~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/batman-adv/network-coding.c

Version: ~ [ linux-5.15-rc6 ] ~ [ linux-5.14.14 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.75 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.155 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.213 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.252 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.287 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.289 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0
  2 /* Copyright (C) 2012-2018  B.A.T.M.A.N. contributors:
  3  *
  4  * Martin Hundebøll, Jeppe Ledet-Pedersen
  5  *
  6  * This program is free software; you can redistribute it and/or
  7  * modify it under the terms of version 2 of the GNU General Public
  8  * License as published by the Free Software Foundation.
  9  *
 10  * This program is distributed in the hope that it will be useful, but
 11  * WITHOUT ANY WARRANTY; without even the implied warranty of
 12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 13  * General Public License for more details.
 14  *
 15  * You should have received a copy of the GNU General Public License
 16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
 17  */
 18 
 19 #include "network-coding.h"
 20 #include "main.h"
 21 
 22 #include <linux/atomic.h>
 23 #include <linux/bitops.h>
 24 #include <linux/byteorder/generic.h>
 25 #include <linux/compiler.h>
 26 #include <linux/debugfs.h>
 27 #include <linux/errno.h>
 28 #include <linux/etherdevice.h>
 29 #include <linux/gfp.h>
 30 #include <linux/if_ether.h>
 31 #include <linux/if_packet.h>
 32 #include <linux/init.h>
 33 #include <linux/jhash.h>
 34 #include <linux/jiffies.h>
 35 #include <linux/kernel.h>
 36 #include <linux/kref.h>
 37 #include <linux/list.h>
 38 #include <linux/lockdep.h>
 39 #include <linux/net.h>
 40 #include <linux/netdevice.h>
 41 #include <linux/printk.h>
 42 #include <linux/random.h>
 43 #include <linux/rculist.h>
 44 #include <linux/rcupdate.h>
 45 #include <linux/seq_file.h>
 46 #include <linux/skbuff.h>
 47 #include <linux/slab.h>
 48 #include <linux/spinlock.h>
 49 #include <linux/stddef.h>
 50 #include <linux/string.h>
 51 #include <linux/workqueue.h>
 52 #include <uapi/linux/batadv_packet.h>
 53 
 54 #include "hard-interface.h"
 55 #include "hash.h"
 56 #include "log.h"
 57 #include "originator.h"
 58 #include "routing.h"
 59 #include "send.h"
 60 #include "tvlv.h"
 61 
 62 static struct lock_class_key batadv_nc_coding_hash_lock_class_key;
 63 static struct lock_class_key batadv_nc_decoding_hash_lock_class_key;
 64 
 65 static void batadv_nc_worker(struct work_struct *work);
 66 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
 67                                        struct batadv_hard_iface *recv_if);
 68 
 69 /**
 70  * batadv_nc_init() - one-time initialization for network coding
 71  *
 72  * Return: 0 on success or negative error number in case of failure
 73  */
 74 int __init batadv_nc_init(void)
 75 {
 76         int ret;
 77 
 78         /* Register our packet type */
 79         ret = batadv_recv_handler_register(BATADV_CODED,
 80                                            batadv_nc_recv_coded_packet);
 81 
 82         return ret;
 83 }
 84 
 85 /**
 86  * batadv_nc_start_timer() - initialise the nc periodic worker
 87  * @bat_priv: the bat priv with all the soft interface information
 88  */
 89 static void batadv_nc_start_timer(struct batadv_priv *bat_priv)
 90 {
 91         queue_delayed_work(batadv_event_workqueue, &bat_priv->nc.work,
 92                            msecs_to_jiffies(10));
 93 }
 94 
 95 /**
 96  * batadv_nc_tvlv_container_update() - update the network coding tvlv container
 97  *  after network coding setting change
 98  * @bat_priv: the bat priv with all the soft interface information
 99  */
100 static void batadv_nc_tvlv_container_update(struct batadv_priv *bat_priv)
101 {
102         char nc_mode;
103 
104         nc_mode = atomic_read(&bat_priv->network_coding);
105 
106         switch (nc_mode) {
107         case 0:
108                 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
109                 break;
110         case 1:
111                 batadv_tvlv_container_register(bat_priv, BATADV_TVLV_NC, 1,
112                                                NULL, 0);
113                 break;
114         }
115 }
116 
117 /**
118  * batadv_nc_status_update() - update the network coding tvlv container after
119  *  network coding setting change
120  * @net_dev: the soft interface net device
121  */
122 void batadv_nc_status_update(struct net_device *net_dev)
123 {
124         struct batadv_priv *bat_priv = netdev_priv(net_dev);
125 
126         batadv_nc_tvlv_container_update(bat_priv);
127 }
128 
129 /**
130  * batadv_nc_tvlv_ogm_handler_v1() - process incoming nc tvlv container
131  * @bat_priv: the bat priv with all the soft interface information
132  * @orig: the orig_node of the ogm
133  * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
134  * @tvlv_value: tvlv buffer containing the gateway data
135  * @tvlv_value_len: tvlv buffer length
136  */
137 static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
138                                           struct batadv_orig_node *orig,
139                                           u8 flags,
140                                           void *tvlv_value, u16 tvlv_value_len)
141 {
142         if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
143                 clear_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
144         else
145                 set_bit(BATADV_ORIG_CAPA_HAS_NC, &orig->capabilities);
146 }
147 
148 /**
149  * batadv_nc_mesh_init() - initialise coding hash table and start house keeping
150  * @bat_priv: the bat priv with all the soft interface information
151  *
152  * Return: 0 on success or negative error number in case of failure
153  */
154 int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
155 {
156         bat_priv->nc.timestamp_fwd_flush = jiffies;
157         bat_priv->nc.timestamp_sniffed_purge = jiffies;
158 
159         if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash)
160                 return 0;
161 
162         bat_priv->nc.coding_hash = batadv_hash_new(128);
163         if (!bat_priv->nc.coding_hash)
164                 goto err;
165 
166         batadv_hash_set_lock_class(bat_priv->nc.coding_hash,
167                                    &batadv_nc_coding_hash_lock_class_key);
168 
169         bat_priv->nc.decoding_hash = batadv_hash_new(128);
170         if (!bat_priv->nc.decoding_hash)
171                 goto err;
172 
173         batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
174                                    &batadv_nc_decoding_hash_lock_class_key);
175 
176         INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker);
177         batadv_nc_start_timer(bat_priv);
178 
179         batadv_tvlv_handler_register(bat_priv, batadv_nc_tvlv_ogm_handler_v1,
180                                      NULL, BATADV_TVLV_NC, 1,
181                                      BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
182         batadv_nc_tvlv_container_update(bat_priv);
183         return 0;
184 
185 err:
186         return -ENOMEM;
187 }
188 
189 /**
190  * batadv_nc_init_bat_priv() - initialise the nc specific bat_priv variables
191  * @bat_priv: the bat priv with all the soft interface information
192  */
193 void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv)
194 {
195         atomic_set(&bat_priv->network_coding, 0);
196         bat_priv->nc.min_tq = 200;
197         bat_priv->nc.max_fwd_delay = 10;
198         bat_priv->nc.max_buffer_time = 200;
199 }
200 
201 /**
202  * batadv_nc_init_orig() - initialise the nc fields of an orig_node
203  * @orig_node: the orig_node which is going to be initialised
204  */
205 void batadv_nc_init_orig(struct batadv_orig_node *orig_node)
206 {
207         INIT_LIST_HEAD(&orig_node->in_coding_list);
208         INIT_LIST_HEAD(&orig_node->out_coding_list);
209         spin_lock_init(&orig_node->in_coding_list_lock);
210         spin_lock_init(&orig_node->out_coding_list_lock);
211 }
212 
213 /**
214  * batadv_nc_node_release() - release nc_node from lists and queue for free
215  *  after rcu grace period
216  * @ref: kref pointer of the nc_node
217  */
218 static void batadv_nc_node_release(struct kref *ref)
219 {
220         struct batadv_nc_node *nc_node;
221 
222         nc_node = container_of(ref, struct batadv_nc_node, refcount);
223 
224         batadv_orig_node_put(nc_node->orig_node);
225         kfree_rcu(nc_node, rcu);
226 }
227 
228 /**
229  * batadv_nc_node_put() - decrement the nc_node refcounter and possibly
230  *  release it
231  * @nc_node: nc_node to be free'd
232  */
233 static void batadv_nc_node_put(struct batadv_nc_node *nc_node)
234 {
235         kref_put(&nc_node->refcount, batadv_nc_node_release);
236 }
237 
238 /**
239  * batadv_nc_path_release() - release nc_path from lists and queue for free
240  *  after rcu grace period
241  * @ref: kref pointer of the nc_path
242  */
243 static void batadv_nc_path_release(struct kref *ref)
244 {
245         struct batadv_nc_path *nc_path;
246 
247         nc_path = container_of(ref, struct batadv_nc_path, refcount);
248 
249         kfree_rcu(nc_path, rcu);
250 }
251 
252 /**
253  * batadv_nc_path_put() - decrement the nc_path refcounter and possibly
254  *  release it
255  * @nc_path: nc_path to be free'd
256  */
257 static void batadv_nc_path_put(struct batadv_nc_path *nc_path)
258 {
259         kref_put(&nc_path->refcount, batadv_nc_path_release);
260 }
261 
262 /**
263  * batadv_nc_packet_free() - frees nc packet
264  * @nc_packet: the nc packet to free
265  * @dropped: whether the packet is freed because is is dropped
266  */
267 static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet,
268                                   bool dropped)
269 {
270         if (dropped)
271                 kfree_skb(nc_packet->skb);
272         else
273                 consume_skb(nc_packet->skb);
274 
275         batadv_nc_path_put(nc_packet->nc_path);
