kernel/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         /* Check if nc_node is already added */
 832         nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
 833
 834         /* Node found */
 835         if (nc_node)
 836                 return nc_node;
 837
 838         nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
 839         if (!nc_node)
 840                 return NULL;
 841
 842         if (!atomic_inc_not_zero(&orig_neigh_node->refcount))
 843                 goto free;
 844
 845         /* Initialize nc_node */
 846         INIT_LIST_HEAD(&nc_node->list);
 847         ether_addr_copy(nc_node->addr, orig_node->orig);
 848         nc_node->orig_node = orig_neigh_node;
 849         atomic_set(&nc_node->refcount, 2);
 850
 851         /* Select ingoing or outgoing coding node */
 852         if (in_coding) {
 853                 lock = &orig_neigh_node->in_coding_list_lock;
 854                 list = &orig_neigh_node->in_coding_list;
 855         } else {
 856                 lock = &orig_neigh_node->out_coding_list_lock;
 857                 list = &orig_neigh_node->out_coding_list;
 858         }
 859
 860         batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
 861                    nc_node->addr, nc_node->orig_node->orig);
 862
 863         /* Add nc_node to orig_node */
 864         spin_lock_bh(lock);
 865         list_add_tail_rcu(&nc_node->list, list);
 866         spin_unlock_bh(lock);
 867
 868         return nc_node;
 869
 870 free:
 871         kfree(nc_node);
 872         return NULL;
 873 }
 874
 875 /**
 876  * batadv_nc_update_nc_node - updates stored incoming and outgoing nc node
 877  *  structs (best called on incoming OGMs)
 878  * @bat_priv: the bat priv with all the soft interface information
 879  * @orig_node: orig node originating the ogm packet
 880  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
 881  *  (can be equal to orig_node)
 882  * @ogm_packet: incoming ogm packet
 883  * @is_single_hop_neigh: orig_node is a single hop neighbor
 884  */
 885 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
 886                               struct batadv_orig_node *orig_node,
 887                               struct batadv_orig_node *orig_neigh_node,
 888                               struct batadv_ogm_packet *ogm_packet,
 889                               int is_single_hop_neigh)
 890 {
 891         struct batadv_nc_node *in_nc_node = NULL;
 892         struct batadv_nc_node *out_nc_node = NULL;
 893
 894         /* Check if network coding is enabled */
 895         if (!atomic_read(&bat_priv->network_coding))
 896                 goto out;
 897
 898         /* check if orig node is network coding enabled */
 899         if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
 900                 goto out;
 901
 902         /* accept ogms from 'good' neighbors and single hop neighbors */
 903         if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
 904             !is_single_hop_neigh)
 905                 goto out;
 906
 907         /* Add orig_node as in_nc_node on hop */
 908         in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
 909                                            orig_neigh_node, true);
 910         if (!in_nc_node)
 911                 goto out;
 912
 913         in_nc_node->last_seen = jiffies;
 914
 915         /* Add hop as out_nc_node on orig_node */
 916         out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
 917                                             orig_node, false);
 918         if (!out_nc_node)
 919                 goto out;
 920
 921         out_nc_node->last_seen = jiffies;
 922
 923 out:
 924         if (in_nc_node)
 925                 batadv_nc_node_free_ref(in_nc_node);
 926         if (out_nc_node)
 927                 batadv_nc_node_free_ref(out_nc_node);
 928 }
 929
 930 /**
 931  * batadv_nc_get_path - get existing nc_path or allocate a new one
 932  * @bat_priv: the bat priv with all the soft interface information
 933  * @hash: hash table containing the nc path
 934  * @src: ethernet source address - first half of the nc path search key
 935  * @dst: ethernet destination address - second half of the nc path search key
 936  *
 937  * Returns pointer to nc_path if the path was found or created, returns NULL
 938  * on error.
