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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         kfree_skb(nc_packet->skb);
245         batadv_nc_path_free_ref(nc_packet->nc_path);
246         kfree(nc_packet);
247 }
248
249 /**
250  * batadv_nc_to_purge_nc_node - checks whether an nc node has to be purged
251  * @bat_priv: the bat priv with all the soft interface information
252  * @nc_node: the nc node to check
253  *
254  * Returns true if the entry has to be purged now, false otherwise
255  */
256 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
257                                        struct batadv_nc_node *nc_node)
258 {
259         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
260                 return true;
261
262         return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
263 }
264
265 /**
266  * batadv_nc_to_purge_nc_path_coding - checks whether an nc path has timed out
267  * @bat_priv: the bat priv with all the soft interface information
268  * @nc_path: the nc path to check
269  *
270  * Returns true if the entry has to be purged now, false otherwise
271  */
272 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
273                                               struct batadv_nc_path *nc_path)
274 {
275         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
276                 return true;
277
278         /* purge the path when no packets has been added for 10 times the
279          * max_fwd_delay time
280          */
281         return batadv_has_timed_out(nc_path->last_valid,
282                                     bat_priv->nc.max_fwd_delay * 10);
283 }
284
285 /**
286  * batadv_nc_to_purge_nc_path_decoding - checks whether an nc path has timed out
287  * @bat_priv: the bat priv with all the soft interface information
288  * @nc_path: the nc path to check
289  *
290  * Returns true if the entry has to be purged now, false otherwise
291  */
292 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
293                                                 struct batadv_nc_path *nc_path)
294 {
295         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
296                 return true;
297
298         /* purge the path when no packets has been added for 10 times the
299          * max_buffer time
300          */
301         return batadv_has_timed_out(nc_path->last_valid,
302                                     bat_priv->nc.max_buffer_time * 10);
303 }
304
305 /**
306  * batadv_nc_purge_orig_nc_nodes - go through list of nc nodes and purge stale
307  *  entries
308  * @bat_priv: the bat priv with all the soft interface information
309  * @list: list of nc nodes
310  * @lock: nc node list lock
311  * @to_purge: function in charge to decide whether an entry has to be purged or
312  *            not. This function takes the nc node as argument and has to return
313  *            a boolean value: true if the entry has to be deleted, false
314  *            otherwise
315  */
316 static void
317 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
318                               struct list_head *list,
319                               spinlock_t *lock,
320                               bool (*to_purge)(struct batadv_priv *,
321                                                struct batadv_nc_node *))
322 {
323         struct batadv_nc_node *nc_node, *nc_node_tmp;
324
325         /* For each nc_node in list */
326         spin_lock_bh(lock);
327         list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
328                 /* if an helper function has been passed as parameter,
329                  * ask it if the entry has to be purged or not
330                  */
331                 if (to_purge && !to_purge(bat_priv, nc_node))
332                         continue;
333
334                 batadv_dbg(BATADV_DBG_NC, bat_priv,
335                            "Removing nc_node %pM -> %pM\n",
336                            nc_node->addr, nc_node->orig_node->orig);
337                 list_del_rcu(&nc_node->list);
338                 batadv_nc_node_free_ref(nc_node);
339         }
340         spin_unlock_bh(lock);
341 }
342
343 /**
344  * batadv_nc_purge_orig - purges all nc node data attached of the given
345  *  originator
346  * @bat_priv: the bat priv with all the soft interface information
347  * @orig_node: orig_node with the nc node entries to be purged
348  * @to_purge: function in charge to decide whether an entry has to be purged or
349  *            not. This function takes the nc node as argument and has to return
350  *            a boolean value: true is the entry has to be deleted, false
351  *            otherwise
352  */
353 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
354                           struct batadv_orig_node *orig_node,
355                           bool (*to_purge)(struct batadv_priv *,
356                                            struct batadv_nc_node *))
357 {
358         /* Check ingoing nc_node's of this orig_node */
359         batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
360                                       &orig_node->in_coding_list_lock,
361                                       to_purge);
362
363         /* Check outgoing nc_node's of this orig_node */
364         batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
365                                       &orig_node->out_coding_list_lock,
366                                       to_purge);
367 }
368
369 /**
370  * batadv_nc_purge_orig_hash - traverse entire originator hash to check if they
371  *  have timed out nc nodes
372  * @bat_priv: the bat priv with all the soft interface information
373  */
374 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
375 {
376         struct batadv_hashtable *hash = bat_priv->orig_hash;
377         struct hlist_head *head;
378         struct batadv_orig_node *orig_node;
379         u32 i;
380
381         if (!hash)
382                 return;
383
384         /* For each orig_node */
385         for (i = 0; i < hash->size; i++) {
386                 head = &hash->table[i];
387
388                 rcu_read_lock();
389                 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
390                         batadv_nc_purge_orig(bat_priv, orig_node,
391                                              batadv_nc_to_purge_nc_node);
392                 rcu_read_unlock();
393         }
394 }
395
396 /**
397  * batadv_nc_purge_paths - traverse all nc paths part of the hash and remove
398  *  unused ones
399  * @bat_priv: the bat priv with all the soft interface information
400  * @hash: hash table containing the nc paths to check
401  * @to_purge: function in charge to decide whether an entry has to be purged or
402  *            not. This function takes the nc node as argument and has to return
403  *            a boolean value: true is the entry has to be deleted, false
404  *            otherwise
405  */
406 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
407                                   struct batadv_hashtable *hash,
408                                   bool (*to_purge)(struct batadv_priv *,
409                                                    struct batadv_nc_path *))
410 {
411         struct hlist_head *head;
412         struct hlist_node *node_tmp;
413         struct batadv_nc_path *nc_path;
414         spinlock_t *lock; /* Protects lists in hash */
415         u32 i;
416
417         for (i = 0; i < hash->size; i++) {
418                 head = &hash->table[i];
419                 lock = &hash->list_locks[i];
420
421                 /* For each nc_path in this bin */
422                 spin_lock_bh(lock);
423                 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
424                         /* if an helper function has been passed as parameter,
425                          * ask it if the entry has to be purged or not
426                          */
427                         if (to_purge && !to_purge(bat_priv, nc_path))
428                                 continue;
429
430                         /* purging an non-empty nc_path should never happen, but
431                          * is observed under high CPU load. Delay the purging
432                          * until next iteration to allow the packet_list to be
433                          * emptied first.
434                          */
435                         if (!unlikely(list_empty(&nc_path->packet_list))) {
436                                 net_ratelimited_function(printk,
437                                                          KERN_WARNING
438                                                          "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
439                                                          nc_path->prev_hop,
440                                                          nc_path->next_hop);
441                                 continue;
442                         }
443
444                         /* nc_path is unused, so remove it */
445                         batadv_dbg(BATADV_DBG_NC, bat_priv,
446                                    "Remove nc_path %pM -> %pM\n",
447                                    nc_path->prev_hop, nc_path->next_hop);
448                         hlist_del_rcu(&nc_path->hash_entry);
449                         batadv_nc_path_free_ref(nc_path);
450                 }
451                 spin_unlock_bh(lock);
452         }
453 }
454
455 /**
456  * batadv_nc_hash_key_gen - computes the nc_path hash key
457  * @key: buffer to hold the final hash key
458  * @src: source ethernet mac address going into the hash key
459  * @dst: destination ethernet mac address going into the hash key
460  */
461 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
462                                    const char *dst)
463 {
464         memcpy(key->prev_hop, src, sizeof(key->prev_hop));
465         memcpy(key->next_hop, dst, sizeof(key->next_hop));
466 }
467
468 /**
469  * batadv_nc_hash_choose - compute the hash value for an nc path
470  * @data: data to hash
471  * @size: size of the hash table
472  *
473  * Returns the selected index in the hash table for the given data.
