skb, ogm_buff, ogm_buff_len);
 172
 173         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 174         ogm_packet->seqno = htonl(atomic_read(&bat_priv->bat_v.ogm_seqno));
 175         atomic_inc(&bat_priv->bat_v.ogm_seqno);
 176         ogm_packet->tvlv_len = htons(tvlv_len);
 177
 178         /* broadcast on every interface */
 179         rcu_read_lock();
 180         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 181                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 182                         continue;
 183
 184                 if (!kref_get_unless_zero(&hard_iface->refcount))
 185                         continue;
 186
 187                 ret = batadv_hardif_no_broadcast(hard_iface, NULL, NULL);
 188                 if (ret) {
 189                         char *type;
 190
 191                         switch (ret) {
 192                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 193                                 type = "no neighbor";
 194                                 break;
 195                         case BATADV_HARDIF_BCAST_DUPFWD:
 196                                 type = "single neighbor is source";
 197                                 break;
 198                         case BATADV_HARDIF_BCAST_DUPORIG:
 199                                 type = "single neighbor is originator";
 200                                 break;
 201                         default:
 202                                 type = "unknown";
 203                         }
 204
 205                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 from ourselves on %s suppressed: %s\n",
 206                                    hard_iface->net_dev->name, type);
 207
 208                         batadv_hardif_put(hard_iface);
 209                         continue;
 210                 }
 211
 212                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 213                            "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",
 214                            ogm_packet->orig, ntohl(ogm_packet->seqno),
 215                            ntohl(ogm_packet->throughput), ogm_packet->ttl,
 216                            hard_iface->net_dev->name,
 217                            hard_iface->net_dev->dev_addr);
 218
 219                 /* this skb gets consumed by batadv_v_ogm_send_to_if() */
 220                 skb_tmp = skb_clone(skb, GFP_ATOMIC);
 221                 if (!skb_tmp) {
 222                         batadv_hardif_put(hard_iface);
 223                         break;
 224                 }
 225
 226                 batadv_v_ogm_send_to_if(skb_tmp, hard_iface);
 227                 batadv_hardif_put(hard_iface);
 228         }
 229         rcu_read_unlock();
 230
 231         consume_skb(skb);
 232
 233 reschedule:
 234         batadv_v_ogm_start_timer(bat_priv);
 235 out:
 236         return;
 237 }
 238
 239 /**
 240  * batadv_v_ogm_send() - periodic worker broadcasting the own OGM
 241  * @work: work queue item
 242  */
 243 static void batadv_v_ogm_send(struct work_struct *work)
 244 {
 245         struct batadv_priv_bat_v *bat_v;
 246         struct batadv_priv *bat_priv;
 247
 248         bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
 249         bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
 250
 251         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 252         batadv_v_ogm_send_softif(bat_priv);
 253         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 254 }
 255
 256 /**
 257  * batadv_v_ogm_iface_enable() - prepare an interface for B.A.T.M.A.N. V
 258  * @hard_iface: the interface to prepare
 259  *
 260  * Takes care of scheduling own OGM sending routine for this interface.
 261  *
 262  * Return: 0 on success or a negative error code otherwise
 263  */
 264 int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 265 {
 266         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 267
 268         batadv_v_ogm_start_timer(bat_priv);
 269
 270         return 0;
 271 }
 272
 273 /**
 274  * batadv_v_ogm_primary_iface_set() - set a new primary interface
 275  * @primary_iface: the new primary interface
 276  */
 277 void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
 278 {
 279         struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
 280         struct batadv_ogm2_packet *ogm_packet;
 281
 282         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 283         if (!bat_priv->bat_v.ogm_buff)
 284                 goto unlock;
 285
 286         ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
 287         ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
 288
 289 unlock:
 290         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 291 }
 292
 293 /**
 294  * batadv_v_forward_penalty() - apply a penalty to the throughput metric
 295  *  forwarded with B.A.T.M.A.N. V OGMs
 296  * @bat_priv: the bat priv with all the soft interface information
 297  * @if_incoming: the interface where the OGM has been received
 298  * @if_outgoing: the interface where the OGM has to be forwarded to
 299  * @throughput: the current throughput
 300  *
 301  * Apply a penalty on the current throughput metric value based on the
 302  * characteristic of the interface where the OGM has been received. The return
 303  * value is computed as follows:
 304  * - throughput * 50%          if the incoming and outgoing interface are the
 305  *                             same WiFi interface and the throughput is above
 306  *                             1MBit/s
 307  * - throughput                if the outgoing interface is the default
 308  *                             interface (i.e. this OGM is processed for the
 309  *                             internal table and not forwarded)
 310  * - throughput * hop penalty  otherwise
 311  *
 312  * Return: the penalised throughput metric.
