net/batman-adv/bat_v_ogm.c

   1 /* Copyright (C) 2013-2016 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/netdevice.h>
  32 #include <linux/random.h>
  33 #include <linux/rculist.h>
  34 #include <linux/rcupdate.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/slab.h>
  37 #include <linux/stddef.h>
  38 #include <linux/string.h>
  39 #include <linux/types.h>
  40 #include <linux/workqueue.h>
  41
  42 #include "bat_algo.h"
  43 #include "hard-interface.h"
  44 #include "hash.h"
  45 #include "log.h"
  46 #include "originator.h"
  47 #include "packet.h"
  48 #include "routing.h"
  49 #include "send.h"
  50 #include "translation-table.h"
  51 #include "tvlv.h"
  52
  53 /**
  54  * batadv_v_ogm_orig_get - retrieve and possibly create an originator node
  55  * @bat_priv: the bat priv with all the soft interface information
  56  * @addr: the address of the originator
  57  *
  58  * Return: the orig_node corresponding to the specified address. If such object
  59  * does not exist it is allocated here. In case of allocation failure returns
  60  * NULL.
  61  */
  62 struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv,
  63                                                const u8 *addr)
  64 {
  65         struct batadv_orig_node *orig_node;
  66         int hash_added;
  67
  68         orig_node = batadv_orig_hash_find(bat_priv, addr);
  69         if (orig_node)
  70                 return orig_node;
  71
  72         orig_node = batadv_orig_node_new(bat_priv, addr);
  73         if (!orig_node)
  74                 return NULL;
  75
  76         hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
  77                                      batadv_choose_orig, orig_node,
  78                                      &orig_node->hash_entry);
  79         if (hash_added != 0) {
  80                 /* orig_node->refcounter is initialised to 2 by
  81                  * batadv_orig_node_new()
  82                  */
  83                 batadv_orig_node_put(orig_node);
  84                 batadv_orig_node_put(orig_node);
  85                 orig_node = NULL;
  86         }
  87
  88         return orig_node;
  89 }
  90
  91 /**
  92  * batadv_v_ogm_start_timer - restart the OGM sending timer
  93  * @bat_priv: the bat priv with all the soft interface information
  94  */
  95 static void batadv_v_ogm_start_timer(struct batadv_priv *bat_priv)
  96 {
  97         unsigned long msecs;
  98         /* this function may be invoked in different contexts (ogm rescheduling
  99          * or hard_iface activation), but the work timer should not be reset
 100          */
 101         if (delayed_work_pending(&bat_priv->bat_v.ogm_wq))
 102                 return;
 103
 104         msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER;
 105         msecs += prandom_u32() % (2 * BATADV_JITTER);
 106         queue_delayed_work(batadv_event_workqueue, &bat_priv->bat_v.ogm_wq,
 107                            msecs_to_jiffies(msecs));
 108 }
 109
 110 /**
 111  * batadv_v_ogm_send_to_if - send a batman ogm using a given interface
 112  * @skb: the OGM to send
 113  * @hard_iface: the interface to use to send the OGM
 114  */
 115 static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
 116                                     struct batadv_hard_iface *hard_iface)
 117 {
 118         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 119
 120         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 121                 return;
 122
 123         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
 124         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
 125                            skb->len + ETH_HLEN);
 126
 127         batadv_send_broadcast_skb(skb, hard_iface);
 128 }
 129
 130 /**
 131  * batadv_v_ogm_send - periodic worker broadcasting the own OGM
 132  * @work: work queue item
 133  */
 134 static void batadv_v_ogm_send(struct work_struct *work)
 135 {
 136         struct batadv_hard_iface *hard_iface;
 137         struct batadv_priv_bat_v *bat_v;
 138         struct batadv_priv *bat_priv;
 139         struct batadv_ogm2_packet *ogm_packet;
 140         struct sk_buff *skb, *skb_tmp;
 141         unsigned char *ogm_buff, *pkt_buff;
 142         int ogm_buff_len;
 143         u16 tvlv_len = 0;
 144
 145         bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
 146         bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
 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         pkt_buff = skb_put(skb, ogm_buff_len);
 170         memcpy(pkt_buff, 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                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 187                            "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",
 188                            ogm_packet->orig, ntohl(ogm_packet->seqno),
 189                            ntohl(ogm_packet->throughput), ogm_packet->ttl,
 190                            hard_iface->net_dev->name,
 191                            hard_iface->net_dev->dev_addr);
 192
 193                 /* this skb gets consumed by batadv_v_ogm_send_to_if() */
 194                 skb_tmp = skb_clone(skb, GFP_ATOMIC);
 195                 if (!skb_tmp) {
 196                         batadv_hardif_put(hard_iface);
 197                         break;
 198                 }
 199
 200                 batadv_v_ogm_send_to_if(skb_tmp, hard_iface);
 201                 batadv_hardif_put(hard_iface);
 202         }
 203         rcu_read_unlock();
 204
 205         consume_skb(skb);
 206
 207 reschedule:
 208         batadv_v_ogm_start_timer(bat_priv);
 209 out:
 210         return;
 211 }
 212
 213 /**
 214  * batadv_v_ogm_iface_enable - prepare an interface for B.A.T.M.A.N. V
 215  * @hard_iface: the interface to prepare
 216  *
 217  * Takes care of scheduling own OGM sending routine for this interface.
