1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 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/errno.h>
15 #include <linux/etherdevice.h>
16 #include <linux/gfp.h>
17 #include <linux/if_ether.h>
18 #include <linux/if_packet.h>
19 #include <linux/init.h>
20 #include <linux/jhash.h>
21 #include <linux/jiffies.h>
22 #include <linux/kernel.h>
23 #include <linux/kref.h>
24 #include <linux/list.h>
25 #include <linux/lockdep.h>
26 #include <linux/net.h>
27 #include <linux/netdevice.h>
28 #include <linux/prandom.h>
29 #include <linux/printk.h>
30 #include <linux/rculist.h>
31 #include <linux/rcupdate.h>
32 #include <linux/skbuff.h>
33 #include <linux/slab.h>
34 #include <linux/spinlock.h>
35 #include <linux/stddef.h>
36 #include <linux/string.h>
37 #include <linux/workqueue.h>
38 #include <uapi/linux/batadv_packet.h>
42 #include "originator.h"
47 static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
48 static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
50 static void batadv_nc_worker(struct work_struct *work);
51 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
52 struct batadv_hard_iface *recv_if);
55 * batadv_nc_init() - one-time initialization for network coding
57 * Return: 0 on success or negative error number in case of failure
59 int __init batadv_nc_init(void)
63 /* Register our packet type */
64 ret = batadv_recv_handler_register(BATADV_CODED,
65 batadv_nc_recv_coded_packet);
71 * batadv_nc_start_timer() - initialise the nc periodic worker
72 * @bat_priv: the bat priv with all the soft interface information
74 static void batadv_nc_start_timer(struct batadv_priv *bat_priv)
76 queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work,
77 msecs_to_jiffies(10));
81 * batadv_nc_tvlv_container_update() - update the network coding tvlv container
82 * after network coding setting change
83 * @bat_priv: the bat priv with all the soft interface information
85 static void batadv_nc_tvlv_container_update(struct batadv_priv *bat_priv)
89 nc_mode = atomic_read(&bat_priv->network_coding);
93 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
96 batadv_tvlv_container_register(bat_priv, BATADV_TVLV_NC, 1,
103 * batadv_nc_status_update() - update the network coding tvlv container after
104 * network coding setting change
105 * @net_dev: the soft interface net device
107 void batadv_nc_status_update(struct net_device *net_dev)
109 struct batadv_priv *bat_priv = netdev_priv(net_dev);
111 batadv_nc_tvlv_container_update(bat_priv);
115 * batadv_nc_tvlv_ogm_handler_v1() - process incoming nc tvlv container
116 * @bat_priv: the bat priv with all the soft interface information
117 * @orig: the orig_node of the ogm
118 * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
119 * @tvlv_value: tvlv buffer containing the gateway data
120 * @tvlv_value_len: tvlv buffer length
122 static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
123 struct batadv_orig_node *orig,
125 void *tvlv_value, u16 tvlv_value_len)
127 if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
128 clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
130 set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
134 * batadv_nc_mesh_init() - initialise coding hash table and start housekeeping
135 * @bat_priv: the bat priv with all the soft interface information
137 * Return: 0 on success or negative error number in case of failure
139 int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
141 bat_priv->nc.timestamp_fwd_flush = jiffies;
142 bat_priv->nc.timestamp_sniffed_purge = jiffies;
144 if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
147 bat_priv->nc.coding_hash = batadv_hash_new(128);
148 if (!bat_priv->nc.coding_hash)
151 batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
152 &batadv_nc_coding_hash_lock_class_key);
154 bat_priv->nc.decoding_hash = batadv_hash_new(128);
155 if (!bat_priv->nc.decoding_hash) {
156 batadv_hash_destroy(bat_priv->nc.coding_hash);
160 batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
161 &batadv_nc_decoding_hash_lock_class_key);
163 INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
164 batadv_nc_start_timer(bat_priv);
166 batadv_tvlv_handler_register(bat_priv, batadv_nc_tvlv_ogm_handler_v1,
167 NULL, BATADV_TVLV_NC, 1,
168 BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
169 batadv_nc_tvlv_container_update(bat_priv);
177 * batadv_nc_init_bat_priv() - initialise the nc specific bat_priv variables
178 * @bat_priv: the bat priv with all the soft interface information
180 void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
182 atomic_set(&bat_priv->network_coding, 0);
183 bat_priv->nc.min_tq = 200;
184 bat_priv->nc.max_fwd_delay = 10;
185 bat_priv->nc.max_buffer_time = 200;
189 * batadv_nc_init_orig() - initialise the nc fields of an orig_node
190 * @orig_node: the orig_node which is going to be initialised
192 void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
194 INIT_LIST_HEAD(&orig_node->in_coding_list);
195 INIT_LIST_HEAD(&orig_node->out_coding_list);
196 spin_lock_init(&orig_node->in_coding_list_lock);
197 spin_lock_init(&orig_node->out_coding_list_lock);
201 * batadv_nc_node_release() - release nc_node from lists and queue for free
202 * after rcu grace period
203 * @ref: kref pointer of the nc_node
205 static void batadv_nc_node_release(struct kref *ref)
207 struct batadv_nc_node *nc_node;
209 nc_node = container_of(ref, struct batadv_nc_node, refcount);
211 batadv_orig_node_put(nc_node->orig_node);
212 kfree_rcu(nc_node, rcu);
216 * batadv_nc_node_put() - decrement the nc_node refcounter and possibly
218 * @nc_node: nc_node to be free'd
220 static void batadv_nc_node_put(struct batadv_nc_node *nc_node)
225 kref_put(&nc_node->refcount, batadv_nc_node_release);
229 * batadv_nc_path_release() - release nc_path from lists and queue for free
230 * after rcu grace period
231 * @ref: kref pointer of the nc_path
233 static void batadv_nc_path_release(struct kref *ref)
235 struct batadv_nc_path *nc_path;
237 nc_path = container_of(ref, struct batadv_nc_path, refcount);
239 kfree_rcu(nc_path, rcu);
243 * batadv_nc_path_put() - decrement the nc_path refcounter and possibly
245 * @nc_path: nc_path to be free'd
247 static void batadv_nc_path_put(struct batadv_nc_path *nc_path)
252 kref_put(&nc_path->refcount, batadv_nc_path_release);
256 * batadv_nc_packet_free() - frees nc packet
257 * @nc_packet: the nc packet to free
258 * @dropped: whether the packet is freed because is dropped
260 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet,
264 kfree_skb(nc_packet->skb);
266 consume_skb(nc_packet->skb);
