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 "hard-interface.h"
  43 #include "hash.h"
  44 #include "originator.h"
  45 #include "packet.h"
  46 #include "routing.h"
  47 #include "send.h"
  48 #include "translation-table.h"
  49
  50 /**
  51  * batadv_v_ogm_orig_get - retrieve and possibly create an originator node
  52  * @bat_priv: the bat priv with all the soft interface information
  53  * @addr: the address of the originator
  54  *
  55  * Return: the orig_node corresponding to the specified address. If such object
  56  * does not exist it is allocated here. In case of allocation failure returns
  57  * NULL.
  58  */
  59 struct batadv_orig_node *batadv_v_ogm_orig_get(struct batadv_priv *bat_priv,
  60                                                const u8 *addr)
  61 {
  62         struct batadv_orig_node *orig_node;
  63         int hash_added;
  64
  65         orig_node = batadv_orig_hash_find(bat_priv, addr);
  66         if (orig_node)
  67                 return orig_node;
  68
  69         orig_node = batadv_orig_node_new(bat_priv, addr);
  70         if (!orig_node)
  71                 return NULL;
  72
  73         hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
  74                                      batadv_choose_orig, orig_node,
  75                                      &orig_node->hash_entry);
  76         if (hash_added != 0) {
  77                 /* orig_node->refcounter is initialised to 2 by
  78                  * batadv_orig_node_new()
  79                  */
  80                 batadv_orig_node_put(orig_node);
  81                 batadv_orig_node_put(orig_node);
  82                 orig_node = NULL;
  83         }
  84
  85         return orig_node;
  86 }
  87
  88 /**
  89  * batadv_v_ogm_start_timer - restart the OGM sending timer
  90  * @bat_priv: the bat priv with all the soft interface information
  91  */
  92 static void batadv_v_ogm_start_timer(struct batadv_priv *bat_priv)
  93 {
  94         unsigned long msecs;
  95         /* this function may be invoked in different contexts (ogm rescheduling
  96          * or hard_iface activation), but the work timer should not be reset
  97          */
  98         if (delayed_work_pending(&bat_priv->bat_v.ogm_wq))
  99                 return;
 100
 101         msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER;
 102         msecs += prandom_u32() % (2 * BATADV_JITTER);
 103         queue_delayed_work(batadv_event_workqueue, &bat_priv->bat_v.ogm_wq,
 104                            msecs_to_jiffies(msecs));
 105 }
 106
 107 /**
 108  * batadv_v_ogm_send_to_if - send a batman ogm using a given interface
 109  * @skb: the OGM to send
 110  * @hard_iface: the interface to use to send the OGM
 111  */
 112 static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
 113                                     struct batadv_hard_iface *hard_iface)
 114 {
 115         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 116
 117         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 118                 return;
 119
 120         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
 121         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
 122                            skb->len + ETH_HLEN);
 123
 124         batadv_send_broadcast_skb(skb, hard_iface);
 125 }
 126
 127 /**
 128  * batadv_v_ogm_send - periodic worker broadcasting the own OGM
 129  * @work: work queue item
 130  */
 131 static void batadv_v_ogm_send(struct work_struct *work)
 132 {
 133         struct batadv_hard_iface *hard_iface;
 134         struct batadv_priv_bat_v *bat_v;
 135         struct batadv_priv *bat_priv;
 136         struct batadv_ogm2_packet *ogm_packet;
 137         struct sk_buff *skb, *skb_tmp;
 138         unsigned char *ogm_buff, *pkt_buff;
 139         int ogm_buff_len;
 140         u16 tvlv_len = 0;
 141
 142         bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
 143         bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
 144
 145         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 146                 goto out;
 147
 148         ogm_buff = bat_priv->bat_v.ogm_buff;
 149         ogm_buff_len = bat_priv->bat_v.ogm_buff_len;
 150         /* tt changes have to be committed before the tvlv data is
 151          * appended as it may alter the tt tvlv container
 152          */
 153         batadv_tt_local_commit_changes(bat_priv);
 154         tvlv_len = batadv_tvlv_container_ogm_append(bat_priv, &ogm_buff,
 155                                                     &ogm_buff_len,
 156                                                     BATADV_OGM2_HLEN);
 157
 158         bat_priv->bat_v.ogm_buff = ogm_buff;
 159         bat_priv->bat_v.ogm_buff_len = ogm_buff_len;
 160
 161         skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + ogm_buff_len);
 162         if (!skb)
