1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* Copyright (C) B.A.T.M.A.N. contributors: |
3 | * |
4 | * Martin Hundebøll, Jeppe Ledet-Pedersen |
5 | */ |
6 | |
7 | #include "network-coding.h" |
8 | #include "main.h" |
9 | |
10 | #include <linux/atomic.h> |
11 | #include <linux/bitops.h> |
12 | #include <linux/byteorder/generic.h> |
13 | #include <linux/compiler.h> |
14 | #include <linux/container_of.h> |
15 | #include <linux/errno.h> |
16 | #include <linux/etherdevice.h> |
17 | #include <linux/gfp.h> |
18 | #include <linux/if_ether.h> |
19 | #include <linux/if_packet.h> |
20 | #include <linux/init.h> |
21 | #include <linux/jhash.h> |
22 | #include <linux/jiffies.h> |
23 | #include <linux/kref.h> |
24 | #include <linux/list.h> |
25 | #include <linux/lockdep.h> |
26 | #include <linux/net.h> |
27 | #include <linux/netdevice.h> |
28 | #include <linux/printk.h> |
29 | #include <linux/random.h> |
30 | #include <linux/rculist.h> |
31 | #include <linux/rcupdate.h> |
32 | #include <linux/skbuff.h> |
33 | #include <linux/slab.h> |
34 | #include <linux/spinlock.h> |
35 | #include <linux/stddef.h> |
36 | #include <linux/string.h> |
37 | #include <linux/workqueue.h> |
38 | #include <uapi/linux/batadv_packet.h> |
39 | |
40 | #include "hash.h" |
41 | #include "log.h" |
42 | #include "originator.h" |
43 | #include "routing.h" |
44 | #include "send.h" |
45 | #include "tvlv.h" |
46 | |
47 | static struct lock_class_key batadv_nc_coding_hash_lock_class_key; |
48 | static struct lock_class_key batadv_nc_decoding_hash_lock_class_key; |
49 | |
50 | static void batadv_nc_worker(struct work_struct *work); |
51 | static int batadv_nc_recv_coded_packet(struct sk_buff *skb, |
52 | struct batadv_hard_iface *recv_if); |
53 | |
54 | /** |
55 | * batadv_nc_init() - one-time initialization for network coding |
56 | * |
57 | * Return: 0 on success or negative error number in case of failure |
58 | */ |
59 | int __init batadv_nc_init(void) |
60 | { |
61 | /* Register our packet type */ |
62 | return batadv_recv_handler_register(packet_type: BATADV_CODED, |
63 | recv_handler: batadv_nc_recv_coded_packet); |
64 | } |
65 | |
66 | /** |
67 | * batadv_nc_start_timer() - initialise the nc periodic worker |
68 | * @bat_priv: the bat priv with all the soft interface information |
69 | */ |
70 | static void batadv_nc_start_timer(struct batadv_priv *bat_priv) |
71 | { |
72 | queue_delayed_work(wq: batadv_event_workqueue, dwork: &bat_priv->nc.work, |
73 | delay: msecs_to_jiffies(m: 10)); |
74 | } |
75 | |
76 | /** |
77 | * batadv_nc_tvlv_container_update() - update the network coding tvlv container |
78 | * after network coding setting change |
79 | * @bat_priv: the bat priv with all the soft interface information |
80 | */ |
81 | static void batadv_nc_tvlv_container_update(struct batadv_priv *bat_priv) |
82 | { |
83 | char nc_mode; |
84 | |
85 | nc_mode = atomic_read(v: &bat_priv->network_coding); |
86 | |
87 | switch (nc_mode) { |
88 | case 0: |
89 | batadv_tvlv_container_unregister(bat_priv, type: BATADV_TVLV_NC, version: 1); |
90 | break; |
91 | case 1: |
92 | batadv_tvlv_container_register(bat_priv, type: BATADV_TVLV_NC, version: 1, |
93 | NULL, tvlv_value_len: 0); |
94 | break; |
95 | } |
96 | } |
97 | |
98 | /** |
99 | * batadv_nc_status_update() - update the network coding tvlv container after |
100 | * network coding setting change |
101 | * @net_dev: the soft interface net device |
102 | */ |
103 | void batadv_nc_status_update(struct net_device *net_dev) |
104 | { |
105 | struct batadv_priv *bat_priv = netdev_priv(dev: net_dev); |
106 | |
107 | batadv_nc_tvlv_container_update(bat_priv); |