 218  *
 219  * Return: 0 on success or a negative error code otherwise
 220  */
 221 int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 222 {
 223         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 224
 225         batadv_v_ogm_start_timer(bat_priv);
 226
 227         return 0;
 228 }
 229
 230 /**
 231  * batadv_v_ogm_primary_iface_set - set a new primary interface
 232  * @primary_iface: the new primary interface
 233  */
 234 void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
 235 {
 236         struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
 237         struct batadv_ogm2_packet *ogm_packet;
 238
 239         if (!bat_priv->bat_v.ogm_buff)
 240                 return;
 241
 242         ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
 243         ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
 244 }
 245
 246 /**
 247  * batadv_v_forward_penalty - apply a penalty to the throughput metric forwarded
 248  *  with B.A.T.M.A.N. V OGMs
 249  * @bat_priv: the bat priv with all the soft interface information
 250  * @if_incoming: the interface where the OGM has been received
 251  * @if_outgoing: the interface where the OGM has to be forwarded to
 252  * @throughput: the current throughput
 253  *
 254  * Apply a penalty on the current throughput metric value based on the
 255  * characteristic of the interface where the OGM has been received. The return
 256  * value is computed as follows:
 257  * - throughput * 50%          if the incoming and outgoing interface are the
 258  *                             same WiFi interface and the throughput is above
 259  *                             1MBit/s
 260  * - throughput                if the outgoing interface is the default
 261  *                             interface (i.e. this OGM is processed for the
 262  *                             internal table and not forwarded)
 263  * - throughput * hop penalty  otherwise
 264  *
 265  * Return: the penalised throughput metric.
 266  */
 267 static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv,
 268                                     struct batadv_hard_iface *if_incoming,
 269                                     struct batadv_hard_iface *if_outgoing,
 270                                     u32 throughput)
 271 {
 272         int hop_penalty = atomic_read(&bat_priv->hop_penalty);
 273         int hop_penalty_max = BATADV_TQ_MAX_VALUE;
 274
 275         /* Don't apply hop penalty in default originator table. */
 276         if (if_outgoing == BATADV_IF_DEFAULT)
 277                 return throughput;
 278
 279         /* Forwarding on the same WiFi interface cuts the throughput in half
 280          * due to the store & forward characteristics of WIFI.
 281          * Very low throughput values are the exception.
 282          */
 283         if ((throughput > 10) &&
 284             (if_incoming == if_outgoing) &&
 285             !(if_incoming->bat_v.flags & BATADV_FULL_DUPLEX))
 286                 return throughput / 2;
 287
 288         /* hop penalty of 255 equals 100% */
 289         return throughput * (hop_penalty_max - hop_penalty) / hop_penalty_max;
 290 }
 291
 292 /**
 293  * batadv_v_ogm_forward - check conditions and forward an OGM to the given
 294  *  outgoing interface
 295  * @bat_priv: the bat priv with all the soft interface information
 296  * @ogm_received: previously received OGM to be forwarded
 297  * @orig_node: the originator which has been updated
 298  * @neigh_node: the neigh_node through with the OGM has been received
 299  * @if_incoming: the interface on which this OGM was received on
 300  * @if_outgoing: the interface to which the OGM has to be forwarded to
 301  *
 302  * Forward an OGM to an interface after having altered the throughput metric and
 303  * the TTL value contained in it. The original OGM isn't modified.