 163                 goto reschedule;
 164
 165         skb_reserve(skb, ETH_HLEN);
 166         pkt_buff = skb_put(skb, ogm_buff_len);
 167         memcpy(pkt_buff, ogm_buff, ogm_buff_len);
 168
 169         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 170         ogm_packet->seqno = htonl(atomic_read(&bat_priv->bat_v.ogm_seqno));
 171         atomic_inc(&bat_priv->bat_v.ogm_seqno);
 172         ogm_packet->tvlv_len = htons(tvlv_len);
 173
 174         /* broadcast on every interface */
 175         rcu_read_lock();
 176         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 177                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 178                         continue;
 179
 180                 if (!kref_get_unless_zero(&hard_iface->refcount))
 181                         continue;
 182
 183                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 184                            "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",
 185                            ogm_packet->orig, ntohl(ogm_packet->seqno),
 186                            ntohl(ogm_packet->throughput), ogm_packet->ttl,
 187                            hard_iface->net_dev->name,
 188                            hard_iface->net_dev->dev_addr);
 189
 190                 /* this skb gets consumed by batadv_v_ogm_send_to_if() */
 191                 skb_tmp = skb_clone(skb, GFP_ATOMIC);
 192                 if (!skb_tmp) {
 193                         batadv_hardif_put(hard_iface);
 194                         break;
 195                 }
 196
 197                 batadv_v_ogm_send_to_if(skb_tmp, hard_iface);
 198                 batadv_hardif_put(hard_iface);
 199         }
 200         rcu_read_unlock();
 201
 202         consume_skb(skb);
 203
 204 reschedule:
 205         batadv_v_ogm_start_timer(bat_priv);
 206 out:
 207         return;
 208 }
 209
 210 /**
 211  * batadv_v_ogm_iface_enable - prepare an interface for B.A.T.M.A.N. V
 212  * @hard_iface: the interface to prepare
 213  *
 214  * Takes care of scheduling own OGM sending routine for this interface.
 215  *
 216  * Return: 0 on success or a negative error code otherwise
 217  */
 218 int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 219 {
 220         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 221
 222         batadv_v_ogm_start_timer(bat_priv);
 223
 224         return 0;
 225 }
 226
 227 /**
 228  * batadv_v_ogm_primary_iface_set - set a new primary interface
 229  * @primary_iface: the new primary interface
 230  */
 231 void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
 232 {
 233         struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
 234         struct batadv_ogm2_packet *ogm_packet;
 235
 236         if (!bat_priv->bat_v.ogm_buff)
 237                 return;
 238
 239         ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
 240         ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
 241 }
 242
 243 /**
 244  * batadv_v_forward_penalty - apply a penalty to the throughput metric forwarded
 245  *  with B.A.T.M.A.N. V OGMs
 246  * @bat_priv: the bat priv with all the soft interface information
 247  * @if_incoming: the interface where the OGM has been received
 248  * @if_outgoing: the interface where the OGM has to be forwarded to
 249  * @throughput: the current throughput
 250  *
 251  * Apply a penalty on the current throughput metric value based on the
 252  * characteristic of the interface where the OGM has been received. The return
 253  * value is computed as follows:
 254  * - throughput * 50%          if the incoming and outgoing interface are the
 255  *                             same WiFi interface and the throughput is above
 256  *                             1MBit/s
 257  * - throughput                if the outgoing interface is the default
 258  *                             interface (i.e. this OGM is processed for the
 259  *                             internal table and not forwarded)
 260  * - throughput * hop penalty  otherwise
 261  *
 262  * Return: the penalised throughput metric.
 263  */
 264 static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv,
 265                                     struct batadv_hard_iface *if_incoming,
 266                                     struct batadv_hard_iface *if_outgoing,
 267                                     u32 throughput)
 268 {
 269         int hop_penalty = atomic_read(&bat_priv->hop_penalty);
 270         int hop_penalty_max = BATADV_TQ_MAX_VALUE;
 271
 272         /* Don't apply hop penalty in default originator table. */
 273         if (if_outgoing == BATADV_IF_DEFAULT)
 274                 return throughput;
 275
 276         /* Forwarding on the same WiFi interface cuts the throughput in half
 277          * due to the store & forward characteristics of WIFI.
 278          * Very low throughput values are the exception.