108 | } |
109 | |
110 | /** |
111 | * batadv_nc_tvlv_ogm_handler_v1() - process incoming nc tvlv container |
112 | * @bat_priv: the bat priv with all the soft interface information |
113 | * @orig: the orig_node of the ogm |
114 | * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags) |
115 | * @tvlv_value: tvlv buffer containing the gateway data |
116 | * @tvlv_value_len: tvlv buffer length |
117 | */ |
118 | static void batadv_nc_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv, |
119 | struct batadv_orig_node *orig, |
120 | u8 flags, |
121 | void *tvlv_value, u16 tvlv_value_len) |
122 | { |
123 | if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND) |
124 | clear_bit(nr: BATADV_ORIG_CAPA_HAS_NC, addr: &orig->capabilities); |
125 | else |
126 | set_bit(nr: BATADV_ORIG_CAPA_HAS_NC, addr: &orig->capabilities); |
127 | } |
128 | |
129 | /** |
130 | * batadv_nc_mesh_init() - initialise coding hash table and start housekeeping |
131 | * @bat_priv: the bat priv with all the soft interface information |
132 | * |
133 | * Return: 0 on success or negative error number in case of failure |
134 | */ |
135 | int batadv_nc_mesh_init(struct batadv_priv *bat_priv) |
136 | { |
137 | bat_priv->nc.timestamp_fwd_flush = jiffies; |
138 | bat_priv->nc.timestamp_sniffed_purge = jiffies; |
139 | |
140 | if (bat_priv->nc.coding_hash || bat_priv->nc.decoding_hash) |
141 | return 0; |
142 | |
143 | bat_priv->nc.coding_hash = batadv_hash_new(size: 128); |
144 | if (!bat_priv->nc.coding_hash) |
145 | goto err; |
146 | |
147 | batadv_hash_set_lock_class(hash: bat_priv->nc.coding_hash, |
148 | key: &batadv_nc_coding_hash_lock_class_key); |
149 | |
150 | bat_priv->nc.decoding_hash = batadv_hash_new(size: 128); |
151 | if (!bat_priv->nc.decoding_hash) { |
152 | batadv_hash_destroy(hash: bat_priv->nc.coding_hash); |
153 | goto err; |
154 | } |
155 | |
156 | batadv_hash_set_lock_class(hash: bat_priv->nc.decoding_hash, |
157 | key: &batadv_nc_decoding_hash_lock_class_key); |
158 | |
159 | INIT_DELAYED_WORK(&bat_priv->nc.work, batadv_nc_worker); |
160 | batadv_nc_start_timer(bat_priv); |
161 | |
162 | batadv_tvlv_handler_register(bat_priv, optr: batadv_nc_tvlv_ogm_handler_v1, |
163 | NULL, NULL, type: BATADV_TVLV_NC, version: 1, |
164 | flags: BATADV_TVLV_HANDLER_OGM_CIFNOTFND); |
165 | batadv_nc_tvlv_container_update(bat_priv); |
166 | return 0; |
167 | |
168 | err: |
169 | return -ENOMEM; |
170 | } |
171 | |
172 | /** |
173 | * batadv_nc_init_bat_priv() - initialise the nc specific bat_priv variables |
174 | * @bat_priv: the bat priv with all the soft interface information |
175 | */ |
176 | void batadv_nc_init_bat_priv(struct batadv_priv *bat_priv) |
177 | { |
178 | atomic_set(v: &bat_priv->network_coding, i: 0); |
179 | bat_priv->nc.min_tq = 200; |
180 | bat_priv->nc.max_fwd_delay = 10; |
181 | bat_priv->nc.max_buffer_time = 200; |
182 | } |
183 | |
184 | /** |
185 | * batadv_nc_init_orig() - initialise the nc fields of an orig_node |
186 | * @orig_node: the orig_node which is going to be initialised |
187 | */ |
188 | void batadv_nc_init_orig(struct batadv_orig_node *orig_node) |
189 | { |
190 | INIT_LIST_HEAD(list: &orig_node->in_coding_list); |
191 | INIT_LIST_HEAD(list: &orig_node->out_coding_list); |
192 | spin_lock_init(&orig_node->in_coding_list_lock); |
193 | spin_lock_init(&orig_node->out_coding_list_lock); |
194 | } |
195 | |
196 | /** |
197 | * batadv_nc_node_release() - release nc_node from lists and queue for free |
198 | * after rcu grace period |
199 | * @ref: kref pointer of the nc_node |
200 | */ |
