1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2012-2019 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/printk.h>
30 #include <linux/random.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 house keeping
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)
161 batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
162 &batadv_nc_decoding_hash_lock_class_key);
164 INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
165 batadv_nc_start_timer(bat_priv);
167 batadv_tvlv_handler_register(bat_priv, batadv_nc_tvlv_ogm_handler_v1,
168 NULL, BATADV_TVLV_NC, 1,
169 BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
170 batadv_nc_tvlv_container_update(bat_priv);
178 * batadv_nc_init_bat_priv() - initialise the nc specific bat_priv variables
179 * @bat_priv: the bat priv with all the soft interface information
181 void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
183 atomic_set(&bat_priv->network_coding, 0);
184 bat_priv->nc.min_tq = 200;
185 bat_priv->nc.max_fwd_delay = 10;
186 bat_priv->nc.max_buffer_time = 200;
190 * batadv_nc_init_orig() - initialise the nc fields of an orig_node
191 * @orig_node: the orig_node which is going to be initialised
193 void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
195 INIT_LIST_HEAD(&orig_node->in_coding_list);
196 INIT_LIST_HEAD(&orig_node->out_coding_list);
197 spin_lock_init(&orig_node->in_coding_list_lock);
198 spin_lock_init(&orig_node->out_coding_list_lock);
202 * batadv_nc_node_release() - release nc_node from lists and queue for free
203 * after rcu grace period
204 * @ref: kref pointer of the nc_node
206 static void batadv_nc_node_release(struct kref *ref)
208 struct batadv_nc_node *nc_node;
210 nc_node = container_of(ref, struct batadv_nc_node, refcount);
212 batadv_orig_node_put(nc_node->orig_node);
213 kfree_rcu(nc_node, rcu);
217 * batadv_nc_node_put() - decrement the nc_node refcounter and possibly
219 * @nc_node: nc_node to be free'd
221 static void batadv_nc_node_put(struct batadv_nc_node *nc_node)
223 kref_put(&nc_node->refcount, batadv_nc_node_release);
227 * batadv_nc_path_release() - release nc_path from lists and queue for free
228 * after rcu grace period
229 * @ref: kref pointer of the nc_path
231 static void batadv_nc_path_release(struct kref *ref)
233 struct batadv_nc_path *nc_path;
235 nc_path = container_of(ref, struct batadv_nc_path, refcount);
237 kfree_rcu(nc_path, rcu);
241 * batadv_nc_path_put() - decrement the nc_path refcounter and possibly
243 * @nc_path: nc_path to be free'd
245 static void batadv_nc_path_put(struct batadv_nc_path *nc_path)
247 kref_put(&nc_path->refcount, batadv_nc_path_release);
251 * batadv_nc_packet_free() - frees nc packet
252 * @nc_packet: the nc packet to free
253 * @dropped: whether the packet is freed because is is dropped
255 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet,
259 kfree_skb(nc_packet->skb);
261 consume_skb(nc_packet->skb);
263 batadv_nc_path_put(nc_packet->nc_path);
268 * batadv_nc_to_purge_nc_node() - checks whether an nc node has to be purged
269 * @bat_priv: the bat priv with all the soft interface information
270 * @nc_node: the nc node to check
272 * Return: true if the entry has to be purged now, false otherwise
274 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
275 struct batadv_nc_node *nc_node)
277 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
280 return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
284 * batadv_nc_to_purge_nc_path_coding() - checks whether an nc path has timed out
285 * @bat_priv: the bat priv with all the soft interface information
286 * @nc_path: the nc path to check
288 * Return: true if the entry has to be purged now, false otherwise
290 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
291 struct batadv_nc_path *nc_path)
293 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
296 /* purge the path when no packets has been added for 10 times the
299 return batadv_has_timed_out(nc_path->last_valid,
300 bat_priv->nc.max_fwd_delay * 10);
304 * batadv_nc_to_purge_nc_path_decoding() - checks whether an nc path has timed
306 * @bat_priv: the bat priv with all the soft interface information
307 * @nc_path: the nc path to check
309 * Return: true if the entry has to be purged now, false otherwise
311 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
312 struct batadv_nc_path *nc_path)
314 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
317 /* purge the path when no packets has been added for 10 times the
320 return batadv_has_timed_out(nc_path->last_valid,
321 bat_priv->nc.max_buffer_time * 10);
325 * batadv_nc_purge_orig_nc_nodes() - go through list of nc nodes and purge stale
327 * @bat_priv: the bat priv with all the soft interface information
328 * @list: list of nc nodes
329 * @lock: nc node list lock
330 * @to_purge: function in charge to decide whether an entry has to be purged or
331 * not. This function takes the nc node as argument and has to return
332 * a boolean value: true if the entry has to be deleted, false
336 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
337 struct list_head *list,
339 bool (*to_purge)(struct batadv_priv *,
340 struct batadv_nc_node *))
342 struct batadv_nc_node *nc_node, *nc_node_tmp;
344 /* For each nc_node in list */
346 list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
347 /* if an helper function has been passed as parameter,
348 * ask it if the entry has to be purged or not
350 if (to_purge && !to_purge(bat_priv, nc_node))
353 batadv_dbg(BATADV_DBG_NC, bat_priv,
354 "Removing nc_node %pM -> %pM\n",
355 nc_node->addr, nc_node->orig_node->orig);
356 list_del_rcu(&nc_node->list);
357 batadv_nc_node_put(nc_node);
359 spin_unlock_bh(lock);
363 * batadv_nc_purge_orig() - purges all nc node data attached of the given
365 * @bat_priv: the bat priv with all the soft interface information
366 * @orig_node: orig_node with the nc node entries to be purged
367 * @to_purge: function in charge to decide whether an entry has to be purged or
368 * not. This function takes the nc node as argument and has to return
369 * a boolean value: true is the entry has to be deleted, false
372 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
373 struct batadv_orig_node *orig_node,