 313  */
 314 static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv,
 315                                     struct batadv_hard_iface *if_incoming,
 316                                     struct batadv_hard_iface *if_outgoing,
 317                                     u32 throughput)
 318 {
 319         int hop_penalty = atomic_read(&bat_priv->hop_penalty);
 320         int hop_penalty_max = BATADV_TQ_MAX_VALUE;
 321
 322         /* Don't apply hop penalty in default originator table. */
 323         if (if_outgoing == BATADV_IF_DEFAULT)
 324                 return throughput;
 325
 326         /* Forwarding on the same WiFi interface cuts the throughput in half
 327          * due to the store & forward characteristics of WIFI.
 328          * Very low throughput values are the exception.
 329          */
 330         if (throughput > 10 &&
 331             if_incoming == if_outgoing &&
 332             !(if_incoming->bat_v.flags & BATADV_FULL_DUPLEX))
 333                 return throughput / 2;
 334
 335         /* hop penalty of 255 equals 100% */
 336         return throughput * (hop_penalty_max - hop_penalty) / hop_penalty_max;
 337 }
 338
 339 /**
 340  * batadv_v_ogm_forward() - check conditions and forward an OGM to the given
 341  *  outgoing interface
 342  * @bat_priv: the bat priv with all the soft interface information
 343  * @ogm_received: previously received OGM to be forwarded
 344  * @orig_node: the originator which has been updated
 345  * @neigh_node: the neigh_node through with the OGM has been received
 346  * @if_incoming: the interface on which this OGM was received on
 347  * @if_outgoing: the interface to which the OGM has to be forwarded to
 348  *
 349  * Forward an OGM to an interface after having altered the throughput metric and
 350  * the TTL value contained in it. The original OGM isn't modified.
 351  */
 352 static void batadv_v_ogm_forward(struct batadv_priv *bat_priv,
 353                                  const struct batadv_ogm2_packet *ogm_received,
 354                                  struct batadv_orig_node *orig_node,
 355                                  struct batadv_neigh_node *neigh_node,
 356                                  struct batadv_hard_iface *if_incoming,
 357                                  struct batadv_hard_iface *if_outgoing)
 358 {
 359         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 360         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 361         struct batadv_neigh_node *router = NULL;
 362         struct batadv_ogm2_packet *ogm_forward;
 363         unsigned char *skb_buff;
 364         struct sk_buff *skb;
 365         size_t packet_len;
 366         u16 tvlv_len;
 367
 368         /* only forward for specific interfaces, not for the default one. */
 369         if (if_outgoing == BATADV_IF_DEFAULT)
 370                 goto out;
 371
 372         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 373         if (!orig_ifinfo)
 374                 goto out;
 375
 376         /* acquire possibly updated router */
 377         router = batadv_orig_router_get(orig_node, if_outgoing);
 378
 379         /* strict rule: forward packets coming from the best next hop only */
 380         if (neigh_node != router)
 381                 goto out;
 382
 383         /* don't forward the same seqno twice on one interface */
 384         if (orig_ifinfo->last_seqno_forwarded == ntohl(ogm_received->seqno))
 385                 goto out;
 386
 387         orig_ifinfo->last_seqno_forwarded = ntohl(ogm_received->seqno);
 388
 389         if (ogm_received->ttl <= 1) {
 390                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
 391                 goto out;
 392         }
 393
 394         neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 395         if (!neigh_ifinfo)