201 | static void batadv_nc_node_release(struct kref *ref) |
202 | { |
203 | struct batadv_nc_node *nc_node; |
204 | |
205 | nc_node = container_of(ref, struct batadv_nc_node, refcount); |
206 | |
207 | batadv_orig_node_put(orig_node: nc_node->orig_node); |
208 | kfree_rcu(nc_node, rcu); |
209 | } |
210 | |
211 | /** |
212 | * batadv_nc_node_put() - decrement the nc_node refcounter and possibly |
213 | * release it |
214 | * @nc_node: nc_node to be free'd |
215 | */ |
216 | static void batadv_nc_node_put(struct batadv_nc_node *nc_node) |
217 | { |
218 | if (!nc_node) |
219 | return; |
220 | |
221 | kref_put(kref: &nc_node->refcount, release: batadv_nc_node_release); |
222 | } |
223 | |
224 | /** |
225 | * batadv_nc_path_release() - release nc_path from lists and queue for free |
226 | * after rcu grace period |
227 | * @ref: kref pointer of the nc_path |
228 | */ |
229 | static void batadv_nc_path_release(struct kref *ref) |
230 | { |
231 | struct batadv_nc_path *nc_path; |
232 | |
233 | nc_path = container_of(ref, struct batadv_nc_path, refcount); |
234 | |
235 | kfree_rcu(nc_path, rcu); |
236 | } |
237 | |
238 | /** |
239 | * batadv_nc_path_put() - decrement the nc_path refcounter and possibly |
240 | * release it |
241 | * @nc_path: nc_path to be free'd |
242 | */ |
243 | static void batadv_nc_path_put(struct batadv_nc_path *nc_path) |
244 | { |
245 | if (!nc_path) |
246 | return; |
247 | |
248 | kref_put(kref: &nc_path->refcount, release: batadv_nc_path_release); |
249 | } |
250 | |
251 | /** |
252 | * batadv_nc_packet_free() - frees nc packet |
253 | * @nc_packet: the nc packet to free |
254 | * @dropped: whether the packet is freed because is dropped |
255 | */ |
256 | static void batadv_nc_packet_free(struct batadv_nc_packet *nc_packet, |
257 | bool dropped) |
258 | { |
259 | if (dropped) |
260 | kfree_skb(skb: nc_packet->skb); |
261 | else |
262 | consume_skb(skb: nc_packet->skb); |
263 | |
264 | batadv_nc_path_put(nc_path: nc_packet->nc_path); |
265 | kfree(objp: nc_packet); |
266 | } |
267 | |
268 | /** |
269 | * batadv_nc_to_purge_nc_node() - checks whether an nc node has to be purged |
270 | * @bat_priv: the bat priv with all the soft interface information |
271 | * @nc_node: the nc node to check |
272 | * |
273 | * Return: true if the entry has to be purged now, false otherwise |
274 | */ |
275 | static bool batadv_nc_to_purge_nc_node(struct batadv_priv *bat_priv, |
276 | struct batadv_nc_node *nc_node) |
277 | { |
278 | if (atomic_read(v: &bat_priv->mesh_state) != BATADV_MESH_ACTIVE) |
279 | return true; |
280 | |
281 | return batadv_has_timed_out(timestamp: nc_node->last_seen, BATADV_NC_NODE_TIMEOUT); |
282 | } |
283 | |
284 | /** |
285 | * batadv_nc_to_purge_nc_path_coding() - checks whether an nc path has timed out |
286 | * @bat_priv: the bat priv with all the soft interface information |
287 | * @nc_path: the nc path to check |
288 | * |
289 | * Return: true if the entry has to be purged now, false otherwise |
290 | */ |
291 | static bool batadv_nc_to_purge_nc_path_coding(struct batadv_priv *bat_priv, |
292 | struct batadv_nc_path *nc_path) |
293 | { |
294 | if (atomic_read(v: &bat_priv->mesh_state) != BATADV_MESH_ACTIVE) |
295 | return true; |
296 | |
297 | /* purge the path when no packets has been added for 10 times the |
298 | * max_fwd_delay time |
299 | */ |
300 | return batadv_has_timed_out(timestamp: nc_path->last_valid, |
301 | timeout: bat_priv->nc.max_fwd_delay * 10); |
302 | } |
303 | |
304 | /** |
305 | * batadv_nc_to_purge_nc_path_decoding() - checks whether an nc path has timed |
306 | * out |
