net/batman-adv/network-coding.c

   1 /* Copyright (C) 2012-2015 B.A.T.M.A.N. contributors:
   2  *
   3  * Martin Hundebøll, Jeppe Ledet-Pedersen
   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 "network-coding.h"
  19 #include "main.h"
  20
  21 #include <linux/atomic.h>
  22 #include <linux/bitops.h>
  23 #include <linux/byteorder/generic.h>
  24 #include <linux/compiler.h>
  25 #include <linux/debugfs.h>
  26 #include <linux/errno.h>
  27 #include <linux/etherdevice.h>
  28 #include <linux/fs.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/if_packet.h>
  31 #include <linux/init.h>
  32 #include <linux/jhash.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/kernel.h>
  35 #include <linux/list.h>
  36 #include <linux/lockdep.h>
  37 #include <linux/netdevice.h>
  38 #include <linux/printk.h>
  39 #include <linux/random.h>
  40 #include <linux/rculist.h>
  41 #include <linux/rcupdate.h>
  42 #include <linux/seq_file.h>
  43 #include <linux/skbuff.h>
  44 #include <linux/slab.h>
  45 #include <linux/spinlock.h>
  46 #include <linux/stat.h>
  47 #include <linux/stddef.h>
  48 #include <linux/string.h>
  49 #include <linux/workqueue.h>
  50
  51 #include "hard-interface.h"
  52 #include "hash.h"
  53 #include "originator.h"
  54 #include "packet.h"
  55 #include "routing.h"
  56 #include "send.h"
  57
  58 static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
  59 static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
  60
  61 static void batadv_nc_worker(struct work_struct *work);
  62 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
  63                                        struct batadv_hard_iface *recv_if);
  64
  65 /**
  66  * batadv_nc_init - one-time initialization for network coding
  67  */
  68 int __init batadv_nc_init(void)
  69 {
  70         int ret;
  71
  72         /* Register our packet type */
  73         ret = batadv_recv_handler_register(BATADV_CODED,
  74                                            batadv_nc_recv_coded_packet);
  75
  76         return ret;
  77 }
  78
  79 /**
  80  * batadv_nc_start_timer - initialise the nc periodic worker
  81  * @bat_priv: the bat priv with all the soft interface information
  82  */
  83 static void batadv_nc_start_timer(struct batadv_priv *bat_priv)
  84 {
  85         queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work,
  86                            msecs_to_jiffies(10));
  87 }
  88
  89 /**
  90  * batadv_nc_tvlv_container_update - update the network coding tvlv container
  91  *  after network coding setting change
  92  * @bat_priv: the bat priv with all the soft interface information
  93  */
  94 static void batadv_nc_tvlv_container_update(struct batadv_priv *bat_priv)
  95 {
  96         char nc_mode;
  97
  98         nc_mode = atomic_read(&bat_priv->network_coding);
  99
 100         switch (nc_mode) {
 101         case 0:
 102                 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
 103                 break;
 104         case 1:
 105                 batadv_tvlv_container_register(bat_priv, BATADV_TVLV_NC, 1,
 106                                                NULL, 0);
 107                 break;
 108         }
 109 }
 110
 111 /**
 112  * batadv_nc_status_update - update the network coding tvlv container after
 113  *  network coding setting change
 114  * @net_dev: the soft interface net device
 115  */
 116 void batadv_nc_status_update(struct net_device *net_dev)
 117 {
 118         struct batadv_priv *bat_priv = netdev_priv(net_dev);
 119
 120         batadv_nc_tvlv_container_update(bat_priv);
 121 }
 122
 123 /**
 124  * batadv_nc_tvlv_ogm_handler_v1 - process incoming nc tvlv container
 125  * @bat_priv: the bat priv with all the soft interface information
 126  * @orig: the orig_node of the ogm
 127  * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
 128  * @tvlv_value: tvlv buffer containing the gateway data
 129  * @tvlv_value_len: tvlv buffer length
 130  */
 131 static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
 132                                           struct batadv_orig_node *orig,
 133                                           u8 flags,
 134                                           void *tvlv_value, u16 tvlv_value_len)
 135 {
 136         if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
 137                 clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
 138         else
 139                 set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
 140 }
 141
 142 /**
 143  * batadv_nc_mesh_init - initialise coding hash table and start house keeping
 144  * @bat_priv: the bat priv with all the soft interface information
 145  */
 146 int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
 147 {
 148         bat_priv->nc.timestamp_fwd_flush = jiffies;
 149         bat_priv->nc.timestamp_sniffed_purge = jiffies;
 150
 151         if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
 152                 return 0;
 153
 154         bat_priv->nc.coding_hash = batadv_hash_new(128);
 155         if (!bat_priv->nc.coding_hash)
 156                 goto err;
 157
 158         batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
 159                                    &batadv_nc_coding_hash_lock_class_key);
 160
 161         bat_priv->nc.decoding_hash = batadv_hash_new(128);
 162         if (!bat_priv->nc.decoding_hash)
 163                 goto err;
 164
 165         batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
 166                                    &batadv_nc_decoding_hash_lock_class_key);
 167
 168         INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
 169         batadv_nc_start_timer(bat_priv);
 170
 171         batadv_tvlv_handler_register(bat_priv, batadv_nc_tvlv_ogm_handler_v1,
 172                                      NULL, BATADV_TVLV_NC, 1,
 173                                      BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
 174         batadv_nc_tvlv_container_update(bat_priv);
 175         return 0;
 176
 177 err:
 178         return -ENOMEM;
 179 }
 180
 181 /**
 182  * batadv_nc_init_bat_priv - initialise the nc specific bat_priv variables
 183  * @bat_priv: the bat priv with all the soft interface information
 184  */
 185 void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
 186 {
 187         atomic_set(&bat_priv->network_coding, 0);
 188         bat_priv->nc.min_tq = 200;
 189         bat_priv->nc.max_fwd_delay = 10;
 190         bat_priv->nc.max_buffer_time = 200;
 191 }
 192
 193 /**
 194  * batadv_nc_init_orig - initialise the nc fields of an orig_node
 195  * @orig_node: the orig_node which is going to be initialised
 196  */
 197 void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
 198 {
 199         INIT_LIST_HEAD(&orig_node->in_coding_list);
 200         INIT_LIST_HEAD(&orig_node->out_coding_list);
 201         spin_lock_init(&orig_node->in_coding_list_lock);
 202         spin_lock_init(&orig_node->out_coding_list_lock);
 203 }
 204
 205 /**
 206  * batadv_nc_node_release - release nc_node from lists and queue for free after
 207  *  rcu grace period
 208  * @nc_node: the nc node to free
 209  */
 210 static void batadv_nc_node_release(struct batadv_nc_node *nc_node)
 211 {
 212         batadv_orig_node_free_ref(nc_node->orig_node);
 213         kfree_rcu(nc_node, rcu);
 214 }
 215
 216 /**
 217  * batadv_nc_node_free_ref - decrement the nc node refcounter and possibly
 218  *  release it
 219  * @nc_node: the nc node to free
 220  */
 221 static void batadv_nc_node_free_ref(struct batadv_nc_node *nc_node)
 222 {
 223         if (atomic_dec_and_test(&nc_node->refcount))
 224                 batadv_nc_node_release(nc_node);
 225 }
 226
 227 /**
 228  * batadv_nc_path_free_ref - decrements the nc path refcounter and possibly
 229  * frees it
 230  * @nc_path: the nc node to free
 231  */
 232 static void batadv_nc_path_free_ref(struct batadv_nc_path *nc_path)
 233 {
 234         if (atomic_dec_and_test(&nc_path->refcount))
 235                 kfree_rcu(nc_path, rcu);
 236 }
 237
 238 /**
 239  * batadv_nc_packet_free - frees nc packet
 240  * @nc_packet: the nc packet to free
 241  */
 242 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet)
 243 {
 244         if (nc_packet->skb)
 245                 kfree_skb(nc_packet->skb);
 246
 247         batadv_nc_path_free_ref(nc_packet->nc_path);
 248         kfree(nc_packet);
 249 }
 250
 251 /**
 252  * batadv_nc_to_purge_nc_node - checks whether an nc node has to be purged
 253  * @bat_priv: the bat priv with all the soft interface information
 254  * @nc_node: the nc node to check
 255  *
 256  * Returns true if the entry has to be purged now, false otherwise
 257  */
 258 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
 259                                        struct batadv_nc_node *nc_node)
 260 {
 261         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 262                 return true;
 263
 264         return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
 265 }
 266
 267 /**
 268  * batadv_nc_to_purge_nc_path_coding - checks whether an nc path has timed out
 269  * @bat_priv: the bat priv with all the soft interface information
 270  * @nc_path: the nc path to check
 271  *
 272  * Returns true if the entry has to be purged now, false otherwise