 939  */
 940 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
 941                                                  struct batadv_hashtable *hash,
 942                                                  u8 *src,
 943                                                  u8 *dst)
 944 {
 945         int hash_added;
 946         struct batadv_nc_path *nc_path, nc_path_key;
 947
 948         batadv_nc_hash_key_gen(&nc_path_key, src, dst);
 949
 950         /* Search for existing nc_path */
 951         nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
 952
 953         if (nc_path) {
 954                 /* Set timestamp to delay removal of nc_path */
 955                 nc_path->last_valid = jiffies;
 956                 return nc_path;
 957         }
 958
 959         /* No existing nc_path was found; create a new */
 960         nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
 961
 962         if (!nc_path)
 963                 return NULL;
 964
 965         /* Initialize nc_path */
 966         INIT_LIST_HEAD(&nc_path->packet_list);
 967         spin_lock_init(&nc_path->packet_list_lock);
 968         atomic_set(&nc_path->refcount, 2);
 969         nc_path->last_valid = jiffies;
 970         ether_addr_copy(nc_path->next_hop, dst);
 971         ether_addr_copy(nc_path->prev_hop, src);
 972
 973         batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
 974                    nc_path->prev_hop,
 975                    nc_path->next_hop);
 976
 977         /* Add nc_path to hash table */
 978         hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
 979                                      batadv_nc_hash_choose, &nc_path_key,
 980                                      &nc_path->hash_entry);
 981
 982         if (hash_added < 0) {
 983                 kfree(nc_path);
 984                 return NULL;
 985         }
 986
 987         return nc_path;
 988 }
 989
 990 /**
 991  * batadv_nc_random_weight_tq - scale the receivers TQ-value to avoid unfair
 992  *  selection of a receiver with slightly lower TQ than the other
 993  * @tq: to be weighted tq value
 994  */
 995 static u8 batadv_nc_random_weight_tq(u8 tq)
 996 {
 997         u8 rand_val, rand_tq;
 998
 999         get_random_bytes(&rand_val, sizeof(rand_val));
1000
1001         /* randomize the estimated packet loss (max TQ - estimated TQ) */
1002         rand_tq = rand_val * (BATADV_TQ_MAX_VALUE - tq);
1003
1004         /* normalize the randomized packet loss */
1005         rand_tq /= BATADV_TQ_MAX_VALUE;
1006
1007         /* convert to (randomized) estimated tq again */
1008         return BATADV_TQ_MAX_VALUE - rand_tq;
1009 }
1010
1011 /**
1012  * batadv_nc_memxor - XOR destination with source
1013  * @dst: byte array to XOR into
1014  * @src: byte array to XOR from
1015  * @len: length of destination array
1016  */
1017 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
1018 {
1019         unsigned int i;
1020
1021         for (i = 0; i < len; ++i)
1022                 dst[i] ^= src[i];
1023 }
1024
1025 /**
1026  * batadv_nc_code_packets - code a received unicast_packet with an nc packet
1027  *  into a coded_packet and send it
1028  * @bat_priv: the bat priv with all the soft interface information
1029  * @skb: data skb to forward
1030  * @ethhdr: pointer to the ethernet header inside the skb
1031  * @nc_packet: structure containing the packet to the skb can be coded with
1032  * @neigh_node: next hop to forward packet to
1033  *
1034  * Returns true if both packets are consumed, false otherwise.
1035  */
1036 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1037                                    struct sk_buff *skb,
1038                                    struct ethhdr *ethhdr,
1039                                    struct batadv_nc_packet *nc_packet,
1040                                    struct batadv_neigh_node *neigh_node)
1041 {
1042         u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1043         struct sk_buff *skb_dest, *skb_src;
1044         struct batadv_unicast_packet *packet1;
1045         struct batadv_unicast_packet *packet2;
1046         struct batadv_coded_packet *coded_packet;
1047         struct batadv_neigh_node *neigh_tmp, *router_neigh;
1048         struct batadv_neigh_node *router_coding = NULL;
1049         struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1050         struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1051         u8 *first_source, *first_dest, *second_source, *second_dest;
1052         __be32 packet_id1, packet_id2;
1053         size_t count;
1054         bool res = false;
1055         int coding_len;
1056         int unicast_size = sizeof(*packet1);
1057         int coded_size = sizeof(*coded_packet);
1058         int header_add = coded_size - unicast_size;
1059
1060         /* TODO: do we need to consider the outgoing interface for
1061          * coded packets?
1062          */
1063         router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1064                                               BATADV_IF_DEFAULT);
1065         if (!router_neigh)
1066                 goto out;
1067
1068         router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1069                                                       BATADV_IF_DEFAULT);
1070         if (!router_neigh_ifinfo)
1071                 goto out;
1072
1073         neigh_tmp = nc_packet->neigh_node;
1074         router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1075                                                BATADV_IF_DEFAULT);
1076         if (!router_coding)
1077                 goto out;
1078
1079         router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1080                                                        BATADV_IF_DEFAULT);
1081         if (!router_coding_ifinfo)
1082                 goto out;
1083
1084         tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1085         tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1086         tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1087         tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1088
1089         /* Select one destination for the MAC-header dst-field based on
1090          * weighted TQ-values.
1091          */
1092         if (tq_weighted_neigh >= tq_weighted_coding) {
1093                 /* Destination from nc_packet is selected for MAC-header */
1094                 first_dest = nc_packet->nc_path->next_hop;
1095                 first_source = nc_packet->nc_path->prev_hop;
1096                 second_dest = neigh_node->addr;
1097                 second_source = ethhdr->h_source;
1098                 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1099                 packet2 = (struct batadv_unicast_packet *)skb->data;
1100                 packet_id1 = nc_packet->packet_id;
1101                 packet_id2 = batadv_skb_crc32(skb,
1102                                               skb->data + sizeof(*packet2));
1103         } else {
1104                 /* Destination for skb is selected for MAC-header */
1105                 first_dest = neigh_node->addr;
1106                 first_source = ethhdr->h_source;
1107                 second_dest = nc_packet->nc_path->next_hop;
1108                 second_source = nc_packet->nc_path->prev_hop;
1109                 packet1 = (struct batadv_unicast_packet *)skb->data;
1110                 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1111                 packet_id1 = batadv_skb_crc32(skb,
1112                                               skb->data + sizeof(*packet1));
1113                 packet_id2 = nc_packet->packet_id;
1114         }
1115
1116         /* Instead of zero padding the smallest data buffer, we
1117          * code into the largest.