268 batadv_nc_path_put(nc_packet->nc_path);
273 * batadv_nc_to_purge_nc_node() - checks whether an nc node has to be purged
274 * @bat_priv: the bat priv with all the soft interface information
275 * @nc_node: the nc node to check
277 * Return: true if the entry has to be purged now, false otherwise
279 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
280 struct batadv_nc_node *nc_node)
282 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
285 return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
289 * batadv_nc_to_purge_nc_path_coding() - checks whether an nc path has timed out
290 * @bat_priv: the bat priv with all the soft interface information
291 * @nc_path: the nc path to check
293 * Return: true if the entry has to be purged now, false otherwise
295 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
296 struct batadv_nc_path *nc_path)
298 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
301 /* purge the path when no packets has been added for 10 times the
304 return batadv_has_timed_out(nc_path->last_valid,
305 bat_priv->nc.max_fwd_delay * 10);
309 * batadv_nc_to_purge_nc_path_decoding() - checks whether an nc path has timed
311 * @bat_priv: the bat priv with all the soft interface information
312 * @nc_path: the nc path to check
314 * Return: true if the entry has to be purged now, false otherwise
316 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
317 struct batadv_nc_path *nc_path)
319 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
322 /* purge the path when no packets has been added for 10 times the
325 return batadv_has_timed_out(nc_path->last_valid,
326 bat_priv->nc.max_buffer_time * 10);
330 * batadv_nc_purge_orig_nc_nodes() - go through list of nc nodes and purge stale
332 * @bat_priv: the bat priv with all the soft interface information
333 * @list: list of nc nodes
334 * @lock: nc node list lock
335 * @to_purge: function in charge to decide whether an entry has to be purged or
336 * not. This function takes the nc node as argument and has to return
337 * a boolean value: true if the entry has to be deleted, false
341 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
342 struct list_head *list,
344 bool (*to_purge)(struct batadv_priv *,
345 struct batadv_nc_node *))
347 struct batadv_nc_node *nc_node, *nc_node_tmp;
349 /* For each nc_node in list */
351 list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
352 /* if an helper function has been passed as parameter,
353 * ask it if the entry has to be purged or not
355 if (to_purge && !to_purge(bat_priv, nc_node))
358 batadv_dbg(BATADV_DBG_NC, bat_priv,
359 "Removing nc_node %pM -> %pM\n",
360 nc_node->addr, nc_node->orig_node->orig);
361 list_del_rcu(&nc_node->list);
362 batadv_nc_node_put(nc_node);
364 spin_unlock_bh(lock);
368 * batadv_nc_purge_orig() - purges all nc node data attached of the given
370 * @bat_priv: the bat priv with all the soft interface information
371 * @orig_node: orig_node with the nc node entries to be purged
372 * @to_purge: function in charge to decide whether an entry has to be purged or
373 * not. This function takes the nc node as argument and has to return
374 * a boolean value: true is the entry has to be deleted, false
377 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
378 struct batadv_orig_node *orig_node,
379 bool (*to_purge)(struct batadv_priv *,
380 struct batadv_nc_node *))
382 /* Check ingoing nc_node's of this orig_node */
383 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
384 &orig_node->in_coding_list_lock,
387 /* Check outgoing nc_node's of this orig_node */
388 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
389 &orig_node->out_coding_list_lock,
394 * batadv_nc_purge_orig_hash() - traverse entire originator hash to check if
395 * they have timed out nc nodes
396 * @bat_priv: the bat priv with all the soft interface information
398 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
400 struct batadv_hashtable *hash = bat_priv->orig_hash;
401 struct hlist_head *head;
402 struct batadv_orig_node *orig_node;
408 /* For each orig_node */
409 for (i = 0; i < hash->size; i++) {
410 head = &hash->table[i];
413 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
414 batadv_nc_purge_orig(bat_priv, orig_node,
415 batadv_nc_to_purge_nc_node);
421 * batadv_nc_purge_paths() - traverse all nc paths part of the hash and remove
423 * @bat_priv: the bat priv with all the soft interface information
424 * @hash: hash table containing the nc paths to check
425 * @to_purge: function in charge to decide whether an entry has to be purged or
426 * not. This function takes the nc node as argument and has to return
427 * a boolean value: true is the entry has to be deleted, false
430 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
431 struct batadv_hashtable *hash,
432 bool (*to_purge)(struct batadv_priv *,
433 struct batadv_nc_path *))
435 struct hlist_head *head;
436 struct hlist_node *node_tmp;
437 struct batadv_nc_path *nc_path;
438 spinlock_t *lock; /* Protects lists in hash */
441 for (i = 0; i < hash->size; i++) {
442 head = &hash->table[i];
443 lock = &hash->list_locks[i];
445 /* For each nc_path in this bin */
447 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
448 /* if an helper function has been passed as parameter,
449 * ask it if the entry has to be purged or not
451 if (to_purge && !to_purge(bat_priv, nc_path))
454 /* purging an non-empty nc_path should never happen, but
455 * is observed under high CPU load. Delay the purging
456 * until next iteration to allow the packet_list to be
459 if (!unlikely(list_empty(&nc_path->packet_list))) {
460 net_ratelimited_function(printk,
462 "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
468 /* nc_path is unused, so remove it */
469 batadv_dbg(BATADV_DBG_NC, bat_priv,
470 "Remove nc_path %pM -> %pM\n",
471 nc_path->prev_hop, nc_path->next_hop);
472 hlist_del_rcu(&nc_path->hash_entry);
473 batadv_nc_path_put(nc_path);
475 spin_unlock_bh(lock);
480 * batadv_nc_hash_key_gen() - computes the nc_path hash key
481 * @key: buffer to hold the final hash key
482 * @src: source ethernet mac address going into the hash key
483 * @dst: destination ethernet mac address going into the hash key
485 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
488 memcpy(key->prev_hop, src, sizeof(key->prev_hop));
489 memcpy(key->next_hop, dst, sizeof(key->next_hop));
493 * batadv_nc_hash_choose() - compute the hash value for an nc path
494 * @data: data to hash
495 * @size: size of the hash table
497 * Return: the selected index in the hash table for the given data.
