net/batman-adv/network-coding.c

   1 /* Copyright (C) 2012-2013 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, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA
  18  */
  19
  20 #include <linux/debugfs.h>
  21
  22 #include "main.h"
  23 #include "hash.h"
  24 #include "network-coding.h"
  25 #include "send.h"
  26 #include "originator.h"
  27 #include "hard-interface.h"
  28 #include "routing.h"
  29
  30 static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
  31 static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
  32
  33 static void batadv_nc_worker(struct work_struct *work);
  34 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
  35                                        struct batadv_hard_iface *recv_if);
  36
  37 /**
  38  * batadv_nc_start_timer - initialise the nc periodic worker
  39  * @bat_priv: the bat priv with all the soft interface information
  40  */
  41 static void batadv_nc_start_timer(struct batadv_priv *bat_priv)
  42 {
  43         queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work,
  44                            msecs_to_jiffies(10));
  45 }
  46
  47 /**
  48  * batadv_nc_init - initialise coding hash table and start house keeping
  49  * @bat_priv: the bat priv with all the soft interface information
  50  */
  51 int batadv_nc_init(struct batadv_priv *bat_priv)
  52 {
  53         bat_priv->nc.timestamp_fwd_flush = jiffies;
  54         bat_priv->nc.timestamp_sniffed_purge = jiffies;
  55
  56         if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
  57                 return 0;
  58
  59         bat_priv->nc.coding_hash = batadv_hash_new(128);
  60         if (!bat_priv->nc.coding_hash)
  61                 goto err;
  62
  63         batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
  64                                    &batadv_nc_coding_hash_lock_class_key);
  65
  66         bat_priv->nc.decoding_hash = batadv_hash_new(128);
  67         if (!bat_priv->nc.decoding_hash)
  68                 goto err;
  69
  70         batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
  71                                    &batadv_nc_decoding_hash_lock_class_key);
  72
  73         /* Register our packet type */
  74         if (batadv_recv_handler_register(BATADV_CODED,
  75                                          batadv_nc_recv_coded_packet) < 0)
  76                 goto err;
  77
  78         INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
  79         batadv_nc_start_timer(bat_priv);
  80
  81         return 0;
  82
  83 err:
  84         return -ENOMEM;
  85 }
  86
  87 /**
  88  * batadv_nc_init_bat_priv - initialise the nc specific bat_priv variables
  89  * @bat_priv: the bat priv with all the soft interface information
  90  */
  91 void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
  92 {
  93         atomic_set(&bat_priv->network_coding, 1);
  94         bat_priv->nc.min_tq = 200;
  95         bat_priv->nc.max_fwd_delay = 10;
  96         bat_priv->nc.max_buffer_time = 200;
  97 }
  98
  99 /**
 100  * batadv_nc_init_orig - initialise the nc fields of an orig_node
 101  * @orig_node: the orig_node which is going to be initialised
 102  */
 103 void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
 104 {
 105         INIT_LIST_HEAD(&orig_node->in_coding_list);
 106         INIT_LIST_HEAD(&orig_node->out_coding_list);
 107         spin_lock_init(&orig_node->in_coding_list_lock);
 108         spin_lock_init(&orig_node->out_coding_list_lock);
 109 }
 110
 111 /**
 112  * batadv_nc_node_free_rcu - rcu callback to free an nc node and remove
 113  *  its refcount on the orig_node
 114  * @rcu: rcu pointer of the nc node
 115  */
 116 static void batadv_nc_node_free_rcu(struct rcu_head *rcu)
 117 {
 118         struct batadv_nc_node *nc_node;
 119
 120         nc_node = container_of(rcu, struct batadv_nc_node, rcu);
 121         batadv_orig_node_free_ref(nc_node->orig_node);
 122         kfree(nc_node);
 123 }
 124
 125 /**
 126  * batadv_nc_node_free_ref - decrements the nc node refcounter and possibly
 127  * frees it
 128  * @nc_node: the nc node to free
 129  */
 130 static void batadv_nc_node_free_ref(struct batadv_nc_node *nc_node)
 131 {
 132         if (atomic_dec_and_test(&nc_node->refcount))
 133                 call_rcu(&nc_node->rcu, batadv_nc_node_free_rcu);
 134 }
 135
 136 /**
 137  * batadv_nc_path_free_ref - decrements the nc path refcounter and possibly
 138  * frees it
 139  * @nc_path: the nc node to free
 140  */
 141 static void batadv_nc_path_free_ref(struct batadv_nc_path *nc_path)
 142 {
 143         if (atomic_dec_and_test(&nc_path->refcount))
 144                 kfree_rcu(nc_path, rcu);
 145 }
 146
 147 /**
 148  * batadv_nc_packet_free - frees nc packet
 149  * @nc_packet: the nc packet to free
 150  */
 151 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet)
 152 {
 153         if (nc_packet->skb)
 154                 kfree_skb(nc_packet->skb);
 155
 156         batadv_nc_path_free_ref(nc_packet->nc_path);
 157         kfree(nc_packet);
 158 }
 159
 160 /**
 161  * batadv_nc_to_purge_nc_node - checks whether an nc node has to be purged
 162  * @bat_priv: the bat priv with all the soft interface information
 163  * @nc_node: the nc node to check
 164  *
 165  * Returns true if the entry has to be purged now, false otherwise
 166  */
 167 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
 168                                        struct batadv_nc_node *nc_node)
 169 {
 170         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 171                 return true;
 172
 173         return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
 174 }
 175
 176 /**
 177  * batadv_nc_to_purge_nc_path_coding - checks whether an nc path has timed out
 178  * @bat_priv: the bat priv with all the soft interface information
 179  * @nc_path: the nc path to check
 180  *
 181  * Returns true if the entry has to be purged now, false otherwise
 182  */
 183 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
 184                                               struct batadv_nc_path *nc_path)
 185 {
 186         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 187                 return true;
 188
 189         /* purge the path when no packets has been added for 10 times the
 190          * max_fwd_delay time
 191          */
 192         return batadv_has_timed_out(nc_path->last_valid,
 193                                     bat_priv->nc.max_fwd_delay * 10);
 194 }
 195
 196 /**
 197  * batadv_nc_to_purge_nc_path_decoding - checks whether an nc path has timed out
 198  * @bat_priv: the bat priv with all the soft interface information
 199  * @nc_path: the nc path to check
 200  *
 201  * Returns true if the entry has to be purged now, false otherwise
 202  */
 203 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
 204                                                 struct batadv_nc_path *nc_path)
 205 {
 206         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
 207                 return true;
 208
 209         /* purge the path when no packets has been added for 10 times the
 210          * max_buffer time
 211          */
 212         return batadv_has_timed_out(nc_path->last_valid,
 213                                     bat_priv->nc.max_buffer_time*10);
 214 }
 215
 216 /**
 217  * batadv_nc_purge_orig_nc_nodes - go through list of nc nodes and purge stale
 218  *  entries
 219  * @bat_priv: the bat priv with all the soft interface information
 220  * @list: list of nc nodes
 221  * @lock: nc node list lock
 222  * @to_purge: function in charge to decide whether an entry has to be purged or
 223  *            not. This function takes the nc node as argument and has to return
 224  *            a boolean value: true if the entry has to be deleted, false
 225  *            otherwise
 226  */
 227 static void
 228 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
 229                               struct list_head *list,
 230                               spinlock_t *lock,
 231                               bool (*to_purge)(struct batadv_priv *,
 232                                                struct batadv_nc_node *))
 233 {
 234         struct batadv_nc_node *nc_node, *nc_node_tmp;
 235
 236         /* For each nc_node in list */
 237         spin_lock_bh(lock);
 238         list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
 239                 /* if an helper function has been passed as parameter,
 240                  * ask it if the entry has to be purged or not
 241                  */
 242                 if (to_purge && !to_purge(bat_priv, nc_node))
 243                         continue;
 244
 245                 batadv_dbg(BATADV_DBG_NC, bat_priv,
 246                            "Removing nc_node %pM -> %pM\n",
 247                            nc_node->addr, nc_node->orig_node->orig);
 248                 list_del_rcu(&nc_node->list);
 249                 batadv_nc_node_free_ref(nc_node);
 250         }
 251         spin_unlock_bh(lock);
 252 }
 253
 254 /**
 255  * batadv_nc_purge_orig - purges all nc node data attached of the given
 256  *  originator
 257  * @bat_priv: the bat priv with all the soft interface information
 258  * @orig_node: orig_node with the nc node entries to be purged