 304  */
 305 static void batadv_v_ogm_forward(struct batadv_priv *bat_priv,
 306                                  const struct batadv_ogm2_packet *ogm_received,
 307                                  struct batadv_orig_node *orig_node,
 308                                  struct batadv_neigh_node *neigh_node,
 309                                  struct batadv_hard_iface *if_incoming,
 310                                  struct batadv_hard_iface *if_outgoing)
 311 {
 312         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 313         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 314         struct batadv_neigh_node *router = NULL;
 315         struct batadv_ogm2_packet *ogm_forward;
 316         unsigned char *skb_buff;
 317         struct sk_buff *skb;
 318         size_t packet_len;
 319         u16 tvlv_len;
 320
 321         /* only forward for specific interfaces, not for the default one. */
 322         if (if_outgoing == BATADV_IF_DEFAULT)
 323                 goto out;
 324
 325         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 326         if (!orig_ifinfo)
 327                 goto out;
 328
 329         /* acquire possibly updated router */
 330         router = batadv_orig_router_get(orig_node, if_outgoing);
 331
 332         /* strict rule: forward packets coming from the best next hop only */
 333         if (neigh_node != router)
 334                 goto out;
 335
 336         /* don't forward the same seqno twice on one interface */
 337         if (orig_ifinfo->last_seqno_forwarded == ntohl(ogm_received->seqno))
 338                 goto out;
 339
 340         orig_ifinfo->last_seqno_forwarded = ntohl(ogm_received->seqno);
 341
 342         if (ogm_received->ttl <= 1) {
 343                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
 344                 goto out;
 345         }
 346
 347         neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 348         if (!neigh_ifinfo)
 349                 goto out;
 350
 351         tvlv_len = ntohs(ogm_received->tvlv_len);
 352
 353         packet_len = BATADV_OGM2_HLEN + tvlv_len;
 354         skb = netdev_alloc_skb_ip_align(if_outgoing->net_dev,
 355                                         ETH_HLEN + packet_len);
 356         if (!skb)
 357                 goto out;
 358
 359         skb_reserve(skb, ETH_HLEN);
 360         skb_buff = skb_put(skb, packet_len);
 361         memcpy(skb_buff, ogm_received, packet_len);
 362
 363         /* apply forward penalty */
 364         ogm_forward = (struct batadv_ogm2_packet *)skb_buff;
 365         ogm_forward->throughput = htonl(neigh_ifinfo->bat_v.throughput);
 366         ogm_forward->ttl--;
 367
 368         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 369                    "Forwarding OGM2 packet on %s: throughput %u, ttl %u, received via %s\n",
 370                    if_outgoing->net_dev->name, ntohl(ogm_forward->throughput),
 371                    ogm_forward->ttl, if_incoming->net_dev->name);
 372
 373         batadv_v_ogm_send_to_if(skb, if_outgoing);
 374
 375 out:
 376         if (orig_ifinfo)
 377                 batadv_orig_ifinfo_put(orig_ifinfo);
 378         if (router)
 379                 batadv_neigh_node_put(router);
 380         if (neigh_ifinfo)
 381                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 382 }
 383
 384 /**
 385  * batadv_v_ogm_metric_update - update route metric based on OGM
 386  * @bat_priv: the bat priv with all the soft interface information
 387  * @ogm2: OGM2 structure
 388  * @orig_node: Originator structure for which the OGM has been received
 389  * @neigh_node: the neigh_node through with the OGM has been received
 390  * @if_incoming: the interface where this packet was received
 391  * @if_outgoing: the interface for which the packet should be considered
 392  *
 393  * Return:
 394  *  1  if the OGM is new,
 395  *  0  if it is not new but valid,
 396  *  <0 on error (e.g. old OGM)
 397  */
 398 static int batadv_v_ogm_metric_update(struct batadv_priv *bat_priv,
 399                                       const struct batadv_ogm2_packet *ogm2,
 400                                       struct batadv_orig_node *orig_node,
 401                                       struct batadv_neigh_node *neigh_node,
 402                                       struct batadv_hard_iface *if_incoming,
 403                                       struct batadv_hard_iface *if_outgoing)
 404 {
 405         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 406         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 407         bool protection_started = false;
 408         int ret = -EINVAL;
 409         u32 path_throughput;
 410         s32 seq_diff;
 411
 412         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 413         if (!orig_ifinfo)
 414                 goto out;
 415
 416         seq_diff = ntohl(ogm2->seqno) - orig_ifinfo->last_real_seqno;
 417
 418         if (!hlist_empty(&orig_node->neigh_list) &&
 419             batadv_window_protected(bat_priv, seq_diff,
 420                                     BATADV_OGM_MAX_AGE,
 421                                     &orig_ifinfo->batman_seqno_reset,
 422                                     &protection_started)) {
 423                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 424                            "Drop packet: packet within window protection time from %pM\n",
 425                            ogm2->orig);
 426                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 427                            "Last reset: %ld, %ld\n",
 428                            orig_ifinfo->batman_seqno_reset, jiffies);
 429                 goto out;
 430         }
 431
 432         /* drop packets with old seqnos, however accept the first packet after
 433          * a host has been rebooted.
