Merge tag 'fixes-for-v3.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux/fpc-iii.git] / net / batman-adv / network-coding.c
blob8d04d174669ed29c467436d33b099ad5d0ca13c4
1 /* Copyright (C) 2012-2014 B.A.T.M.A.N. contributors:
3 * Martin Hundebøll, Jeppe Ledet-Pedersen
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.
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.
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/>.
18 #include <linux/debugfs.h>
20 #include "main.h"
21 #include "hash.h"
22 #include "network-coding.h"
23 #include "send.h"
24 #include "originator.h"
25 #include "hard-interface.h"
26 #include "routing.h"
28 static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
29 static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
31 static void batadv_nc_worker(struct work_struct *work);
32 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
33 struct batadv_hard_iface *recv_if);
35 /**
36 * batadv_nc_init - one-time initialization for network coding
38 int __init batadv_nc_init(void)
40 int ret;
42 /* Register our packet type */
43 ret = batadv_recv_handler_register(BATADV_CODED,
44 batadv_nc_recv_coded_packet);
46 return ret;
49 /**
50 * batadv_nc_start_timer - initialise the nc periodic worker
51 * @bat_priv: the bat priv with all the soft interface information
53 static void batadv_nc_start_timer(struct batadv_priv *bat_priv)
55 queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work,
56 msecs_to_jiffies(10));
59 /**
60 * batadv_nc_tvlv_container_update - update the network coding tvlv container
61 * after network coding setting change
62 * @bat_priv: the bat priv with all the soft interface information
64 static void batadv_nc_tvlv_container_update(struct batadv_priv *bat_priv)
66 char nc_mode;
68 nc_mode = atomic_read(&bat_priv->network_coding);
70 switch (nc_mode) {
71 case 0:
72 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
73 break;
74 case 1:
75 batadv_tvlv_container_register(bat_priv, BATADV_TVLV_NC, 1,
76 NULL, 0);
77 break;
81 /**
82 * batadv_nc_status_update - update the network coding tvlv container after
83 * network coding setting change
84 * @net_dev: the soft interface net device
86 void batadv_nc_status_update(struct net_device *net_dev)
88 struct batadv_priv *bat_priv = netdev_priv(net_dev);
90 batadv_nc_tvlv_container_update(bat_priv);
93 /**
94 * batadv_nc_tvlv_ogm_handler_v1 - process incoming nc tvlv container
95 * @bat_priv: the bat priv with all the soft interface information
96 * @orig: the orig_node of the ogm
97 * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
98 * @tvlv_value: tvlv buffer containing the gateway data
99 * @tvlv_value_len: tvlv buffer length
101 static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
102 struct batadv_orig_node *orig,
103 uint8_t flags,
104 void *tvlv_value,
105 uint16_t tvlv_value_len)
107 if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
108 orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_NC;
109 else
110 orig->capabilities |= BATADV_ORIG_CAPA_HAS_NC;
114 * batadv_nc_mesh_init - initialise coding hash table and start house keeping
115 * @bat_priv: the bat priv with all the soft interface information
117 int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
119 bat_priv->nc.timestamp_fwd_flush = jiffies;
120 bat_priv->nc.timestamp_sniffed_purge = jiffies;
122 if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
123 return 0;
125 bat_priv->nc.coding_hash = batadv_hash_new(128);
126 if (!bat_priv->nc.coding_hash)
127 goto err;
129 batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
130 &batadv_nc_coding_hash_lock_class_key);
132 bat_priv->nc.decoding_hash = batadv_hash_new(128);
133 if (!bat_priv->nc.decoding_hash)
134 goto err;
136 batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
137 &batadv_nc_decoding_hash_lock_class_key);
139 INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
140 batadv_nc_start_timer(bat_priv);
142 batadv_tvlv_handler_register(bat_priv, batadv_nc_tvlv_ogm_handler_v1,
143 NULL, BATADV_TVLV_NC, 1,
144 BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
145 batadv_nc_tvlv_container_update(bat_priv);
146 return 0;
148 err:
149 return -ENOMEM;
153 * batadv_nc_init_bat_priv - initialise the nc specific bat_priv variables
154 * @bat_priv: the bat priv with all the soft interface information
156 void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
158 atomic_set(&bat_priv->network_coding, 1);
159 bat_priv->nc.min_tq = 200;
160 bat_priv->nc.max_fwd_delay = 10;
161 bat_priv->nc.max_buffer_time = 200;
165 * batadv_nc_init_orig - initialise the nc fields of an orig_node
166 * @orig_node: the orig_node which is going to be initialised
168 void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
170 INIT_LIST_HEAD(&orig_node->in_coding_list);
171 INIT_LIST_HEAD(&orig_node->out_coding_list);
172 spin_lock_init(&orig_node->in_coding_list_lock);
173 spin_lock_init(&orig_node->out_coding_list_lock);
177 * batadv_nc_node_free_rcu - rcu callback to free an nc node and remove
178 * its refcount on the orig_node
179 * @rcu: rcu pointer of the nc node
181 static void batadv_nc_node_free_rcu(struct rcu_head *rcu)
183 struct batadv_nc_node *nc_node;
185 nc_node = container_of(rcu, struct batadv_nc_node, rcu);
186 batadv_orig_node_free_ref(nc_node->orig_node);
187 kfree(nc_node);
191 * batadv_nc_node_free_ref - decrements the nc node refcounter and possibly
192 * frees it
193 * @nc_node: the nc node to free
195 static void batadv_nc_node_free_ref(struct batadv_nc_node *nc_node)
197 if (atomic_dec_and_test(&nc_node->refcount))
198 call_rcu(&nc_node->rcu, batadv_nc_node_free_rcu);
202 * batadv_nc_path_free_ref - decrements the nc path refcounter and possibly
203 * frees it
204 * @nc_path: the nc node to free
206 static void batadv_nc_path_free_ref(struct batadv_nc_path *nc_path)
208 if (atomic_dec_and_test(&nc_path->refcount))
209 kfree_rcu(nc_path, rcu);
213 * batadv_nc_packet_free - frees nc packet
214 * @nc_packet: the nc packet to free
216 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet)
218 if (nc_packet->skb)
219 kfree_skb(nc_packet->skb);
221 batadv_nc_path_free_ref(nc_packet->nc_path);
222 kfree(nc_packet);
226 * batadv_nc_to_purge_nc_node - checks whether an nc node has to be purged
227 * @bat_priv: the bat priv with all the soft interface information
228 * @nc_node: the nc node to check
230 * Returns true if the entry has to be purged now, false otherwise
232 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
233 struct batadv_nc_node *nc_node)
235 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
236 return true;
238 return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
242 * batadv_nc_to_purge_nc_path_coding - checks whether an nc path has timed out
243 * @bat_priv: the bat priv with all the soft interface information
244 * @nc_path: the nc path to check
246 * Returns true if the entry has to be purged now, false otherwise
248 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
249 struct batadv_nc_path *nc_path)
251 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
252 return true;
254 /* purge the path when no packets has been added for 10 times the
255 * max_fwd_delay time
257 return batadv_has_timed_out(nc_path->last_valid,
258 bat_priv->nc.max_fwd_delay * 10);