474  */
475 static u32 batadv_nc_hash_choose(const void *data, u32 size)
476 {
477         const struct batadv_nc_path *nc_path = data;
478         u32 hash = 0;
479
480         hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
481         hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
482
483         return hash % size;
484 }
485
486 /**
487  * batadv_nc_hash_compare - comparing function used in the network coding hash
488  *  tables
489  * @node: node in the local table
490  * @data2: second object to compare the node to
491  *
492  * Returns 1 if the two entry are the same, 0 otherwise
493  */
494 static int batadv_nc_hash_compare(const struct hlist_node *node,
495                                   const void *data2)
496 {
497         const struct batadv_nc_path *nc_path1, *nc_path2;
498
499         nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
500         nc_path2 = data2;
501
502         /* Return 1 if the two keys are identical */
503         if (memcmp(nc_path1->prev_hop, nc_path2->prev_hop,
504                    sizeof(nc_path1->prev_hop)) != 0)
505                 return 0;
506
507         if (memcmp(nc_path1->next_hop, nc_path2->next_hop,
508                    sizeof(nc_path1->next_hop)) != 0)
509                 return 0;
510
511         return 1;
512 }
513
514 /**
515  * batadv_nc_hash_find - search for an existing nc path and return it
516  * @hash: hash table containing the nc path
517  * @data: search key
518  *
519  * Returns the nc_path if found, NULL otherwise.
520  */
521 static struct batadv_nc_path *
522 batadv_nc_hash_find(struct batadv_hashtable *hash,
523                     void *data)
524 {
525         struct hlist_head *head;
526         struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
527         int index;
528
529         if (!hash)
530                 return NULL;
531
532         index = batadv_nc_hash_choose(data, hash->size);
533         head = &hash->table[index];
534
535         rcu_read_lock();
536         hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
537                 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
538                         continue;
539
540                 if (!atomic_inc_not_zero(&nc_path->refcount))
541                         continue;
542
543                 nc_path_tmp = nc_path;
544                 break;
545         }
546         rcu_read_unlock();
547
548         return nc_path_tmp;
549 }
550
551 /**
552  * batadv_nc_send_packet - send non-coded packet and free nc_packet struct
553  * @nc_packet: the nc packet to send
554  */
555 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
556 {
557         batadv_send_skb_packet(nc_packet->skb,
558                                nc_packet->neigh_node->if_incoming,
559                                nc_packet->nc_path->next_hop);
560         nc_packet->skb = NULL;
561         batadv_nc_packet_free(nc_packet);
562 }
563
564 /**
565  * batadv_nc_sniffed_purge - Checks timestamp of given sniffed nc_packet.
566  * @bat_priv: the bat priv with all the soft interface information
567  * @nc_path: the nc path the packet belongs to
568  * @nc_packet: the nc packet to be checked
569  *
570  * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
571  * timeout. If so, the packet is no longer kept and the entry deleted from the
572  * queue. Has to be called with the appropriate locks.
573  *
574  * Returns false as soon as the entry in the fifo queue has not been timed out
575  * yet and true otherwise.
576  */
577 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
578                                     struct batadv_nc_path *nc_path,
579                                     struct batadv_nc_packet *nc_packet)
580 {
581         unsigned long timeout = bat_priv->nc.max_buffer_time;
582         bool res = false;
583
584         lockdep_assert_held(&nc_path->packet_list_lock);
585
586         /* Packets are added to tail, so the remaining packets did not time
587          * out and we can stop processing the current queue
588          */
589         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
590             !batadv_has_timed_out(nc_packet->timestamp, timeout))
591                 goto out;
592
593         /* purge nc packet */
594         list_del(&nc_packet->list);
595         batadv_nc_packet_free(nc_packet);
596
597         res = true;
598
599 out:
600         return res;
601 }
602
603 /**
604  * batadv_nc_fwd_flush - Checks the timestamp of the given nc packet.
605  * @bat_priv: the bat priv with all the soft interface information
606  * @nc_path: the nc path the packet belongs to
607  * @nc_packet: the nc packet to be checked
608  *
609  * Checks whether the given nc packet has hit its forward timeout. If so, the
610  * packet is no longer delayed, immediately sent and the entry deleted from the
611  * queue. Has to be called with the appropriate locks.
612  *
613  * Returns false as soon as the entry in the fifo queue has not been timed out
614  * yet and true otherwise.
615  */
616 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
617                                 struct batadv_nc_path *nc_path,
618                                 struct batadv_nc_packet *nc_packet)
619 {
620         unsigned long timeout = bat_priv->nc.max_fwd_delay;
621
622         lockdep_assert_held(&nc_path->packet_list_lock);
623
624         /* Packets are added to tail, so the remaining packets did not time
625          * out and we can stop processing the current queue
626          */
627         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
628             !batadv_has_timed_out(nc_packet->timestamp, timeout))
629                 return false;
630
631         /* Send packet */
632         batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
633         batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
634                            nc_packet->skb->len + ETH_HLEN);
635         list_del(&nc_packet->list);
636         batadv_nc_send_packet(nc_packet);
637
638         return true;
639 }
640
641 /**
642  * batadv_nc_process_nc_paths - traverse given nc packet pool and free timed out
643  *  nc packets
644  * @bat_priv: the bat priv with all the soft interface information
645  * @hash: to be processed hash table
646  * @process_fn: Function called to process given nc packet. Should return true
647  *              to encourage this function to proceed with the next packet.
648  *              Otherwise the rest of the current queue is skipped.