374 bool (*to_purge)(struct batadv_priv *,
375 struct batadv_nc_node *))
377 /* Check ingoing nc_node's of this orig_node */
378 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
379 &orig_node->in_coding_list_lock,
382 /* Check outgoing nc_node's of this orig_node */
383 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
384 &orig_node->out_coding_list_lock,
389 * batadv_nc_purge_orig_hash() - traverse entire originator hash to check if
390 * they have timed out nc nodes
391 * @bat_priv: the bat priv with all the soft interface information
393 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
395 struct batadv_hashtable *hash = bat_priv->orig_hash;
396 struct hlist_head *head;
397 struct batadv_orig_node *orig_node;
403 /* For each orig_node */
404 for (i = 0; i < hash->size; i++) {
405 head = &hash->table[i];
408 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
409 batadv_nc_purge_orig(bat_priv, orig_node,
410 batadv_nc_to_purge_nc_node);
416 * batadv_nc_purge_paths() - traverse all nc paths part of the hash and remove
418 * @bat_priv: the bat priv with all the soft interface information
419 * @hash: hash table containing the nc paths to check
420 * @to_purge: function in charge to decide whether an entry has to be purged or
421 * not. This function takes the nc node as argument and has to return
422 * a boolean value: true is the entry has to be deleted, false
425 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
426 struct batadv_hashtable *hash,
427 bool (*to_purge)(struct batadv_priv *,
428 struct batadv_nc_path *))
430 struct hlist_head *head;
431 struct hlist_node *node_tmp;
432 struct batadv_nc_path *nc_path;
433 spinlock_t *lock; /* Protects lists in hash */
436 for (i = 0; i < hash->size; i++) {
437 head = &hash->table[i];
438 lock = &hash->list_locks[i];
440 /* For each nc_path in this bin */
442 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
443 /* if an helper function has been passed as parameter,
444 * ask it if the entry has to be purged or not
446 if (to_purge && !to_purge(bat_priv, nc_path))
449 /* purging an non-empty nc_path should never happen, but
450 * is observed under high CPU load. Delay the purging
451 * until next iteration to allow the packet_list to be
454 if (!unlikely(list_empty(&nc_path->packet_list))) {
455 net_ratelimited_function(printk,
457 "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
463 /* nc_path is unused, so remove it */
464 batadv_dbg(BATADV_DBG_NC, bat_priv,
465 "Remove nc_path %pM -> %pM\n",
466 nc_path->prev_hop, nc_path->next_hop);
467 hlist_del_rcu(&nc_path->hash_entry);
468 batadv_nc_path_put(nc_path);
470 spin_unlock_bh(lock);
475 * batadv_nc_hash_key_gen() - computes the nc_path hash key
476 * @key: buffer to hold the final hash key
477 * @src: source ethernet mac address going into the hash key
478 * @dst: destination ethernet mac address going into the hash key
480 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
483 memcpy(key->prev_hop, src, sizeof(key->prev_hop));
484 memcpy(key->next_hop, dst, sizeof(key->next_hop));
488 * batadv_nc_hash_choose() - compute the hash value for an nc path
489 * @data: data to hash
490 * @size: size of the hash table
492 * Return: the selected index in the hash table for the given data.
494 static u32 batadv_nc_hash_choose(const void *data, u32 size)
496 const struct batadv_nc_path *nc_path = data;
499 hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
500 hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
506 * batadv_nc_hash_compare() - comparing function used in the network coding hash
508 * @node: node in the local table
509 * @data2: second object to compare the node to
511 * Return: true if the two entry are the same, false otherwise
513 static bool batadv_nc_hash_compare(const struct hlist_node *node,
516 const struct batadv_nc_path *nc_path1, *nc_path2;
518 nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
521 /* Return 1 if the two keys are identical */
522 if (!batadv_compare_eth(nc_path1->prev_hop, nc_path2->prev_hop))
525 if (!batadv_compare_eth(nc_path1->next_hop, nc_path2->next_hop))
532 * batadv_nc_hash_find() - search for an existing nc path and return it
533 * @hash: hash table containing the nc path
536 * Return: the nc_path if found, NULL otherwise.
538 static struct batadv_nc_path *
539 batadv_nc_hash_find(struct batadv_hashtable *hash,
542 struct hlist_head *head;
543 struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
549 index = batadv_nc_hash_choose(data, hash->size);
550 head = &hash->table[index];
553 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
554 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
557 if (!kref_get_unless_zero(&nc_path->refcount))
560 nc_path_tmp = nc_path;
569 * batadv_nc_send_packet() - send non-coded packet and free nc_packet struct
570 * @nc_packet: the nc packet to send
572 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
574 batadv_send_unicast_skb(nc_packet->skb, nc_packet->neigh_node);
575 nc_packet->skb = NULL;
576 batadv_nc_packet_free(nc_packet, false);
580 * batadv_nc_sniffed_purge() - Checks timestamp of given sniffed nc_packet.
581 * @bat_priv: the bat priv with all the soft interface information
582 * @nc_path: the nc path the packet belongs to
583 * @nc_packet: the nc packet to be checked
585 * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
586 * timeout. If so, the packet is no longer kept and the entry deleted from the
587 * queue. Has to be called with the appropriate locks.
589 * Return: false as soon as the entry in the fifo queue has not been timed out
590 * yet and true otherwise.
592 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
593 struct batadv_nc_path *nc_path,
594 struct batadv_nc_packet *nc_packet)
596 unsigned long timeout = bat_priv->nc.max_buffer_time;
599 lockdep_assert_held(&nc_path->packet_list_lock);
601 /* Packets are added to tail, so the remaining packets did not time
602 * out and we can stop processing the current queue
604 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
605 !batadv_has_timed_out(nc_packet->timestamp, timeout))
608 /* purge nc packet */
609 list_del(&nc_packet->list);
610 batadv_nc_packet_free(nc_packet, true);
619 * batadv_nc_fwd_flush() - Checks the timestamp of the given nc packet.