 259  * @to_purge: function in charge to decide whether an entry has to be purged or
 260  *            not. This function takes the nc node as argument and has to return
 261  *            a boolean value: true is the entry has to be deleted, false
 262  *            otherwise
 263  */
 264 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
 265                           struct batadv_orig_node *orig_node,
 266                           bool (*to_purge)(struct batadv_priv *,
 267                                            struct batadv_nc_node *))
 268 {
 269         /* Check ingoing nc_node's of this orig_node */
 270         batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
 271                                       &orig_node->in_coding_list_lock,
 272                                       to_purge);
 273
 274         /* Check outgoing nc_node's of this orig_node */
 275         batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
 276                                       &orig_node->out_coding_list_lock,
 277                                       to_purge);
 278 }
 279
 280 /**
 281  * batadv_nc_purge_orig_hash - traverse entire originator hash to check if they
 282  *  have timed out nc nodes
 283  * @bat_priv: the bat priv with all the soft interface information
 284  */
 285 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
 286 {
 287         struct batadv_hashtable *hash = bat_priv->orig_hash;
 288         struct hlist_head *head;
 289         struct batadv_orig_node *orig_node;
 290         uint32_t i;
 291
 292         if (!hash)
 293                 return;
 294
 295         /* For each orig_node */
 296         for (i = 0; i < hash->size; i++) {
 297                 head = &hash->table[i];
 298
 299                 rcu_read_lock();
 300                 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
 301                         batadv_nc_purge_orig(bat_priv, orig_node,
 302                                              batadv_nc_to_purge_nc_node);
 303                 rcu_read_unlock();
 304         }
 305 }
 306
 307 /**
 308  * batadv_nc_purge_paths - traverse all nc paths part of the hash and remove
 309  *  unused ones
 310  * @bat_priv: the bat priv with all the soft interface information
 311  * @hash: hash table containing the nc paths to check
 312  * @to_purge: function in charge to decide whether an entry has to be purged or
 313  *            not. This function takes the nc node as argument and has to return
 314  *            a boolean value: true is the entry has to be deleted, false
 315  *            otherwise
 316  */
 317 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
 318                                   struct batadv_hashtable *hash,
 319                                   bool (*to_purge)(struct batadv_priv *,
 320                                                    struct batadv_nc_path *))
 321 {
 322         struct hlist_head *head;
 323         struct hlist_node *node_tmp;
 324         struct batadv_nc_path *nc_path;
 325         spinlock_t *lock; /* Protects lists in hash */
 326         uint32_t i;
 327
 328         for (i = 0; i < hash->size; i++) {
 329                 head = &hash->table[i];
 330                 lock = &hash->list_locks[i];
 331
 332                 /* For each nc_path in this bin */
 333                 spin_lock_bh(lock);
 334                 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
 335                         /* if an helper function has been passed as parameter,
 336                          * ask it if the entry has to be purged or not
 337                          */
 338                         if (to_purge && !to_purge(bat_priv, nc_path))
 339                                 continue;
 340
 341                         /* purging an non-empty nc_path should never happen, but
 342                          * is observed under high CPU load. Delay the purging
 343                          * until next iteration to allow the packet_list to be
 344                          * emptied first.
 345                          */
 346                         if (!unlikely(list_empty(&nc_path->packet_list))) {
 347                                 net_ratelimited_function(printk,
 348                                                          KERN_WARNING
 349                                                          "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
 350                                                          nc_path->prev_hop,
 351                                                          nc_path->next_hop);
 352                                 continue;
 353                         }
 354
 355                         /* nc_path is unused, so remove it */
 356                         batadv_dbg(BATADV_DBG_NC, bat_priv,
 357                                    "Remove nc_path %pM -> %pM\n",
 358                                    nc_path->prev_hop, nc_path->next_hop);
 359                         hlist_del_rcu(&nc_path->hash_entry);
 360                         batadv_nc_path_free_ref(nc_path);
 361                 }
 362                 spin_unlock_bh(lock);
 363         }
 364 }
 365
 366 /**
 367  * batadv_nc_hash_key_gen - computes the nc_path hash key
 368  * @key: buffer to hold the final hash key
 369  * @src: source ethernet mac address going into the hash key
 370  * @dst: destination ethernet mac address going into the hash key
 371  */
 372 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
 373                                    const char *dst)
 374 {
 375         memcpy(key->prev_hop, src, sizeof(key->prev_hop));
 376         memcpy(key->next_hop, dst, sizeof(key->next_hop));
 377 }
 378
 379 /**
 380  * batadv_nc_hash_choose - compute the hash value for an nc path
 381  * @data: data to hash
 382  * @size: size of the hash table
 383  *
 384  * Returns the selected index in the hash table for the given data.
 385  */
 386 static uint32_t batadv_nc_hash_choose(const void *data, uint32_t size)
 387 {
 388         const struct batadv_nc_path *nc_path = data;
 389         uint32_t hash = 0;
 390
 391         hash = batadv_hash_bytes(hash, &nc_path->prev_hop,
 392                                  sizeof(nc_path->prev_hop));
 393         hash = batadv_hash_bytes(hash, &nc_path->next_hop,
 394                                  sizeof(nc_path->next_hop));
 395
 396         hash += (hash << 3);
 397         hash ^= (hash >> 11);
 398         hash += (hash << 15);
 399
 400         return hash % size;
 401 }
 402
 403 /**
 404  * batadv_nc_hash_compare - comparing function used in the network coding hash
 405  *  tables
 406  * @node: node in the local table
 407  * @data2: second object to compare the node to
 408  *
 409  * Returns 1 if the two entry are the same, 0 otherwise
 410  */
 411 static int batadv_nc_hash_compare(const struct hlist_node *node,
 412                                   const void *data2)
 413 {
 414         const struct batadv_nc_path *nc_path1, *nc_path2;
 415
 416         nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
 417         nc_path2 = data2;
 418
 419         /* Return 1 if the two keys are identical */
 420         if (memcmp(nc_path1->prev_hop, nc_path2->prev_hop,
 421                    sizeof(nc_path1->prev_hop)) != 0)
 422                 return 0;
 423
 424         if (memcmp(nc_path1->next_hop, nc_path2->next_hop,
 425                    sizeof(nc_path1->next_hop)) != 0)
 426                 return 0;
 427
 428         return 1;
 429 }
 430
 431 /**
 432  * batadv_nc_hash_find - search for an existing nc path and return it
 433  * @hash: hash table containing the nc path
 434  * @data: search key
 435  *
 436  * Returns the nc_path if found, NULL otherwise.
 437  */
 438 static struct batadv_nc_path *
 439 batadv_nc_hash_find(struct batadv_hashtable *hash,
 440                     void *data)
 441 {
 442         struct hlist_head *head;
 443         struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
 444         int index;
 445
 446         if (!hash)
 447                 return NULL;
 448
 449         index = batadv_nc_hash_choose(data, hash->size);
 450         head = &hash->table[index];
 451
 452         rcu_read_lock();
 453         hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
 454                 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
 455                         continue;
 456
 457                 if (!atomic_inc_not_zero(&nc_path->refcount))
 458                         continue;
 459
 460                 nc_path_tmp = nc_path;
 461                 break;
 462         }
 463         rcu_read_unlock();
 464
 465         return nc_path_tmp;
 466 }
 467
 468 /**
 469  * batadv_nc_send_packet - send non-coded packet and free nc_packet struct
 470  * @nc_packet: the nc packet to send
 471  */
 472 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
 473 {
 474         batadv_send_skb_packet(nc_packet->skb,
 475                                nc_packet->neigh_node->if_incoming,
 476                                nc_packet->nc_path->next_hop);
 477         nc_packet->skb = NULL;
 478         batadv_nc_packet_free(nc_packet);
 479 }
 480
 481 /**
 482  * batadv_nc_sniffed_purge - Checks timestamp of given sniffed nc_packet.