262 * batadv_nc_to_purge_nc_path_decoding - checks whether an nc path has timed out
263 * @bat_priv: the bat priv with all the soft interface information
264 * @nc_path: the nc path to check
266 * Returns true if the entry has to be purged now, false otherwise
268 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
269 struct batadv_nc_path *nc_path)
271 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
272 return true;
274 /* purge the path when no packets has been added for 10 times the
275 * max_buffer time
277 return batadv_has_timed_out(nc_path->last_valid,
278 bat_priv->nc.max_buffer_time*10);
282 * batadv_nc_purge_orig_nc_nodes - go through list of nc nodes and purge stale
283 * entries
284 * @bat_priv: the bat priv with all the soft interface information
285 * @list: list of nc nodes
286 * @lock: nc node list lock
287 * @to_purge: function in charge to decide whether an entry has to be purged or
288 * not. This function takes the nc node as argument and has to return
289 * a boolean value: true if the entry has to be deleted, false
290 * otherwise
292 static void
293 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
294 struct list_head *list,
295 spinlock_t *lock,
296 bool (*to_purge)(struct batadv_priv *,
297 struct batadv_nc_node *))
299 struct batadv_nc_node *nc_node, *nc_node_tmp;
301 /* For each nc_node in list */
302 spin_lock_bh(lock);
303 list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
304 /* if an helper function has been passed as parameter,
305 * ask it if the entry has to be purged or not
307 if (to_purge && !to_purge(bat_priv, nc_node))
308 continue;
310 batadv_dbg(BATADV_DBG_NC, bat_priv,
311 "Removing nc_node %pM -> %pM\n",
312 nc_node->addr, nc_node->orig_node->orig);
313 list_del_rcu(&nc_node->list);
314 batadv_nc_node_free_ref(nc_node);
316 spin_unlock_bh(lock);
320 * batadv_nc_purge_orig - purges all nc node data attached of the given
321 * originator
322 * @bat_priv: the bat priv with all the soft interface information
323 * @orig_node: orig_node with the nc node entries to be purged
324 * @to_purge: function in charge to decide whether an entry has to be purged or
325 * not. This function takes the nc node as argument and has to return
326 * a boolean value: true is the entry has to be deleted, false
327 * otherwise
329 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
330 struct batadv_orig_node *orig_node,
331 bool (*to_purge)(struct batadv_priv *,
332 struct batadv_nc_node *))
334 /* Check ingoing nc_node's of this orig_node */
335 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
336 &orig_node->in_coding_list_lock,
337 to_purge);
339 /* Check outgoing nc_node's of this orig_node */
340 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
341 &orig_node->out_coding_list_lock,
342 to_purge);
346 * batadv_nc_purge_orig_hash - traverse entire originator hash to check if they
347 * have timed out nc nodes
348 * @bat_priv: the bat priv with all the soft interface information
350 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
352 struct batadv_hashtable *hash = bat_priv->orig_hash;
353 struct hlist_head *head;
354 struct batadv_orig_node *orig_node;
355 uint32_t i;
357 if (!hash)
358 return;
360 /* For each orig_node */
361 for (i = 0; i < hash->size; i++) {
362 head = &hash->table[i];
364 rcu_read_lock();
365 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
366 batadv_nc_purge_orig(bat_priv, orig_node,
367 batadv_nc_to_purge_nc_node);
368 rcu_read_unlock();
373 * batadv_nc_purge_paths - traverse all nc paths part of the hash and remove
374 * unused ones
375 * @bat_priv: the bat priv with all the soft interface information
376 * @hash: hash table containing the nc paths to check
377 * @to_purge: function in charge to decide whether an entry has to be purged or
378 * not. This function takes the nc node as argument and has to return
379 * a boolean value: true is the entry has to be deleted, false
380 * otherwise
382 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
383 struct batadv_hashtable *hash,
384 bool (*to_purge)(struct batadv_priv *,
385 struct batadv_nc_path *))
387 struct hlist_head *head;
388 struct hlist_node *node_tmp;
389 struct batadv_nc_path *nc_path;
390 spinlock_t *lock; /* Protects lists in hash */
391 uint32_t i;
393 for (i = 0; i < hash->size; i++) {
394 head = &hash->table[i];
395 lock = &hash->list_locks[i];
397 /* For each nc_path in this bin */
398 spin_lock_bh(lock);
399 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
400 /* if an helper function has been passed as parameter,
401 * ask it if the entry has to be purged or not
403 if (to_purge && !to_purge(bat_priv, nc_path))
404 continue;
406 /* purging an non-empty nc_path should never happen, but
407 * is observed under high CPU load. Delay the purging
408 * until next iteration to allow the packet_list to be
409 * emptied first.
411 if (!unlikely(list_empty(&nc_path->packet_list))) {
412 net_ratelimited_function(printk,
413 KERN_WARNING
414 "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
415 nc_path->prev_hop,
416 nc_path->next_hop);
417 continue;
420 /* nc_path is unused, so remove it */
421 batadv_dbg(BATADV_DBG_NC, bat_priv,
422 "Remove nc_path %pM -> %pM\n",
423 nc_path->prev_hop, nc_path->next_hop);
424 hlist_del_rcu(&nc_path->hash_entry);
425 batadv_nc_path_free_ref(nc_path);
427 spin_unlock_bh(lock);
432 * batadv_nc_hash_key_gen - computes the nc_path hash key
433 * @key: buffer to hold the final hash key
434 * @src: source ethernet mac address going into the hash key
435 * @dst: destination ethernet mac address going into the hash key
437 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
438 const char *dst)
440 memcpy(key->prev_hop, src, sizeof(key->prev_hop));
441 memcpy(key->next_hop, dst, sizeof(key->next_hop));
445 * batadv_nc_hash_choose - compute the hash value for an nc path
446 * @data: data to hash
447 * @size: size of the hash table
449 * Returns the selected index in the hash table for the given data.
451 static uint32_t batadv_nc_hash_choose(const void *data, uint32_t size)
453 const struct batadv_nc_path *nc_path = data;
454 uint32_t hash = 0;
456 hash = batadv_hash_bytes(hash, &nc_path->prev_hop,
457 sizeof(nc_path->prev_hop));
458 hash = batadv_hash_bytes(hash, &nc_path->next_hop,
459 sizeof(nc_path->next_hop));
461 hash += (hash << 3);
462 hash ^= (hash >> 11);
463 hash += (hash << 15);
465 return hash % size;
469 * batadv_nc_hash_compare - comparing function used in the network coding hash
470 * tables
471 * @node: node in the local table
472 * @data2: second object to compare the node to
474 * Returns 1 if the two entry are the same, 0 otherwise
476 static int batadv_nc_hash_compare(const struct hlist_node *node,
477 const void *data2)
479 const struct batadv_nc_path *nc_path1, *nc_path2;
481 nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
482 nc_path2 = data2;
484 /* Return 1 if the two keys are identical */
485 if (memcmp(nc_path1->prev_hop, nc_path2->prev_hop,
486 sizeof(nc_path1->prev_hop)) != 0)
487 return 0;
489 if (memcmp(nc_path1->next_hop, nc_path2->next_hop,
490 sizeof(nc_path1->next_hop)) != 0)
491 return 0;
493 return 1;
497 * batadv_nc_hash_find - search for an existing nc path and return it
498 * @hash: hash table containing the nc path
499 * @data: search key
501 * Returns the nc_path if found, NULL otherwise.