620 * @bat_priv: the bat priv with all the soft interface information
621 * @nc_path: the nc path the packet belongs to
622 * @nc_packet: the nc packet to be checked
624 * Checks whether the given nc packet has hit its forward timeout. If so, the
625 * packet is no longer delayed, immediately sent and the entry deleted from the
626 * queue. Has to be called with the appropriate locks.
628 * Return: false as soon as the entry in the fifo queue has not been timed out
629 * yet and true otherwise.
631 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
632 struct batadv_nc_path *nc_path,
633 struct batadv_nc_packet *nc_packet)
635 unsigned long timeout = bat_priv->nc.max_fwd_delay;
637 lockdep_assert_held(&nc_path->packet_list_lock);
639 /* Packets are added to tail, so the remaining packets did not time
640 * out and we can stop processing the current queue
642 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
643 !batadv_has_timed_out(nc_packet->timestamp, timeout))
647 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
648 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
649 nc_packet->skb->len + ETH_HLEN);
650 list_del(&nc_packet->list);
651 batadv_nc_send_packet(nc_packet);
657 * batadv_nc_process_nc_paths() - traverse given nc packet pool and free timed
659 * @bat_priv: the bat priv with all the soft interface information
660 * @hash: to be processed hash table
661 * @process_fn: Function called to process given nc packet. Should return true
662 * to encourage this function to proceed with the next packet.
663 * Otherwise the rest of the current queue is skipped.
666 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
667 struct batadv_hashtable *hash,
668 bool (*process_fn)(struct batadv_priv *,
669 struct batadv_nc_path *,
670 struct batadv_nc_packet *))
672 struct hlist_head *head;
673 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
674 struct batadv_nc_path *nc_path;
681 /* Loop hash table bins */
682 for (i = 0; i < hash->size; i++) {
683 head = &hash->table[i];
685 /* Loop coding paths */
687 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
689 spin_lock_bh(&nc_path->packet_list_lock);
690 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
691 &nc_path->packet_list, list) {
692 ret = process_fn(bat_priv, nc_path, nc_packet);
696 spin_unlock_bh(&nc_path->packet_list_lock);
703 * batadv_nc_worker() - periodic task for house keeping related to network
705 * @work: kernel work struct
707 static void batadv_nc_worker(struct work_struct *work)
709 struct delayed_work *delayed_work;
710 struct batadv_priv_nc *priv_nc;
711 struct batadv_priv *bat_priv;
712 unsigned long timeout;
714 delayed_work = to_delayed_work(work);
715 priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
716 bat_priv = container_of(priv_nc, struct batadv_priv, nc);
718 batadv_nc_purge_orig_hash(bat_priv);
719 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
720 batadv_nc_to_purge_nc_path_coding);
721 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
722 batadv_nc_to_purge_nc_path_decoding);
724 timeout = bat_priv->nc.max_fwd_delay;
726 if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
727 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
728 batadv_nc_fwd_flush);
729 bat_priv->nc.timestamp_fwd_flush = jiffies;
732 if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
733 bat_priv->nc.max_buffer_time)) {
734 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
735 batadv_nc_sniffed_purge);
736 bat_priv->nc.timestamp_sniffed_purge = jiffies;
739 /* Schedule a new check */
740 batadv_nc_start_timer(bat_priv);
744 * batadv_can_nc_with_orig() - checks whether the given orig node is suitable
746 * @bat_priv: the bat priv with all the soft interface information
747 * @orig_node: neighboring orig node which may be used as nc candidate
748 * @ogm_packet: incoming ogm packet also used for the checks
751 * 1) The OGM must have the most recent sequence number.
752 * 2) The TTL must be decremented by one and only one.
753 * 3) The OGM must be received from the first hop from orig_node.
754 * 4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
756 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
757 struct batadv_orig_node *orig_node,
758 struct batadv_ogm_packet *ogm_packet)
760 struct batadv_orig_ifinfo *orig_ifinfo;
764 orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
768 last_ttl = orig_ifinfo->last_ttl;
769 last_real_seqno = orig_ifinfo->last_real_seqno;
770 batadv_orig_ifinfo_put(orig_ifinfo);
772 if (last_real_seqno != ntohl(ogm_packet->seqno))
774 if (last_ttl != ogm_packet->ttl + 1)
776 if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
778 if (ogm_packet->tq < bat_priv->nc.min_tq)
785 * batadv_nc_find_nc_node() - search for an existing nc node and return it
786 * @orig_node: orig node originating the ogm packet
787 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
788 * (can be equal to orig_node)
789 * @in_coding: traverse incoming or outgoing network coding list
791 * Return: the nc_node if found, NULL otherwise.
793 static struct batadv_nc_node *
794 batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
795 struct batadv_orig_node *orig_neigh_node,
798 struct batadv_nc_node *nc_node, *nc_node_out = NULL;
799 struct list_head *list;
802 list = &orig_neigh_node->in_coding_list;
804 list = &orig_neigh_node->out_coding_list;
806 /* Traverse list of nc_nodes to orig_node */
808 list_for_each_entry_rcu(nc_node, list, list) {
809 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
812 if (!kref_get_unless_zero(&nc_node->refcount))
816 nc_node_out = nc_node;
825 * batadv_nc_get_nc_node() - retrieves an nc node or creates the entry if it was
827 * @bat_priv: the bat priv with all the soft interface information
828 * @orig_node: orig node originating the ogm packet
829 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
830 * (can be equal to orig_node)
831 * @in_coding: traverse incoming or outgoing network coding list
833 * Return: the nc_node if found or created, NULL in case of an error.