 279          */
 280         if ((throughput > 10) &&
 281             (if_incoming == if_outgoing) &&
 282             !(if_incoming->bat_v.flags & BATADV_FULL_DUPLEX))
 283                 return throughput / 2;
 284
 285         /* hop penalty of 255 equals 100% */
 286         return throughput * (hop_penalty_max - hop_penalty) / hop_penalty_max;
 287 }
 288
 289 /**
 290  * batadv_v_ogm_forward - check conditions and forward an OGM to the given
 291  *  outgoing interface
 292  * @bat_priv: the bat priv with all the soft interface information
 293  * @ogm_received: previously received OGM to be forwarded
 294  * @orig_node: the originator which has been updated
 295  * @neigh_node: the neigh_node through with the OGM has been received
 296  * @if_incoming: the interface on which this OGM was received on
 297  * @if_outgoing: the interface to which the OGM has to be forwarded to
 298  *
 299  * Forward an OGM to an interface after having altered the throughput metric and
 300  * the TTL value contained in it. The original OGM isn't modified.
 301  */
 302 static void batadv_v_ogm_forward(struct batadv_priv *bat_priv,
 303                                  const struct batadv_ogm2_packet *ogm_received,
 304                                  struct batadv_orig_node *orig_node,
 305                                  struct batadv_neigh_node *neigh_node,
 306                                  struct batadv_hard_iface *if_incoming,
 307                                  struct batadv_hard_iface *if_outgoing)
 308 {
 309         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 310         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 311         struct batadv_neigh_node *router = NULL;
 312         struct batadv_ogm2_packet *ogm_forward;
 313         unsigned char *skb_buff;
 314         struct sk_buff *skb;
 315         size_t packet_len;
 316         u16 tvlv_len;
 317
 318         /* only forward for specific interfaces, not for the default one. */
 319         if (if_outgoing == BATADV_IF_DEFAULT)
 320                 goto out;
 321
 322         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 323         if (!orig_ifinfo)
 324                 goto out;
 325
 326         /* acquire possibly updated router */
 327         router = batadv_orig_router_get(orig_node, if_outgoing);
 328
 329         /* strict rule: forward packets coming from the best next hop only */
 330         if (neigh_node != router)
 331                 goto out;
 332
 333         /* don't forward the same seqno twice on one interface */
 334         if (orig_ifinfo->last_seqno_forwarded == ntohl(ogm_received->seqno))
 335                 goto out;
 336
 337         orig_ifinfo->last_seqno_forwarded = ntohl(ogm_received->seqno);
 338
 339         if (ogm_received->ttl <= 1) {
 340                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
 341                 goto out;
 342         }
 343
 344         neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 345         if (!neigh_ifinfo)
 346                 goto out;
 347
 348         tvlv_len = ntohs(ogm_received->tvlv_len);
 349
 350         packet_len = BATADV_OGM2_HLEN + tvlv_len;
 351         skb = netdev_alloc_skb_ip_align(if_outgoing->net_dev,
 352                                         ETH_HLEN + packet_len);
 353         if (!skb)
 354                 goto out;
 355
 356         skb_reserve(skb, ETH_HLEN);
 357         skb_buff = skb_put(skb, packet_len);
 358         memcpy(skb_buff, ogm_received, packet_len);
 359
 360         /* apply forward penalty */
 361         ogm_forward = (struct batadv_ogm2_packet *)skb_buff;
 362         ogm_forward->throughput = htonl(neigh_ifinfo->bat_v.throughput);
 363         ogm_forward->ttl--;
 364
 365         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 366                    "Forwarding OGM2 packet on %s: throughput %u, ttl %u, received via %s\n",
 367                    if_outgoing->net_dev->name, ntohl(ogm_forward->throughput),
 368                    ogm_forward->ttl, if_incoming->net_dev->name);
 369
 370         batadv_v_ogm_send_to_if(skb, if_outgoing);
 371
 372 out:
 373         if (orig_ifinfo)
 374                 batadv_orig_ifinfo_put(orig_ifinfo);
 375         if (router)
 376                 batadv_neigh_node_put(router);
 377         if (neigh_ifinfo)
 378                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 379 }
 380
 381 /**
 382  * batadv_v_ogm_metric_update - update route metric based on OGM
 383  * @bat_priv: the bat priv with all the soft interface information
 384  * @ogm2: OGM2 structure
 385  * @orig_node: Originator structure for which the OGM has been received
 386  * @neigh_node: the neigh_node through with the OGM has been received
 387  * @if_incoming: the interface where this packet was received
 388  * @if_outgoing: the interface for which the packet should be considered
 389  *
 390  * Return:
 391  *  1  if the OGM is new,
 392  *  0  if it is not new but valid,
 393  *  <0 on error (e.g. old OGM)
 394  */
 395 static int batadv_v_ogm_metric_update(struct batadv_priv *bat_priv,
 396                                       const struct batadv_ogm2_packet *ogm2,
 397                                       struct batadv_orig_node *orig_node,
 398                                       struct batadv_neigh_node *neigh_node,