503 static struct batadv_nc_path *
504 batadv_nc_hash_find(struct batadv_hashtable *hash,
505 void *data)
507 struct hlist_head *head;
508 struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
509 int index;
511 if (!hash)
512 return NULL;
514 index = batadv_nc_hash_choose(data, hash->size);
515 head = &hash->table[index];
517 rcu_read_lock();
518 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
519 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
520 continue;
522 if (!atomic_inc_not_zero(&nc_path->refcount))
523 continue;
525 nc_path_tmp = nc_path;
526 break;
528 rcu_read_unlock();
530 return nc_path_tmp;
534 * batadv_nc_send_packet - send non-coded packet and free nc_packet struct
535 * @nc_packet: the nc packet to send
537 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
539 batadv_send_skb_packet(nc_packet->skb,
540 nc_packet->neigh_node->if_incoming,
541 nc_packet->nc_path->next_hop);
542 nc_packet->skb = NULL;
543 batadv_nc_packet_free(nc_packet);
547 * batadv_nc_sniffed_purge - Checks timestamp of given sniffed nc_packet.
548 * @bat_priv: the bat priv with all the soft interface information
549 * @nc_path: the nc path the packet belongs to
550 * @nc_packet: the nc packet to be checked
552 * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
553 * timeout. If so, the packet is no longer kept and the entry deleted from the
554 * queue. Has to be called with the appropriate locks.
556 * Returns false as soon as the entry in the fifo queue has not been timed out
557 * yet and true otherwise.
559 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
560 struct batadv_nc_path *nc_path,
561 struct batadv_nc_packet *nc_packet)
563 unsigned long timeout = bat_priv->nc.max_buffer_time;
564 bool res = false;
566 /* Packets are added to tail, so the remaining packets did not time
567 * out and we can stop processing the current queue
569 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
570 !batadv_has_timed_out(nc_packet->timestamp, timeout))
571 goto out;
573 /* purge nc packet */
574 list_del(&nc_packet->list);
575 batadv_nc_packet_free(nc_packet);
577 res = true;
579 out:
580 return res;
584 * batadv_nc_fwd_flush - Checks the timestamp of the given nc packet.
585 * @bat_priv: the bat priv with all the soft interface information
586 * @nc_path: the nc path the packet belongs to
587 * @nc_packet: the nc packet to be checked
589 * Checks whether the given nc packet has hit its forward timeout. If so, the
590 * packet is no longer delayed, immediately sent and the entry deleted from the
591 * queue. Has to be called with the appropriate locks.
593 * Returns false as soon as the entry in the fifo queue has not been timed out
594 * yet and true otherwise.
596 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
597 struct batadv_nc_path *nc_path,
598 struct batadv_nc_packet *nc_packet)
600 unsigned long timeout = bat_priv->nc.max_fwd_delay;
602 /* Packets are added to tail, so the remaining packets did not time
603 * out and we can stop processing the current queue
605 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
606 !batadv_has_timed_out(nc_packet->timestamp, timeout))
607 return false;
609 /* Send packet */
610 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
611 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
612 nc_packet->skb->len + ETH_HLEN);
613 list_del(&nc_packet->list);
614 batadv_nc_send_packet(nc_packet);
616 return true;
620 * batadv_nc_process_nc_paths - traverse given nc packet pool and free timed out
621 * nc packets
622 * @bat_priv: the bat priv with all the soft interface information
623 * @hash: to be processed hash table
624 * @process_fn: Function called to process given nc packet. Should return true
625 * to encourage this function to proceed with the next packet.
626 * Otherwise the rest of the current queue is skipped.
628 static void
629 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
630 struct batadv_hashtable *hash,
631 bool (*process_fn)(struct batadv_priv *,
632 struct batadv_nc_path *,
633 struct batadv_nc_packet *))
635 struct hlist_head *head;
636 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
637 struct batadv_nc_path *nc_path;
638 bool ret;
639 int i;
641 if (!hash)
642 return;
644 /* Loop hash table bins */
645 for (i = 0; i < hash->size; i++) {
646 head = &hash->table[i];
648 /* Loop coding paths */
649 rcu_read_lock();
650 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
651 /* Loop packets */
652 spin_lock_bh(&nc_path->packet_list_lock);
653 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
654 &nc_path->packet_list, list) {
655 ret = process_fn(bat_priv, nc_path, nc_packet);
656 if (!ret)
657 break;
659 spin_unlock_bh(&nc_path->packet_list_lock);
661 rcu_read_unlock();
666 * batadv_nc_worker - periodic task for house keeping related to network coding
667 * @work: kernel work struct
669 static void batadv_nc_worker(struct work_struct *work)
671 struct delayed_work *delayed_work;
672 struct batadv_priv_nc *priv_nc;
673 struct batadv_priv *bat_priv;
674 unsigned long timeout;
676 delayed_work = container_of(work, struct delayed_work, work);
677 priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
678 bat_priv = container_of(priv_nc, struct batadv_priv, nc);
680 batadv_nc_purge_orig_hash(bat_priv);
681 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
682 batadv_nc_to_purge_nc_path_coding);
683 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
684 batadv_nc_to_purge_nc_path_decoding);
686 timeout = bat_priv->nc.max_fwd_delay;
688 if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
689 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
690 batadv_nc_fwd_flush);
691 bat_priv->nc.timestamp_fwd_flush = jiffies;
694 if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
695 bat_priv->nc.max_buffer_time)) {
696 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
697 batadv_nc_sniffed_purge);
698 bat_priv->nc.timestamp_sniffed_purge = jiffies;
701 /* Schedule a new check */
702 batadv_nc_start_timer(bat_priv);
706 * batadv_can_nc_with_orig - checks whether the given orig node is suitable for
707 * coding or not
708 * @bat_priv: the bat priv with all the soft interface information
709 * @orig_node: neighboring orig node which may be used as nc candidate
710 * @ogm_packet: incoming ogm packet also used for the checks
712 * Returns true if:
713 * 1) The OGM must have the most recent sequence number.
714 * 2) The TTL must be decremented by one and only one.
715 * 3) The OGM must be received from the first hop from orig_node.
716 * 4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
718 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
719 struct batadv_orig_node *orig_node,
720 struct batadv_ogm_packet *ogm_packet)
722 struct batadv_orig_ifinfo *orig_ifinfo;
723 uint32_t last_real_seqno;
724 uint8_t last_ttl;
726 orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
727 if (!orig_ifinfo)
728 return false;
730 last_ttl = orig_ifinfo->last_ttl;
731 last_real_seqno = orig_ifinfo->last_real_seqno;
732 batadv_orig_ifinfo_free_ref(orig_ifinfo);
734 if (last_real_seqno != ntohl(ogm_packet->seqno))
735 return false;
736 if (last_ttl != ogm_packet->ttl + 1)
737 return false;
738 if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
739 return false;
740 if (ogm_packet->tq < bat_priv->nc.min_tq)
741 return false;
743 return true;
747 * batadv_nc_find_nc_node - search for an existing nc node and return it
748 * @orig_node: orig node originating the ogm packet
749 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
750 * (can be equal to orig_node)
751 * @in_coding: traverse incoming or outgoing network coding list
753 * Returns the nc_node if found, NULL otherwise.