 273  */
 274 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
 275                                               struct batadv_nc_path *nc_path)
 276 {
 277         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 278                 return true;
 279
 280         /* purge the path when no packets has been added for 10 times the
 281          * max_fwd_delay time
 282          */
 283         return batadv_has_timed_out(nc_path->last_valid,
 284                                     bat_priv->nc.max_fwd_delay * 10);
 285 }
 286
 287 /**
 288  * batadv_nc_to_purge_nc_path_decoding - checks whether an nc path has timed out
 289  * @bat_priv: the bat priv with all the soft interface information
 290  * @nc_path: the nc path to check
 291  *
 292  * Returns true if the entry has to be purged now, false otherwise
 293  */
 294 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
 295                                                 struct batadv_nc_path *nc_path)
 296 {
 297         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 298                 return true;
 299
 300         /* purge the path when no packets has been added for 10 times the
 301          * max_buffer time
 302          */
 303         return batadv_has_timed_out(nc_path->last_valid,
 304                                     bat_priv->nc.max_buffer_time * 10);
 305 }
 306
 307 /**
 308  * batadv_nc_purge_orig_nc_nodes - go through list of nc nodes and purge stale
 309  *  entries
 310  * @bat_priv: the bat priv with all the soft interface information
 311  * @list: list of nc nodes
 312  * @lock: nc node list lock
 313  * @to_purge: function in charge to decide whether an entry has to be purged or
 314  *            not. This function takes the nc node as argument and has to return
 315  *            a boolean value: true if the entry has to be deleted, false
 316  *            otherwise
 317  */
 318 static void
 319 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
 320                               struct list_head *list,
 321                               spinlock_t *lock,
 322                               bool (*to_purge)(struct batadv_priv *,
 323                                                struct batadv_nc_node *))
 324 {
 325         struct batadv_nc_node *nc_node, *nc_node_tmp;
 326
 327         /* For each nc_node in list */
 328         spin_lock_bh(lock);
 329         list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
 330                 /* if an helper function has been passed as parameter,
 331                  * ask it if the entry has to be purged or not
 332                  */
 333                 if (to_purge && !to_purge(bat_priv, nc_node))
 334                         continue;
 335
 336                 batadv_dbg(BATADV_DBG_NC, bat_priv,
 337                            "Removing nc_node %pM -> %pM\n",
 338                            nc_node->addr, nc_node->orig_node->orig);
 339                 list_del_rcu(&nc_node->list);
 340                 batadv_nc_node_free_ref(nc_node);
 341         }
 342         spin_unlock_bh(lock);
 343 }
 344
 345 /**
 346  * batadv_nc_purge_orig - purges all nc node data attached of the given
 347  *  originator
 348  * @bat_priv: the bat priv with all the soft interface information
 349  * @orig_node: orig_node with the nc node entries to be purged
 350  * @to_purge: function in charge to decide whether an entry has to be purged or
 351  *            not. This function takes the nc node as argument and has to return
 352  *            a boolean value: true is the entry has to be deleted, false
 353  *            otherwise
 354  */
 355 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
 356                           struct batadv_orig_node *orig_node,
 357                           bool (*to_purge)(struct batadv_priv *,
 358                                            struct batadv_nc_node *))
 359 {
 360         /* Check ingoing nc_node's of this orig_node */
 361         batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
 362                                       &orig_node->in_coding_list_lock,
 363                                       to_purge);
 364
 365         /* Check outgoing nc_node's of this orig_node */
 366         batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
 367                                       &orig_node->out_coding_list_lock,
 368                                       to_purge);
 369 }
 370
 371 /**
 372  * batadv_nc_purge_orig_hash - traverse entire originator hash to check if they
 373  *  have timed out nc nodes
 374  * @bat_priv: the bat priv with all the soft interface information
 375  */
 376 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
 377 {
 378         struct batadv_hashtable *hash = bat_priv->orig_hash;
 379         struct hlist_head *head;
 380         struct batadv_orig_node *orig_node;
 381         u32 i;
 382
 383         if (!hash)
 384                 return;
 385
 386         /* For each orig_node */
 387         for (i = 0; i < hash->size; i++) {
 388                 head = &hash->table[i];
 389
 390                 rcu_read_lock();
 391                 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
 392                         batadv_nc_purge_orig(bat_priv, orig_node,
 393                                              batadv_nc_to_purge_nc_node);
 394                 rcu_read_unlock();
 395         }
 396 }
 397
 398 /**
 399  * batadv_nc_purge_paths - traverse all nc paths part of the hash and remove
 400  *  unused ones
 401  * @bat_priv: the bat priv with all the soft interface information
 402  * @hash: hash table containing the nc paths to check
 403  * @to_purge: function in charge to decide whether an entry has to be purged or
 404  *            not. This function takes the nc node as argument and has to return
 405  *            a boolean value: true is the entry has to be deleted, false
 406  *            otherwise
 407  */
 408 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
 409                                   struct batadv_hashtable *hash,
 410                                   bool (*to_purge)(struct batadv_priv *,
 411                                                    struct batadv_nc_path *))
 412 {
 413         struct hlist_head *head;
 414         struct hlist_node *node_tmp;
 415         struct batadv_nc_path *nc_path;
 416         spinlock_t *lock; /* Protects lists in hash */
 417         u32 i;
 418
 419         for (i = 0; i < hash->size; i++) {
 420                 head = &hash->table[i];
 421                 lock = &hash->list_locks[i];
 422
 423                 /* For each nc_path in this bin */
 424                 spin_lock_bh(lock);
 425                 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
 426                         /* if an helper function has been passed as parameter,
 427                          * ask it if the entry has to be purged or not
 428                          */
 429                         if (to_purge && !to_purge(bat_priv, nc_path))
 430                                 continue;
 431
 432                         /* purging an non-empty nc_path should never happen, but
 433                          * is observed under high CPU load. Delay the purging
 434                          * until next iteration to allow the packet_list to be
 435                          * emptied first.
 436                          */
 437                         if (!unlikely(list_empty(&nc_path->packet_list))) {
 438                                 net_ratelimited_function(printk,
 439                                                          KERN_WARNING
 440                                                          "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
 441                                                          nc_path->prev_hop,
 442                                                          nc_path->next_hop);
 443                                 continue;
 444                         }
 445
 446                         /* nc_path is unused, so remove it */
 447                         batadv_dbg(BATADV_DBG_NC, bat_priv,
 448                                    "Remove nc_path %pM -> %pM\n",
 449                                    nc_path->prev_hop, nc_path->next_hop);
 450                         hlist_del_rcu(&nc_path->hash_entry);
 451                         batadv_nc_path_free_ref(nc_path);
 452                 }
 453                 spin_unlock_bh(lock);
 454         }
 455 }
 456
 457 /**
 458  * batadv_nc_hash_key_gen - computes the nc_path hash key
 459  * @key: buffer to hold the final hash key
 460  * @src: source ethernet mac address going into the hash key
 461  * @dst: destination ethernet mac address going into the hash key
 462  */
 463 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
 464                                    const char *dst)
 465 {
 466         memcpy(key->prev_hop, src, sizeof(key->prev_hop));
 467         memcpy(key->next_hop, dst, sizeof(key->next_hop));
 468 }
 469
 470 /**
 471  * batadv_nc_hash_choose - compute the hash value for an nc path
 472  * @data: data to hash
 473  * @size: size of the hash table
 474  *
 475  * Returns the selected index in the hash table for the given data.
