1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2012-2020 B.A.T.M.A.N. contributors:
4 * Martin Hundebøll, Jeppe Ledet-Pedersen
7 #include "network-coding.h"
10 #include <linux/atomic.h>
11 #include <linux/bitops.h>
12 #include <linux/byteorder/generic.h>
13 #include <linux/compiler.h>
14 #include <linux/debugfs.h>
15 #include <linux/errno.h>
16 #include <linux/etherdevice.h>
17 #include <linux/gfp.h>
18 #include <linux/if_ether.h>
19 #include <linux/if_packet.h>
20 #include <linux/init.h>
21 #include <linux/jhash.h>
22 #include <linux/jiffies.h>
23 #include <linux/kernel.h>
24 #include <linux/kref.h>
25 #include <linux/list.h>
26 #include <linux/lockdep.h>
27 #include <linux/net.h>
28 #include <linux/netdevice.h>
29 #include <linux/prandom.h>
30 #include <linux/printk.h>
31 #include <linux/rculist.h>
32 #include <linux/rcupdate.h>
33 #include <linux/seq_file.h>
34 #include <linux/skbuff.h>
35 #include <linux/slab.h>
36 #include <linux/spinlock.h>
37 #include <linux/stddef.h>
38 #include <linux/string.h>
39 #include <linux/workqueue.h>
40 #include <uapi/linux/batadv_packet.h>
42 #include "hard-interface.h"
45 #include "originator.h"
50 static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
51 static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
53 static void batadv_nc_worker(struct work_struct *work);
54 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
55 struct batadv_hard_iface *recv_if);
58 * batadv_nc_init() - one-time initialization for network coding
60 * Return: 0 on success or negative error number in case of failure
62 int __init batadv_nc_init(void)
66 /* Register our packet type */
67 ret = batadv_recv_handler_register(BATADV_CODED,
68 batadv_nc_recv_coded_packet);
74 * batadv_nc_start_timer() - initialise the nc periodic worker
75 * @bat_priv: the bat priv with all the soft interface information
77 static void batadv_nc_start_timer(struct batadv_priv *bat_priv)
79 queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work,
80 msecs_to_jiffies(10));
84 * batadv_nc_tvlv_container_update() - update the network coding tvlv container
85 * after network coding setting change
86 * @bat_priv: the bat priv with all the soft interface information
88 static void batadv_nc_tvlv_container_update(struct batadv_priv *bat_priv)
92 nc_mode = atomic_read(&bat_priv->network_coding);
96 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
99 batadv_tvlv_container_register(bat_priv, BATADV_TVLV_NC, 1,
106 * batadv_nc_status_update() - update the network coding tvlv container after
107 * network coding setting change
108 * @net_dev: the soft interface net device
110 void batadv_nc_status_update(struct net_device *net_dev)
112 struct batadv_priv *bat_priv = netdev_priv(net_dev);
114 batadv_nc_tvlv_container_update(bat_priv);
118 * batadv_nc_tvlv_ogm_handler_v1() - process incoming nc tvlv container
119 * @bat_priv: the bat priv with all the soft interface information
120 * @orig: the orig_node of the ogm
121 * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
122 * @tvlv_value: tvlv buffer containing the gateway data
123 * @tvlv_value_len: tvlv buffer length
125 static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
126 struct batadv_orig_node *orig,
128 void *tvlv_value, u16 tvlv_value_len)
130 if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
131 clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
133 set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
137 * batadv_nc_mesh_init() - initialise coding hash table and start housekeeping
138 * @bat_priv: the bat priv with all the soft interface information
140 * Return: 0 on success or negative error number in case of failure
142 int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
144 bat_priv->nc.timestamp_fwd_flush = jiffies;
145 bat_priv->nc.timestamp_sniffed_purge = jiffies;
147 if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
150 bat_priv->nc.coding_hash = batadv_hash_new(128);
151 if (!bat_priv->nc.coding_hash)
154 batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
155 &batadv_nc_coding_hash_lock_class_key);
157 bat_priv->nc.decoding_hash = batadv_hash_new(128);
158 if (!bat_priv->nc.decoding_hash) {
159 batadv_hash_destroy(bat_priv->nc.coding_hash);
163 batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
164 &batadv_nc_decoding_hash_lock_class_key);
166 INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
167 batadv_nc_start_timer(bat_priv);
169 batadv_tvlv_handler_register(bat_priv, batadv_nc_tvlv_ogm_handler_v1,
170 NULL, BATADV_TVLV_NC, 1,
171 BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
172 batadv_nc_tvlv_container_update(bat_priv);
180 * batadv_nc_init_bat_priv() - initialise the nc specific bat_priv variables
181 * @bat_priv: the bat priv with all the soft interface information
183 void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
185 atomic_set(&bat_priv->network_coding, 0);
186 bat_priv->nc.min_tq = 200;
187 bat_priv->nc.max_fwd_delay = 10;
188 bat_priv->nc.max_buffer_time = 200;
192 * batadv_nc_init_orig() - initialise the nc fields of an orig_node
193 * @orig_node: the orig_node which is going to be initialised
195 void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
197 INIT_LIST_HEAD(&orig_node->in_coding_list);
198 INIT_LIST_HEAD(&orig_node->out_coding_list);
199 spin_lock_init(&orig_node->in_coding_list_lock);
200 spin_lock_init(&orig_node->out_coding_list_lock);
204 * batadv_nc_node_release() - release nc_node from lists and queue for free
205 * after rcu grace period
206 * @ref: kref pointer of the nc_node
208 static void batadv_nc_node_release(struct kref *ref)
210 struct batadv_nc_node *nc_node;
212 nc_node = container_of(ref, struct batadv_nc_node, refcount);
214 batadv_orig_node_put(nc_node->orig_node);
215 kfree_rcu(nc_node, rcu);
219 * batadv_nc_node_put() - decrement the nc_node refcounter and possibly
221 * @nc_node: nc_node to be free'd
223 static void batadv_nc_node_put(struct batadv_nc_node *nc_node)
228 kref_put(&nc_node->refcount, batadv_nc_node_release);
232 * batadv_nc_path_release() - release nc_path from lists and queue for free
233 * after rcu grace period
234 * @ref: kref pointer of the nc_path
236 static void batadv_nc_path_release(struct kref *ref)
238 struct batadv_nc_path *nc_path;
240 nc_path = container_of(ref, struct batadv_nc_path, refcount);
242 kfree_rcu(nc_path, rcu);
246 * batadv_nc_path_put() - decrement the nc_path refcounter and possibly
248 * @nc_path: nc_path to be free'd
250 static void batadv_nc_path_put(struct batadv_nc_path *nc_path)
255 kref_put(&nc_path->refcount, batadv_nc_path_release);
259 * batadv_nc_packet_free() - frees nc packet
260 * @nc_packet: the nc packet to free
261 * @dropped: whether the packet is freed because is dropped
