1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2012-2018 B.A.T.M.A.N. contributors:
4 * Martin Hundebøll, Jeppe Ledet-Pedersen
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of version 2 of the GNU General Public
8 * License as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, see <http://www.gnu.org/licenses/>.
19 #include "network-coding.h"
22 #include <linux/atomic.h>
23 #include <linux/bitops.h>
24 #include <linux/byteorder/generic.h>
25 #include <linux/compiler.h>
26 #include <linux/debugfs.h>
27 #include <linux/errno.h>
28 #include <linux/etherdevice.h>
29 #include <linux/gfp.h>
30 #include <linux/if_ether.h>
31 #include <linux/if_packet.h>
32 #include <linux/init.h>
33 #include <linux/jhash.h>
34 #include <linux/jiffies.h>
35 #include <linux/kernel.h>
36 #include <linux/kref.h>
37 #include <linux/list.h>
38 #include <linux/lockdep.h>
39 #include <linux/net.h>
40 #include <linux/netdevice.h>
41 #include <linux/printk.h>
42 #include <linux/random.h>
43 #include <linux/rculist.h>
44 #include <linux/rcupdate.h>
45 #include <linux/seq_file.h>
46 #include <linux/skbuff.h>
47 #include <linux/slab.h>
48 #include <linux/spinlock.h>
49 #include <linux/stddef.h>
50 #include <linux/string.h>
51 #include <linux/workqueue.h>
52 #include <uapi/linux/batadv_packet.h>
54 #include "hard-interface.h"
57 #include "originator.h"
62 static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
63 static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
65 static void batadv_nc_worker(struct work_struct *work);
66 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
67 struct batadv_hard_iface *recv_if);
70 * batadv_nc_init() - one-time initialization for network coding
72 * Return: 0 on success or negative error number in case of failure
74 int __init batadv_nc_init(void)
78 /* Register our packet type */
79 ret = batadv_recv_handler_register(BATADV_CODED,
80 batadv_nc_recv_coded_packet);
86 * batadv_nc_start_timer() - initialise the nc periodic worker
87 * @bat_priv: the bat priv with all the soft interface information
89 static void batadv_nc_start_timer(struct batadv_priv *bat_priv)
91 queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work,
92 msecs_to_jiffies(10));
96 * batadv_nc_tvlv_container_update() - update the network coding tvlv container
97 * after network coding setting change
98 * @bat_priv: the bat priv with all the soft interface information
100 static void batadv_nc_tvlv_container_update(struct batadv_priv *bat_priv)
104 nc_mode = atomic_read(&bat_priv->network_coding);
108 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
111 batadv_tvlv_container_register(bat_priv, BATADV_TVLV_NC, 1,
118 * batadv_nc_status_update() - update the network coding tvlv container after
119 * network coding setting change
120 * @net_dev: the soft interface net device
122 void batadv_nc_status_update(struct net_device *net_dev)
124 struct batadv_priv *bat_priv = netdev_priv(net_dev);
126 batadv_nc_tvlv_container_update(bat_priv);
130 * batadv_nc_tvlv_ogm_handler_v1() - process incoming nc tvlv container
131 * @bat_priv: the bat priv with all the soft interface information
132 * @orig: the orig_node of the ogm
133 * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
134 * @tvlv_value: tvlv buffer containing the gateway data
135 * @tvlv_value_len: tvlv buffer length
137 static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
138 struct batadv_orig_node *orig,
140 void *tvlv_value, u16 tvlv_value_len)
142 if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
143 clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
145 set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
149 * batadv_nc_mesh_init() - initialise coding hash table and start house keeping
150 * @bat_priv: the bat priv with all the soft interface information
152 * Return: 0 on success or negative error number in case of failure
154 int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
156 bat_priv->nc.timestamp_fwd_flush = jiffies;
157 bat_priv->nc.timestamp_sniffed_purge = jiffies;
159 if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
162 bat_priv->nc.coding_hash = batadv_hash_new(128);
163 if (!bat_priv->nc.coding_hash)
166 batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
167 &batadv_nc_coding_hash_lock_class_key);
169 bat_priv->nc.decoding_hash = batadv_hash_new(128);
170 if (!bat_priv->nc.decoding_hash) {
171 batadv_hash_destroy(bat_priv->nc.coding_hash);
175 batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
176 &batadv_nc_decoding_hash_lock_class_key);
178 INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
179 batadv_nc_start_timer(bat_priv);
181 batadv_tvlv_handler_register(bat_priv, batadv_nc_tvlv_ogm_handler_v1,
182 NULL, BATADV_TVLV_NC, 1,
183 BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
184 batadv_nc_tvlv_container_update(bat_priv);
192 * batadv_nc_init_bat_priv() - initialise the nc specific bat_priv variables
193 * @bat_priv: the bat priv with all the soft interface information
195 void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
197 atomic_set(&bat_priv->network_coding, 0);
198 bat_priv->nc.min_tq = 200;
199 bat_priv->nc.max_fwd_delay = 10;
200 bat_priv->nc.max_buffer_time = 200;
204 * batadv_nc_init_orig() - initialise the nc fields of an orig_node
205 * @orig_node: the orig_node which is going to be initialised
207 void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
209 INIT_LIST_HEAD(&orig_node->in_coding_list);
210 INIT_LIST_HEAD(&orig_node->out_coding_list);
211 spin_lock_init(&orig_node->in_coding_list_lock);
212 spin_lock_init(&orig_node->out_coding_list_lock);
216 * batadv_nc_node_release() - release nc_node from lists and queue for free
217 * after rcu grace period
218 * @ref: kref pointer of the nc_node
220 static void batadv_nc_node_release(struct kref *ref)
222 struct batadv_nc_node *nc_node;
224 nc_node = container_of(ref, struct batadv_nc_node, refcount);
226 batadv_orig_node_put(nc_node->orig_node);
227 kfree_rcu(nc_node, rcu);
231 * batadv_nc_node_put() - decrement the nc_node refcounter and possibly
233 * @nc_node: nc_node to be free'd
235 static void batadv_nc_node_put(struct batadv_nc_node *nc_node)
237 kref_put(&nc_node->refcount, batadv_nc_node_release);
241 * batadv_nc_path_release() - release nc_path from lists and queue for free
242 * after rcu grace period
243 * @ref: kref pointer of the nc_path
245 static void batadv_nc_path_release(struct kref *ref)
247 struct batadv_nc_path *nc_path;
249 nc_path = container_of(ref, struct batadv_nc_path, refcount);
251 kfree_rcu(nc_path, rcu);
255 * batadv_nc_path_put() - decrement the nc_path refcounter and possibly
257 * @nc_path: nc_path to be free'd
259 static void batadv_nc_path_put(struct batadv_nc_path *nc_path)
261 kref_put(&nc_path->refcount, batadv_nc_path_release);
265 * batadv_nc_packet_free() - frees nc packet