835 static struct batadv_nc_node *
836 batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
837 struct batadv_orig_node *orig_node,
838 struct batadv_orig_node *orig_neigh_node,
841 struct batadv_nc_node *nc_node;
842 spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
843 struct list_head *list;
845 /* Select ingoing or outgoing coding node */
847 lock = &orig_neigh_node->in_coding_list_lock;
848 list = &orig_neigh_node->in_coding_list;
850 lock = &orig_neigh_node->out_coding_list_lock;
851 list = &orig_neigh_node->out_coding_list;
856 /* Check if nc_node is already added */
857 nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
863 nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
867 /* Initialize nc_node */
868 INIT_LIST_HEAD(&nc_node->list);
869 kref_init(&nc_node->refcount);
870 ether_addr_copy(nc_node->addr, orig_node->orig);
871 kref_get(&orig_neigh_node->refcount);
872 nc_node->orig_node = orig_neigh_node;
874 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
875 nc_node->addr, nc_node->orig_node->orig);
877 /* Add nc_node to orig_node */
878 kref_get(&nc_node->refcount);
879 list_add_tail_rcu(&nc_node->list, list);
882 spin_unlock_bh(lock);
888 * batadv_nc_update_nc_node() - updates stored incoming and outgoing nc node
889 * structs (best called on incoming OGMs)
890 * @bat_priv: the bat priv with all the soft interface information
891 * @orig_node: orig node originating the ogm packet
892 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
893 * (can be equal to orig_node)
894 * @ogm_packet: incoming ogm packet
895 * @is_single_hop_neigh: orig_node is a single hop neighbor
897 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
898 struct batadv_orig_node *orig_node,
899 struct batadv_orig_node *orig_neigh_node,
900 struct batadv_ogm_packet *ogm_packet,
901 int is_single_hop_neigh)
903 struct batadv_nc_node *in_nc_node = NULL;
904 struct batadv_nc_node *out_nc_node = NULL;
906 /* Check if network coding is enabled */
907 if (!atomic_read(&bat_priv->network_coding))
910 /* check if orig node is network coding enabled */
911 if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
914 /* accept ogms from 'good' neighbors and single hop neighbors */
915 if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
916 !is_single_hop_neigh)
919 /* Add orig_node as in_nc_node on hop */
920 in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
921 orig_neigh_node, true);
925 in_nc_node->last_seen = jiffies;
927 /* Add hop as out_nc_node on orig_node */
928 out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
933 out_nc_node->last_seen = jiffies;
937 batadv_nc_node_put(in_nc_node);
939 batadv_nc_node_put(out_nc_node);
943 * batadv_nc_get_path() - get existing nc_path or allocate a new one
944 * @bat_priv: the bat priv with all the soft interface information
945 * @hash: hash table containing the nc path
946 * @src: ethernet source address - first half of the nc path search key
947 * @dst: ethernet destination address - second half of the nc path search key
949 * Return: pointer to nc_path if the path was found or created, returns NULL
952 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
953 struct batadv_hashtable *hash,
958 struct batadv_nc_path *nc_path, nc_path_key;
960 batadv_nc_hash_key_gen(&nc_path_key, src, dst);
962 /* Search for existing nc_path */
963 nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
966 /* Set timestamp to delay removal of nc_path */
967 nc_path->last_valid = jiffies;
971 /* No existing nc_path was found; create a new */
972 nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
977 /* Initialize nc_path */
978 INIT_LIST_HEAD(&nc_path->packet_list);
979 spin_lock_init(&nc_path->packet_list_lock);
980 kref_init(&nc_path->refcount);
981 nc_path->last_valid = jiffies;
982 ether_addr_copy(nc_path->next_hop, dst);
983 ether_addr_copy(nc_path->prev_hop, src);
985 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
989 /* Add nc_path to hash table */
990 kref_get(&nc_path->refcount);
991 hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
992 batadv_nc_hash_choose, &nc_path_key,
993 &nc_path->hash_entry);
995 if (hash_added < 0) {
1004 * batadv_nc_random_weight_tq() - scale the receivers TQ-value to avoid unfair
1005 * selection of a receiver with slightly lower TQ than the other
1006 * @tq: to be weighted tq value
1008 * Return: scaled tq value
1010 static u8 batadv_nc_random_weight_tq(u8 tq)
1012 u8 rand_val, rand_tq;
1014 get_random_bytes(&rand_val, sizeof(rand_val));
1016 /* randomize the estimated packet loss (max TQ - estimated TQ) */
1017 rand_tq = rand_val * (BATADV_TQ_MAX_VALUE - tq);
1019 /* normalize the randomized packet loss */
1020 rand_tq /= BATADV_TQ_MAX_VALUE;
1022 /* convert to (randomized) estimated tq again */
1023 return BATADV_TQ_MAX_VALUE - rand_tq;
1027 * batadv_nc_memxor() - XOR destination with source
1028 * @dst: byte array to XOR into
1029 * @src: byte array to XOR from
1030 * @len: length of destination array
1032 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
1036 for (i = 0; i < len; ++i)
1041 * batadv_nc_code_packets() - code a received unicast_packet with an nc packet
1042 * into a coded_packet and send it
1043 * @bat_priv: the bat priv with all the soft interface information
1044 * @skb: data skb to forward
1045 * @ethhdr: pointer to the ethernet header inside the skb
1046 * @nc_packet: structure containing the packet to the skb can be coded with
1047 * @neigh_node: next hop to forward packet to
1049 * Return: true if both packets are consumed, false otherwise.
1051 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1052 struct sk_buff *skb,
1053 struct ethhdr *ethhdr,
1054 struct batadv_nc_packet *nc_packet,
1055 struct batadv_neigh_node *neigh_node)
1057 u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1058 struct sk_buff *skb_dest, *skb_src;
1059 struct batadv_unicast_packet *packet1;
1060 struct batadv_unicast_packet *packet2;
1061 struct batadv_coded_packet *coded_packet;
1062 struct batadv_neigh_node *neigh_tmp, *router_neigh, *first_dest;
1063 struct batadv_neigh_node *router_coding = NULL, *second_dest;
1064 struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1065 struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1066 u8 *first_source, *second_source;
1067 __be32 packet_id1, packet_id2;
1071 int unicast_size = sizeof(*packet1);
1072 int coded_size = sizeof(*coded_packet);
1073 int header_add = coded_size - unicast_size;
1075 /* TODO: do we need to consider the outgoing interface for
1078 router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1083 router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1085 if (!router_neigh_ifinfo)
1088 neigh_tmp = nc_packet->neigh_node;
1089 router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1094 router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1096 if (!router_coding_ifinfo)
1099 tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1100 tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1101 tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1102 tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1104 /* Select one destination for the MAC-header dst-field based on
1105 * weighted TQ-values.