307 | * @bat_priv: the bat priv with all the soft interface information |
308 | * @nc_path: the nc path to check |
309 | * |
310 | * Return: true if the entry has to be purged now, false otherwise |
311 | */ |
312 | static bool batadv_nc_to_purge_nc_path_decoding(struct batadv_priv *bat_priv, |
313 | struct batadv_nc_path *nc_path) |
314 | { |
315 | if (atomic_read(v: &bat_priv->mesh_state) != BATADV_MESH_ACTIVE) |
316 | return true; |
317 | |
318 | /* purge the path when no packets has been added for 10 times the |
319 | * max_buffer time |
320 | */ |
321 | return batadv_has_timed_out(timestamp: nc_path->last_valid, |
322 | timeout: bat_priv->nc.max_buffer_time * 10); |
323 | } |
324 | |
325 | /** |
326 | * batadv_nc_purge_orig_nc_nodes() - go through list of nc nodes and purge stale |
327 | * entries |
328 | * @bat_priv: the bat priv with all the soft interface information |
329 | * @list: list of nc nodes |
330 | * @lock: nc node list lock |
331 | * @to_purge: function in charge to decide whether an entry has to be purged or |
332 | * not. This function takes the nc node as argument and has to return |
333 | * a boolean value: true if the entry has to be deleted, false |
334 | * otherwise |
335 | */ |
336 | static void |
337 | batadv_nc_purge_orig_nc_nodes(struct batadv_priv *bat_priv, |
338 | struct list_head *list, |
339 | spinlock_t *lock, |
340 | bool (*to_purge)(struct batadv_priv *, |
341 | struct batadv_nc_node *)) |
342 | { |
343 | struct batadv_nc_node *nc_node, *nc_node_tmp; |
344 | |
345 | /* For each nc_node in list */ |
346 | spin_lock_bh(lock); |
347 | list_for_each_entry_safe(nc_node, nc_node_tmp, list, list) { |
348 | /* if an helper function has been passed as parameter, |
349 | * ask it if the entry has to be purged or not |
350 | */ |
351 | if (to_purge && !to_purge(bat_priv, nc_node)) |
352 | continue; |
353 | |
354 | batadv_dbg(BATADV_DBG_NC, bat_priv, |
355 | "Removing nc_node %pM -> %pM\n" , |
356 | nc_node->addr, nc_node->orig_node->orig); |
357 | list_del_rcu(entry: &nc_node->list); |
358 | batadv_nc_node_put(nc_node); |
359 | } |
360 | spin_unlock_bh(lock); |
361 | } |
362 | |
363 | /** |
364 | * batadv_nc_purge_orig() - purges all nc node data attached of the given |
365 | * originator |
366 | * @bat_priv: the bat priv with all the soft interface information |
367 | * @orig_node: orig_node with the nc node entries to be purged |
368 | * @to_purge: function in charge to decide whether an entry has to be purged or |
369 | * not. This function takes the nc node as argument and has to return |
370 | * a boolean value: true is the entry has to be deleted, false |
371 | * otherwise |
372 | */ |
373 | void batadv_nc_purge_orig(struct batadv_priv *bat_priv, |
374 | struct batadv_orig_node *orig_node, |
375 | bool (*to_purge)(struct batadv_priv *, |
376 | struct batadv_nc_node *)) |
377 | { |
378 | /* Check ingoing nc_node's of this orig_node */ |
379 | batadv_nc_purge_orig_nc_nodes(bat_priv, list: &orig_node->in_coding_list, |
380 | lock: &orig_node->in_coding_list_lock, |
381 | to_purge); |
382 | |
383 | /* Check outgoing nc_node's of this orig_node */ |
384 | batadv_nc_purge_orig_nc_nodes(bat_priv, list: &orig_node->out_coding_list, |
385 | lock: &orig_node->out_coding_list_lock, |
386 | to_purge); |
387 | } |
388 | |
389 | /** |
390 | * batadv_nc_purge_orig_hash() - traverse entire originator hash to check if |
391 | * they have timed out nc nodes |
392 | * @bat_priv: the bat priv with all the soft interface information |
393 | */ |
394 | static void batadv_nc_purge_orig_hash(struct batadv_priv *bat_priv) |
395 | { |
396 | struct batadv_hashtable *hash = bat_priv->orig_hash; |