1118          */
1119         if (skb->len <= nc_packet->skb->len) {
1120                 skb_dest = nc_packet->skb;
1121                 skb_src = skb;
1122         } else {
1123                 skb_dest = skb;
1124                 skb_src = nc_packet->skb;
1125         }
1126
1127         /* coding_len is used when decoding the packet shorter packet */
1128         coding_len = skb_src->len - unicast_size;
1129
1130         if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1131                 goto out;
1132
1133         skb_push(skb_dest, header_add);
1134
1135         coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1136         skb_reset_mac_header(skb_dest);
1137
1138         coded_packet->packet_type = BATADV_CODED;
1139         coded_packet->version = BATADV_COMPAT_VERSION;
1140         coded_packet->ttl = packet1->ttl;
1141
1142         /* Info about first unicast packet */
1143         ether_addr_copy(coded_packet->first_source, first_source);
1144         ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1145         coded_packet->first_crc = packet_id1;
1146         coded_packet->first_ttvn = packet1->ttvn;
1147
1148         /* Info about second unicast packet */
1149         ether_addr_copy(coded_packet->second_dest, second_dest);
1150         ether_addr_copy(coded_packet->second_source, second_source);
1151         ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1152         coded_packet->second_crc = packet_id2;
1153         coded_packet->second_ttl = packet2->ttl;
1154         coded_packet->second_ttvn = packet2->ttvn;
1155         coded_packet->coded_len = htons(coding_len);
1156
1157         /* This is where the magic happens: Code skb_src into skb_dest */
1158         batadv_nc_memxor(skb_dest->data + coded_size,
1159                          skb_src->data + unicast_size, coding_len);
1160
1161         /* Update counters accordingly */
1162         if (BATADV_SKB_CB(skb_src)->decoded &&
1163             BATADV_SKB_CB(skb_dest)->decoded) {
1164                 /* Both packets are recoded */
1165                 count = skb_src->len + ETH_HLEN;
1166                 count += skb_dest->len + ETH_HLEN;
1167                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1168                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1169         } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1170                    !BATADV_SKB_CB(skb_dest)->decoded) {
1171                 /* Both packets are newly coded */
1172                 count = skb_src->len + ETH_HLEN;
1173                 count += skb_dest->len + ETH_HLEN;
1174                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1175                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1176         } else if (BATADV_SKB_CB(skb_src)->decoded &&
1177                    !BATADV_SKB_CB(skb_dest)->decoded) {
1178                 /* skb_src recoded and skb_dest is newly coded */
1179                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1180                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1181                                    skb_src->len + ETH_HLEN);
1182                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1183                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1184                                    skb_dest->len + ETH_HLEN);
1185         } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1186                    BATADV_SKB_CB(skb_dest)->decoded) {
1187                 /* skb_src is newly coded and skb_dest is recoded */
1188                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1189                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1190                                    skb_src->len + ETH_HLEN);
1191                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1192                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1193                                    skb_dest->len + ETH_HLEN);
1194         }
1195
1196         /* skb_src is now coded into skb_dest, so free it */
1197         kfree_skb(skb_src);
1198
1199         /* avoid duplicate free of skb from nc_packet */
1200         nc_packet->skb = NULL;
1201         batadv_nc_packet_free(nc_packet);
1202
1203         /* Send the coded packet and return true */
1204         batadv_send_skb_packet(skb_dest, neigh_node->if_incoming, first_dest);
1205         res = true;
1206 out:
1207         if (router_neigh)
1208                 batadv_neigh_node_free_ref(router_neigh);
1209         if (router_coding)
1210                 batadv_neigh_node_free_ref(router_coding);
1211         if (router_neigh_ifinfo)
1212                 batadv_neigh_ifinfo_free_ref(router_neigh_ifinfo);
1213         if (router_coding_ifinfo)
1214                 batadv_neigh_ifinfo_free_ref(router_coding_ifinfo);
1215         return res;
1216 }
1217
1218 /**
1219  * batadv_nc_skb_coding_possible - true if a decoded skb is available at dst.
1220  * @skb: data skb to forward
1221  * @dst: destination mac address of the other skb to code with
1222  * @src: source mac address of skb
1223  *
1224  * Whenever we network code a packet we have to check whether we received it in
1225  * a network coded form. If so, we may not be able to use it for coding because
1226  * some neighbors may also have received (overheard) the packet in the network
1227  * coded form without being able to decode it. It is hard to know which of the
1228  * neighboring nodes was able to decode the packet, therefore we can only
1229  * re-code the packet if the source of the previous encoded packet is involved.