 396                 goto out;
 397
 398         tvlv_len = ntohs(ogm_received->tvlv_len);
 399
 400         packet_len = BATADV_OGM2_HLEN + tvlv_len;
 401         skb = netdev_alloc_skb_ip_align(if_outgoing->net_dev,
 402                                         ETH_HLEN + packet_len);
 403         if (!skb)
 404                 goto out;
 405
 406         skb_reserve(skb, ETH_HLEN);
 407         skb_buff = skb_put_data(skb, ogm_received, packet_len);
 408
 409         /* apply forward penalty */
 410         ogm_forward = (struct batadv_ogm2_packet *)skb_buff;
 411         ogm_forward->throughput = htonl(neigh_ifinfo->bat_v.throughput);
 412         ogm_forward->ttl--;
 413
 414         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 415                    "Forwarding OGM2 packet on %s: throughput %u, ttl %u, received via %s\n",
 416                    if_outgoing->net_dev->name, ntohl(ogm_forward->throughput),
 417                    ogm_forward->ttl, if_incoming->net_dev->name);
 418
 419         batadv_v_ogm_send_to_if(skb, if_outgoing);
 420
 421 out:
 422         if (orig_ifinfo)
 423                 batadv_orig_ifinfo_put(orig_ifinfo);
 424         if (router)
 425                 batadv_neigh_node_put(router);
 426         if (neigh_ifinfo)
 427                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 428 }
 429
 430 /**
 431  * batadv_v_ogm_metric_update() - update route metric based on OGM
 432  * @bat_priv: the bat priv with all the soft interface information
 433  * @ogm2: OGM2 structure
 434  * @orig_node: Originator structure for which the OGM has been received
 435  * @neigh_node: the neigh_node through with the OGM has been received
 436  * @if_incoming: the interface where this packet was received
 437  * @if_outgoing: the interface for which the packet should be considered
 438  *
 439  * Return:
 440  *  1  if the OGM is new,
 441  *  0  if it is not new but valid,
 442  *  <0 on error (e.g. old OGM)
 443  */
 444 static int batadv_v_ogm_metric_update(struct batadv_priv *bat_priv,
 445                                       const struct batadv_ogm2_packet *ogm2,
 446                                       struct batadv_orig_node *orig_node,
 447                                       struct batadv_neigh_node *neigh_node,
 448                                       struct batadv_hard_iface *if_incoming,
 449                                       struct batadv_hard_iface *if_outgoing)
 450 {
 451         struct batadv_orig_ifinfo *orig_ifinfo;
 452         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 453         bool protection_started = false;
 454         int ret = -EINVAL;
 455         u32 path_throughput;
 456         s32 seq_diff;
 457
 458         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 459         if (!orig_ifinfo)
 460                 goto out;
 461
 462         seq_diff = ntohl(ogm2->seqno) - orig_ifinfo->last_real_seqno;
 463
 464         if (!hlist_empty(&orig_node->neigh_list) &&
 465             batadv_window_protected(bat_priv, seq_diff,
 466                                     BATADV_OGM_MAX_AGE,
 467                                     &orig_ifinfo->batman_seqno_reset,
 468                                     &protection_started)) {
 469                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 470                            "Drop packet: packet within window protection time from %pM\n",
 471                            ogm2->orig);
 472                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 473                            "Last reset: %ld, %ld\n",
 474                            orig_ifinfo->batman_seqno_reset, jiffies);
 475                 goto out;
 476         }
 477
 478         /* drop packets with old seqnos, however accept the first packet after
 479          * a host has been rebooted.