755 static struct batadv_nc_node
756 *batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
757 struct batadv_orig_node *orig_neigh_node,
758 bool in_coding)
760 struct batadv_nc_node *nc_node, *nc_node_out = NULL;
761 struct list_head *list;
763 if (in_coding)
764 list = &orig_neigh_node->in_coding_list;
765 else
766 list = &orig_neigh_node->out_coding_list;
768 /* Traverse list of nc_nodes to orig_node */
769 rcu_read_lock();
770 list_for_each_entry_rcu(nc_node, list, list) {
771 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
772 continue;
774 if (!atomic_inc_not_zero(&nc_node->refcount))
775 continue;
777 /* Found a match */
778 nc_node_out = nc_node;
779 break;
781 rcu_read_unlock();
783 return nc_node_out;
787 * batadv_nc_get_nc_node - retrieves an nc node or creates the entry if it was
788 * not found
789 * @bat_priv: the bat priv with all the soft interface information
790 * @orig_node: orig node originating the ogm packet
791 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
792 * (can be equal to orig_node)
793 * @in_coding: traverse incoming or outgoing network coding list
795 * Returns the nc_node if found or created, NULL in case of an error.
797 static struct batadv_nc_node
798 *batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
799 struct batadv_orig_node *orig_node,
800 struct batadv_orig_node *orig_neigh_node,
801 bool in_coding)
803 struct batadv_nc_node *nc_node;
804 spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
805 struct list_head *list;
807 /* Check if nc_node is already added */
808 nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
810 /* Node found */
811 if (nc_node)
812 return nc_node;
814 nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
815 if (!nc_node)
816 return NULL;
818 if (!atomic_inc_not_zero(&orig_neigh_node->refcount))
819 goto free;
821 /* Initialize nc_node */
822 INIT_LIST_HEAD(&nc_node->list);
823 ether_addr_copy(nc_node->addr, orig_node->orig);
824 nc_node->orig_node = orig_neigh_node;
825 atomic_set(&nc_node->refcount, 2);
827 /* Select ingoing or outgoing coding node */
828 if (in_coding) {
829 lock = &orig_neigh_node->in_coding_list_lock;
830 list = &orig_neigh_node->in_coding_list;
831 } else {
832 lock = &orig_neigh_node->out_coding_list_lock;
833 list = &orig_neigh_node->out_coding_list;
836 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
837 nc_node->addr, nc_node->orig_node->orig);
839 /* Add nc_node to orig_node */
840 spin_lock_bh(lock);
841 list_add_tail_rcu(&nc_node->list, list);
842 spin_unlock_bh(lock);
844 return nc_node;
846 free:
847 kfree(nc_node);
848 return NULL;
852 * batadv_nc_update_nc_node - updates stored incoming and outgoing nc node structs
853 * (best called on incoming OGMs)
854 * @bat_priv: the bat priv with all the soft interface information
855 * @orig_node: orig node originating the ogm packet
856 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
857 * (can be equal to orig_node)
858 * @ogm_packet: incoming ogm packet
859 * @is_single_hop_neigh: orig_node is a single hop neighbor
861 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
862 struct batadv_orig_node *orig_node,
863 struct batadv_orig_node *orig_neigh_node,
864 struct batadv_ogm_packet *ogm_packet,
865 int is_single_hop_neigh)
867 struct batadv_nc_node *in_nc_node = NULL, *out_nc_node = NULL;
869 /* Check if network coding is enabled */
870 if (!atomic_read(&bat_priv->network_coding))
871 goto out;
873 /* check if orig node is network coding enabled */
874 if (!(orig_node->capabilities & BATADV_ORIG_CAPA_HAS_NC))
875 goto out;
877 /* accept ogms from 'good' neighbors and single hop neighbors */
878 if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
879 !is_single_hop_neigh)
880 goto out;
882 /* Add orig_node as in_nc_node on hop */
883 in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
884 orig_neigh_node, true);
885 if (!in_nc_node)
886 goto out;
888 in_nc_node->last_seen = jiffies;
890 /* Add hop as out_nc_node on orig_node */
891 out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
892 orig_node, false);
893 if (!out_nc_node)
894 goto out;
896 out_nc_node->last_seen = jiffies;
898 out:
899 if (in_nc_node)
900 batadv_nc_node_free_ref(in_nc_node);
901 if (out_nc_node)
902 batadv_nc_node_free_ref(out_nc_node);
906 * batadv_nc_get_path - get existing nc_path or allocate a new one
907 * @bat_priv: the bat priv with all the soft interface information
908 * @hash: hash table containing the nc path
909 * @src: ethernet source address - first half of the nc path search key
910 * @dst: ethernet destination address - second half of the nc path search key
912 * Returns pointer to nc_path if the path was found or created, returns NULL
913 * on error.
915 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
916 struct batadv_hashtable *hash,
917 uint8_t *src,
918 uint8_t *dst)
920 int hash_added;
921 struct batadv_nc_path *nc_path, nc_path_key;
923 batadv_nc_hash_key_gen(&nc_path_key, src, dst);
925 /* Search for existing nc_path */
926 nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
928 if (nc_path) {
929 /* Set timestamp to delay removal of nc_path */
930 nc_path->last_valid = jiffies;
931 return nc_path;
934 /* No existing nc_path was found; create a new */
935 nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
937 if (!nc_path)
938 return NULL;
940 /* Initialize nc_path */
941 INIT_LIST_HEAD(&nc_path->packet_list);
942 spin_lock_init(&nc_path->packet_list_lock);
943 atomic_set(&nc_path->refcount, 2);
944 nc_path->last_valid = jiffies;
945 ether_addr_copy(nc_path->next_hop, dst);
946 ether_addr_copy(nc_path->prev_hop, src);
948 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
949 nc_path->prev_hop,
950 nc_path->next_hop);
952 /* Add nc_path to hash table */
953 hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
954 batadv_nc_hash_choose, &nc_path_key,
955 &nc_path->hash_entry);
957 if (hash_added < 0) {
958 kfree(nc_path);
959 return NULL;
962 return nc_path;
966 * batadv_nc_random_weight_tq - scale the receivers TQ-value to avoid unfair
967 * selection of a receiver with slightly lower TQ than the other
968 * @tq: to be weighted tq value
970 static uint8_t batadv_nc_random_weight_tq(uint8_t tq)
972 uint8_t rand_val, rand_tq;
974 get_random_bytes(&rand_val, sizeof(rand_val));
976 /* randomize the estimated packet loss (max TQ - estimated TQ) */
977 rand_tq = rand_val * (BATADV_TQ_MAX_VALUE - tq);
979 /* normalize the randomized packet loss */
980 rand_tq /= BATADV_TQ_MAX_VALUE;
982 /* convert to (randomized) estimated tq again */
983 return BATADV_TQ_MAX_VALUE - rand_tq;
987 * batadv_nc_memxor - XOR destination with source
988 * @dst: byte array to XOR into
989 * @src: byte array to XOR from
990 * @len: length of destination array
992 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
994 unsigned int i;
996 for (i = 0; i < len; ++i)
997 dst[i] ^= src[i];
1001 * batadv_nc_code_packets - code a received unicast_packet with an nc packet
1002 * into a coded_packet and send it
1003 * @bat_priv: the bat priv with all the soft interface information
1004 * @skb: data skb to forward
1005 * @ethhdr: pointer to the ethernet header inside the skb
1006 * @nc_packet: structure containing the packet to the skb can be coded with
1007 * @neigh_node: next hop to forward packet to
1009 * Returns true if both packets are consumed, false otherwise.