499 static u32 batadv_nc_hash_choose(const void *data, u32 size)
501 const struct batadv_nc_path *nc_path = data;
504 hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
505 hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
511 * batadv_nc_hash_compare() - comparing function used in the network coding hash
513 * @node: node in the local table
514 * @data2: second object to compare the node to
516 * Return: true if the two entry are the same, false otherwise
518 static bool batadv_nc_hash_compare(const struct hlist_node *node,
521 const struct batadv_nc_path *nc_path1, *nc_path2;
523 nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
526 /* Return 1 if the two keys are identical */
527 if (!batadv_compare_eth(nc_path1->prev_hop, nc_path2->prev_hop))
530 if (!batadv_compare_eth(nc_path1->next_hop, nc_path2->next_hop))
537 * batadv_nc_hash_find() - search for an existing nc path and return it
538 * @hash: hash table containing the nc path
541 * Return: the nc_path if found, NULL otherwise.
543 static struct batadv_nc_path *
544 batadv_nc_hash_find(struct batadv_hashtable *hash,
547 struct hlist_head *head;
548 struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
554 index = batadv_nc_hash_choose(data, hash->size);
555 head = &hash->table[index];
558 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
559 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
562 if (!kref_get_unless_zero(&nc_path->refcount))
565 nc_path_tmp = nc_path;
574 * batadv_nc_send_packet() - send non-coded packet and free nc_packet struct
575 * @nc_packet: the nc packet to send
577 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
579 batadv_send_unicast_skb(nc_packet->skb, nc_packet->neigh_node);
580 nc_packet->skb = NULL;
581 batadv_nc_packet_free(nc_packet, false);
585 * batadv_nc_sniffed_purge() - Checks timestamp of given sniffed nc_packet.
586 * @bat_priv: the bat priv with all the soft interface information
587 * @nc_path: the nc path the packet belongs to
588 * @nc_packet: the nc packet to be checked
590 * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
591 * timeout. If so, the packet is no longer kept and the entry deleted from the
592 * queue. Has to be called with the appropriate locks.
594 * Return: false as soon as the entry in the fifo queue has not been timed out
595 * yet and true otherwise.
597 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
598 struct batadv_nc_path *nc_path,
599 struct batadv_nc_packet *nc_packet)
601 unsigned long timeout = bat_priv->nc.max_buffer_time;
604 lockdep_assert_held(&nc_path->packet_list_lock);
606 /* Packets are added to tail, so the remaining packets did not time
607 * out and we can stop processing the current queue
609 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
610 !batadv_has_timed_out(nc_packet->timestamp, timeout))
613 /* purge nc packet */
614 list_del(&nc_packet->list);
615 batadv_nc_packet_free(nc_packet, true);
624 * batadv_nc_fwd_flush() - Checks the timestamp of the given nc packet.
625 * @bat_priv: the bat priv with all the soft interface information
626 * @nc_path: the nc path the packet belongs to
627 * @nc_packet: the nc packet to be checked
629 * Checks whether the given nc packet has hit its forward timeout. If so, the
630 * packet is no longer delayed, immediately sent and the entry deleted from the
631 * queue. Has to be called with the appropriate locks.
633 * Return: false as soon as the entry in the fifo queue has not been timed out
634 * yet and true otherwise.
636 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
637 struct batadv_nc_path *nc_path,
638 struct batadv_nc_packet *nc_packet)
640 unsigned long timeout = bat_priv->nc.max_fwd_delay;
642 lockdep_assert_held(&nc_path->packet_list_lock);
644 /* Packets are added to tail, so the remaining packets did not time
645 * out and we can stop processing the current queue
647 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
648 !batadv_has_timed_out(nc_packet->timestamp, timeout))
652 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
653 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
654 nc_packet->skb->len + ETH_HLEN);
655 list_del(&nc_packet->list);
656 batadv_nc_send_packet(nc_packet);
662 * batadv_nc_process_nc_paths() - traverse given nc packet pool and free timed
664 * @bat_priv: the bat priv with all the soft interface information
665 * @hash: to be processed hash table
666 * @process_fn: Function called to process given nc packet. Should return true
667 * to encourage this function to proceed with the next packet.
668 * Otherwise the rest of the current queue is skipped.
671 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
672 struct batadv_hashtable *hash,
673 bool (*process_fn)(struct batadv_priv *,
674 struct batadv_nc_path *,
675 struct batadv_nc_packet *))
677 struct hlist_head *head;
678 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
679 struct batadv_nc_path *nc_path;
686 /* Loop hash table bins */
687 for (i = 0; i < hash->size; i++) {
688 head = &hash->table[i];
690 /* Loop coding paths */
692 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
694 spin_lock_bh(&nc_path->packet_list_lock);
695 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
696 &nc_path->packet_list, list) {
697 ret = process_fn(bat_priv, nc_path, nc_packet);
701 spin_unlock_bh(&nc_path->packet_list_lock);
708 * batadv_nc_worker() - periodic task for housekeeping related to network
710 * @work: kernel work struct
712 static void batadv_nc_worker(struct work_struct *work)
714 struct delayed_work *delayed_work;
715 struct batadv_priv_nc *priv_nc;
716 struct batadv_priv *bat_priv;
717 unsigned long timeout;
719 delayed_work = to_delayed_work(work);
720 priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
721 bat_priv = container_of(priv_nc, struct batadv_priv, nc);
723 batadv_nc_purge_orig_hash(bat_priv);
724 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
725 batadv_nc_to_purge_nc_path_coding);
726 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
727 batadv_nc_to_purge_nc_path_decoding);
729 timeout = bat_priv->nc.max_fwd_delay;
731 if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
732 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
733 batadv_nc_fwd_flush);
734 bat_priv->nc.timestamp_fwd_flush = jiffies;
737 if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
738 bat_priv->nc.max_buffer_time)) {
739 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
740 batadv_nc_sniffed_purge);
741 bat_priv->nc.timestamp_sniffed_purge = jiffies;
744 /* Schedule a new check */
745 batadv_nc_start_timer(bat_priv);
749 * batadv_can_nc_with_orig() - checks whether the given orig node is suitable
751 * @bat_priv: the bat priv with all the soft interface information
752 * @orig_node: neighboring orig node which may be used as nc candidate
753 * @ogm_packet: incoming ogm packet also used for the checks
756 * 1) The OGM must have the most recent sequence number.