276         kfree(nc_packet);
277 }
278 
279 /**
280  * batadv_nc_to_purge_nc_node() - checks whether an nc node has to be purged
281  * @bat_priv: the bat priv with all the soft interface information
282  * @nc_node: the nc node to check
283  *
284  * Return: true if the entry has to be purged now, false otherwise
285  */
286 static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv,
287                                        struct batadv_nc_node *nc_node)
288 {
289         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
290                 return true;
291 
292         return batadv_has_timed_out(nc_node->last_seen, BATADV_NC_NODE_TIMEOUT);
293 }
294 
295 /**
296  * batadv_nc_to_purge_nc_path_coding() - checks whether an nc path has timed out
297  * @bat_priv: the bat priv with all the soft interface information
298  * @nc_path: the nc path to check
299  *
300  * Return: true if the entry has to be purged now, false otherwise
301  */
302 static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv,
303                                               struct batadv_nc_path *nc_path)
304 {
305         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
306                 return true;
307 
308         /* purge the path when no packets has been added for 10 times the
309          * max_fwd_delay time
310          */
311         return batadv_has_timed_out(nc_path->last_valid,
312                                     bat_priv->nc.max_fwd_delay * 10);
313 }
314 
315 /**
316  * batadv_nc_to_purge_nc_path_decoding() - checks whether an nc path has timed
317  *  out
318  * @bat_priv: the bat priv with all the soft interface information
319  * @nc_path: the nc path to check
320  *
321  * Return: true if the entry has to be purged now, false otherwise
322  */
323 static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv,
324                                                 struct batadv_nc_path *nc_path)
325 {
326         if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
327                 return true;
328 
329         /* purge the path when no packets has been added for 10 times the
330          * max_buffer time
331          */
332         return batadv_has_timed_out(nc_path->last_valid,
333                                     bat_priv->nc.max_buffer_time * 10);
334 }
335 
336 /**
337  * batadv_nc_purge_orig_nc_nodes() - go through list of nc nodes and purge stale
338  *  entries
339  * @bat_priv: the bat priv with all the soft interface information
340  * @list: list of nc nodes
341  * @lock: nc node list lock
342  * @to_purge: function in charge to decide whether an entry has to be purged or
343  *            not. This function takes the nc node as argument and has to return
344  *            a boolean value: true if the entry has to be deleted, false
345  *            otherwise
346  */
347 static void
348 batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv,
349                               struct list_head *list,
350                               spinlock_t *lock,
351                               bool (*to_purge)(struct batadv_priv *,
352                                                struct batadv_nc_node *))
353 {
354         struct batadv_nc_node *nc_node, *nc_node_tmp;
355 
356         /* For each nc_node in list */
357         spin_lock_bh(lock);
358         list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) {
359                 /* if an helper function has been passed as parameter,
360                  * ask it if the entry has to be purged or not
361                  */
362                 if (to_purge && !to_purge(bat_priv, nc_node))
363                         continue;
364 
365                 batadv_dbg(BATADV_DBG_NC, bat_priv,
366                            "Removing nc_node %pM -> %pM\n",
367                            nc_node->addr, nc_node->orig_node->orig);
368                 list_del_rcu(&nc_node->list);
369                 batadv_nc_node_put(nc_node);
370         }
371         spin_unlock_bh(lock);
372 }
373 
374 /**
375  * batadv_nc_purge_orig() - purges all nc node data attached of the given
376  *  originator
377  * @bat_priv: the bat priv with all the soft interface information
378  * @orig_node: orig_node with the nc node entries to be purged
379  * @to_purge: function in charge to decide whether an entry has to be purged or
380  *            not. This function takes the nc node as argument and has to return
381  *            a boolean value: true is the entry has to be deleted, false
382  *            otherwise
383  */
384 void batadv_nc_purge_orig(struct batadv_priv *bat_priv,
385                           struct batadv_orig_node *orig_node,
386                           bool (*to_purge)(struct batadv_priv *,
387                                            struct batadv_nc_node *))
388 {
389         /* Check ingoing nc_node's of this orig_node */
390         batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->in_coding_list,
391                                       &orig_node->in_coding_list_lock,
392                                       to_purge);
393 
394         /* Check outgoing nc_node's of this orig_node */
395         batadv_nc_purge_orig_nc_nodes(bat_priv, &orig_node->out_coding_list,
396                                       &orig_node->out_coding_list_lock,
397                                       to_purge);
398 }
399 
400 /**
401  * batadv_nc_purge_orig_hash() - traverse entire originator hash to check if
402  *  they have timed out nc nodes
403  * @bat_priv: the bat priv with all the soft interface information
404  */
405 static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv)
406 {
407         struct batadv_hashtable *hash = bat_priv->orig_hash;
408         struct hlist_head *head;
409         struct batadv_orig_node *orig_node;
410         u32 i;
411 
412         if (!hash)
413                 return;
414 
415         /* For each orig_node */
416         for (i = 0; i < hash->size; i++) {
417                 head = &hash->table[i];
418 
419                 rcu_read_lock();
420                 hlist_for_each_entry_rcu(orig_node, head, hash_entry)
421                         batadv_nc_purge_orig(bat_priv, orig_node,
422                                              batadv_nc_to_purge_nc_node);
423                 rcu_read_unlock();
424         }
425 }
426 
427 /**
428  * batadv_nc_purge_paths() - traverse all nc paths part of the hash and remove
429  *  unused ones
430  * @bat_priv: the bat priv with all the soft interface information
431  * @hash: hash table containing the nc paths to check
432  * @to_purge: function in charge to decide whether an entry has to be purged or
433  *            not. This function takes the nc node as argument and has to return
434  *            a boolean value: true is the entry has to be deleted, false
435  *            otherwise
436  */
437 static void batadv_nc_purge_paths(struct batadv_priv *bat_priv,
438                                   struct batadv_hashtable *hash,
439                                   bool (*to_purge)(struct batadv_priv *,
440                                                    struct batadv_nc_path *))
441 {
442         struct hlist_head *head;
443         struct hlist_node *node_tmp;
444         struct batadv_nc_path *nc_path;
445         spinlock_t *lock; /* Protects lists in hash */
446         u32 i;
447 
448         for (i = 0; i < hash->size; i++) {
449                 head = &hash->table[i];
450                 lock = &hash->list_locks[i];
451 
452                 /* For each nc_path in this bin */
453                 spin_lock_bh(lock);
454                 hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) {
455                         /* if an helper function has been passed as parameter,
456                          * ask it if the entry has to be purged or not
457                          */
458                         if (to_purge && !to_purge(bat_priv, nc_path))
459                                 continue;
460 
461                         /* purging an non-empty nc_path should never happen, but
462                          * is observed under high CPU load. Delay the purging
463                          * until next iteration to allow the packet_list to be
464                          * emptied first.
465                          */
466                         if (!unlikely(list_empty(&nc_path->packet_list))) {
467                                 net_ratelimited_function(printk,
468                                                          KERN_WARNING
469                                                          "Skipping free of non-empty nc_path (%pM -> %pM)!\n",
470                                                          nc_path->prev_hop,
471                                                          nc_path->next_hop);
472                                 continue;
473                         }
474 
475                         /* nc_path is unused, so remove it */
476                         batadv_dbg(BATADV_DBG_NC, bat_priv,
477                                    "Remove nc_path %pM -> %pM\n",
478                                    nc_path->prev_hop, nc_path->next_hop);
479                         hlist_del_rcu(&nc_path->hash_entry);
480                         batadv_nc_path_put(nc_path);
481                 }
482                 spin_unlock_bh(lock);
483         }
484 }
485 
486 /**
487  * batadv_nc_hash_key_gen() - computes the nc_path hash key
488  * @key: buffer to hold the final hash key
489  * @src: source ethernet mac address going into the hash key
490  * @dst: destination ethernet mac address going into the hash key
491  */
492 static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src,
493                                    const char *dst)
494 {
495         memcpy(key->prev_hop, src, sizeof(key->prev_hop));
496         memcpy(key->next_hop, dst, sizeof(key->next_hop));
497 }
498 
499 /**
500  * batadv_nc_hash_choose() - compute the hash value for an nc path
501  * @data: data to hash
502  * @size: size of the hash table
503  *
504  * Return: the selected index in the hash table for the given data.