1011 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1012 struct sk_buff *skb,
1013 struct ethhdr *ethhdr,
1014 struct batadv_nc_packet *nc_packet,
1015 struct batadv_neigh_node *neigh_node)
1017 uint8_t tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1018 struct sk_buff *skb_dest, *skb_src;
1019 struct batadv_unicast_packet *packet1;
1020 struct batadv_unicast_packet *packet2;
1021 struct batadv_coded_packet *coded_packet;
1022 struct batadv_neigh_node *neigh_tmp, *router_neigh;
1023 struct batadv_neigh_node *router_coding = NULL;
1024 struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1025 struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1026 uint8_t *first_source, *first_dest, *second_source, *second_dest;
1027 __be32 packet_id1, packet_id2;
1028 size_t count;
1029 bool res = false;
1030 int coding_len;
1031 int unicast_size = sizeof(*packet1);
1032 int coded_size = sizeof(*coded_packet);
1033 int header_add = coded_size - unicast_size;
1035 /* TODO: do we need to consider the outgoing interface for
1036 * coded packets?
1038 router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1039 BATADV_IF_DEFAULT);
1040 if (!router_neigh)
1041 goto out;
1043 router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1044 BATADV_IF_DEFAULT);
1045 if (!router_neigh_ifinfo)
1046 goto out;
1048 neigh_tmp = nc_packet->neigh_node;
1049 router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1050 BATADV_IF_DEFAULT);
1051 if (!router_coding)
1052 goto out;
1054 router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1055 BATADV_IF_DEFAULT);
1056 if (!router_coding_ifinfo)
1057 goto out;
1059 tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1060 tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1061 tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1062 tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1064 /* Select one destination for the MAC-header dst-field based on
1065 * weighted TQ-values.
1067 if (tq_weighted_neigh >= tq_weighted_coding) {
1068 /* Destination from nc_packet is selected for MAC-header */
1069 first_dest = nc_packet->nc_path->next_hop;
1070 first_source = nc_packet->nc_path->prev_hop;
1071 second_dest = neigh_node->addr;
1072 second_source = ethhdr->h_source;
1073 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1074 packet2 = (struct batadv_unicast_packet *)skb->data;
1075 packet_id1 = nc_packet->packet_id;
1076 packet_id2 = batadv_skb_crc32(skb,
1077 skb->data + sizeof(*packet2));
1078 } else {
1079 /* Destination for skb is selected for MAC-header */
1080 first_dest = neigh_node->addr;
1081 first_source = ethhdr->h_source;
1082 second_dest = nc_packet->nc_path->next_hop;
1083 second_source = nc_packet->nc_path->prev_hop;
1084 packet1 = (struct batadv_unicast_packet *)skb->data;
1085 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1086 packet_id1 = batadv_skb_crc32(skb,
1087 skb->data + sizeof(*packet1));
1088 packet_id2 = nc_packet->packet_id;
1091 /* Instead of zero padding the smallest data buffer, we
1092 * code into the largest.
1094 if (skb->len <= nc_packet->skb->len) {
1095 skb_dest = nc_packet->skb;
1096 skb_src = skb;
1097 } else {
1098 skb_dest = skb;
1099 skb_src = nc_packet->skb;
1102 /* coding_len is used when decoding the packet shorter packet */
1103 coding_len = skb_src->len - unicast_size;
1105 if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1106 goto out;
1108 skb_push(skb_dest, header_add);
1110 coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1111 skb_reset_mac_header(skb_dest);
1113 coded_packet->packet_type = BATADV_CODED;
1114 coded_packet->version = BATADV_COMPAT_VERSION;
1115 coded_packet->ttl = packet1->ttl;
1117 /* Info about first unicast packet */
1118 ether_addr_copy(coded_packet->first_source, first_source);
1119 ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1120 coded_packet->first_crc = packet_id1;
1121 coded_packet->first_ttvn = packet1->ttvn;
1123 /* Info about second unicast packet */
1124 ether_addr_copy(coded_packet->second_dest, second_dest);
1125 ether_addr_copy(coded_packet->second_source, second_source);
1126 ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1127 coded_packet->second_crc = packet_id2;
1128 coded_packet->second_ttl = packet2->ttl;
1129 coded_packet->second_ttvn = packet2->ttvn;
1130 coded_packet->coded_len = htons(coding_len);
1132 /* This is where the magic happens: Code skb_src into skb_dest */
1133 batadv_nc_memxor(skb_dest->data + coded_size,
1134 skb_src->data + unicast_size, coding_len);
1136 /* Update counters accordingly */
1137 if (BATADV_SKB_CB(skb_src)->decoded &&
1138 BATADV_SKB_CB(skb_dest)->decoded) {
1139 /* Both packets are recoded */
1140 count = skb_src->len + ETH_HLEN;
1141 count += skb_dest->len + ETH_HLEN;
1142 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1143 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1144 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1145 !BATADV_SKB_CB(skb_dest)->decoded) {
1146 /* Both packets are newly coded */
1147 count = skb_src->len + ETH_HLEN;
1148 count += skb_dest->len + ETH_HLEN;
1149 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1150 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1151 } else if (BATADV_SKB_CB(skb_src)->decoded &&
1152 !BATADV_SKB_CB(skb_dest)->decoded) {
1153 /* skb_src recoded and skb_dest is newly coded */
1154 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1155 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1156 skb_src->len + ETH_HLEN);
1157 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1158 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1159 skb_dest->len + ETH_HLEN);
1160 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1161 BATADV_SKB_CB(skb_dest)->decoded) {
1162 /* skb_src is newly coded and skb_dest is recoded */
1163 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1164 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1165 skb_src->len + ETH_HLEN);
1166 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1167 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1168 skb_dest->len + ETH_HLEN);
1171 /* skb_src is now coded into skb_dest, so free it */
1172 kfree_skb(skb_src);
1174 /* avoid duplicate free of skb from nc_packet */
1175 nc_packet->skb = NULL;
1176 batadv_nc_packet_free(nc_packet);
1178 /* Send the coded packet and return true */
1179 batadv_send_skb_packet(skb_dest, neigh_node->if_incoming, first_dest);
1180 res = true;
1181 out:
1182 if (router_neigh)
1183 batadv_neigh_node_free_ref(router_neigh);
1184 if (router_coding)
1185 batadv_neigh_node_free_ref(router_coding);
1186 if (router_neigh_ifinfo)
1187 batadv_neigh_ifinfo_free_ref(router_neigh_ifinfo);
1188 if (router_coding_ifinfo)
1189 batadv_neigh_ifinfo_free_ref(router_coding_ifinfo);
1190 return res;
1194 * batadv_nc_skb_coding_possible - true if a decoded skb is available at dst.
1195 * @skb: data skb to forward
1196 * @dst: destination mac address of the other skb to code with
1197 * @src: source mac address of skb
1199 * Whenever we network code a packet we have to check whether we received it in
1200 * a network coded form. If so, we may not be able to use it for coding because
1201 * some neighbors may also have received (overheard) the packet in the network
1202 * coded form without being able to decode it. It is hard to know which of the
1203 * neighboring nodes was able to decode the packet, therefore we can only
1204 * re-code the packet if the source of the previous encoded packet is involved.
1205 * Since the source encoded the packet we can be certain it has all necessary
1206 * decode information.