 434          */
 435         if ((seq_diff < 0) && !protection_started)
 436                 goto out;
 437
 438         neigh_node->last_seen = jiffies;
 439
 440         orig_node->last_seen = jiffies;
 441
 442         orig_ifinfo->last_real_seqno = ntohl(ogm2->seqno);
 443         orig_ifinfo->last_ttl = ogm2->ttl;
 444
 445         neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
 446         if (!neigh_ifinfo)
 447                 goto out;
 448
 449         path_throughput = batadv_v_forward_penalty(bat_priv, if_incoming,
 450                                                    if_outgoing,
 451                                                    ntohl(ogm2->throughput));
 452         neigh_ifinfo->bat_v.throughput = path_throughput;
 453         neigh_ifinfo->bat_v.last_seqno = ntohl(ogm2->seqno);
 454         neigh_ifinfo->last_ttl = ogm2->ttl;
 455
 456         if (seq_diff > 0 || protection_started)
 457                 ret = 1;
 458         else
 459                 ret = 0;
 460 out:
 461         if (orig_ifinfo)
 462                 batadv_orig_ifinfo_put(orig_ifinfo);
 463         if (neigh_ifinfo)
 464                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 465
 466         return ret;
 467 }
 468
 469 /**
 470  * batadv_v_ogm_route_update - update routes based on OGM
 471  * @bat_priv: the bat priv with all the soft interface information
 472  * @ethhdr: the Ethernet header of the OGM2
 473  * @ogm2: OGM2 structure
 474  * @orig_node: Originator structure for which the OGM has been received
 475  * @neigh_node: the neigh_node through with the OGM has been received
 476  * @if_incoming: the interface where this packet was received
 477  * @if_outgoing: the interface for which the packet should be considered
 478  *
 479  * Return: true if the packet should be forwarded, false otherwise
 480  */
 481 static bool batadv_v_ogm_route_update(struct batadv_priv *bat_priv,
 482                                       const struct ethhdr *ethhdr,
 483                                       const struct batadv_ogm2_packet *ogm2,
 484                                       struct batadv_orig_node *orig_node,
 485                                       struct batadv_neigh_node *neigh_node,
 486                                       struct batadv_hard_iface *if_incoming,
 487                                       struct batadv_hard_iface *if_outgoing)
 488 {
 489         struct batadv_neigh_node *router = NULL;
 490         struct batadv_orig_node *orig_neigh_node = NULL;
 491         struct batadv_neigh_node *orig_neigh_router = NULL;
 492         struct batadv_neigh_ifinfo *router_ifinfo = NULL, *neigh_ifinfo = NULL;
 493         u32 router_throughput, neigh_throughput;
 494         u32 router_last_seqno;
 495         u32 neigh_last_seqno;
 496         s32 neigh_seq_diff;
 497         bool forward = false;
 498
 499         orig_neigh_node = batadv_v_ogm_orig_get(bat_priv, ethhdr->h_source);
 500         if (!orig_neigh_node)
 501                 goto out;
 502
 503         orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
 504                                                    if_outgoing);
 505
 506         /* drop packet if sender is not a direct neighbor and if we
 507          * don't route towards it
 508          */
 509         router = batadv_orig_router_get(orig_node, if_outgoing);
 510         if (router && router->orig_node != orig_node && !orig_neigh_router) {
 511                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 512                            "Drop packet: OGM via unknown neighbor!\n");
 513                 goto out;
 514         }
 515
 516         /* Mark the OGM to be considered for forwarding, and update routes
 517          * if needed.