 399                                       struct batadv_hard_iface *if_incoming,
 400                                       struct batadv_hard_iface *if_outgoing)
 401 {
 402         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 403         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 404         bool protection_started = false;
 405         int ret = -EINVAL;
 406         u32 path_throughput;
 407         s32 seq_diff;
 408
 409         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 410         if (!orig_ifinfo)
 411                 goto out;
 412
 413         seq_diff = ntohl(ogm2->seqno) - orig_ifinfo->last_real_seqno;
 414
 415         if (!hlist_empty(&orig_node->neigh_list) &&
 416             batadv_window_protected(bat_priv, seq_diff,
 417                                     BATADV_OGM_MAX_AGE,
 418                                     &orig_ifinfo->batman_seqno_reset,
 419                                     &protection_started)) {
 420                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 421                            "Drop packet: packet within window protection time from %pM\n",
 422                            ogm2->orig);
 423                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 424                            "Last reset: %ld, %ld\n",
 425                            orig_ifinfo->batman_seqno_reset, jiffies);
 426                 goto out;
 427         }
 428
 429         /* drop packets with old seqnos, however accept the first packet after
 430          * a host has been rebooted.
 431          */
 432         if ((seq_diff < 0) && !protection_started)
 433                 goto out;
 434
 435         neigh_node->last_seen = jiffies;
 436
 437         orig_node->last_seen = jiffies;
 438
 439         orig_ifinfo->last_real_seqno = ntohl(ogm2->seqno);
 440         orig_ifinfo->last_ttl = ogm2->ttl;
 441
 442         neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
 443         if (!neigh_ifinfo)
 444                 goto out;
 445
 446         path_throughput = batadv_v_forward_penalty(bat_priv, if_incoming,
 447                                                    if_outgoing,
 448                                                    ntohl(ogm2->throughput));
 449         neigh_ifinfo->bat_v.throughput = path_throughput;
 450         neigh_ifinfo->bat_v.last_seqno = ntohl(ogm2->seqno);
 451         neigh_ifinfo->last_ttl = ogm2->ttl;
 452
 453         if (seq_diff > 0 || protection_started)
 454                 ret = 1;
 455         else
 456                 ret = 0;
 457 out:
 458         if (orig_ifinfo)
 459                 batadv_orig_ifinfo_put(orig_ifinfo);
 460         if (neigh_ifinfo)
 461                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 462
 463         return ret;
 464 }
 465
 466 /**
 467  * batadv_v_ogm_route_update - update routes based on OGM
 468  * @bat_priv: the bat priv with all the soft interface information
 469  * @ethhdr: the Ethernet header of the OGM2
 470  * @ogm2: OGM2 structure
 471  * @orig_node: Originator structure for which the OGM has been received
 472  * @neigh_node: the neigh_node through with the OGM has been received
 473  * @if_incoming: the interface where this packet was received
 474  * @if_outgoing: the interface for which the packet should be considered
 475  *
 476  * Return: true if the packet should be forwarded, false otherwise
 477  */
 478 static bool batadv_v_ogm_route_update(struct batadv_priv *bat_priv,
 479                                       const struct ethhdr *ethhdr,
 480                                       const struct batadv_ogm2_packet *ogm2,
 481                                       struct batadv_orig_node *orig_node,
 482                                       struct batadv_neigh_node *neigh_node,
 483                                       struct batadv_hard_iface *if_incoming,
 484                                       struct batadv_hard_iface *if_outgoing)
 485 {
 486         struct batadv_neigh_node *router = NULL;
 487         struct batadv_orig_node *orig_neigh_node = NULL;
 488         struct batadv_neigh_node *orig_neigh_router = NULL;
 489         struct batadv_neigh_ifinfo *router_ifinfo = NULL, *neigh_ifinfo = NULL;
 490         u32 router_throughput, neigh_throughput;
 491         u32 router_last_seqno;
 492         u32 neigh_last_seqno;
 493         s32 neigh_seq_diff;
 494         bool forward = false;
 495
 496         orig_neigh_node = batadv_v_ogm_orig_get(bat_priv, ethhdr->h_source);
 497         if (!orig_neigh_node)
 498                 goto out;
 499
 500         orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
 501                                                    if_outgoing);
 502
 503         /* drop packet if sender is not a direct neighbor and if we
 504          * don't route towards it
 505          */
 506         router = batadv_orig_router_get(orig_node, if_outgoing);
 507         if (router && router->orig_node != orig_node && !orig_neigh_router) {
 508                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 509                            "Drop packet: OGM via unknown neighbor!\n");
 510                 goto out;
 511         }
 512
 513         /* Mark the OGM to be considered for forwarding, and update routes
 514          * if needed.