 476  */
 477 static u32 batadv_nc_hash_choose(const void *data, u32 size)
 478 {
 479         const struct batadv_nc_path *nc_path = data;
 480         u32 hash = 0;
 481
 482         hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
 483         hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
 484
 485         return hash % size;
 486 }
 487
 488 /**
 489  * batadv_nc_hash_compare - comparing function used in the network coding hash
 490  *  tables
 491  * @node: node in the local table
 492  * @data2: second object to compare the node to
 493  *
 494  * Returns 1 if the two entry are the same, 0 otherwise
 495  */
 496 static int batadv_nc_hash_compare(const struct hlist_node *node,
 497                                   const void *data2)
 498 {
 499         const struct batadv_nc_path *nc_path1, *nc_path2;
 500
 501         nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
 502         nc_path2 = data2;
 503
 504         /* Return 1 if the two keys are identical */
 505         if (memcmp(nc_path1->prev_hop, nc_path2->prev_hop,
 506                    sizeof(nc_path1->prev_hop)) != 0)
 507                 return 0;
 508
 509         if (memcmp(nc_path1->next_hop, nc_path2->next_hop,
 510                    sizeof(nc_path1->next_hop)) != 0)
 511                 return 0;
 512
 513         return 1;
 514 }
 515
 516 /**
 517  * batadv_nc_hash_find - search for an existing nc path and return it
 518  * @hash: hash table containing the nc path
 519  * @data: search key
 520  *
 521  * Returns the nc_path if found, NULL otherwise.
 522  */
 523 static struct batadv_nc_path *
 524 batadv_nc_hash_find(struct batadv_hashtable *hash,
 525                     void *data)
 526 {
 527         struct hlist_head *head;
 528         struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
 529         int index;
 530
 531         if (!hash)
 532                 return NULL;
 533
 534         index = batadv_nc_hash_choose(data, hash->size);
 535         head = &hash->table[index];
 536
 537         rcu_read_lock();
 538         hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
 539                 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
 540                         continue;
 541
 542                 if (!atomic_inc_not_zero(&nc_path->refcount))
 543                         continue;
 544
 545                 nc_path_tmp = nc_path;
 546                 break;
 547         }
 548         rcu_read_unlock();
 549
 550         return nc_path_tmp;
 551 }
 552
 553 /**
 554  * batadv_nc_send_packet - send non-coded packet and free nc_packet struct
 555  * @nc_packet: the nc packet to send
 556  */
 557 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
 558 {
 559         batadv_send_skb_packet(nc_packet->skb,
 560                                nc_packet->neigh_node->if_incoming,
 561                                nc_packet->nc_path->next_hop);
 562         nc_packet->skb = NULL;
 563         batadv_nc_packet_free(nc_packet);
 564 }
 565
 566 /**
 567  * batadv_nc_sniffed_purge - Checks timestamp of given sniffed nc_packet.
 568  * @bat_priv: the bat priv with all the soft interface information
 569  * @nc_path: the nc path the packet belongs to
 570  * @nc_packet: the nc packet to be checked
 571  *
 572  * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
 573  * timeout. If so, the packet is no longer kept and the entry deleted from the
 574  * queue. Has to be called with the appropriate locks.
 575  *
 576  * Returns false as soon as the entry in the fifo queue has not been timed out
 577  * yet and true otherwise.
 578  */
 579 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
 580                                     struct batadv_nc_path *nc_path,
 581                                     struct batadv_nc_packet *nc_packet)
 582 {
 583         unsigned long timeout = bat_priv->nc.max_buffer_time;
 584         bool res = false;
 585
 586         lockdep_assert_held(&nc_path->packet_list_lock);
 587
 588         /* Packets are added to tail, so the remaining packets did not time
 589          * out and we can stop processing the current queue
 590          */
 591         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
 592             !batadv_has_timed_out(nc_packet->timestamp, timeout))
 593                 goto out;
 594
 595         /* purge nc packet */
 596         list_del(&nc_packet->list);
 597         batadv_nc_packet_free(nc_packet);
 598
 599         res = true;
 600
 601 out:
 602         return res;
 603 }
 604
 605 /**
 606  * batadv_nc_fwd_flush - Checks the timestamp of the given nc packet.
 607  * @bat_priv: the bat priv with all the soft interface information
 608  * @nc_path: the nc path the packet belongs to
 609  * @nc_packet: the nc packet to be checked
 610  *
 611  * Checks whether the given nc packet has hit its forward timeout. If so, the
 612  * packet is no longer delayed, immediately sent and the entry deleted from the
 613  * queue. Has to be called with the appropriate locks.
 614  *
 615  * Returns false as soon as the entry in the fifo queue has not been timed out
 616  * yet and true otherwise.
 617  */
 618 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
 619                                 struct batadv_nc_path *nc_path,
 620                                 struct batadv_nc_packet *nc_packet)
 621 {
 622         unsigned long timeout = bat_priv->nc.max_fwd_delay;
 623
 624         lockdep_assert_held(&nc_path->packet_list_lock);
 625
 626         /* Packets are added to tail, so the remaining packets did not time
 627          * out and we can stop processing the current queue
 628          */
 629         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
 630             !batadv_has_timed_out(nc_packet->timestamp, timeout))
 631                 return false;
 632
 633         /* Send packet */
 634         batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 635         batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 636                            nc_packet->skb->len + ETH_HLEN);
 637         list_del(&nc_packet->list);
 638         batadv_nc_send_packet(nc_packet);
 639
 640         return true;
 641 }
 642
 643 /**
 644  * batadv_nc_process_nc_paths - traverse given nc packet pool and free timed out
 645  *  nc packets
 646  * @bat_priv: the bat priv with all the soft interface information
 647  * @hash: to be processed hash table
 648  * @process_fn: Function called to process given nc packet. Should return true
 649  *              to encourage this function to proceed with the next packet.
 650  *              Otherwise the rest of the current queue is skipped.
 651  */
 652 static void
 653 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
 654                            struct batadv_hashtable *hash,
 655                            bool (*process_fn)(struct batadv_priv *,
 656                                               struct batadv_nc_path *,
 657                                               struct batadv_nc_packet *))
 658 {
 659         struct hlist_head *head;
 660         struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
 661         struct batadv_nc_path *nc_path;
 662         bool ret;
 663         int i;
 664
 665         if (!hash)
 666                 return;
 667
 668         /* Loop hash table bins */
 669         for (i = 0; i < hash->size; i++) {
 670                 head = &hash->table[i];
 671
 672                 /* Loop coding paths */
 673                 rcu_read_lock();
 674                 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
 675                         /* Loop packets */
 676                         spin_lock_bh(&nc_path->packet_list_lock);
 677                         list_for_each_entry_safe(nc_packet, nc_packet_tmp,
 678                                                  &nc_path->packet_list, list) {
 679                                 ret = process_fn(bat_priv, nc_path, nc_packet);
 680                                 if (!ret)
 681                                         break;
 682                         }
 683                         spin_unlock_bh(&nc_path->packet_list_lock);
 684                 }
 685                 rcu_read_unlock();
 686         }
 687 }
 688
 689 /**
 690  * batadv_nc_worker - periodic task for house keeping related to network coding
 691  * @work: kernel work struct
 692  */
 693 static void batadv_nc_worker(struct work_struct *work)
 694 {
 695         struct delayed_work *delayed_work;
 696         struct batadv_priv_nc *priv_nc;
 697         struct batadv_priv *bat_priv;
 698         unsigned long timeout;
 699
 700         delayed_work = container_of(work, struct delayed_work, work);
 701         priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
 702         bat_priv = container_of(priv_nc, struct batadv_priv, nc);
 703
 704         batadv_nc_purge_orig_hash(bat_priv);
 705         batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
 706                               batadv_nc_to_purge_nc_path_coding);
 707         batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
 708                               batadv_nc_to_purge_nc_path_decoding);
 709
 710         timeout = bat_priv->nc.max_fwd_delay;
 711
 712         if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
 713                 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
 714                                            batadv_nc_fwd_flush);
 715                 bat_priv->nc.timestamp_fwd_flush = jiffies;
 716         }
 717
 718         if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
 719                                  bat_priv->nc.max_buffer_time)) {
 720                 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
 721                                            batadv_nc_sniffed_purge);
 722                 bat_priv->nc.timestamp_sniffed_purge = jiffies;
 723         }
 724
 725         /* Schedule a new check */
 726         batadv_nc_start_timer(bat_priv);
 727 }
 728
 729 /**
 730  * batadv_can_nc_with_orig - checks whether the given orig node is suitable for
 731  *  coding or not
 732  * @bat_priv: the bat priv with all the soft interface information
 733  * @orig_node: neighboring orig node which may be used as nc candidate
 734  * @ogm_packet: incoming ogm packet also used for the checks
 735  *
 736  * Returns true if:
 737  *  1) The OGM must have the most recent sequence number.
 738  *  2) The TTL must be decremented by one and only one.