1208 * Returns true if coding of a decoded packet is allowed.
1210 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb,
1211 uint8_t *dst, uint8_t *src)
1213 if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1214 return false;
1215 else
1216 return true;
1220 * batadv_nc_path_search - Find the coding path matching in_nc_node and
1221 * out_nc_node to retrieve a buffered packet that can be used for coding.
1222 * @bat_priv: the bat priv with all the soft interface information
1223 * @in_nc_node: pointer to skb next hop's neighbor nc node
1224 * @out_nc_node: pointer to skb source's neighbor nc node
1225 * @skb: data skb to forward
1226 * @eth_dst: next hop mac address of skb
1228 * Returns true if coding of a decoded skb is allowed.
1230 static struct batadv_nc_packet *
1231 batadv_nc_path_search(struct batadv_priv *bat_priv,
1232 struct batadv_nc_node *in_nc_node,
1233 struct batadv_nc_node *out_nc_node,
1234 struct sk_buff *skb,
1235 uint8_t *eth_dst)
1237 struct batadv_nc_path *nc_path, nc_path_key;
1238 struct batadv_nc_packet *nc_packet_out = NULL;
1239 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1240 struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1241 int idx;
1243 if (!hash)
1244 return NULL;
1246 /* Create almost path key */
1247 batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1248 out_nc_node->addr);
1249 idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1251 /* Check for coding opportunities in this nc_path */
1252 rcu_read_lock();
1253 hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1254 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1255 continue;
1257 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1258 continue;
1260 spin_lock_bh(&nc_path->packet_list_lock);
1261 if (list_empty(&nc_path->packet_list)) {
1262 spin_unlock_bh(&nc_path->packet_list_lock);
1263 continue;
1266 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1267 &nc_path->packet_list, list) {
1268 if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1269 eth_dst,
1270 in_nc_node->addr))
1271 continue;
1273 /* Coding opportunity is found! */
1274 list_del(&nc_packet->list);
1275 nc_packet_out = nc_packet;
1276 break;
1279 spin_unlock_bh(&nc_path->packet_list_lock);
1280 break;
1282 rcu_read_unlock();
1284 return nc_packet_out;
1288 * batadv_nc_skb_src_search - Loops through the list of neighoring nodes of the
1289 * skb's sender (may be equal to the originator).
1290 * @bat_priv: the bat priv with all the soft interface information
1291 * @skb: data skb to forward
1292 * @eth_dst: next hop mac address of skb
1293 * @eth_src: source mac address of skb
1294 * @in_nc_node: pointer to skb next hop's neighbor nc node
1296 * Returns an nc packet if a suitable coding packet was found, NULL otherwise.
1298 static struct batadv_nc_packet *
1299 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1300 struct sk_buff *skb,
1301 uint8_t *eth_dst,
1302 uint8_t *eth_src,
1303 struct batadv_nc_node *in_nc_node)
1305 struct batadv_orig_node *orig_node;
1306 struct batadv_nc_node *out_nc_node;
1307 struct batadv_nc_packet *nc_packet = NULL;
1309 orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1310 if (!orig_node)
1311 return NULL;
1313 rcu_read_lock();
1314 list_for_each_entry_rcu(out_nc_node,
1315 &orig_node->out_coding_list, list) {
1316 /* Check if the skb is decoded and if recoding is possible */
1317 if (!batadv_nc_skb_coding_possible(skb,
1318 out_nc_node->addr, eth_src))
1319 continue;
1321 /* Search for an opportunity in this nc_path */
1322 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1323 out_nc_node, skb, eth_dst);
1324 if (nc_packet)
1325 break;
1327 rcu_read_unlock();
1329 batadv_orig_node_free_ref(orig_node);
1330 return nc_packet;
1334 * batadv_nc_skb_store_before_coding - set the ethernet src and dst of the
1335 * unicast skb before it is stored for use in later decoding
1336 * @bat_priv: the bat priv with all the soft interface information
1337 * @skb: data skb to store
1338 * @eth_dst_new: new destination mac address of skb
1340 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1341 struct sk_buff *skb,
1342 uint8_t *eth_dst_new)
1344 struct ethhdr *ethhdr;
1346 /* Copy skb header to change the mac header */
1347 skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1348 if (!skb)
1349 return;
1351 /* Set the mac header as if we actually sent the packet uncoded */
1352 ethhdr = eth_hdr(skb);
1353 ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1354 ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1356 /* Set data pointer to MAC header to mimic packets from our tx path */
1357 skb_push(skb, ETH_HLEN);
1359 /* Add the packet to the decoding packet pool */
1360 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1362 /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1363 * our ref
1365 kfree_skb(skb);
1369 * batadv_nc_skb_dst_search - Loops through list of neighboring nodes to dst.
1370 * @skb: data skb to forward
1371 * @neigh_node: next hop to forward packet to
1372 * @ethhdr: pointer to the ethernet header inside the skb
1374 * Loops through list of neighboring nodes the next hop has a good connection to
1375 * (receives OGMs with a sufficient quality). We need to find a neighbor of our
1376 * next hop that potentially sent a packet which our next hop also received
1377 * (overheard) and has stored for later decoding.
1379 * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1381 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1382 struct batadv_neigh_node *neigh_node,
1383 struct ethhdr *ethhdr)
1385 struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1386 struct batadv_priv *bat_priv = netdev_priv(netdev);
1387 struct batadv_orig_node *orig_node = neigh_node->orig_node;
1388 struct batadv_nc_node *nc_node;
1389 struct batadv_nc_packet *nc_packet = NULL;
1391 rcu_read_lock();
1392 list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1393 /* Search for coding opportunity with this in_nc_node */
1394 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1395 neigh_node->addr,
1396 ethhdr->h_source, nc_node);
1398 /* Opportunity was found, so stop searching */
1399 if (nc_packet)
1400 break;
1402 rcu_read_unlock();
1404 if (!nc_packet)
1405 return false;
1407 /* Save packets for later decoding */
1408 batadv_nc_skb_store_before_coding(bat_priv, skb,
1409 neigh_node->addr);
1410 batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1411 nc_packet->neigh_node->addr);
1413 /* Code and send packets */
1414 if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1415 neigh_node))
1416 return true;
1418 /* out of mem ? Coding failed - we have to free the buffered packet
1419 * to avoid memleaks. The skb passed as argument will be dealt with
1420 * by the calling function.
1422 batadv_nc_send_packet(nc_packet);
1423 return false;
1427 * batadv_nc_skb_add_to_path - buffer skb for later encoding / decoding
1428 * @skb: skb to add to path
1429 * @nc_path: path to add skb to
1430 * @neigh_node: next hop to forward packet to
1431 * @packet_id: checksum to identify packet
1433 * Returns true if the packet was buffered or false in case of an error.