649  */
650 static void
651 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
652                            struct batadv_hashtable *hash,
653                            bool (*process_fn)(struct batadv_priv *,
654                                               struct batadv_nc_path *,
655                                               struct batadv_nc_packet *))
656 {
657         struct hlist_head *head;
658         struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
659         struct batadv_nc_path *nc_path;
660         bool ret;
661         int i;
662
663         if (!hash)
664                 return;
665
666         /* Loop hash table bins */
667         for (i = 0; i < hash->size; i++) {
668                 head = &hash->table[i];
669
670                 /* Loop coding paths */
671                 rcu_read_lock();
672                 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
673                         /* Loop packets */
674                         spin_lock_bh(&nc_path->packet_list_lock);
675                         list_for_each_entry_safe(nc_packet, nc_packet_tmp,
676                                                  &nc_path->packet_list, list) {
677                                 ret = process_fn(bat_priv, nc_path, nc_packet);
678                                 if (!ret)
679                                         break;
680                         }
681                         spin_unlock_bh(&nc_path->packet_list_lock);
682                 }
683                 rcu_read_unlock();
684         }
685 }
686
687 /**
688  * batadv_nc_worker - periodic task for house keeping related to network coding
689  * @work: kernel work struct
690  */
691 static void batadv_nc_worker(struct work_struct *work)
692 {
693         struct delayed_work *delayed_work;
694         struct batadv_priv_nc *priv_nc;
695         struct batadv_priv *bat_priv;
696         unsigned long timeout;
697
698         delayed_work = container_of(work, struct delayed_work, work);
699         priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
700         bat_priv = container_of(priv_nc, struct batadv_priv, nc);
701
702         batadv_nc_purge_orig_hash(bat_priv);
703         batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
704                               batadv_nc_to_purge_nc_path_coding);
705         batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
706                               batadv_nc_to_purge_nc_path_decoding);
707
708         timeout = bat_priv->nc.max_fwd_delay;
709
710         if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
711                 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
712                                            batadv_nc_fwd_flush);
713                 bat_priv->nc.timestamp_fwd_flush = jiffies;
714         }
715
716         if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
717                                  bat_priv->nc.max_buffer_time)) {
718                 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
719                                            batadv_nc_sniffed_purge);
720                 bat_priv->nc.timestamp_sniffed_purge = jiffies;
721         }
722
723         /* Schedule a new check */
724         batadv_nc_start_timer(bat_priv);
725 }
726
727 /**
728  * batadv_can_nc_with_orig - checks whether the given orig node is suitable for
729  *  coding or not
730  * @bat_priv: the bat priv with all the soft interface information
731  * @orig_node: neighboring orig node which may be used as nc candidate
732  * @ogm_packet: incoming ogm packet also used for the checks
733  *
734  * Returns true if:
735  *  1) The OGM must have the most recent sequence number.
736  *  2) The TTL must be decremented by one and only one.
737  *  3) The OGM must be received from the first hop from orig_node.
738  *  4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
739  */
740 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
741                                     struct batadv_orig_node *orig_node,
742                                     struct batadv_ogm_packet *ogm_packet)
743 {
744         struct batadv_orig_ifinfo *orig_ifinfo;
745         u32 last_real_seqno;
746         u8 last_ttl;
747
748         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
749         if (!orig_ifinfo)
750                 return false;
751
752         last_ttl = orig_ifinfo->last_ttl;
753         last_real_seqno = orig_ifinfo->last_real_seqno;
754         batadv_orig_ifinfo_free_ref(orig_ifinfo);
755
756         if (last_real_seqno != ntohl(ogm_packet->seqno))
757                 return false;
758         if (last_ttl != ogm_packet->ttl + 1)
759                 return false;
760         if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
761                 return false;
762         if (ogm_packet->tq < bat_priv->nc.min_tq)
763                 return false;
764
765         return true;
766 }
767
768 /**
769  * batadv_nc_find_nc_node - search for an existing nc node and return it
770  * @orig_node: orig node originating the ogm packet
771  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
772  *  (can be equal to orig_node)
773  * @in_coding: traverse incoming or outgoing network coding list
774  *
775  * Returns the nc_node if found, NULL otherwise.
776  */
777 static struct batadv_nc_node
778 *batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
779                         struct batadv_orig_node *orig_neigh_node,
780                         bool in_coding)
781 {
782         struct batadv_nc_node *nc_node, *nc_node_out = NULL;
783         struct list_head *list;
784
785         if (in_coding)
786                 list = &orig_neigh_node->in_coding_list;
787         else
788                 list = &orig_neigh_node->out_coding_list;
789
790         /* Traverse list of nc_nodes to orig_node */
791         rcu_read_lock();
792         list_for_each_entry_rcu(nc_node, list, list) {
793                 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
794                         continue;
795
796                 if (!atomic_inc_not_zero(&nc_node->refcount))
797                         continue;
798
799                 /* Found a match */
800                 nc_node_out = nc_node;
801                 break;
802         }
803         rcu_read_unlock();
804
805         return nc_node_out;
806 }
807
808 /**
809  * batadv_nc_get_nc_node - retrieves an nc node or creates the entry if it was
810  *  not found
811  * @bat_priv: the bat priv with all the soft interface information
812  * @orig_node: orig node originating the ogm packet
813  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
814  *  (can be equal to orig_node)
815  * @in_coding: traverse incoming or outgoing network coding list
816  *
817  * Returns the nc_node if found or created, NULL in case of an error.
818  */
819 static struct batadv_nc_node
820 *batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
821                        struct batadv_orig_node *orig_node,
822                        struct batadv_orig_node *orig_neigh_node,
823                        bool in_coding)
824 {
825         struct batadv_nc_node *nc_node;
826         spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
827         struct list_head *list;
828
829         /* Check if nc_node is already added */
830         nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
831
832         /* Node found */
833         if (nc_node)
834                 return nc_node;
835
836         nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
837         if (!nc_node)
838                 return NULL;
839
840         if (!atomic_inc_not_zero(&orig_neigh_node->refcount))
841                 goto free;
842
843         /* Initialize nc_node */
844         INIT_LIST_HEAD(&nc_node->list);
845         ether_addr_copy(nc_node->addr, orig_node->orig);
846         nc_node->orig_node = orig_neigh_node;
847         atomic_set(&nc_node->refcount, 2);
848
849         /* Select ingoing or outgoing coding node */
850         if (in_coding) {
851                 lock = &orig_neigh_node->in_coding_list_lock;
852                 list = &orig_neigh_node->in_coding_list;
853         } else {
854                 lock = &orig_neigh_node->out_coding_list_lock;
855                 list = &orig_neigh_node->out_coding_list;
856         }
857
858         batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
859                    nc_node->addr, nc_node->orig_node->orig);
860
861         /* Add nc_node to orig_node */
862         spin_lock_bh(lock);
863         list_add_tail_rcu(&nc_node->list, list);
864         spin_unlock_bh(lock);
865
866         return nc_node;
867
868 free:
869         kfree(nc_node);
870         return NULL;
871 }
872
873 /**
874  * batadv_nc_update_nc_node - updates stored incoming and outgoing nc node
875  *  structs (best called on incoming OGMs)
876  * @bat_priv: the bat priv with all the soft interface information
877  * @orig_node: orig node originating the ogm packet
878  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
879  *  (can be equal to orig_node)
880  * @ogm_packet: incoming ogm packet
881  * @is_single_hop_neigh: orig_node is a single hop neighbor
882  */
883 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
884                               struct batadv_orig_node *orig_node,
885                               struct batadv_orig_node *orig_neigh_node,
886                               struct batadv_ogm_packet *ogm_packet,
887                               int is_single_hop_neigh)
888 {
889         struct batadv_nc_node *in_nc_node = NULL;
890         struct batadv_nc_node *out_nc_node = NULL;
891
892         /* Check if network coding is enabled */
893         if (!atomic_read(&bat_priv->network_coding))
894                 goto out;
895
896         /* check if orig node is network coding enabled */
897         if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
898                 goto out;
899
900         /* accept ogms from 'good' neighbors and single hop neighbors */
901         if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
902             !is_single_hop_neigh)
903                 goto out;
904
905         /* Add orig_node as in_nc_node on hop */
906         in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
907                                            orig_neigh_node, true);
908         if (!in_nc_node)
909                 goto out;
910
911         in_nc_node->last_seen = jiffies;
912
913         /* Add hop as out_nc_node on orig_node */
914         out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
915                                             orig_node, false);
916         if (!out_nc_node)
917                 goto out;
918
919         out_nc_node->last_seen = jiffies;
920
921 out:
922         if (in_nc_node)
923                 batadv_nc_node_free_ref(in_nc_node);
924         if (out_nc_node)
925                 batadv_nc_node_free_ref(out_nc_node);
926 }
927
928 /**
929  * batadv_nc_get_path - get existing nc_path or allocate a new one
930  * @bat_priv: the bat priv with all the soft interface information
931  * @hash: hash table containing the nc path
932  * @src: ethernet source address - first half of the nc path search key
933  * @dst: ethernet destination address - second half of the nc path search key
934  *
935  * Returns pointer to nc_path if the path was found or created, returns NULL
936  * on error.