263 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet,
267 kfree_skb(nc_packet->skb);
269 consume_skb(nc_packet->skb);
271 batadv_nc_path_put(nc_packet->nc_path);
276 * batadv_nc_to_purge_nc_node() - checks whether an nc node has to be purged
277 * @bat_priv: the bat priv with all the soft interface information
278 * @nc_node: the nc node to check
280 * Return: true if the entry has to be purged now, false otherwise
282 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
283 struct batadv_nc_node *nc_node)
285 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
288 return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
292 * batadv_nc_to_purge_nc_path_coding() - checks whether an nc path has timed out
293 * @bat_priv: the bat priv with all the soft interface information
294 * @nc_path: the nc path to check
296 * Return: true if the entry has to be purged now, false otherwise
298 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
299 struct batadv_nc_path *nc_path)
301 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
304 /* purge the path when no packets has been added for 10 times the
307 return batadv_has_timed_out(nc_path->last_valid,
308 bat_priv->nc.max_fwd_delay * 10);
312 * batadv_nc_to_purge_nc_path_decoding() - checks whether an nc path has timed
314 * @bat_priv: the bat priv with all the soft interface information
315 * @nc_path: the nc path to check
317 * Return: true if the entry has to be purged now, false otherwise
319 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
320 struct batadv_nc_path *nc_path)
322 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
325 /* purge the path when no packets has been added for 10 times the
328 return batadv_has_timed_out(nc_path->last_valid,
329 bat_priv->nc.max_buffer_time * 10);
333 * batadv_nc_purge_orig_nc_nodes() - go through list of nc nodes and purge stale
335 * @bat_priv: the bat priv with all the soft interface information
336 * @list: list of nc nodes
337 * @lock: nc node list lock
338 * @to_purge: function in charge to decide whether an entry has to be purged or
339 * not. This function takes the nc node as argument and has to return
340 * a boolean value: true if the entry has to be deleted, false
344 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
345 struct list_head *list,
347 bool (*to_purge)(struct batadv_priv *,
348 struct batadv_nc_node *))
350 struct batadv_nc_node *nc_node, *nc_node_tmp;
352 /* For each nc_node in list */
354 list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
355 /* if an helper function has been passed as parameter,
356 * ask it if the entry has to be purged or not
358 if (to_purge && !to_purge(bat_priv, nc_node))
361 batadv_dbg(BATADV_DBG_NC, bat_priv,
362 "Removing nc_node %pM -> %pM\n",
363 nc_node->addr, nc_node->orig_node->orig);
364 list_del_rcu(&nc_node->list);
365 batadv_nc_node_put(nc_node);
367 spin_unlock_bh(lock);
371 * batadv_nc_purge_orig() - purges all nc node data attached of the given
373 * @bat_priv: the bat priv with all the soft interface information
374 * @orig_node: orig_node with the nc node entries to be purged
375 * @to_purge: function in charge to decide whether an entry has to be purged or
376 * not. This function takes the nc node as argument and has to return
377 * a boolean value: true is the entry has to be deleted, false
380 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
381 struct batadv_orig_node *orig_node,
382 bool (*to_purge)(struct batadv_priv *,
383 struct batadv_nc_node *))
385 /* Check ingoing nc_node's of this orig_node */
386 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
387 &orig_node->in_coding_list_lock,
390 /* Check outgoing nc_node's of this orig_node */
391 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
392 &orig_node->out_coding_list_lock,
397 * batadv_nc_purge_orig_hash() - traverse entire originator hash to check if
398 * they have timed out nc nodes
399 * @bat_priv: the bat priv with all the soft interface information
401 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
403 struct batadv_hashtable *hash = bat_priv->orig_hash;
404 struct hlist_head *head;
405 struct batadv_orig_node *orig_node;
411 /* For each orig_node */
412 for (i = 0; i < hash->size; i++) {
413 head = &hash->table[i];
416 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
417 batadv_nc_purge_orig(bat_priv, orig_node,
418 batadv_nc_to_purge_nc_node);
424 * batadv_nc_purge_paths() - traverse all nc paths part of the hash and remove
426 * @bat_priv: the bat priv with all the soft interface information
427 * @hash: hash table containing the nc paths to check
428 * @to_purge: function in charge to decide whether an entry has to be purged or
429 * not. This function takes the nc node as argument and has to return
430 * a boolean value: true is the entry has to be deleted, false
433 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
434 struct batadv_hashtable *hash,
435 bool (*to_purge)(struct batadv_priv *,
436 struct batadv_nc_path *))
438 struct hlist_head *head;
439 struct hlist_node *node_tmp;
440 struct batadv_nc_path *nc_path;
441 spinlock_t *lock; /* Protects lists in hash */
444 for (i = 0; i < hash->size; i++) {
445 head = &hash->table[i];
446 lock = &hash->list_locks[i];
448 /* For each nc_path in this bin */
450 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
451 /* if an helper function has been passed as parameter,
452 * ask it if the entry has to be purged or not
454 if (to_purge && !to_purge(bat_priv, nc_path))
457 /* purging an non-empty nc_path should never happen, but
458 * is observed under high CPU load. Delay the purging
459 * until next iteration to allow the packet_list to be
462 if (!unlikely(list_empty(&nc_path->packet_list))) {
463 net_ratelimited_function(printk,
465 "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
471 /* nc_path is unused, so remove it */
472 batadv_dbg(BATADV_DBG_NC, bat_priv,
473 "Remove nc_path %pM -> %pM\n",
474 nc_path->prev_hop, nc_path->next_hop);
475 hlist_del_rcu(&nc_path->hash_entry);
476 batadv_nc_path_put(nc_path);
478 spin_unlock_bh(lock);
483 * batadv_nc_hash_key_gen() - computes the nc_path hash key
484 * @key: buffer to hold the final hash key
485 * @src: source ethernet mac address going into the hash key
486 * @dst: destination ethernet mac address going into the hash key
488 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
491 memcpy(key->prev_hop, src, sizeof(key->prev_hop));
492 memcpy(key->next_hop, dst, sizeof(key->next_hop));
496 * batadv_nc_hash_choose() - compute the hash value for an nc path
497 * @data: data to hash
498 * @size: size of the hash table
500 * Return: the selected index in the hash table for the given data.