1435 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1436 struct batadv_nc_path *nc_path,
1437 struct batadv_neigh_node *neigh_node,
1438 __be32 packet_id)
1440 struct batadv_nc_packet *nc_packet;
1442 nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1443 if (!nc_packet)
1444 return false;
1446 /* Initialize nc_packet */
1447 nc_packet->timestamp = jiffies;
1448 nc_packet->packet_id = packet_id;
1449 nc_packet->skb = skb;
1450 nc_packet->neigh_node = neigh_node;
1451 nc_packet->nc_path = nc_path;
1453 /* Add coding packet to list */
1454 spin_lock_bh(&nc_path->packet_list_lock);
1455 list_add_tail(&nc_packet->list, &nc_path->packet_list);
1456 spin_unlock_bh(&nc_path->packet_list_lock);
1458 return true;
1462 * batadv_nc_skb_forward - try to code a packet or add it to the coding packet
1463 * buffer
1464 * @skb: data skb to forward
1465 * @neigh_node: next hop to forward packet to
1467 * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1469 bool batadv_nc_skb_forward(struct sk_buff *skb,
1470 struct batadv_neigh_node *neigh_node)
1472 const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1473 struct batadv_priv *bat_priv = netdev_priv(netdev);
1474 struct batadv_unicast_packet *packet;
1475 struct batadv_nc_path *nc_path;
1476 struct ethhdr *ethhdr = eth_hdr(skb);
1477 __be32 packet_id;
1478 u8 *payload;
1480 /* Check if network coding is enabled */
1481 if (!atomic_read(&bat_priv->network_coding))
1482 goto out;
1484 /* We only handle unicast packets */
1485 payload = skb_network_header(skb);
1486 packet = (struct batadv_unicast_packet *)payload;
1487 if (packet->packet_type != BATADV_UNICAST)
1488 goto out;
1490 /* Try to find a coding opportunity and send the skb if one is found */
1491 if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1492 return true;
1494 /* Find or create a nc_path for this src-dst pair */
1495 nc_path = batadv_nc_get_path(bat_priv,
1496 bat_priv->nc.coding_hash,
1497 ethhdr->h_source,
1498 neigh_node->addr);
1500 if (!nc_path)
1501 goto out;
1503 /* Add skb to nc_path */
1504 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1505 if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1506 goto free_nc_path;
1508 /* Packet is consumed */
1509 return true;
1511 free_nc_path:
1512 batadv_nc_path_free_ref(nc_path);
1513 out:
1514 /* Packet is not consumed */
1515 return false;
1519 * batadv_nc_skb_store_for_decoding - save a clone of the skb which can be used
1520 * when decoding coded packets
1521 * @bat_priv: the bat priv with all the soft interface information
1522 * @skb: data skb to store
1524 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1525 struct sk_buff *skb)
1527 struct batadv_unicast_packet *packet;
1528 struct batadv_nc_path *nc_path;
1529 struct ethhdr *ethhdr = eth_hdr(skb);
1530 __be32 packet_id;
1531 u8 *payload;
1533 /* Check if network coding is enabled */
1534 if (!atomic_read(&bat_priv->network_coding))
1535 goto out;
1537 /* Check for supported packet type */
1538 payload = skb_network_header(skb);
1539 packet = (struct batadv_unicast_packet *)payload;
1540 if (packet->packet_type != BATADV_UNICAST)
1541 goto out;
1543 /* Find existing nc_path or create a new */
1544 nc_path = batadv_nc_get_path(bat_priv,
1545 bat_priv->nc.decoding_hash,
1546 ethhdr->h_source,
1547 ethhdr->h_dest);
1549 if (!nc_path)
1550 goto out;
1552 /* Clone skb and adjust skb->data to point at batman header */
1553 skb = skb_clone(skb, GFP_ATOMIC);
1554 if (unlikely(!skb))
1555 goto free_nc_path;
1557 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1558 goto free_skb;
1560 if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1561 goto free_skb;
1563 /* Add skb to nc_path */
1564 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1565 if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1566 goto free_skb;
1568 batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1569 return;
1571 free_skb:
1572 kfree_skb(skb);
1573 free_nc_path:
1574 batadv_nc_path_free_ref(nc_path);
1575 out:
1576 return;
1580 * batadv_nc_skb_store_sniffed_unicast - check if a received unicast packet
1581 * should be saved in the decoding buffer and, if so, store it there
1582 * @bat_priv: the bat priv with all the soft interface information
1583 * @skb: unicast skb to store
1585 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1586 struct sk_buff *skb)
1588 struct ethhdr *ethhdr = eth_hdr(skb);
1590 if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1591 return;
1593 /* Set data pointer to MAC header to mimic packets from our tx path */
1594 skb_push(skb, ETH_HLEN);
1596 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1600 * batadv_nc_skb_decode_packet - decode given skb using the decode data stored
1601 * in nc_packet
1602 * @bat_priv: the bat priv with all the soft interface information
1603 * @skb: unicast skb to decode
1604 * @nc_packet: decode data needed to decode the skb
1606 * Returns pointer to decoded unicast packet if the packet was decoded or NULL
1607 * in case of an error.
1609 static struct batadv_unicast_packet *
1610 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1611 struct batadv_nc_packet *nc_packet)
1613 const int h_size = sizeof(struct batadv_unicast_packet);
1614 const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1615 struct batadv_unicast_packet *unicast_packet;
1616 struct batadv_coded_packet coded_packet_tmp;
1617 struct ethhdr *ethhdr, ethhdr_tmp;
1618 uint8_t *orig_dest, ttl, ttvn;
1619 unsigned int coding_len;
1620 int err;
1622 /* Save headers temporarily */
1623 memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1624 memcpy(&ethhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1626 if (skb_cow(skb, 0) < 0)
1627 return NULL;
1629 if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1630 return NULL;
1632 /* Data points to batman header, so set mac header 14 bytes before
1633 * and network to data
1635 skb_set_mac_header(skb, -ETH_HLEN);
1636 skb_reset_network_header(skb);
1638 /* Reconstruct original mac header */
1639 ethhdr = eth_hdr(skb);
1640 *ethhdr = ethhdr_tmp;
1642 /* Select the correct unicast header information based on the location
1643 * of our mac address in the coded_packet header
1645 if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1646 /* If we are the second destination the packet was overheard,
1647 * so the Ethernet address must be copied to h_dest and
1648 * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1650 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1651 skb->pkt_type = PACKET_HOST;
1653 orig_dest = coded_packet_tmp.second_orig_dest;
1654 ttl = coded_packet_tmp.second_ttl;
1655 ttvn = coded_packet_tmp.second_ttvn;
1656 } else {
1657 orig_dest = coded_packet_tmp.first_orig_dest;
1658 ttl = coded_packet_tmp.ttl;
1659 ttvn = coded_packet_tmp.first_ttvn;
1662 coding_len = ntohs(coded_packet_tmp.coded_len);
1664 if (coding_len > skb->len)
1665 return NULL;
1667 /* Here the magic is reversed:
1668 * extract the missing packet from the received coded packet
1670 batadv_nc_memxor(skb->data + h_size,
1671 nc_packet->skb->data + h_size,
1672 coding_len);
1674 /* Resize decoded skb if decoded with larger packet */
1675 if (nc_packet->skb->len > coding_len + h_size) {
1676 err = pskb_trim_rcsum(skb, coding_len + h_size);
1677 if (err)
1678 return NULL;
1681 /* Create decoded unicast packet */
1682 unicast_packet = (struct batadv_unicast_packet *)skb->data;
1683 unicast_packet->packet_type = BATADV_UNICAST;
1684 unicast_packet->version = BATADV_COMPAT_VERSION;
1685 unicast_packet->ttl = ttl;
1686 ether_addr_copy(unicast_packet->dest, orig_dest);
1687 unicast_packet->ttvn = ttvn;
1689 batadv_nc_packet_free(nc_packet);
1690 return unicast_packet;
1694 * batadv_nc_find_decoding_packet - search through buffered decoding data to
1695 * find the data needed to decode the coded packet
1696 * @bat_priv: the bat priv with all the soft interface information
1697 * @ethhdr: pointer to the ethernet header inside the coded packet
1698 * @coded: coded packet we try to find decode data for
1700 * Returns pointer to nc packet if the needed data was found or NULL otherwise.