1107 if (tq_weighted_neigh >= tq_weighted_coding) {
1108 /* Destination from nc_packet is selected for MAC-header */
1109 first_dest = nc_packet->neigh_node;
1110 first_source = nc_packet->nc_path->prev_hop;
1111 second_dest = neigh_node;
1112 second_source = ethhdr->h_source;
1113 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1114 packet2 = (struct batadv_unicast_packet *)skb->data;
1115 packet_id1 = nc_packet->packet_id;
1116 packet_id2 = batadv_skb_crc32(skb,
1117 skb->data + sizeof(*packet2));
1119 /* Destination for skb is selected for MAC-header */
1120 first_dest = neigh_node;
1121 first_source = ethhdr->h_source;
1122 second_dest = nc_packet->neigh_node;
1123 second_source = nc_packet->nc_path->prev_hop;
1124 packet1 = (struct batadv_unicast_packet *)skb->data;
1125 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1126 packet_id1 = batadv_skb_crc32(skb,
1127 skb->data + sizeof(*packet1));
1128 packet_id2 = nc_packet->packet_id;
1131 /* Instead of zero padding the smallest data buffer, we
1132 * code into the largest.
1134 if (skb->len <= nc_packet->skb->len) {
1135 skb_dest = nc_packet->skb;
1139 skb_src = nc_packet->skb;
1142 /* coding_len is used when decoding the packet shorter packet */
1143 coding_len = skb_src->len - unicast_size;
1145 if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1148 skb_push(skb_dest, header_add);
1150 coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1151 skb_reset_mac_header(skb_dest);
1153 coded_packet->packet_type = BATADV_CODED;
1154 coded_packet->version = BATADV_COMPAT_VERSION;
1155 coded_packet->ttl = packet1->ttl;
1157 /* Info about first unicast packet */
1158 ether_addr_copy(coded_packet->first_source, first_source);
1159 ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1160 coded_packet->first_crc = packet_id1;
1161 coded_packet->first_ttvn = packet1->ttvn;
1163 /* Info about second unicast packet */
1164 ether_addr_copy(coded_packet->second_dest, second_dest->addr);
1165 ether_addr_copy(coded_packet->second_source, second_source);
1166 ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1167 coded_packet->second_crc = packet_id2;
1168 coded_packet->second_ttl = packet2->ttl;
1169 coded_packet->second_ttvn = packet2->ttvn;
1170 coded_packet->coded_len = htons(coding_len);
1172 /* This is where the magic happens: Code skb_src into skb_dest */
1173 batadv_nc_memxor(skb_dest->data + coded_size,
1174 skb_src->data + unicast_size, coding_len);
1176 /* Update counters accordingly */
1177 if (BATADV_SKB_CB(skb_src)->decoded &&
1178 BATADV_SKB_CB(skb_dest)->decoded) {
1179 /* Both packets are recoded */
1180 count = skb_src->len + ETH_HLEN;
1181 count += skb_dest->len + ETH_HLEN;
1182 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1183 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1184 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1185 !BATADV_SKB_CB(skb_dest)->decoded) {
1186 /* Both packets are newly coded */
1187 count = skb_src->len + ETH_HLEN;
1188 count += skb_dest->len + ETH_HLEN;
1189 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1190 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1191 } else if (BATADV_SKB_CB(skb_src)->decoded &&
1192 !BATADV_SKB_CB(skb_dest)->decoded) {
1193 /* skb_src recoded and skb_dest is newly coded */
1194 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1195 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1196 skb_src->len + ETH_HLEN);
1197 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1198 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1199 skb_dest->len + ETH_HLEN);
1200 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1201 BATADV_SKB_CB(skb_dest)->decoded) {
1202 /* skb_src is newly coded and skb_dest is recoded */
1203 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1204 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1205 skb_src->len + ETH_HLEN);
1206 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1207 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1208 skb_dest->len + ETH_HLEN);
1211 /* skb_src is now coded into skb_dest, so free it */
1212 consume_skb(skb_src);
1214 /* avoid duplicate free of skb from nc_packet */
1215 nc_packet->skb = NULL;
1216 batadv_nc_packet_free(nc_packet, false);
1218 /* Send the coded packet and return true */
1219 batadv_send_unicast_skb(skb_dest, first_dest);
1223 batadv_neigh_node_put(router_neigh);
1225 batadv_neigh_node_put(router_coding);
1226 if (router_neigh_ifinfo)
1227 batadv_neigh_ifinfo_put(router_neigh_ifinfo);
1228 if (router_coding_ifinfo)
1229 batadv_neigh_ifinfo_put(router_coding_ifinfo);
1234 * batadv_nc_skb_coding_possible() - true if a decoded skb is available at dst.
1235 * @skb: data skb to forward
1236 * @dst: destination mac address of the other skb to code with
1237 * @src: source mac address of skb
1239 * Whenever we network code a packet we have to check whether we received it in
1240 * a network coded form. If so, we may not be able to use it for coding because
1241 * some neighbors may also have received (overheard) the packet in the network
1242 * coded form without being able to decode it. It is hard to know which of the
1243 * neighboring nodes was able to decode the packet, therefore we can only
1244 * re-code the packet if the source of the previous encoded packet is involved.
1245 * Since the source encoded the packet we can be certain it has all necessary
1246 * decode information.
1248 * Return: true if coding of a decoded packet is allowed.
1250 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1252 if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1258 * batadv_nc_path_search() - Find the coding path matching in_nc_node and
1259 * out_nc_node to retrieve a buffered packet that can be used for coding.
1260 * @bat_priv: the bat priv with all the soft interface information
1261 * @in_nc_node: pointer to skb next hop's neighbor nc node
1262 * @out_nc_node: pointer to skb source's neighbor nc node
1263 * @skb: data skb to forward
1264 * @eth_dst: next hop mac address of skb
1266 * Return: true if coding of a decoded skb is allowed.