 480          */
 481         if (seq_diff < 0 && !protection_started)
 482                 goto out;
 483
 484         neigh_node->last_seen = jiffies;
 485
 486         orig_node->last_seen = jiffies;
 487
 488         orig_ifinfo->last_real_seqno = ntohl(ogm2->seqno);
 489         orig_ifinfo->last_ttl = ogm2->ttl;
 490
 491         neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
 492         if (!neigh_ifinfo)
 493                 goto out;
 494
 495         path_throughput = batadv_v_forward_penalty(bat_priv, if_incoming,
 496                                                    if_outgoing,
 497                                                    ntohl(ogm2->throughput));
 498         neigh_ifinfo->bat_v.throughput = path_throughput;
 499         neigh_ifinfo->bat_v.last_seqno = ntohl(ogm2->seqno);
 500         neigh_ifinfo->last_ttl = ogm2->ttl;
 501
 502         if (seq_diff > 0 || protection_started)
 503                 ret = 1;
 504         else
 505                 ret = 0;
 506 out:
 507         if (orig_ifinfo)
 508                 batadv_orig_ifinfo_put(orig_ifinfo);
 509         if (neigh_ifinfo)
 510                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 511
 512         return ret;
 513 }
 514
 515 /**
 516  * batadv_v_ogm_route_update() - update routes based on OGM
 517  * @bat_priv: the bat priv with all the soft interface information
 518  * @ethhdr: the Ethernet header of the OGM2
 519  * @ogm2: OGM2 structure
 520  * @orig_node: Originator structure for which the OGM has been received
 521  * @neigh_node: the neigh_node through with the OGM has been received
 522  * @if_incoming: the interface where this packet was received
 523  * @if_outgoing: the interface for which the packet should be considered
 524  *
 525  * Return: true if the packet should be forwarded, false otherwise
 526  */
 527 static bool batadv_v_ogm_route_update(struct batadv_priv *bat_priv,
 528                                       const struct ethhdr *ethhdr,
 529                                       const struct batadv_ogm2_packet *ogm2,
 530                                       struct batadv_orig_node *orig_node,
 531                                       struct batadv_neigh_node *neigh_node,
 532                                       struct batadv_hard_iface *if_incoming,
 533                                       struct batadv_hard_iface *if_outgoing)
 534 {
 535         struct batadv_neigh_node *router = NULL;
 536         struct batadv_orig_node *orig_neigh_node;
 537         struct batadv_neigh_node *orig_neigh_router = NULL;
 538         struct batadv_neigh_ifinfo *router_ifinfo = NULL, *neigh_ifinfo = NULL;
 539         u32 router_throughput, neigh_throughput;
 540         u32 router_last_seqno;
 541         u32 neigh_last_seqno;
 542         s32 neigh_seq_diff;
 543         bool forward = false;
 544
 545         orig_neigh_node = batadv_v_ogm_orig_get(bat_priv, ethhdr->h_source);
 546         if (!orig_neigh_node)
 547                 goto out;
 548
 549         orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
 550                                                    if_outgoing);
 551
 552         /* drop packet if sender is not a direct neighbor and if we
 553          * don't route towards it
 554          */
 555         router = batadv_orig_router_get(orig_node, if_outgoing);
 556         if (router && router->orig_node != orig_node && !orig_neigh_router) {
 557                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 558                            "Drop packet: OGM via unknown neighbor!\n");
 559                 goto out;
 560         }
 561
 562         /* Mark the OGM to be considered for forwarding, and update routes
 563          * if needed.
 564          */
 565         forward = true;
 566
 567         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 568                    "Searching and updating originator entry of received packet\n");
 569
 570         /* if this neighbor already is our next hop there is nothing
 571          * to change
 572          */
 573         if (router == neigh_node)
 574                 goto out;
 575
 576         /* don't consider neighbours with worse throughput.
 577          * also switch route if this seqno is BATADV_V_MAX_ORIGDIFF newer than
 578          * the last received seqno from our best next hop.
