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         kref_get(&orig_node->refcount);
  77         hash_added = batadv_hash_add(bat_priv->orig_hash, batadv_compare_orig,
  78                                      batadv_choose_orig, orig_node,
  79                                      &orig_node->hash_entry);
  80         if (hash_added != 0) {
  81                 /* remove refcnt for newly created orig_node and hash entry */
  82                 batadv_orig_node_put(orig_node);
  83                 batadv_orig_node_put(orig_node);
  84                 orig_node = NULL;
  85         }
  86
  87         return orig_node;
  88 }
  89
  90 /**
  91  * batadv_v_ogm_start_timer - restart the OGM sending timer
  92  * @bat_priv: the bat priv with all the soft interface information
  93  */
  94 static void batadv_v_ogm_start_timer(struct batadv_priv *bat_priv)
  95 {
  96         unsigned long msecs;
  97         /* this function may be invoked in different contexts (ogm rescheduling
  98          * or hard_iface activation), but the work timer should not be reset
  99          */
 100         if (delayed_work_pending(&bat_priv->bat_v.ogm_wq))
 101                 return;
 102
 103         msecs = atomic_read(&bat_priv->orig_interval) - BATADV_JITTER;
 104         msecs += prandom_u32() % (2 * BATADV_JITTER);
 105         queue_delayed_work(batadv_event_workqueue, &bat_priv->bat_v.ogm_wq,
 106                            msecs_to_jiffies(msecs));
 107 }
 108
 109 /**
 110  * batadv_v_ogm_send_to_if - send a batman ogm using a given interface
 111  * @skb: the OGM to send
 112  * @hard_iface: the interface to use to send the OGM
 113  */
 114 static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
 115                                     struct batadv_hard_iface *hard_iface)
 116 {
 117         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 118
 119         if (hard_iface->if_status != BATADV_IF_ACTIVE)
 120                 return;
 121
 122         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
 123         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
 124                            skb->len + ETH_HLEN);
 125
 126         batadv_send_broadcast_skb(skb, hard_iface);
 127 }
 128
 129 /**
 130  * batadv_v_ogm_send - periodic worker broadcasting the own OGM
 131  * @work: work queue item
 132  */
 133 static void batadv_v_ogm_send(struct work_struct *work)
 134 {
 135         struct batadv_hard_iface *hard_iface;
 136         struct batadv_priv_bat_v *bat_v;
 137         struct batadv_priv *bat_priv;
 138         struct batadv_ogm2_packet *ogm_packet;
 139         struct sk_buff *skb, *skb_tmp;
 140         unsigned char *ogm_buff, *pkt_buff;
 141         int ogm_buff_len;
 142         u16 tvlv_len = 0;
 143
 144         bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
 145         bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
 146
 147         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
 148                 goto out;
 149
 150         ogm_buff = bat_priv->bat_v.ogm_buff;
 151         ogm_buff_len = bat_priv->bat_v.ogm_buff_len;
 152         /* tt changes have to be committed before the tvlv data is
 153          * appended as it may alter the tt tvlv container
 154          */
 155         batadv_tt_local_commit_changes(bat_priv);
 156         tvlv_len = batadv_tvlv_container_ogm_append(bat_priv, &ogm_buff,
 157                                                     &ogm_buff_len,
 158                                                     BATADV_OGM2_HLEN);
 159
 160         bat_priv->bat_v.ogm_buff = ogm_buff;
 161         bat_priv->bat_v.ogm_buff_len = ogm_buff_len;
 162
 163         skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + ogm_buff_len);
 164         if (!skb)
 165                 goto reschedule;
 166
 167         skb_reserve(skb, ETH_HLEN);
 168         pkt_buff = skb_put(skb, ogm_buff_len);
 169         memcpy(pkt_buff, ogm_buff, ogm_buff_len);
 170
 171         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 172         ogm_packet->seqno = htonl(atomic_read(&bat_priv->bat_v.ogm_seqno));
 173         atomic_inc(&bat_priv->bat_v.ogm_seqno);
 174         ogm_packet->tvlv_len = htons(tvlv_len);
 175
 176         /* broadcast on every interface */
 177         rcu_read_lock();