 483  * @bat_priv: the bat priv with all the soft interface information
 484  * @nc_path: the nc path the packet belongs to
 485  * @nc_packet: the nc packet to be checked
 486  *
 487  * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
 488  * timeout. If so, the packet is no longer kept and the entry deleted from the
 489  * queue. Has to be called with the appropriate locks.
 490  *
 491  * Returns false as soon as the entry in the fifo queue has not been timed out
 492  * yet and true otherwise.
 493  */
 494 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
 495                                     struct batadv_nc_path *nc_path,
 496                                     struct batadv_nc_packet *nc_packet)
 497 {
 498         unsigned long timeout = bat_priv->nc.max_buffer_time;
 499         bool res = false;
 500
 501         /* Packets are added to tail, so the remaining packets did not time
 502          * out and we can stop processing the current queue
 503          */
 504         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
 505             !batadv_has_timed_out(nc_packet->timestamp, timeout))
 506                 goto out;
 507
 508         /* purge nc packet */
 509         list_del(&nc_packet->list);
 510         batadv_nc_packet_free(nc_packet);
 511
 512         res = true;
 513
 514 out:
 515         return res;
 516 }
 517
 518 /**
 519  * batadv_nc_fwd_flush - Checks the timestamp of the given nc packet.
 520  * @bat_priv: the bat priv with all the soft interface information
 521  * @nc_path: the nc path the packet belongs to
 522  * @nc_packet: the nc packet to be checked
 523  *
 524  * Checks whether the given nc packet has hit its forward timeout. If so, the
 525  * packet is no longer delayed, immediately sent and the entry deleted from the
 526  * queue. Has to be called with the appropriate locks.
 527  *
 528  * Returns false as soon as the entry in the fifo queue has not been timed out
 529  * yet and true otherwise.
 530  */
 531 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
 532                                 struct batadv_nc_path *nc_path,
 533                                 struct batadv_nc_packet *nc_packet)
 534 {
 535         unsigned long timeout = bat_priv->nc.max_fwd_delay;
 536
 537         /* Packets are added to tail, so the remaining packets did not time
 538          * out and we can stop processing the current queue
 539          */
 540         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
 541             !batadv_has_timed_out(nc_packet->timestamp, timeout))
 542                 return false;
 543
 544         /* Send packet */
 545         batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
 546         batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
 547                            nc_packet->skb->len + ETH_HLEN);
 548         list_del(&nc_packet->list);
 549         batadv_nc_send_packet(nc_packet);
 550
 551         return true;
 552 }
 553
 554 /**
 555  * batadv_nc_process_nc_paths - traverse given nc packet pool and free timed out
 556  *  nc packets
 557  * @bat_priv: the bat priv with all the soft interface information
 558  * @hash: to be processed hash table
 559  * @process_fn: Function called to process given nc packet. Should return true
 560  *              to encourage this function to proceed with the next packet.
 561  *              Otherwise the rest of the current queue is skipped.
 562  */
 563 static void
 564 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
 565                            struct batadv_hashtable *hash,
 566                            bool (*process_fn)(struct batadv_priv *,
 567                                               struct batadv_nc_path *,
 568                                               struct batadv_nc_packet *))
 569 {
 570         struct hlist_head *head;
 571         struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
 572         struct batadv_nc_path *nc_path;
 573         bool ret;
 574         int i;
 575
 576         if (!hash)
 577                 return;
 578
 579         /* Loop hash table bins */
 580         for (i = 0; i < hash->size; i++) {
 581                 head = &hash->table[i];
 582
 583                 /* Loop coding paths */
 584                 rcu_read_lock();
 585                 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
 586                         /* Loop packets */
 587                         spin_lock_bh(&nc_path->packet_list_lock);
 588                         list_for_each_entry_safe(nc_packet, nc_packet_tmp,
 589                                                  &nc_path->packet_list, list) {
 590                                 ret = process_fn(bat_priv, nc_path, nc_packet);
 591                                 if (!ret)
 592                                         break;
 593                         }
 594                         spin_unlock_bh(&nc_path->packet_list_lock);
 595                 }
 596                 rcu_read_unlock();
 597         }
 598 }
 599
 600 /**
 601  * batadv_nc_worker - periodic task for house keeping related to network coding
 602  * @work: kernel work struct
 603  */
 604 static void batadv_nc_worker(struct work_struct *work)
 605 {
 606         struct delayed_work *delayed_work;
 607         struct batadv_priv_nc *priv_nc;
 608         struct batadv_priv *bat_priv;
 609         unsigned long timeout;
 610
 611         delayed_work = container_of(work, struct delayed_work, work);
 612         priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
 613         bat_priv = container_of(priv_nc, struct batadv_priv, nc);
 614
 615         batadv_nc_purge_orig_hash(bat_priv);
 616         batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
 617                               batadv_nc_to_purge_nc_path_coding);
 618         batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
 619                               batadv_nc_to_purge_nc_path_decoding);
 620
 621         timeout = bat_priv->nc.max_fwd_delay;
 622
 623         if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
 624                 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
 625                                            batadv_nc_fwd_flush);
 626                 bat_priv->nc.timestamp_fwd_flush = jiffies;
 627         }
 628
 629         if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
 630                                  bat_priv->nc.max_buffer_time)) {
 631                 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
 632                                            batadv_nc_sniffed_purge);
 633                 bat_priv->nc.timestamp_sniffed_purge = jiffies;
 634         }
 635
 636         /* Schedule a new check */
 637         batadv_nc_start_timer(bat_priv);
 638 }
 639
 640 /**
 641  * batadv_can_nc_with_orig - checks whether the given orig node is suitable for
 642  *  coding or not
 643  * @bat_priv: the bat priv with all the soft interface information
 644  * @orig_node: neighboring orig node which may be used as nc candidate
 645  * @ogm_packet: incoming ogm packet also used for the checks
 646  *
 647  * Returns true if:
 648  *  1) The OGM must have the most recent sequence number.
 649  *  2) The TTL must be decremented by one and only one.
 650  *  3) The OGM must be received from the first hop from orig_node.
 651  *  4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
 652  */
 653 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
 654                                     struct batadv_orig_node *orig_node,
 655                                     struct batadv_ogm_packet *ogm_packet)
 656 {
 657         if (orig_node->last_real_seqno != ntohl(ogm_packet->seqno))
 658                 return false;
 659         if (orig_node->last_ttl != ogm_packet->header.ttl + 1)
 660                 return false;
 661         if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
 662                 return false;
 663         if (ogm_packet->tq < bat_priv->nc.min_tq)
 664                 return false;
 665
 666         return true;
 667 }
 668
 669 /**
 670  * batadv_nc_find_nc_node - search for an existing nc node and return it
 671  * @orig_node: orig node originating the ogm packet
 672  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
 673  *  (can be equal to orig_node)
 674  * @in_coding: traverse incoming or outgoing network coding list
 675  *
 676  * Returns the nc_node if found, NULL otherwise.
 677  */
 678 static struct batadv_nc_node
 679 *batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
 680                         struct batadv_orig_node *orig_neigh_node,
 681                         bool in_coding)
 682 {
 683         struct batadv_nc_node *nc_node, *nc_node_out = NULL;
 684         struct list_head *list;
 685
 686         if (in_coding)
 687                 list = &orig_neigh_node->in_coding_list;
 688         else
 689                 list = &orig_neigh_node->out_coding_list;
 690
 691         /* Traverse list of nc_nodes to orig_node */
 692         rcu_read_lock();
 693         list_for_each_entry_rcu(nc_node, list, list) {
 694                 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
 695                         continue;
 696
 697                 if (!atomic_inc_not_zero(&nc_node->refcount))
 698                         continue;
 699
 700                 /* Found a match */
 701                 nc_node_out = nc_node;
 702                 break;
 703         }
 704         rcu_read_unlock();
 705
 706         return nc_node_out;
 707 }
 708
 709 /**
 710  * batadv_nc_get_nc_node - retrieves an nc node or creates the entry if it was
 711  *  not found
 712  * @bat_priv: the bat priv with all the soft interface information
 713  * @orig_node: orig node originating the ogm packet
 714  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
 715  *  (can be equal to orig_node)
 716  * @in_coding: traverse incoming or outgoing network coding list
 717  *
 718  * Returns the nc_node if found or created, NULL in case of an error.