505  */
506 static u32 batadv_nc_hash_choose(const void *data, u32 size)
507 {
508         const struct batadv_nc_path *nc_path = data;
509         u32 hash = 0;
510 
511         hash = jhash(&nc_path->prev_hop, sizeof(nc_path->prev_hop), hash);
512         hash = jhash(&nc_path->next_hop, sizeof(nc_path->next_hop), hash);
513 
514         return hash % size;
515 }
516 
517 /**
518  * batadv_nc_hash_compare() - comparing function used in the network coding hash
519  *  tables
520  * @node: node in the local table
521  * @data2: second object to compare the node to
522  *
523  * Return: true if the two entry are the same, false otherwise
524  */
525 static bool batadv_nc_hash_compare(const struct hlist_node *node,
526                                    const void *data2)
527 {
528         const struct batadv_nc_path *nc_path1, *nc_path2;
529 
530         nc_path1 = container_of(node, struct batadv_nc_path, hash_entry);
531         nc_path2 = data2;
532 
533         /* Return 1 if the two keys are identical */
534         if (!batadv_compare_eth(nc_path1->prev_hop, nc_path2->prev_hop))
535                 return false;
536 
537         if (!batadv_compare_eth(nc_path1->next_hop, nc_path2->next_hop))
538                 return false;
539 
540         return true;
541 }
542 
543 /**
544  * batadv_nc_hash_find() - search for an existing nc path and return it
545  * @hash: hash table containing the nc path
546  * @data: search key
547  *
548  * Return: the nc_path if found, NULL otherwise.
549  */
550 static struct batadv_nc_path *
551 batadv_nc_hash_find(struct batadv_hashtable *hash,
552                     void *data)
553 {
554         struct hlist_head *head;
555         struct batadv_nc_path *nc_path, *nc_path_tmp = NULL;
556         int index;
557 
558         if (!hash)
559                 return NULL;
560 
561         index = batadv_nc_hash_choose(data, hash->size);
562         head = &hash->table[index];
563 
564         rcu_read_lock();
565         hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
566                 if (!batadv_nc_hash_compare(&nc_path->hash_entry, data))
567                         continue;
568 
569                 if (!kref_get_unless_zero(&nc_path->refcount))
570                         continue;
571 
572                 nc_path_tmp = nc_path;
573                 break;
574         }
575         rcu_read_unlock();
576 
577         return nc_path_tmp;
578 }
579 
580 /**
581  * batadv_nc_send_packet() - send non-coded packet and free nc_packet struct
582  * @nc_packet: the nc packet to send
583  */
584 static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet)
585 {
586         batadv_send_unicast_skb(nc_packet->skb, nc_packet->neigh_node);
587         nc_packet->skb = NULL;
588         batadv_nc_packet_free(nc_packet, false);
589 }
590 
591 /**
592  * batadv_nc_sniffed_purge() - Checks timestamp of given sniffed nc_packet.
593  * @bat_priv: the bat priv with all the soft interface information
594  * @nc_path: the nc path the packet belongs to
595  * @nc_packet: the nc packet to be checked
596  *
597  * Checks whether the given sniffed (overheard) nc_packet has hit its buffering
598  * timeout. If so, the packet is no longer kept and the entry deleted from the
599  * queue. Has to be called with the appropriate locks.
600  *
601  * Return: false as soon as the entry in the fifo queue has not been timed out
602  * yet and true otherwise.
603  */
604 static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
605                                     struct batadv_nc_path *nc_path,
606                                     struct batadv_nc_packet *nc_packet)
607 {
608         unsigned long timeout = bat_priv->nc.max_buffer_time;
609         bool res = false;
610 
611         lockdep_assert_held(&nc_path->packet_list_lock);
612 
613         /* Packets are added to tail, so the remaining packets did not time
614          * out and we can stop processing the current queue
615          */
616         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
617             !batadv_has_timed_out(nc_packet->timestamp, timeout))
618                 goto out;
619 
620         /* purge nc packet */
621         list_del(&nc_packet->list);
622         batadv_nc_packet_free(nc_packet, true);
623 
624         res = true;
625 
626 out:
627         return res;
628 }
629 
630 /**
631  * batadv_nc_fwd_flush() - Checks the timestamp of the given nc packet.
632  * @bat_priv: the bat priv with all the soft interface information
633  * @nc_path: the nc path the packet belongs to
634  * @nc_packet: the nc packet to be checked
635  *
636  * Checks whether the given nc packet has hit its forward timeout. If so, the
637  * packet is no longer delayed, immediately sent and the entry deleted from the
638  * queue. Has to be called with the appropriate locks.
639  *
640  * Return: false as soon as the entry in the fifo queue has not been timed out
641  * yet and true otherwise.
642  */
643 static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
644                                 struct batadv_nc_path *nc_path,
645                                 struct batadv_nc_packet *nc_packet)
646 {
647         unsigned long timeout = bat_priv->nc.max_fwd_delay;
648 
649         lockdep_assert_held(&nc_path->packet_list_lock);
650 
651         /* Packets are added to tail, so the remaining packets did not time
652          * out and we can stop processing the current queue
653          */
654         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE &&
655             !batadv_has_timed_out(nc_packet->timestamp, timeout))
656                 return false;
657 
658         /* Send packet */
659         batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
660         batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
661                            nc_packet->skb->len + ETH_HLEN);
662         list_del(&nc_packet->list);
663         batadv_nc_send_packet(nc_packet);
664 
665         return true;
666 }
667 
668 /**
669  * batadv_nc_process_nc_paths() - traverse given nc packet pool and free timed
670  *  out nc packets
671  * @bat_priv: the bat priv with all the soft interface information
672  * @hash: to be processed hash table
673  * @process_fn: Function called to process given nc packet. Should return true
674  *              to encourage this function to proceed with the next packet.
675  *              Otherwise the rest of the current queue is skipped.
676  */
677 static void
678 batadv_nc_process_nc_paths(struct batadv_priv *bat_priv,
679                            struct batadv_hashtable *hash,
680                            bool (*process_fn)(struct batadv_priv *,
681                                               struct batadv_nc_path *,
682                                               struct batadv_nc_packet *))
683 {
684         struct hlist_head *head;
685         struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
686         struct batadv_nc_path *nc_path;
687         bool ret;
688         int i;
689 
690         if (!hash)
691                 return;
692 
693         /* Loop hash table bins */
694         for (i = 0; i < hash->size; i++) {
695                 head = &hash->table[i];
696 
697                 /* Loop coding paths */
698                 rcu_read_lock();
699                 hlist_for_each_entry_rcu(nc_path, head, hash_entry) {
700                         /* Loop packets */
701                         spin_lock_bh(&nc_path->packet_list_lock);
702                         list_for_each_entry_safe(nc_packet, nc_packet_tmp,
703                                                  &nc_path->packet_list, list) {
704                                 ret = process_fn(bat_priv, nc_path, nc_packet);
705                                 if (!ret)
706                                         break;
707                         }
708                         spin_unlock_bh(&nc_path->packet_list_lock);
709                 }
710                 rcu_read_unlock();
711         }
712 }
713 
714 /**
715  * batadv_nc_worker() - periodic task for house keeping related to network
716  *  coding
717  * @work: kernel work struct
718  */
719 static void batadv_nc_worker(struct work_struct *work)
720 {
721         struct delayed_work *delayed_work;
722         struct batadv_priv_nc *priv_nc;
723         struct batadv_priv *bat_priv;
724         unsigned long timeout;
725 
726         delayed_work = to_delayed_work(work);
727         priv_nc = container_of(delayed_work, struct batadv_priv_nc, work);
728         bat_priv = container_of(priv_nc, struct batadv_priv, nc);
729 
730         batadv_nc_purge_orig_hash(bat_priv);
731         batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash,
732                               batadv_nc_to_purge_nc_path_coding);
733         batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash,
734                               batadv_nc_to_purge_nc_path_decoding);
735 
736         timeout = bat_priv->nc.max_fwd_delay;
737 
738         if (batadv_has_timed_out(bat_priv->nc.timestamp_fwd_flush, timeout)) {
739                 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.coding_hash,
740                                            batadv_nc_fwd_flush);
741                 bat_priv->nc.timestamp_fwd_flush = jiffies;
742         }
743 
744         if (batadv_has_timed_out(bat_priv->nc.timestamp_sniffed_purge,
745                                  bat_priv->nc.max_buffer_time)) {
746                 batadv_nc_process_nc_paths(bat_priv, bat_priv->nc.decoding_hash,
747                                            batadv_nc_sniffed_purge);
748                 bat_priv->nc.timestamp_sniffed_purge = jiffies;
749         }
750 
751         /* Schedule a new check */
752         batadv_nc_start_timer(bat_priv);
753 }
754 
755 /**
756  * batadv_can_nc_with_orig() - checks whether the given orig node is suitable
757  *  for coding or not
758  * @bat_priv: the bat priv with all the soft interface information
759  * @orig_node: neighboring orig node which may be used as nc candidate
760  * @ogm_packet: incoming ogm packet also used for the checks
761  *
762  * Return: true if:
763  *  1) The OGM must have the most recent sequence number.
764  *  2) The TTL must be decremented by one and only one.
765  *  3) The OGM must be received from the first hop from orig_node.
766  *  4) The TQ value of the OGM must be above bat_priv->nc.min_tq.
767  */
768 static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv,
769                                     struct batadv_orig_node *orig_node,
770                                     struct batadv_ogm_packet *ogm_packet)
771 {
772         struct batadv_orig_ifinfo *orig_ifinfo;
773         u32 last_real_seqno;
774         u8 last_ttl;
775 
776         orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT);
777         if (!orig_ifinfo)
778                 return false;
779 
780         last_ttl = orig_ifinfo->last_ttl;
781         last_real_seqno = orig_ifinfo->last_real_seqno;
782         batadv_orig_ifinfo_put(orig_ifinfo);
783 
784         if (last_real_seqno != ntohl(ogm_packet->seqno))
785                 return false;
786         if (last_ttl != ogm_packet->ttl + 1)
787                 return false;
788         if (!batadv_compare_eth(ogm_packet->orig, ogm_packet->prev_sender))
789                 return false;
790         if (ogm_packet->tq < bat_priv->nc.min_tq)
791                 return false;
792 
793         return true;
794 }
795 
796 /**
797  * batadv_nc_find_nc_node() - search for an existing nc node and return it
798  * @orig_node: orig node originating the ogm packet
799  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
800  *  (can be equal to orig_node)
801  * @in_coding: traverse incoming or outgoing network coding list
802  *
803  * Return: the nc_node if found, NULL otherwise.