397 | struct hlist_head *head; |
398 | struct batadv_orig_node *orig_node; |
399 | u32 i; |
400 | |
401 | if (!hash) |
402 | return; |
403 | |
404 | /* For each orig_node */ |
405 | for (i = 0; i < hash->size; i++) { |
406 | head = &hash->table[i]; |
407 | |
408 | rcu_read_lock(); |
409 | hlist_for_each_entry_rcu(orig_node, head, hash_entry) |
410 | batadv_nc_purge_orig(bat_priv, orig_node, |
411 | to_purge: batadv_nc_to_purge_nc_node); |
412 | rcu_read_unlock(); |
413 | } |
414 | } |
415 | |
416 | /** |
417 | * batadv_nc_purge_paths() - traverse all nc paths part of the hash and remove |
418 | * unused ones |
419 | * @bat_priv: the bat priv with all the soft interface information |
420 | * @hash: hash table containing the nc paths to check |
421 | * @to_purge: function in charge to decide whether an entry has to be purged or |
422 | * not. This function takes the nc node as argument and has to return |
423 | * a boolean value: true is the entry has to be deleted, false |
424 | * otherwise |
425 | */ |
426 | static void batadv_nc_purge_paths(struct batadv_priv *bat_priv, |
427 | struct batadv_hashtable *hash, |
428 | bool (*to_purge)(struct batadv_priv *, |
429 | struct batadv_nc_path *)) |
430 | { |
431 | struct hlist_head *head; |
432 | struct hlist_node *node_tmp; |
433 | struct batadv_nc_path *nc_path; |
434 | spinlock_t *lock; /* Protects lists in hash */ |
435 | u32 i; |
436 | |
437 | for (i = 0; i < hash->size; i++) { |
438 | head = &hash->table[i]; |
439 | lock = &hash->list_locks[i]; |
440 | |
441 | /* For each nc_path in this bin */ |
442 | spin_lock_bh(lock); |
443 | hlist_for_each_entry_safe(nc_path, node_tmp, head, hash_entry) { |
444 | /* if an helper function has been passed as parameter, |
445 | * ask it if the entry has to be purged or not |
446 | */ |
447 | if (to_purge && !to_purge(bat_priv, nc_path)) |
448 | continue; |
449 | |
450 | /* purging an non-empty nc_path should never happen, but |
451 | * is observed under high CPU load. Delay the purging |
452 | * until next iteration to allow the packet_list to be |
453 | * emptied first. |
454 | */ |
455 | if (!unlikely(list_empty(&nc_path->packet_list))) { |
456 | net_ratelimited_function(printk, |
457 | KERN_WARNING |
458 | "Skipping free of non-empty nc_path (%pM -> %pM)!\n" , |
459 | nc_path->prev_hop, |
460 | nc_path->next_hop); |
461 | continue; |
462 | } |
463 | |
464 | /* nc_path is unused, so remove it */ |
465 | batadv_dbg(BATADV_DBG_NC, bat_priv, |
466 | "Remove nc_path %pM -> %pM\n" , |
467 | nc_path->prev_hop, nc_path->next_hop); |
468 | hlist_del_rcu(n: &nc_path->hash_entry); |
469 | batadv_nc_path_put(nc_path); |
470 | } |
471 | spin_unlock_bh(lock); |
472 | } |
473 | } |
474 | |
475 | /** |
476 | * batadv_nc_hash_key_gen() - computes the nc_path hash key |
477 | * @key: buffer to hold the final hash key |
478 | * @src: source ethernet mac address going into the hash key |
479 | * @dst: destination ethernet mac address going into the hash key |
480 | */ |
481 | static void batadv_nc_hash_key_gen(struct batadv_nc_path *key, const char *src, |
482 | const char *dst) |
483 | { |
484 | memcpy(key->prev_hop, src, sizeof(key->prev_hop)); |
485 | memcpy(key->next_hop, dst, sizeof(key->next_hop)); |
486 | } |
487 | |
488 | /** |
489 | * batadv_nc_hash_choose() - compute the hash value for an nc path |
490 | * @data: data to hash |
491 | * @size: size of the hash table |
492 | * |
493 | * Return: the selected index in the hash table for the given data. |
494 | */ |
495 | static u32 batadv_nc_hash_choose(const void *data, u32 size) |
496 | { |