937  */
938 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
939                                                  struct batadv_hashtable *hash,
940                                                  u8 *src,
941                                                  u8 *dst)
942 {
943         int hash_added;
944         struct batadv_nc_path *nc_path, nc_path_key;
945
946         batadv_nc_hash_key_gen(&nc_path_key, src, dst);
947
948         /* Search for existing nc_path */
949         nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
950
951         if (nc_path) {
952                 /* Set timestamp to delay removal of nc_path */
953                 nc_path->last_valid = jiffies;
954                 return nc_path;
955         }
956
957         /* No existing nc_path was found; create a new */
958         nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
959
960         if (!nc_path)
961                 return NULL;
962
963         /* Initialize nc_path */
964         INIT_LIST_HEAD(&nc_path->packet_list);
965         spin_lock_init(&nc_path->packet_list_lock);
966         atomic_set(&nc_path->refcount, 2);
967         nc_path->last_valid = jiffies;
968         ether_addr_copy(nc_path->next_hop, dst);
969         ether_addr_copy(nc_path->prev_hop, src);
970
971         batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
972                    nc_path->prev_hop,
973                    nc_path->next_hop);
974
975         /* Add nc_path to hash table */
976         hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
977                                      batadv_nc_hash_choose, &nc_path_key,
978                                      &nc_path->hash_entry);
979
980         if (hash_added < 0) {
981                 kfree(nc_path);
982                 return NULL;
983         }
984
985         return nc_path;
986 }
987
988 /**
989  * batadv_nc_random_weight_tq - scale the receivers TQ-value to avoid unfair
990  *  selection of a receiver with slightly lower TQ than the other
991  * @tq: to be weighted tq value
992  */
993 static u8 batadv_nc_random_weight_tq(u8 tq)
994 {
995         u8 rand_val, rand_tq;
996
997         get_random_bytes(&rand_val, sizeof(rand_val));
998
999         /* randomize the estimated packet loss (max TQ - estimated TQ) */
1000         rand_tq = rand_val * (BATADV_TQ_MAX_VALUE - tq);
1001
1002         /* normalize the randomized packet loss */
1003         rand_tq /= BATADV_TQ_MAX_VALUE;
1004
1005         /* convert to (randomized) estimated tq again */
1006         return BATADV_TQ_MAX_VALUE - rand_tq;
1007 }
1008
1009 /**
1010  * batadv_nc_memxor - XOR destination with source
1011  * @dst: byte array to XOR into
1012  * @src: byte array to XOR from
1013  * @len: length of destination array
1014  */
1015 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
1016 {
1017         unsigned int i;
1018
1019         for (i = 0; i < len; ++i)
1020                 dst[i] ^= src[i];
1021 }
1022
1023 /**
1024  * batadv_nc_code_packets - code a received unicast_packet with an nc packet
1025  *  into a coded_packet and send it
1026  * @bat_priv: the bat priv with all the soft interface information
1027  * @skb: data skb to forward
1028  * @ethhdr: pointer to the ethernet header inside the skb
1029  * @nc_packet: structure containing the packet to the skb can be coded with
1030  * @neigh_node: next hop to forward packet to
1031  *
1032  * Returns true if both packets are consumed, false otherwise.
1033  */
1034 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1035                                    struct sk_buff *skb,
1036                                    struct ethhdr *ethhdr,
1037                                    struct batadv_nc_packet *nc_packet,
1038                                    struct batadv_neigh_node *neigh_node)
1039 {
1040         u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1041         struct sk_buff *skb_dest, *skb_src;
1042         struct batadv_unicast_packet *packet1;
1043         struct batadv_unicast_packet *packet2;
1044         struct batadv_coded_packet *coded_packet;
1045         struct batadv_neigh_node *neigh_tmp, *router_neigh;
1046         struct batadv_neigh_node *router_coding = NULL;
1047         struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1048         struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1049         u8 *first_source, *first_dest, *second_source, *second_dest;
1050         __be32 packet_id1, packet_id2;
1051         size_t count;
1052         bool res = false;
1053         int coding_len;
1054         int unicast_size = sizeof(*packet1);
1055         int coded_size = sizeof(*coded_packet);
1056         int header_add = coded_size - unicast_size;
1057
1058         /* TODO: do we need to consider the outgoing interface for
1059          * coded packets?
1060          */
1061         router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1062                                               BATADV_IF_DEFAULT);
1063         if (!router_neigh)
1064                 goto out;
1065
1066         router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1067                                                       BATADV_IF_DEFAULT);
1068         if (!router_neigh_ifinfo)
1069                 goto out;
1070
1071         neigh_tmp = nc_packet->neigh_node;
1072         router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1073                                                BATADV_IF_DEFAULT);
1074         if (!router_coding)
1075                 goto out;
1076
1077         router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1078                                                        BATADV_IF_DEFAULT);
1079         if (!router_coding_ifinfo)
1080                 goto out;
1081
1082         tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1083         tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1084         tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1085         tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1086
1087         /* Select one destination for the MAC-header dst-field based on
1088          * weighted TQ-values.
1089          */
1090         if (tq_weighted_neigh >= tq_weighted_coding) {
1091                 /* Destination from nc_packet is selected for MAC-header */
1092                 first_dest = nc_packet->nc_path->next_hop;
1093                 first_source = nc_packet->nc_path->prev_hop;
1094                 second_dest = neigh_node->addr;
1095                 second_source = ethhdr->h_source;
1096                 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1097                 packet2 = (struct batadv_unicast_packet *)skb->data;
1098                 packet_id1 = nc_packet->packet_id;
1099                 packet_id2 = batadv_skb_crc32(skb,
1100                                               skb->data + sizeof(*packet2));
1101         } else {
1102                 /* Destination for skb is selected for MAC-header */
1103                 first_dest = neigh_node->addr;
1104                 first_source = ethhdr->h_source;
1105                 second_dest = nc_packet->nc_path->next_hop;
1106                 second_source = nc_packet->nc_path->prev_hop;
1107                 packet1 = (struct batadv_unicast_packet *)skb->data;
1108                 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1109                 packet_id1 = batadv_skb_crc32(skb,
1110                                               skb->data + sizeof(*packet1));
1111                 packet_id2 = nc_packet->packet_id;
1112         }
1113
1114         /* Instead of zero padding the smallest data buffer, we
1115          * code into the largest.