 515          */
 516         forward = true;
 517
 518         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 519                    "Searching and updating originator entry of received packet\n");
 520
 521         /* if this neighbor already is our next hop there is nothing
 522          * to change
 523          */
 524         if (router == neigh_node)
 525                 goto out;
 526
 527         /* don't consider neighbours with worse throughput.
 528          * also switch route if this seqno is BATADV_V_MAX_ORIGDIFF newer than
 529          * the last received seqno from our best next hop.
 530          */
 531         if (router) {
 532                 router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
 533                 neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 534
 535                 /* if these are not allocated, something is wrong. */
 536                 if (!router_ifinfo || !neigh_ifinfo)
 537                         goto out;
 538
 539                 neigh_last_seqno = neigh_ifinfo->bat_v.last_seqno;
 540                 router_last_seqno = router_ifinfo->bat_v.last_seqno;
 541                 neigh_seq_diff = neigh_last_seqno - router_last_seqno;
 542                 router_throughput = router_ifinfo->bat_v.throughput;
 543                 neigh_throughput = neigh_ifinfo->bat_v.throughput;
 544
 545                 if ((neigh_seq_diff < BATADV_OGM_MAX_ORIGDIFF) &&
 546                     (router_throughput >= neigh_throughput))
 547                         goto out;
 548         }
 549
 550         batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
 551 out:
 552         if (router)
 553                 batadv_neigh_node_put(router);
 554         if (orig_neigh_router)
 555                 batadv_neigh_node_put(orig_neigh_router);
 556         if (orig_neigh_node)
 557                 batadv_orig_node_put(orig_neigh_node);
 558         if (router_ifinfo)
 559                 batadv_neigh_ifinfo_put(router_ifinfo);
 560         if (neigh_ifinfo)
 561                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 562
 563         return forward;
 564 }
 565
 566 /**
 567  * batadv_v_ogm_process_per_outif - process a batman v OGM for an outgoing if
 568  * @bat_priv: the bat priv with all the soft interface information
 569  * @ethhdr: the Ethernet header of the OGM2
 570  * @ogm2: OGM2 structure
 571  * @orig_node: Originator structure for which the OGM has been received
 572  * @neigh_node: the neigh_node through with the OGM has been received
 573  * @if_incoming: the interface where this packet was received
 574  * @if_outgoing: the interface for which the packet should be considered
 575  */
 576 static void
 577 batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
 578                                const struct ethhdr *ethhdr,
 579                                const struct batadv_ogm2_packet *ogm2,
 580                                struct batadv_orig_node *orig_node,
 581                                struct batadv_neigh_node *neigh_node,
 582                                struct batadv_hard_iface *if_incoming,
 583                                struct batadv_hard_iface *if_outgoing)
 584 {
 585         int seqno_age;
 586         bool forward;
 587
 588         /* first, update the metric with according sanity checks */
 589         seqno_age = batadv_v_ogm_metric_update(bat_priv, ogm2, orig_node,
 590                                                neigh_node, if_incoming,
 591                                                if_outgoing);
 592
 593         /* outdated sequence numbers are to be discarded */
 594         if (seqno_age < 0)
 595                 return;
 596
 597         /* only unknown & newer OGMs contain TVLVs we are interested in */
 598         if ((seqno_age > 0) && (if_outgoing == BATADV_IF_DEFAULT))
 599                 batadv_tvlv_containers_process(bat_priv, true, orig_node,
 600                                                NULL, NULL,
 601                                                (unsigned char *)(ogm2 + 1),
 602                                                ntohs(ogm2->tvlv_len));
 603
 604         /* if the metric update went through, update routes if needed */
 605         forward = batadv_v_ogm_route_update(bat_priv, ethhdr, ogm2, orig_node,
 606                                             neigh_node, if_incoming,
 607                                             if_outgoing);
 608
 609         /* if the routes have been processed correctly, check and forward */
 610         if (forward)
 611                 batadv_v_ogm_forward(bat_priv, ogm2, orig_node, neigh_node,
 612                                      if_incoming, if_outgoing);
 613 }
 614
 615 /**
 616  * batadv_v_ogm_aggr_packet - checks if there is another OGM aggregated
 617  * @buff_pos: current position in the skb
 618  * @packet_len: total length of the skb
 619  * @tvlv_len: tvlv length of the previously considered OGM
 620  *
 621  * Return: true if there is enough space for another OGM, false otherwise.