 178         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 179                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 180                         continue;
 181
 182                 if (!kref_get_unless_zero(&hard_iface->refcount))
 183                         continue;
 184
 185                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 186                            "Sending own OGM2 packet (originator %pM, seqno %u, throughput %u, TTL %d) on interface %s [%pM]\n",
 187                            ogm_packet->orig, ntohl(ogm_packet->seqno),
 188                            ntohl(ogm_packet->throughput), ogm_packet->ttl,
 189                            hard_iface->net_dev->name,
 190                            hard_iface->net_dev->dev_addr);
 191
 192                 /* this skb gets consumed by batadv_v_ogm_send_to_if() */
 193                 skb_tmp = skb_clone(skb, GFP_ATOMIC);
 194                 if (!skb_tmp) {
 195                         batadv_hardif_put(hard_iface);
 196                         break;
 197                 }
 198
 199                 batadv_v_ogm_send_to_if(skb_tmp, hard_iface);
 200                 batadv_hardif_put(hard_iface);
 201         }
 202         rcu_read_unlock();
 203
 204         consume_skb(skb);
 205
 206 reschedule:
 207         batadv_v_ogm_start_timer(bat_priv);
 208 out:
 209         return;
 210 }
 211
 212 /**
 213  * batadv_v_ogm_iface_enable - prepare an interface for B.A.T.M.A.N. V
 214  * @hard_iface: the interface to prepare
 215  *
 216  * Takes care of scheduling own OGM sending routine for this interface.
 217  *
 218  * Return: 0 on success or a negative error code otherwise
 219  */
 220 int batadv_v_ogm_iface_enable(struct batadv_hard_iface *hard_iface)
 221 {
 222         struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 223
 224         batadv_v_ogm_start_timer(bat_priv);
 225
 226         return 0;
 227 }
 228
 229 /**
 230  * batadv_v_ogm_primary_iface_set - set a new primary interface
 231  * @primary_iface: the new primary interface
 232  */
 233 void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
 234 {
 235         struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
 236         struct batadv_ogm2_packet *ogm_packet;
 237
 238         if (!bat_priv->bat_v.ogm_buff)
 239                 return;
 240
 241         ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
 242         ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
 243 }
 244
 245 /**
 246  * batadv_v_forward_penalty - apply a penalty to the throughput metric forwarded
 247  *  with B.A.T.M.A.N. V OGMs
 248  * @bat_priv: the bat priv with all the soft interface information
 249  * @if_incoming: the interface where the OGM has been received
 250  * @if_outgoing: the interface where the OGM has to be forwarded to
 251  * @throughput: the current throughput
 252  *
 253  * Apply a penalty on the current throughput metric value based on the
 254  * characteristic of the interface where the OGM has been received. The return
 255  * value is computed as follows:
 256  * - throughput * 50%          if the incoming and outgoing interface are the
 257  *                             same WiFi interface and the throughput is above
 258  *                             1MBit/s
 259  * - throughput                if the outgoing interface is the default
 260  *                             interface (i.e. this OGM is processed for the
 261  *                             internal table and not forwarded)
 262  * - throughput * hop penalty  otherwise
 263  *
 264  * Return: the penalised throughput metric.
 265  */
 266 static u32 batadv_v_forward_penalty(struct batadv_priv *bat_priv,
 267                                     struct batadv_hard_iface *if_incoming,
 268                                     struct batadv_hard_iface *if_outgoing,
 269                                     u32 throughput)
 270 {
 271         int hop_penalty = atomic_read(&bat_priv->hop_penalty);
 272         int hop_penalty_max = BATADV_TQ_MAX_VALUE;
 273
 274         /* Don't apply hop penalty in default originator table. */
 275         if (if_outgoing == BATADV_IF_DEFAULT)
 276                 return throughput;
 277
 278         /* Forwarding on the same WiFi interface cuts the throughput in half
 279          * due to the store & forward characteristics of WIFI.