1116          */
1117         if (skb->len <= nc_packet->skb->len) {
1118                 skb_dest = nc_packet->skb;
1119                 skb_src = skb;
1120         } else {
1121                 skb_dest = skb;
1122                 skb_src = nc_packet->skb;
1123         }
1124
1125         /* coding_len is used when decoding the packet shorter packet */
1126         coding_len = skb_src->len - unicast_size;
1127
1128         if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1129                 goto out;
1130
1131         skb_push(skb_dest, header_add);
1132
1133         coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1134         skb_reset_mac_header(skb_dest);
1135
1136         coded_packet->packet_type = BATADV_CODED;
1137         coded_packet->version = BATADV_COMPAT_VERSION;
1138         coded_packet->ttl = packet1->ttl;
1139
1140         /* Info about first unicast packet */
1141         ether_addr_copy(coded_packet->first_source, first_source);
1142         ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1143         coded_packet->first_crc = packet_id1;
1144         coded_packet->first_ttvn = packet1->ttvn;
1145
1146         /* Info about second unicast packet */
1147         ether_addr_copy(coded_packet->second_dest, second_dest);
1148         ether_addr_copy(coded_packet->second_source, second_source);
1149         ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1150         coded_packet->second_crc = packet_id2;
1151         coded_packet->second_ttl = packet2->ttl;
1152         coded_packet->second_ttvn = packet2->ttvn;
1153         coded_packet->coded_len = htons(coding_len);
1154
1155         /* This is where the magic happens: Code skb_src into skb_dest */
1156         batadv_nc_memxor(skb_dest->data + coded_size,
1157                          skb_src->data + unicast_size, coding_len);
1158
1159         /* Update counters accordingly */
1160         if (BATADV_SKB_CB(skb_src)->decoded &&
1161             BATADV_SKB_CB(skb_dest)->decoded) {
1162                 /* Both packets are recoded */
1163                 count = skb_src->len + ETH_HLEN;
1164                 count += skb_dest->len + ETH_HLEN;
1165                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1166                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1167         } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1168                    !BATADV_SKB_CB(skb_dest)->decoded) {
1169                 /* Both packets are newly coded */
1170                 count = skb_src->len + ETH_HLEN;
1171                 count += skb_dest->len + ETH_HLEN;
1172                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1173                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1174         } else if (BATADV_SKB_CB(skb_src)->decoded &&
1175                    !BATADV_SKB_CB(skb_dest)->decoded) {
1176                 /* skb_src recoded and skb_dest is newly coded */
1177                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1178                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1179                                    skb_src->len + ETH_HLEN);
1180                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1181                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1182                                    skb_dest->len + ETH_HLEN);
1183         } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1184                    BATADV_SKB_CB(skb_dest)->decoded) {
1185                 /* skb_src is newly coded and skb_dest is recoded */
1186                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1187                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1188                                    skb_src->len + ETH_HLEN);
1189                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1190                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1191                                    skb_dest->len + ETH_HLEN);
1192         }
1193
1194         /* skb_src is now coded into skb_dest, so free it */
1195         kfree_skb(skb_src);
1196
1197         /* avoid duplicate free of skb from nc_packet */
1198         nc_packet->skb = NULL;
1199         batadv_nc_packet_free(nc_packet);
1200
1201         /* Send the coded packet and return true */
1202         batadv_send_skb_packet(skb_dest, neigh_node->if_incoming, first_dest);
1203         res = true;
1204 out:
1205         if (router_neigh)
1206                 batadv_neigh_node_free_ref(router_neigh);
1207         if (router_coding)
1208                 batadv_neigh_node_free_ref(router_coding);
1209         if (router_neigh_ifinfo)
1210                 batadv_neigh_ifinfo_free_ref(router_neigh_ifinfo);
1211         if (router_coding_ifinfo)
1212                 batadv_neigh_ifinfo_free_ref(router_coding_ifinfo);
1213         return res;
1214 }
1215
1216 /**
1217  * batadv_nc_skb_coding_possible - true if a decoded skb is available at dst.
1218  * @skb: data skb to forward
1219  * @dst: destination mac address of the other skb to code with
1220  * @src: source mac address of skb
1221  *
1222  * Whenever we network code a packet we have to check whether we received it in
1223  * a network coded form. If so, we may not be able to use it for coding because
1224  * some neighbors may also have received (overheard) the packet in the network
1225  * coded form without being able to decode it. It is hard to know which of the
1226  * neighboring nodes was able to decode the packet, therefore we can only
1227  * re-code the packet if the source of the previous encoded packet is involved.
1228  * Since the source encoded the packet we can be certain it has all necessary
1229  * decode information.
1230  *
1231  * Returns true if coding of a decoded packet is allowed.
1232  */
1233 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1234 {
1235         if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1236                 return false;
1237         return true;
1238 }
1239
1240 /**
1241  * batadv_nc_path_search - Find the coding path matching in_nc_node and
1242  *  out_nc_node to retrieve a buffered packet that can be used for coding.
1243  * @bat_priv: the bat priv with all the soft interface information
1244  * @in_nc_node: pointer to skb next hop's neighbor nc node
1245  * @out_nc_node: pointer to skb source's neighbor nc node
1246  * @skb: data skb to forward
1247  * @eth_dst: next hop mac address of skb
1248  *
1249  * Returns true if coding of a decoded skb is allowed.
1250  */
1251 static struct batadv_nc_packet *
1252 batadv_nc_path_search(struct batadv_priv *bat_priv,
1253                       struct batadv_nc_node *in_nc_node,
1254                       struct batadv_nc_node *out_nc_node,
1255                       struct sk_buff *skb,
1256                       u8 *eth_dst)
1257 {
1258         struct batadv_nc_path *nc_path, nc_path_key;
1259         struct batadv_nc_packet *nc_packet_out = NULL;
1260         struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1261         struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1262         int idx;
1263
1264         if (!hash)
1265                 return NULL;
1266
1267         /* Create almost path key */
1268         batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1269                                out_nc_node->addr);
1270         idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1271
1272         /* Check for coding opportunities in this nc_path */
1273         rcu_read_lock();
1274         hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1275                 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1276                         continue;
1277
1278                 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1279                         continue;
1280
1281                 spin_lock_bh(&nc_path->packet_list_lock);
1282                 if (list_empty(&nc_path->packet_list)) {
1283                         spin_unlock_bh(&nc_path->packet_list_lock);
1284                         continue;
1285                 }
1286
1287                 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1288                                          &nc_path->packet_list, list) {
1289                         if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1290                                                            eth_dst,
1291                                                            in_nc_node->addr))
1292                                 continue;
1293
1294                         /* Coding opportunity is found! */
1295                         list_del(&nc_packet->list);
1296                         nc_packet_out = nc_packet;
1297                         break;
1298                 }
1299
1300                 spin_unlock_bh(&nc_path->packet_list_lock);
1301                 break;
1302         }
1303         rcu_read_unlock();
1304
1305         return nc_packet_out;
1306 }
1307
1308 /**
1309  * batadv_nc_skb_src_search - Loops through the list of neighoring nodes of the
1310  *  skb's sender (may be equal to the originator).
1311  * @bat_priv: the bat priv with all the soft interface information
1312  * @skb: data skb to forward
1313  * @eth_dst: next hop mac address of skb
1314  * @eth_src: source mac address of skb
1315  * @in_nc_node: pointer to skb next hop's neighbor nc node
1316  *
1317  * Returns an nc packet if a suitable coding packet was found, NULL otherwise.