 622  */
 623 static bool batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
 624                                      __be16 tvlv_len)
 625 {
 626         int next_buff_pos = 0;
 627
 628         next_buff_pos += buff_pos + BATADV_OGM2_HLEN;
 629         next_buff_pos += ntohs(tvlv_len);
 630
 631         return (next_buff_pos <= packet_len) &&
 632                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
 633 }
 634
 635 /**
 636  * batadv_v_ogm_process - process an incoming batman v OGM
 637  * @skb: the skb containing the OGM
 638  * @ogm_offset: offset to the OGM which should be processed (for aggregates)
 639  * @if_incoming: the interface where this packet was receved
 640  */
 641 static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
 642                                  struct batadv_hard_iface *if_incoming)
 643 {
 644         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 645         struct ethhdr *ethhdr;
 646         struct batadv_orig_node *orig_node = NULL;
 647         struct batadv_hardif_neigh_node *hardif_neigh = NULL;
 648         struct batadv_neigh_node *neigh_node = NULL;
 649         struct batadv_hard_iface *hard_iface;
 650         struct batadv_ogm2_packet *ogm_packet;
 651         u32 ogm_throughput, link_throughput, path_throughput;
 652
 653         ethhdr = eth_hdr(skb);
 654         ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
 655
 656         ogm_throughput = ntohl(ogm_packet->throughput);
 657
 658         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 659                    "Received OGM2 packet via NB: %pM, IF: %s [%pM] (from OG: %pM, seqno %u, troughput %u, TTL %u, V %u, tvlv_len %u)\n",
 660                    ethhdr->h_source, if_incoming->net_dev->name,
 661                    if_incoming->net_dev->dev_addr, ogm_packet->orig,
 662                    ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
 663                    ogm_packet->version, ntohs(ogm_packet->tvlv_len));
 664
 665         /* If the troughput metric is 0, immediately drop the packet. No need to
 666          * create orig_node / neigh_node for an unusable route.
 667          */
 668         if (ogm_throughput == 0) {
 669                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 670                            "Drop packet: originator packet with troughput metric of 0\n");
 671                 return;
 672         }
 673
 674         /* require ELP packets be to received from this neighbor first */
 675         hardif_neigh = batadv_hardif_neigh_get(if_incoming, ethhdr->h_source);
 676         if (!hardif_neigh) {
 677                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 678                            "Drop packet: OGM via unknown neighbor!\n");
 679                 goto out;
 680         }
 681
 682         orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
 683         if (!orig_node)
 684                 return;
 685
 686         neigh_node = batadv_neigh_node_new(orig_node, if_incoming,
 687                                            ethhdr->h_source);
 688         if (!neigh_node)
 689                 goto out;
 690
 691         /* Update the received throughput metric to match the link
 692          * characteristic:
 693          *  - If this OGM traveled one hop so far (emitted by single hop
 694          *    neighbor) the path throughput metric equals the link throughput.
 695          *  - For OGMs traversing more than hop the path throughput metric is
 696          *    the smaller of the path throughput and the link throughput.