502 static u32 batadv_nc_hash_choose(const void *data, u32 size)
504 const struct batadv_nc_path *nc_path = data;
507 hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
508 hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
514 * batadv_nc_hash_compare() - comparing function used in the network coding hash
516 * @node: node in the local table
517 * @data2: second object to compare the node to
519 * Return: true if the two entry are the same, false otherwise
521 static bool batadv_nc_hash_compare(const struct hlist_node *node,
524 const struct batadv_nc_path *nc_path1, *nc_path2;
526 nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
529 /* Return 1 if the two keys are identical */
530 if (!batadv_compare_eth(nc_path1->prev_hop, nc_path2->prev_hop))
533 if (!batadv_compare_eth(nc_path1->next_hop, nc_path2->next_hop))
540 * batadv_nc_hash_find() - search for an existing nc path and return it
541 * @hash: hash table containing the nc path
544 * Return: the nc_path if found, NULL otherwise.
546 static struct batadv_nc_path *
547 batadv_nc_hash_find(struct batadv_hashtable *hash,
550 struct hlist_head *head;
551 struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
557 index = batadv_nc_hash_choose(data, hash->size);
558 head = &hash->table[index];
561 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
562 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
565 if (!kref_get_unless_zero(&nc_path->refcount))
568 nc_path_tmp = nc_path;
577 * batadv_nc_send_packet() - send non-coded packet and free nc_packet struct
578 * @nc_packet: the nc packet to send
580 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
582 batadv_send_unicast_skb(nc_packet->skb, nc_packet->neigh_node);
583 nc_packet->skb = NULL;
584 batadv_nc_packet_free(nc_packet, false);
588 * batadv_nc_sniffed_purge() - Checks timestamp of given sniffed nc_packet.
589 * @bat_priv: the bat priv with all the soft interface information
590 * @nc_path: the nc path the packet belongs to
591 * @nc_packet: the nc packet to be checked
593 * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
594 * timeout. If so, the packet is no longer kept and the entry deleted from the
595 * queue. Has to be called with the appropriate locks.
597 * Return: false as soon as the entry in the fifo queue has not been timed out
598 * yet and true otherwise.
600 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
601 struct batadv_nc_path *nc_path,
602 struct batadv_nc_packet *nc_packet)
604 unsigned long timeout = bat_priv->nc.max_buffer_time;
607 lockdep_assert_held(&nc_path->packet_list_lock);
609 /* Packets are added to tail, so the remaining packets did not time
610 * out and we can stop processing the current queue
612 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
613 !batadv_has_timed_out(nc_packet->timestamp, timeout))
616 /* purge nc packet */
617 list_del(&nc_packet->list);
618 batadv_nc_packet_free(nc_packet, true);
627 * batadv_nc_fwd_flush() - Checks the timestamp of the given nc packet.
628 * @bat_priv: the bat priv with all the soft interface information
629 * @nc_path: the nc path the packet belongs to
630 * @nc_packet: the nc packet to be checked
632 * Checks whether the given nc packet has hit its forward timeout. If so, the
633 * packet is no longer delayed, immediately sent and the entry deleted from the
634 * queue. Has to be called with the appropriate locks.
636 * Return: false as soon as the entry in the fifo queue has not been timed out
637 * yet and true otherwise.
639 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
640 struct batadv_nc_path *nc_path,
641 struct batadv_nc_packet *nc_packet)
643 unsigned long timeout = bat_priv->nc.max_fwd_delay;
645 lockdep_assert_held(&nc_path->packet_list_lock);
647 /* Packets are added to tail, so the remaining packets did not time
648 * out and we can stop processing the current queue
650 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
651 !batadv_has_timed_out(nc_packet->timestamp, timeout))
655 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
656 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
657 nc_packet->skb->len + ETH_HLEN);
658 list_del(&nc_packet->list);
659 batadv_nc_send_packet(nc_packet);
665 * batadv_nc_process_nc_paths() - traverse given nc packet pool and free timed
667 * @bat_priv: the bat priv with all the soft interface information
668 * @hash: to be processed hash table
669 * @process_fn: Function called to process given nc packet. Should return true
670 * to encourage this function to proceed with the next packet.
671 * Otherwise the rest of the current queue is skipped.
674 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
675 struct batadv_hashtable *hash,
676 bool (*process_fn)(struct batadv_priv *,
677 struct batadv_nc_path *,
678 struct batadv_nc_packet *))
680 struct hlist_head *head;
681 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
682 struct batadv_nc_path *nc_path;
689 /* Loop hash table bins */
690 for (i = 0; i < hash->size; i++) {
691 head = &hash->table[i];
693 /* Loop coding paths */
695 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
697 spin_lock_bh(&nc_path->packet_list_lock);
698 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
699 &nc_path->packet_list, list) {
700 ret = process_fn(bat_priv, nc_path, nc_packet);
704 spin_unlock_bh(&nc_path->packet_list_lock);
711 * batadv_nc_worker() - periodic task for housekeeping related to network
713 * @work: kernel work struct
715 static void batadv_nc_worker(struct work_struct *work)
717 struct delayed_work *delayed_work;
718 struct batadv_priv_nc *priv_nc;
719 struct batadv_priv *bat_priv;
720 unsigned long timeout;
722 delayed_work = to_delayed_work(work);
723 priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
724 bat_priv = container_of(priv_nc, struct batadv_priv, nc);
726 batadv_nc_purge_orig_hash(bat_priv);
727 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
728 batadv_nc_to_purge_nc_path_coding);
729 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
730 batadv_nc_to_purge_nc_path_decoding);
732 timeout = bat_priv->nc.max_fwd_delay;
734 if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
735 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
736 batadv_nc_fwd_flush);
737 bat_priv->nc.timestamp_fwd_flush = jiffies;
740 if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
741 bat_priv->nc.max_buffer_time)) {
742 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
743 batadv_nc_sniffed_purge);
744 bat_priv->nc.timestamp_sniffed_purge = jiffies;
747 /* Schedule a new check */
748 batadv_nc_start_timer(bat_priv);
752 * batadv_can_nc_with_orig() - checks whether the given orig node is suitable
754 * @bat_priv: the bat priv with all the soft interface information
755 * @orig_node: neighboring orig node which may be used as nc candidate
756 * @ogm_packet: incoming ogm packet also used for the checks
759 * 1) The OGM must have the most recent sequence number.