1230  * Since the source encoded the packet we can be certain it has all necessary
1231  * decode information.
1232  *
1233  * Returns true if coding of a decoded packet is allowed.
1234  */
1235 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1236 {
1237         if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1238                 return false;
1239         return true;
1240 }
1241
1242 /**
1243  * batadv_nc_path_search - Find the coding path matching in_nc_node and
1244  *  out_nc_node to retrieve a buffered packet that can be used for coding.
1245  * @bat_priv: the bat priv with all the soft interface information
1246  * @in_nc_node: pointer to skb next hop's neighbor nc node
1247  * @out_nc_node: pointer to skb source's neighbor nc node
1248  * @skb: data skb to forward
1249  * @eth_dst: next hop mac address of skb
1250  *
1251  * Returns true if coding of a decoded skb is allowed.
1252  */
1253 static struct batadv_nc_packet *
1254 batadv_nc_path_search(struct batadv_priv *bat_priv,
1255                       struct batadv_nc_node *in_nc_node,
1256                       struct batadv_nc_node *out_nc_node,
1257                       struct sk_buff *skb,
1258                       u8 *eth_dst)
1259 {
1260         struct batadv_nc_path *nc_path, nc_path_key;
1261         struct batadv_nc_packet *nc_packet_out = NULL;
1262         struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1263         struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1264         int idx;
1265
1266         if (!hash)
1267                 return NULL;
1268
1269         /* Create almost path key */
1270         batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1271                                out_nc_node->addr);
1272         idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1273
1274         /* Check for coding opportunities in this nc_path */
1275         rcu_read_lock();
1276         hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1277                 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1278                         continue;
1279
1280                 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1281                         continue;
1282
1283                 spin_lock_bh(&nc_path->packet_list_lock);
1284                 if (list_empty(&nc_path->packet_list)) {
1285                         spin_unlock_bh(&nc_path->packet_list_lock);
1286                         continue;
1287                 }
1288
1289                 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1290                                          &nc_path->packet_list, list) {
1291                         if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1292                                                            eth_dst,
1293                                                            in_nc_node->addr))
1294                                 continue;
1295
1296                         /* Coding opportunity is found! */
1297                         list_del(&nc_packet->list);
1298                         nc_packet_out = nc_packet;
1299                         break;
1300                 }
1301
1302                 spin_unlock_bh(&nc_path->packet_list_lock);
1303                 break;
1304         }
1305         rcu_read_unlock();
1306
1307         return nc_packet_out;
1308 }
1309
1310 /**
1311  * batadv_nc_skb_src_search - Loops through the list of neighoring nodes of the
1312  *  skb's sender (may be equal to the originator).
1313  * @bat_priv: the bat priv with all the soft interface information
1314  * @skb: data skb to forward
1315  * @eth_dst: next hop mac address of skb
1316  * @eth_src: source mac address of skb
1317  * @in_nc_node: pointer to skb next hop's neighbor nc node
1318  *
1319  * Returns an nc packet if a suitable coding packet was found, NULL otherwise.
1320  */
1321 static struct batadv_nc_packet *
1322 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1323                          struct sk_buff *skb,
1324                          u8 *eth_dst,
1325                          u8 *eth_src,
1326                          struct batadv_nc_node *in_nc_node)
1327 {
1328         struct batadv_orig_node *orig_node;
1329         struct batadv_nc_node *out_nc_node;
1330         struct batadv_nc_packet *nc_packet = NULL;
1331
1332         orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1333         if (!orig_node)
1334                 return NULL;
1335
1336         rcu_read_lock();
1337         list_for_each_entry_rcu(out_nc_node,
1338                                 &orig_node->out_coding_list, list) {
1339                 /* Check if the skb is decoded and if recoding is possible */
1340                 if (!batadv_nc_skb_coding_possible(skb,
1341                                                    out_nc_node->addr, eth_src))
1342                         continue;
1343
1344                 /* Search for an opportunity in this nc_path */
1345                 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1346                                                   out_nc_node, skb, eth_dst);
1347                 if (nc_packet)
1348                         break;
1349         }
1350         rcu_read_unlock();
1351
1352         batadv_orig_node_free_ref(orig_node);
1353         return nc_packet;
1354 }
1355
1356 /**
1357  * batadv_nc_skb_store_before_coding - set the ethernet src and dst of the
1358  *  unicast skb before it is stored for use in later decoding
1359  * @bat_priv: the bat priv with all the soft interface information
1360  * @skb: data skb to store
1361  * @eth_dst_new: new destination mac address of skb
1362  */
1363 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1364                                               struct sk_buff *skb,
1365                                               u8 *eth_dst_new)
1366 {
1367         struct ethhdr *ethhdr;
1368
1369         /* Copy skb header to change the mac header */
1370         skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1371         if (!skb)
1372                 return;
1373
1374         /* Set the mac header as if we actually sent the packet uncoded */
1375         ethhdr = eth_hdr(skb);
1376         ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1377         ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1378
1379         /* Set data pointer to MAC header to mimic packets from our tx path */
1380         skb_push(skb, ETH_HLEN);
1381
1382         /* Add the packet to the decoding packet pool */
1383         batadv_nc_skb_store_for_decoding(bat_priv, skb);
1384
1385         /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1386          * our ref
1387          */
1388         kfree_skb(skb);
1389 }
1390
1391 /**
1392  * batadv_nc_skb_dst_search - Loops through list of neighboring nodes to dst.