 739  *  3) The OGM must be received from the first hop from orig_node.
 740  *  4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
 741  */
 742 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
 743                                     struct batadv_orig_node *orig_node,
 744                                     struct batadv_ogm_packet *ogm_packet)
 745 {
 746         struct batadv_orig_ifinfo *orig_ifinfo;
 747         u32 last_real_seqno;
 748         u8 last_ttl;
 749
 750         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
 751         if (!orig_ifinfo)
 752                 return false;
 753
 754         last_ttl = orig_ifinfo->last_ttl;
 755         last_real_seqno = orig_ifinfo->last_real_seqno;
 756         batadv_orig_ifinfo_free_ref(orig_ifinfo);
 757
 758         if (last_real_seqno != ntohl(ogm_packet->seqno))
 759                 return false;
 760         if (last_ttl != ogm_packet->ttl + 1)
 761                 return false;
 762         if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
 763                 return false;
 764         if (ogm_packet->tq < bat_priv->nc.min_tq)
 765                 return false;
 766
 767         return true;
 768 }
 769
 770 /**
 771  * batadv_nc_find_nc_node - search for an existing nc node and return it
 772  * @orig_node: orig node originating the ogm packet
 773  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
 774  *  (can be equal to orig_node)
 775  * @in_coding: traverse incoming or outgoing network coding list
 776  *
 777  * Returns the nc_node if found, NULL otherwise.
 778  */
 779 static struct batadv_nc_node
 780 *batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
 781                         struct batadv_orig_node *orig_neigh_node,
 782                         bool in_coding)
 783 {
 784         struct batadv_nc_node *nc_node, *nc_node_out = NULL;
 785         struct list_head *list;
 786
 787         if (in_coding)
 788                 list = &orig_neigh_node->in_coding_list;
 789         else
 790                 list = &orig_neigh_node->out_coding_list;
 791
 792         /* Traverse list of nc_nodes to orig_node */
 793         rcu_read_lock();
 794         list_for_each_entry_rcu(nc_node, list, list) {
 795                 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
 796                         continue;
 797
 798                 if (!atomic_inc_not_zero(&nc_node->refcount))
 799                         continue;
 800
 801                 /* Found a match */
 802                 nc_node_out = nc_node;
 803                 break;
 804         }
 805         rcu_read_unlock();
 806
 807         return nc_node_out;
 808 }
 809
 810 /**
 811  * batadv_nc_get_nc_node - retrieves an nc node or creates the entry if it was
 812  *  not found
 813  * @bat_priv: the bat priv with all the soft interface information
 814  * @orig_node: orig node originating the ogm packet
 815  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
 816  *  (can be equal to orig_node)
 817  * @in_coding: traverse incoming or outgoing network coding list
 818  *
 819  * Returns the nc_node if found or created, NULL in case of an error.
 820  */
 821 static struct batadv_nc_node
 822 *batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
 823                        struct batadv_orig_node *orig_node,
 824                        struct batadv_orig_node *orig_neigh_node,
 825                        bool in_coding)
 826 {
 827         struct batadv_nc_node *nc_node;
 828         spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
 829         struct list_head *list;
 830
 831         /* Select ingoing or outgoing coding node */
 832         if (in_coding) {
 833                 lock = &orig_neigh_node->in_coding_list_lock;
 834                 list = &orig_neigh_node->in_coding_list;
 835         } else {
 836                 lock = &orig_neigh_node->out_coding_list_lock;
 837                 list = &orig_neigh_node->out_coding_list;
 838         }
 839
 840         spin_lock_bh(lock);
 841
 842         /* Check if nc_node is already added */
 843         nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
 844
 845         /* Node found */
 846         if (nc_node)
 847                 goto unlock;
 848
 849         nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
 850         if (!nc_node)
 851                 goto unlock;
 852
 853         atomic_inc(&orig_neigh_node->refcount);
 854
 855         /* Initialize nc_node */
 856         INIT_LIST_HEAD(&nc_node->list);
 857         ether_addr_copy(nc_node->addr, orig_node->orig);
 858         nc_node->orig_node = orig_neigh_node;
 859         atomic_set(&nc_node->refcount, 2);
 860
 861         batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
 862                    nc_node->addr, nc_node->orig_node->orig);
 863
 864         /* Add nc_node to orig_node */
 865         list_add_tail_rcu(&nc_node->list, list);
 866 unlock:
 867         spin_unlock_bh(lock);
 868
 869         return nc_node;
 870 }
 871
 872 /**
 873  * batadv_nc_update_nc_node - updates stored incoming and outgoing nc node
 874  *  structs (best called on incoming OGMs)
 875  * @bat_priv: the bat priv with all the soft interface information
 876  * @orig_node: orig node originating the ogm packet
 877  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
 878  *  (can be equal to orig_node)
 879  * @ogm_packet: incoming ogm packet
 880  * @is_single_hop_neigh: orig_node is a single hop neighbor
 881  */
 882 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
 883                               struct batadv_orig_node *orig_node,
 884                               struct batadv_orig_node *orig_neigh_node,
 885                               struct batadv_ogm_packet *ogm_packet,
 886                               int is_single_hop_neigh)
 887 {
 888         struct batadv_nc_node *in_nc_node = NULL;
 889         struct batadv_nc_node *out_nc_node = NULL;
 890
 891         /* Check if network coding is enabled */
 892         if (!atomic_read(&bat_priv->network_coding))
 893                 goto out;
 894
 895         /* check if orig node is network coding enabled */
 896         if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
 897                 goto out;
 898
 899         /* accept ogms from 'good' neighbors and single hop neighbors */
 900         if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
 901             !is_single_hop_neigh)
 902                 goto out;
 903
 904         /* Add orig_node as in_nc_node on hop */
 905         in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
 906                                            orig_neigh_node, true);
 907         if (!in_nc_node)
 908                 goto out;
 909
 910         in_nc_node->last_seen = jiffies;
 911
 912         /* Add hop as out_nc_node on orig_node */
 913         out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
 914                                             orig_node, false);
 915         if (!out_nc_node)
 916                 goto out;
 917
 918         out_nc_node->last_seen = jiffies;
 919
 920 out:
 921         if (in_nc_node)
 922                 batadv_nc_node_free_ref(in_nc_node);
 923         if (out_nc_node)
 924                 batadv_nc_node_free_ref(out_nc_node);
 925 }
 926
 927 /**
 928  * batadv_nc_get_path - get existing nc_path or allocate a new one
 929  * @bat_priv: the bat priv with all the soft interface information
 930  * @hash: hash table containing the nc path
 931  * @src: ethernet source address - first half of the nc path search key
 932  * @dst: ethernet destination address - second half of the nc path search key
 933  *
 934  * Returns pointer to nc_path if the path was found or created, returns NULL
 935  * on error.
 936  */
 937 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
 938                                                  struct batadv_hashtable *hash,
 939                                                  u8 *src,
 940                                                  u8 *dst)
 941 {
 942         int hash_added;
 943         struct batadv_nc_path *nc_path, nc_path_key;
 944
 945         batadv_nc_hash_key_gen(&nc_path_key, src, dst);
 946
 947         /* Search for existing nc_path */
 948         nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
 949
 950         if (nc_path) {
 951                 /* Set timestamp to delay removal of nc_path */
 952                 nc_path->last_valid = jiffies;
 953                 return nc_path;
 954         }
 955
 956         /* No existing nc_path was found; create a new */
 957         nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
 958
 959         if (!nc_path)
 960                 return NULL;
 961
 962         /* Initialize nc_path */
 963         INIT_LIST_HEAD(&nc_path->packet_list);
 964         spin_lock_init(&nc_path->packet_list_lock);
 965         atomic_set(&nc_path->refcount, 2);
 966         nc_path->last_valid = jiffies;
 967         ether_addr_copy(nc_path->next_hop, dst);
 968         ether_addr_copy(nc_path->prev_hop, src);
 969
 970         batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
 971                    nc_path->prev_hop,
 972                    nc_path->next_hop);
 973
 974         /* Add nc_path to hash table */
 975         hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
 976                                      batadv_nc_hash_choose, &nc_path_key,
 977                                      &nc_path->hash_entry);
 978
 979         if (hash_added < 0) {
 980                 kfree(nc_path);
 981                 return NULL;
 982         }
 983
 984         return nc_path;
 985 }
 986
 987 /**
 988  * batadv_nc_random_weight_tq - scale the receivers TQ-value to avoid unfair
 989  *  selection of a receiver with slightly lower TQ than the other
 990  * @tq: to be weighted tq value
 991  */
 992 static u8 batadv_nc_random_weight_tq(u8 tq)
 993 {
 994         /* randomize the estimated packet loss (max TQ - estimated TQ) */
 995         u8 rand_tq = prandom_u32_max(BATADV_TQ_MAX_VALUE + 1 - tq);
 996
 997         /* convert to (randomized) estimated tq again */
 998         return BATADV_TQ_MAX_VALUE - rand_tq;
 999 }
1000
1001 /**
1002  * batadv_nc_memxor - XOR destination with source
1003  * @dst: byte array to XOR into
1004  * @src: byte array to XOR from
1005  * @len: length of destination array
1006  */
1007 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
1008 {
1009         unsigned int i;
1010
1011         for (i = 0; i < len; ++i)
1012                 dst[i] ^= src[i];
1013 }
1014
1015 /**
1016  * batadv_nc_code_packets - code a received unicast_packet with an nc packet
1017  *  into a coded_packet and send it
1018  * @bat_priv: the bat priv with all the soft interface information
1019  * @skb: data skb to forward
1020  * @ethhdr: pointer to the ethernet header inside the skb
1021  * @nc_packet: structure containing the packet to the skb can be coded with
1022  * @neigh_node: next hop to forward packet to
1023  *
1024  * Returns true if both packets are consumed, false otherwise.