266 * @nc_packet: the nc packet to free
267 * @dropped: whether the packet is freed because is is dropped
269 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet,
273 kfree_skb(nc_packet->skb);
275 consume_skb(nc_packet->skb);
277 batadv_nc_path_put(nc_packet->nc_path);
282 * batadv_nc_to_purge_nc_node() - checks whether an nc node has to be purged
283 * @bat_priv: the bat priv with all the soft interface information
284 * @nc_node: the nc node to check
286 * Return: true if the entry has to be purged now, false otherwise
288 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
289 struct batadv_nc_node *nc_node)
291 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
294 return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
298 * batadv_nc_to_purge_nc_path_coding() - checks whether an nc path has timed out
299 * @bat_priv: the bat priv with all the soft interface information
300 * @nc_path: the nc path to check
302 * Return: true if the entry has to be purged now, false otherwise
304 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
305 struct batadv_nc_path *nc_path)
307 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
310 /* purge the path when no packets has been added for 10 times the
313 return batadv_has_timed_out(nc_path->last_valid,
314 bat_priv->nc.max_fwd_delay * 10);
318 * batadv_nc_to_purge_nc_path_decoding() - checks whether an nc path has timed
320 * @bat_priv: the bat priv with all the soft interface information
321 * @nc_path: the nc path to check
323 * Return: true if the entry has to be purged now, false otherwise
325 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
326 struct batadv_nc_path *nc_path)
328 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
331 /* purge the path when no packets has been added for 10 times the
334 return batadv_has_timed_out(nc_path->last_valid,
335 bat_priv->nc.max_buffer_time * 10);
339 * batadv_nc_purge_orig_nc_nodes() - go through list of nc nodes and purge stale
341 * @bat_priv: the bat priv with all the soft interface information
342 * @list: list of nc nodes
343 * @lock: nc node list lock
344 * @to_purge: function in charge to decide whether an entry has to be purged or
345 * not. This function takes the nc node as argument and has to return
346 * a boolean value: true if the entry has to be deleted, false
350 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
351 struct list_head *list,
353 bool (*to_purge)(struct batadv_priv *,
354 struct batadv_nc_node *))
356 struct batadv_nc_node *nc_node, *nc_node_tmp;
358 /* For each nc_node in list */
360 list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
361 /* if an helper function has been passed as parameter,
362 * ask it if the entry has to be purged or not
364 if (to_purge && !to_purge(bat_priv, nc_node))
367 batadv_dbg(BATADV_DBG_NC, bat_priv,
368 "Removing nc_node %pM -> %pM\n",
369 nc_node->addr, nc_node->orig_node->orig);
370 list_del_rcu(&nc_node->list);
371 batadv_nc_node_put(nc_node);
373 spin_unlock_bh(lock);
377 * batadv_nc_purge_orig() - purges all nc node data attached of the given
379 * @bat_priv: the bat priv with all the soft interface information
380 * @orig_node: orig_node with the nc node entries to be purged
381 * @to_purge: function in charge to decide whether an entry has to be purged or
382 * not. This function takes the nc node as argument and has to return
383 * a boolean value: true is the entry has to be deleted, false
386 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
387 struct batadv_orig_node *orig_node,
388 bool (*to_purge)(struct batadv_priv *,
389 struct batadv_nc_node *))
391 /* Check ingoing nc_node's of this orig_node */
392 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
393 &orig_node->in_coding_list_lock,
396 /* Check outgoing nc_node's of this orig_node */
397 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
398 &orig_node->out_coding_list_lock,
403 * batadv_nc_purge_orig_hash() - traverse entire originator hash to check if
404 * they have timed out nc nodes
405 * @bat_priv: the bat priv with all the soft interface information
407 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
409 struct batadv_hashtable *hash = bat_priv->orig_hash;
410 struct hlist_head *head;
411 struct batadv_orig_node *orig_node;
417 /* For each orig_node */
418 for (i = 0; i < hash->size; i++) {
419 head = &hash->table[i];
422 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
423 batadv_nc_purge_orig(bat_priv, orig_node,
424 batadv_nc_to_purge_nc_node);
430 * batadv_nc_purge_paths() - traverse all nc paths part of the hash and remove
432 * @bat_priv: the bat priv with all the soft interface information
433 * @hash: hash table containing the nc paths to check
434 * @to_purge: function in charge to decide whether an entry has to be purged or
435 * not. This function takes the nc node as argument and has to return
436 * a boolean value: true is the entry has to be deleted, false
439 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
440 struct batadv_hashtable *hash,
441 bool (*to_purge)(struct batadv_priv *,
442 struct batadv_nc_path *))
444 struct hlist_head *head;
445 struct hlist_node *node_tmp;
446 struct batadv_nc_path *nc_path;
447 spinlock_t *lock; /* Protects lists in hash */
450 for (i = 0; i < hash->size; i++) {
451 head = &hash->table[i];
452 lock = &hash->list_locks[i];
454 /* For each nc_path in this bin */
456 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
457 /* if an helper function has been passed as parameter,
458 * ask it if the entry has to be purged or not
460 if (to_purge && !to_purge(bat_priv, nc_path))
463 /* purging an non-empty nc_path should never happen, but
464 * is observed under high CPU load. Delay the purging
465 * until next iteration to allow the packet_list to be
468 if (!unlikely(list_empty(&nc_path->packet_list))) {
469 net_ratelimited_function(printk,
471 "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
477 /* nc_path is unused, so remove it */
478 batadv_dbg(BATADV_DBG_NC, bat_priv,
479 "Remove nc_path %pM -> %pM\n",
480 nc_path->prev_hop, nc_path->next_hop);
481 hlist_del_rcu(&nc_path->hash_entry);
482 batadv_nc_path_put(nc_path);
484 spin_unlock_bh(lock);
489 * batadv_nc_hash_key_gen() - computes the nc_path hash key
490 * @key: buffer to hold the final hash key
491 * @src: source ethernet mac address going into the hash key
492 * @dst: destination ethernet mac address going into the hash key
494 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
497 memcpy(key->prev_hop, src, sizeof(key->prev_hop));
498 memcpy(key->next_hop, dst, sizeof(key->next_hop));
502 * batadv_nc_hash_choose() - compute the hash value for an nc path
503 * @data: data to hash
504 * @size: size of the hash table
506 * Return: the selected index in the hash table for the given data.