 518          */
 519         forward = true;
 520
 521         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 522                    "Searching and updating originator entry of received packet\n");
 523
 524         /* if this neighbor already is our next hop there is nothing
 525          * to change
 526          */
 527         if (router == neigh_node)
 528                 goto out;
 529
 530         /* don't consider neighbours with worse throughput.
 531          * also switch route if this seqno is BATADV_V_MAX_ORIGDIFF newer than
 532          * the last received seqno from our best next hop.
 533          */
 534         if (router) {
 535                 router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
 536                 neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 537
 538                 /* if these are not allocated, something is wrong. */
 539                 if (!router_ifinfo || !neigh_ifinfo)
 540                         goto out;
 541
 542                 neigh_last_seqno = neigh_ifinfo->bat_v.last_seqno;
 543                 router_last_seqno = router_ifinfo->bat_v.last_seqno;
 544                 neigh_seq_diff = neigh_last_seqno - router_last_seqno;
 545                 router_throughput = router_ifinfo->bat_v.throughput;
 546                 neigh_throughput = neigh_ifinfo->bat_v.throughput;
 547
 548                 if ((neigh_seq_diff < BATADV_OGM_MAX_ORIGDIFF) &&
 549                     (router_throughput >= neigh_throughput))
 550                         goto out;
 551         }
 552
 553         batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
 554 out:
 555         if (router)
 556                 batadv_neigh_node_put(router);
 557         if (orig_neigh_router)
 558                 batadv_neigh_node_put(orig_neigh_router);
 559         if (orig_neigh_node)
 560                 batadv_orig_node_put(orig_neigh_node);
 561         if (router_ifinfo)
 562                 batadv_neigh_ifinfo_put(router_ifinfo);
 563         if (neigh_ifinfo)
 564                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 565
 566         return forward;
 567 }
 568
 569 /**
 570  * batadv_v_ogm_process_per_outif - process a batman v OGM for an outgoing if
 571  * @bat_priv: the bat priv with all the soft interface information
 572  * @ethhdr: the Ethernet header of the OGM2
 573  * @ogm2: OGM2 structure
 574  * @orig_node: Originator structure for which the OGM has been received
 575  * @neigh_node: the neigh_node through with the OGM has been received
 576  * @if_incoming: the interface where this packet was received
 577  * @if_outgoing: the interface for which the packet should be considered
 578  */
 579 static void
 580 batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
 581                                const struct ethhdr *ethhdr,
 582                                const struct batadv_ogm2_packet *ogm2,
 583                                struct batadv_orig_node *orig_node,
 584                                struct batadv_neigh_node *neigh_node,
 585                                struct batadv_hard_iface *if_incoming,
 586                                struct batadv_hard_iface *if_outgoing)
 587 {
 588         int seqno_age;
 589         bool forward;
 590
 591         /* first, update the metric with according sanity checks */
 592         seqno_age = batadv_v_ogm_metric_update(bat_priv, ogm2, orig_node,
 593                                                neigh_node, if_incoming,
 594                                                if_outgoing);
 595
 596         /* outdated sequence numbers are to be discarded */
 597         if (seqno_age < 0)
 598                 return;
 599
 600         /* only unknown & newer OGMs contain TVLVs we are interested in */
 601         if ((seqno_age > 0) && (if_outgoing == BATADV_IF_DEFAULT))
 602                 batadv_tvlv_containers_process(bat_priv, true, orig_node,
 603                                                NULL, NULL,
 604                                                (unsigned char *)(ogm2 + 1),
 605                                                ntohs(ogm2->tvlv_len));
 606
 607         /* if the metric update went through, update routes if needed */
 608         forward = batadv_v_ogm_route_update(bat_priv, ethhdr, ogm2, orig_node,
 609                                             neigh_node, if_incoming,
 610                                             if_outgoing);
 611
 612         /* if the routes have been processed correctly, check and forward */
 613         if (forward)
 614                 batadv_v_ogm_forward(bat_priv, ogm2, orig_node, neigh_node,
 615                                      if_incoming, if_outgoing);
 616 }
 617
 618 /**
 619  * batadv_v_ogm_aggr_packet - checks if there is another OGM aggregated
 620  * @buff_pos: current position in the skb
 621  * @packet_len: total length of the skb
 622  * @tvlv_len: tvlv length of the previously considered OGM
 623  *
 624  * Return: true if there is enough space for another OGM, false otherwise.