497 | const struct batadv_nc_path *nc_path = data; |
498 | u32 hash = 0; |
499 | |
500 | hash = jhash(key: &nc_path->prev_hop, length: sizeof(nc_path->prev_hop), initval: hash); |
501 | hash = jhash(key: &nc_path->next_hop, length: sizeof(nc_path->next_hop), initval: hash); |
502 | |
503 | return hash % size; |
504 | } |
505 | |
506 | /** |
507 | * batadv_nc_hash_compare() - comparing function used in the network coding hash |
508 | * tables |
509 | * @node: node in the local table |
510 | * @data2: second object to compare the node to |
511 | * |
512 | * Return: true if the two entry are the same, false otherwise |
513 | */ |
514 | static bool batadv_nc_hash_compare(const struct hlist_node *node, |
515 | const void *data2) |
516 | { |
517 | const struct batadv_nc_path *nc_path1, *nc_path2; |
518 | |
519 | nc_path1 = container_of(node, struct batadv_nc_path, hash_entry); |
520 | nc_path2 = data2; |
521 | |
522 | /* Return 1 if the two keys are identical */ |
523 | if (!batadv_compare_eth(data1: nc_path1->prev_hop, data2: nc_path2->prev_hop)) |
524 | return false; |
525 | |
526 | if (!batadv_compare_eth(data1: nc_path1->next_hop, data2: nc_path2->next_hop)) |
527 | return false; |
528 | |
529 | return true; |
530 | } |
531 | |
532 | /** |
533 | * batadv_nc_hash_find() - search for an existing nc path and return it |
534 | * @hash: hash table containing the nc path |
535 | * @data: search key |
536 | * |
537 | * Return: the nc_path if found, NULL otherwise. |
538 | */ |
539 | static struct batadv_nc_path * |
540 | batadv_nc_hash_find(struct batadv_hashtable *hash, |
541 | void *data) |
542 | { |
543 | struct hlist_head *head; |
544 | struct batadv_nc_path *nc_path, *nc_path_tmp = NULL; |
545 | int index; |
546 | |
547 | if (!hash) |
548 | return NULL; |
549 | |
550 | index = batadv_nc_hash_choose(data, size: hash->size); |
551 | head = &hash->table[index]; |
552 | |
553 | rcu_read_lock(); |
554 | hlist_for_each_entry_rcu(nc_path, head, hash_entry) { |
555 | if (!batadv_nc_hash_compare(node: &nc_path->hash_entry, data2: data)) |
556 | continue; |
557 | |
558 | if (!kref_get_unless_zero(kref: &nc_path->refcount)) |
559 | continue; |
560 | |
561 | nc_path_tmp = nc_path; |
562 | break; |
563 | } |
564 | rcu_read_unlock(); |
565 | |
566 | return nc_path_tmp; |
567 | } |
568 | |
569 | /** |
570 | * batadv_nc_send_packet() - send non-coded packet and free nc_packet struct |
571 | * @nc_packet: the nc packet to send |
572 | */ |
573 | static void batadv_nc_send_packet(struct batadv_nc_packet *nc_packet) |
574 | { |
575 | batadv_send_unicast_skb(skb: nc_packet->skb, neigh_node: nc_packet->neigh_node); |
576 | nc_packet->skb = NULL; |
577 | batadv_nc_packet_free(nc_packet, dropped: false); |
578 | } |
579 | |
580 | /** |
581 | * batadv_nc_sniffed_purge() - Checks timestamp of given sniffed nc_packet. |
582 | * @bat_priv: the bat priv with all the soft interface information |
583 | * @nc_path: the nc path the packet belongs to |
584 | * @nc_packet: the nc packet to be checked |
585 | * |
586 | * Checks whether the given sniffed (overheard) nc_packet has hit its buffering |
587 | * timeout. If so, the packet is no longer kept and the entry deleted from the |
588 | * queue. Has to be called with the appropriate locks. |
589 | * |
590 | * Return: false as soon as the entry in the fifo queue has not been timed out |
591 | * yet and true otherwise. |
592 | */ |
593 | static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv, |
594 | struct batadv_nc_path *nc_path, |
595 | struct batadv_nc_packet *nc_packet) |
596 | { |
597 | unsigned long timeout = bat_priv->nc.max_buffer_time; |