1025  */
1026 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1027                                    struct sk_buff *skb,
1028                                    struct ethhdr *ethhdr,
1029                                    struct batadv_nc_packet *nc_packet,
1030                                    struct batadv_neigh_node *neigh_node)
1031 {
1032         u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1033         struct sk_buff *skb_dest, *skb_src;
1034         struct batadv_unicast_packet *packet1;
1035         struct batadv_unicast_packet *packet2;
1036         struct batadv_coded_packet *coded_packet;
1037         struct batadv_neigh_node *neigh_tmp, *router_neigh;
1038         struct batadv_neigh_node *router_coding = NULL;
1039         struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1040         struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1041         u8 *first_source, *first_dest, *second_source, *second_dest;
1042         __be32 packet_id1, packet_id2;
1043         size_t count;
1044         bool res = false;
1045         int coding_len;
1046         int unicast_size = sizeof(*packet1);
1047         int coded_size = sizeof(*coded_packet);
1048         int header_add = coded_size - unicast_size;
1049
1050         /* TODO: do we need to consider the outgoing interface for
1051          * coded packets?
1052          */
1053         router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1054                                               BATADV_IF_DEFAULT);
1055         if (!router_neigh)
1056                 goto out;
1057
1058         router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1059                                                       BATADV_IF_DEFAULT);
1060         if (!router_neigh_ifinfo)
1061                 goto out;
1062
1063         neigh_tmp = nc_packet->neigh_node;
1064         router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1065                                                BATADV_IF_DEFAULT);
1066         if (!router_coding)
1067                 goto out;
1068
1069         router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1070                                                        BATADV_IF_DEFAULT);
1071         if (!router_coding_ifinfo)
1072                 goto out;
1073
1074         tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1075         tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1076         tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1077         tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1078
1079         /* Select one destination for the MAC-header dst-field based on
1080          * weighted TQ-values.
1081          */
1082         if (tq_weighted_neigh >= tq_weighted_coding) {
1083                 /* Destination from nc_packet is selected for MAC-header */
1084                 first_dest = nc_packet->nc_path->next_hop;
1085                 first_source = nc_packet->nc_path->prev_hop;
1086                 second_dest = neigh_node->addr;
1087                 second_source = ethhdr->h_source;
1088                 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1089                 packet2 = (struct batadv_unicast_packet *)skb->data;
1090                 packet_id1 = nc_packet->packet_id;
1091                 packet_id2 = batadv_skb_crc32(skb,
1092                                               skb->data + sizeof(*packet2));
1093         } else {
1094                 /* Destination for skb is selected for MAC-header */
1095                 first_dest = neigh_node->addr;
1096                 first_source = ethhdr->h_source;
1097                 second_dest = nc_packet->nc_path->next_hop;
1098                 second_source = nc_packet->nc_path->prev_hop;
1099                 packet1 = (struct batadv_unicast_packet *)skb->data;
1100                 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1101                 packet_id1 = batadv_skb_crc32(skb,
1102                                               skb->data + sizeof(*packet1));
1103                 packet_id2 = nc_packet->packet_id;
1104         }
1105
1106         /* Instead of zero padding the smallest data buffer, we
1107          * code into the largest.
1108          */
1109         if (skb->len <= nc_packet->skb->len) {
1110                 skb_dest = nc_packet->skb;
1111                 skb_src = skb;
1112         } else {
1113                 skb_dest = skb;
1114                 skb_src = nc_packet->skb;
1115         }
1116
1117         /* coding_len is used when decoding the packet shorter packet */
1118         coding_len = skb_src->len - unicast_size;
1119
1120         if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1121                 goto out;
1122
1123         skb_push(skb_dest, header_add);
1124
1125         coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1126         skb_reset_mac_header(skb_dest);
1127
1128         coded_packet->packet_type = BATADV_CODED;
1129         coded_packet->version = BATADV_COMPAT_VERSION;
1130         coded_packet->ttl = packet1->ttl;
1131
1132         /* Info about first unicast packet */
1133         ether_addr_copy(coded_packet->first_source, first_source);
1134         ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1135         coded_packet->first_crc = packet_id1;
1136         coded_packet->first_ttvn = packet1->ttvn;
1137
1138         /* Info about second unicast packet */
1139         ether_addr_copy(coded_packet->second_dest, second_dest);
1140         ether_addr_copy(coded_packet->second_source, second_source);
1141         ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1142         coded_packet->second_crc = packet_id2;
1143         coded_packet->second_ttl = packet2->ttl;
1144         coded_packet->second_ttvn = packet2->ttvn;
1145         coded_packet->coded_len = htons(coding_len);
1146
1147         /* This is where the magic happens: Code skb_src into skb_dest */
1148         batadv_nc_memxor(skb_dest->data + coded_size,
1149                          skb_src->data + unicast_size, coding_len);
1150
1151         /* Update counters accordingly */
1152         if (BATADV_SKB_CB(skb_src)->decoded &&
1153             BATADV_SKB_CB(skb_dest)->decoded) {
1154                 /* Both packets are recoded */
1155                 count = skb_src->len + ETH_HLEN;
1156                 count += skb_dest->len + ETH_HLEN;
1157                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1158                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1159         } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1160                    !BATADV_SKB_CB(skb_dest)->decoded) {
1161                 /* Both packets are newly coded */
1162                 count = skb_src->len + ETH_HLEN;
1163                 count += skb_dest->len + ETH_HLEN;
1164                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1165                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1166         } else if (BATADV_SKB_CB(skb_src)->decoded &&
1167                    !BATADV_SKB_CB(skb_dest)->decoded) {
1168                 /* skb_src recoded and skb_dest is newly coded */
1169                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1170                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1171                                    skb_src->len + ETH_HLEN);
1172                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1173                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1174                                    skb_dest->len + ETH_HLEN);
1175         } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1176                    BATADV_SKB_CB(skb_dest)->decoded) {
1177                 /* skb_src is newly coded and skb_dest is recoded */
1178                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1179                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1180                                    skb_src->len + ETH_HLEN);
1181                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1182                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1183                                    skb_dest->len + ETH_HLEN);
1184         }
1185
1186         /* skb_src is now coded into skb_dest, so free it */
1187         kfree_skb(skb_src);
1188
1189         /* avoid duplicate free of skb from nc_packet */
1190         nc_packet->skb = NULL;
1191         batadv_nc_packet_free(nc_packet);
1192
1193         /* Send the coded packet and return true */
1194         batadv_send_skb_packet(skb_dest, neigh_node->if_incoming, first_dest);
1195         res = true;
1196 out:
1197         if (router_neigh)
1198                 batadv_neigh_node_free_ref(router_neigh);
1199         if (router_coding)
1200                 batadv_neigh_node_free_ref(router_coding);
1201         if (router_neigh_ifinfo)
1202                 batadv_neigh_ifinfo_free_ref(router_neigh_ifinfo);
1203         if (router_coding_ifinfo)
1204                 batadv_neigh_ifinfo_free_ref(router_coding_ifinfo);
1205         return res;
1206 }
1207
1208 /**
1209  * batadv_nc_skb_coding_possible - true if a decoded skb is available at dst.