760 * 2) The TTL must be decremented by one and only one.
761 * 3) The OGM must be received from the first hop from orig_node.
762 * 4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
764 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
765 struct batadv_orig_node *orig_node,
766 struct batadv_ogm_packet *ogm_packet)
768 struct batadv_orig_ifinfo *orig_ifinfo;
772 orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
776 last_ttl = orig_ifinfo->last_ttl;
777 last_real_seqno = orig_ifinfo->last_real_seqno;
778 batadv_orig_ifinfo_put(orig_ifinfo);
780 if (last_real_seqno != ntohl(ogm_packet->seqno))
782 if (last_ttl != ogm_packet->ttl + 1)
784 if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
786 if (ogm_packet->tq < bat_priv->nc.min_tq)
793 * batadv_nc_find_nc_node() - search for an existing nc node and return it
794 * @orig_node: orig node originating the ogm packet
795 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
796 * (can be equal to orig_node)
797 * @in_coding: traverse incoming or outgoing network coding list
799 * Return: the nc_node if found, NULL otherwise.
801 static struct batadv_nc_node *
802 batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
803 struct batadv_orig_node *orig_neigh_node,
806 struct batadv_nc_node *nc_node, *nc_node_out = NULL;
807 struct list_head *list;
810 list = &orig_neigh_node->in_coding_list;
812 list = &orig_neigh_node->out_coding_list;
814 /* Traverse list of nc_nodes to orig_node */
816 list_for_each_entry_rcu(nc_node, list, list) {
817 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
820 if (!kref_get_unless_zero(&nc_node->refcount))
824 nc_node_out = nc_node;
833 * batadv_nc_get_nc_node() - retrieves an nc node or creates the entry if it was
835 * @bat_priv: the bat priv with all the soft interface information
836 * @orig_node: orig node originating the ogm packet
837 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
838 * (can be equal to orig_node)
839 * @in_coding: traverse incoming or outgoing network coding list
841 * Return: the nc_node if found or created, NULL in case of an error.
843 static struct batadv_nc_node *
844 batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
845 struct batadv_orig_node *orig_node,
846 struct batadv_orig_node *orig_neigh_node,
849 struct batadv_nc_node *nc_node;
850 spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
851 struct list_head *list;
853 /* Select ingoing or outgoing coding node */
855 lock = &orig_neigh_node->in_coding_list_lock;
856 list = &orig_neigh_node->in_coding_list;
858 lock = &orig_neigh_node->out_coding_list_lock;
859 list = &orig_neigh_node->out_coding_list;
864 /* Check if nc_node is already added */
865 nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
871 nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
875 /* Initialize nc_node */
876 INIT_LIST_HEAD(&nc_node->list);
877 kref_init(&nc_node->refcount);
878 ether_addr_copy(nc_node->addr, orig_node->orig);
879 kref_get(&orig_neigh_node->refcount);
880 nc_node->orig_node = orig_neigh_node;
882 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
883 nc_node->addr, nc_node->orig_node->orig);
885 /* Add nc_node to orig_node */
886 kref_get(&nc_node->refcount);
887 list_add_tail_rcu(&nc_node->list, list);
890 spin_unlock_bh(lock);
896 * batadv_nc_update_nc_node() - updates stored incoming and outgoing nc node
897 * structs (best called on incoming OGMs)
898 * @bat_priv: the bat priv with all the soft interface information
899 * @orig_node: orig node originating the ogm packet
900 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
901 * (can be equal to orig_node)
902 * @ogm_packet: incoming ogm packet
903 * @is_single_hop_neigh: orig_node is a single hop neighbor
905 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
906 struct batadv_orig_node *orig_node,
907 struct batadv_orig_node *orig_neigh_node,
908 struct batadv_ogm_packet *ogm_packet,
909 int is_single_hop_neigh)
911 struct batadv_nc_node *in_nc_node = NULL;
912 struct batadv_nc_node *out_nc_node = NULL;
914 /* Check if network coding is enabled */
915 if (!atomic_read(&bat_priv->network_coding))
918 /* check if orig node is network coding enabled */
919 if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
922 /* accept ogms from 'good' neighbors and single hop neighbors */
923 if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
924 !is_single_hop_neigh)
927 /* Add orig_node as in_nc_node on hop */
928 in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
929 orig_neigh_node, true);
933 in_nc_node->last_seen = jiffies;
935 /* Add hop as out_nc_node on orig_node */
936 out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
941 out_nc_node->last_seen = jiffies;
945 batadv_nc_node_put(in_nc_node);
947 batadv_nc_node_put(out_nc_node);
951 * batadv_nc_get_path() - get existing nc_path or allocate a new one
952 * @bat_priv: the bat priv with all the soft interface information
953 * @hash: hash table containing the nc path
954 * @src: ethernet source address - first half of the nc path search key
955 * @dst: ethernet destination address - second half of the nc path search key
957 * Return: pointer to nc_path if the path was found or created, returns NULL
960 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
961 struct batadv_hashtable *hash,
966 struct batadv_nc_path *nc_path, nc_path_key;
968 batadv_nc_hash_key_gen(&nc_path_key, src, dst);
970 /* Search for existing nc_path */
971 nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
974 /* Set timestamp to delay removal of nc_path */
975 nc_path->last_valid = jiffies;
979 /* No existing nc_path was found; create a new */
980 nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
985 /* Initialize nc_path */
986 INIT_LIST_HEAD(&nc_path->packet_list);
987 spin_lock_init(&nc_path->packet_list_lock);
988 kref_init(&nc_path->refcount);
989 nc_path->last_valid = jiffies;
990 ether_addr_copy(nc_path->next_hop, dst);
991 ether_addr_copy(nc_path->prev_hop, src);
993 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
997 /* Add nc_path to hash table */
998 kref_get(&nc_path->refcount);
999 hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
1000 batadv_nc_hash_choose, &nc_path_key,
1001 &nc_path->hash_entry);
1003 if (hash_added < 0) {
1012 * batadv_nc_random_weight_tq() - scale the receivers TQ-value to avoid unfair
1013 * selection of a receiver with slightly lower TQ than the other
1014 * @tq: to be weighted tq value
1016 * Return: scaled tq value
1018 static u8 batadv_nc_random_weight_tq(u8 tq)
1020 /* randomize the estimated packet loss (max TQ - estimated TQ) */
1021 u8 rand_tq = prandom_u32_max(BATADV_TQ_MAX_VALUE + 1 - tq);
1023 /* convert to (randomized) estimated tq again */
1024 return BATADV_TQ_MAX_VALUE - rand_tq;
1028 * batadv_nc_memxor() - XOR destination with source
1029 * @dst: byte array to XOR into
1030 * @src: byte array to XOR from
1031 * @len: length of destination array
1033 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
1037 for (i = 0; i < len; ++i)
1042 * batadv_nc_code_packets() - code a received unicast_packet with an nc packet
1043 * into a coded_packet and send it
1044 * @bat_priv: the bat priv with all the soft interface information
1045 * @skb: data skb to forward
1046 * @ethhdr: pointer to the ethernet header inside the skb
1047 * @nc_packet: structure containing the packet to the skb can be coded with
1048 * @neigh_node: next hop to forward packet to
1050 * Return: true if both packets are consumed, false otherwise.