1318  */
1319 static struct batadv_nc_packet *
1320 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1321                          struct sk_buff *skb,
1322                          u8 *eth_dst,
1323                          u8 *eth_src,
1324                          struct batadv_nc_node *in_nc_node)
1325 {
1326         struct batadv_orig_node *orig_node;
1327         struct batadv_nc_node *out_nc_node;
1328         struct batadv_nc_packet *nc_packet = NULL;
1329
1330         orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1331         if (!orig_node)
1332                 return NULL;
1333
1334         rcu_read_lock();
1335         list_for_each_entry_rcu(out_nc_node,
1336                                 &orig_node->out_coding_list, list) {
1337                 /* Check if the skb is decoded and if recoding is possible */
1338                 if (!batadv_nc_skb_coding_possible(skb,
1339                                                    out_nc_node->addr, eth_src))
1340                         continue;
1341
1342                 /* Search for an opportunity in this nc_path */
1343                 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1344                                                   out_nc_node, skb, eth_dst);
1345                 if (nc_packet)
1346                         break;
1347         }
1348         rcu_read_unlock();
1349
1350         batadv_orig_node_free_ref(orig_node);
1351         return nc_packet;
1352 }
1353
1354 /**
1355  * batadv_nc_skb_store_before_coding - set the ethernet src and dst of the
1356  *  unicast skb before it is stored for use in later decoding
1357  * @bat_priv: the bat priv with all the soft interface information
1358  * @skb: data skb to store
1359  * @eth_dst_new: new destination mac address of skb
1360  */
1361 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1362                                               struct sk_buff *skb,
1363                                               u8 *eth_dst_new)
1364 {
1365         struct ethhdr *ethhdr;
1366
1367         /* Copy skb header to change the mac header */
1368         skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1369         if (!skb)
1370                 return;
1371
1372         /* Set the mac header as if we actually sent the packet uncoded */
1373         ethhdr = eth_hdr(skb);
1374         ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1375         ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1376
1377         /* Set data pointer to MAC header to mimic packets from our tx path */
1378         skb_push(skb, ETH_HLEN);
1379
1380         /* Add the packet to the decoding packet pool */
1381         batadv_nc_skb_store_for_decoding(bat_priv, skb);
1382
1383         /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1384          * our ref
1385          */
1386         kfree_skb(skb);
1387 }
1388
1389 /**
1390  * batadv_nc_skb_dst_search - Loops through list of neighboring nodes to dst.
1391  * @skb: data skb to forward
1392  * @neigh_node: next hop to forward packet to
1393  * @ethhdr: pointer to the ethernet header inside the skb
1394  *
1395  * Loops through list of neighboring nodes the next hop has a good connection to
1396  * (receives OGMs with a sufficient quality). We need to find a neighbor of our
1397  * next hop that potentially sent a packet which our next hop also received
1398  * (overheard) and has stored for later decoding.
1399  *
1400  * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1401  */
1402 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1403                                      struct batadv_neigh_node *neigh_node,
1404                                      struct ethhdr *ethhdr)
1405 {
1406         struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1407         struct batadv_priv *bat_priv = netdev_priv(netdev);
1408         struct batadv_orig_node *orig_node = neigh_node->orig_node;
1409         struct batadv_nc_node *nc_node;
1410         struct batadv_nc_packet *nc_packet = NULL;
1411
1412         rcu_read_lock();
1413         list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1414                 /* Search for coding opportunity with this in_nc_node */
1415                 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1416                                                      neigh_node->addr,
1417                                                      ethhdr->h_source, nc_node);
1418
1419                 /* Opportunity was found, so stop searching */
1420                 if (nc_packet)
1421                         break;
1422         }
1423         rcu_read_unlock();
1424
1425         if (!nc_packet)
1426                 return false;
1427
1428         /* Save packets for later decoding */
1429         batadv_nc_skb_store_before_coding(bat_priv, skb,
1430                                           neigh_node->addr);
1431         batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1432                                           nc_packet->neigh_node->addr);
1433
1434         /* Code and send packets */
1435         if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1436                                    neigh_node))
1437                 return true;
1438
1439         /* out of mem ? Coding failed - we have to free the buffered packet
1440          * to avoid memleaks. The skb passed as argument will be dealt with
1441          * by the calling function.
1442          */
1443         batadv_nc_send_packet(nc_packet);
1444         return false;
1445 }
1446
1447 /**
1448  * batadv_nc_skb_add_to_path - buffer skb for later encoding / decoding
1449  * @skb: skb to add to path
1450  * @nc_path: path to add skb to
1451  * @neigh_node: next hop to forward packet to
1452  * @packet_id: checksum to identify packet
1453  *
1454  * Returns true if the packet was buffered or false in case of an error.
1455  */
1456 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1457                                       struct batadv_nc_path *nc_path,
1458                                       struct batadv_neigh_node *neigh_node,
1459                                       __be32 packet_id)
1460 {
1461         struct batadv_nc_packet *nc_packet;
1462
1463         nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1464         if (!nc_packet)
1465                 return false;
1466
1467         /* Initialize nc_packet */
1468         nc_packet->timestamp = jiffies;
1469         nc_packet->packet_id = packet_id;
1470         nc_packet->skb = skb;
1471         nc_packet->neigh_node = neigh_node;
1472         nc_packet->nc_path = nc_path;
1473
1474         /* Add coding packet to list */
1475         spin_lock_bh(&nc_path->packet_list_lock);
1476         list_add_tail(&nc_packet->list, &nc_path->packet_list);
1477         spin_unlock_bh(&nc_path->packet_list_lock);
1478
1479         return true;
1480 }
1481
1482 /**
1483  * batadv_nc_skb_forward - try to code a packet or add it to the coding packet
1484  *  buffer
1485  * @skb: data skb to forward
1486  * @neigh_node: next hop to forward packet to
1487  *
1488  * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1489  */
1490 bool batadv_nc_skb_forward(struct sk_buff *skb,
1491                            struct batadv_neigh_node *neigh_node)
1492 {
1493         const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1494         struct batadv_priv *bat_priv = netdev_priv(netdev);
1495         struct batadv_unicast_packet *packet;
1496         struct batadv_nc_path *nc_path;
1497         struct ethhdr *ethhdr = eth_hdr(skb);
1498         __be32 packet_id;
1499         u8 *payload;
1500
1501         /* Check if network coding is enabled */
1502         if (!atomic_read(&bat_priv->network_coding))
1503                 goto out;
1504
1505         /* We only handle unicast packets */
1506         payload = skb_network_header(skb);
1507         packet = (struct batadv_unicast_packet *)payload;
1508         if (packet->packet_type != BATADV_UNICAST)
1509                 goto out;
1510
1511         /* Try to find a coding opportunity and send the skb if one is found */
1512         if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1513                 return true;