 719  */
 720 static struct batadv_nc_node
 721 *batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
 722                        struct batadv_orig_node *orig_node,
 723                        struct batadv_orig_node *orig_neigh_node,
 724                        bool in_coding)
 725 {
 726         struct batadv_nc_node *nc_node;
 727         spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
 728         struct list_head *list;
 729
 730         /* Check if nc_node is already added */
 731         nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
 732
 733         /* Node found */
 734         if (nc_node)
 735                 return nc_node;
 736
 737         nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
 738         if (!nc_node)
 739                 return NULL;
 740
 741         if (!atomic_inc_not_zero(&orig_neigh_node->refcount))
 742                 goto free;
 743
 744         /* Initialize nc_node */
 745         INIT_LIST_HEAD(&nc_node->list);
 746         memcpy(nc_node->addr, orig_node->orig, ETH_ALEN);
 747         nc_node->orig_node = orig_neigh_node;
 748         atomic_set(&nc_node->refcount, 2);
 749
 750         /* Select ingoing or outgoing coding node */
 751         if (in_coding) {
 752                 lock = &orig_neigh_node->in_coding_list_lock;
 753                 list = &orig_neigh_node->in_coding_list;
 754         } else {
 755                 lock = &orig_neigh_node->out_coding_list_lock;
 756                 list = &orig_neigh_node->out_coding_list;
 757         }
 758
 759         batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
 760                    nc_node->addr, nc_node->orig_node->orig);
 761
 762         /* Add nc_node to orig_node */
 763         spin_lock_bh(lock);
 764         list_add_tail_rcu(&nc_node->list, list);
 765         spin_unlock_bh(lock);
 766
 767         return nc_node;
 768
 769 free:
 770         kfree(nc_node);
 771         return NULL;
 772 }
 773
 774 /**
 775  * batadv_nc_update_nc_node - updates stored incoming and outgoing nc node structs
 776  *  (best called on incoming OGMs)
 777  * @bat_priv: the bat priv with all the soft interface information
 778  * @orig_node: orig node originating the ogm packet
 779  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
 780  *  (can be equal to orig_node)
 781  * @ogm_packet: incoming ogm packet
 782  * @is_single_hop_neigh: orig_node is a single hop neighbor
 783  */
 784 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
 785                               struct batadv_orig_node *orig_node,
 786                               struct batadv_orig_node *orig_neigh_node,
 787                               struct batadv_ogm_packet *ogm_packet,
 788                               int is_single_hop_neigh)
 789 {
 790         struct batadv_nc_node *in_nc_node = NULL, *out_nc_node = NULL;
 791
 792         /* Check if network coding is enabled */
 793         if (!atomic_read(&bat_priv->network_coding))
 794                 goto out;
 795
 796         /* accept ogms from 'good' neighbors and single hop neighbors */
 797         if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
 798             !is_single_hop_neigh)
 799                 goto out;
 800
 801         /* Add orig_node as in_nc_node on hop */
 802         in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
 803                                            orig_neigh_node, true);
 804         if (!in_nc_node)
 805                 goto out;
 806
 807         in_nc_node->last_seen = jiffies;
 808
 809         /* Add hop as out_nc_node on orig_node */
 810         out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
 811                                             orig_node, false);
 812         if (!out_nc_node)
 813                 goto out;
 814
 815         out_nc_node->last_seen = jiffies;
 816
 817 out:
 818         if (in_nc_node)
 819                 batadv_nc_node_free_ref(in_nc_node);
 820         if (out_nc_node)
 821                 batadv_nc_node_free_ref(out_nc_node);
 822 }
 823
 824 /**
 825  * batadv_nc_get_path - get existing nc_path or allocate a new one
 826  * @bat_priv: the bat priv with all the soft interface information
 827  * @hash: hash table containing the nc path
 828  * @src: ethernet source address - first half of the nc path search key
 829  * @dst: ethernet destination address - second half of the nc path search key
 830  *
 831  * Returns pointer to nc_path if the path was found or created, returns NULL
 832  * on error.
 833  */
 834 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
 835                                                  struct batadv_hashtable *hash,
 836                                                  uint8_t *src,
 837                                                  uint8_t *dst)
 838 {
 839         int hash_added;
 840         struct batadv_nc_path *nc_path, nc_path_key;
 841
 842         batadv_nc_hash_key_gen(&nc_path_key, src, dst);
 843
 844         /* Search for existing nc_path */
 845         nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
 846
 847         if (nc_path) {
 848                 /* Set timestamp to delay removal of nc_path */
 849                 nc_path->last_valid = jiffies;
 850                 return nc_path;
 851         }
 852
 853         /* No existing nc_path was found; create a new */
 854         nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
 855
 856         if (!nc_path)
 857                 return NULL;
 858
 859         /* Initialize nc_path */
 860         INIT_LIST_HEAD(&nc_path->packet_list);
 861         spin_lock_init(&nc_path->packet_list_lock);
 862         atomic_set(&nc_path->refcount, 2);
 863         nc_path->last_valid = jiffies;
 864         memcpy(nc_path->next_hop, dst, ETH_ALEN);
 865         memcpy(nc_path->prev_hop, src, ETH_ALEN);
 866
 867         batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
 868                    nc_path->prev_hop,
 869                    nc_path->next_hop);
 870
 871         /* Add nc_path to hash table */
 872         hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
 873                                      batadv_nc_hash_choose, &nc_path_key,
 874                                      &nc_path->hash_entry);
 875
 876         if (hash_added < 0) {
 877                 kfree(nc_path);
 878                 return NULL;
 879         }
 880
 881         return nc_path;
 882 }
 883
 884 /**
 885  * batadv_nc_random_weight_tq - scale the receivers TQ-value to avoid unfair
 886  *  selection of a receiver with slightly lower TQ than the other
 887  * @tq: to be weighted tq value
 888  */
 889 static uint8_t batadv_nc_random_weight_tq(uint8_t tq)
 890 {
 891         uint8_t rand_val, rand_tq;
 892
 893         get_random_bytes(&rand_val, sizeof(rand_val));
 894
 895         /* randomize the estimated packet loss (max TQ - estimated TQ) */
 896         rand_tq = rand_val * (BATADV_TQ_MAX_VALUE - tq);
 897
 898         /* normalize the randomized packet loss */
 899         rand_tq /= BATADV_TQ_MAX_VALUE;
 900
 901         /* convert to (randomized) estimated tq again */
 902         return BATADV_TQ_MAX_VALUE - rand_tq;
 903 }
 904
 905 /**
 906  * batadv_nc_memxor - XOR destination with source
 907  * @dst: byte array to XOR into
 908  * @src: byte array to XOR from
 909  * @len: length of destination array
 910  */
 911 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
 912 {
 913         unsigned int i;
 914
 915         for (i = 0; i < len; ++i)
 916                 dst[i] ^= src[i];
 917 }
 918
 919 /**
 920  * batadv_nc_code_packets - code a received unicast_packet with an nc packet
 921  *  into a coded_packet and send it
 922  * @bat_priv: the bat priv with all the soft interface information
 923  * @skb: data skb to forward
 924  * @ethhdr: pointer to the ethernet header inside the skb
 925  * @nc_packet: structure containing the packet to the skb can be coded with
 926  * @neigh_node: next hop to forward packet to
 927  *
 928  * Returns true if both packets are consumed, false otherwise.