508 static u32 batadv_nc_hash_choose(const void *data, u32 size)
510 const struct batadv_nc_path *nc_path = data;
513 hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
514 hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
520 * batadv_nc_hash_compare() - comparing function used in the network coding hash
522 * @node: node in the local table
523 * @data2: second object to compare the node to
525 * Return: true if the two entry are the same, false otherwise
527 static bool batadv_nc_hash_compare(const struct hlist_node *node,
530 const struct batadv_nc_path *nc_path1, *nc_path2;
532 nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
535 /* Return 1 if the two keys are identical */
536 if (!batadv_compare_eth(nc_path1->prev_hop, nc_path2->prev_hop))
539 if (!batadv_compare_eth(nc_path1->next_hop, nc_path2->next_hop))
546 * batadv_nc_hash_find() - search for an existing nc path and return it
547 * @hash: hash table containing the nc path
550 * Return: the nc_path if found, NULL otherwise.
552 static struct batadv_nc_path *
553 batadv_nc_hash_find(struct batadv_hashtable *hash,
556 struct hlist_head *head;
557 struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
563 index = batadv_nc_hash_choose(data, hash->size);
564 head = &hash->table[index];
567 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
568 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
571 if (!kref_get_unless_zero(&nc_path->refcount))
574 nc_path_tmp = nc_path;
583 * batadv_nc_send_packet() - send non-coded packet and free nc_packet struct
584 * @nc_packet: the nc packet to send
586 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
588 batadv_send_unicast_skb(nc_packet->skb, nc_packet->neigh_node);
589 nc_packet->skb = NULL;
590 batadv_nc_packet_free(nc_packet, false);
594 * batadv_nc_sniffed_purge() - Checks timestamp of given sniffed nc_packet.
595 * @bat_priv: the bat priv with all the soft interface information
596 * @nc_path: the nc path the packet belongs to
597 * @nc_packet: the nc packet to be checked
599 * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
600 * timeout. If so, the packet is no longer kept and the entry deleted from the
601 * queue. Has to be called with the appropriate locks.
603 * Return: false as soon as the entry in the fifo queue has not been timed out
604 * yet and true otherwise.
606 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
607 struct batadv_nc_path *nc_path,
608 struct batadv_nc_packet *nc_packet)
610 unsigned long timeout = bat_priv->nc.max_buffer_time;
613 lockdep_assert_held(&nc_path->packet_list_lock);
615 /* Packets are added to tail, so the remaining packets did not time
616 * out and we can stop processing the current queue
618 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
619 !batadv_has_timed_out(nc_packet->timestamp, timeout))
622 /* purge nc packet */
623 list_del(&nc_packet->list);
624 batadv_nc_packet_free(nc_packet, true);
633 * batadv_nc_fwd_flush() - Checks the timestamp of the given nc packet.
634 * @bat_priv: the bat priv with all the soft interface information
635 * @nc_path: the nc path the packet belongs to
636 * @nc_packet: the nc packet to be checked
638 * Checks whether the given nc packet has hit its forward timeout. If so, the
639 * packet is no longer delayed, immediately sent and the entry deleted from the
640 * queue. Has to be called with the appropriate locks.
642 * Return: false as soon as the entry in the fifo queue has not been timed out
643 * yet and true otherwise.
645 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
646 struct batadv_nc_path *nc_path,
647 struct batadv_nc_packet *nc_packet)
649 unsigned long timeout = bat_priv->nc.max_fwd_delay;
651 lockdep_assert_held(&nc_path->packet_list_lock);
653 /* Packets are added to tail, so the remaining packets did not time
654 * out and we can stop processing the current queue
656 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
657 !batadv_has_timed_out(nc_packet->timestamp, timeout))
661 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
662 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
663 nc_packet->skb->len + ETH_HLEN);
664 list_del(&nc_packet->list);
665 batadv_nc_send_packet(nc_packet);
671 * batadv_nc_process_nc_paths() - traverse given nc packet pool and free timed
673 * @bat_priv: the bat priv with all the soft interface information
674 * @hash: to be processed hash table
675 * @process_fn: Function called to process given nc packet. Should return true
676 * to encourage this function to proceed with the next packet.
677 * Otherwise the rest of the current queue is skipped.
680 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
681 struct batadv_hashtable *hash,
682 bool (*process_fn)(struct batadv_priv *,
683 struct batadv_nc_path *,
684 struct batadv_nc_packet *))
686 struct hlist_head *head;
687 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
688 struct batadv_nc_path *nc_path;
695 /* Loop hash table bins */
696 for (i = 0; i < hash->size; i++) {
697 head = &hash->table[i];
699 /* Loop coding paths */
701 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
703 spin_lock_bh(&nc_path->packet_list_lock);
704 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
705 &nc_path->packet_list, list) {
706 ret = process_fn(bat_priv, nc_path, nc_packet);
710 spin_unlock_bh(&nc_path->packet_list_lock);
717 * batadv_nc_worker() - periodic task for house keeping related to network
719 * @work: kernel work struct
721 static void batadv_nc_worker(struct work_struct *work)
723 struct delayed_work *delayed_work;
724 struct batadv_priv_nc *priv_nc;
725 struct batadv_priv *bat_priv;
726 unsigned long timeout;
728 delayed_work = to_delayed_work(work);
729 priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
730 bat_priv = container_of(priv_nc, struct batadv_priv, nc);
732 batadv_nc_purge_orig_hash(bat_priv);
733 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
734 batadv_nc_to_purge_nc_path_coding);
735 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
736 batadv_nc_to_purge_nc_path_decoding);
738 timeout = bat_priv->nc.max_fwd_delay;
740 if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
741 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
742 batadv_nc_fwd_flush);
743 bat_priv->nc.timestamp_fwd_flush = jiffies;
746 if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
747 bat_priv->nc.max_buffer_time)) {
748 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
749 batadv_nc_sniffed_purge);
750 bat_priv->nc.timestamp_sniffed_purge = jiffies;
753 /* Schedule a new check */
754 batadv_nc_start_timer(bat_priv);
758 * batadv_can_nc_with_orig() - checks whether the given orig node is suitable
760 * @bat_priv: the bat priv with all the soft interface information
761 * @orig_node: neighboring orig node which may be used as nc candidate
762 * @ogm_packet: incoming ogm packet also used for the checks
765 * 1) The OGM must have the most recent sequence number.