1268 static struct batadv_nc_packet *
1269 batadv_nc_path_search(struct batadv_priv *bat_priv,
1270 struct batadv_nc_node *in_nc_node,
1271 struct batadv_nc_node *out_nc_node,
1272 struct sk_buff *skb,
1275 struct batadv_nc_path *nc_path, nc_path_key;
1276 struct batadv_nc_packet *nc_packet_out = NULL;
1277 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1278 struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1284 /* Create almost path key */
1285 batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1287 idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1289 /* Check for coding opportunities in this nc_path */
1291 hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1292 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1295 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1298 spin_lock_bh(&nc_path->packet_list_lock);
1299 if (list_empty(&nc_path->packet_list)) {
1300 spin_unlock_bh(&nc_path->packet_list_lock);
1304 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1305 &nc_path->packet_list, list) {
1306 if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1311 /* Coding opportunity is found! */
1312 list_del(&nc_packet->list);
1313 nc_packet_out = nc_packet;
1317 spin_unlock_bh(&nc_path->packet_list_lock);
1322 return nc_packet_out;
1326 * batadv_nc_skb_src_search() - Loops through the list of neighoring nodes of
1327 * the skb's sender (may be equal to the originator).
1328 * @bat_priv: the bat priv with all the soft interface information
1329 * @skb: data skb to forward
1330 * @eth_dst: next hop mac address of skb
1331 * @eth_src: source mac address of skb
1332 * @in_nc_node: pointer to skb next hop's neighbor nc node
1334 * Return: an nc packet if a suitable coding packet was found, NULL otherwise.
1336 static struct batadv_nc_packet *
1337 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1338 struct sk_buff *skb,
1341 struct batadv_nc_node *in_nc_node)
1343 struct batadv_orig_node *orig_node;
1344 struct batadv_nc_node *out_nc_node;
1345 struct batadv_nc_packet *nc_packet = NULL;
1347 orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1352 list_for_each_entry_rcu(out_nc_node,
1353 &orig_node->out_coding_list, list) {
1354 /* Check if the skb is decoded and if recoding is possible */
1355 if (!batadv_nc_skb_coding_possible(skb,
1356 out_nc_node->addr, eth_src))
1359 /* Search for an opportunity in this nc_path */
1360 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1361 out_nc_node, skb, eth_dst);
1367 batadv_orig_node_put(orig_node);
1372 * batadv_nc_skb_store_before_coding() - set the ethernet src and dst of the
1373 * unicast skb before it is stored for use in later decoding
1374 * @bat_priv: the bat priv with all the soft interface information
1375 * @skb: data skb to store
1376 * @eth_dst_new: new destination mac address of skb
1378 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1379 struct sk_buff *skb,
1382 struct ethhdr *ethhdr;
1384 /* Copy skb header to change the mac header */
1385 skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1389 /* Set the mac header as if we actually sent the packet uncoded */
1390 ethhdr = eth_hdr(skb);
1391 ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1392 ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1394 /* Set data pointer to MAC header to mimic packets from our tx path */
1395 skb_push(skb, ETH_HLEN);
1397 /* Add the packet to the decoding packet pool */
1398 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1400 /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1407 * batadv_nc_skb_dst_search() - Loops through list of neighboring nodes to dst.
1408 * @skb: data skb to forward
1409 * @neigh_node: next hop to forward packet to
1410 * @ethhdr: pointer to the ethernet header inside the skb
1412 * Loops through list of neighboring nodes the next hop has a good connection to
1413 * (receives OGMs with a sufficient quality). We need to find a neighbor of our
1414 * next hop that potentially sent a packet which our next hop also received
1415 * (overheard) and has stored for later decoding.
1417 * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1419 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1420 struct batadv_neigh_node *neigh_node,
1421 struct ethhdr *ethhdr)
1423 struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1424 struct batadv_priv *bat_priv = netdev_priv(netdev);
1425 struct batadv_orig_node *orig_node = neigh_node->orig_node;
1426 struct batadv_nc_node *nc_node;
1427 struct batadv_nc_packet *nc_packet = NULL;
1430 list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1431 /* Search for coding opportunity with this in_nc_node */
1432 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1434 ethhdr->h_source, nc_node);
1436 /* Opportunity was found, so stop searching */
1445 /* Save packets for later decoding */
1446 batadv_nc_skb_store_before_coding(bat_priv, skb,
1448 batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1449 nc_packet->neigh_node->addr);
1451 /* Code and send packets */
1452 if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1456 /* out of mem ? Coding failed - we have to free the buffered packet
1457 * to avoid memleaks. The skb passed as argument will be dealt with
1458 * by the calling function.
1460 batadv_nc_send_packet(nc_packet);
1465 * batadv_nc_skb_add_to_path() - buffer skb for later encoding / decoding
1466 * @skb: skb to add to path
1467 * @nc_path: path to add skb to
1468 * @neigh_node: next hop to forward packet to
1469 * @packet_id: checksum to identify packet
1471 * Return: true if the packet was buffered or false in case of an error.