1210  * @skb: data skb to forward
1211  * @dst: destination mac address of the other skb to code with
1212  * @src: source mac address of skb
1213  *
1214  * Whenever we network code a packet we have to check whether we received it in
1215  * a network coded form. If so, we may not be able to use it for coding because
1216  * some neighbors may also have received (overheard) the packet in the network
1217  * coded form without being able to decode it. It is hard to know which of the
1218  * neighboring nodes was able to decode the packet, therefore we can only
1219  * re-code the packet if the source of the previous encoded packet is involved.
1220  * Since the source encoded the packet we can be certain it has all necessary
1221  * decode information.
1222  *
1223  * Returns true if coding of a decoded packet is allowed.
1224  */
1225 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1226 {
1227         if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1228                 return false;
1229         return true;
1230 }
1231
1232 /**
1233  * batadv_nc_path_search - Find the coding path matching in_nc_node and
1234  *  out_nc_node to retrieve a buffered packet that can be used for coding.
1235  * @bat_priv: the bat priv with all the soft interface information
1236  * @in_nc_node: pointer to skb next hop's neighbor nc node
1237  * @out_nc_node: pointer to skb source's neighbor nc node
1238  * @skb: data skb to forward
1239  * @eth_dst: next hop mac address of skb
1240  *
1241  * Returns true if coding of a decoded skb is allowed.
1242  */
1243 static struct batadv_nc_packet *
1244 batadv_nc_path_search(struct batadv_priv *bat_priv,
1245                       struct batadv_nc_node *in_nc_node,
1246                       struct batadv_nc_node *out_nc_node,
1247                       struct sk_buff *skb,
1248                       u8 *eth_dst)
1249 {
1250         struct batadv_nc_path *nc_path, nc_path_key;
1251         struct batadv_nc_packet *nc_packet_out = NULL;
1252         struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1253         struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1254         int idx;
1255
1256         if (!hash)
1257                 return NULL;
1258
1259         /* Create almost path key */
1260         batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1261                                out_nc_node->addr);
1262         idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1263
1264         /* Check for coding opportunities in this nc_path */
1265         rcu_read_lock();
1266         hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1267                 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1268                         continue;
1269
1270                 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1271                         continue;
1272
1273                 spin_lock_bh(&nc_path->packet_list_lock);
1274                 if (list_empty(&nc_path->packet_list)) {
1275                         spin_unlock_bh(&nc_path->packet_list_lock);
1276                         continue;
1277                 }
1278
1279                 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1280                                          &nc_path->packet_list, list) {
1281                         if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1282                                                            eth_dst,
1283                                                            in_nc_node->addr))
1284                                 continue;
1285
1286                         /* Coding opportunity is found! */
1287                         list_del(&nc_packet->list);
1288                         nc_packet_out = nc_packet;
1289                         break;
1290                 }
1291
1292                 spin_unlock_bh(&nc_path->packet_list_lock);
1293                 break;
1294         }
1295         rcu_read_unlock();
1296
1297         return nc_packet_out;
1298 }
1299
1300 /**
1301  * batadv_nc_skb_src_search - Loops through the list of neighoring nodes of the
1302  *  skb's sender (may be equal to the originator).
1303  * @bat_priv: the bat priv with all the soft interface information
1304  * @skb: data skb to forward
1305  * @eth_dst: next hop mac address of skb
1306  * @eth_src: source mac address of skb
1307  * @in_nc_node: pointer to skb next hop's neighbor nc node
1308  *
1309  * Returns an nc packet if a suitable coding packet was found, NULL otherwise.
1310  */
1311 static struct batadv_nc_packet *
1312 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1313                          struct sk_buff *skb,
1314                          u8 *eth_dst,
1315                          u8 *eth_src,
1316                          struct batadv_nc_node *in_nc_node)
1317 {
1318         struct batadv_orig_node *orig_node;
1319         struct batadv_nc_node *out_nc_node;
1320         struct batadv_nc_packet *nc_packet = NULL;
1321
1322         orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1323         if (!orig_node)
1324                 return NULL;
1325
1326         rcu_read_lock();
1327         list_for_each_entry_rcu(out_nc_node,
1328                                 &orig_node->out_coding_list, list) {
1329                 /* Check if the skb is decoded and if recoding is possible */
1330                 if (!batadv_nc_skb_coding_possible(skb,
1331                                                    out_nc_node->addr, eth_src))
1332                         continue;
1333
1334                 /* Search for an opportunity in this nc_path */
1335                 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1336                                                   out_nc_node, skb, eth_dst);
1337                 if (nc_packet)
1338                         break;
1339         }
1340         rcu_read_unlock();
1341
1342         batadv_orig_node_free_ref(orig_node);
1343         return nc_packet;
1344 }
1345
1346 /**
1347  * batadv_nc_skb_store_before_coding - set the ethernet src and dst of the
1348  *  unicast skb before it is stored for use in later decoding
1349  * @bat_priv: the bat priv with all the soft interface information
1350  * @skb: data skb to store
1351  * @eth_dst_new: new destination mac address of skb
1352  */
1353 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1354                                               struct sk_buff *skb,
1355                                               u8 *eth_dst_new)
1356 {
1357         struct ethhdr *ethhdr;
1358
1359         /* Copy skb header to change the mac header */
1360         skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1361         if (!skb)
1362                 return;
1363
1364         /* Set the mac header as if we actually sent the packet uncoded */
1365         ethhdr = eth_hdr(skb);
1366         ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1367         ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1368
1369         /* Set data pointer to MAC header to mimic packets from our tx path */
1370         skb_push(skb, ETH_HLEN);
1371
1372         /* Add the packet to the decoding packet pool */
1373         batadv_nc_skb_store_for_decoding(bat_priv, skb);
1374
1375         /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1376          * our ref
1377          */
1378         kfree_skb(skb);
1379 }
1380
1381 /**
1382  * batadv_nc_skb_dst_search - Loops through list of neighboring nodes to dst.
1383  * @skb: data skb to forward
1384  * @neigh_node: next hop to forward packet to
1385  * @ethhdr: pointer to the ethernet header inside the skb
1386  *
1387  * Loops through list of neighboring nodes the next hop has a good connection to
1388  * (receives OGMs with a sufficient quality). We need to find a neighbor of our
1389  * next hop that potentially sent a packet which our next hop also received
1390  * (overheard) and has stored for later decoding.
1391  *
1392  * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1393  */
1394 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1395                                      struct batadv_neigh_node *neigh_node,
1396                                      struct ethhdr *ethhdr)
1397 {
1398         struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1399         struct batadv_priv *bat_priv = netdev_priv(netdev);
1400         struct batadv_orig_node *orig_node = neigh_node->orig_node;
1401         struct batadv_nc_node *nc_node;
1402         struct batadv_nc_packet *nc_packet = NULL;
1403
1404         rcu_read_lock();
1405         list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1406                 /* Search for coding opportunity with this in_nc_node */
1407                 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1408                                                      neigh_node->addr,
1409                                                      ethhdr->h_source, nc_node);
1410
1411                 /* Opportunity was found, so stop searching */
1412                 if (nc_packet)
1413                         break;
1414         }
1415         rcu_read_unlock();
1416
1417         if (!nc_packet)
1418                 return false;
1419
1420         /* Save packets for later decoding */
1421         batadv_nc_skb_store_before_coding(bat_priv, skb,
1422                                           neigh_node->addr);
1423         batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1424                                           nc_packet->neigh_node->addr);
1425
1426         /* Code and send packets */
1427         if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1428                                    neigh_node))
1429                 return true;
1430
1431         /* out of mem ? Coding failed - we have to free the buffered packet
1432          * to avoid memleaks. The skb passed as argument will be dealt with
1433          * by the calling function.
1434          */
1435         batadv_nc_send_packet(nc_packet);
1436         return false;
1437 }
1438
1439 /**
1440  * batadv_nc_skb_add_to_path - buffer skb for later encoding / decoding
1441  * @skb: skb to add to path
1442  * @nc_path: path to add skb to
1443  * @neigh_node: next hop to forward packet to
1444  * @packet_id: checksum to identify packet
1445  *
1446  * Returns true if the packet was buffered or false in case of an error.