1393  * @skb: data skb to forward
1394  * @neigh_node: next hop to forward packet to
1395  * @ethhdr: pointer to the ethernet header inside the skb
1396  *
1397  * Loops through list of neighboring nodes the next hop has a good connection to
1398  * (receives OGMs with a sufficient quality). We need to find a neighbor of our
1399  * next hop that potentially sent a packet which our next hop also received
1400  * (overheard) and has stored for later decoding.
1401  *
1402  * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1403  */
1404 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1405                                      struct batadv_neigh_node *neigh_node,
1406                                      struct ethhdr *ethhdr)
1407 {
1408         struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1409         struct batadv_priv *bat_priv = netdev_priv(netdev);
1410         struct batadv_orig_node *orig_node = neigh_node->orig_node;
1411         struct batadv_nc_node *nc_node;
1412         struct batadv_nc_packet *nc_packet = NULL;
1413
1414         rcu_read_lock();
1415         list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1416                 /* Search for coding opportunity with this in_nc_node */
1417                 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1418                                                      neigh_node->addr,
1419                                                      ethhdr->h_source, nc_node);
1420
1421                 /* Opportunity was found, so stop searching */
1422                 if (nc_packet)
1423                         break;
1424         }
1425         rcu_read_unlock();
1426
1427         if (!nc_packet)
1428                 return false;
1429
1430         /* Save packets for later decoding */
1431         batadv_nc_skb_store_before_coding(bat_priv, skb,
1432                                           neigh_node->addr);
1433         batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1434                                           nc_packet->neigh_node->addr);
1435
1436         /* Code and send packets */
1437         if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1438                                    neigh_node))
1439                 return true;
1440
1441         /* out of mem ? Coding failed - we have to free the buffered packet
1442          * to avoid memleaks. The skb passed as argument will be dealt with
1443          * by the calling function.
1444          */
1445         batadv_nc_send_packet(nc_packet);
1446         return false;
1447 }
1448
1449 /**
1450  * batadv_nc_skb_add_to_path - buffer skb for later encoding / decoding
1451  * @skb: skb to add to path
1452  * @nc_path: path to add skb to
1453  * @neigh_node: next hop to forward packet to
1454  * @packet_id: checksum to identify packet
1455  *
1456  * Returns true if the packet was buffered or false in case of an error.
1457  */
1458 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1459                                       struct batadv_nc_path *nc_path,
1460                                       struct batadv_neigh_node *neigh_node,
1461                                       __be32 packet_id)
1462 {
1463         struct batadv_nc_packet *nc_packet;
1464
1465         nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1466         if (!nc_packet)
1467                 return false;
1468
1469         /* Initialize nc_packet */
1470         nc_packet->timestamp = jiffies;
1471         nc_packet->packet_id = packet_id;
1472         nc_packet->skb = skb;
1473         nc_packet->neigh_node = neigh_node;
1474         nc_packet->nc_path = nc_path;
1475
1476         /* Add coding packet to list */
1477         spin_lock_bh(&nc_path->packet_list_lock);
1478         list_add_tail(&nc_packet->list, &nc_path->packet_list);
1479         spin_unlock_bh(&nc_path->packet_list_lock);
1480
1481         return true;
1482 }
1483
1484 /**
1485  * batadv_nc_skb_forward - try to code a packet or add it to the coding packet
1486  *  buffer
1487  * @skb: data skb to forward
1488  * @neigh_node: next hop to forward packet to
1489  *
1490  * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1491  */
1492 bool batadv_nc_skb_forward(struct sk_buff *skb,
1493                            struct batadv_neigh_node *neigh_node)
1494 {
1495         const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1496         struct batadv_priv *bat_priv = netdev_priv(netdev);
1497         struct batadv_unicast_packet *packet;
1498         struct batadv_nc_path *nc_path;
1499         struct ethhdr *ethhdr = eth_hdr(skb);
1500         __be32 packet_id;
1501         u8 *payload;
1502
1503         /* Check if network coding is enabled */