 579          */
 580         if (router) {
 581                 router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
 582                 neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 583
 584                 /* if these are not allocated, something is wrong. */
 585                 if (!router_ifinfo || !neigh_ifinfo)
 586                         goto out;
 587
 588                 neigh_last_seqno = neigh_ifinfo->bat_v.last_seqno;
 589                 router_last_seqno = router_ifinfo->bat_v.last_seqno;
 590                 neigh_seq_diff = neigh_last_seqno - router_last_seqno;
 591                 router_throughput = router_ifinfo->bat_v.throughput;
 592                 neigh_throughput = neigh_ifinfo->bat_v.throughput;
 593
 594                 if (neigh_seq_diff < BATADV_OGM_MAX_ORIGDIFF &&
 595                     router_throughput >= neigh_throughput)
 596                         goto out;
 597         }
 598
 599         batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
 600 out:
 601         if (router)
 602                 batadv_neigh_node_put(router);
 603         if (orig_neigh_router)
 604                 batadv_neigh_node_put(orig_neigh_router);
 605         if (orig_neigh_node)
 606                 batadv_orig_node_put(orig_neigh_node);
 607         if (router_ifinfo)
 608                 batadv_neigh_ifinfo_put(router_ifinfo);
 609         if (neigh_ifinfo)
 610                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 611
 612         return forward;
 613 }
 614
 615 /**
 616  * batadv_v_ogm_process_per_outif() - process a batman v OGM for an outgoing if
 617  * @bat_priv: the bat priv with all the soft interface information
 618  * @ethhdr: the Ethernet header of the OGM2
 619  * @ogm2: OGM2 structure
 620  * @orig_node: Originator structure for which the OGM has been received
 621  * @neigh_node: the neigh_node through with the OGM has been received
 622  * @if_incoming: the interface where this packet was received
 623  * @if_outgoing: the interface for which the packet should be considered
 624  */
 625 static void
 626 batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
 627                                const struct ethhdr *ethhdr,
 628                                const struct batadv_ogm2_packet *ogm2,
 629                                struct batadv_orig_node *orig_node,
 630                                struct batadv_neigh_node *neigh_node,
 631                                struct batadv_hard_iface *if_incoming,
 632                                struct batadv_hard_iface *if_outgoing)
 633 {
 634         int seqno_age;
 635         bool forward;
 636
 637         /* first, update the metric with according sanity checks */
 638         seqno_age = batadv_v_ogm_metric_update(bat_priv, ogm2, orig_node,
 639                                                neigh_node, if_incoming,
 640                                                if_outgoing);
 641
 642         /* outdated sequence numbers are to be discarded */
 643         if (seqno_age < 0)
 644                 return;
 645
 646         /* only unknown & newer OGMs contain TVLVs we are interested in */
 647         if (seqno_age > 0 && if_outgoing == BATADV_IF_DEFAULT)
 648                 batadv_tvlv_containers_process(bat_priv, true, orig_node,
 649                                                NULL, NULL,
 650                                                (unsigned char *)(ogm2 + 1),
 651                                                ntohs(ogm2->tvlv_len));
 652
 653         /* if the metric update went through, update routes if needed */
 654         forward = batadv_v_ogm_route_update(bat_priv, ethhdr, ogm2, orig_node,
 655                                             neigh_node, if_incoming,
 656                                             if_outgoing);
 657
 658         /* if the routes have been processed correctly, check and forward */
 659         if (forward)
 660                 batadv_v_ogm_forward(bat_priv, ogm2, orig_node, neigh_node,
 661                                      if_incoming, if_outgoing);
 662 }
 663
 664 /**
 665  * batadv_v_ogm_aggr_packet() - checks if there is another OGM aggregated
 666  * @buff_pos: current position in the skb
 667  * @packet_len: total length of the skb
 668  * @ogm2_packet: potential OGM2 in buffer
 669  *
 670  * Return: true if there is enough space for another OGM, false otherwise.