1052 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1053 struct sk_buff *skb,
1054 struct ethhdr *ethhdr,
1055 struct batadv_nc_packet *nc_packet,
1056 struct batadv_neigh_node *neigh_node)
1058 u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1059 struct sk_buff *skb_dest, *skb_src;
1060 struct batadv_unicast_packet *packet1;
1061 struct batadv_unicast_packet *packet2;
1062 struct batadv_coded_packet *coded_packet;
1063 struct batadv_neigh_node *neigh_tmp, *router_neigh, *first_dest;
1064 struct batadv_neigh_node *router_coding = NULL, *second_dest;
1065 struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1066 struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1067 u8 *first_source, *second_source;
1068 __be32 packet_id1, packet_id2;
1072 int unicast_size = sizeof(*packet1);
1073 int coded_size = sizeof(*coded_packet);
1074 int header_add = coded_size - unicast_size;
1076 /* TODO: do we need to consider the outgoing interface for
1079 router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1084 router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1086 if (!router_neigh_ifinfo)
1089 neigh_tmp = nc_packet->neigh_node;
1090 router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1095 router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1097 if (!router_coding_ifinfo)
1100 tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1101 tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1102 tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1103 tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1105 /* Select one destination for the MAC-header dst-field based on
1106 * weighted TQ-values.
1108 if (tq_weighted_neigh >= tq_weighted_coding) {
1109 /* Destination from nc_packet is selected for MAC-header */
1110 first_dest = nc_packet->neigh_node;
1111 first_source = nc_packet->nc_path->prev_hop;
1112 second_dest = neigh_node;
1113 second_source = ethhdr->h_source;
1114 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1115 packet2 = (struct batadv_unicast_packet *)skb->data;
1116 packet_id1 = nc_packet->packet_id;
1117 packet_id2 = batadv_skb_crc32(skb,
1118 skb->data + sizeof(*packet2));
1120 /* Destination for skb is selected for MAC-header */
1121 first_dest = neigh_node;
1122 first_source = ethhdr->h_source;
1123 second_dest = nc_packet->neigh_node;
1124 second_source = nc_packet->nc_path->prev_hop;
1125 packet1 = (struct batadv_unicast_packet *)skb->data;
1126 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1127 packet_id1 = batadv_skb_crc32(skb,
1128 skb->data + sizeof(*packet1));
1129 packet_id2 = nc_packet->packet_id;
1132 /* Instead of zero padding the smallest data buffer, we
1133 * code into the largest.
1135 if (skb->len <= nc_packet->skb->len) {
1136 skb_dest = nc_packet->skb;
1140 skb_src = nc_packet->skb;
1143 /* coding_len is used when decoding the packet shorter packet */
1144 coding_len = skb_src->len - unicast_size;
1146 if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1149 skb_push(skb_dest, header_add);
1151 coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1152 skb_reset_mac_header(skb_dest);
1154 coded_packet->packet_type = BATADV_CODED;
1155 coded_packet->version = BATADV_COMPAT_VERSION;
1156 coded_packet->ttl = packet1->ttl;
1158 /* Info about first unicast packet */
1159 ether_addr_copy(coded_packet->first_source, first_source);
1160 ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1161 coded_packet->first_crc = packet_id1;
1162 coded_packet->first_ttvn = packet1->ttvn;
1164 /* Info about second unicast packet */
1165 ether_addr_copy(coded_packet->second_dest, second_dest->addr);
1166 ether_addr_copy(coded_packet->second_source, second_source);
1167 ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1168 coded_packet->second_crc = packet_id2;
1169 coded_packet->second_ttl = packet2->ttl;
1170 coded_packet->second_ttvn = packet2->ttvn;
1171 coded_packet->coded_len = htons(coding_len);
1173 /* This is where the magic happens: Code skb_src into skb_dest */
1174 batadv_nc_memxor(skb_dest->data + coded_size,
1175 skb_src->data + unicast_size, coding_len);
1177 /* Update counters accordingly */
1178 if (BATADV_SKB_CB(skb_src)->decoded &&
1179 BATADV_SKB_CB(skb_dest)->decoded) {
1180 /* Both packets are recoded */
1181 count = skb_src->len + ETH_HLEN;
1182 count += skb_dest->len + ETH_HLEN;
1183 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1184 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1185 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1186 !BATADV_SKB_CB(skb_dest)->decoded) {
1187 /* Both packets are newly coded */
1188 count = skb_src->len + ETH_HLEN;
1189 count += skb_dest->len + ETH_HLEN;
1190 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1191 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1192 } else if (BATADV_SKB_CB(skb_src)->decoded &&
1193 !BATADV_SKB_CB(skb_dest)->decoded) {
1194 /* skb_src recoded and skb_dest is newly coded */
1195 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1196 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1197 skb_src->len + ETH_HLEN);
1198 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1199 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1200 skb_dest->len + ETH_HLEN);
1201 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1202 BATADV_SKB_CB(skb_dest)->decoded) {
1203 /* skb_src is newly coded and skb_dest is recoded */
1204 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1205 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1206 skb_src->len + ETH_HLEN);
1207 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1208 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1209 skb_dest->len + ETH_HLEN);
1212 /* skb_src is now coded into skb_dest, so free it */
1213 consume_skb(skb_src);
1215 /* avoid duplicate free of skb from nc_packet */
1216 nc_packet->skb = NULL;
1217 batadv_nc_packet_free(nc_packet, false);
1219 /* Send the coded packet and return true */
1220 batadv_send_unicast_skb(skb_dest, first_dest);
1224 batadv_neigh_node_put(router_neigh);
1226 batadv_neigh_node_put(router_coding);
1227 if (router_neigh_ifinfo)
1228 batadv_neigh_ifinfo_put(router_neigh_ifinfo);
1229 if (router_coding_ifinfo)
1230 batadv_neigh_ifinfo_put(router_coding_ifinfo);
1235 * batadv_nc_skb_coding_possible() - true if a decoded skb is available at dst.