598 | bool res = false; |
599 | |
600 | lockdep_assert_held(&nc_path->packet_list_lock); |
601 | |
602 | /* Packets are added to tail, so the remaining packets did not time |
603 | * out and we can stop processing the current queue |
604 | */ |
605 | if (atomic_read(v: &bat_priv->mesh_state) == BATADV_MESH_ACTIVE && |
606 | !batadv_has_timed_out(timestamp: nc_packet->timestamp, timeout)) |
607 | goto out; |
608 | |
609 | /* purge nc packet */ |
610 | list_del(entry: &nc_packet->list); |
611 | batadv_nc_packet_free(nc_packet, dropped: true); |
612 | |
613 | res = true; |
614 | |
615 | out: |
616 | return res; |
617 | } |
618 | |
619 | /** |
620 | * batadv_nc_fwd_flush() - Checks the timestamp of the given nc packet. |
621 | * @bat_priv: the bat priv with all the soft interface information |
622 | * @nc_path: the nc path the packet belongs to |
623 | * @nc_packet: the nc packet to be checked |
624 | * |
625 | * Checks whether the given nc packet has hit its forward timeout. If so, the |
626 | * packet is no longer delayed, immediately sent and the entry deleted from the |
627 | * queue. Has to be called with the appropriate locks. |
628 | * |
629 | * Return: false as soon as the entry in the fifo queue has not been timed out |
630 | * yet and true otherwise. |
631 | */ |
632 | static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv, |
633 | struct batadv_nc_path *nc_path, |
634 | struct batadv_nc_packet *nc_packet) |
635 | { |
636 | unsigned long timeout = bat_priv->nc.max_fwd_delay; |
637 | |
638 | lockdep_assert_held(&nc_path->packet_list_lock); |
639 | |
640 | /* Packets are added to tail, so the remaining packets did not time |
641 | * out and we can stop processing the current queue |
642 | */ |
643 | if (atomic_read(v: &bat_priv->mesh_state) == BATADV_MESH_ACTIVE && |
644 | !batadv_has_timed_out(timestamp: nc_packet->timestamp, timeout)) |
645 | return false; |
646 | |
647 | /* Send packet */ |
648 | batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD); |
649 | batadv_add_counter(bat_priv, idx: BATADV_CNT_FORWARD_BYTES, |
650 | count: nc_packet->skb->len + ETH_HLEN); |
651 | list_del(entry: &nc_packet->list); |
652 | batadv_nc_send_packet(nc_packet); |
653 | |
654 | return true; |
655 | } |
656 | |
657 | /** |
658 | * batadv_nc_process_nc_paths() - traverse given nc packet pool and free timed |
659 | * out nc packets |
660 | * @bat_priv: the bat priv with all the soft interface information |
661 | * @hash: to be processed hash table |
662 | * @process_fn: Function called to process given nc packet. Should return true |
663 | * to encourage this function to proceed with the next packet. |
664 | * Otherwise the rest of the current queue is skipped. |
665 | */ |
666 | static void |
667 | batadv_nc_process_nc_paths(struct batadv_priv *bat_priv, |
668 | struct batadv_hashtable *hash, |
669 | bool (*process_fn)(struct batadv_priv *, |
670 | struct batadv_nc_path *, |
671 | struct batadv_nc_packet *)) |
672 | { |
673 | struct hlist_head *head; |
674 | struct batadv_nc_packet *nc_packet, *nc_packet_tmp; |
675 | struct batadv_nc_path *nc_path; |
676 | bool ret; |
677 | int i; |
678 | |
679 | if (!hash) |
680 | return; |
681 | |
682 | /* Loop hash table bins */ |
683 | for (i = 0; i < hash->size; i++) { |
684 | head = &hash->table[i]; |
685 | |
686 | /* Loop coding paths */ |
687 | rcu_read_lock(); |
688 | hlist_for_each_entry_rcu(nc_path, head, hash_entry) { |
689 | /* Loop packets */ |
690 | spin_lock_bh(lock: &nc_path->packet_list_lock); |
691 | list_for_each_entry_safe(nc_packet, nc_packet_tmp, |