 697          */
 698         link_throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
 699         path_throughput = min_t(u32, link_throughput, ogm_throughput);
 700         ogm_packet->throughput = htonl(path_throughput);
 701
 702         batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet, orig_node,
 703                                        neigh_node, if_incoming,
 704                                        BATADV_IF_DEFAULT);
 705
 706         rcu_read_lock();
 707         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 708                 if (hard_iface->if_status != BATADV_IF_ACTIVE)
 709                         continue;
 710
 711                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 712                         continue;
 713
 714                 if (!kref_get_unless_zero(&hard_iface->refcount))
 715                         continue;
 716
 717                 batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,
 718                                                orig_node, neigh_node,
 719                                                if_incoming, hard_iface);
 720
 721                 batadv_hardif_put(hard_iface);
 722         }
 723         rcu_read_unlock();
 724 out:
 725         if (orig_node)
 726                 batadv_orig_node_put(orig_node);
 727         if (neigh_node)
 728                 batadv_neigh_node_put(neigh_node);
 729         if (hardif_neigh)
 730                 batadv_hardif_neigh_put(hardif_neigh);
 731 }
 732
 733 /**
 734  * batadv_v_ogm_packet_recv - OGM2 receiving handler
 735  * @skb: the received OGM
 736  * @if_incoming: the interface where this OGM has been received
 737  *
 738  * Return: NET_RX_SUCCESS and consume the skb on success or returns NET_RX_DROP
 739  * (without freeing the skb) on failure
 740  */
 741 int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 742                              struct batadv_hard_iface *if_incoming)
 743 {
 744         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 745         struct batadv_ogm2_packet *ogm_packet;
 746         struct ethhdr *ethhdr = eth_hdr(skb);
 747         int ogm_offset;
 748         u8 *packet_pos;
 749         int ret = NET_RX_DROP;
 750
 751         /* did we receive a OGM2 packet on an interface that does not have
 752          * B.A.T.M.A.N. V enabled ?
 753          */
 754         if (strcmp(bat_priv->bat_algo_ops->name, "BATMAN_V") != 0)
 755                 return NET_RX_DROP;
 756
 757         if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
 758                 return NET_RX_DROP;
 759
 760         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 761                 return NET_RX_DROP;
 762
 763         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 764
 765         if (batadv_is_my_mac(bat_priv, ogm_packet->orig))
 766                 return NET_RX_DROP;
 767
 768         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
 769         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
 770                            skb->len + ETH_HLEN);
 771
 772         ogm_offset = 0;
 773         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 774
 775         while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
 776                                         ogm_packet->tvlv_len)) {
 777                 batadv_v_ogm_process(skb, ogm_offset, if_incoming);
 778
 779                 ogm_offset += BATADV_OGM2_HLEN;
 780                 ogm_offset += ntohs(ogm_packet->tvlv_len);
 781
 782                 packet_pos = skb->data + ogm_offset;
 783                 ogm_packet = (struct batadv_ogm2_packet *)packet_pos;
 784         }
 785
 786         ret = NET_RX_SUCCESS;
 787         consume_skb(skb);
 788
 789         return ret;
 790 }
 791
 792 /**
 793  * batadv_v_ogm_init - initialise the OGM2 engine
 794  * @bat_priv: the bat priv with all the soft interface information
 795  *
 796  * Return: 0 on success or a negative error code in case of failure
 797  */
 798 int batadv_v_ogm_init(struct batadv_priv *bat_priv)
 799 {
 800         struct batadv_ogm2_packet *ogm_packet;
 801         unsigned char *ogm_buff;
 802         u32 random_seqno;
 803
 804         bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
 805         ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
 806         if (!ogm_buff)
 807                 return -ENOMEM;
 808
 809         bat_priv->bat_v.ogm_buff = ogm_buff;
 810         ogm_packet = (struct batadv_ogm2_packet *)ogm_buff;
 811         ogm_packet->packet_type = BATADV_OGM2;
 812         ogm_packet->version = BATADV_COMPAT_VERSION;
 813         ogm_packet->ttl = BATADV_TTL;
 814         ogm_packet->flags = BATADV_NO_FLAGS;
 815         ogm_packet->throughput = htonl(BATADV_THROUGHPUT_MAX_VALUE);
 816
 817         /* randomize initial seqno to avoid collision */
 818         get_random_bytes(&random_seqno, sizeof(random_seqno));
 819         atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
 820         INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
 821
 822         return 0;
 823 }
 824
 825 /**
 826  * batadv_v_ogm_free - free OGM private resources
 827  * @bat_priv: the bat priv with all the soft interface information
 828  */
 829 void batadv_v_ogm_free(struct batadv_priv *bat_priv)
 830 {
 831         cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
 832
 833         kfree(bat_priv->bat_v.ogm_buff);
 834         bat_priv->bat_v.ogm_buff = NULL;
 835         bat_priv->bat_v.ogm_buff_len = 0;
 836 }