1236 * @skb: data skb to forward
1237 * @dst: destination mac address of the other skb to code with
1238 * @src: source mac address of skb
1240 * Whenever we network code a packet we have to check whether we received it in
1241 * a network coded form. If so, we may not be able to use it for coding because
1242 * some neighbors may also have received (overheard) the packet in the network
1243 * coded form without being able to decode it. It is hard to know which of the
1244 * neighboring nodes was able to decode the packet, therefore we can only
1245 * re-code the packet if the source of the previous encoded packet is involved.
1246 * Since the source encoded the packet we can be certain it has all necessary
1247 * decode information.
1249 * Return: true if coding of a decoded packet is allowed.
1251 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1253 if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1259 * batadv_nc_path_search() - Find the coding path matching in_nc_node and
1260 * out_nc_node to retrieve a buffered packet that can be used for coding.
1261 * @bat_priv: the bat priv with all the soft interface information
1262 * @in_nc_node: pointer to skb next hop's neighbor nc node
1263 * @out_nc_node: pointer to skb source's neighbor nc node
1264 * @skb: data skb to forward
1265 * @eth_dst: next hop mac address of skb
1267 * Return: true if coding of a decoded skb is allowed.
1269 static struct batadv_nc_packet *
1270 batadv_nc_path_search(struct batadv_priv *bat_priv,
1271 struct batadv_nc_node *in_nc_node,
1272 struct batadv_nc_node *out_nc_node,
1273 struct sk_buff *skb,
1276 struct batadv_nc_path *nc_path, nc_path_key;
1277 struct batadv_nc_packet *nc_packet_out = NULL;
1278 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1279 struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1285 /* Create almost path key */
1286 batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1288 idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1290 /* Check for coding opportunities in this nc_path */
1292 hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1293 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1296 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1299 spin_lock_bh(&nc_path->packet_list_lock);
1300 if (list_empty(&nc_path->packet_list)) {
1301 spin_unlock_bh(&nc_path->packet_list_lock);
1305 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1306 &nc_path->packet_list, list) {
1307 if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1312 /* Coding opportunity is found! */
1313 list_del(&nc_packet->list);
1314 nc_packet_out = nc_packet;
1318 spin_unlock_bh(&nc_path->packet_list_lock);
1323 return nc_packet_out;
1327 * batadv_nc_skb_src_search() - Loops through the list of neighboring nodes of
1328 * the skb's sender (may be equal to the originator).
1329 * @bat_priv: the bat priv with all the soft interface information
1330 * @skb: data skb to forward
1331 * @eth_dst: next hop mac address of skb
1332 * @eth_src: source mac address of skb
1333 * @in_nc_node: pointer to skb next hop's neighbor nc node
1335 * Return: an nc packet if a suitable coding packet was found, NULL otherwise.
1337 static struct batadv_nc_packet *
1338 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1339 struct sk_buff *skb,
1342 struct batadv_nc_node *in_nc_node)
1344 struct batadv_orig_node *orig_node;
1345 struct batadv_nc_node *out_nc_node;
1346 struct batadv_nc_packet *nc_packet = NULL;
1348 orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1353 list_for_each_entry_rcu(out_nc_node,
1354 &orig_node->out_coding_list, list) {
1355 /* Check if the skb is decoded and if recoding is possible */
1356 if (!batadv_nc_skb_coding_possible(skb,
1357 out_nc_node->addr, eth_src))
1360 /* Search for an opportunity in this nc_path */
1361 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1362 out_nc_node, skb, eth_dst);
1368 batadv_orig_node_put(orig_node);
1373 * batadv_nc_skb_store_before_coding() - set the ethernet src and dst of the
1374 * unicast skb before it is stored for use in later decoding
1375 * @bat_priv: the bat priv with all the soft interface information
1376 * @skb: data skb to store
1377 * @eth_dst_new: new destination mac address of skb
1379 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1380 struct sk_buff *skb,
1383 struct ethhdr *ethhdr;
1385 /* Copy skb header to change the mac header */
1386 skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1390 /* Set the mac header as if we actually sent the packet uncoded */
1391 ethhdr = eth_hdr(skb);
1392 ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1393 ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1395 /* Set data pointer to MAC header to mimic packets from our tx path */
1396 skb_push(skb, ETH_HLEN);
1398 /* Add the packet to the decoding packet pool */
1399 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1401 /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1408 * batadv_nc_skb_dst_search() - Loops through list of neighboring nodes to dst.
1409 * @skb: data skb to forward
1410 * @neigh_node: next hop to forward packet to
1411 * @ethhdr: pointer to the ethernet header inside the skb
1413 * Loops through the list of neighboring nodes the next hop has a good
1414 * connection to (receives OGMs with a sufficient quality). We need to find a
1415 * neighbor of our next hop that potentially sent a packet which our next hop
1416 * also received (overheard) and has stored for later decoding.
1418 * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1420 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1421 struct batadv_neigh_node *neigh_node,
1422 struct ethhdr *ethhdr)
1424 struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1425 struct batadv_priv *bat_priv = netdev_priv(netdev);
1426 struct batadv_orig_node *orig_node = neigh_node->orig_node;
1427 struct batadv_nc_node *nc_node;
1428 struct batadv_nc_packet *nc_packet = NULL;
1431 list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1432 /* Search for coding opportunity with this in_nc_node */
1433 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1435 ethhdr->h_source, nc_node);
1437 /* Opportunity was found, so stop searching */
1446 /* Save packets for later decoding */
1447 batadv_nc_skb_store_before_coding(bat_priv, skb,
1449 batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1450 nc_packet->neigh_node->addr);
1452 /* Code and send packets */
1453 if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1457 /* out of mem ? Coding failed - we have to free the buffered packet
1458 * to avoid memleaks. The skb passed as argument will be dealt with
1459 * by the calling function.
1461 batadv_nc_send_packet(nc_packet);
1466 * batadv_nc_skb_add_to_path() - buffer skb for later encoding / decoding
1467 * @skb: skb to add to path
1468 * @nc_path: path to add skb to
1469 * @neigh_node: next hop to forward packet to
1470 * @packet_id: checksum to identify packet
1472 * Return: true if the packet was buffered or false in case of an error.