1447  */
1448 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1449                                       struct batadv_nc_path *nc_path,
1450                                       struct batadv_neigh_node *neigh_node,
1451                                       __be32 packet_id)
1452 {
1453         struct batadv_nc_packet *nc_packet;
1454
1455         nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1456         if (!nc_packet)
1457                 return false;
1458
1459         /* Initialize nc_packet */
1460         nc_packet->timestamp = jiffies;
1461         nc_packet->packet_id = packet_id;
1462         nc_packet->skb = skb;
1463         nc_packet->neigh_node = neigh_node;
1464         nc_packet->nc_path = nc_path;
1465
1466         /* Add coding packet to list */
1467         spin_lock_bh(&nc_path->packet_list_lock);
1468         list_add_tail(&nc_packet->list, &nc_path->packet_list);
1469         spin_unlock_bh(&nc_path->packet_list_lock);
1470
1471         return true;
1472 }
1473
1474 /**
1475  * batadv_nc_skb_forward - try to code a packet or add it to the coding packet
1476  *  buffer
1477  * @skb: data skb to forward
1478  * @neigh_node: next hop to forward packet to
1479  *
1480  * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1481  */
1482 bool batadv_nc_skb_forward(struct sk_buff *skb,
1483                            struct batadv_neigh_node *neigh_node)
1484 {
1485         const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1486         struct batadv_priv *bat_priv = netdev_priv(netdev);
1487         struct batadv_unicast_packet *packet;
1488         struct batadv_nc_path *nc_path;
1489         struct ethhdr *ethhdr = eth_hdr(skb);
1490         __be32 packet_id;
1491         u8 *payload;
1492
1493         /* Check if network coding is enabled */
1494         if (!atomic_read(&bat_priv->network_coding))
1495                 goto out;
1496
1497         /* We only handle unicast packets */
1498         payload = skb_network_header(skb);
1499         packet = (struct batadv_unicast_packet *)payload;
1500         if (packet->packet_type != BATADV_UNICAST)
1501                 goto out;
1502
1503         /* Try to find a coding opportunity and send the skb if one is found */
1504         if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1505                 return true;
1506
1507         /* Find or create a nc_path for this src-dst pair */
1508         nc_path = batadv_nc_get_path(bat_priv,
1509                                      bat_priv->nc.coding_hash,
1510                                      ethhdr->h_source,
1511                                      neigh_node->addr);
1512
1513         if (!nc_path)
1514                 goto out;
1515
1516         /* Add skb to nc_path */
1517         packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1518         if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1519                 goto free_nc_path;
1520
1521         /* Packet is consumed */
1522         return true;
1523
1524 free_nc_path:
1525         batadv_nc_path_free_ref(nc_path);
1526 out:
1527         /* Packet is not consumed */
1528         return false;
1529 }
1530
1531 /**
1532  * batadv_nc_skb_store_for_decoding - save a clone of the skb which can be used
1533  *  when decoding coded packets
1534  * @bat_priv: the bat priv with all the soft interface information
1535  * @skb: data skb to store
1536  */
1537 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1538                                       struct sk_buff *skb)
1539 {
1540         struct batadv_unicast_packet *packet;
1541         struct batadv_nc_path *nc_path;
1542         struct ethhdr *ethhdr = eth_hdr(skb);
1543         __be32 packet_id;
1544         u8 *payload;
1545
1546         /* Check if network coding is enabled */
1547         if (!atomic_read(&bat_priv->network_coding))
1548                 goto out;
1549
1550         /* Check for supported packet type */
1551         payload = skb_network_header(skb);
1552         packet = (struct batadv_unicast_packet *)payload;
1553         if (packet->packet_type != BATADV_UNICAST)
1554                 goto out;
1555
1556         /* Find existing nc_path or create a new */
1557         nc_path = batadv_nc_get_path(bat_priv,
1558                                      bat_priv->nc.decoding_hash,
1559                                      ethhdr->h_source,
1560                                      ethhdr->h_dest);
1561
1562         if (!nc_path)
1563                 goto out;
1564
1565         /* Clone skb and adjust skb->data to point at batman header */
1566         skb = skb_clone(skb, GFP_ATOMIC);
1567         if (unlikely(!skb))
1568                 goto free_nc_path;
1569
1570         if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1571                 goto free_skb;
1572
1573         if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1574                 goto free_skb;
1575
1576         /* Add skb to nc_path */
1577         packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1578         if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1579                 goto free_skb;
1580
1581         batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1582         return;
1583
1584 free_skb:
1585         kfree_skb(skb);
1586 free_nc_path:
1587         batadv_nc_path_free_ref(nc_path);
1588 out:
1589         return;
1590 }
1591
1592 /**
1593  * batadv_nc_skb_store_sniffed_unicast - check if a received unicast packet
1594  *  should be saved in the decoding buffer and, if so, store it there
1595  * @bat_priv: the bat priv with all the soft interface information
1596  * @skb: unicast skb to store
1597  */
1598 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1599                                          struct sk_buff *skb)
1600 {
1601         struct ethhdr *ethhdr = eth_hdr(skb);
1602
1603         if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1604                 return;
1605
1606         /* Set data pointer to MAC header to mimic packets from our tx path */
1607         skb_push(skb, ETH_HLEN);
1608
1609         batadv_nc_skb_store_for_decoding(bat_priv, skb);
1610 }
1611
1612 /**
1613  * batadv_nc_skb_decode_packet - decode given skb using the decode data stored
1614  *  in nc_packet
1615  * @bat_priv: the bat priv with all the soft interface information
1616  * @skb: unicast skb to decode
1617  * @nc_packet: decode data needed to decode the skb
1618  *
1619  * Returns pointer to decoded unicast packet if the packet was decoded or NULL
1620  * in case of an error.
1621  */
1622 static struct batadv_unicast_packet *
1623 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1624                             struct batadv_nc_packet *nc_packet)
1625 {
1626         const int h_size = sizeof(struct batadv_unicast_packet);
1627         const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1628         struct batadv_unicast_packet *unicast_packet;
1629         struct batadv_coded_packet coded_packet_tmp;
1630         struct ethhdr *ethhdr, ethhdr_tmp;
1631         u8 *orig_dest, ttl, ttvn;
1632         unsigned int coding_len;
1633         int err;
1634
1635         /* Save headers temporarily */
1636         memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1637         memcpy(&ethhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1638
1639         if (skb_cow(skb, 0) < 0)
1640                 return NULL;
1641
1642         if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1643                 return NULL;
1644
1645         /* Data points to batman header, so set mac header 14 bytes before
1646          * and network to data
1647          */
1648         skb_set_mac_header(skb, -ETH_HLEN);
1649         skb_reset_network_header(skb);
1650
1651         /* Reconstruct original mac header */
1652         ethhdr = eth_hdr(skb);
1653         *ethhdr = ethhdr_tmp;
1654
1655         /* Select the correct unicast header information based on the location
1656          * of our mac address in the coded_packet header
1657          */
1658         if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1659                 /* If we are the second destination the packet was overheard,
1660                  * so the Ethernet address must be copied to h_dest and
1661                  * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1662                  */
1663                 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1664                 skb->pkt_type = PACKET_HOST;
1665
1666                 orig_dest = coded_packet_tmp.second_orig_dest;
1667                 ttl = coded_packet_tmp.second_ttl;
1668                 ttvn = coded_packet_tmp.second_ttvn;
1669         } else {
1670                 orig_dest = coded_packet_tmp.first_orig_dest;
1671                 ttl = coded_packet_tmp.ttl;
1672                 ttvn = coded_packet_tmp.first_ttvn;
1673         }
1674
1675         coding_len = ntohs(coded_packet_tmp.coded_len);
1676
1677         if (coding_len > skb->len)
1678                 return NULL;
1679
1680         /* Here the magic is reversed:
1681          *   extract the missing packet from the received coded packet
1682          */
1683         batadv_nc_memxor(skb->data + h_size,
1684                          nc_packet->skb->data + h_size,
1685                          coding_len);
1686
1687         /* Resize decoded skb if decoded with larger packet */
1688         if (nc_packet->skb->len > coding_len + h_size) {
1689                 err = pskb_trim_rcsum(skb, coding_len + h_size);
1690                 if (err)
1691                         return NULL;
1692         }
1693
1694         /* Create decoded unicast packet */
1695         unicast_packet = (struct batadv_unicast_packet *)skb->data;
1696         unicast_packet->packet_type = BATADV_UNICAST;
1697         unicast_packet->version = BATADV_COMPAT_VERSION;
1698         unicast_packet->ttl = ttl;
1699         ether_addr_copy(unicast_packet->dest, orig_dest);
1700         unicast_packet->ttvn = ttvn;
1701
1702         batadv_nc_packet_free(nc_packet);
1703         return unicast_packet;
1704 }
1705
1706 /**
1707  * batadv_nc_find_decoding_packet - search through buffered decoding data to
1708  *  find the data needed to decode the coded packet
1709  * @bat_priv: the bat priv with all the soft interface information
1710  * @ethhdr: pointer to the ethernet header inside the coded packet
1711  * @coded: coded packet we try to find decode data for
1712  *
1713  * Returns pointer to nc packet if the needed data was found or NULL otherwise.