1473 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1474 struct batadv_nc_path *nc_path,
1475 struct batadv_neigh_node *neigh_node,
1478 struct batadv_nc_packet *nc_packet;
1480 nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1484 /* Initialize nc_packet */
1485 nc_packet->timestamp = jiffies;
1486 nc_packet->packet_id = packet_id;
1487 nc_packet->skb = skb;
1488 nc_packet->neigh_node = neigh_node;
1489 nc_packet->nc_path = nc_path;
1491 /* Add coding packet to list */
1492 spin_lock_bh(&nc_path->packet_list_lock);
1493 list_add_tail(&nc_packet->list, &nc_path->packet_list);
1494 spin_unlock_bh(&nc_path->packet_list_lock);
1500 * batadv_nc_skb_forward() - try to code a packet or add it to the coding packet
1502 * @skb: data skb to forward
1503 * @neigh_node: next hop to forward packet to
1505 * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1507 bool batadv_nc_skb_forward(struct sk_buff *skb,
1508 struct batadv_neigh_node *neigh_node)
1510 const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1511 struct batadv_priv *bat_priv = netdev_priv(netdev);
1512 struct batadv_unicast_packet *packet;
1513 struct batadv_nc_path *nc_path;
1514 struct ethhdr *ethhdr = eth_hdr(skb);
1518 /* Check if network coding is enabled */
1519 if (!atomic_read(&bat_priv->network_coding))
1522 /* We only handle unicast packets */
1523 payload = skb_network_header(skb);
1524 packet = (struct batadv_unicast_packet *)payload;
1525 if (packet->packet_type != BATADV_UNICAST)
1528 /* Try to find a coding opportunity and send the skb if one is found */
1529 if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1532 /* Find or create a nc_path for this src-dst pair */
1533 nc_path = batadv_nc_get_path(bat_priv,
1534 bat_priv->nc.coding_hash,
1541 /* Add skb to nc_path */
1542 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1543 if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1546 /* Packet is consumed */
1550 batadv_nc_path_put(nc_path);
1552 /* Packet is not consumed */
1557 * batadv_nc_skb_store_for_decoding() - save a clone of the skb which can be
1558 * used when decoding coded packets
1559 * @bat_priv: the bat priv with all the soft interface information
1560 * @skb: data skb to store
1562 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1563 struct sk_buff *skb)
1565 struct batadv_unicast_packet *packet;
1566 struct batadv_nc_path *nc_path;
1567 struct ethhdr *ethhdr = eth_hdr(skb);
1571 /* Check if network coding is enabled */
1572 if (!atomic_read(&bat_priv->network_coding))
1575 /* Check for supported packet type */
1576 payload = skb_network_header(skb);
1577 packet = (struct batadv_unicast_packet *)payload;
1578 if (packet->packet_type != BATADV_UNICAST)
1581 /* Find existing nc_path or create a new */
1582 nc_path = batadv_nc_get_path(bat_priv,
1583 bat_priv->nc.decoding_hash,
1590 /* Clone skb and adjust skb->data to point at batman header */
1591 skb = skb_clone(skb, GFP_ATOMIC);
1595 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1598 if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1601 /* Add skb to nc_path */
1602 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1603 if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1606 batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1612 batadv_nc_path_put(nc_path);
1618 * batadv_nc_skb_store_sniffed_unicast() - check if a received unicast packet
1619 * should be saved in the decoding buffer and, if so, store it there
1620 * @bat_priv: the bat priv with all the soft interface information
1621 * @skb: unicast skb to store
1623 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1624 struct sk_buff *skb)
1626 struct ethhdr *ethhdr = eth_hdr(skb);
1628 if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1631 /* Set data pointer to MAC header to mimic packets from our tx path */
1632 skb_push(skb, ETH_HLEN);
1634 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1638 * batadv_nc_skb_decode_packet() - decode given skb using the decode data stored
1640 * @bat_priv: the bat priv with all the soft interface information
1641 * @skb: unicast skb to decode
1642 * @nc_packet: decode data needed to decode the skb
1644 * Return: pointer to decoded unicast packet if the packet was decoded or NULL
1645 * in case of an error.
1647 static struct batadv_unicast_packet *
1648 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1649 struct batadv_nc_packet *nc_packet)
1651 const int h_size = sizeof(struct batadv_unicast_packet);
1652 const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1653 struct batadv_unicast_packet *unicast_packet;
1654 struct batadv_coded_packet coded_packet_tmp;
1655 struct ethhdr *ethhdr, ethhdr_tmp;
1656 u8 *orig_dest, ttl, ttvn;
1657 unsigned int coding_len;
1660 /* Save headers temporarily */
1661 memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1662 memcpy(ðhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1664 if (skb_cow(skb, 0) < 0)
1667 if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1670 /* Data points to batman header, so set mac header 14 bytes before
1671 * and network to data
1673 skb_set_mac_header(skb, -ETH_HLEN);
1674 skb_reset_network_header(skb);
1676 /* Reconstruct original mac header */
1677 ethhdr = eth_hdr(skb);
1678 *ethhdr = ethhdr_tmp;
1680 /* Select the correct unicast header information based on the location
1681 * of our mac address in the coded_packet header
1683 if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1684 /* If we are the second destination the packet was overheard,
1685 * so the Ethernet address must be copied to h_dest and
1686 * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1688 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1689 skb->pkt_type = PACKET_HOST;
1691 orig_dest = coded_packet_tmp.second_orig_dest;
1692 ttl = coded_packet_tmp.second_ttl;
1693 ttvn = coded_packet_tmp.second_ttvn;
1695 orig_dest = coded_packet_tmp.first_orig_dest;
1696 ttl = coded_packet_tmp.ttl;
1697 ttvn = coded_packet_tmp.first_ttvn;
1700 coding_len = ntohs(coded_packet_tmp.coded_len);
1702 if (coding_len > skb->len)
1705 /* Here the magic is reversed:
1706 * extract the missing packet from the received coded packet
1708 batadv_nc_memxor(skb->data + h_size,
1709 nc_packet->skb->data + h_size,
1712 /* Resize decoded skb if decoded with larger packet */
1713 if (nc_packet->skb->len > coding_len + h_size) {
1714 err = pskb_trim_rcsum(skb, coding_len + h_size);
1719 /* Create decoded unicast packet */
1720 unicast_packet = (struct batadv_unicast_packet *)skb->data;
1721 unicast_packet->packet_type = BATADV_UNICAST;
1722 unicast_packet->version = BATADV_COMPAT_VERSION;
1723 unicast_packet->ttl = ttl;
1724 ether_addr_copy(unicast_packet->dest, orig_dest);
1725 unicast_packet->ttvn = ttvn;
1727 batadv_nc_packet_free(nc_packet, false);
1728 return unicast_packet;
1732 * batadv_nc_find_decoding_packet() - search through buffered decoding data to
1733 * find the data needed to decode the coded packet
1734 * @bat_priv: the bat priv with all the soft interface information
1735 * @ethhdr: pointer to the ethernet header inside the coded packet
1736 * @coded: coded packet we try to find decode data for
1738 * Return: pointer to nc packet if the needed data was found or NULL otherwise.