 929  */
 930 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
 931                                    struct sk_buff *skb,
 932                                    struct ethhdr *ethhdr,
 933                                    struct batadv_nc_packet *nc_packet,
 934                                    struct batadv_neigh_node *neigh_node)
 935 {
 936         uint8_t tq_weighted_neigh, tq_weighted_coding;
 937         struct sk_buff *skb_dest, *skb_src;
 938         struct batadv_unicast_packet *packet1;
 939         struct batadv_unicast_packet *packet2;
 940         struct batadv_coded_packet *coded_packet;
 941         struct batadv_neigh_node *neigh_tmp, *router_neigh;
 942         struct batadv_neigh_node *router_coding = NULL;
 943         uint8_t *first_source, *first_dest, *second_source, *second_dest;
 944         __be32 packet_id1, packet_id2;
 945         size_t count;
 946         bool res = false;
 947         int coding_len;
 948         int unicast_size = sizeof(*packet1);
 949         int coded_size = sizeof(*coded_packet);
 950         int header_add = coded_size - unicast_size;
 951
 952         router_neigh = batadv_orig_node_get_router(neigh_node->orig_node);
 953         if (!router_neigh)
 954                 goto out;
 955
 956         neigh_tmp = nc_packet->neigh_node;
 957         router_coding = batadv_orig_node_get_router(neigh_tmp->orig_node);
 958         if (!router_coding)
 959                 goto out;
 960
 961         tq_weighted_neigh = batadv_nc_random_weight_tq(router_neigh->tq_avg);
 962         tq_weighted_coding = batadv_nc_random_weight_tq(router_coding->tq_avg);
 963
 964         /* Select one destination for the MAC-header dst-field based on
 965          * weighted TQ-values.
 966          */
 967         if (tq_weighted_neigh >= tq_weighted_coding) {
 968                 /* Destination from nc_packet is selected for MAC-header */
 969                 first_dest = nc_packet->nc_path->next_hop;
 970                 first_source = nc_packet->nc_path->prev_hop;
 971                 second_dest = neigh_node->addr;
 972                 second_source = ethhdr->h_source;
 973                 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
 974                 packet2 = (struct batadv_unicast_packet *)skb->data;
 975                 packet_id1 = nc_packet->packet_id;
 976                 packet_id2 = batadv_skb_crc32(skb,
 977                                               skb->data + sizeof(*packet2));
 978         } else {
 979                 /* Destination for skb is selected for MAC-header */
 980                 first_dest = neigh_node->addr;
 981                 first_source = ethhdr->h_source;
 982                 second_dest = nc_packet->nc_path->next_hop;
 983                 second_source = nc_packet->nc_path->prev_hop;
 984                 packet1 = (struct batadv_unicast_packet *)skb->data;
 985                 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
 986                 packet_id1 = batadv_skb_crc32(skb,
 987                                               skb->data + sizeof(*packet1));
 988                 packet_id2 = nc_packet->packet_id;
 989         }
 990
 991         /* Instead of zero padding the smallest data buffer, we
 992          * code into the largest.
 993          */
 994         if (skb->len <= nc_packet->skb->len) {
 995                 skb_dest = nc_packet->skb;
 996                 skb_src = skb;
 997         } else {
 998                 skb_dest = skb;
 999                 skb_src = nc_packet->skb;
1000         }
1001
1002         /* coding_len is used when decoding the packet shorter packet */
1003         coding_len = skb_src->len - unicast_size;
1004
1005         if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1006                 goto out;
1007
1008         skb_push(skb_dest, header_add);
1009
1010         coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1011         skb_reset_mac_header(skb_dest);
1012
1013         coded_packet->header.packet_type = BATADV_CODED;
1014         coded_packet->header.version = BATADV_COMPAT_VERSION;
1015         coded_packet->header.ttl = packet1->header.ttl;
1016
1017         /* Info about first unicast packet */
1018         memcpy(coded_packet->first_source, first_source, ETH_ALEN);
1019         memcpy(coded_packet->first_orig_dest, packet1->dest, ETH_ALEN);
1020         coded_packet->first_crc = packet_id1;
1021         coded_packet->first_ttvn = packet1->ttvn;
1022
1023         /* Info about second unicast packet */
1024         memcpy(coded_packet->second_dest, second_dest, ETH_ALEN);
1025         memcpy(coded_packet->second_source, second_source, ETH_ALEN);
1026         memcpy(coded_packet->second_orig_dest, packet2->dest, ETH_ALEN);
1027         coded_packet->second_crc = packet_id2;
1028         coded_packet->second_ttl = packet2->header.ttl;
1029         coded_packet->second_ttvn = packet2->ttvn;
1030         coded_packet->coded_len = htons(coding_len);
1031
1032         /* This is where the magic happens: Code skb_src into skb_dest */
1033         batadv_nc_memxor(skb_dest->data + coded_size,
1034                          skb_src->data + unicast_size, coding_len);
1035
1036         /* Update counters accordingly */
1037         if (BATADV_SKB_CB(skb_src)->decoded &&
1038             BATADV_SKB_CB(skb_dest)->decoded) {
1039                 /* Both packets are recoded */
1040                 count = skb_src->len + ETH_HLEN;
1041                 count += skb_dest->len + ETH_HLEN;
1042                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1043                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1044         } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1045                    !BATADV_SKB_CB(skb_dest)->decoded) {
1046                 /* Both packets are newly coded */
1047                 count = skb_src->len + ETH_HLEN;
1048                 count += skb_dest->len + ETH_HLEN;
1049                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1050                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1051         } else if (BATADV_SKB_CB(skb_src)->decoded &&
1052                    !BATADV_SKB_CB(skb_dest)->decoded) {
1053                 /* skb_src recoded and skb_dest is newly coded */
1054                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1055                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1056                                    skb_src->len + ETH_HLEN);
1057                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1058                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1059                                    skb_dest->len + ETH_HLEN);
1060         } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1061                    BATADV_SKB_CB(skb_dest)->decoded) {
1062                 /* skb_src is newly coded and skb_dest is recoded */
1063                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1064                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1065                                    skb_src->len + ETH_HLEN);
1066                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1067                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1068                                    skb_dest->len + ETH_HLEN);
1069         }
1070
1071         /* skb_src is now coded into skb_dest, so free it */
1072         kfree_skb(skb_src);
1073
1074         /* avoid duplicate free of skb from nc_packet */
1075         nc_packet->skb = NULL;
1076         batadv_nc_packet_free(nc_packet);
1077
1078         /* Send the coded packet and return true */
1079         batadv_send_skb_packet(skb_dest, neigh_node->if_incoming, first_dest);
1080         res = true;
1081 out:
1082         if (router_neigh)
1083                 batadv_neigh_node_free_ref(router_neigh);
1084         if (router_coding)
1085                 batadv_neigh_node_free_ref(router_coding);
1086         return res;
1087 }
1088
1089 /**
1090  * batadv_nc_skb_coding_possible - true if a decoded skb is available at dst.
1091  * @skb: data skb to forward
1092  * @dst: destination mac address of the other skb to code with
1093  * @src: source mac address of skb
1094  *
1095  * Whenever we network code a packet we have to check whether we received it in
1096  * a network coded form. If so, we may not be able to use it for coding because
1097  * some neighbors may also have received (overheard) the packet in the network
1098  * coded form without being able to decode it. It is hard to know which of the
1099  * neighboring nodes was able to decode the packet, therefore we can only
1100  * re-code the packet if the source of the previous encoded packet is involved.
1101  * Since the source encoded the packet we can be certain it has all necessary
1102  * decode information.
1103  *
1104  * Returns true if coding of a decoded packet is allowed.
1105  */
1106 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb,
1107                                           uint8_t *dst, uint8_t *src)
1108 {
1109         if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1110                 return false;
1111         else
1112                 return true;
1113 }
1114
1115 /**
1116  * batadv_nc_path_search - Find the coding path matching in_nc_node and
1117  *  out_nc_node to retrieve a buffered packet that can be used for coding.
1118  * @bat_priv: the bat priv with all the soft interface information
1119  * @in_nc_node: pointer to skb next hop's neighbor nc node
1120  * @out_nc_node: pointer to skb source's neighbor nc node
1121  * @skb: data skb to forward
1122  * @eth_dst: next hop mac address of skb
1123  *
1124  * Returns true if coding of a decoded skb is allowed.