 671  */
 672 static bool
 673 batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
 674                          const struct batadv_ogm2_packet *ogm2_packet)
 675 {
 676         int next_buff_pos = 0;
 677
 678         /* check if there is enough space for the header */
 679         next_buff_pos += buff_pos + sizeof(*ogm2_packet);
 680         if (next_buff_pos > packet_len)
 681                 return false;
 682
 683         /* check if there is enough space for the optional TVLV */
 684         next_buff_pos += ntohs(ogm2_packet->tvlv_len);
 685
 686         return (next_buff_pos <= packet_len) &&
 687                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
 688 }
 689
 690 /**
 691  * batadv_v_ogm_process() - process an incoming batman v OGM
 692  * @skb: the skb containing the OGM
 693  * @ogm_offset: offset to the OGM which should be processed (for aggregates)
 694  * @if_incoming: the interface where this packet was receved
 695  */
 696 static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
 697                                  struct batadv_hard_iface *if_incoming)
 698 {
 699         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 700         struct ethhdr *ethhdr;
 701         struct batadv_orig_node *orig_node = NULL;
 702         struct batadv_hardif_neigh_node *hardif_neigh = NULL;
 703         struct batadv_neigh_node *neigh_node = NULL;
 704         struct batadv_hard_iface *hard_iface;
 705         struct batadv_ogm2_packet *ogm_packet;
 706         u32 ogm_throughput, link_throughput, path_throughput;
 707         int ret;
 708
 709         ethhdr = eth_hdr(skb);
 710         ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
 711
 712         ogm_throughput = ntohl(ogm_packet->throughput);
 713
 714         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 715                    "Received OGM2 packet via NB: %pM, IF: %s [%pM] (from OG: %pM, seqno %u, throughput %u, TTL %u, V %u, tvlv_len %u)\n",
 716                    ethhdr->h_source, if_incoming->net_dev->name,
 717                    if_incoming->net_dev->dev_addr, ogm_packet->orig,
 718                    ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
 719                    ogm_packet->version, ntohs(ogm_packet->tvlv_len));
 720
 721         if (batadv_is_my_mac(bat_priv, ogm_packet->orig)) {
 722                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 723                            "Drop packet: originator packet from ourself\n");
 724                 return;
 725         }
 726
 727         /* If the throughput metric is 0, immediately drop the packet. No need
 728          * to create orig_node / neigh_node for an unusable route.
 729          */
 730         if (ogm_throughput == 0) {
 731                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 732                            "Drop packet: originator packet with throughput metric of 0\n");
 733                 return;
 734         }
 735
 736         /* require ELP packets be to received from this neighbor first */
 737         hardif_neigh = batadv_hardif_neigh_get(if_incoming, ethhdr->h_source);
 738         if (!hardif_neigh) {
 739                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 740                            "Drop packet: OGM via unknown neighbor!\n");
 741                 goto out;
 742         }
 743
 744         orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
 745         if (!orig_node)
 746                 goto out;
 747
 748         neigh_node = batadv_neigh_node_get_or_create(orig_node, if_incoming,
 749                                                      ethhdr->h_source);
 750         if (!neigh_node)
 751                 goto out;
 752
 753         /* Update the received throughput metric to match the link
 754          * characteristic:
 755          *  - If this OGM traveled one hop so far (emitted by single hop
 756          *    neighbor) the path throughput metric equals the link throughput.
 757          *  - For OGMs traversing more than hop the path throughput metric is
 758          *    the smaller of the path throughput and the link throughput.
 759          */
 760         link_throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
 761         path_throughput = min_t(u32, link_throughput, ogm_throughput);
 762         ogm_packet->throughput = htonl(path_throughput);
 763
 764         batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet, orig_node,
 765                                        neigh_node, if_incoming,
 766                                        BATADV_IF_DEFAULT);
 767
 768         rcu_read_lock();
 769         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 770                 if (hard_iface->if_status != BATADV_IF_ACTIVE)
 771                         continue;
 772
 773                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 774                         continue;
 775
 776                 if (!kref_get_unless_zero(&hard_iface->refcount))
 777                         continue;
 778
 779                 ret = batadv_hardif_no_broadcast(hard_iface,
 780                                                  ogm_packet->orig,
 781                                                  hardif_neigh->orig);
 782
 783                 if (ret) {
 784                         char *type;
 785
 786                         switch (ret) {
 787                         case BATADV_HARDIF_BCAST_NORECIPIENT:
 788                                 type = "no neighbor";
 789                                 break;
 790                         case BATADV_HARDIF_BCAST_DUPFWD:
 791                                 type = "single neighbor is source";
 792                                 break;
 793                         case BATADV_HARDIF_BCAST_DUPORIG:
 794                                 type = "single neighbor is originator";
 795                                 break;
 796                         default:
 797                                 type = "unknown";
 798                         }
 799
 800                         batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "OGM2 packet from %pM on %s suppressed: %s\n",
 801                                    ogm_packet->orig, hard_iface->net_dev->name,
 802                                    type);
 803
 804                         batadv_hardif_put(hard_iface);
 805                         continue;
 806                 }
 807
 808                 batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,
 809                                                orig_node, neigh_node,
 810                                                if_incoming, hard_iface);
 811
 812                 batadv_hardif_put(hard_iface);
 813         }
 814         rcu_read_unlock();
 815 out:
 816         if (orig_node)
 817                 batadv_orig_node_put(orig_node);
 818         if (neigh_node)
 819                 batadv_neigh_node_put(neigh_node);
 820         if (hardif_neigh)
 821                 batadv_hardif_neigh_put(hardif_neigh);
 822 }
 823
 824 /**
 825  * batadv_v_ogm_packet_recv() - OGM2 receiving handler
 826  * @skb: the received OGM
 827  * @if_incoming: the interface where this OGM has been received
 828  *
 829  * Return: NET_RX_SUCCESS and consume the skb on success or returns NET_RX_DROP
 830  * (without freeing the skb) on failure
 831  */
 832 int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 833                              struct batadv_hard_iface *if_incoming)
 834 {
 835         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 836         struct batadv_ogm2_packet *ogm_packet;
 837         struct ethhdr *ethhdr;
 838         int ogm_offset;
 839         u8 *packet_pos;
 840         int ret = NET_RX_DROP;
 841
 842         /* did we receive a OGM2 packet on an interface that does not have
 843          * B.A.T.M.A.N. V enabled ?