757 * 2) The TTL must be decremented by one and only one.
758 * 3) The OGM must be received from the first hop from orig_node.
759 * 4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
761 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
762 struct batadv_orig_node *orig_node,
763 struct batadv_ogm_packet *ogm_packet)
765 struct batadv_orig_ifinfo *orig_ifinfo;
769 orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
773 last_ttl = orig_ifinfo->last_ttl;
774 last_real_seqno = orig_ifinfo->last_real_seqno;
775 batadv_orig_ifinfo_put(orig_ifinfo);
777 if (last_real_seqno != ntohl(ogm_packet->seqno))
779 if (last_ttl != ogm_packet->ttl + 1)
781 if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
783 if (ogm_packet->tq < bat_priv->nc.min_tq)
790 * batadv_nc_find_nc_node() - search for an existing nc node and return it
791 * @orig_node: orig node originating the ogm packet
792 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
793 * (can be equal to orig_node)
794 * @in_coding: traverse incoming or outgoing network coding list
796 * Return: the nc_node if found, NULL otherwise.
798 static struct batadv_nc_node *
799 batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
800 struct batadv_orig_node *orig_neigh_node,
803 struct batadv_nc_node *nc_node, *nc_node_out = NULL;
804 struct list_head *list;
807 list = &orig_neigh_node->in_coding_list;
809 list = &orig_neigh_node->out_coding_list;
811 /* Traverse list of nc_nodes to orig_node */
813 list_for_each_entry_rcu(nc_node, list, list) {
814 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
817 if (!kref_get_unless_zero(&nc_node->refcount))
821 nc_node_out = nc_node;
830 * batadv_nc_get_nc_node() - retrieves an nc node or creates the entry if it was
832 * @bat_priv: the bat priv with all the soft interface information
833 * @orig_node: orig node originating the ogm packet
834 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
835 * (can be equal to orig_node)
836 * @in_coding: traverse incoming or outgoing network coding list
838 * Return: the nc_node if found or created, NULL in case of an error.
840 static struct batadv_nc_node *
841 batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
842 struct batadv_orig_node *orig_node,
843 struct batadv_orig_node *orig_neigh_node,
846 struct batadv_nc_node *nc_node;
847 spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
848 struct list_head *list;
850 /* Select ingoing or outgoing coding node */
852 lock = &orig_neigh_node->in_coding_list_lock;
853 list = &orig_neigh_node->in_coding_list;
855 lock = &orig_neigh_node->out_coding_list_lock;
856 list = &orig_neigh_node->out_coding_list;
861 /* Check if nc_node is already added */
862 nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
868 nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
872 /* Initialize nc_node */
873 INIT_LIST_HEAD(&nc_node->list);
874 kref_init(&nc_node->refcount);
875 ether_addr_copy(nc_node->addr, orig_node->orig);
876 kref_get(&orig_neigh_node->refcount);
877 nc_node->orig_node = orig_neigh_node;
879 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
880 nc_node->addr, nc_node->orig_node->orig);
882 /* Add nc_node to orig_node */
883 kref_get(&nc_node->refcount);
884 list_add_tail_rcu(&nc_node->list, list);
887 spin_unlock_bh(lock);
893 * batadv_nc_update_nc_node() - updates stored incoming and outgoing nc node
894 * structs (best called on incoming OGMs)
895 * @bat_priv: the bat priv with all the soft interface information
896 * @orig_node: orig node originating the ogm packet
897 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
898 * (can be equal to orig_node)
899 * @ogm_packet: incoming ogm packet
900 * @is_single_hop_neigh: orig_node is a single hop neighbor
902 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
903 struct batadv_orig_node *orig_node,
904 struct batadv_orig_node *orig_neigh_node,
905 struct batadv_ogm_packet *ogm_packet,
906 int is_single_hop_neigh)
908 struct batadv_nc_node *in_nc_node = NULL;
909 struct batadv_nc_node *out_nc_node = NULL;
911 /* Check if network coding is enabled */
912 if (!atomic_read(&bat_priv->network_coding))
915 /* check if orig node is network coding enabled */
916 if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
919 /* accept ogms from 'good' neighbors and single hop neighbors */
920 if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
921 !is_single_hop_neigh)
924 /* Add orig_node as in_nc_node on hop */
925 in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
926 orig_neigh_node, true);
930 in_nc_node->last_seen = jiffies;
932 /* Add hop as out_nc_node on orig_node */
933 out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
938 out_nc_node->last_seen = jiffies;
941 batadv_nc_node_put(in_nc_node);
942 batadv_nc_node_put(out_nc_node);
946 * batadv_nc_get_path() - get existing nc_path or allocate a new one
947 * @bat_priv: the bat priv with all the soft interface information
948 * @hash: hash table containing the nc path
949 * @src: ethernet source address - first half of the nc path search key
950 * @dst: ethernet destination address - second half of the nc path search key
952 * Return: pointer to nc_path if the path was found or created, returns NULL
955 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
956 struct batadv_hashtable *hash,
961 struct batadv_nc_path *nc_path, nc_path_key;
963 batadv_nc_hash_key_gen(&nc_path_key, src, dst);
965 /* Search for existing nc_path */
966 nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
969 /* Set timestamp to delay removal of nc_path */
970 nc_path->last_valid = jiffies;
974 /* No existing nc_path was found; create a new */
975 nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
980 /* Initialize nc_path */
981 INIT_LIST_HEAD(&nc_path->packet_list);
982 spin_lock_init(&nc_path->packet_list_lock);
983 kref_init(&nc_path->refcount);
984 nc_path->last_valid = jiffies;
985 ether_addr_copy(nc_path->next_hop, dst);
986 ether_addr_copy(nc_path->prev_hop, src);
988 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
992 /* Add nc_path to hash table */
993 kref_get(&nc_path->refcount);
994 hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
995 batadv_nc_hash_choose, &nc_path_key,
996 &nc_path->hash_entry);
998 if (hash_added < 0) {
1007 * batadv_nc_random_weight_tq() - scale the receivers TQ-value to avoid unfair
1008 * selection of a receiver with slightly lower TQ than the other
1009 * @tq: to be weighted tq value
1011 * Return: scaled tq value
1013 static u8 batadv_nc_random_weight_tq(u8 tq)
1015 /* randomize the estimated packet loss (max TQ - estimated TQ) */
1016 u8 rand_tq = prandom_u32_max(BATADV_TQ_MAX_VALUE + 1 - tq);
1018 /* convert to (randomized) estimated tq again */
1019 return BATADV_TQ_MAX_VALUE - rand_tq;
1023 * batadv_nc_memxor() - XOR destination with source
1024 * @dst: byte array to XOR into
1025 * @src: byte array to XOR from