1125  */
1126 static struct batadv_nc_packet *
1127 batadv_nc_path_search(struct batadv_priv *bat_priv,
1128                       struct batadv_nc_node *in_nc_node,
1129                       struct batadv_nc_node *out_nc_node,
1130                       struct sk_buff *skb,
1131                       uint8_t *eth_dst)
1132 {
1133         struct batadv_nc_path *nc_path, nc_path_key;
1134         struct batadv_nc_packet *nc_packet_out = NULL;
1135         struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1136         struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1137         int idx;
1138
1139         if (!hash)
1140                 return NULL;
1141
1142         /* Create almost path key */
1143         batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1144                                out_nc_node->addr);
1145         idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1146
1147         /* Check for coding opportunities in this nc_path */
1148         rcu_read_lock();
1149         hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1150                 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1151                         continue;
1152
1153                 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1154                         continue;
1155
1156                 spin_lock_bh(&nc_path->packet_list_lock);
1157                 if (list_empty(&nc_path->packet_list)) {
1158                         spin_unlock_bh(&nc_path->packet_list_lock);
1159                         continue;
1160                 }
1161
1162                 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1163                                          &nc_path->packet_list, list) {
1164                         if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1165                                                            eth_dst,
1166                                                            in_nc_node->addr))
1167                                 continue;
1168
1169                         /* Coding opportunity is found! */
1170                         list_del(&nc_packet->list);
1171                         nc_packet_out = nc_packet;
1172                         break;
1173                 }
1174
1175                 spin_unlock_bh(&nc_path->packet_list_lock);
1176                 break;
1177         }
1178         rcu_read_unlock();
1179
1180         return nc_packet_out;
1181 }
1182
1183 /**
1184  * batadv_nc_skb_src_search - Loops through the list of neighoring nodes of the
1185  *  skb's sender (may be equal to the originator).
1186  * @bat_priv: the bat priv with all the soft interface information
1187  * @skb: data skb to forward
1188  * @eth_dst: next hop mac address of skb
1189  * @eth_src: source mac address of skb
1190  * @in_nc_node: pointer to skb next hop's neighbor nc node
1191  *
1192  * Returns an nc packet if a suitable coding packet was found, NULL otherwise.
1193  */
1194 static struct batadv_nc_packet *
1195 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1196                          struct sk_buff *skb,
1197                          uint8_t *eth_dst,
1198                          uint8_t *eth_src,
1199                          struct batadv_nc_node *in_nc_node)
1200 {
1201         struct batadv_orig_node *orig_node;
1202         struct batadv_nc_node *out_nc_node;
1203         struct batadv_nc_packet *nc_packet = NULL;
1204
1205         orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1206         if (!orig_node)
1207                 return NULL;
1208
1209         rcu_read_lock();
1210         list_for_each_entry_rcu(out_nc_node,
1211                                 &orig_node->out_coding_list, list) {
1212                 /* Check if the skb is decoded and if recoding is possible */
1213                 if (!batadv_nc_skb_coding_possible(skb,
1214                                                    out_nc_node->addr, eth_src))
1215                         continue;
1216
1217                 /* Search for an opportunity in this nc_path */
1218                 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1219                                                   out_nc_node, skb, eth_dst);
1220                 if (nc_packet)
1221                         break;
1222         }
1223         rcu_read_unlock();
1224
1225         batadv_orig_node_free_ref(orig_node);
1226         return nc_packet;
1227 }
1228
1229 /**
1230  * batadv_nc_skb_store_before_coding - set the ethernet src and dst of the
1231  *  unicast skb before it is stored for use in later decoding
1232  * @bat_priv: the bat priv with all the soft interface information
1233  * @skb: data skb to store
1234  * @eth_dst_new: new destination mac address of skb
1235  */
1236 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1237                                               struct sk_buff *skb,
1238                                               uint8_t *eth_dst_new)
1239 {
1240         struct ethhdr *ethhdr;
1241
1242         /* Copy skb header to change the mac header */
1243         skb = pskb_copy(skb, GFP_ATOMIC);
1244         if (!skb)
1245                 return;
1246
1247         /* Set the mac header as if we actually sent the packet uncoded */
1248         ethhdr = eth_hdr(skb);
1249         memcpy(ethhdr->h_source, ethhdr->h_dest, ETH_ALEN);
1250         memcpy(ethhdr->h_dest, eth_dst_new, ETH_ALEN);
1251
1252         /* Set data pointer to MAC header to mimic packets from our tx path */
1253         skb_push(skb, ETH_HLEN);
1254
1255         /* Add the packet to the decoding packet pool */
1256         batadv_nc_skb_store_for_decoding(bat_priv, skb);
1257
1258         /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1259          * our ref
1260          */
1261         kfree_skb(skb);
1262 }
1263
1264 /**
1265  * batadv_nc_skb_dst_search - Loops through list of neighboring nodes to dst.
1266  * @skb: data skb to forward
1267  * @neigh_node: next hop to forward packet to
1268  * @ethhdr: pointer to the ethernet header inside the skb
1269  *
1270  * Loops through list of neighboring nodes the next hop has a good connection to
1271  * (receives OGMs with a sufficient quality). We need to find a neighbor of our
1272  * next hop that potentially sent a packet which our next hop also received
1273  * (overheard) and has stored for later decoding.
1274  *
1275  * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1276  */
1277 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1278                                      struct batadv_neigh_node *neigh_node,
1279                                      struct ethhdr *ethhdr)
1280 {
1281         struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1282         struct batadv_priv *bat_priv = netdev_priv(netdev);
1283         struct batadv_orig_node *orig_node = neigh_node->orig_node;
1284         struct batadv_nc_node *nc_node;
1285         struct batadv_nc_packet *nc_packet = NULL;
1286
1287         rcu_read_lock();
1288         list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1289                 /* Search for coding opportunity with this in_nc_node */
1290                 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1291                                                      neigh_node->addr,
1292                                                      ethhdr->h_source, nc_node);
1293
1294                 /* Opportunity was found, so stop searching */
1295                 if (nc_packet)
1296                         break;
1297         }
1298         rcu_read_unlock();
1299
1300         if (!nc_packet)
1301                 return false;
1302
1303         /* Save packets for later decoding */
1304         batadv_nc_skb_store_before_coding(bat_priv, skb,
1305                                           neigh_node->addr);
1306         batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1307                                           nc_packet->neigh_node->addr);
1308
1309         /* Code and send packets */
1310         if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1311                                    neigh_node))
1312                 return true;
1313
1314         /* out of mem ? Coding failed - we have to free the buffered packet
1315          * to avoid memleaks. The skb passed as argument will be dealt with
1316          * by the calling function.
1317          */
1318         batadv_nc_send_packet(nc_packet);
1319         return false;
1320 }
1321
1322 /**
1323  * batadv_nc_skb_add_to_path - buffer skb for later encoding / decoding
1324  * @skb: skb to add to path
1325  * @nc_path: path to add skb to
1326  * @neigh_node: next hop to forward packet to
1327  * @packet_id: checksum to identify packet
1328  *
1329  * Returns true if the packet was buffered or false in case of an error.