766 * 2) The TTL must be decremented by one and only one.
767 * 3) The OGM must be received from the first hop from orig_node.
768 * 4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
770 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
771 struct batadv_orig_node *orig_node,
772 struct batadv_ogm_packet *ogm_packet)
774 struct batadv_orig_ifinfo *orig_ifinfo;
778 orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
782 last_ttl = orig_ifinfo->last_ttl;
783 last_real_seqno = orig_ifinfo->last_real_seqno;
784 batadv_orig_ifinfo_put(orig_ifinfo);
786 if (last_real_seqno != ntohl(ogm_packet->seqno))
788 if (last_ttl != ogm_packet->ttl + 1)
790 if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
792 if (ogm_packet->tq < bat_priv->nc.min_tq)
799 * batadv_nc_find_nc_node() - search for an existing nc node and return it
800 * @orig_node: orig node originating the ogm packet
801 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
802 * (can be equal to orig_node)
803 * @in_coding: traverse incoming or outgoing network coding list
805 * Return: the nc_node if found, NULL otherwise.
807 static struct batadv_nc_node *
808 batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
809 struct batadv_orig_node *orig_neigh_node,
812 struct batadv_nc_node *nc_node, *nc_node_out = NULL;
813 struct list_head *list;
816 list = &orig_neigh_node->in_coding_list;
818 list = &orig_neigh_node->out_coding_list;
820 /* Traverse list of nc_nodes to orig_node */
822 list_for_each_entry_rcu(nc_node, list, list) {
823 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
826 if (!kref_get_unless_zero(&nc_node->refcount))
830 nc_node_out = nc_node;
839 * batadv_nc_get_nc_node() - retrieves an nc node or creates the entry if it was
841 * @bat_priv: the bat priv with all the soft interface information
842 * @orig_node: orig node originating the ogm packet
843 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
844 * (can be equal to orig_node)
845 * @in_coding: traverse incoming or outgoing network coding list
847 * Return: the nc_node if found or created, NULL in case of an error.
849 static struct batadv_nc_node *
850 batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
851 struct batadv_orig_node *orig_node,
852 struct batadv_orig_node *orig_neigh_node,
855 struct batadv_nc_node *nc_node;
856 spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
857 struct list_head *list;
859 /* Select ingoing or outgoing coding node */
861 lock = &orig_neigh_node->in_coding_list_lock;
862 list = &orig_neigh_node->in_coding_list;
864 lock = &orig_neigh_node->out_coding_list_lock;
865 list = &orig_neigh_node->out_coding_list;
870 /* Check if nc_node is already added */
871 nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
877 nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
881 /* Initialize nc_node */
882 INIT_LIST_HEAD(&nc_node->list);
883 kref_init(&nc_node->refcount);
884 ether_addr_copy(nc_node->addr, orig_node->orig);
885 kref_get(&orig_neigh_node->refcount);
886 nc_node->orig_node = orig_neigh_node;
888 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
889 nc_node->addr, nc_node->orig_node->orig);
891 /* Add nc_node to orig_node */
892 kref_get(&nc_node->refcount);
893 list_add_tail_rcu(&nc_node->list, list);
896 spin_unlock_bh(lock);
902 * batadv_nc_update_nc_node() - updates stored incoming and outgoing nc node
903 * structs (best called on incoming OGMs)
904 * @bat_priv: the bat priv with all the soft interface information
905 * @orig_node: orig node originating the ogm packet
906 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
907 * (can be equal to orig_node)
908 * @ogm_packet: incoming ogm packet
909 * @is_single_hop_neigh: orig_node is a single hop neighbor
911 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
912 struct batadv_orig_node *orig_node,
913 struct batadv_orig_node *orig_neigh_node,
914 struct batadv_ogm_packet *ogm_packet,
915 int is_single_hop_neigh)
917 struct batadv_nc_node *in_nc_node = NULL;
918 struct batadv_nc_node *out_nc_node = NULL;
920 /* Check if network coding is enabled */
921 if (!atomic_read(&bat_priv->network_coding))
924 /* check if orig node is network coding enabled */
925 if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
928 /* accept ogms from 'good' neighbors and single hop neighbors */
929 if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
930 !is_single_hop_neigh)
933 /* Add orig_node as in_nc_node on hop */
934 in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
935 orig_neigh_node, true);
939 in_nc_node->last_seen = jiffies;
941 /* Add hop as out_nc_node on orig_node */
942 out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
947 out_nc_node->last_seen = jiffies;
951 batadv_nc_node_put(in_nc_node);
953 batadv_nc_node_put(out_nc_node);
957 * batadv_nc_get_path() - get existing nc_path or allocate a new one
958 * @bat_priv: the bat priv with all the soft interface information
959 * @hash: hash table containing the nc path
960 * @src: ethernet source address - first half of the nc path search key
961 * @dst: ethernet destination address - second half of the nc path search key
963 * Return: pointer to nc_path if the path was found or created, returns NULL
966 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
967 struct batadv_hashtable *hash,
972 struct batadv_nc_path *nc_path, nc_path_key;
974 batadv_nc_hash_key_gen(&nc_path_key, src, dst);
976 /* Search for existing nc_path */
977 nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
980 /* Set timestamp to delay removal of nc_path */
981 nc_path->last_valid = jiffies;
985 /* No existing nc_path was found; create a new */
986 nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
991 /* Initialize nc_path */
992 INIT_LIST_HEAD(&nc_path->packet_list);
993 spin_lock_init(&nc_path->packet_list_lock);
994 kref_init(&nc_path->refcount);
995 nc_path->last_valid = jiffies;
996 ether_addr_copy(nc_path->next_hop, dst);
997 ether_addr_copy(nc_path->prev_hop, src);
999 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
1003 /* Add nc_path to hash table */
1004 kref_get(&nc_path->refcount);
1005 hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
1006 batadv_nc_hash_choose, &nc_path_key,
1007 &nc_path->hash_entry);
1009 if (hash_added < 0) {
1018 * batadv_nc_random_weight_tq() - scale the receivers TQ-value to avoid unfair
1019 * selection of a receiver with slightly lower TQ than the other
1020 * @tq: to be weighted tq value
1022 * Return: scaled tq value
1024 static u8 batadv_nc_random_weight_tq(u8 tq)
1026 /* randomize the estimated packet loss (max TQ - estimated TQ) */
1027 u8 rand_tq = prandom_u32_max(BATADV_TQ_MAX_VALUE + 1 - tq);
1029 /* convert to (randomized) estimated tq again */
1030 return BATADV_TQ_MAX_VALUE - rand_tq;
1034 * batadv_nc_memxor() - XOR destination with source
1035 * @dst: byte array to XOR into
1036 * @src: byte array to XOR from
1037 * @len: length of destination array
1039 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
1043 for (i = 0; i < len; ++i)
1048 * batadv_nc_code_packets() - code a received unicast_packet with an nc packet
1049 * into a coded_packet and send it
1050 * @bat_priv: the bat priv with all the soft interface information
1051 * @skb: data skb to forward
1052 * @ethhdr: pointer to the ethernet header inside the skb
1053 * @nc_packet: structure containing the packet to the skb can be coded with
1054 * @neigh_node: next hop to forward packet to
1056 * Return: true if both packets are consumed, false otherwise.