804  */
805 static struct batadv_nc_node *
806 batadv_nc_find_nc_node(struct batadv_orig_node *orig_node,
807                        struct batadv_orig_node *orig_neigh_node,
808                        bool in_coding)
809 {
810         struct batadv_nc_node *nc_node, *nc_node_out = NULL;
811         struct list_head *list;
812 
813         if (in_coding)
814                 list = &orig_neigh_node->in_coding_list;
815         else
816                 list = &orig_neigh_node->out_coding_list;
817 
818         /* Traverse list of nc_nodes to orig_node */
819         rcu_read_lock();
820         list_for_each_entry_rcu(nc_node, list, list) {
821                 if (!batadv_compare_eth(nc_node->addr, orig_node->orig))
822                         continue;
823 
824                 if (!kref_get_unless_zero(&nc_node->refcount))
825                         continue;
826 
827                 /* Found a match */
828                 nc_node_out = nc_node;
829                 break;
830         }
831         rcu_read_unlock();
832 
833         return nc_node_out;
834 }
835 
836 /**
837  * batadv_nc_get_nc_node() - retrieves an nc node or creates the entry if it was
838  *  not found
839  * @bat_priv: the bat priv with all the soft interface information
840  * @orig_node: orig node originating the ogm packet
841  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
842  *  (can be equal to orig_node)
843  * @in_coding: traverse incoming or outgoing network coding list
844  *
845  * Return: the nc_node if found or created, NULL in case of an error.
846  */
847 static struct batadv_nc_node *
848 batadv_nc_get_nc_node(struct batadv_priv *bat_priv,
849                       struct batadv_orig_node *orig_node,
850                       struct batadv_orig_node *orig_neigh_node,
851                       bool in_coding)
852 {
853         struct batadv_nc_node *nc_node;
854         spinlock_t *lock; /* Used to lock list selected by "int in_coding" */
855         struct list_head *list;
856 
857         /* Select ingoing or outgoing coding node */
858         if (in_coding) {
859                 lock = &orig_neigh_node->in_coding_list_lock;
860                 list = &orig_neigh_node->in_coding_list;
861         } else {
862                 lock = &orig_neigh_node->out_coding_list_lock;
863                 list = &orig_neigh_node->out_coding_list;
864         }
865 
866         spin_lock_bh(lock);
867 
868         /* Check if nc_node is already added */
869         nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding);
870 
871         /* Node found */
872         if (nc_node)
873                 goto unlock;
874 
875         nc_node = kzalloc(sizeof(*nc_node), GFP_ATOMIC);
876         if (!nc_node)
877                 goto unlock;
878 
879         /* Initialize nc_node */
880         INIT_LIST_HEAD(&nc_node->list);
881         kref_init(&nc_node->refcount);
882         ether_addr_copy(nc_node->addr, orig_node->orig);
883         kref_get(&orig_neigh_node->refcount);
884         nc_node->orig_node = orig_neigh_node;
885 
886         batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n",
887                    nc_node->addr, nc_node->orig_node->orig);
888 
889         /* Add nc_node to orig_node */
890         kref_get(&nc_node->refcount);
891         list_add_tail_rcu(&nc_node->list, list);
892 
893 unlock:
894         spin_unlock_bh(lock);
895 
896         return nc_node;
897 }
898 
899 /**
900  * batadv_nc_update_nc_node() - updates stored incoming and outgoing nc node
901  *  structs (best called on incoming OGMs)
902  * @bat_priv: the bat priv with all the soft interface information
903  * @orig_node: orig node originating the ogm packet
904  * @orig_neigh_node: neighboring orig node from which we received the ogm packet
905  *  (can be equal to orig_node)
906  * @ogm_packet: incoming ogm packet
907  * @is_single_hop_neigh: orig_node is a single hop neighbor
908  */
909 void batadv_nc_update_nc_node(struct batadv_priv *bat_priv,
910                               struct batadv_orig_node *orig_node,
911                               struct batadv_orig_node *orig_neigh_node,
912                               struct batadv_ogm_packet *ogm_packet,
913                               int is_single_hop_neigh)
914 {
915         struct batadv_nc_node *in_nc_node = NULL;
916         struct batadv_nc_node *out_nc_node = NULL;
917 
918         /* Check if network coding is enabled */
919         if (!atomic_read(&bat_priv->network_coding))
920                 goto out;
921 
922         /* check if orig node is network coding enabled */
923         if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities))
924                 goto out;
925 
926         /* accept ogms from 'good' neighbors and single hop neighbors */
927         if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) &&
928             !is_single_hop_neigh)
929                 goto out;
930 
931         /* Add orig_node as in_nc_node on hop */
932         in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node,
933                                            orig_neigh_node, true);
934         if (!in_nc_node)
935                 goto out;
936 
937         in_nc_node->last_seen = jiffies;
938 
939         /* Add hop as out_nc_node on orig_node */
940         out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_neigh_node,
941                                             orig_node, false);
942         if (!out_nc_node)
943                 goto out;
944 
945         out_nc_node->last_seen = jiffies;
946 
947 out:
948         if (in_nc_node)
949                 batadv_nc_node_put(in_nc_node);
950         if (out_nc_node)
951                 batadv_nc_node_put(out_nc_node);
952 }
953 
954 /**
955  * batadv_nc_get_path() - get existing nc_path or allocate a new one
956  * @bat_priv: the bat priv with all the soft interface information
957  * @hash: hash table containing the nc path
958  * @src: ethernet source address - first half of the nc path search key
959  * @dst: ethernet destination address - second half of the nc path search key
960  *
961  * Return: pointer to nc_path if the path was found or created, returns NULL
962  * on error.
963  */
964 static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv,
965                                                  struct batadv_hashtable *hash,
966                                                  u8 *src,
967                                                  u8 *dst)
968 {
969         int hash_added;
970         struct batadv_nc_path *nc_path, nc_path_key;
971 
972         batadv_nc_hash_key_gen(&nc_path_key, src, dst);
973 
974         /* Search for existing nc_path */
975         nc_path = batadv_nc_hash_find(hash, (void *)&nc_path_key);
976 
977         if (nc_path) {
978                 /* Set timestamp to delay removal of nc_path */
979                 nc_path->last_valid = jiffies;
980                 return nc_path;
981         }
982 
983         /* No existing nc_path was found; create a new */
984         nc_path = kzalloc(sizeof(*nc_path), GFP_ATOMIC);
985 
986         if (!nc_path)
987                 return NULL;
988 
989         /* Initialize nc_path */
990         INIT_LIST_HEAD(&nc_path->packet_list);
991         spin_lock_init(&nc_path->packet_list_lock);
992         kref_init(&nc_path->refcount);
993         nc_path->last_valid = jiffies;
994         ether_addr_copy(nc_path->next_hop, dst);
995         ether_addr_copy(nc_path->prev_hop, src);
996 
997         batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n",
998                    nc_path->prev_hop,
999                    nc_path->next_hop);
1000 
1001         /* Add nc_path to hash table */
1002         kref_get(&nc_path->refcount);
1003         hash_added = batadv_hash_add(hash, batadv_nc_hash_compare,
1004                                      batadv_nc_hash_choose, &nc_path_key,
1005                                      &nc_path->hash_entry);
1006 
1007         if (hash_added < 0) {
1008                 kfree(nc_path);
1009                 return NULL;
1010         }
1011 
1012         return nc_path;
1013 }
1014 
1015 /**
1016  * batadv_nc_random_weight_tq() - scale the receivers TQ-value to avoid unfair
1017  *  selection of a receiver with slightly lower TQ than the other
1018  * @tq: to be weighted tq value
1019  *
1020  * Return: scaled tq value
1021  */
1022 static u8 batadv_nc_random_weight_tq(u8 tq)
1023 {
1024         u8 rand_val, rand_tq;
1025 
1026         get_random_bytes(&rand_val, sizeof(rand_val));
1027 
1028         /* randomize the estimated packet loss (max TQ - estimated TQ) */
1029         rand_tq = rand_val * (BATADV_TQ_MAX_VALUE - tq);
1030 
1031         /* normalize the randomized packet loss */
1032         rand_tq /= BATADV_TQ_MAX_VALUE;
1033 
1034         /* convert to (randomized) estimated tq again */
1035         return BATADV_TQ_MAX_VALUE - rand_tq;
1036 }
1037 
1038 /**
1039  * batadv_nc_memxor() - XOR destination with source
1040  * @dst: byte array to XOR into
1041  * @src: byte array to XOR from
1042  * @len: length of destination array
1043  */
1044 static void batadv_nc_memxor(char *dst, const char *src, unsigned int len)
1045 {
1046         unsigned int i;
1047 
1048         for (i = 0; i < len; ++i)
1049                 dst[i] ^= src[i];
1050 }
1051 
1052 /**
1053  * batadv_nc_code_packets() - code a received unicast_packet with an nc packet
1054  *  into a coded_packet and send it
1055  * @bat_priv: the bat priv with all the soft interface information
1056  * @skb: data skb to forward
1057  * @ethhdr: pointer to the ethernet header inside the skb
1058  * @nc_packet: structure containing the packet to the skb can be coded with
1059  * @neigh_node: next hop to forward packet to
1060  *
1061  * Return: true if both packets are consumed, false otherwise.