 280          * Very low throughput values are the exception.
 281          */
 282         if ((throughput > 10) &&
 283             (if_incoming == if_outgoing) &&
 284             !(if_incoming->bat_v.flags & BATADV_FULL_DUPLEX))
 285                 return throughput / 2;
 286
 287         /* hop penalty of 255 equals 100% */
 288         return throughput * (hop_penalty_max - hop_penalty) / hop_penalty_max;
 289 }
 290
 291 /**
 292  * batadv_v_ogm_forward - check conditions and forward an OGM to the given
 293  *  outgoing interface
 294  * @bat_priv: the bat priv with all the soft interface information
 295  * @ogm_received: previously received OGM to be forwarded
 296  * @orig_node: the originator which has been updated
 297  * @neigh_node: the neigh_node through with the OGM has been received
 298  * @if_incoming: the interface on which this OGM was received on
 299  * @if_outgoing: the interface to which the OGM has to be forwarded to
 300  *
 301  * Forward an OGM to an interface after having altered the throughput metric and
 302  * the TTL value contained in it. The original OGM isn't modified.
 303  */
 304 static void batadv_v_ogm_forward(struct batadv_priv *bat_priv,
 305                                  const struct batadv_ogm2_packet *ogm_received,
 306                                  struct batadv_orig_node *orig_node,
 307                                  struct batadv_neigh_node *neigh_node,
 308                                  struct batadv_hard_iface *if_incoming,
 309                                  struct batadv_hard_iface *if_outgoing)
 310 {
 311         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 312         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 313         struct batadv_neigh_node *router = NULL;
 314         struct batadv_ogm2_packet *ogm_forward;
 315         unsigned char *skb_buff;
 316         struct sk_buff *skb;
 317         size_t packet_len;
 318         u16 tvlv_len;
 319
 320         /* only forward for specific interfaces, not for the default one. */
 321         if (if_outgoing == BATADV_IF_DEFAULT)
 322                 goto out;
 323
 324         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 325         if (!orig_ifinfo)
 326                 goto out;
 327
 328         /* acquire possibly updated router */
 329         router = batadv_orig_router_get(orig_node, if_outgoing);
 330
 331         /* strict rule: forward packets coming from the best next hop only */
 332         if (neigh_node != router)
 333                 goto out;
 334
 335         /* don't forward the same seqno twice on one interface */
 336         if (orig_ifinfo->last_seqno_forwarded == ntohl(ogm_received->seqno))
 337                 goto out;
 338
 339         orig_ifinfo->last_seqno_forwarded = ntohl(ogm_received->seqno);
 340
 341         if (ogm_received->ttl <= 1) {
 342                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv, "ttl exceeded\n");
 343                 goto out;
 344         }
 345
 346         neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 347         if (!neigh_ifinfo)
 348                 goto out;
 349
 350         tvlv_len = ntohs(ogm_received->tvlv_len);
 351
 352         packet_len = BATADV_OGM2_HLEN + tvlv_len;
 353         skb = netdev_alloc_skb_ip_align(if_outgoing->net_dev,
 354                                         ETH_HLEN + packet_len);
 355         if (!skb)
 356                 goto out;
 357
 358         skb_reserve(skb, ETH_HLEN);
 359         skb_buff = skb_put(skb, packet_len);
 360         memcpy(skb_buff, ogm_received, packet_len);
 361
 362         /* apply forward penalty */
 363         ogm_forward = (struct batadv_ogm2_packet *)skb_buff;
 364         ogm_forward->throughput = htonl(neigh_ifinfo->bat_v.throughput);
 365         ogm_forward->ttl--;
 366
 367         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 368                    "Forwarding OGM2 packet on %s: throughput %u, ttl %u, received via %s\n",