1058 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1059 struct sk_buff *skb,
1060 struct ethhdr *ethhdr,
1061 struct batadv_nc_packet *nc_packet,
1062 struct batadv_neigh_node *neigh_node)
1064 u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1065 struct sk_buff *skb_dest, *skb_src;
1066 struct batadv_unicast_packet *packet1;
1067 struct batadv_unicast_packet *packet2;
1068 struct batadv_coded_packet *coded_packet;
1069 struct batadv_neigh_node *neigh_tmp, *router_neigh, *first_dest;
1070 struct batadv_neigh_node *router_coding = NULL, *second_dest;
1071 struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1072 struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1073 u8 *first_source, *second_source;
1074 __be32 packet_id1, packet_id2;
1078 int unicast_size = sizeof(*packet1);
1079 int coded_size = sizeof(*coded_packet);
1080 int header_add = coded_size - unicast_size;
1082 /* TODO: do we need to consider the outgoing interface for
1085 router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1090 router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1092 if (!router_neigh_ifinfo)
1095 neigh_tmp = nc_packet->neigh_node;
1096 router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1101 router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1103 if (!router_coding_ifinfo)
1106 tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1107 tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1108 tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1109 tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1111 /* Select one destination for the MAC-header dst-field based on
1112 * weighted TQ-values.
1114 if (tq_weighted_neigh >= tq_weighted_coding) {
1115 /* Destination from nc_packet is selected for MAC-header */
1116 first_dest = nc_packet->neigh_node;
1117 first_source = nc_packet->nc_path->prev_hop;
1118 second_dest = neigh_node;
1119 second_source = ethhdr->h_source;
1120 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1121 packet2 = (struct batadv_unicast_packet *)skb->data;
1122 packet_id1 = nc_packet->packet_id;
1123 packet_id2 = batadv_skb_crc32(skb,
1124 skb->data + sizeof(*packet2));
1126 /* Destination for skb is selected for MAC-header */
1127 first_dest = neigh_node;
1128 first_source = ethhdr->h_source;
1129 second_dest = nc_packet->neigh_node;
1130 second_source = nc_packet->nc_path->prev_hop;
1131 packet1 = (struct batadv_unicast_packet *)skb->data;
1132 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1133 packet_id1 = batadv_skb_crc32(skb,
1134 skb->data + sizeof(*packet1));
1135 packet_id2 = nc_packet->packet_id;
1138 /* Instead of zero padding the smallest data buffer, we
1139 * code into the largest.
1141 if (skb->len <= nc_packet->skb->len) {
1142 skb_dest = nc_packet->skb;
1146 skb_src = nc_packet->skb;
1149 /* coding_len is used when decoding the packet shorter packet */
1150 coding_len = skb_src->len - unicast_size;
1152 if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1155 skb_push(skb_dest, header_add);
1157 coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1158 skb_reset_mac_header(skb_dest);
1160 coded_packet->packet_type = BATADV_CODED;
1161 coded_packet->version = BATADV_COMPAT_VERSION;
1162 coded_packet->ttl = packet1->ttl;
1164 /* Info about first unicast packet */
1165 ether_addr_copy(coded_packet->first_source, first_source);
1166 ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1167 coded_packet->first_crc = packet_id1;
1168 coded_packet->first_ttvn = packet1->ttvn;
1170 /* Info about second unicast packet */
1171 ether_addr_copy(coded_packet->second_dest, second_dest->addr);
1172 ether_addr_copy(coded_packet->second_source, second_source);
1173 ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1174 coded_packet->second_crc = packet_id2;
1175 coded_packet->second_ttl = packet2->ttl;
1176 coded_packet->second_ttvn = packet2->ttvn;
1177 coded_packet->coded_len = htons(coding_len);
1179 /* This is where the magic happens: Code skb_src into skb_dest */
1180 batadv_nc_memxor(skb_dest->data + coded_size,
1181 skb_src->data + unicast_size, coding_len);
1183 /* Update counters accordingly */
1184 if (BATADV_SKB_CB(skb_src)->decoded &&
1185 BATADV_SKB_CB(skb_dest)->decoded) {
1186 /* Both packets are recoded */
1187 count = skb_src->len + ETH_HLEN;
1188 count += skb_dest->len + ETH_HLEN;
1189 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1190 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1191 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1192 !BATADV_SKB_CB(skb_dest)->decoded) {
1193 /* Both packets are newly coded */
1194 count = skb_src->len + ETH_HLEN;
1195 count += skb_dest->len + ETH_HLEN;
1196 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1197 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1198 } else if (BATADV_SKB_CB(skb_src)->decoded &&
1199 !BATADV_SKB_CB(skb_dest)->decoded) {
1200 /* skb_src recoded and skb_dest is newly coded */
1201 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1202 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1203 skb_src->len + ETH_HLEN);
1204 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1205 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1206 skb_dest->len + ETH_HLEN);
1207 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1208 BATADV_SKB_CB(skb_dest)->decoded) {
1209 /* skb_src is newly coded and skb_dest is recoded */
1210 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1211 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1212 skb_src->len + ETH_HLEN);
1213 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1214 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1215 skb_dest->len + ETH_HLEN);
1218 /* skb_src is now coded into skb_dest, so free it */
1219 consume_skb(skb_src);
1221 /* avoid duplicate free of skb from nc_packet */
1222 nc_packet->skb = NULL;
1223 batadv_nc_packet_free(nc_packet, false);
1225 /* Send the coded packet and return true */
1226 batadv_send_unicast_skb(skb_dest, first_dest);
1230 batadv_neigh_node_put(router_neigh);
1232 batadv_neigh_node_put(router_coding);
1233 if (router_neigh_ifinfo)
1234 batadv_neigh_ifinfo_put(router_neigh_ifinfo);
1235 if (router_coding_ifinfo)
1236 batadv_neigh_ifinfo_put(router_coding_ifinfo);
1241 * batadv_nc_skb_coding_possible() - true if a decoded skb is available at dst.