1714  */
1715 static struct batadv_nc_packet *
1716 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1717                                struct ethhdr *ethhdr,
1718                                struct batadv_coded_packet *coded)
1719 {
1720         struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1721         struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1722         struct batadv_nc_path *nc_path, nc_path_key;
1723         u8 *dest, *source;
1724         __be32 packet_id;
1725         int index;
1726
1727         if (!hash)
1728                 return NULL;
1729
1730         /* Select the correct packet id based on the location of our mac-addr */
1731         dest = ethhdr->h_source;
1732         if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1733                 source = coded->second_source;
1734                 packet_id = coded->second_crc;
1735         } else {
1736                 source = coded->first_source;
1737                 packet_id = coded->first_crc;
1738         }
1739
1740         batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1741         index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1742
1743         /* Search for matching coding path */
1744         rcu_read_lock();
1745         hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1746                 /* Find matching nc_packet */
1747                 spin_lock_bh(&nc_path->packet_list_lock);
1748                 list_for_each_entry(tmp_nc_packet,
1749                                     &nc_path->packet_list, list) {
1750                         if (packet_id == tmp_nc_packet->packet_id) {
1751                                 list_del(&tmp_nc_packet->list);
1752
1753                                 nc_packet = tmp_nc_packet;
1754                                 break;
1755                         }
1756                 }
1757                 spin_unlock_bh(&nc_path->packet_list_lock);
1758
1759                 if (nc_packet)
1760                         break;
1761         }
1762         rcu_read_unlock();
1763
1764         if (!nc_packet)
1765                 batadv_dbg(BATADV_DBG_NC, bat_priv,
1766                            "No decoding packet found for %u\n", packet_id);
1767
1768         return nc_packet;
1769 }
1770
1771 /**
1772  * batadv_nc_recv_coded_packet - try to decode coded packet and enqueue the
1773  *  resulting unicast packet
1774  * @skb: incoming coded packet
1775  * @recv_if: pointer to interface this packet was received on
1776  */
1777 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1778                                        struct batadv_hard_iface *recv_if)
1779 {
1780         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1781         struct batadv_unicast_packet *unicast_packet;
1782         struct batadv_coded_packet *coded_packet;
1783         struct batadv_nc_packet *nc_packet;
1784         struct ethhdr *ethhdr;
1785         int hdr_size = sizeof(*coded_packet);
1786
1787         /* Check if network coding is enabled */
1788         if (!atomic_read(&bat_priv->network_coding))
1789                 return NET_RX_DROP;
1790
1791         /* Make sure we can access (and remove) header */
1792         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1793                 return NET_RX_DROP;
1794
1795         coded_packet = (struct batadv_coded_packet *)skb->data;
1796         ethhdr = eth_hdr(skb);
1797
1798         /* Verify frame is destined for us */
1799         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1800             !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1801                 return NET_RX_DROP;
1802
1803         /* Update stat counter */
1804         if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1805                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1806
1807         nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1808                                                    coded_packet);
1809         if (!nc_packet) {
1810                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1811                 return NET_RX_DROP;
1812         }
1813
1814         /* Make skb's linear, because decoding accesses the entire buffer */
1815         if (skb_linearize(skb) < 0)
1816                 goto free_nc_packet;
1817
1818         if (skb_linearize(nc_packet->skb) < 0)
1819                 goto free_nc_packet;
1820
1821         /* Decode the packet */
1822         unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1823         if (!unicast_packet) {
1824                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1825                 goto free_nc_packet;
1826         }
1827
1828         /* Mark packet as decoded to do correct recoding when forwarding */
1829         BATADV_SKB_CB(skb)->decoded = true;
1830         batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1831         batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1832                            skb->len + ETH_HLEN);
1833         return batadv_recv_unicast_packet(skb, recv_if);
1834
1835 free_nc_packet:
1836         batadv_nc_packet_free(nc_packet);
1837         return NET_RX_DROP;
1838 }
1839
1840 /**
1841  * batadv_nc_mesh_free - clean up network coding memory
1842  * @bat_priv: the bat priv with all the soft interface information
1843  */
1844 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1845 {
1846         batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1847         batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1848         cancel_delayed_work_sync(&bat_priv->nc.work);
1849
1850         batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1851         batadv_hash_destroy(bat_priv->nc.coding_hash);
1852         batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1853         batadv_hash_destroy(bat_priv->nc.decoding_hash);
1854 }
1855
1856 /**
1857  * batadv_nc_nodes_seq_print_text - print the nc node information
1858  * @seq: seq file to print on
1859  * @offset: not used
1860  */
1861 int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
1862 {
1863         struct net_device *net_dev = (struct net_device *)seq->private;
1864         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1865         struct batadv_hashtable *hash = bat_priv->orig_hash;
1866         struct batadv_hard_iface *primary_if;
1867         struct hlist_head *head;
1868         struct batadv_orig_node *orig_node;
1869         struct batadv_nc_node *nc_node;
1870         int i;
1871
1872         primary_if = batadv_seq_print_text_primary_if_get(seq);
1873         if (!primary_if)
1874                 goto out;
1875
1876         /* Traverse list of originators */
1877         for (i = 0; i < hash->size; i++) {
1878                 head = &hash->table[i];
1879
1880                 /* For each orig_node in this bin */
1881                 rcu_read_lock();
1882                 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1883                         /* no need to print the orig node if it does not have
1884                          * network coding neighbors
1885                          */
1886                         if (list_empty(&orig_node->in_coding_list) &&
1887                             list_empty(&orig_node->out_coding_list))
1888                                 continue;
1889
1890                         seq_printf(seq, "Node:      %pM\n", orig_node->orig);
1891
1892                         seq_puts(seq, " Ingoing:  ");
1893                         /* For each in_nc_node to this orig_node */
1894                         list_for_each_entry_rcu(nc_node,
1895                                                 &orig_node->in_coding_list,
1896                                                 list)
1897                                 seq_printf(seq, "%pM ",
1898                                            nc_node->addr);
1899                         seq_puts(seq, "\n");
1900
1901                         seq_puts(seq, " Outgoing: ");
1902                         /* For out_nc_node to this orig_node */
1903                         list_for_each_entry_rcu(nc_node,
1904                                                 &orig_node->out_coding_list,
1905                                                 list)
1906                                 seq_printf(seq, "%pM ",
1907                                            nc_node->addr);
1908                         seq_puts(seq, "\n\n");
1909                 }
1910                 rcu_read_unlock();
1911         }
1912
1913 out:
1914         if (primary_if)
1915                 batadv_hardif_free_ref(primary_if);
1916         return 0;
1917 }
1918
1919 /**
1920  * batadv_nc_init_debugfs - create nc folder and related files in debugfs
1921  * @bat_priv: the bat priv with all the soft interface information
1922  */
1923 int batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
1924 {
1925         struct dentry *nc_dir, *file;
1926
1927         nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
1928         if (!nc_dir)
1929                 goto out;
1930
1931         file = debugfs_create_u8("min_tq", S_IRUGO | S_IWUSR, nc_dir,
1932                                  &bat_priv->nc.min_tq);
1933         if (!file)
1934                 goto out;
1935
1936         file = debugfs_create_u32("max_fwd_delay", S_IRUGO | S_IWUSR, nc_dir,
1937                                   &bat_priv->nc.max_fwd_delay);
1938         if (!file)
1939                 goto out;
1940
1941         file = debugfs_create_u32("max_buffer_time", S_IRUGO | S_IWUSR, nc_dir,
1942                                   &bat_priv->nc.max_buffer_time);
1943         if (!file)
1944                 goto out;
1945
1946         return 0;
1947
1948 out:
1949         return -ENOMEM;
1950 }