 369                    if_outgoing->net_dev->name, ntohl(ogm_forward->throughput),
 370                    ogm_forward->ttl, if_incoming->net_dev->name);
 371
 372         batadv_v_ogm_send_to_if(skb, if_outgoing);
 373
 374 out:
 375         if (orig_ifinfo)
 376                 batadv_orig_ifinfo_put(orig_ifinfo);
 377         if (router)
 378                 batadv_neigh_node_put(router);
 379         if (neigh_ifinfo)
 380                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 381 }
 382
 383 /**
 384  * batadv_v_ogm_metric_update - update route metric based on OGM
 385  * @bat_priv: the bat priv with all the soft interface information
 386  * @ogm2: OGM2 structure
 387  * @orig_node: Originator structure for which the OGM has been received
 388  * @neigh_node: the neigh_node through with the OGM has been received
 389  * @if_incoming: the interface where this packet was received
 390  * @if_outgoing: the interface for which the packet should be considered
 391  *
 392  * Return:
 393  *  1  if the OGM is new,
 394  *  0  if it is not new but valid,
 395  *  <0 on error (e.g. old OGM)
 396  */
 397 static int batadv_v_ogm_metric_update(struct batadv_priv *bat_priv,
 398                                       const struct batadv_ogm2_packet *ogm2,
 399                                       struct batadv_orig_node *orig_node,
 400                                       struct batadv_neigh_node *neigh_node,
 401                                       struct batadv_hard_iface *if_incoming,
 402                                       struct batadv_hard_iface *if_outgoing)
 403 {
 404         struct batadv_orig_ifinfo *orig_ifinfo = NULL;
 405         struct batadv_neigh_ifinfo *neigh_ifinfo = NULL;
 406         bool protection_started = false;
 407         int ret = -EINVAL;
 408         u32 path_throughput;
 409         s32 seq_diff;
 410
 411         orig_ifinfo = batadv_orig_ifinfo_new(orig_node, if_outgoing);
 412         if (!orig_ifinfo)
 413                 goto out;
 414
 415         seq_diff = ntohl(ogm2->seqno) - orig_ifinfo->last_real_seqno;
 416
 417         if (!hlist_empty(&orig_node->neigh_list) &&
 418             batadv_window_protected(bat_priv, seq_diff,
 419                                     BATADV_OGM_MAX_AGE,
 420                                     &orig_ifinfo->batman_seqno_reset,
 421                                     &protection_started)) {
 422                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 423                            "Drop packet: packet within window protection time from %pM\n",
 424                            ogm2->orig);
 425                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 426                            "Last reset: %ld, %ld\n",
 427                            orig_ifinfo->batman_seqno_reset, jiffies);
 428                 goto out;
 429         }
 430
 431         /* drop packets with old seqnos, however accept the first packet after
 432          * a host has been rebooted.
 433          */
 434         if ((seq_diff < 0) && !protection_started)
 435                 goto out;
 436
 437         neigh_node->last_seen = jiffies;
 438
 439         orig_node->last_seen = jiffies;
 440
 441         orig_ifinfo->last_real_seqno = ntohl(ogm2->seqno);
 442         orig_ifinfo->last_ttl = ogm2->ttl;
 443
 444         neigh_ifinfo = batadv_neigh_ifinfo_new(neigh_node, if_outgoing);
 445         if (!neigh_ifinfo)
 446                 goto out;
 447
 448         path_throughput = batadv_v_forward_penalty(bat_priv, if_incoming,
 449                                                    if_outgoing,
 450                                                    ntohl(ogm2->throughput));
 451         neigh_ifinfo->bat_v.throughput = path_throughput;
 452         neigh_ifinfo->bat_v.last_seqno = ntohl(ogm2->seqno);
 453         neigh_ifinfo->last_ttl = ogm2->ttl;
 454
 455         if (seq_diff > 0 || protection_started)