1062  */
1063 static bool batadv_nc_code_packets(struct batadv_priv *bat_priv,
1064                                    struct sk_buff *skb,
1065                                    struct ethhdr *ethhdr,
1066                                    struct batadv_nc_packet *nc_packet,
1067                                    struct batadv_neigh_node *neigh_node)
1068 {
1069         u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp;
1070         struct sk_buff *skb_dest, *skb_src;
1071         struct batadv_unicast_packet *packet1;
1072         struct batadv_unicast_packet *packet2;
1073         struct batadv_coded_packet *coded_packet;
1074         struct batadv_neigh_node *neigh_tmp, *router_neigh, *first_dest;
1075         struct batadv_neigh_node *router_coding = NULL, *second_dest;
1076         struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL;
1077         struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL;
1078         u8 *first_source, *second_source;
1079         __be32 packet_id1, packet_id2;
1080         size_t count;
1081         bool res = false;
1082         int coding_len;
1083         int unicast_size = sizeof(*packet1);
1084         int coded_size = sizeof(*coded_packet);
1085         int header_add = coded_size - unicast_size;
1086 
1087         /* TODO: do we need to consider the outgoing interface for
1088          * coded packets?
1089          */
1090         router_neigh = batadv_orig_router_get(neigh_node->orig_node,
1091                                               BATADV_IF_DEFAULT);
1092         if (!router_neigh)
1093                 goto out;
1094 
1095         router_neigh_ifinfo = batadv_neigh_ifinfo_get(router_neigh,
1096                                                       BATADV_IF_DEFAULT);
1097         if (!router_neigh_ifinfo)
1098                 goto out;
1099 
1100         neigh_tmp = nc_packet->neigh_node;
1101         router_coding = batadv_orig_router_get(neigh_tmp->orig_node,
1102                                                BATADV_IF_DEFAULT);
1103         if (!router_coding)
1104                 goto out;
1105 
1106         router_coding_ifinfo = batadv_neigh_ifinfo_get(router_coding,
1107                                                        BATADV_IF_DEFAULT);
1108         if (!router_coding_ifinfo)
1109                 goto out;
1110 
1111         tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg;
1112         tq_weighted_neigh = batadv_nc_random_weight_tq(tq_tmp);
1113         tq_tmp = router_coding_ifinfo->bat_iv.tq_avg;
1114         tq_weighted_coding = batadv_nc_random_weight_tq(tq_tmp);
1115 
1116         /* Select one destination for the MAC-header dst-field based on
1117          * weighted TQ-values.
1118          */
1119         if (tq_weighted_neigh >= tq_weighted_coding) {
1120                 /* Destination from nc_packet is selected for MAC-header */
1121                 first_dest = nc_packet->neigh_node;
1122                 first_source = nc_packet->nc_path->prev_hop;
1123                 second_dest = neigh_node;
1124                 second_source = ethhdr->h_source;
1125                 packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1126                 packet2 = (struct batadv_unicast_packet *)skb->data;
1127                 packet_id1 = nc_packet->packet_id;
1128                 packet_id2 = batadv_skb_crc32(skb,
1129                                               skb->data + sizeof(*packet2));
1130         } else {
1131                 /* Destination for skb is selected for MAC-header */
1132                 first_dest = neigh_node;
1133                 first_source = ethhdr->h_source;
1134                 second_dest = nc_packet->neigh_node;
1135                 second_source = nc_packet->nc_path->prev_hop;
1136                 packet1 = (struct batadv_unicast_packet *)skb->data;
1137                 packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data;
1138                 packet_id1 = batadv_skb_crc32(skb,
1139                                               skb->data + sizeof(*packet1));
1140                 packet_id2 = nc_packet->packet_id;
1141         }
1142 
1143         /* Instead of zero padding the smallest data buffer, we
1144          * code into the largest.
1145          */
1146         if (skb->len <= nc_packet->skb->len) {
1147                 skb_dest = nc_packet->skb;
1148                 skb_src = skb;
1149         } else {
1150                 skb_dest = skb;
1151                 skb_src = nc_packet->skb;
1152         }
1153 
1154         /* coding_len is used when decoding the packet shorter packet */
1155         coding_len = skb_src->len - unicast_size;
1156 
1157         if (skb_linearize(skb_dest) < 0 || skb_linearize(skb_src) < 0)
1158                 goto out;
1159 
1160         skb_push(skb_dest, header_add);
1161 
1162         coded_packet = (struct batadv_coded_packet *)skb_dest->data;
1163         skb_reset_mac_header(skb_dest);
1164 
1165         coded_packet->packet_type = BATADV_CODED;
1166         coded_packet->version = BATADV_COMPAT_VERSION;
1167         coded_packet->ttl = packet1->ttl;
1168 
1169         /* Info about first unicast packet */
1170         ether_addr_copy(coded_packet->first_source, first_source);
1171         ether_addr_copy(coded_packet->first_orig_dest, packet1->dest);
1172         coded_packet->first_crc = packet_id1;
1173         coded_packet->first_ttvn = packet1->ttvn;
1174 
1175         /* Info about second unicast packet */
1176         ether_addr_copy(coded_packet->second_dest, second_dest->addr);
1177         ether_addr_copy(coded_packet->second_source, second_source);
1178         ether_addr_copy(coded_packet->second_orig_dest, packet2->dest);
1179         coded_packet->second_crc = packet_id2;
1180         coded_packet->second_ttl = packet2->ttl;
1181         coded_packet->second_ttvn = packet2->ttvn;
1182         coded_packet->coded_len = htons(coding_len);
1183 
1184         /* This is where the magic happens: Code skb_src into skb_dest */
1185         batadv_nc_memxor(skb_dest->data + coded_size,
1186                          skb_src->data + unicast_size, coding_len);
1187 
1188         /* Update counters accordingly */
1189         if (BATADV_SKB_CB(skb_src)->decoded &&
1190             BATADV_SKB_CB(skb_dest)->decoded) {
1191                 /* Both packets are recoded */
1192                 count = skb_src->len + ETH_HLEN;
1193                 count += skb_dest->len + ETH_HLEN;
1194                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE, 2);
1195                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES, count);
1196         } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1197                    !BATADV_SKB_CB(skb_dest)->decoded) {
1198                 /* Both packets are newly coded */
1199                 count = skb_src->len + ETH_HLEN;
1200                 count += skb_dest->len + ETH_HLEN;
1201                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE, 2);
1202                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES, count);
1203         } else if (BATADV_SKB_CB(skb_src)->decoded &&
1204                    !BATADV_SKB_CB(skb_dest)->decoded) {
1205                 /* skb_src recoded and skb_dest is newly coded */
1206                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1207                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1208                                    skb_src->len + ETH_HLEN);
1209                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1210                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1211                                    skb_dest->len + ETH_HLEN);
1212         } else if (!BATADV_SKB_CB(skb_src)->decoded &&
1213                    BATADV_SKB_CB(skb_dest)->decoded) {
1214                 /* skb_src is newly coded and skb_dest is recoded */
1215                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE);
1216                 batadv_add_counter(bat_priv, BATADV_CNT_NC_CODE_BYTES,
1217                                    skb_src->len + ETH_HLEN);
1218                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE);
1219                 batadv_add_counter(bat_priv, BATADV_CNT_NC_RECODE_BYTES,
1220                                    skb_dest->len + ETH_HLEN);
1221         }
1222 
1223         /* skb_src is now coded into skb_dest, so free it */
1224         consume_skb(skb_src);
1225 
1226         /* avoid duplicate free of skb from nc_packet */
1227         nc_packet->skb = NULL;
1228         batadv_nc_packet_free(nc_packet, false);
1229 
1230         /* Send the coded packet and return true */
1231         batadv_send_unicast_skb(skb_dest, first_dest);
1232         res = true;
1233 out:
1234         if (router_neigh)
1235                 batadv_neigh_node_put(router_neigh);
1236         if (router_coding)
1237                 batadv_neigh_node_put(router_coding);
1238         if (router_neigh_ifinfo)
1239                 batadv_neigh_ifinfo_put(router_neigh_ifinfo);
1240         if (router_coding_ifinfo)
1241                 batadv_neigh_ifinfo_put(router_coding_ifinfo);
1242         return res;
1243 }
1244 
1245 /**
1246  * batadv_nc_skb_coding_possible() - true if a decoded skb is available at dst.
1247  * @skb: data skb to forward
1248  * @dst: destination mac address of the other skb to code with
1249  * @src: source mac address of skb
1250  *
1251  * Whenever we network code a packet we have to check whether we received it in
1252  * a network coded form. If so, we may not be able to use it for coding because
1253  * some neighbors may also have received (overheard) the packet in the network
1254  * coded form without being able to decode it. It is hard to know which of the
1255  * neighboring nodes was able to decode the packet, therefore we can only
1256  * re-code the packet if the source of the previous encoded packet is involved.
1257  * Since the source encoded the packet we can be certain it has all necessary
1258  * decode information.