 625  */
 626 static bool batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
 627                                      __be16 tvlv_len)
 628 {
 629         int next_buff_pos = 0;
 630
 631         next_buff_pos += buff_pos + BATADV_OGM2_HLEN;
 632         next_buff_pos += ntohs(tvlv_len);
 633
 634         return (next_buff_pos <= packet_len) &&
 635                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
 636 }
 637
 638 /**
 639  * batadv_v_ogm_process - process an incoming batman v OGM
 640  * @skb: the skb containing the OGM
 641  * @ogm_offset: offset to the OGM which should be processed (for aggregates)
 642  * @if_incoming: the interface where this packet was receved
 643  */
 644 static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
 645                                  struct batadv_hard_iface *if_incoming)
 646 {
 647         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 648         struct ethhdr *ethhdr;
 649         struct batadv_orig_node *orig_node = NULL;
 650         struct batadv_hardif_neigh_node *hardif_neigh = NULL;
 651         struct batadv_neigh_node *neigh_node = NULL;
 652         struct batadv_hard_iface *hard_iface;
 653         struct batadv_ogm2_packet *ogm_packet;
 654         u32 ogm_throughput, link_throughput, path_throughput;
 655
 656         ethhdr = eth_hdr(skb);
 657         ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
 658
 659         ogm_throughput = ntohl(ogm_packet->throughput);
 660
 661         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 662                    "Received OGM2 packet via NB: %pM, IF: %s [%pM] (from OG: %pM, seqno %u, troughput %u, TTL %u, V %u, tvlv_len %u)\n",
 663                    ethhdr->h_source, if_incoming->net_dev->name,
 664                    if_incoming->net_dev->dev_addr, ogm_packet->orig,
 665                    ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
 666                    ogm_packet->version, ntohs(ogm_packet->tvlv_len));
 667
 668         /* If the troughput metric is 0, immediately drop the packet. No need to
 669          * create orig_node / neigh_node for an unusable route.
 670          */
 671         if (ogm_throughput == 0) {
 672                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 673                            "Drop packet: originator packet with troughput metric of 0\n");
 674                 return;
 675         }
 676
 677         /* require ELP packets be to received from this neighbor first */
 678         hardif_neigh = batadv_hardif_neigh_get(if_incoming, ethhdr->h_source);
 679         if (!hardif_neigh) {
 680                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 681                            "Drop packet: OGM via unknown neighbor!\n");
 682                 goto out;
 683         }
 684
 685         orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
 686         if (!orig_node)
 687                 return;
 688
 689         neigh_node = batadv_neigh_node_get_or_create(orig_node, if_incoming,
 690                                                      ethhdr->h_source);
 691         if (!neigh_node)
 692                 goto out;
 693
 694         /* Update the received throughput metric to match the link
 695          * characteristic:
 696          *  - If this OGM traveled one hop so far (emitted by single hop
 697          *    neighbor) the path throughput metric equals the link throughput.
 698          *  - For OGMs traversing more than hop the path throughput metric is
 699          *    the smaller of the path throughput and the link throughput.