1474 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1475 struct batadv_nc_path *nc_path,
1476 struct batadv_neigh_node *neigh_node,
1479 struct batadv_nc_packet *nc_packet;
1481 nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1485 /* Initialize nc_packet */
1486 nc_packet->timestamp = jiffies;
1487 nc_packet->packet_id = packet_id;
1488 nc_packet->skb = skb;
1489 nc_packet->neigh_node = neigh_node;
1490 nc_packet->nc_path = nc_path;
1492 /* Add coding packet to list */
1493 spin_lock_bh(&nc_path->packet_list_lock);
1494 list_add_tail(&nc_packet->list, &nc_path->packet_list);
1495 spin_unlock_bh(&nc_path->packet_list_lock);
1501 * batadv_nc_skb_forward() - try to code a packet or add it to the coding packet
1503 * @skb: data skb to forward
1504 * @neigh_node: next hop to forward packet to
1506 * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1508 bool batadv_nc_skb_forward(struct sk_buff *skb,
1509 struct batadv_neigh_node *neigh_node)
1511 const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1512 struct batadv_priv *bat_priv = netdev_priv(netdev);
1513 struct batadv_unicast_packet *packet;
1514 struct batadv_nc_path *nc_path;
1515 struct ethhdr *ethhdr = eth_hdr(skb);
1519 /* Check if network coding is enabled */
1520 if (!atomic_read(&bat_priv->network_coding))
1523 /* We only handle unicast packets */
1524 payload = skb_network_header(skb);
1525 packet = (struct batadv_unicast_packet *)payload;
1526 if (packet->packet_type != BATADV_UNICAST)
1529 /* Try to find a coding opportunity and send the skb if one is found */
1530 if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1533 /* Find or create a nc_path for this src-dst pair */
1534 nc_path = batadv_nc_get_path(bat_priv,
1535 bat_priv->nc.coding_hash,
1542 /* Add skb to nc_path */
1543 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1544 if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1547 /* Packet is consumed */
1551 batadv_nc_path_put(nc_path);
1553 /* Packet is not consumed */
1558 * batadv_nc_skb_store_for_decoding() - save a clone of the skb which can be
1559 * used when decoding coded packets
1560 * @bat_priv: the bat priv with all the soft interface information
1561 * @skb: data skb to store
1563 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1564 struct sk_buff *skb)
1566 struct batadv_unicast_packet *packet;
1567 struct batadv_nc_path *nc_path;
1568 struct ethhdr *ethhdr = eth_hdr(skb);
1572 /* Check if network coding is enabled */
1573 if (!atomic_read(&bat_priv->network_coding))
1576 /* Check for supported packet type */
1577 payload = skb_network_header(skb);
1578 packet = (struct batadv_unicast_packet *)payload;
1579 if (packet->packet_type != BATADV_UNICAST)
1582 /* Find existing nc_path or create a new */
1583 nc_path = batadv_nc_get_path(bat_priv,
1584 bat_priv->nc.decoding_hash,
1591 /* Clone skb and adjust skb->data to point at batman header */
1592 skb = skb_clone(skb, GFP_ATOMIC);
1596 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1599 if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1602 /* Add skb to nc_path */
1603 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1604 if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1607 batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1613 batadv_nc_path_put(nc_path);
1619 * batadv_nc_skb_store_sniffed_unicast() - check if a received unicast packet
1620 * should be saved in the decoding buffer and, if so, store it there
1621 * @bat_priv: the bat priv with all the soft interface information
1622 * @skb: unicast skb to store
1624 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1625 struct sk_buff *skb)
1627 struct ethhdr *ethhdr = eth_hdr(skb);
1629 if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1632 /* Set data pointer to MAC header to mimic packets from our tx path */
1633 skb_push(skb, ETH_HLEN);
1635 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1639 * batadv_nc_skb_decode_packet() - decode given skb using the decode data stored
1641 * @bat_priv: the bat priv with all the soft interface information
1642 * @skb: unicast skb to decode
1643 * @nc_packet: decode data needed to decode the skb
1645 * Return: pointer to decoded unicast packet if the packet was decoded or NULL
1646 * in case of an error.
1648 static struct batadv_unicast_packet *
1649 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1650 struct batadv_nc_packet *nc_packet)
1652 const int h_size = sizeof(struct batadv_unicast_packet);
1653 const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1654 struct batadv_unicast_packet *unicast_packet;
1655 struct batadv_coded_packet coded_packet_tmp;
1656 struct ethhdr *ethhdr, ethhdr_tmp;
1657 u8 *orig_dest, ttl, ttvn;
1658 unsigned int coding_len;
1661 /* Save headers temporarily */
1662 memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1663 memcpy(ðhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1665 if (skb_cow(skb, 0) < 0)
1668 if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1671 /* Data points to batman header, so set mac header 14 bytes before
1672 * and network to data
1674 skb_set_mac_header(skb, -ETH_HLEN);
1675 skb_reset_network_header(skb);
1677 /* Reconstruct original mac header */
1678 ethhdr = eth_hdr(skb);
1679 *ethhdr = ethhdr_tmp;
1681 /* Select the correct unicast header information based on the location
1682 * of our mac address in the coded_packet header
1684 if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1685 /* If we are the second destination the packet was overheard,
1686 * so the Ethernet address must be copied to h_dest and
1687 * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1689 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1690 skb->pkt_type = PACKET_HOST;
1692 orig_dest = coded_packet_tmp.second_orig_dest;
1693 ttl = coded_packet_tmp.second_ttl;
1694 ttvn = coded_packet_tmp.second_ttvn;
1696 orig_dest = coded_packet_tmp.first_orig_dest;
1697 ttl = coded_packet_tmp.ttl;
1698 ttvn = coded_packet_tmp.first_ttvn;
1701 coding_len = ntohs(coded_packet_tmp.coded_len);
1703 if (coding_len > skb->len)
1706 /* Here the magic is reversed:
1707 * extract the missing packet from the received coded packet
1709 batadv_nc_memxor(skb->data + h_size,
1710 nc_packet->skb->data + h_size,
1713 /* Resize decoded skb if decoded with larger packet */
1714 if (nc_packet->skb->len > coding_len + h_size) {
1715 err = pskb_trim_rcsum(skb, coding_len + h_size);
1720 /* Create decoded unicast packet */
1721 unicast_packet = (struct batadv_unicast_packet *)skb->data;
1722 unicast_packet->packet_type = BATADV_UNICAST;
1723 unicast_packet->version = BATADV_COMPAT_VERSION;
1724 unicast_packet->ttl = ttl;
1725 ether_addr_copy(unicast_packet->dest, orig_dest);
1726 unicast_packet->ttvn = ttvn;
1728 batadv_nc_packet_free(nc_packet, false);
1729 return unicast_packet;
1733 * batadv_nc_find_decoding_packet() - search through buffered decoding data to
1734 * find the data needed to decode the coded packet
1735 * @bat_priv: the bat priv with all the soft interface information
1736 * @ethhdr: pointer to the ethernet header inside the coded packet
1737 * @coded: coded packet we try to find decode data for
1739 * Return: pointer to nc packet if the needed data was found or NULL otherwise.