1242 * @skb: data skb to forward
1243 * @dst: destination mac address of the other skb to code with
1244 * @src: source mac address of skb
1246 * Whenever we network code a packet we have to check whether we received it in
1247 * a network coded form. If so, we may not be able to use it for coding because
1248 * some neighbors may also have received (overheard) the packet in the network
1249 * coded form without being able to decode it. It is hard to know which of the
1250 * neighboring nodes was able to decode the packet, therefore we can only
1251 * re-code the packet if the source of the previous encoded packet is involved.
1252 * Since the source encoded the packet we can be certain it has all necessary
1253 * decode information.
1255 * Return: true if coding of a decoded packet is allowed.
1257 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1259 if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1265 * batadv_nc_path_search() - Find the coding path matching in_nc_node and
1266 * out_nc_node to retrieve a buffered packet that can be used for coding.
1267 * @bat_priv: the bat priv with all the soft interface information
1268 * @in_nc_node: pointer to skb next hop's neighbor nc node
1269 * @out_nc_node: pointer to skb source's neighbor nc node
1270 * @skb: data skb to forward
1271 * @eth_dst: next hop mac address of skb
1273 * Return: true if coding of a decoded skb is allowed.
1275 static struct batadv_nc_packet *
1276 batadv_nc_path_search(struct batadv_priv *bat_priv,
1277 struct batadv_nc_node *in_nc_node,
1278 struct batadv_nc_node *out_nc_node,
1279 struct sk_buff *skb,
1282 struct batadv_nc_path *nc_path, nc_path_key;
1283 struct batadv_nc_packet *nc_packet_out = NULL;
1284 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1285 struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1291 /* Create almost path key */
1292 batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1294 idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1296 /* Check for coding opportunities in this nc_path */
1298 hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1299 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1302 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1305 spin_lock_bh(&nc_path->packet_list_lock);
1306 if (list_empty(&nc_path->packet_list)) {
1307 spin_unlock_bh(&nc_path->packet_list_lock);
1311 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1312 &nc_path->packet_list, list) {
1313 if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1318 /* Coding opportunity is found! */
1319 list_del(&nc_packet->list);
1320 nc_packet_out = nc_packet;
1324 spin_unlock_bh(&nc_path->packet_list_lock);
1329 return nc_packet_out;
1333 * batadv_nc_skb_src_search() - Loops through the list of neighoring nodes of
1334 * the skb's sender (may be equal to the originator).
1335 * @bat_priv: the bat priv with all the soft interface information
1336 * @skb: data skb to forward
1337 * @eth_dst: next hop mac address of skb
1338 * @eth_src: source mac address of skb
1339 * @in_nc_node: pointer to skb next hop's neighbor nc node
1341 * Return: an nc packet if a suitable coding packet was found, NULL otherwise.
1343 static struct batadv_nc_packet *
1344 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1345 struct sk_buff *skb,
1348 struct batadv_nc_node *in_nc_node)
1350 struct batadv_orig_node *orig_node;
1351 struct batadv_nc_node *out_nc_node;
1352 struct batadv_nc_packet *nc_packet = NULL;
1354 orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1359 list_for_each_entry_rcu(out_nc_node,
1360 &orig_node->out_coding_list, list) {
1361 /* Check if the skb is decoded and if recoding is possible */
1362 if (!batadv_nc_skb_coding_possible(skb,
1363 out_nc_node->addr, eth_src))
1366 /* Search for an opportunity in this nc_path */
1367 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1368 out_nc_node, skb, eth_dst);
1374 batadv_orig_node_put(orig_node);
1379 * batadv_nc_skb_store_before_coding() - set the ethernet src and dst of the
1380 * unicast skb before it is stored for use in later decoding
1381 * @bat_priv: the bat priv with all the soft interface information
1382 * @skb: data skb to store
1383 * @eth_dst_new: new destination mac address of skb
1385 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1386 struct sk_buff *skb,
1389 struct ethhdr *ethhdr;
1391 /* Copy skb header to change the mac header */
1392 skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1396 /* Set the mac header as if we actually sent the packet uncoded */
1397 ethhdr = eth_hdr(skb);
1398 ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1399 ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1401 /* Set data pointer to MAC header to mimic packets from our tx path */
1402 skb_push(skb, ETH_HLEN);
1404 /* Add the packet to the decoding packet pool */
1405 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1407 /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1414 * batadv_nc_skb_dst_search() - Loops through list of neighboring nodes to dst.
1415 * @skb: data skb to forward
1416 * @neigh_node: next hop to forward packet to
1417 * @ethhdr: pointer to the ethernet header inside the skb
1419 * Loops through list of neighboring nodes the next hop has a good connection to
1420 * (receives OGMs with a sufficient quality). We need to find a neighbor of our
1421 * next hop that potentially sent a packet which our next hop also received
1422 * (overheard) and has stored for later decoding.
1424 * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1426 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1427 struct batadv_neigh_node *neigh_node,
1428 struct ethhdr *ethhdr)
1430 struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1431 struct batadv_priv *bat_priv = netdev_priv(netdev);
1432 struct batadv_orig_node *orig_node = neigh_node->orig_node;
1433 struct batadv_nc_node *nc_node;
1434 struct batadv_nc_packet *nc_packet = NULL;
1437 list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1438 /* Search for coding opportunity with this in_nc_node */
1439 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1441 ethhdr->h_source, nc_node);
1443 /* Opportunity was found, so stop searching */
1452 /* Save packets for later decoding */
1453 batadv_nc_skb_store_before_coding(bat_priv, skb,
1455 batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1456 nc_packet->neigh_node->addr);
1458 /* Code and send packets */
1459 if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1463 /* out of mem ? Coding failed - we have to free the buffered packet
1464 * to avoid memleaks. The skb passed as argument will be dealt with
1465 * by the calling function.
1467 batadv_nc_send_packet(nc_packet);
1472 * batadv_nc_skb_add_to_path() - buffer skb for later encoding / decoding
1473 * @skb: skb to add to path
1474 * @nc_path: path to add skb to
1475 * @neigh_node: next hop to forward packet to
1476 * @packet_id: checksum to identify packet
1478 * Return: true if the packet was buffered or false in case of an error.