1026 * @len: length of destination array
1028 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
1032 for (i = 0; i < len; ++i)
1037 * batadv_nc_code_packets() - code a received unicast_packet with an nc packet
1038 * into a coded_packet and send it
1039 * @bat_priv: the bat priv with all the soft interface information
1040 * @skb: data skb to forward
1041 * @ethhdr: pointer to the ethernet header inside the skb
1042 * @nc_packet: structure containing the packet to the skb can be coded with
1043 * @neigh_node: next hop to forward packet to
1045 * Return: true if both packets are consumed, false otherwise.
1047 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1048 struct sk_buff *skb,
1049 struct ethhdr *ethhdr,
1050 struct batadv_nc_packet *nc_packet,
1051 struct batadv_neigh_node *neigh_node)
1053 u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1054 struct sk_buff *skb_dest, *skb_src;
1055 struct batadv_unicast_packet *packet1;
1056 struct batadv_unicast_packet *packet2;
1057 struct batadv_coded_packet *coded_packet;
1058 struct batadv_neigh_node *neigh_tmp, *router_neigh, *first_dest;
1059 struct batadv_neigh_node *router_coding = NULL, *second_dest;
1060 struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1061 struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1062 u8 *first_source, *second_source;
1063 __be32 packet_id1, packet_id2;
1067 int unicast_size = sizeof(*packet1);
1068 int coded_size = sizeof(*coded_packet);
1069 int header_add = coded_size - unicast_size;
1071 /* TODO: do we need to consider the outgoing interface for
1074 router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1079 router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1081 if (!router_neigh_ifinfo)
1084 neigh_tmp = nc_packet->neigh_node;
1085 router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1090 router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1092 if (!router_coding_ifinfo)
1095 tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1096 tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1097 tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1098 tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1100 /* Select one destination for the MAC-header dst-field based on
1101 * weighted TQ-values.
1103 if (tq_weighted_neigh >= tq_weighted_coding) {
1104 /* Destination from nc_packet is selected for MAC-header */
1105 first_dest = nc_packet->neigh_node;
1106 first_source = nc_packet->nc_path->prev_hop;
1107 second_dest = neigh_node;
1108 second_source = ethhdr->h_source;
1109 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1110 packet2 = (struct batadv_unicast_packet *)skb->data;
1111 packet_id1 = nc_packet->packet_id;
1112 packet_id2 = batadv_skb_crc32(skb,
1113 skb->data + sizeof(*packet2));
1115 /* Destination for skb is selected for MAC-header */
1116 first_dest = neigh_node;
1117 first_source = ethhdr->h_source;
1118 second_dest = nc_packet->neigh_node;
1119 second_source = nc_packet->nc_path->prev_hop;
1120 packet1 = (struct batadv_unicast_packet *)skb->data;
1121 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1122 packet_id1 = batadv_skb_crc32(skb,
1123 skb->data + sizeof(*packet1));
1124 packet_id2 = nc_packet->packet_id;
1127 /* Instead of zero padding the smallest data buffer, we
1128 * code into the largest.
1130 if (skb->len <= nc_packet->skb->len) {
1131 skb_dest = nc_packet->skb;
1135 skb_src = nc_packet->skb;
1138 /* coding_len is used when decoding the packet shorter packet */
1139 coding_len = skb_src->len - unicast_size;
1141 if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1144 skb_push(skb_dest, header_add);
1146 coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1147 skb_reset_mac_header(skb_dest);
1149 coded_packet->packet_type = BATADV_CODED;
1150 coded_packet->version = BATADV_COMPAT_VERSION;
1151 coded_packet->ttl = packet1->ttl;
1153 /* Info about first unicast packet */
1154 ether_addr_copy(coded_packet->first_source, first_source);
1155 ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1156 coded_packet->first_crc = packet_id1;
1157 coded_packet->first_ttvn = packet1->ttvn;
1159 /* Info about second unicast packet */
1160 ether_addr_copy(coded_packet->second_dest, second_dest->addr);
1161 ether_addr_copy(coded_packet->second_source, second_source);
1162 ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1163 coded_packet->second_crc = packet_id2;
1164 coded_packet->second_ttl = packet2->ttl;
1165 coded_packet->second_ttvn = packet2->ttvn;
1166 coded_packet->coded_len = htons(coding_len);
1168 /* This is where the magic happens: Code skb_src into skb_dest */
1169 batadv_nc_memxor(skb_dest->data + coded_size,
1170 skb_src->data + unicast_size, coding_len);
1172 /* Update counters accordingly */
1173 if (BATADV_SKB_CB(skb_src)->decoded &&
1174 BATADV_SKB_CB(skb_dest)->decoded) {
1175 /* Both packets are recoded */
1176 count = skb_src->len + ETH_HLEN;
1177 count += skb_dest->len + ETH_HLEN;
1178 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1179 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1180 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1181 !BATADV_SKB_CB(skb_dest)->decoded) {
1182 /* Both packets are newly coded */
1183 count = skb_src->len + ETH_HLEN;
1184 count += skb_dest->len + ETH_HLEN;
1185 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1186 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1187 } else if (BATADV_SKB_CB(skb_src)->decoded &&
1188 !BATADV_SKB_CB(skb_dest)->decoded) {
1189 /* skb_src recoded and skb_dest is newly coded */
1190 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1191 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1192 skb_src->len + ETH_HLEN);
1193 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1194 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1195 skb_dest->len + ETH_HLEN);
1196 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1197 BATADV_SKB_CB(skb_dest)->decoded) {
1198 /* skb_src is newly coded and skb_dest is recoded */
1199 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1200 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1201 skb_src->len + ETH_HLEN);
1202 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1203 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1204 skb_dest->len + ETH_HLEN);
1207 /* skb_src is now coded into skb_dest, so free it */
1208 consume_skb(skb_src);
1210 /* avoid duplicate free of skb from nc_packet */
1211 nc_packet->skb = NULL;
1212 batadv_nc_packet_free(nc_packet, false);
1214 /* Send the coded packet and return true */
1215 batadv_send_unicast_skb(skb_dest, first_dest);
1218 batadv_neigh_node_put(router_neigh);
1219 batadv_neigh_node_put(router_coding);
1220 batadv_neigh_ifinfo_put(router_neigh_ifinfo);
1221 batadv_neigh_ifinfo_put(router_coding_ifinfo);
1226 * batadv_nc_skb_coding_possible() - true if a decoded skb is available at dst.