 700          */
 701         link_throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
 702         path_throughput = min_t(u32, link_throughput, ogm_throughput);
 703         ogm_packet->throughput = htonl(path_throughput);
 704
 705         batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet, orig_node,
 706                                        neigh_node, if_incoming,
 707                                        BATADV_IF_DEFAULT);
 708
 709         rcu_read_lock();
 710         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 711                 if (hard_iface->if_status != BATADV_IF_ACTIVE)
 712                         continue;
 713
 714                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 715                         continue;
 716
 717                 if (!kref_get_unless_zero(&hard_iface->refcount))
 718                         continue;
 719
 720                 batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,
 721                                                orig_node, neigh_node,
 722                                                if_incoming, hard_iface);
 723
 724                 batadv_hardif_put(hard_iface);
 725         }
 726         rcu_read_unlock();
 727 out:
 728         if (orig_node)
 729                 batadv_orig_node_put(orig_node);
 730         if (neigh_node)
 731                 batadv_neigh_node_put(neigh_node);
 732         if (hardif_neigh)
 733                 batadv_hardif_neigh_put(hardif_neigh);
 734 }
 735
 736 /**
 737  * batadv_v_ogm_packet_recv - OGM2 receiving handler
 738  * @skb: the received OGM
 739  * @if_incoming: the interface where this OGM has been received
 740  *
 741  * Return: NET_RX_SUCCESS and consume the skb on success or returns NET_RX_DROP
 742  * (without freeing the skb) on failure
 743  */
 744 int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 745                              struct batadv_hard_iface *if_incoming)
 746 {
 747         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 748         struct batadv_ogm2_packet *ogm_packet;
 749         struct ethhdr *ethhdr = eth_hdr(skb);
 750         int ogm_offset;
 751         u8 *packet_pos;
 752         int ret = NET_RX_DROP;
 753
 754         /* did we receive a OGM2 packet on an interface that does not have
 755          * B.A.T.M.A.N. V enabled ?
 756          */
 757         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 758                 return NET_RX_DROP;
 759
 760         if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
 761                 return NET_RX_DROP;
 762
 763         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 764                 return NET_RX_DROP;
 765
 766         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 767
 768         if (batadv_is_my_mac(bat_priv, ogm_packet->orig))
 769                 return NET_RX_DROP;
 770
 771         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
 772         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
 773                            skb->len + ETH_HLEN);
 774
 775         ogm_offset = 0;
 776         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 777
 778         while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
 779                                         ogm_packet->tvlv_len)) {
 780                 batadv_v_ogm_process(skb, ogm_offset, if_incoming);
 781
 782                 ogm_offset += BATADV_OGM2_HLEN;
 783                 ogm_offset += ntohs(ogm_packet->tvlv_len);
 784
 785                 packet_pos = skb->data + ogm_offset;
 786                 ogm_packet = (struct batadv_ogm2_packet *)packet_pos;
 787         }
 788
 789         ret = NET_RX_SUCCESS;
 790         consume_skb(skb);
 791
 792         return ret;
 793 }
 794
 795 /**
 796  * batadv_v_ogm_init - initialise the OGM2 engine
 797  * @bat_priv: the bat priv with all the soft interface information
 798  *
 799  * Return: 0 on success or a negative error code in case of failure
 800  */
 801 int batadv_v_ogm_init(struct batadv_priv *bat_priv)
 802 {
 803         struct batadv_ogm2_packet *ogm_packet;
 804         unsigned char *ogm_buff;
 805         u32 random_seqno;
 806
 807         bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
 808         ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
 809         if (!ogm_buff)
 810                 return -ENOMEM;
 811
 812         bat_priv->bat_v.ogm_buff = ogm_buff;
 813         ogm_packet = (struct batadv_ogm2_packet *)ogm_buff;
 814         ogm_packet->packet_type = BATADV_OGM2;
 815         ogm_packet->version = BATADV_COMPAT_VERSION;
 816         ogm_packet->ttl = BATADV_TTL;
 817         ogm_packet->flags = BATADV_NO_FLAGS;
 818         ogm_packet->throughput = htonl(BATADV_THROUGHPUT_MAX_VALUE);
 819
 820         /* randomize initial seqno to avoid collision */
 821         get_random_bytes(&random_seqno, sizeof(random_seqno));
 822         atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
 823         INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
 824
 825         return 0;
 826 }
 827
 828 /**
 829  * batadv_v_ogm_free - free OGM private resources
 830  * @bat_priv: the bat priv with all the soft interface information
 831  */
 832 void batadv_v_ogm_free(struct batadv_priv *bat_priv)
 833 {
 834         cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
 835
 836         kfree(bat_priv->bat_v.ogm_buff);
 837         bat_priv->bat_v.ogm_buff = NULL;
 838         bat_priv->bat_v.ogm_buff_len = 0;
 839 }