1480 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1481 struct batadv_nc_path *nc_path,
1482 struct batadv_neigh_node *neigh_node,
1485 struct batadv_nc_packet *nc_packet;
1487 nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1491 /* Initialize nc_packet */
1492 nc_packet->timestamp = jiffies;
1493 nc_packet->packet_id = packet_id;
1494 nc_packet->skb = skb;
1495 nc_packet->neigh_node = neigh_node;
1496 nc_packet->nc_path = nc_path;
1498 /* Add coding packet to list */
1499 spin_lock_bh(&nc_path->packet_list_lock);
1500 list_add_tail(&nc_packet->list, &nc_path->packet_list);
1501 spin_unlock_bh(&nc_path->packet_list_lock);
1507 * batadv_nc_skb_forward() - try to code a packet or add it to the coding packet
1509 * @skb: data skb to forward
1510 * @neigh_node: next hop to forward packet to
1512 * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1514 bool batadv_nc_skb_forward(struct sk_buff *skb,
1515 struct batadv_neigh_node *neigh_node)
1517 const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1518 struct batadv_priv *bat_priv = netdev_priv(netdev);
1519 struct batadv_unicast_packet *packet;
1520 struct batadv_nc_path *nc_path;
1521 struct ethhdr *ethhdr = eth_hdr(skb);
1525 /* Check if network coding is enabled */
1526 if (!atomic_read(&bat_priv->network_coding))
1529 /* We only handle unicast packets */
1530 payload = skb_network_header(skb);
1531 packet = (struct batadv_unicast_packet *)payload;
1532 if (packet->packet_type != BATADV_UNICAST)
1535 /* Try to find a coding opportunity and send the skb if one is found */
1536 if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1539 /* Find or create a nc_path for this src-dst pair */
1540 nc_path = batadv_nc_get_path(bat_priv,
1541 bat_priv->nc.coding_hash,
1548 /* Add skb to nc_path */
1549 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1550 if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1553 /* Packet is consumed */
1557 batadv_nc_path_put(nc_path);
1559 /* Packet is not consumed */
1564 * batadv_nc_skb_store_for_decoding() - save a clone of the skb which can be
1565 * used when decoding coded packets
1566 * @bat_priv: the bat priv with all the soft interface information
1567 * @skb: data skb to store
1569 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1570 struct sk_buff *skb)
1572 struct batadv_unicast_packet *packet;
1573 struct batadv_nc_path *nc_path;
1574 struct ethhdr *ethhdr = eth_hdr(skb);
1578 /* Check if network coding is enabled */
1579 if (!atomic_read(&bat_priv->network_coding))
1582 /* Check for supported packet type */
1583 payload = skb_network_header(skb);
1584 packet = (struct batadv_unicast_packet *)payload;
1585 if (packet->packet_type != BATADV_UNICAST)
1588 /* Find existing nc_path or create a new */
1589 nc_path = batadv_nc_get_path(bat_priv,
1590 bat_priv->nc.decoding_hash,
1597 /* Clone skb and adjust skb->data to point at batman header */
1598 skb = skb_clone(skb, GFP_ATOMIC);
1602 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1605 if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1608 /* Add skb to nc_path */
1609 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1610 if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1613 batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1619 batadv_nc_path_put(nc_path);
1625 * batadv_nc_skb_store_sniffed_unicast() - check if a received unicast packet
1626 * should be saved in the decoding buffer and, if so, store it there
1627 * @bat_priv: the bat priv with all the soft interface information
1628 * @skb: unicast skb to store
1630 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1631 struct sk_buff *skb)
1633 struct ethhdr *ethhdr = eth_hdr(skb);
1635 if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1638 /* Set data pointer to MAC header to mimic packets from our tx path */
1639 skb_push(skb, ETH_HLEN);
1641 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1645 * batadv_nc_skb_decode_packet() - decode given skb using the decode data stored
1647 * @bat_priv: the bat priv with all the soft interface information
1648 * @skb: unicast skb to decode
1649 * @nc_packet: decode data needed to decode the skb
1651 * Return: pointer to decoded unicast packet if the packet was decoded or NULL
1652 * in case of an error.
1654 static struct batadv_unicast_packet *
1655 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1656 struct batadv_nc_packet *nc_packet)
1658 const int h_size = sizeof(struct batadv_unicast_packet);
1659 const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1660 struct batadv_unicast_packet *unicast_packet;
1661 struct batadv_coded_packet coded_packet_tmp;
1662 struct ethhdr *ethhdr, ethhdr_tmp;
1663 u8 *orig_dest, ttl, ttvn;
1664 unsigned int coding_len;
1667 /* Save headers temporarily */
1668 memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1669 memcpy(ðhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1671 if (skb_cow(skb, 0) < 0)
1674 if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1677 /* Data points to batman header, so set mac header 14 bytes before
1678 * and network to data
1680 skb_set_mac_header(skb, -ETH_HLEN);
1681 skb_reset_network_header(skb);
1683 /* Reconstruct original mac header */
1684 ethhdr = eth_hdr(skb);
1685 *ethhdr = ethhdr_tmp;
1687 /* Select the correct unicast header information based on the location
1688 * of our mac address in the coded_packet header
1690 if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1691 /* If we are the second destination the packet was overheard,
1692 * so the Ethernet address must be copied to h_dest and
1693 * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1695 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1696 skb->pkt_type = PACKET_HOST;
1698 orig_dest = coded_packet_tmp.second_orig_dest;
1699 ttl = coded_packet_tmp.second_ttl;
1700 ttvn = coded_packet_tmp.second_ttvn;
1702 orig_dest = coded_packet_tmp.first_orig_dest;
1703 ttl = coded_packet_tmp.ttl;
1704 ttvn = coded_packet_tmp.first_ttvn;
1707 coding_len = ntohs(coded_packet_tmp.coded_len);
1709 if (coding_len > skb->len)
1712 /* Here the magic is reversed:
1713 * extract the missing packet from the received coded packet
1715 batadv_nc_memxor(skb->data + h_size,
1716 nc_packet->skb->data + h_size,
1719 /* Resize decoded skb if decoded with larger packet */
1720 if (nc_packet->skb->len > coding_len + h_size) {
1721 err = pskb_trim_rcsum(skb, coding_len + h_size);
1726 /* Create decoded unicast packet */
1727 unicast_packet = (struct batadv_unicast_packet *)skb->data;
1728 unicast_packet->packet_type = BATADV_UNICAST;
1729 unicast_packet->version = BATADV_COMPAT_VERSION;
1730 unicast_packet->ttl = ttl;
1731 ether_addr_copy(unicast_packet->dest, orig_dest);
1732 unicast_packet->ttvn = ttvn;
1734 batadv_nc_packet_free(nc_packet, false);
1735 return unicast_packet;
1739 * batadv_nc_find_decoding_packet() - search through buffered decoding data to
1740 * find the data needed to decode the coded packet
1741 * @bat_priv: the bat priv with all the soft interface information
1742 * @ethhdr: pointer to the ethernet header inside the coded packet
1743 * @coded: coded packet we try to find decode data for
1745 * Return: pointer to nc packet if the needed data was found or NULL otherwise.