1504         if (!atomic_read(&bat_priv->network_coding))
1505                 goto out;
1506
1507         /* We only handle unicast packets */
1508         payload = skb_network_header(skb);
1509         packet = (struct batadv_unicast_packet *)payload;
1510         if (packet->packet_type != BATADV_UNICAST)
1511                 goto out;
1512
1513         /* Try to find a coding opportunity and send the skb if one is found */
1514         if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1515                 return true;
1516
1517         /* Find or create a nc_path for this src-dst pair */
1518         nc_path = batadv_nc_get_path(bat_priv,
1519                                      bat_priv->nc.coding_hash,
1520                                      ethhdr->h_source,
1521                                      neigh_node->addr);
1522
1523         if (!nc_path)
1524                 goto out;
1525
1526         /* Add skb to nc_path */
1527         packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1528         if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1529                 goto free_nc_path;
1530
1531         /* Packet is consumed */
1532         return true;
1533
1534 free_nc_path:
1535         batadv_nc_path_free_ref(nc_path);
1536 out:
1537         /* Packet is not consumed */
1538         return false;
1539 }
1540
1541 /**
1542  * batadv_nc_skb_store_for_decoding - save a clone of the skb which can be used
1543  *  when decoding coded packets
1544  * @bat_priv: the bat priv with all the soft interface information
1545  * @skb: data skb to store
1546  */
1547 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1548                                       struct sk_buff *skb)
1549 {
1550         struct batadv_unicast_packet *packet;
1551         struct batadv_nc_path *nc_path;
1552         struct ethhdr *ethhdr = eth_hdr(skb);
1553         __be32 packet_id;
1554         u8 *payload;
1555
1556         /* Check if network coding is enabled */
1557         if (!atomic_read(&bat_priv->network_coding))
1558                 goto out;
1559
1560         /* Check for supported packet type */
1561         payload = skb_network_header(skb);
1562         packet = (struct batadv_unicast_packet *)payload;
1563         if (packet->packet_type != BATADV_UNICAST)
1564                 goto out;
1565
1566         /* Find existing nc_path or create a new */
1567         nc_path = batadv_nc_get_path(bat_priv,
1568                                      bat_priv->nc.decoding_hash,
1569                                      ethhdr->h_source,
1570                                      ethhdr->h_dest);
1571
1572         if (!nc_path)
1573                 goto out;
1574
1575         /* Clone skb and adjust skb->data to point at batman header */
1576         skb = skb_clone(skb, GFP_ATOMIC);
1577         if (unlikely(!skb))
1578                 goto free_nc_path;
1579
1580         if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1581                 goto free_skb;
1582
1583         if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1584                 goto free_skb;
1585
1586         /* Add skb to nc_path */
1587         packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1588         if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1589                 goto free_skb;
1590
1591         batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1592         return;
1593
1594 free_skb:
1595         kfree_skb(skb);
1596 free_nc_path:
1597         batadv_nc_path_free_ref(nc_path);
1598 out:
1599         return;
1600 }
1601
1602 /**
1603  * batadv_nc_skb_store_sniffed_unicast - check if a received unicast packet
1604  *  should be saved in the decoding buffer and, if so, store it there
1605  * @bat_priv: the bat priv with all the soft interface information
1606  * @skb: unicast skb to store
1607  */
1608 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1609                                          struct sk_buff *skb)
1610 {
1611         struct ethhdr *ethhdr = eth_hdr(skb);
1612
1613         if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1614                 return;
1615
1616         /* Set data pointer to MAC header to mimic packets from our tx path */
1617         skb_push(skb, ETH_HLEN);
1618
1619         batadv_nc_skb_store_for_decoding(bat_priv, skb);
1620 }
1621
1622 /**
1623  * batadv_nc_skb_decode_packet - decode given skb using the decode data stored
1624  *  in nc_packet
1625  * @bat_priv: the bat priv with all the soft interface information
1626  * @skb: unicast skb to decode
1627  * @nc_packet: decode data needed to decode the skb
1628  *
1629  * Returns pointer to decoded unicast packet if the packet was decoded or NULL
1630  * in case of an error.