1514
1515         /* Find or create a nc_path for this src-dst pair */
1516         nc_path = batadv_nc_get_path(bat_priv,
1517                                      bat_priv->nc.coding_hash,
1518                                      ethhdr->h_source,
1519                                      neigh_node->addr);
1520
1521         if (!nc_path)
1522                 goto out;
1523
1524         /* Add skb to nc_path */
1525         packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1526         if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1527                 goto free_nc_path;
1528
1529         /* Packet is consumed */
1530         return true;
1531
1532 free_nc_path:
1533         batadv_nc_path_free_ref(nc_path);
1534 out:
1535         /* Packet is not consumed */
1536         return false;
1537 }
1538
1539 /**
1540  * batadv_nc_skb_store_for_decoding - save a clone of the skb which can be used
1541  *  when decoding coded packets
1542  * @bat_priv: the bat priv with all the soft interface information
1543  * @skb: data skb to store
1544  */
1545 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1546                                       struct sk_buff *skb)
1547 {
1548         struct batadv_unicast_packet *packet;
1549         struct batadv_nc_path *nc_path;
1550         struct ethhdr *ethhdr = eth_hdr(skb);
1551         __be32 packet_id;
1552         u8 *payload;
1553
1554         /* Check if network coding is enabled */
1555         if (!atomic_read(&bat_priv->network_coding))
1556                 goto out;
1557
1558         /* Check for supported packet type */
1559         payload = skb_network_header(skb);
1560         packet = (struct batadv_unicast_packet *)payload;
1561         if (packet->packet_type != BATADV_UNICAST)
1562                 goto out;
1563
1564         /* Find existing nc_path or create a new */
1565         nc_path = batadv_nc_get_path(bat_priv,
1566                                      bat_priv->nc.decoding_hash,
1567                                      ethhdr->h_source,
1568                                      ethhdr->h_dest);
1569
1570         if (!nc_path)
1571                 goto out;
1572
1573         /* Clone skb and adjust skb->data to point at batman header */
1574         skb = skb_clone(skb, GFP_ATOMIC);
1575         if (unlikely(!skb))
1576                 goto free_nc_path;
1577
1578         if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1579                 goto free_skb;
1580
1581         if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1582                 goto free_skb;
1583
1584         /* Add skb to nc_path */
1585         packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1586         if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1587                 goto free_skb;
1588
1589         batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1590         return;
1591
1592 free_skb:
1593         kfree_skb(skb);
1594 free_nc_path:
1595         batadv_nc_path_free_ref(nc_path);
1596 out:
1597         return;
1598 }
1599
1600 /**
1601  * batadv_nc_skb_store_sniffed_unicast - check if a received unicast packet
1602  *  should be saved in the decoding buffer and, if so, store it there
1603  * @bat_priv: the bat priv with all the soft interface information
1604  * @skb: unicast skb to store
1605  */
1606 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1607                                          struct sk_buff *skb)
1608 {
1609         struct ethhdr *ethhdr = eth_hdr(skb);
1610
1611         if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1612                 return;
1613
1614         /* Set data pointer to MAC header to mimic packets from our tx path */
1615         skb_push(skb, ETH_HLEN);
1616
1617         batadv_nc_skb_store_for_decoding(bat_priv, skb);
1618 }
1619
1620 /**
1621  * batadv_nc_skb_decode_packet - decode given skb using the decode data stored
1622  *  in nc_packet
1623  * @bat_priv: the bat priv with all the soft interface information
1624  * @skb: unicast skb to decode
1625  * @nc_packet: decode data needed to decode the skb
1626  *
1627  * Returns pointer to decoded unicast packet if the packet was decoded or NULL
1628  * in case of an error.
1629  */
1630 static struct batadv_unicast_packet *
1631 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1632                             struct batadv_nc_packet *nc_packet)
1633 {
1634         const int h_size = sizeof(struct batadv_unicast_packet);
1635         const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1636         struct batadv_unicast_packet *unicast_packet;
1637         struct batadv_coded_packet coded_packet_tmp;
1638         struct ethhdr *ethhdr, ethhdr_tmp;
1639         u8 *orig_dest, ttl, ttvn;
1640         unsigned int coding_len;
1641         int err;
1642
1643         /* Save headers temporarily */
1644         memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1645         memcpy(&ethhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1646
1647         if (skb_cow(skb, 0) < 0)
1648                 return NULL;
1649
1650         if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1651                 return NULL;
1652
1653         /* Data points to batman header, so set mac header 14 bytes before
1654          * and network to data
1655          */
1656         skb_set_mac_header(skb, -ETH_HLEN);
1657         skb_reset_network_header(skb);
1658
1659         /* Reconstruct original mac header */
1660         ethhdr = eth_hdr(skb);
1661         *ethhdr = ethhdr_tmp;
1662
1663         /* Select the correct unicast header information based on the location
1664          * of our mac address in the coded_packet header
1665          */
1666         if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1667                 /* If we are the second destination the packet was overheard,
1668                  * so the Ethernet address must be copied to h_dest and
1669                  * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1670                  */
1671                 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1672                 skb->pkt_type = PACKET_HOST;
1673
1674                 orig_dest = coded_packet_tmp.second_orig_dest;
1675                 ttl = coded_packet_tmp.second_ttl;
1676                 ttvn = coded_packet_tmp.second_ttvn;
1677         } else {
1678                 orig_dest = coded_packet_tmp.first_orig_dest;
1679                 ttl = coded_packet_tmp.ttl;
1680                 ttvn = coded_packet_tmp.first_ttvn;
1681         }
1682
1683         coding_len = ntohs(coded_packet_tmp.coded_len);
1684
1685         if (coding_len > skb->len)
1686                 return NULL;
1687
1688         /* Here the magic is reversed:
1689          *   extract the missing packet from the received coded packet
1690          */
1691         batadv_nc_memxor(skb->data + h_size,
1692                          nc_packet->skb->data + h_size,
1693                          coding_len);
1694
1695         /* Resize decoded skb if decoded with larger packet */
1696         if (nc_packet->skb->len > coding_len + h_size) {
1697                 err = pskb_trim_rcsum(skb, coding_len + h_size);
1698                 if (err)
1699                         return NULL;
1700         }
1701
1702         /* Create decoded unicast packet */
1703         unicast_packet = (struct batadv_unicast_packet *)skb->data;
1704         unicast_packet->packet_type = BATADV_UNICAST;
1705         unicast_packet->version = BATADV_COMPAT_VERSION;
1706         unicast_packet->ttl = ttl;
1707         ether_addr_copy(unicast_packet->dest, orig_dest);
1708         unicast_packet->ttvn = ttvn;
1709
1710         batadv_nc_packet_free(nc_packet);
1711         return unicast_packet;
1712 }
1713
1714 /**
1715  * batadv_nc_find_decoding_packet - search through buffered decoding data to
1716  *  find the data needed to decode the coded packet
1717  * @bat_priv: the bat priv with all the soft interface information
1718  * @ethhdr: pointer to the ethernet header inside the coded packet
1719  * @coded: coded packet we try to find decode data for
1720  *
1721  * Returns pointer to nc packet if the needed data was found or NULL otherwise.