1259  *
1260  * Return: true if coding of a decoded packet is allowed.
1261  */
1262 static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src)
1263 {
1264         if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(dst, src))
1265                 return false;
1266         return true;
1267 }
1268 
1269 /**
1270  * batadv_nc_path_search() - Find the coding path matching in_nc_node and
1271  *  out_nc_node to retrieve a buffered packet that can be used for coding.
1272  * @bat_priv: the bat priv with all the soft interface information
1273  * @in_nc_node: pointer to skb next hop's neighbor nc node
1274  * @out_nc_node: pointer to skb source's neighbor nc node
1275  * @skb: data skb to forward
1276  * @eth_dst: next hop mac address of skb
1277  *
1278  * Return: true if coding of a decoded skb is allowed.
1279  */
1280 static struct batadv_nc_packet *
1281 batadv_nc_path_search(struct batadv_priv *bat_priv,
1282                       struct batadv_nc_node *in_nc_node,
1283                       struct batadv_nc_node *out_nc_node,
1284                       struct sk_buff *skb,
1285                       u8 *eth_dst)
1286 {
1287         struct batadv_nc_path *nc_path, nc_path_key;
1288         struct batadv_nc_packet *nc_packet_out = NULL;
1289         struct batadv_nc_packet *nc_packet, *nc_packet_tmp;
1290         struct batadv_hashtable *hash = bat_priv->nc.coding_hash;
1291         int idx;
1292 
1293         if (!hash)
1294                 return NULL;
1295 
1296         /* Create almost path key */
1297         batadv_nc_hash_key_gen(&nc_path_key, in_nc_node->addr,
1298                                out_nc_node->addr);
1299         idx = batadv_nc_hash_choose(&nc_path_key, hash->size);
1300 
1301         /* Check for coding opportunities in this nc_path */
1302         rcu_read_lock();
1303         hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) {
1304                 if (!batadv_compare_eth(nc_path->prev_hop, in_nc_node->addr))
1305                         continue;
1306 
1307                 if (!batadv_compare_eth(nc_path->next_hop, out_nc_node->addr))
1308                         continue;
1309 
1310                 spin_lock_bh(&nc_path->packet_list_lock);
1311                 if (list_empty(&nc_path->packet_list)) {
1312                         spin_unlock_bh(&nc_path->packet_list_lock);
1313                         continue;
1314                 }
1315 
1316                 list_for_each_entry_safe(nc_packet, nc_packet_tmp,
1317                                          &nc_path->packet_list, list) {
1318                         if (!batadv_nc_skb_coding_possible(nc_packet->skb,
1319                                                            eth_dst,
1320                                                            in_nc_node->addr))
1321                                 continue;
1322 
1323                         /* Coding opportunity is found! */
1324                         list_del(&nc_packet->list);
1325                         nc_packet_out = nc_packet;
1326                         break;
1327                 }
1328 
1329                 spin_unlock_bh(&nc_path->packet_list_lock);
1330                 break;
1331         }
1332         rcu_read_unlock();
1333 
1334         return nc_packet_out;
1335 }
1336 
1337 /**
1338  * batadv_nc_skb_src_search() - Loops through the list of neighoring nodes of
1339  *  the skb's sender (may be equal to the originator).
1340  * @bat_priv: the bat priv with all the soft interface information
1341  * @skb: data skb to forward
1342  * @eth_dst: next hop mac address of skb
1343  * @eth_src: source mac address of skb
1344  * @in_nc_node: pointer to skb next hop's neighbor nc node
1345  *
1346  * Return: an nc packet if a suitable coding packet was found, NULL otherwise.
1347  */
1348 static struct batadv_nc_packet *
1349 batadv_nc_skb_src_search(struct batadv_priv *bat_priv,
1350                          struct sk_buff *skb,
1351                          u8 *eth_dst,
1352                          u8 *eth_src,
1353                          struct batadv_nc_node *in_nc_node)
1354 {
1355         struct batadv_orig_node *orig_node;
1356         struct batadv_nc_node *out_nc_node;
1357         struct batadv_nc_packet *nc_packet = NULL;
1358 
1359         orig_node = batadv_orig_hash_find(bat_priv, eth_src);
1360         if (!orig_node)
1361                 return NULL;
1362 
1363         rcu_read_lock();
1364         list_for_each_entry_rcu(out_nc_node,
1365                                 &orig_node->out_coding_list, list) {
1366                 /* Check if the skb is decoded and if recoding is possible */
1367                 if (!batadv_nc_skb_coding_possible(skb,
1368                                                    out_nc_node->addr, eth_src))
1369                         continue;
1370 
1371                 /* Search for an opportunity in this nc_path */
1372                 nc_packet = batadv_nc_path_search(bat_priv, in_nc_node,
1373                                                   out_nc_node, skb, eth_dst);
1374                 if (nc_packet)
1375                         break;
1376         }
1377         rcu_read_unlock();
1378 
1379         batadv_orig_node_put(orig_node);
1380         return nc_packet;
1381 }
1382 
1383 /**
1384  * batadv_nc_skb_store_before_coding() - set the ethernet src and dst of the
1385  *  unicast skb before it is stored for use in later decoding
1386  * @bat_priv: the bat priv with all the soft interface information
1387  * @skb: data skb to store
1388  * @eth_dst_new: new destination mac address of skb
1389  */
1390 static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
1391                                               struct sk_buff *skb,
1392                                               u8 *eth_dst_new)
1393 {
1394         struct ethhdr *ethhdr;
1395 
1396         /* Copy skb header to change the mac header */
1397         skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
1398         if (!skb)
1399                 return;
1400 
1401         /* Set the mac header as if we actually sent the packet uncoded */
1402         ethhdr = eth_hdr(skb);
1403         ether_addr_copy(ethhdr->h_source, ethhdr->h_dest);
1404         ether_addr_copy(ethhdr->h_dest, eth_dst_new);
1405 
1406         /* Set data pointer to MAC header to mimic packets from our tx path */
1407         skb_push(skb, ETH_HLEN);
1408 
1409         /* Add the packet to the decoding packet pool */
1410         batadv_nc_skb_store_for_decoding(bat_priv, skb);
1411 
1412         /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free
1413          * our ref
1414          */
1415         consume_skb(skb);
1416 }
1417 
1418 /**
1419  * batadv_nc_skb_dst_search() - Loops through list of neighboring nodes to dst.
1420  * @skb: data skb to forward
1421  * @neigh_node: next hop to forward packet to
1422  * @ethhdr: pointer to the ethernet header inside the skb
1423  *
1424  * Loops through list of neighboring nodes the next hop has a good connection to
1425  * (receives OGMs with a sufficient quality). We need to find a neighbor of our
1426  * next hop that potentially sent a packet which our next hop also received
1427  * (overheard) and has stored for later decoding.
1428  *
1429  * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1430  */
1431 static bool batadv_nc_skb_dst_search(struct sk_buff *skb,
1432                                      struct batadv_neigh_node *neigh_node,
1433                                      struct ethhdr *ethhdr)
1434 {
1435         struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1436         struct batadv_priv *bat_priv = netdev_priv(netdev);
1437         struct batadv_orig_node *orig_node = neigh_node->orig_node;
1438         struct batadv_nc_node *nc_node;
1439         struct batadv_nc_packet *nc_packet = NULL;
1440 
1441         rcu_read_lock();
1442         list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) {
1443                 /* Search for coding opportunity with this in_nc_node */
1444                 nc_packet = batadv_nc_skb_src_search(bat_priv, skb,
1445                                                      neigh_node->addr,
1446                                                      ethhdr->h_source, nc_node);
1447 
1448                 /* Opportunity was found, so stop searching */
1449                 if (nc_packet)
1450                         break;
1451         }
1452         rcu_read_unlock();
1453 
1454         if (!nc_packet)
1455                 return false;
1456 
1457         /* Save packets for later decoding */
1458         batadv_nc_skb_store_before_coding(bat_priv, skb,
1459                                           neigh_node->addr);
1460         batadv_nc_skb_store_before_coding(bat_priv, nc_packet->skb,
1461                                           nc_packet->neigh_node->addr);
1462 
1463         /* Code and send packets */
1464         if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet,
1465                                    neigh_node))
1466                 return true;
1467 
1468         /* out of mem ? Coding failed - we have to free the buffered packet
1469          * to avoid memleaks. The skb passed as argument will be dealt with
1470          * by the calling function.
1471          */
1472         batadv_nc_send_packet(nc_packet);
1473         return false;
1474 }
1475 
1476 /**
1477  * batadv_nc_skb_add_to_path() - buffer skb for later encoding / decoding
1478  * @skb: skb to add to path
1479  * @nc_path: path to add skb to
1480  * @neigh_node: next hop to forward packet to
1481  * @packet_id: checksum to identify packet
1482  *
1483  * Return: true if the packet was buffered or false in case of an error.