 456                 ret = 1;
 457         else
 458                 ret = 0;
 459 out:
 460         if (orig_ifinfo)
 461                 batadv_orig_ifinfo_put(orig_ifinfo);
 462         if (neigh_ifinfo)
 463                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 464
 465         return ret;
 466 }
 467
 468 /**
 469  * batadv_v_ogm_route_update - update routes based on OGM
 470  * @bat_priv: the bat priv with all the soft interface information
 471  * @ethhdr: the Ethernet header of the OGM2
 472  * @ogm2: OGM2 structure
 473  * @orig_node: Originator structure for which the OGM has been received
 474  * @neigh_node: the neigh_node through with the OGM has been received
 475  * @if_incoming: the interface where this packet was received
 476  * @if_outgoing: the interface for which the packet should be considered
 477  *
 478  * Return: true if the packet should be forwarded, false otherwise
 479  */
 480 static bool batadv_v_ogm_route_update(struct batadv_priv *bat_priv,
 481                                       const struct ethhdr *ethhdr,
 482                                       const struct batadv_ogm2_packet *ogm2,
 483                                       struct batadv_orig_node *orig_node,
 484                                       struct batadv_neigh_node *neigh_node,
 485                                       struct batadv_hard_iface *if_incoming,
 486                                       struct batadv_hard_iface *if_outgoing)
 487 {
 488         struct batadv_neigh_node *router = NULL;
 489         struct batadv_orig_node *orig_neigh_node = NULL;
 490         struct batadv_neigh_node *orig_neigh_router = NULL;
 491         struct batadv_neigh_ifinfo *router_ifinfo = NULL, *neigh_ifinfo = NULL;
 492         u32 router_throughput, neigh_throughput;
 493         u32 router_last_seqno;
 494         u32 neigh_last_seqno;
 495         s32 neigh_seq_diff;
 496         bool forward = false;
 497
 498         orig_neigh_node = batadv_v_ogm_orig_get(bat_priv, ethhdr->h_source);
 499         if (!orig_neigh_node)
 500                 goto out;
 501
 502         orig_neigh_router = batadv_orig_router_get(orig_neigh_node,
 503                                                    if_outgoing);
 504
 505         /* drop packet if sender is not a direct neighbor and if we
 506          * don't route towards it
 507          */
 508         router = batadv_orig_router_get(orig_node, if_outgoing);
 509         if (router && router->orig_node != orig_node && !orig_neigh_router) {
 510                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 511                            "Drop packet: OGM via unknown neighbor!\n");
 512                 goto out;
 513         }
 514
 515         /* Mark the OGM to be considered for forwarding, and update routes
 516          * if needed.
 517          */
 518         forward = true;
 519
 520         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 521                    "Searching and updating originator entry of received packet\n");
 522
 523         /* if this neighbor already is our next hop there is nothing
 524          * to change
 525          */
 526         if (router == neigh_node)
 527                 goto out;
 528
 529         /* don't consider neighbours with worse throughput.
 530          * also switch route if this seqno is BATADV_V_MAX_ORIGDIFF newer than
 531          * the last received seqno from our best next hop.
 532          */
 533         if (router) {
 534                 router_ifinfo = batadv_neigh_ifinfo_get(router, if_outgoing);
 535                 neigh_ifinfo = batadv_neigh_ifinfo_get(neigh_node, if_outgoing);
 536
 537                 /* if these are not allocated, something is wrong. */
 538                 if (!router_ifinfo || !neigh_ifinfo)
 539                         goto out;
 540
 541                 neigh_last_seqno = neigh_ifinfo->bat_v.last_seqno;
 542                 router_last_seqno = router_ifinfo->bat_v.last_seqno;
 543                 neigh_seq_diff = neigh_last_seqno - router_last_seqno;
 544                 router_throughput = router_ifinfo->bat_v.throughput;
 545                 neigh_throughput = neigh_ifinfo->bat_v.throughput;
 546
 547                 if ((neigh_seq_diff < BATADV_OGM_MAX_ORIGDIFF) &&
 548                     (router_throughput >= neigh_throughput))
 549                         goto out;
 550         }
 551
 552         batadv_update_route(bat_priv, orig_node, if_outgoing, neigh_node);
 553 out:
 554         if (router)
 555                 batadv_neigh_node_put(router);
 556         if (orig_neigh_router)
 557                 batadv_neigh_node_put(orig_neigh_router);
 558         if (orig_neigh_node)
 559                 batadv_orig_node_put(orig_neigh_node);
 560         if (router_ifinfo)
 561                 batadv_neigh_ifinfo_put(router_ifinfo);
 562         if (neigh_ifinfo)
 563                 batadv_neigh_ifinfo_put(neigh_ifinfo);
 564
 565         return forward;
 566 }
 567
 568 /**
 569  * batadv_v_ogm_process_per_outif - process a batman v OGM for an outgoing if
 570  * @bat_priv: the bat priv with all the soft interface information
 571  * @ethhdr: the Ethernet header of the OGM2
 572  * @ogm2: OGM2 structure
 573  * @orig_node: Originator structure for which the OGM has been received
 574  * @neigh_node: the neigh_node through with the OGM has been received
 575  * @if_incoming: the interface where this packet was received
 576  * @if_outgoing: the interface for which the packet should be considered
 577  */
 578 static void
 579 batadv_v_ogm_process_per_outif(struct batadv_priv *bat_priv,
 580                                const struct ethhdr *ethhdr,
 581                                const struct batadv_ogm2_packet *ogm2,
 582                                struct batadv_orig_node *orig_node,
 583                                struct batadv_neigh_node *neigh_node,
 584                                struct batadv_hard_iface *if_incoming,
 585                                struct batadv_hard_iface *if_outgoing)
 586 {
 587         int seqno_age;
 588         bool forward;
 589
 590         /* first, update the metric with according sanity checks */
 591         seqno_age = batadv_v_ogm_metric_update(bat_priv, ogm2, orig_node,
 592                                                neigh_node, if_incoming,
 593                                                if_outgoing);
 594
 595         /* outdated sequence numbers are to be discarded */
 596         if (seqno_age < 0)
 597                 return;
 598
 599         /* only unknown & newer OGMs contain TVLVs we are interested in */
 600         if ((seqno_age > 0) && (if_outgoing == BATADV_IF_DEFAULT))
 601                 batadv_tvlv_containers_process(bat_priv, true, orig_node,
 602                                                NULL, NULL,
 603                                                (unsigned char *)(ogm2 + 1),
 604                                                ntohs(ogm2->tvlv_len));
 605
 606         /* if the metric update went through, update routes if needed */
 607         forward = batadv_v_ogm_route_update(bat_priv, ethhdr, ogm2, orig_node,
 608                                             neigh_node, if_incoming,
 609                                             if_outgoing);
 610
 611         /* if the routes have been processed correctly, check and forward */
 612         if (forward)
 613                 batadv_v_ogm_forward(bat_priv, ogm2, orig_node, neigh_node,
 614                                      if_incoming, if_outgoing);
 615 }
 616
 617 /**
 618  * batadv_v_ogm_aggr_packet - checks if there is another OGM aggregated
 619  * @buff_pos: current position in the skb
 620  * @packet_len: total length of the skb
 621  * @tvlv_len: tvlv length of the previously considered OGM
 622  *
 623  * Return: true if there is enough space for another OGM, false otherwise.