1722  */
1723 static struct batadv_nc_packet *
1724 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1725                                struct ethhdr *ethhdr,
1726                                struct batadv_coded_packet *coded)
1727 {
1728         struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1729         struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1730         struct batadv_nc_path *nc_path, nc_path_key;
1731         u8 *dest, *source;
1732         __be32 packet_id;
1733         int index;
1734
1735         if (!hash)
1736                 return NULL;
1737
1738         /* Select the correct packet id based on the location of our mac-addr */
1739         dest = ethhdr->h_source;
1740         if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1741                 source = coded->second_source;
1742                 packet_id = coded->second_crc;
1743         } else {
1744                 source = coded->first_source;
1745                 packet_id = coded->first_crc;
1746         }
1747
1748         batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1749         index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1750
1751         /* Search for matching coding path */
1752         rcu_read_lock();
1753         hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1754                 /* Find matching nc_packet */
1755                 spin_lock_bh(&nc_path->packet_list_lock);
1756                 list_for_each_entry(tmp_nc_packet,
1757                                     &nc_path->packet_list, list) {
1758                         if (packet_id == tmp_nc_packet->packet_id) {
1759                                 list_del(&tmp_nc_packet->list);
1760
1761                                 nc_packet = tmp_nc_packet;
1762                                 break;
1763                         }
1764                 }
1765                 spin_unlock_bh(&nc_path->packet_list_lock);
1766
1767                 if (nc_packet)
1768                         break;
1769         }
1770         rcu_read_unlock();
1771
1772         if (!nc_packet)
1773                 batadv_dbg(BATADV_DBG_NC, bat_priv,
1774                            "No decoding packet found for %u\n", packet_id);
1775
1776         return nc_packet;
1777 }
1778
1779 /**
1780  * batadv_nc_recv_coded_packet - try to decode coded packet and enqueue the
1781  *  resulting unicast packet
1782  * @skb: incoming coded packet
1783  * @recv_if: pointer to interface this packet was received on
1784  */
1785 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1786                                        struct batadv_hard_iface *recv_if)
1787 {
1788         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1789         struct batadv_unicast_packet *unicast_packet;
1790         struct batadv_coded_packet *coded_packet;
1791         struct batadv_nc_packet *nc_packet;
1792         struct ethhdr *ethhdr;
1793         int hdr_size = sizeof(*coded_packet);
1794
1795         /* Check if network coding is enabled */
1796         if (!atomic_read(&bat_priv->network_coding))
1797                 return NET_RX_DROP;
1798
1799         /* Make sure we can access (and remove) header */
1800         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1801                 return NET_RX_DROP;
1802
1803         coded_packet = (struct batadv_coded_packet *)skb->data;
1804         ethhdr = eth_hdr(skb);
1805
1806         /* Verify frame is destined for us */
1807         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1808             !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1809                 return NET_RX_DROP;
1810
1811         /* Update stat counter */
1812         if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1813                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1814
1815         nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1816                                                    coded_packet);
1817         if (!nc_packet) {
1818                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1819                 return NET_RX_DROP;
1820         }
1821
1822         /* Make skb's linear, because decoding accesses the entire buffer */
1823         if (skb_linearize(skb) < 0)
1824                 goto free_nc_packet;
1825
1826         if (skb_linearize(nc_packet->skb) < 0)
1827                 goto free_nc_packet;
1828
1829         /* Decode the packet */
1830         unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1831         if (!unicast_packet) {
1832                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1833                 goto free_nc_packet;
1834         }
1835
1836         /* Mark packet as decoded to do correct recoding when forwarding */
1837         BATADV_SKB_CB(skb)->decoded = true;
1838         batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1839         batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1840                            skb->len + ETH_HLEN);
1841         return batadv_recv_unicast_packet(skb, recv_if);
1842
1843 free_nc_packet:
1844         batadv_nc_packet_free(nc_packet);
1845         return NET_RX_DROP;
1846 }
1847
1848 /**
1849  * batadv_nc_mesh_free - clean up network coding memory
1850  * @bat_priv: the bat priv with all the soft interface information
1851  */
1852 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1853 {
1854         batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1855         batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1856         cancel_delayed_work_sync(&bat_priv->nc.work);
1857
1858         batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1859         batadv_hash_destroy(bat_priv->nc.coding_hash);
1860         batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1861         batadv_hash_destroy(bat_priv->nc.decoding_hash);
1862 }
1863
1864 /**
1865  * batadv_nc_nodes_seq_print_text - print the nc node information
1866  * @seq: seq file to print on
1867  * @offset: not used
1868  */
1869 int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
1870 {
1871         struct net_device *net_dev = (struct net_device *)seq->private;
1872         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1873         struct batadv_hashtable *hash = bat_priv->orig_hash;
1874         struct batadv_hard_iface *primary_if;
1875         struct hlist_head *head;
1876         struct batadv_orig_node *orig_node;
1877         struct batadv_nc_node *nc_node;
1878         int i;
1879
1880         primary_if = batadv_seq_print_text_primary_if_get(seq);
1881         if (!primary_if)
1882                 goto out;
1883
1884         /* Traverse list of originators */
1885         for (i = 0; i < hash->size; i++) {
1886                 head = &hash->table[i];
1887
1888                 /* For each orig_node in this bin */
1889                 rcu_read_lock();
1890                 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1891                         /* no need to print the orig node if it does not have
1892                          * network coding neighbors
1893                          */
1894                         if (list_empty(&orig_node->in_coding_list) &&
1895                             list_empty(&orig_node->out_coding_list))
1896                                 continue;
1897
1898                         seq_printf(seq, "Node:      %pM\n", orig_node->orig);
1899
1900                         seq_puts(seq, " Ingoing:  ");
1901                         /* For each in_nc_node to this orig_node */
1902                         list_for_each_entry_rcu(nc_node,
1903                                                 &orig_node->in_coding_list,
1904                                                 list)
1905                                 seq_printf(seq, "%pM ",
1906                                            nc_node->addr);
1907                         seq_puts(seq, "\n");
1908
1909                         seq_puts(seq, " Outgoing: ");
1910                         /* For out_nc_node to this orig_node */
1911                         list_for_each_entry_rcu(nc_node,
1912                                                 &orig_node->out_coding_list,
1913                                                 list)
1914                                 seq_printf(seq, "%pM ",
1915                                            nc_node->addr);
1916                         seq_puts(seq, "\n\n");
1917                 }
1918                 rcu_read_unlock();
1919         }
1920
1921 out:
1922         if (primary_if)
1923                 batadv_hardif_free_ref(primary_if);
1924         return 0;
1925 }
1926
1927 /**
1928  * batadv_nc_init_debugfs - create nc folder and related files in debugfs
1929  * @bat_priv: the bat priv with all the soft interface information
1930  */
1931 int batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
1932 {
1933         struct dentry *nc_dir, *file;
1934
1935         nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
1936         if (!nc_dir)
1937                 goto out;
1938
1939         file = debugfs_create_u8("min_tq", S_IRUGO | S_IWUSR, nc_dir,
1940                                  &bat_priv->nc.min_tq);
1941         if (!file)
1942                 goto out;
1943
1944         file = debugfs_create_u32("max_fwd_delay", S_IRUGO | S_IWUSR, nc_dir,
1945                                   &bat_priv->nc.max_fwd_delay);
1946         if (!file)
1947                 goto out;
1948
1949         file = debugfs_create_u32("max_buffer_time", S_IRUGO | S_IWUSR, nc_dir,
1950                                   &bat_priv->nc.max_buffer_time);
1951         if (!file)
1952                 goto out;
1953
1954         return 0;
1955
1956 out:
1957         return -ENOMEM;
1958 }