1631  */
1632 static struct batadv_unicast_packet *
1633 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1634                             struct batadv_nc_packet *nc_packet)
1635 {
1636         const int h_size = sizeof(struct batadv_unicast_packet);
1637         const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1638         struct batadv_unicast_packet *unicast_packet;
1639         struct batadv_coded_packet coded_packet_tmp;
1640         struct ethhdr *ethhdr, ethhdr_tmp;
1641         u8 *orig_dest, ttl, ttvn;
1642         unsigned int coding_len;
1643         int err;
1644
1645         /* Save headers temporarily */
1646         memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1647         memcpy(&ethhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1648
1649         if (skb_cow(skb, 0) < 0)
1650                 return NULL;
1651
1652         if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1653                 return NULL;
1654
1655         /* Data points to batman header, so set mac header 14 bytes before
1656          * and network to data
1657          */
1658         skb_set_mac_header(skb, -ETH_HLEN);
1659         skb_reset_network_header(skb);
1660
1661         /* Reconstruct original mac header */
1662         ethhdr = eth_hdr(skb);
1663         *ethhdr = ethhdr_tmp;
1664
1665         /* Select the correct unicast header information based on the location
1666          * of our mac address in the coded_packet header
1667          */
1668         if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1669                 /* If we are the second destination the packet was overheard,
1670                  * so the Ethernet address must be copied to h_dest and
1671                  * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1672                  */
1673                 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1674                 skb->pkt_type = PACKET_HOST;
1675
1676                 orig_dest = coded_packet_tmp.second_orig_dest;
1677                 ttl = coded_packet_tmp.second_ttl;
1678                 ttvn = coded_packet_tmp.second_ttvn;
1679         } else {
1680                 orig_dest = coded_packet_tmp.first_orig_dest;
1681                 ttl = coded_packet_tmp.ttl;
1682                 ttvn = coded_packet_tmp.first_ttvn;
1683         }
1684
1685         coding_len = ntohs(coded_packet_tmp.coded_len);
1686
1687         if (coding_len > skb->len)
1688                 return NULL;
1689
1690         /* Here the magic is reversed:
1691          *   extract the missing packet from the received coded packet
1692          */
1693         batadv_nc_memxor(skb->data + h_size,
1694                          nc_packet->skb->data + h_size,
1695                          coding_len);
1696
1697         /* Resize decoded skb if decoded with larger packet */
1698         if (nc_packet->skb->len > coding_len + h_size) {
1699                 err = pskb_trim_rcsum(skb, coding_len + h_size);
1700                 if (err)
1701                         return NULL;
1702         }
1703
1704         /* Create decoded unicast packet */
1705         unicast_packet = (struct batadv_unicast_packet *)skb->data;
1706         unicast_packet->packet_type = BATADV_UNICAST;
1707         unicast_packet->version = BATADV_COMPAT_VERSION;
1708         unicast_packet->ttl = ttl;
1709         ether_addr_copy(unicast_packet->dest, orig_dest);
1710         unicast_packet->ttvn = ttvn;
1711
1712         batadv_nc_packet_free(nc_packet);
1713         return unicast_packet;
1714 }
1715
1716 /**
1717  * batadv_nc_find_decoding_packet - search through buffered decoding data to
1718  *  find the data needed to decode the coded packet
1719  * @bat_priv: the bat priv with all the soft interface information
1720  * @ethhdr: pointer to the ethernet header inside the coded packet
1721  * @coded: coded packet we try to find decode data for
1722  *
1723  * Returns pointer to nc packet if the needed data was found or NULL otherwise.
1724  */
1725 static struct batadv_nc_packet *
1726 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1727                                struct ethhdr *ethhdr,
1728                                struct batadv_coded_packet *coded)
1729 {
1730         struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1731         struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1732         struct batadv_nc_path *nc_path, nc_path_key;
1733         u8 *dest, *source;
1734         __be32 packet_id;
1735         int index;
1736
1737         if (!hash)
1738                 return NULL;
1739
1740         /* Select the correct packet id based on the location of our mac-addr */
1741         dest = ethhdr->h_source;
1742         if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1743                 source = coded->second_source;
1744                 packet_id = coded->second_crc;
1745         } else {
1746                 source = coded->first_source;
1747                 packet_id = coded->first_crc;
1748         }
1749
1750         batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1751         index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1752
1753         /* Search for matching coding path */
1754         rcu_read_lock();
1755         hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1756                 /* Find matching nc_packet */
1757                 spin_lock_bh(&nc_path->packet_list_lock);
1758                 list_for_each_entry(tmp_nc_packet,
1759                                     &nc_path->packet_list, list) {
1760                         if (packet_id == tmp_nc_packet->packet_id) {
1761                                 list_del(&tmp_nc_packet->list);
1762
1763                                 nc_packet = tmp_nc_packet;
1764                                 break;
1765                         }
1766                 }
1767                 spin_unlock_bh(&nc_path->packet_list_lock);
1768
1769                 if (nc_packet)
1770                         break;
1771         }
1772         rcu_read_unlock();
1773
1774         if (!nc_packet)
1775                 batadv_dbg(BATADV_DBG_NC, bat_priv,
1776                            "No decoding packet found for %u\n", packet_id);
1777
1778         return nc_packet;
1779 }
1780
1781 /**
1782  * batadv_nc_recv_coded_packet - try to decode coded packet and enqueue the
1783  *  resulting unicast packet
1784  * @skb: incoming coded packet
1785  * @recv_if: pointer to interface this packet was received on
1786  */
1787 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1788                                        struct batadv_hard_iface *recv_if)
1789 {
1790         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1791         struct batadv_unicast_packet *unicast_packet;
1792         struct batadv_coded_packet *coded_packet;
1793         struct batadv_nc_packet *nc_packet;