 624  */
 625 static bool batadv_v_ogm_aggr_packet(int buff_pos, int packet_len,
 626                                      __be16 tvlv_len)
 627 {
 628         int next_buff_pos = 0;
 629
 630         next_buff_pos += buff_pos + BATADV_OGM2_HLEN;
 631         next_buff_pos += ntohs(tvlv_len);
 632
 633         return (next_buff_pos <= packet_len) &&
 634                (next_buff_pos <= BATADV_MAX_AGGREGATION_BYTES);
 635 }
 636
 637 /**
 638  * batadv_v_ogm_process - process an incoming batman v OGM
 639  * @skb: the skb containing the OGM
 640  * @ogm_offset: offset to the OGM which should be processed (for aggregates)
 641  * @if_incoming: the interface where this packet was receved
 642  */
 643 static void batadv_v_ogm_process(const struct sk_buff *skb, int ogm_offset,
 644                                  struct batadv_hard_iface *if_incoming)
 645 {
 646         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 647         struct ethhdr *ethhdr;
 648         struct batadv_orig_node *orig_node = NULL;
 649         struct batadv_hardif_neigh_node *hardif_neigh = NULL;
 650         struct batadv_neigh_node *neigh_node = NULL;
 651         struct batadv_hard_iface *hard_iface;
 652         struct batadv_ogm2_packet *ogm_packet;
 653         u32 ogm_throughput, link_throughput, path_throughput;
 654
 655         ethhdr = eth_hdr(skb);
 656         ogm_packet = (struct batadv_ogm2_packet *)(skb->data + ogm_offset);
 657
 658         ogm_throughput = ntohl(ogm_packet->throughput);
 659
 660         batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 661                    "Received OGM2 packet via NB: %pM, IF: %s [%pM] (from OG: %pM, seqno %u, troughput %u, TTL %u, V %u, tvlv_len %u)\n",
 662                    ethhdr->h_source, if_incoming->net_dev->name,
 663                    if_incoming->net_dev->dev_addr, ogm_packet->orig,
 664                    ntohl(ogm_packet->seqno), ogm_throughput, ogm_packet->ttl,
 665                    ogm_packet->version, ntohs(ogm_packet->tvlv_len));
 666
 667         /* If the troughput metric is 0, immediately drop the packet. No need to
 668          * create orig_node / neigh_node for an unusable route.
 669          */
 670         if (ogm_throughput == 0) {
 671                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 672                            "Drop packet: originator packet with troughput metric of 0\n");
 673                 return;
 674         }
 675
 676         /* require ELP packets be to received from this neighbor first */
 677         hardif_neigh = batadv_hardif_neigh_get(if_incoming, ethhdr->h_source);
 678         if (!hardif_neigh) {
 679                 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 680                            "Drop packet: OGM via unknown neighbor!\n");
 681                 goto out;
 682         }
 683
 684         orig_node = batadv_v_ogm_orig_get(bat_priv, ogm_packet->orig);
 685         if (!orig_node)
 686                 return;
 687
 688         neigh_node = batadv_neigh_node_get_or_create(orig_node, if_incoming,
 689                                                      ethhdr->h_source);
 690         if (!neigh_node)
 691                 goto out;
 692
 693         /* Update the received throughput metric to match the link
 694          * characteristic:
 695          *  - If this OGM traveled one hop so far (emitted by single hop
 696          *    neighbor) the path throughput metric equals the link throughput.
 697          *  - For OGMs traversing more than hop the path throughput metric is
 698          *    the smaller of the path throughput and the link throughput.
 699          */
 700         link_throughput = ewma_throughput_read(&hardif_neigh->bat_v.throughput);
 701         path_throughput = min_t(u32, link_throughput, ogm_throughput);
 702         ogm_packet->throughput = htonl(path_throughput);
 703
 704         batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet, orig_node,
 705                                        neigh_node, if_incoming,
 706                                        BATADV_IF_DEFAULT);
 707
 708         rcu_read_lock();
 709         list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
 710                 if (hard_iface->if_status != BATADV_IF_ACTIVE)
 711                         continue;
 712
 713                 if (hard_iface->soft_iface != bat_priv->soft_iface)
 714                         continue;
 715
 716                 if (!kref_get_unless_zero(&hard_iface->refcount))
 717                         continue;
 718
 719                 batadv_v_ogm_process_per_outif(bat_priv, ethhdr, ogm_packet,
 720                                                orig_node, neigh_node,
 721                                                if_incoming, hard_iface);
 722
 723                 batadv_hardif_put(hard_iface);
 724         }
 725         rcu_read_unlock();
 726 out:
 727         if (orig_node)
 728                 batadv_orig_node_put(orig_node);
 729         if (neigh_node)
 730                 batadv_neigh_node_put(neigh_node);
 731         if (hardif_neigh)
 732                 batadv_hardif_neigh_put(hardif_neigh);
 733 }
 734
 735 /**
 736  * batadv_v_ogm_packet_recv - OGM2 receiving handler
 737  * @skb: the received OGM
 738  * @if_incoming: the interface where this OGM has been received
 739  *
 740  * Return: NET_RX_SUCCESS and consume the skb on success or returns NET_RX_DROP
 741  * (without freeing the skb) on failure
 742  */
 743 int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 744                              struct batadv_hard_iface *if_incoming)
 745 {
 746         struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 747         struct batadv_ogm2_packet *ogm_packet;
 748         struct ethhdr *ethhdr = eth_hdr(skb);
 749         int ogm_offset;
 750         u8 *packet_pos;
 751         int ret = NET_RX_DROP;
 752
 753         /* did we receive a OGM2 packet on an interface that does not have
 754          * B.A.T.M.A.N. V enabled ?