1741 static struct batadv_nc_packet *
1742 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1743 struct ethhdr *ethhdr,
1744 struct batadv_coded_packet *coded)
1746 struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1747 struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1748 struct batadv_nc_path *nc_path, nc_path_key;
1756 /* Select the correct packet id based on the location of our mac-addr */
1757 dest = ethhdr->h_source;
1758 if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1759 source = coded->second_source;
1760 packet_id = coded->second_crc;
1762 source = coded->first_source;
1763 packet_id = coded->first_crc;
1766 batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1767 index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1769 /* Search for matching coding path */
1771 hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1772 /* Find matching nc_packet */
1773 spin_lock_bh(&nc_path->packet_list_lock);
1774 list_for_each_entry(tmp_nc_packet,
1775 &nc_path->packet_list, list) {
1776 if (packet_id == tmp_nc_packet->packet_id) {
1777 list_del(&tmp_nc_packet->list);
1779 nc_packet = tmp_nc_packet;
1783 spin_unlock_bh(&nc_path->packet_list_lock);
1791 batadv_dbg(BATADV_DBG_NC, bat_priv,
1792 "No decoding packet found for %u\n", packet_id);
1798 * batadv_nc_recv_coded_packet() - try to decode coded packet and enqueue the
1799 * resulting unicast packet
1800 * @skb: incoming coded packet
1801 * @recv_if: pointer to interface this packet was received on
1803 * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1806 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1807 struct batadv_hard_iface *recv_if)
1809 struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1810 struct batadv_unicast_packet *unicast_packet;
1811 struct batadv_coded_packet *coded_packet;
1812 struct batadv_nc_packet *nc_packet;
1813 struct ethhdr *ethhdr;
1814 int hdr_size = sizeof(*coded_packet);
1816 /* Check if network coding is enabled */
1817 if (!atomic_read(&bat_priv->network_coding))
1820 /* Make sure we can access (and remove) header */
1821 if (unlikely(!pskb_may_pull(skb, hdr_size)))
1824 coded_packet = (struct batadv_coded_packet *)skb->data;
1825 ethhdr = eth_hdr(skb);
1827 /* Verify frame is destined for us */
1828 if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1829 !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1832 /* Update stat counter */
1833 if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1834 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1836 nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1839 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1843 /* Make skb's linear, because decoding accesses the entire buffer */
1844 if (skb_linearize(skb) < 0)
1845 goto free_nc_packet;
1847 if (skb_linearize(nc_packet->skb) < 0)
1848 goto free_nc_packet;
1850 /* Decode the packet */
1851 unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1852 if (!unicast_packet) {
1853 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1854 goto free_nc_packet;
1857 /* Mark packet as decoded to do correct recoding when forwarding */
1858 BATADV_SKB_CB(skb)->decoded = true;
1859 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1860 batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1861 skb->len + ETH_HLEN);
1862 return batadv_recv_unicast_packet(skb, recv_if);
1865 batadv_nc_packet_free(nc_packet, true);
1873 * batadv_nc_mesh_free() - clean up network coding memory
1874 * @bat_priv: the bat priv with all the soft interface information
1876 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1878 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1879 batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1880 cancel_delayed_work_sync(&bat_priv->nc.work);
1882 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1883 batadv_hash_destroy(bat_priv->nc.coding_hash);
1884 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1885 batadv_hash_destroy(bat_priv->nc.decoding_hash);
1888 #ifdef CONFIG_BATMAN_ADV_DEBUGFS
1890 * batadv_nc_nodes_seq_print_text() - print the nc node information
1891 * @seq: seq file to print on
1896 int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
1898 struct net_device *net_dev = (struct net_device *)seq->private;
1899 struct batadv_priv *bat_priv = netdev_priv(net_dev);
1900 struct batadv_hashtable *hash = bat_priv->orig_hash;
1901 struct batadv_hard_iface *primary_if;
1902 struct hlist_head *head;
1903 struct batadv_orig_node *orig_node;
1904 struct batadv_nc_node *nc_node;
1907 primary_if = batadv_seq_print_text_primary_if_get(seq);
1911 /* Traverse list of originators */
1912 for (i = 0; i < hash->size; i++) {
1913 head = &hash->table[i];
1915 /* For each orig_node in this bin */
1917 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1918 /* no need to print the orig node if it does not have
1919 * network coding neighbors
1921 if (list_empty(&orig_node->in_coding_list) &&
1922 list_empty(&orig_node->out_coding_list))
1925 seq_printf(seq, "Node: %pM\n", orig_node->orig);
1927 seq_puts(seq, " Ingoing: ");
1928 /* For each in_nc_node to this orig_node */
1929 list_for_each_entry_rcu(nc_node,
1930 &orig_node->in_coding_list,
1932 seq_printf(seq, "%pM ",
1934 seq_puts(seq, "\n Outgoing: ");
1935 /* For out_nc_node to this orig_node */
1936 list_for_each_entry_rcu(nc_node,
1937 &orig_node->out_coding_list,
1939 seq_printf(seq, "%pM ",
1941 seq_puts(seq, "\n\n");
1948 batadv_hardif_put(primary_if);
1953 * batadv_nc_init_debugfs() - create nc folder and related files in debugfs
1954 * @bat_priv: the bat priv with all the soft interface information
1956 void batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
1958 struct dentry *nc_dir;
1960 nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
1962 debugfs_create_u8("min_tq", 0644, nc_dir, &bat_priv->nc.min_tq);
1964 debugfs_create_u32("max_fwd_delay", 0644, nc_dir,
1965 &bat_priv->nc.max_fwd_delay);
1967 debugfs_create_u32("max_buffer_time", 0644, nc_dir,
1968 &bat_priv->nc.max_buffer_time);