1484  */
1485 static bool batadv_nc_skb_add_to_path(struct sk_buff *skb,
1486                                       struct batadv_nc_path *nc_path,
1487                                       struct batadv_neigh_node *neigh_node,
1488                                       __be32 packet_id)
1489 {
1490         struct batadv_nc_packet *nc_packet;
1491 
1492         nc_packet = kzalloc(sizeof(*nc_packet), GFP_ATOMIC);
1493         if (!nc_packet)
1494                 return false;
1495 
1496         /* Initialize nc_packet */
1497         nc_packet->timestamp = jiffies;
1498         nc_packet->packet_id = packet_id;
1499         nc_packet->skb = skb;
1500         nc_packet->neigh_node = neigh_node;
1501         nc_packet->nc_path = nc_path;
1502 
1503         /* Add coding packet to list */
1504         spin_lock_bh(&nc_path->packet_list_lock);
1505         list_add_tail(&nc_packet->list, &nc_path->packet_list);
1506         spin_unlock_bh(&nc_path->packet_list_lock);
1507 
1508         return true;
1509 }
1510 
1511 /**
1512  * batadv_nc_skb_forward() - try to code a packet or add it to the coding packet
1513  *  buffer
1514  * @skb: data skb to forward
1515  * @neigh_node: next hop to forward packet to
1516  *
1517  * Return: true if the skb was consumed (encoded packet sent) or false otherwise
1518  */
1519 bool batadv_nc_skb_forward(struct sk_buff *skb,
1520                            struct batadv_neigh_node *neigh_node)
1521 {
1522         const struct net_device *netdev = neigh_node->if_incoming->soft_iface;
1523         struct batadv_priv *bat_priv = netdev_priv(netdev);
1524         struct batadv_unicast_packet *packet;
1525         struct batadv_nc_path *nc_path;
1526         struct ethhdr *ethhdr = eth_hdr(skb);
1527         __be32 packet_id;
1528         u8 *payload;
1529 
1530         /* Check if network coding is enabled */
1531         if (!atomic_read(&bat_priv->network_coding))
1532                 goto out;
1533 
1534         /* We only handle unicast packets */
1535         payload = skb_network_header(skb);
1536         packet = (struct batadv_unicast_packet *)payload;
1537         if (packet->packet_type != BATADV_UNICAST)
1538                 goto out;
1539 
1540         /* Try to find a coding opportunity and send the skb if one is found */
1541         if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr))
1542                 return true;
1543 
1544         /* Find or create a nc_path for this src-dst pair */
1545         nc_path = batadv_nc_get_path(bat_priv,
1546                                      bat_priv->nc.coding_hash,
1547                                      ethhdr->h_source,
1548                                      neigh_node->addr);
1549 
1550         if (!nc_path)
1551                 goto out;
1552 
1553         /* Add skb to nc_path */
1554         packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1555         if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id))
1556                 goto free_nc_path;
1557 
1558         /* Packet is consumed */
1559         return true;
1560 
1561 free_nc_path:
1562         batadv_nc_path_put(nc_path);
1563 out:
1564         /* Packet is not consumed */
1565         return false;
1566 }
1567 
1568 /**
1569  * batadv_nc_skb_store_for_decoding() - save a clone of the skb which can be
1570  *  used when decoding coded packets
1571  * @bat_priv: the bat priv with all the soft interface information
1572  * @skb: data skb to store
1573  */
1574 void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv,
1575                                       struct sk_buff *skb)
1576 {
1577         struct batadv_unicast_packet *packet;
1578         struct batadv_nc_path *nc_path;
1579         struct ethhdr *ethhdr = eth_hdr(skb);
1580         __be32 packet_id;
1581         u8 *payload;
1582 
1583         /* Check if network coding is enabled */
1584         if (!atomic_read(&bat_priv->network_coding))
1585                 goto out;
1586 
1587         /* Check for supported packet type */
1588         payload = skb_network_header(skb);
1589         packet = (struct batadv_unicast_packet *)payload;
1590         if (packet->packet_type != BATADV_UNICAST)
1591                 goto out;
1592 
1593         /* Find existing nc_path or create a new */
1594         nc_path = batadv_nc_get_path(bat_priv,
1595                                      bat_priv->nc.decoding_hash,
1596                                      ethhdr->h_source,
1597                                      ethhdr->h_dest);
1598 
1599         if (!nc_path)
1600                 goto out;
1601 
1602         /* Clone skb and adjust skb->data to point at batman header */
1603         skb = skb_clone(skb, GFP_ATOMIC);
1604         if (unlikely(!skb))
1605                 goto free_nc_path;
1606 
1607         if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
1608                 goto free_skb;
1609 
1610         if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN)))
1611                 goto free_skb;
1612 
1613         /* Add skb to nc_path */
1614         packet_id = batadv_skb_crc32(skb, payload + sizeof(*packet));
1615         if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id))
1616                 goto free_skb;
1617 
1618         batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER);
1619         return;
1620 
1621 free_skb:
1622         kfree_skb(skb);
1623 free_nc_path:
1624         batadv_nc_path_put(nc_path);
1625 out:
1626         return;
1627 }
1628 
1629 /**
1630  * batadv_nc_skb_store_sniffed_unicast() - check if a received unicast packet
1631  *  should be saved in the decoding buffer and, if so, store it there
1632  * @bat_priv: the bat priv with all the soft interface information
1633  * @skb: unicast skb to store
1634  */
1635 void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv,
1636                                          struct sk_buff *skb)
1637 {
1638         struct ethhdr *ethhdr = eth_hdr(skb);
1639 
1640         if (batadv_is_my_mac(bat_priv, ethhdr->h_dest))
1641                 return;
1642 
1643         /* Set data pointer to MAC header to mimic packets from our tx path */
1644         skb_push(skb, ETH_HLEN);
1645 
1646         batadv_nc_skb_store_for_decoding(bat_priv, skb);
1647 }
1648 
1649 /**
1650  * batadv_nc_skb_decode_packet() - decode given skb using the decode data stored
1651  *  in nc_packet
1652  * @bat_priv: the bat priv with all the soft interface information
1653  * @skb: unicast skb to decode
1654  * @nc_packet: decode data needed to decode the skb
1655  *
1656  * Return: pointer to decoded unicast packet if the packet was decoded or NULL
1657  * in case of an error.
1658  */
1659 static struct batadv_unicast_packet *
1660 batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
1661                             struct batadv_nc_packet *nc_packet)
1662 {
1663         const int h_size = sizeof(struct batadv_unicast_packet);
1664         const int h_diff = sizeof(struct batadv_coded_packet) - h_size;
1665         struct batadv_unicast_packet *unicast_packet;
1666         struct batadv_coded_packet coded_packet_tmp;
1667         struct ethhdr *ethhdr, ethhdr_tmp;
1668         u8 *orig_dest, ttl, ttvn;
1669         unsigned int coding_len;
1670         int err;
1671 
1672         /* Save headers temporarily */
1673         memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp));
1674         memcpy(&ethhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp));
1675 
1676         if (skb_cow(skb, 0) < 0)
1677                 return NULL;
1678 
1679         if (unlikely(!skb_pull_rcsum(skb, h_diff)))
1680                 return NULL;
1681 
1682         /* Data points to batman header, so set mac header 14 bytes before
1683          * and network to data
1684          */
1685         skb_set_mac_header(skb, -ETH_HLEN);
1686         skb_reset_network_header(skb);
1687 
1688         /* Reconstruct original mac header */
1689         ethhdr = eth_hdr(skb);
1690         *ethhdr = ethhdr_tmp;
1691 
1692         /* Select the correct unicast header information based on the location
1693          * of our mac address in the coded_packet header
1694          */
1695         if (batadv_is_my_mac(bat_priv, coded_packet_tmp.second_dest)) {
1696                 /* If we are the second destination the packet was overheard,
1697                  * so the Ethernet address must be copied to h_dest and
1698                  * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST
1699                  */
1700                 ether_addr_copy(ethhdr->h_dest, coded_packet_tmp.second_dest);
1701                 skb->pkt_type = PACKET_HOST;
1702 
1703                 orig_dest = coded_packet_tmp.second_orig_dest;
1704                 ttl = coded_packet_tmp.second_ttl;
1705                 ttvn = coded_packet_tmp.second_ttvn;
1706         } else {
1707                 orig_dest = coded_packet_tmp.first_orig_dest;
1708                 ttl = coded_packet_tmp.ttl;
1709                 ttvn = coded_packet_tmp.first_ttvn;
1710         }
1711 
1712         coding_len = ntohs(coded_packet_tmp.coded_len);
1713 
1714         if (coding_len > skb->len)
1715                 return NULL;
1716 
1717         /* Here the magic is reversed:
1718          *   extract the missing packet from the received coded packet
1719          */
1720         batadv_nc_memxor(skb->data + h_size,
1721                          nc_packet->skb->data + h_size,
1722                          coding_len);
1723 
1724         /* Resize decoded skb if decoded with larger packet */
1725         if (nc_packet->skb->len > coding_len + h_size) {
1726                 err = pskb_trim_rcsum(skb, coding_len + h_size);
1727                 if (err)
1728                         return NULL;
1729         }
1730 
1731         /* Create decoded unicast packet */
1732         unicast_packet = (struct batadv_unicast_packet *)skb->data;
1733         unicast_packet->packet_type = BATADV_UNICAST;
1734         unicast_packet->version = BATADV_COMPAT_VERSION;
1735         unicast_packet->ttl = ttl;
1736         ether_addr_copy(unicast_packet->dest, orig_dest);
1737         unicast_packet->ttvn = ttvn;
1738 
1739         batadv_nc_packet_free(nc_packet, false);
1740         return unicast_packet;
1741 }
1742 
1743 /**
1744  * batadv_nc_find_decoding_packet() - search through buffered decoding data to
1745  *  find the data needed to decode the coded packet
1746  * @bat_priv: the bat priv with all the soft interface information
1747  * @ethhdr: pointer to the ethernet header inside the coded packet
1748  * @coded: coded packet we try to find decode data for
1749  *
1750  * Return: pointer to nc packet if the needed data was found or NULL otherwise.