1227 * @skb: data skb to forward
1228 * @dst: destination mac address of the other skb to code with
1229 * @src: source mac address of skb
1231 * Whenever we network code a packet we have to check whether we received it in
1232 * a network coded form. If so, we may not be able to use it for coding because
1233 * some neighbors may also have received (overheard) the packet in the network
1234 * coded form without being able to decode it. It is hard to know which of the
1235 * neighboring nodes was able to decode the packet, therefore we can only
1236 * re-code the packet if the source of the previous encoded packet is involved.
1237 * Since the source encoded the packet we can be certain it has all necessary
1238 * decode information.
1240 * Return: true if coding of a decoded packet is allowed.
1242 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1244 if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1250 * batadv_nc_path_search() - Find the coding path matching in_nc_node and
1251 * out_nc_node to retrieve a buffered packet that can be used for coding.
1252 * @bat_priv: the bat priv with all the soft interface information
1253 * @in_nc_node: pointer to skb next hop's neighbor nc node
1254 * @out_nc_node: pointer to skb source's neighbor nc node
1255 * @skb: data skb to forward
1256 * @eth_dst: next hop mac address of skb
1258 * Return: true if coding of a decoded skb is allowed.
1260 static struct batadv_nc_packet *
1261 batadv_nc_path_search(struct batadv_priv *bat_priv,
1262 struct batadv_nc_node *in_nc_node,
1263 struct batadv_nc_node *out_nc_node,
1264 struct sk_buff *skb,
1267 struct batadv_nc_path *nc_path, nc_path_key;
1268 struct batadv_nc_packet *nc_packet_out = NULL;
1269 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1270 struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1276 /* Create almost path key */
1277 batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1279 idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1281 /* Check for coding opportunities in this nc_path */
1283 hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1284 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1287 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1290 spin_lock_bh(&nc_path->packet_list_lock);
1291 if (list_empty(&nc_path->packet_list)) {
1292 spin_unlock_bh(&nc_path->packet_list_lock);
1296 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1297 &nc_path->packet_list, list) {
1298 if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1303 /* Coding opportunity is found! */
1304 list_del(&nc_packet->list);
1305 nc_packet_out = nc_packet;
1309 spin_unlock_bh(&nc_path->packet_list_lock);
1314 return nc_packet_out;
1318 * batadv_nc_skb_src_search() - Loops through the list of neighboring nodes of
1319 * the skb's sender (may be equal to the originator).
1320 * @bat_priv: the bat priv with all the soft interface information
1321 * @skb: data skb to forward
1322 * @eth_dst: next hop mac address of skb
1323 * @eth_src: source mac address of skb
1324 * @in_nc_node: pointer to skb next hop's neighbor nc node
1326 * Return: an nc packet if a suitable coding packet was found, NULL otherwise.
1328 static struct batadv_nc_packet *
1329 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1330 struct sk_buff *skb,
1333 struct batadv_nc_node *in_nc_node)
1335 struct batadv_orig_node *orig_node;
1336 struct batadv_nc_node *out_nc_node;
1337 struct batadv_nc_packet *nc_packet = NULL;
1339 orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1344 list_for_each_entry_rcu(out_nc_node,
1345 &orig_node->out_coding_list, list) {
1346 /* Check if the skb is decoded and if recoding is possible */
1347 if (!batadv_nc_skb_coding_possible(skb,
1348 out_nc_node->addr, eth_src))
1351 /* Search for an opportunity in this nc_path */
1352 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1353 out_nc_node, skb, eth_dst);
1359 batadv_orig_node_put(orig_node);
1364 * batadv_nc_skb_store_before_coding() - set the ethernet src and dst of the
1365 * unicast skb before it is stored for use in later decoding
1366 * @bat_priv: the bat priv with all the soft interface information
1367 * @skb: data skb to store
1368 * @eth_dst_new: new destination mac address of skb
1370 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1371 struct sk_buff *skb,
1374 struct ethhdr *ethhdr;
1376 /* Copy skb header to change the mac header */
1377 skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1381 /* Set the mac header as if we actually sent the packet uncoded */
1382 ethhdr = eth_hdr(skb);
1383 ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1384 ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1386 /* Set data pointer to MAC header to mimic packets from our tx path */
1387 skb_push(skb, ETH_HLEN);
1389 /* Add the packet to the decoding packet pool */
1390 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1392 /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1399 * batadv_nc_skb_dst_search() - Loops through list of neighboring nodes to dst.