1702 static struct batadv_nc_packet *
1703 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1704 struct ethhdr *ethhdr,
1705 struct batadv_coded_packet *coded)
1707 struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1708 struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1709 struct batadv_nc_path *nc_path, nc_path_key;
1710 uint8_t *dest, *source;
1711 __be32 packet_id;
1712 int index;
1714 if (!hash)
1715 return NULL;
1717 /* Select the correct packet id based on the location of our mac-addr */
1718 dest = ethhdr->h_source;
1719 if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1720 source = coded->second_source;
1721 packet_id = coded->second_crc;
1722 } else {
1723 source = coded->first_source;
1724 packet_id = coded->first_crc;
1727 batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1728 index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1730 /* Search for matching coding path */
1731 rcu_read_lock();
1732 hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1733 /* Find matching nc_packet */
1734 spin_lock_bh(&nc_path->packet_list_lock);
1735 list_for_each_entry(tmp_nc_packet,
1736 &nc_path->packet_list, list) {
1737 if (packet_id == tmp_nc_packet->packet_id) {
1738 list_del(&tmp_nc_packet->list);
1740 nc_packet = tmp_nc_packet;
1741 break;
1744 spin_unlock_bh(&nc_path->packet_list_lock);
1746 if (nc_packet)
1747 break;
1749 rcu_read_unlock();
1751 if (!nc_packet)
1752 batadv_dbg(BATADV_DBG_NC, bat_priv,
1753 "No decoding packet found for %u\n", packet_id);
1755 return nc_packet;
1759 * batadv_nc_recv_coded_packet - try to decode coded packet and enqueue the
1760 * resulting unicast packet
1761 * @skb: incoming coded packet
1762 * @recv_if: pointer to interface this packet was received on
1764 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1765 struct batadv_hard_iface *recv_if)
1767 struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1768 struct batadv_unicast_packet *unicast_packet;
1769 struct batadv_coded_packet *coded_packet;
1770 struct batadv_nc_packet *nc_packet;
1771 struct ethhdr *ethhdr;
1772 int hdr_size = sizeof(*coded_packet);
1774 /* Check if network coding is enabled */
1775 if (!atomic_read(&bat_priv->network_coding))
1776 return NET_RX_DROP;
1778 /* Make sure we can access (and remove) header */
1779 if (unlikely(!pskb_may_pull(skb, hdr_size)))
1780 return NET_RX_DROP;
1782 coded_packet = (struct batadv_coded_packet *)skb->data;
1783 ethhdr = eth_hdr(skb);
1785 /* Verify frame is destined for us */
1786 if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1787 !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1788 return NET_RX_DROP;
1790 /* Update stat counter */
1791 if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1792 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1794 nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1795 coded_packet);
1796 if (!nc_packet) {
1797 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1798 return NET_RX_DROP;
1801 /* Make skb's linear, because decoding accesses the entire buffer */
1802 if (skb_linearize(skb) < 0)
1803 goto free_nc_packet;
1805 if (skb_linearize(nc_packet->skb) < 0)
1806 goto free_nc_packet;
1808 /* Decode the packet */
1809 unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1810 if (!unicast_packet) {
1811 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1812 goto free_nc_packet;
1815 /* Mark packet as decoded to do correct recoding when forwarding */
1816 BATADV_SKB_CB(skb)->decoded = true;
1817 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1818 batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1819 skb->len + ETH_HLEN);
1820 return batadv_recv_unicast_packet(skb, recv_if);
1822 free_nc_packet:
1823 batadv_nc_packet_free(nc_packet);
1824 return NET_RX_DROP;
1828 * batadv_nc_mesh_free - clean up network coding memory
1829 * @bat_priv: the bat priv with all the soft interface information
1831 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1833 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1834 batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1835 cancel_delayed_work_sync(&bat_priv->nc.work);
1837 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1838 batadv_hash_destroy(bat_priv->nc.coding_hash);
1839 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1840 batadv_hash_destroy(bat_priv->nc.decoding_hash);
1844 * batadv_nc_nodes_seq_print_text - print the nc node information
1845 * @seq: seq file to print on
1846 * @offset: not used
1848 int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
1850 struct net_device *net_dev = (struct net_device *)seq->private;
1851 struct batadv_priv *bat_priv = netdev_priv(net_dev);
1852 struct batadv_hashtable *hash = bat_priv->orig_hash;
1853 struct batadv_hard_iface *primary_if;
1854 struct hlist_head *head;
1855 struct batadv_orig_node *orig_node;
1856 struct batadv_nc_node *nc_node;
1857 int i;
1859 primary_if = batadv_seq_print_text_primary_if_get(seq);
1860 if (!primary_if)
1861 goto out;
1863 /* Traverse list of originators */
1864 for (i = 0; i < hash->size; i++) {
1865 head = &hash->table[i];
1867 /* For each orig_node in this bin */
1868 rcu_read_lock();
1869 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1870 /* no need to print the orig node if it does not have
1871 * network coding neighbors
1873 if (list_empty(&orig_node->in_coding_list) &&
1874 list_empty(&orig_node->out_coding_list))
1875 continue;
1877 seq_printf(seq, "Node: %pM\n", orig_node->orig);
1879 seq_puts(seq, " Ingoing: ");
1880 /* For each in_nc_node to this orig_node */
1881 list_for_each_entry_rcu(nc_node,
1882 &orig_node->in_coding_list,
1883 list)
1884 seq_printf(seq, "%pM ",
1885 nc_node->addr);
1886 seq_puts(seq, "\n");
1888 seq_puts(seq, " Outgoing: ");
1889 /* For out_nc_node to this orig_node */
1890 list_for_each_entry_rcu(nc_node,
1891 &orig_node->out_coding_list,
1892 list)
1893 seq_printf(seq, "%pM ",
1894 nc_node->addr);
1895 seq_puts(seq, "\n\n");
1897 rcu_read_unlock();
1900 out:
1901 if (primary_if)
1902 batadv_hardif_free_ref(primary_if);
1903 return 0;
1907 * batadv_nc_init_debugfs - create nc folder and related files in debugfs
1908 * @bat_priv: the bat priv with all the soft interface information
1910 int batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
1912 struct dentry *nc_dir, *file;
1914 nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
1915 if (!nc_dir)
1916 goto out;
1918 file = debugfs_create_u8("min_tq", S_IRUGO | S_IWUSR, nc_dir,
1919 &bat_priv->nc.min_tq);
1920 if (!file)
1921 goto out;
1923 file = debugfs_create_u32("max_fwd_delay", S_IRUGO | S_IWUSR, nc_dir,
1924 &bat_priv->nc.max_fwd_delay);
1925 if (!file)
1926 goto out;
1928 file = debugfs_create_u32("max_buffer_time", S_IRUGO | S_IWUSR, nc_dir,
1929 &bat_priv->nc.max_buffer_time);
1930 if (!file)
1931 goto out;
1933 return 0;
1935 out:
1936 return -ENOMEM;