1330  */
1331 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1332                                       struct batadv_nc_path *nc_path,
1333                                       struct batadv_neigh_node *neigh_node,
1334                                       __be32 packet_id)
1335 {
1336         struct batadv_nc_packet *nc_packet;
1337
1338         nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1339         if (!nc_packet)
1340                 return false;
1341
1342         /* Initialize nc_packet */
1343         nc_packet->timestamp = jiffies;
1344         nc_packet->packet_id = packet_id;
1345         nc_packet->skb = skb;
1346         nc_packet->neigh_node = neigh_node;
1347         nc_packet->nc_path = nc_path;
1348
1349         /* Add coding packet to list */
1350         spin_lock_bh(&nc_path->packet_list_lock);
1351         list_add_tail(&nc_packet->list, &nc_path->packet_list);
1352         spin_unlock_bh(&nc_path->packet_list_lock);
1353
1354         return true;
1355 }
1356
1357 /**
1358  * batadv_nc_skb_forward - try to code a packet or add it to the coding packet
1359  *  buffer
1360  * @skb: data skb to forward
1361  * @neigh_node: next hop to forward packet to
1362  *
1363  * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1364  */
1365 bool batadv_nc_skb_forward(struct sk_buff *skb,
1366                            struct batadv_neigh_node *neigh_node)
1367 {
1368         const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1369         struct batadv_priv *bat_priv = netdev_priv(netdev);
1370         struct batadv_unicast_packet *packet;
1371         struct batadv_nc_path *nc_path;
1372         struct ethhdr *ethhdr = eth_hdr(skb);
1373         __be32 packet_id;
1374         u8 *payload;
1375
1376         /* Check if network coding is enabled */
1377         if (!atomic_read(&bat_priv->network_coding))
1378                 goto out;
1379
1380         /* We only handle unicast packets */
1381         payload = skb_network_header(skb);
1382         packet = (struct batadv_unicast_packet *)payload;
1383         if (packet->header.packet_type != BATADV_UNICAST)
1384                 goto out;
1385
1386         /* Try to find a coding opportunity and send the skb if one is found */
1387         if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1388                 return true;
1389
1390         /* Find or create a nc_path for this src-dst pair */
1391         nc_path = batadv_nc_get_path(bat_priv,
1392                                      bat_priv->nc.coding_hash,
1393                                      ethhdr->h_source,
1394                                      neigh_node->addr);
1395
1396         if (!nc_path)
1397                 goto out;
1398
1399         /* Add skb to nc_path */
1400         packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1401         if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1402                 goto free_nc_path;
1403
1404         /* Packet is consumed */
1405         return true;
1406
1407 free_nc_path:
1408         batadv_nc_path_free_ref(nc_path);
1409 out:
1410         /* Packet is not consumed */
1411         return false;
1412 }
1413
1414 /**
1415  * batadv_nc_skb_store_for_decoding - save a clone of the skb which can be used
1416  *  when decoding coded packets
1417  * @bat_priv: the bat priv with all the soft interface information
1418  * @skb: data skb to store
1419  */
1420 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1421                                       struct sk_buff *skb)
1422 {
1423         struct batadv_unicast_packet *packet;
1424         struct batadv_nc_path *nc_path;
1425         struct ethhdr *ethhdr = eth_hdr(skb);
1426         __be32 packet_id;
1427         u8 *payload;
1428
1429         /* Check if network coding is enabled */
1430         if (!atomic_read(&bat_priv->network_coding))
1431                 goto out;
1432
1433         /* Check for supported packet type */
1434         payload = skb_network_header(skb);
1435         packet = (struct batadv_unicast_packet *)payload;
1436         if (packet->header.packet_type != BATADV_UNICAST)
1437                 goto out;
1438
1439         /* Find existing nc_path or create a new */
1440         nc_path = batadv_nc_get_path(bat_priv,
1441                                      bat_priv->nc.decoding_hash,
1442                                      ethhdr->h_source,
1443                                      ethhdr->h_dest);
1444
1445         if (!nc_path)
1446                 goto out;
1447
1448         /* Clone skb and adjust skb->data to point at batman header */
1449         skb = skb_clone(skb, GFP_ATOMIC);
1450         if (unlikely(!skb))
1451                 goto free_nc_path;
1452
1453         if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1454                 goto free_skb;
1455
1456         if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1457                 goto free_skb;
1458
1459         /* Add skb to nc_path */
1460         packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1461         if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1462                 goto free_skb;
1463
1464         batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1465         return;
1466
1467 free_skb:
1468         kfree_skb(skb);
1469 free_nc_path:
1470         batadv_nc_path_free_ref(nc_path);
1471 out:
1472         return;
1473 }
1474
1475 /**
1476  * batadv_nc_skb_store_sniffed_unicast - check if a received unicast packet
1477  *  should be saved in the decoding buffer and, if so, store it there
1478  * @bat_priv: the bat priv with all the soft interface information
1479  * @skb: unicast skb to store
1480  */
1481 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1482                                          struct sk_buff *skb)
1483 {
1484         struct ethhdr *ethhdr = eth_hdr(skb);
1485
1486         if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1487                 return;
1488
1489         /* Set data pointer to MAC header to mimic packets from our tx path */
1490         skb_push(skb, ETH_HLEN);
1491
1492         batadv_nc_skb_store_for_decoding(bat_priv, skb);
1493 }
1494
1495 /**
1496  * batadv_nc_skb_decode_packet - decode given skb using the decode data stored
1497  *  in nc_packet
1498  * @bat_priv: the bat priv with all the soft interface information
1499  * @skb: unicast skb to decode
1500  * @nc_packet: decode data needed to decode the skb
1501  *
1502  * Returns pointer to decoded unicast packet if the packet was decoded or NULL
1503  * in case of an error.
1504  */
1505 static struct batadv_unicast_packet *
1506 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1507                             struct batadv_nc_packet *nc_packet)
1508 {
1509         const int h_size = sizeof(struct batadv_unicast_packet);
1510         const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1511         struct batadv_unicast_packet *unicast_packet;
1512         struct batadv_coded_packet coded_packet_tmp;
1513         struct ethhdr *ethhdr, ethhdr_tmp;
1514         uint8_t *orig_dest, ttl, ttvn;
1515         unsigned int coding_len;
1516         int err;
1517
1518         /* Save headers temporarily */
1519         memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1520         memcpy(&ethhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1521
1522         if (skb_cow(skb, 0) < 0)
1523                 return NULL;
1524
1525         if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1526                 return NULL;
1527
1528         /* Data points to batman header, so set mac header 14 bytes before
1529          * and network to data
1530          */
1531         skb_set_mac_header(skb, -ETH_HLEN);
1532         skb_reset_network_header(skb);
1533
1534         /* Reconstruct original mac header */
1535         ethhdr = eth_hdr(skb);
1536         memcpy(ethhdr, &ethhdr_tmp, sizeof(*ethhdr));
1537
1538         /* Select the correct unicast header information based on the location
1539          * of our mac address in the coded_packet header
1540          */
1541         if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1542                 /* If we are the second destination the packet was overheard,
1543                  * so the Ethernet address must be copied to h_dest and
1544                  * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1545                  */
1546                 memcpy(ethhdr->h_dest, coded_packet_tmp.second_dest, ETH_ALEN);
1547                 skb->pkt_type = PACKET_HOST;
1548
1549                 orig_dest = coded_packet_tmp.second_orig_dest;
1550                 ttl = coded_packet_tmp.second_ttl;
1551                 ttvn = coded_packet_tmp.second_ttvn;
1552         } else {
1553                 orig_dest = coded_packet_tmp.first_orig_dest;
1554                 ttl = coded_packet_tmp.header.ttl;
1555                 ttvn = coded_packet_tmp.first_ttvn;
1556         }
1557
1558         coding_len = ntohs(coded_packet_tmp.coded_len);
1559
1560         if (coding_len > skb->len)
1561                 return NULL;
1562
1563         /* Here the magic is reversed:
1564          *   extract the missing packet from the received coded packet
1565          */
1566         batadv_nc_memxor(skb->data + h_size,
1567                          nc_packet->skb->data + h_size,
1568                          coding_len);
1569
1570         /* Resize decoded skb if decoded with larger packet */
1571         if (nc_packet->skb->len > coding_len + h_size) {
1572                 err = pskb_trim_rcsum(skb, coding_len + h_size);
1573                 if (err)
1574                         return NULL;
1575         }
1576
1577         /* Create decoded unicast packet */
1578         unicast_packet = (struct batadv_unicast_packet *)skb->data;
1579         unicast_packet->header.packet_type = BATADV_UNICAST;
1580         unicast_packet->header.version = BATADV_COMPAT_VERSION;
1581         unicast_packet->header.ttl = ttl;
1582         memcpy(unicast_packet->dest, orig_dest, ETH_ALEN);
1583         unicast_packet->ttvn = ttvn;
1584
1585         batadv_nc_packet_free(nc_packet);
1586         return unicast_packet;
1587 }
1588
1589 /**
1590  * batadv_nc_find_decoding_packet - search through buffered decoding data to
1591  *  find the data needed to decode the coded packet
1592  * @bat_priv: the bat priv with all the soft interface information
1593  * @ethhdr: pointer to the ethernet header inside the coded packet
1594  * @coded: coded packet we try to find decode data for
1595  *
1596  * Returns pointer to nc packet if the needed data was found or NULL otherwise.