 844          */
 845         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 846                 goto free_skb;
 847
 848         if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
 849                 goto free_skb;
 850
 851         ethhdr = eth_hdr(skb);
 852         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 853                 goto free_skb;
 854
 855         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
 856         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
 857                            skb->len + ETH_HLEN);
 858
 859         ogm_offset = 0;
 860         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 861
 862         while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
 863                                         ogm_packet)) {
 864                 batadv_v_ogm_process(skb, ogm_offset, if_incoming);
 865
 866                 ogm_offset += BATADV_OGM2_HLEN;
 867                 ogm_offset += ntohs(ogm_packet->tvlv_len);
 868
 869                 packet_pos = skb->data + ogm_offset;
 870                 ogm_packet = (struct batadv_ogm2_packet *)packet_pos;
 871         }
 872
 873         ret = NET_RX_SUCCESS;
 874
 875 free_skb:
 876         if (ret == NET_RX_SUCCESS)
 877                 consume_skb(skb);
 878         else
 879                 kfree_skb(skb);
 880
 881         return ret;
 882 }
 883
 884 /**
 885  * batadv_v_ogm_init() - initialise the OGM2 engine
 886  * @bat_priv: the bat priv with all the soft interface information
 887  *
 888  * Return: 0 on success or a negative error code in case of failure
 889  */
 890 int batadv_v_ogm_init(struct batadv_priv *bat_priv)
 891 {
 892         struct batadv_ogm2_packet *ogm_packet;
 893         unsigned char *ogm_buff;
 894         u32 random_seqno;
 895
 896         bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
 897         ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
 898         if (!ogm_buff)
 899                 return -ENOMEM;
 900
 901         bat_priv->bat_v.ogm_buff = ogm_buff;
 902         ogm_packet = (struct batadv_ogm2_packet *)ogm_buff;
 903         ogm_packet->packet_type = BATADV_OGM2;
 904         ogm_packet->version = BATADV_COMPAT_VERSION;
 905         ogm_packet->ttl = BATADV_TTL;
 906         ogm_packet->flags = BATADV_NO_FLAGS;
 907         ogm_packet->throughput = htonl(BATADV_THROUGHPUT_MAX_VALUE);
 908
 909         /* randomize initial seqno to avoid collision */
 910         get_random_bytes(&random_seqno, sizeof(random_seqno));
 911         atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
 912         INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
 913
 914         mutex_init(&bat_priv->bat_v.ogm_buff_mutex);
 915
 916         return 0;
 917 }
 918
 919 /**
 920  * batadv_v_ogm_free() - free OGM private resources
 921  * @bat_priv: the bat priv with all the soft interface information
 922  */
 923 void batadv_v_ogm_free(struct batadv_priv *bat_priv)
 924 {
 925         cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
 926
 927         mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
 928
 929         kfree(bat_priv->bat_v.ogm_buff);
 930         bat_priv->bat_v.ogm_buff = NULL;
 931         bat_priv->bat_v.ogm_buff_len = 0;
 932
 933         mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 934 }