1740 static struct batadv_nc_packet *
1741 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1742 struct ethhdr *ethhdr,
1743 struct batadv_coded_packet *coded)
1745 struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1746 struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1747 struct batadv_nc_path *nc_path, nc_path_key;
1755 /* Select the correct packet id based on the location of our mac-addr */
1756 dest = ethhdr->h_source;
1757 if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1758 source = coded->second_source;
1759 packet_id = coded->second_crc;
1761 source = coded->first_source;
1762 packet_id = coded->first_crc;
1765 batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1766 index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1768 /* Search for matching coding path */
1770 hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1771 /* Find matching nc_packet */
1772 spin_lock_bh(&nc_path->packet_list_lock);
1773 list_for_each_entry(tmp_nc_packet,
1774 &nc_path->packet_list, list) {
1775 if (packet_id == tmp_nc_packet->packet_id) {
1776 list_del(&tmp_nc_packet->list);
1778 nc_packet = tmp_nc_packet;
1782 spin_unlock_bh(&nc_path->packet_list_lock);
1790 batadv_dbg(BATADV_DBG_NC, bat_priv,
1791 "No decoding packet found for %u\n", packet_id);
1797 * batadv_nc_recv_coded_packet() - try to decode coded packet and enqueue the
1798 * resulting unicast packet
1799 * @skb: incoming coded packet
1800 * @recv_if: pointer to interface this packet was received on
1802 * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1805 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1806 struct batadv_hard_iface *recv_if)
1808 struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1809 struct batadv_unicast_packet *unicast_packet;
1810 struct batadv_coded_packet *coded_packet;
1811 struct batadv_nc_packet *nc_packet;
1812 struct ethhdr *ethhdr;
1813 int hdr_size = sizeof(*coded_packet);
1815 /* Check if network coding is enabled */
1816 if (!atomic_read(&bat_priv->network_coding))
1819 /* Make sure we can access (and remove) header */
1820 if (unlikely(!pskb_may_pull(skb, hdr_size)))
1823 coded_packet = (struct batadv_coded_packet *)skb->data;
1824 ethhdr = eth_hdr(skb);
1826 /* Verify frame is destined for us */
1827 if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1828 !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1831 /* Update stat counter */
1832 if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1833 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1835 nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1838 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1842 /* Make skb's linear, because decoding accesses the entire buffer */
1843 if (skb_linearize(skb) < 0)
1844 goto free_nc_packet;
1846 if (skb_linearize(nc_packet->skb) < 0)
1847 goto free_nc_packet;
1849 /* Decode the packet */
1850 unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1851 if (!unicast_packet) {
1852 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1853 goto free_nc_packet;
1856 /* Mark packet as decoded to do correct recoding when forwarding */
1857 BATADV_SKB_CB(skb)->decoded = true;
1858 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1859 batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1860 skb->len + ETH_HLEN);
1861 return batadv_recv_unicast_packet(skb, recv_if);
1864 batadv_nc_packet_free(nc_packet, true);
1872 * batadv_nc_mesh_free() - clean up network coding memory
1873 * @bat_priv: the bat priv with all the soft interface information
1875 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1877 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1878 batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1879 cancel_delayed_work_sync(&bat_priv->nc.work);
1881 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1882 batadv_hash_destroy(bat_priv->nc.coding_hash);
1883 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1884 batadv_hash_destroy(bat_priv->nc.decoding_hash);
1887 #ifdef CONFIG_BATMAN_ADV_DEBUGFS
1889 * batadv_nc_nodes_seq_print_text() - print the nc node information
1890 * @seq: seq file to print on
1895 int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
1897 struct net_device *net_dev = (struct net_device *)seq->private;
1898 struct batadv_priv *bat_priv = netdev_priv(net_dev);
1899 struct batadv_hashtable *hash = bat_priv->orig_hash;
1900 struct batadv_hard_iface *primary_if;
1901 struct hlist_head *head;
1902 struct batadv_orig_node *orig_node;
1903 struct batadv_nc_node *nc_node;
1906 primary_if = batadv_seq_print_text_primary_if_get(seq);
1910 /* Traverse list of originators */
1911 for (i = 0; i < hash->size; i++) {
1912 head = &hash->table[i];
1914 /* For each orig_node in this bin */
1916 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1917 /* no need to print the orig node if it does not have
1918 * network coding neighbors
1920 if (list_empty(&orig_node->in_coding_list) &&
1921 list_empty(&orig_node->out_coding_list))
1924 seq_printf(seq, "Node: %pM\n", orig_node->orig);
1926 seq_puts(seq, " Ingoing: ");
1927 /* For each in_nc_node to this orig_node */
1928 list_for_each_entry_rcu(nc_node,
1929 &orig_node->in_coding_list,
1931 seq_printf(seq, "%pM ",
1933 seq_puts(seq, "\n Outgoing: ");
1934 /* For out_nc_node to this orig_node */
1935 list_for_each_entry_rcu(nc_node,
1936 &orig_node->out_coding_list,
1938 seq_printf(seq, "%pM ",
1940 seq_puts(seq, "\n\n");
1947 batadv_hardif_put(primary_if);
1952 * batadv_nc_init_debugfs() - create nc folder and related files in debugfs
1953 * @bat_priv: the bat priv with all the soft interface information
1955 void batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
1957 struct dentry *nc_dir;
1959 nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
1961 debugfs_create_u8("min_tq", 0644, nc_dir, &bat_priv->nc.min_tq);
1963 debugfs_create_u32("max_fwd_delay", 0644, nc_dir,
1964 &bat_priv->nc.max_fwd_delay);
1966 debugfs_create_u32("max_buffer_time", 0644, nc_dir,
1967 &bat_priv->nc.max_buffer_time);