1751  */
1752 static struct batadv_nc_packet *
1753 batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv,
1754                                struct ethhdr *ethhdr,
1755                                struct batadv_coded_packet *coded)
1756 {
1757         struct batadv_hashtable *hash = bat_priv->nc.decoding_hash;
1758         struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL;
1759         struct batadv_nc_path *nc_path, nc_path_key;
1760         u8 *dest, *source;
1761         __be32 packet_id;
1762         int index;
1763 
1764         if (!hash)
1765                 return NULL;
1766 
1767         /* Select the correct packet id based on the location of our mac-addr */
1768         dest = ethhdr->h_source;
1769         if (!batadv_is_my_mac(bat_priv, coded->second_dest)) {
1770                 source = coded->second_source;
1771                 packet_id = coded->second_crc;
1772         } else {
1773                 source = coded->first_source;
1774                 packet_id = coded->first_crc;
1775         }
1776 
1777         batadv_nc_hash_key_gen(&nc_path_key, source, dest);
1778         index = batadv_nc_hash_choose(&nc_path_key, hash->size);
1779 
1780         /* Search for matching coding path */
1781         rcu_read_lock();
1782         hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) {
1783                 /* Find matching nc_packet */
1784                 spin_lock_bh(&nc_path->packet_list_lock);
1785                 list_for_each_entry(tmp_nc_packet,
1786                                     &nc_path->packet_list, list) {
1787                         if (packet_id == tmp_nc_packet->packet_id) {
1788                                 list_del(&tmp_nc_packet->list);
1789 
1790                                 nc_packet = tmp_nc_packet;
1791                                 break;
1792                         }
1793                 }
1794                 spin_unlock_bh(&nc_path->packet_list_lock);
1795 
1796                 if (nc_packet)
1797                         break;
1798         }
1799         rcu_read_unlock();
1800 
1801         if (!nc_packet)
1802                 batadv_dbg(BATADV_DBG_NC, bat_priv,
1803                            "No decoding packet found for %u\n", packet_id);
1804 
1805         return nc_packet;
1806 }
1807 
1808 /**
1809  * batadv_nc_recv_coded_packet() - try to decode coded packet and enqueue the
1810  *  resulting unicast packet
1811  * @skb: incoming coded packet
1812  * @recv_if: pointer to interface this packet was received on
1813  *
1814  * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1815  * otherwise.
1816  */
1817 static int batadv_nc_recv_coded_packet(struct sk_buff *skb,
1818                                        struct batadv_hard_iface *recv_if)
1819 {
1820         struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
1821         struct batadv_unicast_packet *unicast_packet;
1822         struct batadv_coded_packet *coded_packet;
1823         struct batadv_nc_packet *nc_packet;
1824         struct ethhdr *ethhdr;
1825         int hdr_size = sizeof(*coded_packet);
1826 
1827         /* Check if network coding is enabled */
1828         if (!atomic_read(&bat_priv->network_coding))
1829                 goto free_skb;
1830 
1831         /* Make sure we can access (and remove) header */
1832         if (unlikely(!pskb_may_pull(skb, hdr_size)))
1833                 goto free_skb;
1834 
1835         coded_packet = (struct batadv_coded_packet *)skb->data;
1836         ethhdr = eth_hdr(skb);
1837 
1838         /* Verify frame is destined for us */
1839         if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest) &&
1840             !batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1841                 goto free_skb;
1842 
1843         /* Update stat counter */
1844         if (batadv_is_my_mac(bat_priv, coded_packet->second_dest))
1845                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED);
1846 
1847         nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr,
1848                                                    coded_packet);
1849         if (!nc_packet) {
1850                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1851                 goto free_skb;
1852         }
1853 
1854         /* Make skb's linear, because decoding accesses the entire buffer */
1855         if (skb_linearize(skb) < 0)
1856                 goto free_nc_packet;
1857 
1858         if (skb_linearize(nc_packet->skb) < 0)
1859                 goto free_nc_packet;
1860 
1861         /* Decode the packet */
1862         unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet);
1863         if (!unicast_packet) {
1864                 batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED);
1865                 goto free_nc_packet;
1866         }
1867 
1868         /* Mark packet as decoded to do correct recoding when forwarding */
1869         BATADV_SKB_CB(skb)->decoded = true;
1870         batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE);
1871         batadv_add_counter(bat_priv, BATADV_CNT_NC_DECODE_BYTES,
1872                            skb->len + ETH_HLEN);
1873         return batadv_recv_unicast_packet(skb, recv_if);
1874 
1875 free_nc_packet:
1876         batadv_nc_packet_free(nc_packet, true);
1877 free_skb:
1878         kfree_skb(skb);
1879 
1880         return NET_RX_DROP;
1881 }
1882 
1883 /**
1884  * batadv_nc_mesh_free() - clean up network coding memory
1885  * @bat_priv: the bat priv with all the soft interface information
1886  */
1887 void batadv_nc_mesh_free(struct batadv_priv *bat_priv)
1888 {
1889         batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_NC, 1);
1890         batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_NC, 1);
1891         cancel_delayed_work_sync(&bat_priv->nc.work);
1892 
1893         batadv_nc_purge_paths(bat_priv, bat_priv->nc.coding_hash, NULL);
1894         batadv_hash_destroy(bat_priv->nc.coding_hash);
1895         batadv_nc_purge_paths(bat_priv, bat_priv->nc.decoding_hash, NULL);
1896         batadv_hash_destroy(bat_priv->nc.decoding_hash);
1897 }
1898 
1899 #ifdef CONFIG_BATMAN_ADV_DEBUGFS
1900 /**
1901  * batadv_nc_nodes_seq_print_text() - print the nc node information
1902  * @seq: seq file to print on
1903  * @offset: not used
1904  *
1905  * Return: always 0
1906  */
1907 int batadv_nc_nodes_seq_print_text(struct seq_file *seq, void *offset)
1908 {
1909         struct net_device *net_dev = (struct net_device *)seq->private;
1910         struct batadv_priv *bat_priv = netdev_priv(net_dev);
1911         struct batadv_hashtable *hash = bat_priv->orig_hash;
1912         struct batadv_hard_iface *primary_if;
1913         struct hlist_head *head;
1914         struct batadv_orig_node *orig_node;
1915         struct batadv_nc_node *nc_node;
1916         int i;
1917 
1918         primary_if = batadv_seq_print_text_primary_if_get(seq);
1919         if (!primary_if)
1920                 goto out;
1921 
1922         /* Traverse list of originators */
1923         for (i = 0; i < hash->size; i++) {
1924                 head = &hash->table[i];
1925 
1926                 /* For each orig_node in this bin */
1927                 rcu_read_lock();
1928                 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
1929                         /* no need to print the orig node if it does not have
1930                          * network coding neighbors
1931                          */
1932                         if (list_empty(&orig_node->in_coding_list) &&
1933                             list_empty(&orig_node->out_coding_list))
1934                                 continue;
1935 
1936                         seq_printf(seq, "Node:      %pM\n", orig_node->orig);
1937 
1938                         seq_puts(seq, " Ingoing:  ");
1939                         /* For each in_nc_node to this orig_node */
1940                         list_for_each_entry_rcu(nc_node,
1941                                                 &orig_node->in_coding_list,
1942                                                 list)
1943                                 seq_printf(seq, "%pM ",
1944                                            nc_node->addr);
1945                         seq_puts(seq, "\n Outgoing: ");
1946                         /* For out_nc_node to this orig_node */
1947                         list_for_each_entry_rcu(nc_node,
1948                                                 &orig_node->out_coding_list,
1949                                                 list)
1950                                 seq_printf(seq, "%pM ",
1951                                            nc_node->addr);
1952                         seq_puts(seq, "\n\n");
1953                 }
1954                 rcu_read_unlock();
1955         }
1956 
1957 out:
1958         if (primary_if)
1959                 batadv_hardif_put(primary_if);
1960         return 0;
1961 }
1962 
1963 /**
1964  * batadv_nc_init_debugfs() - create nc folder and related files in debugfs
1965  * @bat_priv: the bat priv with all the soft interface information
1966  *
1967  * Return: 0 on success or negative error number in case of failure
1968  */
1969 int batadv_nc_init_debugfs(struct batadv_priv *bat_priv)
1970 {
1971         struct dentry *nc_dir, *file;
1972 
1973         nc_dir = debugfs_create_dir("nc", bat_priv->debug_dir);
1974         if (!nc_dir)
1975                 goto out;
1976 
1977         file = debugfs_create_u8("min_tq", 0644, nc_dir, &bat_priv->nc.min_tq);
1978         if (!file)
1979                 goto out;
1980 
1981         file = debugfs_create_u32("max_fwd_delay", 0644, nc_dir,
1982                                   &bat_priv->nc.max_fwd_delay);
1983         if (!file)
1984                 goto out;
1985 
1986         file = debugfs_create_u32("max_buffer_time", 0644, nc_dir,
1987                                   &bat_priv->nc.max_buffer_time);
1988         if (!file)
1989                 goto out;
1990 
1991         return 0;
1992 
1993 out:
1994         return -ENOMEM;
1995 }
1996 #endif
1997 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp