1 /* Copyright (C) 2012-2015 B.A.T.M.A.N. contributors:
3 * Martin Hundebøll, Jeppe Ledet-Pedersen
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of version 2 of the GNU General Public
7 * License as published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
18 #include "network-coding.h"
21 #include <linux/atomic.h>
22 #include <linux/bitops.h>
23 #include <linux/byteorder/generic.h>
24 #include <linux/compiler.h>
25 #include <linux/debugfs.h>
26 #include <linux/errno.h>
27 #include <linux/etherdevice.h>
29 #include <linux/if_ether.h>
30 #include <linux/if_packet.h>
31 #include <linux/init.h>
32 #include <linux/jhash.h>
33 #include <linux/jiffies.h>
34 #include <linux/kernel.h>
35 #include <linux/list.h>
36 #include <linux/lockdep.h>
37 #include <linux/netdevice.h>
38 #include <linux/printk.h>
39 #include <linux/random.h>
40 #include <linux/rculist.h>
41 #include <linux/rcupdate.h>
42 #include <linux/seq_file.h>
43 #include <linux/skbuff.h>
44 #include <linux/slab.h>
45 #include <linux/spinlock.h>
46 #include <linux/stat.h>
47 #include <linux/stddef.h>
48 #include <linux/string.h>
49 #include <linux/workqueue.h>
51 #include "hard-interface.h"
53 #include "originator.h"
58 static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
59 static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
61 static void batadv_nc_worker(struct work_struct *work);
62 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
63 struct batadv_hard_iface *recv_if);
66 * batadv_nc_init - one-time initialization for network coding
68 int __init batadv_nc_init(void)
72 /* Register our packet type */
73 ret = batadv_recv_handler_register(BATADV_CODED,
74 batadv_nc_recv_coded_packet);
80 * batadv_nc_start_timer - initialise the nc periodic worker
81 * @bat_priv: the bat priv with all the soft interface information
83 static void batadv_nc_start_timer(struct batadv_priv *bat_priv)
85 queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work,
86 msecs_to_jiffies(10));
90 * batadv_nc_tvlv_container_update - update the network coding tvlv container
91 * after network coding setting change
92 * @bat_priv: the bat priv with all the soft interface information
94 static void batadv_nc_tvlv_container_update(struct batadv_priv *bat_priv)
98 nc_mode = atomic_read(&bat_priv->network_coding);
102 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
105 batadv_tvlv_container_register(bat_priv, BATADV_TVLV_NC, 1,
112 * batadv_nc_status_update - update the network coding tvlv container after
113 * network coding setting change
114 * @net_dev: the soft interface net device
116 void batadv_nc_status_update(struct net_device *net_dev)
118 struct batadv_priv *bat_priv = netdev_priv(net_dev);
120 batadv_nc_tvlv_container_update(bat_priv);
124 * batadv_nc_tvlv_ogm_handler_v1 - process incoming nc tvlv container
125 * @bat_priv: the bat priv with all the soft interface information
126 * @orig: the orig_node of the ogm
127 * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
128 * @tvlv_value: tvlv buffer containing the gateway data
129 * @tvlv_value_len: tvlv buffer length
131 static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
132 struct batadv_orig_node *orig,
134 void *tvlv_value, u16 tvlv_value_len)
136 if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
137 clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
139 set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
143 * batadv_nc_mesh_init - initialise coding hash table and start house keeping
144 * @bat_priv: the bat priv with all the soft interface information
146 int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
148 bat_priv->nc.timestamp_fwd_flush = jiffies;
149 bat_priv->nc.timestamp_sniffed_purge = jiffies;
151 if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
154 bat_priv->nc.coding_hash = batadv_hash_new(128);
155 if (!bat_priv->nc.coding_hash)
158 batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
159 &batadv_nc_coding_hash_lock_class_key);
161 bat_priv->nc.decoding_hash = batadv_hash_new(128);
162 if (!bat_priv->nc.decoding_hash)
165 batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
166 &batadv_nc_decoding_hash_lock_class_key);
168 INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
169 batadv_nc_start_timer(bat_priv);
171 batadv_tvlv_handler_register(bat_priv, batadv_nc_tvlv_ogm_handler_v1,
172 NULL, BATADV_TVLV_NC, 1,
173 BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
174 batadv_nc_tvlv_container_update(bat_priv);
182 * batadv_nc_init_bat_priv - initialise the nc specific bat_priv variables
183 * @bat_priv: the bat priv with all the soft interface information
185 void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
187 atomic_set(&bat_priv->network_coding, 0);
188 bat_priv->nc.min_tq = 200;
189 bat_priv->nc.max_fwd_delay = 10;
190 bat_priv->nc.max_buffer_time = 200;
194 * batadv_nc_init_orig - initialise the nc fields of an orig_node
195 * @orig_node: the orig_node which is going to be initialised
197 void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
199 INIT_LIST_HEAD(&orig_node->in_coding_list);
200 INIT_LIST_HEAD(&orig_node->out_coding_list);
201 spin_lock_init(&orig_node->in_coding_list_lock);
202 spin_lock_init(&orig_node->out_coding_list_lock);
206 * batadv_nc_node_release - release nc_node from lists and queue for free after
208 * @nc_node: the nc node to free
210 static void batadv_nc_node_release(struct batadv_nc_node *nc_node)
212 batadv_orig_node_free_ref(nc_node->orig_node);
213 kfree_rcu(nc_node, rcu);
217 * batadv_nc_node_free_ref - decrement the nc node refcounter and possibly
219 * @nc_node: the nc node to free
221 static void batadv_nc_node_free_ref(struct batadv_nc_node *nc_node)
223 if (atomic_dec_and_test(&nc_node->refcount))
224 batadv_nc_node_release(nc_node);
228 * batadv_nc_path_free_ref - decrements the nc path refcounter and possibly
230 * @nc_path: the nc node to free
232 static void batadv_nc_path_free_ref(struct batadv_nc_path *nc_path)
234 if (atomic_dec_and_test(&nc_path->refcount))
235 kfree_rcu(nc_path, rcu);
239 * batadv_nc_packet_free - frees nc packet
240 * @nc_packet: the nc packet to free
242 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet)
244 kfree_skb(nc_packet->skb);
245 batadv_nc_path_free_ref(nc_packet->nc_path);
250 * batadv_nc_to_purge_nc_node - checks whether an nc node has to be purged
251 * @bat_priv: the bat priv with all the soft interface information
252 * @nc_node: the nc node to check
254 * Returns true if the entry has to be purged now, false otherwise
256 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
257 struct batadv_nc_node *nc_node)
259 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
262 return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
266 * batadv_nc_to_purge_nc_path_coding - checks whether an nc path has timed out
267 * @bat_priv: the bat priv with all the soft interface information
268 * @nc_path: the nc path to check
270 * Returns true if the entry has to be purged now, false otherwise
272 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
273 struct batadv_nc_path *nc_path)
275 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
278 /* purge the path when no packets has been added for 10 times the
281 return batadv_has_timed_out(nc_path->last_valid,
282 bat_priv->nc.max_fwd_delay * 10);
286 * batadv_nc_to_purge_nc_path_decoding - checks whether an nc path has timed out
287 * @bat_priv: the bat priv with all the soft interface information
288 * @nc_path: the nc path to check
290 * Returns true if the entry has to be purged now, false otherwise
292 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
293 struct batadv_nc_path *nc_path)
295 if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
298 /* purge the path when no packets has been added for 10 times the
301 return batadv_has_timed_out(nc_path->last_valid,
302 bat_priv->nc.max_buffer_time * 10);
306 * batadv_nc_purge_orig_nc_nodes - go through list of nc nodes and purge stale
308 * @bat_priv: the bat priv with all the soft interface information
309 * @list: list of nc nodes
310 * @lock: nc node list lock
311 * @to_purge: function in charge to decide whether an entry has to be purged or
312 * not. This function takes the nc node as argument and has to return
313 * a boolean value: true if the entry has to be deleted, false
317 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
318 struct list_head *list,
320 bool (*to_purge)(struct batadv_priv *,
321 struct batadv_nc_node *))
323 struct batadv_nc_node *nc_node, *nc_node_tmp;
325 /* For each nc_node in list */
327 list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
328 /* if an helper function has been passed as parameter,
329 * ask it if the entry has to be purged or not
331 if (to_purge && !to_purge(bat_priv, nc_node))
334 batadv_dbg(BATADV_DBG_NC, bat_priv,
335 "Removing nc_node %pM -> %pM\n",
336 nc_node->addr, nc_node->orig_node->orig);
337 list_del_rcu(&nc_node->list);
338 batadv_nc_node_free_ref(nc_node);
340 spin_unlock_bh(lock);
344 * batadv_nc_purge_orig - purges all nc node data attached of the given
346 * @bat_priv: the bat priv with all the soft interface information
347 * @orig_node: orig_node with the nc node entries to be purged
348 * @to_purge: function in charge to decide whether an entry has to be purged or
349 * not. This function takes the nc node as argument and has to return
350 * a boolean value: true is the entry has to be deleted, false
353 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
354 struct batadv_orig_node *orig_node,
355 bool (*to_purge)(struct batadv_priv *,
356 struct batadv_nc_node *))
358 /* Check ingoing nc_node's of this orig_node */
359 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
360 &orig_node->in_coding_list_lock,
363 /* Check outgoing nc_node's of this orig_node */
364 batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
365 &orig_node->out_coding_list_lock,
370 * batadv_nc_purge_orig_hash - traverse entire originator hash to check if they
371 * have timed out nc nodes
372 * @bat_priv: the bat priv with all the soft interface information
374 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
376 struct batadv_hashtable *hash = bat_priv->orig_hash;
377 struct hlist_head *head;
378 struct batadv_orig_node *orig_node;
384 /* For each orig_node */
385 for (i = 0; i < hash->size; i++) {
386 head = &hash->table[i];
389 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
390 batadv_nc_purge_orig(bat_priv, orig_node,
391 batadv_nc_to_purge_nc_node);
397 * batadv_nc_purge_paths - traverse all nc paths part of the hash and remove
399 * @bat_priv: the bat priv with all the soft interface information
400 * @hash: hash table containing the nc paths to check
401 * @to_purge: function in charge to decide whether an entry has to be purged or
402 * not. This function takes the nc node as argument and has to return
403 * a boolean value: true is the entry has to be deleted, false
406 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
407 struct batadv_hashtable *hash,
408 bool (*to_purge)(struct batadv_priv *,
409 struct batadv_nc_path *))
411 struct hlist_head *head;
412 struct hlist_node *node_tmp;
413 struct batadv_nc_path *nc_path;
414 spinlock_t *lock; /* Protects lists in hash */
417 for (i = 0; i < hash->size; i++) {
418 head = &hash->table[i];
419 lock = &hash->list_locks[i];
421 /* For each nc_path in this bin */
423 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
424 /* if an helper function has been passed as parameter,
425 * ask it if the entry has to be purged or not
427 if (to_purge && !to_purge(bat_priv, nc_path))
430 /* purging an non-empty nc_path should never happen, but
431 * is observed under high CPU load. Delay the purging
432 * until next iteration to allow the packet_list to be
435 if (!unlikely(list_empty(&nc_path->packet_list))) {
436 net_ratelimited_function(printk,
438 "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
444 /* nc_path is unused, so remove it */
445 batadv_dbg(BATADV_DBG_NC, bat_priv,
446 "Remove nc_path %pM -> %pM\n",
447 nc_path->prev_hop, nc_path->next_hop);
448 hlist_del_rcu(&nc_path->hash_entry);
449 batadv_nc_path_free_ref(nc_path);
451 spin_unlock_bh(lock);
456 * batadv_nc_hash_key_gen - computes the nc_path hash key
457 * @key: buffer to hold the final hash key
458 * @src: source ethernet mac address going into the hash key
459 * @dst: destination ethernet mac address going into the hash key
461 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
464 memcpy(key->prev_hop, src, sizeof(key->prev_hop));
465 memcpy(key->next_hop, dst, sizeof(key->next_hop));
469 * batadv_nc_hash_choose - compute the hash value for an nc path
470 * @data: data to hash
471 * @size: size of the hash table
473 * Returns the selected index in the hash table for the given data.
475 static u32 batadv_nc_hash_choose(const void *data, u32 size)
477 const struct batadv_nc_path *nc_path = data;
480 hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
481 hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
487 * batadv_nc_hash_compare - comparing function used in the network coding hash
489 * @node: node in the local table
490 * @data2: second object to compare the node to
492 * Returns 1 if the two entry are the same, 0 otherwise
494 static int batadv_nc_hash_compare(const struct hlist_node *node,
497 const struct batadv_nc_path *nc_path1, *nc_path2;
499 nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
502 /* Return 1 if the two keys are identical */
503 if (memcmp(nc_path1->prev_hop, nc_path2->prev_hop,
504 sizeof(nc_path1->prev_hop)) != 0)
507 if (memcmp(nc_path1->next_hop, nc_path2->next_hop,
508 sizeof(nc_path1->next_hop)) != 0)
515 * batadv_nc_hash_find - search for an existing nc path and return it
516 * @hash: hash table containing the nc path
519 * Returns the nc_path if found, NULL otherwise.
521 static struct batadv_nc_path *
522 batadv_nc_hash_find(struct batadv_hashtable *hash,
525 struct hlist_head *head;
526 struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
532 index = batadv_nc_hash_choose(data, hash->size);
533 head = &hash->table[index];
536 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
537 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
540 if (!atomic_inc_not_zero(&nc_path->refcount))
543 nc_path_tmp = nc_path;
552 * batadv_nc_send_packet - send non-coded packet and free nc_packet struct
553 * @nc_packet: the nc packet to send
555 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
557 batadv_send_skb_packet(nc_packet->skb,
558 nc_packet->neigh_node->if_incoming,
559 nc_packet->nc_path->next_hop);
560 nc_packet->skb = NULL;
561 batadv_nc_packet_free(nc_packet);
565 * batadv_nc_sniffed_purge - Checks timestamp of given sniffed nc_packet.
566 * @bat_priv: the bat priv with all the soft interface information
567 * @nc_path: the nc path the packet belongs to
568 * @nc_packet: the nc packet to be checked
570 * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
571 * timeout. If so, the packet is no longer kept and the entry deleted from the
572 * queue. Has to be called with the appropriate locks.
574 * Returns false as soon as the entry in the fifo queue has not been timed out
575 * yet and true otherwise.
577 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
578 struct batadv_nc_path *nc_path,
579 struct batadv_nc_packet *nc_packet)
581 unsigned long timeout = bat_priv->nc.max_buffer_time;
584 lockdep_assert_held(&nc_path->packet_list_lock);
586 /* Packets are added to tail, so the remaining packets did not time
587 * out and we can stop processing the current queue
589 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
590 !batadv_has_timed_out(nc_packet->timestamp, timeout))
593 /* purge nc packet */
594 list_del(&nc_packet->list);
595 batadv_nc_packet_free(nc_packet);
604 * batadv_nc_fwd_flush - Checks the timestamp of the given nc packet.
605 * @bat_priv: the bat priv with all the soft interface information
606 * @nc_path: the nc path the packet belongs to
607 * @nc_packet: the nc packet to be checked
609 * Checks whether the given nc packet has hit its forward timeout. If so, the
610 * packet is no longer delayed, immediately sent and the entry deleted from the
611 * queue. Has to be called with the appropriate locks.
613 * Returns false as soon as the entry in the fifo queue has not been timed out
614 * yet and true otherwise.
616 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
617 struct batadv_nc_path *nc_path,
618 struct batadv_nc_packet *nc_packet)
620 unsigned long timeout = bat_priv->nc.max_fwd_delay;
622 lockdep_assert_held(&nc_path->packet_list_lock);
624 /* Packets are added to tail, so the remaining packets did not time
625 * out and we can stop processing the current queue
627 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
628 !batadv_has_timed_out(nc_packet->timestamp, timeout))
632 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
633 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
634 nc_packet->skb->len + ETH_HLEN);
635 list_del(&nc_packet->list);
636 batadv_nc_send_packet(nc_packet);
642 * batadv_nc_process_nc_paths - traverse given nc packet pool and free timed out
644 * @bat_priv: the bat priv with all the soft interface information
645 * @hash: to be processed hash table
646 * @process_fn: Function called to process given nc packet. Should return true
647 * to encourage this function to proceed with the next packet.
648 * Otherwise the rest of the current queue is skipped.
651 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
652 struct batadv_hashtable *hash,
653 bool (*process_fn)(struct batadv_priv *,
654 struct batadv_nc_path *,
655 struct batadv_nc_packet *))
657 struct hlist_head *head;
658 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
659 struct batadv_nc_path *nc_path;
666 /* Loop hash table bins */
667 for (i = 0; i < hash->size; i++) {
668 head = &hash->table[i];
670 /* Loop coding paths */
672 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
674 spin_lock_bh(&nc_path->packet_list_lock);
675 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
676 &nc_path->packet_list, list) {
677 ret = process_fn(bat_priv, nc_path, nc_packet);
681 spin_unlock_bh(&nc_path->packet_list_lock);
688 * batadv_nc_worker - periodic task for house keeping related to network coding
689 * @work: kernel work struct
691 static void batadv_nc_worker(struct work_struct *work)
693 struct delayed_work *delayed_work;
694 struct batadv_priv_nc *priv_nc;
695 struct batadv_priv *bat_priv;
696 unsigned long timeout;
698 delayed_work = container_of(work, struct delayed_work, work);
699 priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
700 bat_priv = container_of(priv_nc, struct batadv_priv, nc);
702 batadv_nc_purge_orig_hash(bat_priv);
703 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
704 batadv_nc_to_purge_nc_path_coding);
705 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
706 batadv_nc_to_purge_nc_path_decoding);
708 timeout = bat_priv->nc.max_fwd_delay;
710 if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
711 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
712 batadv_nc_fwd_flush);
713 bat_priv->nc.timestamp_fwd_flush = jiffies;
716 if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
717 bat_priv->nc.max_buffer_time)) {
718 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
719 batadv_nc_sniffed_purge);
720 bat_priv->nc.timestamp_sniffed_purge = jiffies;
723 /* Schedule a new check */
724 batadv_nc_start_timer(bat_priv);
728 * batadv_can_nc_with_orig - checks whether the given orig node is suitable for
730 * @bat_priv: the bat priv with all the soft interface information
731 * @orig_node: neighboring orig node which may be used as nc candidate
732 * @ogm_packet: incoming ogm packet also used for the checks
735 * 1) The OGM must have the most recent sequence number.
736 * 2) The TTL must be decremented by one and only one.
737 * 3) The OGM must be received from the first hop from orig_node.
738 * 4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
740 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
741 struct batadv_orig_node *orig_node,
742 struct batadv_ogm_packet *ogm_packet)
744 struct batadv_orig_ifinfo *orig_ifinfo;
748 orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
752 last_ttl = orig_ifinfo->last_ttl;
753 last_real_seqno = orig_ifinfo->last_real_seqno;
754 batadv_orig_ifinfo_free_ref(orig_ifinfo);
756 if (last_real_seqno != ntohl(ogm_packet->seqno))
758 if (last_ttl != ogm_packet->ttl + 1)
760 if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
762 if (ogm_packet->tq < bat_priv->nc.min_tq)
769 * batadv_nc_find_nc_node - search for an existing nc node and return it
770 * @orig_node: orig node originating the ogm packet
771 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
772 * (can be equal to orig_node)
773 * @in_coding: traverse incoming or outgoing network coding list
775 * Returns the nc_node if found, NULL otherwise.
777 static struct batadv_nc_node
778 *batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
779 struct batadv_orig_node *orig_neigh_node,
782 struct batadv_nc_node *nc_node, *nc_node_out = NULL;
783 struct list_head *list;
786 list = &orig_neigh_node->in_coding_list;
788 list = &orig_neigh_node->out_coding_list;
790 /* Traverse list of nc_nodes to orig_node */
792 list_for_each_entry_rcu(nc_node, list, list) {
793 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
796 if (!atomic_inc_not_zero(&nc_node->refcount))
800 nc_node_out = nc_node;
809 * batadv_nc_get_nc_node - retrieves an nc node or creates the entry if it was
811 * @bat_priv: the bat priv with all the soft interface information
812 * @orig_node: orig node originating the ogm packet
813 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
814 * (can be equal to orig_node)
815 * @in_coding: traverse incoming or outgoing network coding list
817 * Returns the nc_node if found or created, NULL in case of an error.
819 static struct batadv_nc_node
820 *batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
821 struct batadv_orig_node *orig_node,
822 struct batadv_orig_node *orig_neigh_node,
825 struct batadv_nc_node *nc_node;
826 spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
827 struct list_head *list;
829 /* Check if nc_node is already added */
830 nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
836 nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
840 if (!atomic_inc_not_zero(&orig_neigh_node->refcount))
843 /* Initialize nc_node */
844 INIT_LIST_HEAD(&nc_node->list);
845 ether_addr_copy(nc_node->addr, orig_node->orig);
846 nc_node->orig_node = orig_neigh_node;
847 atomic_set(&nc_node->refcount, 2);
849 /* Select ingoing or outgoing coding node */
851 lock = &orig_neigh_node->in_coding_list_lock;
852 list = &orig_neigh_node->in_coding_list;
854 lock = &orig_neigh_node->out_coding_list_lock;
855 list = &orig_neigh_node->out_coding_list;
858 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
859 nc_node->addr, nc_node->orig_node->orig);
861 /* Add nc_node to orig_node */
863 list_add_tail_rcu(&nc_node->list, list);
864 spin_unlock_bh(lock);
874 * batadv_nc_update_nc_node - updates stored incoming and outgoing nc node
875 * structs (best called on incoming OGMs)
876 * @bat_priv: the bat priv with all the soft interface information
877 * @orig_node: orig node originating the ogm packet
878 * @orig_neigh_node: neighboring orig node from which we received the ogm packet
879 * (can be equal to orig_node)
880 * @ogm_packet: incoming ogm packet
881 * @is_single_hop_neigh: orig_node is a single hop neighbor
883 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
884 struct batadv_orig_node *orig_node,
885 struct batadv_orig_node *orig_neigh_node,
886 struct batadv_ogm_packet *ogm_packet,
887 int is_single_hop_neigh)
889 struct batadv_nc_node *in_nc_node = NULL;
890 struct batadv_nc_node *out_nc_node = NULL;
892 /* Check if network coding is enabled */
893 if (!atomic_read(&bat_priv->network_coding))
896 /* check if orig node is network coding enabled */
897 if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
900 /* accept ogms from 'good' neighbors and single hop neighbors */
901 if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
902 !is_single_hop_neigh)
905 /* Add orig_node as in_nc_node on hop */
906 in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
907 orig_neigh_node, true);
911 in_nc_node->last_seen = jiffies;
913 /* Add hop as out_nc_node on orig_node */
914 out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
919 out_nc_node->last_seen = jiffies;
923 batadv_nc_node_free_ref(in_nc_node);
925 batadv_nc_node_free_ref(out_nc_node);
929 * batadv_nc_get_path - get existing nc_path or allocate a new one
930 * @bat_priv: the bat priv with all the soft interface information
931 * @hash: hash table containing the nc path
932 * @src: ethernet source address - first half of the nc path search key
933 * @dst: ethernet destination address - second half of the nc path search key
935 * Returns pointer to nc_path if the path was found or created, returns NULL
938 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
939 struct batadv_hashtable *hash,
944 struct batadv_nc_path *nc_path, nc_path_key;
946 batadv_nc_hash_key_gen(&nc_path_key, src, dst);
948 /* Search for existing nc_path */
949 nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
952 /* Set timestamp to delay removal of nc_path */
953 nc_path->last_valid = jiffies;
957 /* No existing nc_path was found; create a new */
958 nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
963 /* Initialize nc_path */
964 INIT_LIST_HEAD(&nc_path->packet_list);
965 spin_lock_init(&nc_path->packet_list_lock);
966 atomic_set(&nc_path->refcount, 2);
967 nc_path->last_valid = jiffies;
968 ether_addr_copy(nc_path->next_hop, dst);
969 ether_addr_copy(nc_path->prev_hop, src);
971 batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
975 /* Add nc_path to hash table */
976 hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
977 batadv_nc_hash_choose, &nc_path_key,
978 &nc_path->hash_entry);
980 if (hash_added < 0) {
989 * batadv_nc_random_weight_tq - scale the receivers TQ-value to avoid unfair
990 * selection of a receiver with slightly lower TQ than the other
991 * @tq: to be weighted tq value
993 static u8 batadv_nc_random_weight_tq(u8 tq)
995 u8 rand_val, rand_tq;
997 get_random_bytes(&rand_val, sizeof(rand_val));
999 /* randomize the estimated packet loss (max TQ - estimated TQ) */
1000 rand_tq = rand_val * (BATADV_TQ_MAX_VALUE - tq);
1002 /* normalize the randomized packet loss */
1003 rand_tq /= BATADV_TQ_MAX_VALUE;
1005 /* convert to (randomized) estimated tq again */
1006 return BATADV_TQ_MAX_VALUE - rand_tq;
1010 * batadv_nc_memxor - XOR destination with source
1011 * @dst: byte array to XOR into
1012 * @src: byte array to XOR from
1013 * @len: length of destination array
1015 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
1019 for (i = 0; i < len; ++i)
1024 * batadv_nc_code_packets - code a received unicast_packet with an nc packet
1025 * into a coded_packet and send it
1026 * @bat_priv: the bat priv with all the soft interface information
1027 * @skb: data skb to forward
1028 * @ethhdr: pointer to the ethernet header inside the skb
1029 * @nc_packet: structure containing the packet to the skb can be coded with
1030 * @neigh_node: next hop to forward packet to
1032 * Returns true if both packets are consumed, false otherwise.
1034 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1035 struct sk_buff *skb,
1036 struct ethhdr *ethhdr,
1037 struct batadv_nc_packet *nc_packet,
1038 struct batadv_neigh_node *neigh_node)
1040 u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1041 struct sk_buff *skb_dest, *skb_src;
1042 struct batadv_unicast_packet *packet1;
1043 struct batadv_unicast_packet *packet2;
1044 struct batadv_coded_packet *coded_packet;
1045 struct batadv_neigh_node *neigh_tmp, *router_neigh;
1046 struct batadv_neigh_node *router_coding = NULL;
1047 struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1048 struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1049 u8 *first_source, *first_dest, *second_source, *second_dest;
1050 __be32 packet_id1, packet_id2;
1054 int unicast_size = sizeof(*packet1);
1055 int coded_size = sizeof(*coded_packet);
1056 int header_add = coded_size - unicast_size;
1058 /* TODO: do we need to consider the outgoing interface for
1061 router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1066 router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1068 if (!router_neigh_ifinfo)
1071 neigh_tmp = nc_packet->neigh_node;
1072 router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1077 router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1079 if (!router_coding_ifinfo)
1082 tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1083 tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1084 tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1085 tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1087 /* Select one destination for the MAC-header dst-field based on
1088 * weighted TQ-values.
1090 if (tq_weighted_neigh >= tq_weighted_coding) {
1091 /* Destination from nc_packet is selected for MAC-header */
1092 first_dest = nc_packet->nc_path->next_hop;
1093 first_source = nc_packet->nc_path->prev_hop;
1094 second_dest = neigh_node->addr;
1095 second_source = ethhdr->h_source;
1096 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1097 packet2 = (struct batadv_unicast_packet *)skb->data;
1098 packet_id1 = nc_packet->packet_id;
1099 packet_id2 = batadv_skb_crc32(skb,
1100 skb->data + sizeof(*packet2));
1102 /* Destination for skb is selected for MAC-header */
1103 first_dest = neigh_node->addr;
1104 first_source = ethhdr->h_source;
1105 second_dest = nc_packet->nc_path->next_hop;
1106 second_source = nc_packet->nc_path->prev_hop;
1107 packet1 = (struct batadv_unicast_packet *)skb->data;
1108 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1109 packet_id1 = batadv_skb_crc32(skb,
1110 skb->data + sizeof(*packet1));
1111 packet_id2 = nc_packet->packet_id;
1114 /* Instead of zero padding the smallest data buffer, we
1115 * code into the largest.
1117 if (skb->len <= nc_packet->skb->len) {
1118 skb_dest = nc_packet->skb;
1122 skb_src = nc_packet->skb;
1125 /* coding_len is used when decoding the packet shorter packet */
1126 coding_len = skb_src->len - unicast_size;
1128 if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1131 skb_push(skb_dest, header_add);
1133 coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1134 skb_reset_mac_header(skb_dest);
1136 coded_packet->packet_type = BATADV_CODED;
1137 coded_packet->version = BATADV_COMPAT_VERSION;
1138 coded_packet->ttl = packet1->ttl;
1140 /* Info about first unicast packet */
1141 ether_addr_copy(coded_packet->first_source, first_source);
1142 ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1143 coded_packet->first_crc = packet_id1;
1144 coded_packet->first_ttvn = packet1->ttvn;
1146 /* Info about second unicast packet */
1147 ether_addr_copy(coded_packet->second_dest, second_dest);
1148 ether_addr_copy(coded_packet->second_source, second_source);
1149 ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1150 coded_packet->second_crc = packet_id2;
1151 coded_packet->second_ttl = packet2->ttl;
1152 coded_packet->second_ttvn = packet2->ttvn;
1153 coded_packet->coded_len = htons(coding_len);
1155 /* This is where the magic happens: Code skb_src into skb_dest */
1156 batadv_nc_memxor(skb_dest->data + coded_size,
1157 skb_src->data + unicast_size, coding_len);
1159 /* Update counters accordingly */
1160 if (BATADV_SKB_CB(skb_src)->decoded &&
1161 BATADV_SKB_CB(skb_dest)->decoded) {
1162 /* Both packets are recoded */
1163 count = skb_src->len + ETH_HLEN;
1164 count += skb_dest->len + ETH_HLEN;
1165 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1166 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1167 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1168 !BATADV_SKB_CB(skb_dest)->decoded) {
1169 /* Both packets are newly coded */
1170 count = skb_src->len + ETH_HLEN;
1171 count += skb_dest->len + ETH_HLEN;
1172 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1173 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1174 } else if (BATADV_SKB_CB(skb_src)->decoded &&
1175 !BATADV_SKB_CB(skb_dest)->decoded) {
1176 /* skb_src recoded and skb_dest is newly coded */
1177 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1178 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1179 skb_src->len + ETH_HLEN);
1180 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1181 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1182 skb_dest->len + ETH_HLEN);
1183 } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1184 BATADV_SKB_CB(skb_dest)->decoded) {
1185 /* skb_src is newly coded and skb_dest is recoded */
1186 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1187 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1188 skb_src->len + ETH_HLEN);
1189 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1190 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1191 skb_dest->len + ETH_HLEN);
1194 /* skb_src is now coded into skb_dest, so free it */
1197 /* avoid duplicate free of skb from nc_packet */
1198 nc_packet->skb = NULL;
1199 batadv_nc_packet_free(nc_packet);
1201 /* Send the coded packet and return true */
1202 batadv_send_skb_packet(skb_dest, neigh_node->if_incoming, first_dest);
1206 batadv_neigh_node_free_ref(router_neigh);
1208 batadv_neigh_node_free_ref(router_coding);
1209 if (router_neigh_ifinfo)
1210 batadv_neigh_ifinfo_free_ref(router_neigh_ifinfo);
1211 if (router_coding_ifinfo)
1212 batadv_neigh_ifinfo_free_ref(router_coding_ifinfo);
1217 * batadv_nc_skb_coding_possible - true if a decoded skb is available at dst.
1218 * @skb: data skb to forward
1219 * @dst: destination mac address of the other skb to code with
1220 * @src: source mac address of skb
1222 * Whenever we network code a packet we have to check whether we received it in
1223 * a network coded form. If so, we may not be able to use it for coding because
1224 * some neighbors may also have received (overheard) the packet in the network
1225 * coded form without being able to decode it. It is hard to know which of the
1226 * neighboring nodes was able to decode the packet, therefore we can only
1227 * re-code the packet if the source of the previous encoded packet is involved.
1228 * Since the source encoded the packet we can be certain it has all necessary
1229 * decode information.
1231 * Returns true if coding of a decoded packet is allowed.
1233 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1235 if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1241 * batadv_nc_path_search - Find the coding path matching in_nc_node and
1242 * out_nc_node to retrieve a buffered packet that can be used for coding.
1243 * @bat_priv: the bat priv with all the soft interface information
1244 * @in_nc_node: pointer to skb next hop's neighbor nc node
1245 * @out_nc_node: pointer to skb source's neighbor nc node
1246 * @skb: data skb to forward
1247 * @eth_dst: next hop mac address of skb
1249 * Returns true if coding of a decoded skb is allowed.
1251 static struct batadv_nc_packet *
1252 batadv_nc_path_search(struct batadv_priv *bat_priv,
1253 struct batadv_nc_node *in_nc_node,
1254 struct batadv_nc_node *out_nc_node,
1255 struct sk_buff *skb,
1258 struct batadv_nc_path *nc_path, nc_path_key;
1259 struct batadv_nc_packet *nc_packet_out = NULL;
1260 struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1261 struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1267 /* Create almost path key */
1268 batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1270 idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1272 /* Check for coding opportunities in this nc_path */
1274 hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1275 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1278 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1281 spin_lock_bh(&nc_path->packet_list_lock);
1282 if (list_empty(&nc_path->packet_list)) {
1283 spin_unlock_bh(&nc_path->packet_list_lock);
1287 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1288 &nc_path->packet_list, list) {
1289 if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1294 /* Coding opportunity is found! */
1295 list_del(&nc_packet->list);
1296 nc_packet_out = nc_packet;
1300 spin_unlock_bh(&nc_path->packet_list_lock);
1305 return nc_packet_out;
1309 * batadv_nc_skb_src_search - Loops through the list of neighoring nodes of the
1310 * skb's sender (may be equal to the originator).
1311 * @bat_priv: the bat priv with all the soft interface information
1312 * @skb: data skb to forward
1313 * @eth_dst: next hop mac address of skb
1314 * @eth_src: source mac address of skb
1315 * @in_nc_node: pointer to skb next hop's neighbor nc node
1317 * Returns an nc packet if a suitable coding packet was found, NULL otherwise.
1319 static struct batadv_nc_packet *
1320 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1321 struct sk_buff *skb,
1324 struct batadv_nc_node *in_nc_node)
1326 struct batadv_orig_node *orig_node;
1327 struct batadv_nc_node *out_nc_node;
1328 struct batadv_nc_packet *nc_packet = NULL;
1330 orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1335 list_for_each_entry_rcu(out_nc_node,
1336 &orig_node->out_coding_list, list) {
1337 /* Check if the skb is decoded and if recoding is possible */
1338 if (!batadv_nc_skb_coding_possible(skb,
1339 out_nc_node->addr, eth_src))
1342 /* Search for an opportunity in this nc_path */
1343 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1344 out_nc_node, skb, eth_dst);
1350 batadv_orig_node_free_ref(orig_node);
1355 * batadv_nc_skb_store_before_coding - set the ethernet src and dst of the
1356 * unicast skb before it is stored for use in later decoding
1357 * @bat_priv: the bat priv with all the soft interface information
1358 * @skb: data skb to store
1359 * @eth_dst_new: new destination mac address of skb
1361 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1362 struct sk_buff *skb,
1365 struct ethhdr *ethhdr;
1367 /* Copy skb header to change the mac header */
1368 skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1372 /* Set the mac header as if we actually sent the packet uncoded */
1373 ethhdr = eth_hdr(skb);
1374 ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1375 ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1377 /* Set data pointer to MAC header to mimic packets from our tx path */
1378 skb_push(skb, ETH_HLEN);
1380 /* Add the packet to the decoding packet pool */
1381 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1383 /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1390 * batadv_nc_skb_dst_search - Loops through list of neighboring nodes to dst.
1391 * @skb: data skb to forward
1392 * @neigh_node: next hop to forward packet to
1393 * @ethhdr: pointer to the ethernet header inside the skb
1395 * Loops through list of neighboring nodes the next hop has a good connection to
1396 * (receives OGMs with a sufficient quality). We need to find a neighbor of our
1397 * next hop that potentially sent a packet which our next hop also received
1398 * (overheard) and has stored for later decoding.
1400 * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1402 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1403 struct batadv_neigh_node *neigh_node,
1404 struct ethhdr *ethhdr)
1406 struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1407 struct batadv_priv *bat_priv = netdev_priv(netdev);
1408 struct batadv_orig_node *orig_node = neigh_node->orig_node;
1409 struct batadv_nc_node *nc_node;
1410 struct batadv_nc_packet *nc_packet = NULL;
1413 list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1414 /* Search for coding opportunity with this in_nc_node */
1415 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1417 ethhdr->h_source, nc_node);
1419 /* Opportunity was found, so stop searching */
1428 /* Save packets for later decoding */
1429 batadv_nc_skb_store_before_coding(bat_priv, skb,
1431 batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1432 nc_packet->neigh_node->addr);
1434 /* Code and send packets */
1435 if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1439 /* out of mem ? Coding failed - we have to free the buffered packet
1440 * to avoid memleaks. The skb passed as argument will be dealt with
1441 * by the calling function.
1443 batadv_nc_send_packet(nc_packet);
1448 * batadv_nc_skb_add_to_path - buffer skb for later encoding / decoding
1449 * @skb: skb to add to path
1450 * @nc_path: path to add skb to
1451 * @neigh_node: next hop to forward packet to
1452 * @packet_id: checksum to identify packet
1454 * Returns true if the packet was buffered or false in case of an error.
1456 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1457 struct batadv_nc_path *nc_path,
1458 struct batadv_neigh_node *neigh_node,
1461 struct batadv_nc_packet *nc_packet;
1463 nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1467 /* Initialize nc_packet */
1468 nc_packet->timestamp = jiffies;
1469 nc_packet->packet_id = packet_id;
1470 nc_packet->skb = skb;
1471 nc_packet->neigh_node = neigh_node;
1472 nc_packet->nc_path = nc_path;
1474 /* Add coding packet to list */
1475 spin_lock_bh(&nc_path->packet_list_lock);
1476 list_add_tail(&nc_packet->list, &nc_path->packet_list);
1477 spin_unlock_bh(&nc_path->packet_list_lock);
1483 * batadv_nc_skb_forward - try to code a packet or add it to the coding packet
1485 * @skb: data skb to forward
1486 * @neigh_node: next hop to forward packet to
1488 * Returns true if the skb was consumed (encoded packet sent) or false otherwise
1490 bool batadv_nc_skb_forward(struct sk_buff *skb,
1491 struct batadv_neigh_node *neigh_node)
1493 const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1494 struct batadv_priv *bat_priv = netdev_priv(netdev);
1495 struct batadv_unicast_packet *packet;
1496 struct batadv_nc_path *nc_path;
1497 struct ethhdr *ethhdr = eth_hdr(skb);
1501 /* Check if network coding is enabled */
1502 if (!atomic_read(&bat_priv->network_coding))
1505 /* We only handle unicast packets */
1506 payload = skb_network_header(skb);
1507 packet = (struct batadv_unicast_packet *)payload;
1508 if (packet->packet_type != BATADV_UNICAST)
1511 /* Try to find a coding opportunity and send the skb if one is found */
1512 if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1515 /* Find or create a nc_path for this src-dst pair */
1516 nc_path = batadv_nc_get_path(bat_priv,
1517 bat_priv->nc.coding_hash,
1524 /* Add skb to nc_path */
1525 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1526 if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1529 /* Packet is consumed */
1533 batadv_nc_path_free_ref(nc_path);
1535 /* Packet is not consumed */
1540 * batadv_nc_skb_store_for_decoding - save a clone of the skb which can be used
1541 * when decoding coded packets
1542 * @bat_priv: the bat priv with all the soft interface information
1543 * @skb: data skb to store
1545 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1546 struct sk_buff *skb)
1548 struct batadv_unicast_packet *packet;
1549 struct batadv_nc_path *nc_path;
1550 struct ethhdr *ethhdr = eth_hdr(skb);
1554 /* Check if network coding is enabled */
1555 if (!atomic_read(&bat_priv->network_coding))
1558 /* Check for supported packet type */
1559 payload = skb_network_header(skb);
1560 packet = (struct batadv_unicast_packet *)payload;
1561 if (packet->packet_type != BATADV_UNICAST)
1564 /* Find existing nc_path or create a new */
1565 nc_path = batadv_nc_get_path(bat_priv,
1566 bat_priv->nc.decoding_hash,
1573 /* Clone skb and adjust skb->data to point at batman header */
1574 skb = skb_clone(skb, GFP_ATOMIC);
1578 if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1581 if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1584 /* Add skb to nc_path */
1585 packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1586 if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1589 batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1595 batadv_nc_path_free_ref(nc_path);
1601 * batadv_nc_skb_store_sniffed_unicast - check if a received unicast packet
1602 * should be saved in the decoding buffer and, if so, store it there
1603 * @bat_priv: the bat priv with all the soft interface information
1604 * @skb: unicast skb to store
1606 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1607 struct sk_buff *skb)
1609 struct ethhdr *ethhdr = eth_hdr(skb);
1611 if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1614 /* Set data pointer to MAC header to mimic packets from our tx path */
1615 skb_push(skb, ETH_HLEN);
1617 batadv_nc_skb_store_for_decoding(bat_priv, skb);
1621 * batadv_nc_skb_decode_packet - decode given skb using the decode data stored
1623 * @bat_priv: the bat priv with all the soft interface information
1624 * @skb: unicast skb to decode
1625 * @nc_packet: decode data needed to decode the skb
1627 * Returns pointer to decoded unicast packet if the packet was decoded or NULL
1628 * in case of an error.
1630 static struct batadv_unicast_packet *
1631 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1632 struct batadv_nc_packet *nc_packet)
1634 const int h_size = sizeof(struct batadv_unicast_packet);
1635 const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1636 struct batadv_unicast_packet *unicast_packet;
1637 struct batadv_coded_packet coded_packet_tmp;
1638 struct ethhdr *ethhdr, ethhdr_tmp;
1639 u8 *orig_dest, ttl, ttvn;
1640 unsigned int coding_len;
1643 /* Save headers temporarily */
1644 memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1645 memcpy(ðhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1647 if (skb_cow(skb, 0) < 0)
1650 if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1653 /* Data points to batman header, so set mac header 14 bytes before
1654 * and network to data
1656 skb_set_mac_header(skb, -ETH_HLEN);
1657 skb_reset_network_header(skb);
1659 /* Reconstruct original mac header */
1660 ethhdr = eth_hdr(skb);
1661 *ethhdr = ethhdr_tmp;
1663 /* Select the correct unicast header information based on the location
1664 * of our mac address in the coded_packet header
1666 if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1667 /* If we are the second destination the packet was overheard,
1668 * so the Ethernet address must be copied to h_dest and
1669 * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1671 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1672 skb->pkt_type = PACKET_HOST;
1674 orig_dest = coded_packet_tmp.second_orig_dest;
1675 ttl = coded_packet_tmp.second_ttl;
1676 ttvn = coded_packet_tmp.second_ttvn;
1678 orig_dest = coded_packet_tmp.first_orig_dest;
1679 ttl = coded_packet_tmp.ttl;
1680 ttvn = coded_packet_tmp.first_ttvn;
1683 coding_len = ntohs(coded_packet_tmp.coded_len);
1685 if (coding_len > skb->len)
1688 /* Here the magic is reversed:
1689 * extract the missing packet from the received coded packet
1691 batadv_nc_memxor(skb->data + h_size,
1692 nc_packet->skb->data + h_size,
1695 /* Resize decoded skb if decoded with larger packet */
1696 if (nc_packet->skb->len > coding_len + h_size) {
1697 err = pskb_trim_rcsum(skb, coding_len + h_size);
1702 /* Create decoded unicast packet */
1703 unicast_packet = (struct batadv_unicast_packet *)skb->data;
1704 unicast_packet->packet_type = BATADV_UNICAST;
1705 unicast_packet->version = BATADV_COMPAT_VERSION;
1706 unicast_packet->ttl = ttl;
1707 ether_addr_copy(unicast_packet->dest, orig_dest);
1708 unicast_packet->ttvn = ttvn;
1710 batadv_nc_packet_free(nc_packet);
1711 return unicast_packet;
1715 * batadv_nc_find_decoding_packet - search through buffered decoding data to
1716 * find the data needed to decode the coded packet
1717 * @bat_priv: the bat priv with all the soft interface information
1718 * @ethhdr: pointer to the ethernet header inside the coded packet
1719 * @coded: coded packet we try to find decode data for
1721 * Returns pointer to nc packet if the needed data was found or NULL otherwise.
1723 static struct batadv_nc_packet *
1724 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1725 struct ethhdr *ethhdr,
1726 struct batadv_coded_packet *coded)
1728 struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1729 struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1730 struct batadv_nc_path *nc_path, nc_path_key;
1738 /* Select the correct packet id based on the location of our mac-addr */
1739 dest = ethhdr->h_source;
1740 if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1741 source = coded->second_source;
1742 packet_id = coded->second_crc;
1744 source = coded->first_source;
1745 packet_id = coded->first_crc;
1748 batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1749 index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1751 /* Search for matching coding path */
1753 hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1754 /* Find matching nc_packet */
1755 spin_lock_bh(&nc_path->packet_list_lock);
1756 list_for_each_entry(tmp_nc_packet,
1757 &nc_path->packet_list, list) {
1758 if (packet_id == tmp_nc_packet->packet_id) {
1759 list_del(&tmp_nc_packet->list);
1761 nc_packet = tmp_nc_packet;
1765 spin_unlock_bh(&nc_path->packet_list_lock);
1773 batadv_dbg(BATADV_DBG_NC, bat_priv,
1774 "No decoding packet found for %u\n", packet_id);
1780 * batadv_nc_recv_coded_packet - try to decode coded packet and enqueue the
1781 * resulting unicast packet
1782 * @skb: incoming coded packet
1783 * @recv_if: pointer to interface this packet was received on
1785 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1786 struct batadv_hard_iface *recv_if)
1788 struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1789 struct batadv_unicast_packet *unicast_packet;
1790 struct batadv_coded_packet *coded_packet;
1791 struct batadv_nc_packet *nc_packet;
1792 struct ethhdr *ethhdr;
1793 int hdr_size = sizeof(*coded_packet);
1795 /* Check if network coding is enabled */
1796 if (!atomic_read(&bat_priv->network_coding))
1799 /* Make sure we can access (and remove) header */
1800 if (unlikely(!pskb_may_pull(skb, hdr_size)))
1803 coded_packet = (struct batadv_coded_packet *)skb->data;
1804 ethhdr = eth_hdr(skb);
1806 /* Verify frame is destined for us */
1807 if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1808 !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1811 /* Update stat counter */
1812 if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1813 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1815 nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1818 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1822 /* Make skb's linear, because decoding accesses the entire buffer */
1823 if (skb_linearize(skb) < 0)
1824 goto free_nc_packet;
1826 if (skb_linearize(nc_packet->skb) < 0)
1827 goto free_nc_packet;
1829 /* Decode the packet */
1830 unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1831 if (!unicast_packet) {
1832 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1833 goto free_nc_packet;
1836 /* Mark packet as decoded to do correct recoding when forwarding */
1837 BATADV_SKB_CB(skb)->decoded = true;
1838 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1839 batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1840 skb->len + ETH_HLEN);
1841 return batadv_recv_unicast_packet(skb, recv_if);
1844 batadv_nc_packet_free(nc_packet);
1849 * batadv_nc_mesh_free - clean up network coding memory
1850 * @bat_priv: the bat priv with all the soft interface information
1852 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1854 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1855 batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1856 cancel_delayed_work_sync(&bat_priv->nc.work);
1858 batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1859 batadv_hash_destroy(bat_priv->nc.coding_hash);
1860 batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1861 batadv_hash_destroy(bat_priv->nc.decoding_hash);
1865 * batadv_nc_nodes_seq_print_text - print the nc node information
1866 * @seq: seq file to print on
1869 int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
1871 struct net_device *net_dev = (struct net_device *)seq->private;
1872 struct batadv_priv *bat_priv = netdev_priv(net_dev);
1873 struct batadv_hashtable *hash = bat_priv->orig_hash;
1874 struct batadv_hard_iface *primary_if;
1875 struct hlist_head *head;
1876 struct batadv_orig_node *orig_node;
1877 struct batadv_nc_node *nc_node;
1880 primary_if = batadv_seq_print_text_primary_if_get(seq);
1884 /* Traverse list of originators */
1885 for (i = 0; i < hash->size; i++) {
1886 head = &hash->table[i];
1888 /* For each orig_node in this bin */
1890 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1891 /* no need to print the orig node if it does not have
1892 * network coding neighbors
1894 if (list_empty(&orig_node->in_coding_list) &&
1895 list_empty(&orig_node->out_coding_list))
1898 seq_printf(seq, "Node: %pM\n", orig_node->orig);
1900 seq_puts(seq, " Ingoing: ");
1901 /* For each in_nc_node to this orig_node */
1902 list_for_each_entry_rcu(nc_node,
1903 &orig_node->in_coding_list,
1905 seq_printf(seq, "%pM ",
1907 seq_puts(seq, "\n");
1909 seq_puts(seq, " Outgoing: ");
1910 /* For out_nc_node to this orig_node */
1911 list_for_each_entry_rcu(nc_node,
1912 &orig_node->out_coding_list,
1914 seq_printf(seq, "%pM ",
1916 seq_puts(seq, "\n\n");
1923 batadv_hardif_free_ref(primary_if);
1928 * batadv_nc_init_debugfs - create nc folder and related files in debugfs
1929 * @bat_priv: the bat priv with all the soft interface information
1931 int batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
1933 struct dentry *nc_dir, *file;
1935 nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
1939 file = debugfs_create_u8("min_tq", S_IRUGO | S_IWUSR, nc_dir,
1940 &bat_priv->nc.min_tq);
1944 file = debugfs_create_u32("max_fwd_delay", S_IRUGO | S_IWUSR, nc_dir,
1945 &bat_priv->nc.max_fwd_delay);
1949 file = debugfs_create_u32("max_buffer_time", S_IRUGO | S_IWUSR, nc_dir,
1950 &bat_priv->nc.max_buffer_time);