 755          */
 756         if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
 757                 return NET_RX_DROP;
 758
 759         if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
 760                 return NET_RX_DROP;
 761
 762         if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 763                 return NET_RX_DROP;
 764
 765         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 766
 767         if (batadv_is_my_mac(bat_priv, ogm_packet->orig))
 768                 return NET_RX_DROP;
 769
 770         batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_RX);
 771         batadv_add_counter(bat_priv, BATADV_CNT_MGMT_RX_BYTES,
 772                            skb->len + ETH_HLEN);
 773
 774         ogm_offset = 0;
 775         ogm_packet = (struct batadv_ogm2_packet *)skb->data;
 776
 777         while (batadv_v_ogm_aggr_packet(ogm_offset, skb_headlen(skb),
 778                                         ogm_packet->tvlv_len)) {
 779                 batadv_v_ogm_process(skb, ogm_offset, if_incoming);
 780
 781                 ogm_offset += BATADV_OGM2_HLEN;
 782                 ogm_offset += ntohs(ogm_packet->tvlv_len);
 783
 784                 packet_pos = skb->data + ogm_offset;
 785                 ogm_packet = (struct batadv_ogm2_packet *)packet_pos;
 786         }
 787
 788         ret = NET_RX_SUCCESS;
 789         consume_skb(skb);
 790
 791         return ret;
 792 }
 793
 794 /**
 795  * batadv_v_ogm_init - initialise the OGM2 engine
 796  * @bat_priv: the bat priv with all the soft interface information
 797  *
 798  * Return: 0 on success or a negative error code in case of failure
 799  */
 800 int batadv_v_ogm_init(struct batadv_priv *bat_priv)
 801 {
 802         struct batadv_ogm2_packet *ogm_packet;
 803         unsigned char *ogm_buff;
 804         u32 random_seqno;
 805
 806         bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
 807         ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
 808         if (!ogm_buff)
 809                 return -ENOMEM;
 810
 811         bat_priv->bat_v.ogm_buff = ogm_buff;
 812         ogm_packet = (struct batadv_ogm2_packet *)ogm_buff;
 813         ogm_packet->packet_type = BATADV_OGM2;
 814         ogm_packet->version = BATADV_COMPAT_VERSION;
 815         ogm_packet->ttl = BATADV_TTL;
 816         ogm_packet->flags = BATADV_NO_FLAGS;
 817         ogm_packet->throughput = htonl(BATADV_THROUGHPUT_MAX_VALUE);
 818
 819         /* randomize initial seqno to avoid collision */
 820         get_random_bytes(&random_seqno, sizeof(random_seqno));
 821         atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
 822         INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
 823
 824         return 0;
 825 }
 826
 827 /**
 828  * batadv_v_ogm_free - free OGM private resources
 829  * @bat_priv: the bat priv with all the soft interface information
 830  */
 831 void batadv_v_ogm_free(struct batadv_priv *bat_priv)
 832 {
 833         cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
 834
 835         kfree(bat_priv->bat_v.ogm_buff);
 836         bat_priv->bat_v.ogm_buff = NULL;
 837         bat_priv->bat_v.ogm_buff_len = 0;
 838 }