1400 * @skb: data skb to forward
1401 * @neigh_node: next hop to forward packet to
1402 * @ethhdr: pointer to the ethernet header inside the skb
1404 * Loops through the list of neighboring nodes the next hop has a good
1405 * connection to (receives OGMs with a sufficient quality). We need to find a
1406 * neighbor of our next hop that potentially sent a packet which our next hop
1407 * also received (overheard) and has stored for later decoding.
1409 * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1411 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1412 struct batadv_neigh_node *neigh_node,
1413 struct ethhdr *ethhdr)
1415 struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1416 struct batadv_priv *bat_priv = netdev_priv(netdev);
1417 struct batadv_orig_node *orig_node = neigh_node->orig_node;
1418 struct batadv_nc_node *nc_node;
1419 struct batadv_nc_packet *nc_packet = NULL;
1422 list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1423 /* Search for coding opportunity with this in_nc_node */
1424 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1426 ethhdr->h_source, nc_node);
1428 /* Opportunity was found, so stop searching */
1437 /* Save packets for later decoding */
1438 batadv_nc_skb_store_before_coding(bat_priv, skb,
1440 batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1441 nc_packet->neigh_node->addr);
1443 /* Code and send packets */
1444 if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1448 /* out of mem ? Coding failed - we have to free the buffered packet
1449 * to avoid memleaks. The skb passed as argument will be dealt with
1450 * by the calling function.
1452 batadv_nc_send_packet(nc_packet);
1457 * batadv_nc_skb_add_to_path() - buffer skb for later encoding / decoding
1458 * @skb: skb to add to path
1459 * @nc_path: path to add skb to
1460 * @neigh_node: next hop to forward packet to
1461 * @packet_id: checksum to identify packet
1463 * Return: true if the packet was buffered or false in case of an error.
1465 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1466 struct batadv_nc_path *nc_path,
1467 struct batadv_neigh_node *neigh_node,
1470 struct batadv_nc_packet *nc_packet;
1472 nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1476 /* Initialize nc_packet */
1477 nc_packet->timestamp = jiffies;
1478 nc_packet->packet_id = packet_id;
1479 nc_packet->skb = skb;
1480 nc_packet->neigh_node = neigh_node;
1481 nc_packet->nc_path = nc_path;
1483 /* Add coding packet to list */
1484 spin_lock_bh(&nc_path->packet_list_lock);
1485 list_add_tail(&nc_packet->list, &nc_path->packet_list);
1486 spin_unlock_bh(&nc_path->packet_list_lock);
1492 * batadv_nc_skb_forward() - try to code a packet or add it to the coding packet
1494 * @skb: data skb to forward
1495 * @neigh_node: next hop to forward packet to
1497 * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1499 bool batadv_nc_skb_forward(struct sk_buff *skb,
1500 struct batadv_neigh_node *neigh_node)
1502 const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1503 struct batadv_priv *bat_priv = netdev_priv(netdev);
1504 struct batadv_unicast_packet *packet;
1505 struct batadv_nc_path *nc_path;
1506 struct ethhdr *ethhdr = eth_hdr(skb);
1510 /* Check if network coding is enabled */
1511 if (!atomic_read(&bat_priv->network_coding))
1514 /* We only handle unicast packets */
1515 payload = skb_network_header(skb);
1516 packet = (struct batadv_unicast_packet *)payload;
1517 if (packet->packet_type != BATADV_UNICAST)
1520 /* Try to find a coding opportunity and send the skb if one is found */
1521 if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1524 /* Find or create a nc_path for this src-dst pair */
1525 nc_path = batadv_nc_get_path(bat_priv,
1526 bat_priv->nc.coding_hash,
1533 /* Add skb to nc_path */
1534 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1535 if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1538 /* Packet is consumed */
1542 batadv_nc_path_put(nc_path);
1544 /* Packet is not consumed */
1549 * batadv_nc_skb_store_for_decoding() - save a clone of the skb which can be
1550 * used when decoding coded packets
1551 * @bat_priv: the bat priv with all the soft interface information
1552 * @skb: data skb to store
1554 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1555 struct sk_buff *skb)
1557 struct batadv_unicast_packet *packet;
1558 struct batadv_nc_path *nc_path;
1559 struct ethhdr *ethhdr = eth_hdr(skb);
1563 /* Check if network coding is enabled */
1564 if (!atomic_read(&bat_priv->network_coding))
1567 /* Check for supported packet type */
1568 payload = skb_network_header(skb);
1569 packet = (struct batadv_unicast_packet *)payload;
1570 if (packet->packet_type != BATADV_UNICAST)
1573 /* Find existing nc_path or create a new */
1574 nc_path = batadv_nc_get_path(bat_priv,
1575 bat_priv->nc.decoding_hash,
1582 /* Clone skb and adjust skb->data to point at batman header */
1583 skb = skb_clone(skb, GFP_ATOMIC);
1587 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1590 if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1593 /* Add skb to nc_path */
1594 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1595 if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1598 batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1604 batadv_nc_path_put(nc_path);
1610 * batadv_nc_skb_store_sniffed_unicast() - check if a received unicast packet
1611 * should be saved in the decoding buffer and, if so, store it there
1612 * @bat_priv: the bat priv with all the soft interface information
1613 * @skb: unicast skb to store
1615 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1616 struct sk_buff *skb)
1618 struct ethhdr *ethhdr = eth_hdr(skb);
1620 if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1623 /* Set data pointer to MAC header to mimic packets from our tx path */
1624 skb_push(skb, ETH_HLEN);
1626 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1630 * batadv_nc_skb_decode_packet() - decode given skb using the decode data stored
1632 * @bat_priv: the bat priv with all the soft interface information
1633 * @skb: unicast skb to decode
1634 * @nc_packet: decode data needed to decode the skb
1636 * Return: pointer to decoded unicast packet if the packet was decoded or NULL
1637 * in case of an error.