1597  */
1598 static struct batadv_nc_packet *
1599 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1600                                struct ethhdr *ethhdr,
1601                                struct batadv_coded_packet *coded)
1602 {
1603         struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1604         struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1605         struct batadv_nc_path *nc_path, nc_path_key;
1606         uint8_t *dest, *source;
1607         __be32 packet_id;
1608         int index;
1609
1610         if (!hash)
1611                 return NULL;
1612
1613         /* Select the correct packet id based on the location of our mac-addr */
1614         dest = ethhdr->h_source;
1615         if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1616                 source = coded->second_source;
1617                 packet_id = coded->second_crc;
1618         } else {
1619                 source = coded->first_source;
1620                 packet_id = coded->first_crc;
1621         }
1622
1623         batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1624         index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1625
1626         /* Search for matching coding path */
1627         rcu_read_lock();
1628         hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1629                 /* Find matching nc_packet */
1630                 spin_lock_bh(&nc_path->packet_list_lock);
1631                 list_for_each_entry(tmp_nc_packet,
1632                                     &nc_path->packet_list, list) {
1633                         if (packet_id == tmp_nc_packet->packet_id) {
1634                                 list_del(&tmp_nc_packet->list);
1635
1636                                 nc_packet = tmp_nc_packet;
1637                                 break;
1638                         }
1639                 }
1640                 spin_unlock_bh(&nc_path->packet_list_lock);
1641
1642                 if (nc_packet)
1643                         break;
1644         }
1645         rcu_read_unlock();
1646
1647         if (!nc_packet)
1648                 batadv_dbg(BATADV_DBG_NC, bat_priv,
1649                            "No decoding packet found for %u\n", packet_id);
1650
1651         return nc_packet;
1652 }
1653
1654 /**
1655  * batadv_nc_recv_coded_packet - try to decode coded packet and enqueue the
1656  *  resulting unicast packet
1657  * @skb: incoming coded packet
1658  * @recv_if: pointer to interface this packet was received on
1659  */
1660 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1661                                        struct batadv_hard_iface *recv_if)
1662 {
1663         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1664         struct batadv_unicast_packet *unicast_packet;
1665         struct batadv_coded_packet *coded_packet;
1666         struct batadv_nc_packet *nc_packet;
1667         struct ethhdr *ethhdr;
1668         int hdr_size = sizeof(*coded_packet);
1669
1670         /* Check if network coding is enabled */
1671         if (!atomic_read(&bat_priv->network_coding))
1672                 return NET_RX_DROP;
1673
1674         /* Make sure we can access (and remove) header */
1675         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1676                 return NET_RX_DROP;
1677
1678         coded_packet = (struct batadv_coded_packet *)skb->data;
1679         ethhdr = eth_hdr(skb);
1680
1681         /* Verify frame is destined for us */
1682         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1683             !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1684                 return NET_RX_DROP;
1685
1686         /* Update stat counter */
1687         if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1688                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1689
1690         nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1691                                                    coded_packet);
1692         if (!nc_packet) {
1693                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1694                 return NET_RX_DROP;
1695         }
1696
1697         /* Make skb's linear, because decoding accesses the entire buffer */
1698         if (skb_linearize(skb) < 0)
1699                 goto free_nc_packet;
1700
1701         if (skb_linearize(nc_packet->skb) < 0)
1702                 goto free_nc_packet;
1703
1704         /* Decode the packet */
1705         unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1706         if (!unicast_packet) {
1707                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1708                 goto free_nc_packet;
1709         }
1710
1711         /* Mark packet as decoded to do correct recoding when forwarding */
1712         BATADV_SKB_CB(skb)->decoded = true;
1713         batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1714         batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1715                            skb->len + ETH_HLEN);
1716         return batadv_recv_unicast_packet(skb, recv_if);
1717
1718 free_nc_packet:
1719         batadv_nc_packet_free(nc_packet);
1720         return NET_RX_DROP;
1721 }
1722
1723 /**
1724  * batadv_nc_free - clean up network coding memory
1725  * @bat_priv: the bat priv with all the soft interface information
1726  */
1727 void batadv_nc_free(struct batadv_priv *bat_priv)
1728 {
1729         batadv_recv_handler_unregister(BATADV_CODED);
1730         cancel_delayed_work_sync(&bat_priv->nc.work);
1731
1732         batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1733         batadv_hash_destroy(bat_priv->nc.coding_hash);
1734         batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1735         batadv_hash_destroy(bat_priv->nc.decoding_hash);
1736 }
1737
1738 /**
1739  * batadv_nc_nodes_seq_print_text - print the nc node information
1740  * @seq: seq file to print on
1741  * @offset: not used
1742  */
1743 int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
1744 {
1745         struct net_device *net_dev = (struct net_device *)seq->private;
1746         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1747         struct batadv_hashtable *hash = bat_priv->orig_hash;
1748         struct batadv_hard_iface *primary_if;
1749         struct hlist_head *head;
1750         struct batadv_orig_node *orig_node;
1751         struct batadv_nc_node *nc_node;
1752         int i;
1753
1754         primary_if = batadv_seq_print_text_primary_if_get(seq);
1755         if (!primary_if)
1756                 goto out;
1757
1758         /* Traverse list of originators */
1759         for (i = 0; i < hash->size; i++) {
1760                 head = &hash->table[i];
1761
1762                 /* For each orig_node in this bin */
1763                 rcu_read_lock();
1764                 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1765                         /* no need to print the orig node if it does not have
1766                          * network coding neighbors
1767                          */
1768                         if (list_empty(&orig_node->in_coding_list) &&
1769                             list_empty(&orig_node->out_coding_list))
1770                                 continue;
1771
1772                         seq_printf(seq, "Node:      %pM\n", orig_node->orig);
1773
1774                         seq_puts(seq, " Ingoing:  ");
1775                         /* For each in_nc_node to this orig_node */
1776                         list_for_each_entry_rcu(nc_node,
1777                                                 &orig_node->in_coding_list,
1778                                                 list)
1779                                 seq_printf(seq, "%pM ",
1780                                            nc_node->addr);
1781                         seq_puts(seq, "\n");
1782
1783                         seq_puts(seq, " Outgoing: ");
1784                         /* For out_nc_node to this orig_node */
1785                         list_for_each_entry_rcu(nc_node,
1786                                                 &orig_node->out_coding_list,
1787                                                 list)
1788                                 seq_printf(seq, "%pM ",
1789                                            nc_node->addr);
1790                         seq_puts(seq, "\n\n");
1791                 }
1792                 rcu_read_unlock();
1793         }
1794
1795 out:
1796         if (primary_if)
1797                 batadv_hardif_free_ref(primary_if);
1798         return 0;
1799 }
1800
1801 /**
1802  * batadv_nc_init_debugfs - create nc folder and related files in debugfs
1803  * @bat_priv: the bat priv with all the soft interface information
1804  */
1805 int batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
1806 {
1807         struct dentry *nc_dir, *file;
1808
1809         nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
1810         if (!nc_dir)
1811                 goto out;
1812
1813         file = debugfs_create_u8("min_tq", S_IRUGO | S_IWUSR, nc_dir,
1814                                  &bat_priv->nc.min_tq);
1815         if (!file)
1816                 goto out;
1817
1818         file = debugfs_create_u32("max_fwd_delay", S_IRUGO | S_IWUSR, nc_dir,
1819                                   &bat_priv->nc.max_fwd_delay);
1820         if (!file)
1821                 goto out;
1822
1823         file = debugfs_create_u32("max_buffer_time", S_IRUGO | S_IWUSR, nc_dir,
1824                                   &bat_priv->nc.max_buffer_time);
1825         if (!file)
1826                 goto out;
1827
1828         return 0;
1829
1830 out:
1831         return -ENOMEM;
1832 }