1747 static struct batadv_nc_packet *
1748 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1749 struct ethhdr *ethhdr,
1750 struct batadv_coded_packet *coded)
1752 struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1753 struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1754 struct batadv_nc_path *nc_path, nc_path_key;
1762 /* Select the correct packet id based on the location of our mac-addr */
1763 dest = ethhdr->h_source;
1764 if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1765 source = coded->second_source;
1766 packet_id = coded->second_crc;
1768 source = coded->first_source;
1769 packet_id = coded->first_crc;
1772 batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1773 index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1775 /* Search for matching coding path */
1777 hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1778 /* Find matching nc_packet */
1779 spin_lock_bh(&nc_path->packet_list_lock);
1780 list_for_each_entry(tmp_nc_packet,
1781 &nc_path->packet_list, list) {
1782 if (packet_id == tmp_nc_packet->packet_id) {
1783 list_del(&tmp_nc_packet->list);
1785 nc_packet = tmp_nc_packet;
1789 spin_unlock_bh(&nc_path->packet_list_lock);
1797 batadv_dbg(BATADV_DBG_NC, bat_priv,
1798 "No decoding packet found for %u\n", packet_id);
1804 * batadv_nc_recv_coded_packet() - try to decode coded packet and enqueue the
1805 * resulting unicast packet
1806 * @skb: incoming coded packet
1807 * @recv_if: pointer to interface this packet was received on
1809 * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1812 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1813 struct batadv_hard_iface *recv_if)
1815 struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1816 struct batadv_unicast_packet *unicast_packet;
1817 struct batadv_coded_packet *coded_packet;
1818 struct batadv_nc_packet *nc_packet;
1819 struct ethhdr *ethhdr;
1820 int hdr_size = sizeof(*coded_packet);
1822 /* Check if network coding is enabled */
1823 if (!atomic_read(&bat_priv->network_coding))
1826 /* Make sure we can access (and remove) header */
1827 if (unlikely(!pskb_may_pull(skb, hdr_size)))
1830 coded_packet = (struct batadv_coded_packet *)skb->data;
1831 ethhdr = eth_hdr(skb);
1833 /* Verify frame is destined for us */
1834 if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1835 !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1838 /* Update stat counter */
1839 if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1840 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1842 nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1845 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1849 /* Make skb's linear, because decoding accesses the entire buffer */
1850 if (skb_linearize(skb) < 0)
1851 goto free_nc_packet;
1853 if (skb_linearize(nc_packet->skb) < 0)
1854 goto free_nc_packet;
1856 /* Decode the packet */
1857 unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1858 if (!unicast_packet) {
1859 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1860 goto free_nc_packet;
1863 /* Mark packet as decoded to do correct recoding when forwarding */
1864 BATADV_SKB_CB(skb)->decoded = true;
1865 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1866 batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1867 skb->len + ETH_HLEN);
1868 return batadv_recv_unicast_packet(skb, recv_if);
1871 batadv_nc_packet_free(nc_packet, true);
1879 * batadv_nc_mesh_free() - clean up network coding memory
1880 * @bat_priv: the bat priv with all the soft interface information
1882 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1884 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1885 batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1886 cancel_delayed_work_sync(&bat_priv->nc.work);
1888 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1889 batadv_hash_destroy(bat_priv->nc.coding_hash);
1890 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1891 batadv_hash_destroy(bat_priv->nc.decoding_hash);
1894 #ifdef CONFIG_BATMAN_ADV_DEBUGFS
1896 * batadv_nc_nodes_seq_print_text() - print the nc node information
1897 * @seq: seq file to print on
1902 int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
1904 struct net_device *net_dev = (struct net_device *)seq->private;
1905 struct batadv_priv *bat_priv = netdev_priv(net_dev);
1906 struct batadv_hashtable *hash = bat_priv->orig_hash;
1907 struct batadv_hard_iface *primary_if;
1908 struct hlist_head *head;
1909 struct batadv_orig_node *orig_node;
1910 struct batadv_nc_node *nc_node;
1913 primary_if = batadv_seq_print_text_primary_if_get(seq);
1917 /* Traverse list of originators */
1918 for (i = 0; i < hash->size; i++) {
1919 head = &hash->table[i];
1921 /* For each orig_node in this bin */
1923 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1924 /* no need to print the orig node if it does not have
1925 * network coding neighbors
1927 if (list_empty(&orig_node->in_coding_list) &&
1928 list_empty(&orig_node->out_coding_list))
1931 seq_printf(seq, "Node: %pM\n", orig_node->orig);
1933 seq_puts(seq, " Ingoing: ");
1934 /* For each in_nc_node to this orig_node */
1935 list_for_each_entry_rcu(nc_node,
1936 &orig_node->in_coding_list,
1938 seq_printf(seq, "%pM ",
1940 seq_puts(seq, "\n Outgoing: ");
1941 /* For out_nc_node to this orig_node */
1942 list_for_each_entry_rcu(nc_node,
1943 &orig_node->out_coding_list,
1945 seq_printf(seq, "%pM ",
1947 seq_puts(seq, "\n\n");
1954 batadv_hardif_put(primary_if);
1959 * batadv_nc_init_debugfs() - create nc folder and related files in debugfs
1960 * @bat_priv: the bat priv with all the soft interface information
1962 * Return: 0 on success or negative error number in case of failure
1964 int batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
1966 struct dentry *nc_dir, *file;
1968 nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
1972 file = debugfs_create_u8("min_tq", 0644, nc_dir, &bat_priv->nc.min_tq);
1976 file = debugfs_create_u32("max_fwd_delay", 0644, nc_dir,
1977 &bat_priv->nc.max_fwd_delay);
1981 file = debugfs_create_u32("max_buffer_time", 0644, nc_dir,
1982 &bat_priv->nc.max_buffer_time);