1639 static struct batadv_unicast_packet *
1640 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1641 struct batadv_nc_packet *nc_packet)
1643 const int h_size = sizeof(struct batadv_unicast_packet);
1644 const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1645 struct batadv_unicast_packet *unicast_packet;
1646 struct batadv_coded_packet coded_packet_tmp;
1647 struct ethhdr *ethhdr, ethhdr_tmp;
1648 u8 *orig_dest, ttl, ttvn;
1649 unsigned int coding_len;
1652 /* Save headers temporarily */
1653 memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1654 memcpy(ðhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1656 if (skb_cow(skb, 0) < 0)
1659 if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1662 /* Data points to batman header, so set mac header 14 bytes before
1663 * and network to data
1665 skb_set_mac_header(skb, -ETH_HLEN);
1666 skb_reset_network_header(skb);
1668 /* Reconstruct original mac header */
1669 ethhdr = eth_hdr(skb);
1670 *ethhdr = ethhdr_tmp;
1672 /* Select the correct unicast header information based on the location
1673 * of our mac address in the coded_packet header
1675 if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1676 /* If we are the second destination the packet was overheard,
1677 * so the Ethernet address must be copied to h_dest and
1678 * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1680 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1681 skb->pkt_type = PACKET_HOST;
1683 orig_dest = coded_packet_tmp.second_orig_dest;
1684 ttl = coded_packet_tmp.second_ttl;
1685 ttvn = coded_packet_tmp.second_ttvn;
1687 orig_dest = coded_packet_tmp.first_orig_dest;
1688 ttl = coded_packet_tmp.ttl;
1689 ttvn = coded_packet_tmp.first_ttvn;
1692 coding_len = ntohs(coded_packet_tmp.coded_len);
1694 if (coding_len > skb->len)
1697 /* Here the magic is reversed:
1698 * extract the missing packet from the received coded packet
1700 batadv_nc_memxor(skb->data + h_size,
1701 nc_packet->skb->data + h_size,
1704 /* Resize decoded skb if decoded with larger packet */
1705 if (nc_packet->skb->len > coding_len + h_size) {
1706 err = pskb_trim_rcsum(skb, coding_len + h_size);
1711 /* Create decoded unicast packet */
1712 unicast_packet = (struct batadv_unicast_packet *)skb->data;
1713 unicast_packet->packet_type = BATADV_UNICAST;
1714 unicast_packet->version = BATADV_COMPAT_VERSION;
1715 unicast_packet->ttl = ttl;
1716 ether_addr_copy(unicast_packet->dest, orig_dest);
1717 unicast_packet->ttvn = ttvn;
1719 batadv_nc_packet_free(nc_packet, false);
1720 return unicast_packet;
1724 * batadv_nc_find_decoding_packet() - search through buffered decoding data to
1725 * find the data needed to decode the coded packet
1726 * @bat_priv: the bat priv with all the soft interface information
1727 * @ethhdr: pointer to the ethernet header inside the coded packet
1728 * @coded: coded packet we try to find decode data for
1730 * Return: pointer to nc packet if the needed data was found or NULL otherwise.
1732 static struct batadv_nc_packet *
1733 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1734 struct ethhdr *ethhdr,
1735 struct batadv_coded_packet *coded)
1737 struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1738 struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1739 struct batadv_nc_path *nc_path, nc_path_key;
1747 /* Select the correct packet id based on the location of our mac-addr */
1748 dest = ethhdr->h_source;
1749 if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1750 source = coded->second_source;
1751 packet_id = coded->second_crc;
1753 source = coded->first_source;
1754 packet_id = coded->first_crc;
1757 batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1758 index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1760 /* Search for matching coding path */
1762 hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1763 /* Find matching nc_packet */
1764 spin_lock_bh(&nc_path->packet_list_lock);
1765 list_for_each_entry(tmp_nc_packet,
1766 &nc_path->packet_list, list) {
1767 if (packet_id == tmp_nc_packet->packet_id) {
1768 list_del(&tmp_nc_packet->list);
1770 nc_packet = tmp_nc_packet;
1774 spin_unlock_bh(&nc_path->packet_list_lock);
1782 batadv_dbg(BATADV_DBG_NC, bat_priv,
1783 "No decoding packet found for %u\n", packet_id);
1789 * batadv_nc_recv_coded_packet() - try to decode coded packet and enqueue the
1790 * resulting unicast packet
1791 * @skb: incoming coded packet
1792 * @recv_if: pointer to interface this packet was received on
1794 * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1797 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1798 struct batadv_hard_iface *recv_if)
1800 struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1801 struct batadv_unicast_packet *unicast_packet;
1802 struct batadv_coded_packet *coded_packet;
1803 struct batadv_nc_packet *nc_packet;
1804 struct ethhdr *ethhdr;
1805 int hdr_size = sizeof(*coded_packet);
1807 /* Check if network coding is enabled */
1808 if (!atomic_read(&bat_priv->network_coding))
1811 /* Make sure we can access (and remove) header */
1812 if (unlikely(!pskb_may_pull(skb, hdr_size)))
1815 coded_packet = (struct batadv_coded_packet *)skb->data;
1816 ethhdr = eth_hdr(skb);
1818 /* Verify frame is destined for us */
1819 if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1820 !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1823 /* Update stat counter */
1824 if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1825 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1827 nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1830 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1834 /* Make skb's linear, because decoding accesses the entire buffer */
1835 if (skb_linearize(skb) < 0)
1836 goto free_nc_packet;
1838 if (skb_linearize(nc_packet->skb) < 0)
1839 goto free_nc_packet;
1841 /* Decode the packet */
1842 unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1843 if (!unicast_packet) {
1844 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1845 goto free_nc_packet;
1848 /* Mark packet as decoded to do correct recoding when forwarding */
1849 BATADV_SKB_CB(skb)->decoded = true;
1850 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1851 batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1852 skb->len + ETH_HLEN);
1853 return batadv_recv_unicast_packet(skb, recv_if);
1856 batadv_nc_packet_free(nc_packet, true);
1864 * batadv_nc_mesh_free() - clean up network coding memory
1865 * @bat_priv: the bat priv with all the soft interface information
1867 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1869 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1870 batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1871 cancel_delayed_work_sync(&bat_priv->nc.work);
1873 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1874 batadv_hash_destroy(bat_priv->nc.coding_hash);
1875 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1876 batadv_hash_destroy(bat_priv->nc.decoding_hash);