1794         struct ethhdr *ethhdr;
1795         int hdr_size = sizeof(*coded_packet);
1796
1797         /* Check if network coding is enabled */
1798         if (!atomic_read(&bat_priv->network_coding))
1799                 return NET_RX_DROP;
1800
1801         /* Make sure we can access (and remove) header */
1802         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1803                 return NET_RX_DROP;
1804
1805         coded_packet = (struct batadv_coded_packet *)skb->data;
1806         ethhdr = eth_hdr(skb);
1807
1808         /* Verify frame is destined for us */
1809         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1810             !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1811                 return NET_RX_DROP;
1812
1813         /* Update stat counter */
1814         if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1815                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1816
1817         nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1818                                                    coded_packet);
1819         if (!nc_packet) {
1820                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1821                 return NET_RX_DROP;
1822         }
1823
1824         /* Make skb's linear, because decoding accesses the entire buffer */
1825         if (skb_linearize(skb) < 0)
1826                 goto free_nc_packet;
1827
1828         if (skb_linearize(nc_packet->skb) < 0)
1829                 goto free_nc_packet;
1830
1831         /* Decode the packet */
1832         unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1833         if (!unicast_packet) {
1834                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1835                 goto free_nc_packet;
1836         }
1837
1838         /* Mark packet as decoded to do correct recoding when forwarding */
1839         BATADV_SKB_CB(skb)->decoded = true;
1840         batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1841         batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1842                            skb->len + ETH_HLEN);
1843         return batadv_recv_unicast_packet(skb, recv_if);
1844
1845 free_nc_packet:
1846         batadv_nc_packet_free(nc_packet);
1847         return NET_RX_DROP;
1848 }
1849
1850 /**
1851  * batadv_nc_mesh_free - clean up network coding memory
1852  * @bat_priv: the bat priv with all the soft interface information
1853  */
1854 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1855 {
1856         batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1857         batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1858         cancel_delayed_work_sync(&bat_priv->nc.work);
1859
1860         batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1861         batadv_hash_destroy(bat_priv->nc.coding_hash);
1862         batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1863         batadv_hash_destroy(bat_priv->nc.decoding_hash);
1864 }
1865
1866 /**
1867  * batadv_nc_nodes_seq_print_text - print the nc node information
1868  * @seq: seq file to print on
1869  * @offset: not used
1870  */
1871 int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
1872 {
1873         struct net_device *net_dev = (struct net_device *)seq->private;
1874         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1875         struct batadv_hashtable *hash = bat_priv->orig_hash;
1876         struct batadv_hard_iface *primary_if;
1877         struct hlist_head *head;
1878         struct batadv_orig_node *orig_node;
1879         struct batadv_nc_node *nc_node;
1880         int i;
1881
1882         primary_if = batadv_seq_print_text_primary_if_get(seq);
1883         if (!primary_if)
1884                 goto out;
1885
1886         /* Traverse list of originators */
1887         for (i = 0; i < hash->size; i++) {
1888                 head = &hash->table[i];
1889
1890                 /* For each orig_node in this bin */
1891                 rcu_read_lock();
1892                 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1893                         /* no need to print the orig node if it does not have
1894                          * network coding neighbors
1895                          */
1896                         if (list_empty(&orig_node->in_coding_list) &&
1897                             list_empty(&orig_node->out_coding_list))
1898                                 continue;
1899
1900                         seq_printf(seq, "Node:      %pM\n", orig_node->orig);
1901
1902                         seq_puts(seq, " Ingoing:  ");
1903                         /* For each in_nc_node to this orig_node */
1904                         list_for_each_entry_rcu(nc_node,
1905                                                 &orig_node->in_coding_list,
1906                                                 list)
1907                                 seq_printf(seq, "%pM ",
1908                                            nc_node->addr);
1909                         seq_puts(seq, "\n");
1910
1911                         seq_puts(seq, " Outgoing: ");
1912                         /* For out_nc_node to this orig_node */
1913                         list_for_each_entry_rcu(nc_node,
1914                                                 &orig_node->out_coding_list,
1915                                                 list)
1916                                 seq_printf(seq, "%pM ",
1917                                            nc_node->addr);
1918                         seq_puts(seq, "\n\n");
1919                 }
1920                 rcu_read_unlock();
1921         }
1922
1923 out:
1924         if (primary_if)
1925                 batadv_hardif_free_ref(primary_if);
1926         return 0;
1927 }
1928
1929 /**
1930  * batadv_nc_init_debugfs - create nc folder and related files in debugfs
1931  * @bat_priv: the bat priv with all the soft interface information
1932  */
1933 int batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
1934 {
1935         struct dentry *nc_dir, *file;
1936
1937         nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
1938         if (!nc_dir)
1939                 goto out;
1940
1941         file = debugfs_create_u8("min_tq", S_IRUGO | S_IWUSR, nc_dir,
1942                                  &bat_priv->nc.min_tq);
1943         if (!file)
1944                 goto out;
1945
1946         file = debugfs_create_u32("max_fwd_delay", S_IRUGO | S_IWUSR, nc_dir,
1947                                   &bat_priv->nc.max_fwd_delay);
1948         if (!file)
1949                 goto out;
1950
1951         file = debugfs_create_u32("max_buffer_time", S_IRUGO | S_IWUSR, nc_dir,
1952                                   &bat_priv->nc.max_buffer_time);
1953         if (!file)
1954                 goto out;
1955
1956         return 0;
1957
1958 out:
1959         return -ENOMEM;
1960 }