692 | &nc_path->packet_list, list) { |
693 | ret = process_fn(bat_priv, nc_path, nc_packet); |
694 | if (!ret) |
695 | break; |
696 | } |
697 | spin_unlock_bh(lock: &nc_path->packet_list_lock); |
698 | } |
699 | rcu_read_unlock(); |
700 | } |
701 | } |
702 | |
703 | /** |
704 | * batadv_nc_worker() - periodic task for housekeeping related to network |
705 | * coding |
706 | * @work: kernel work struct |
707 | */ |
708 | static void batadv_nc_worker(struct work_struct *work) |
709 | { |
710 | struct delayed_work *delayed_work; |
711 | struct batadv_priv_nc *priv_nc; |
712 | struct batadv_priv *bat_priv; |
713 | unsigned long timeout; |
714 | |
715 | delayed_work = to_delayed_work(work); |
716 | priv_nc = container_of(delayed_work, struct batadv_priv_nc, work); |
717 | bat_priv = container_of(priv_nc, struct batadv_priv, nc); |
718 | |
719 | batadv_nc_purge_orig_hash(bat_priv); |
720 | batadv_nc_purge_paths(bat_priv, hash: bat_priv->nc.coding_hash, |
721 | to_purge: batadv_nc_to_purge_nc_path_coding); |
722 | batadv_nc_purge_paths(bat_priv, hash: bat_priv->nc.decoding_hash, |
723 | to_purge: batadv_nc_to_purge_nc_path_decoding); |
724 | |
725 | timeout = bat_priv->nc.max_fwd_delay; |
726 | |
727 | if (batadv_has_timed_out(timestamp: bat_priv->nc.timestamp_fwd_flush, timeout)) { |
728 | batadv_nc_process_nc_paths(bat_priv, hash: bat_priv->nc.coding_hash, |
729 | process_fn: batadv_nc_fwd_flush); |
730 | bat_priv->nc.timestamp_fwd_flush = jiffies; |
731 | } |
732 | |
733 | if (batadv_has_timed_out(timestamp: bat_priv->nc.timestamp_sniffed_purge, |
734 | timeout: bat_priv->nc.max_buffer_time)) { |
735 | batadv_nc_process_nc_paths(bat_priv, hash: bat_priv->nc.decoding_hash, |
736 | process_fn: batadv_nc_sniffed_purge); |
737 | bat_priv->nc.timestamp_sniffed_purge = jiffies; |
738 | } |
739 | |
740 | /* Schedule a new check */ |
741 | batadv_nc_start_timer(bat_priv); |
742 | } |
743 | |
744 | /** |
745 | * batadv_can_nc_with_orig() - checks whether the given orig node is suitable |
746 | * for coding or not |
747 | * @bat_priv: the bat priv with all the soft interface information |
748 | * @orig_node: neighboring orig node which may be used as nc candidate |
749 | * @ogm_packet: incoming ogm packet also used for the checks |
750 | * |
751 | * Return: true if: |
752 | * 1) The OGM must have the most recent sequence number. |
753 | * 2) The TTL must be decremented by one and only one. |
754 | * 3) The OGM must be received from the first hop from orig_node. |
755 | * 4) The TQ value of the OGM must be above bat_priv->nc.min_tq. |
756 | */ |
757 | static bool batadv_can_nc_with_orig(struct batadv_priv *bat_priv, |
758 | struct batadv_orig_node *orig_node, |
759 | struct batadv_ogm_packet *ogm_packet) |
760 | { |
761 | struct batadv_orig_ifinfo *orig_ifinfo; |
762 | u32 last_real_seqno; |
763 | u8 last_ttl; |
764 | |
765 | orig_ifinfo = batadv_orig_ifinfo_get(orig_node, BATADV_IF_DEFAULT); |
766 | if (!orig_ifinfo) |
767 | return false; |
768 | |
769 | last_ttl = orig_ifinfo->last_ttl; |
770 | last_real_seqno = orig_ifinfo->last_real_seqno; |
771 | batadv_orig_ifinfo_put(orig_ifinfo); |
772 | |
773 | if (last_real_seqno != ntohl(ogm_packet->seqno)) |
774 | return false; |
775 | if (last_ttl != ogm_packet->ttl + 1) |
776 | return false; |
777 | if (!batadv_compare_eth(data1: ogm_packet->orig, data2: ogm_packet->prev_sender)) |
778 | return false; |
779 | if (ogm_packet->tq < bat_priv->nc.min_tq) |
780 | return false; |
781 | |
782 | return true; |
783 | } |
784 | |
785 | /** |
786 | * batadv_nc_find_nc_node() - search for an existing nc node and return it |
787 | * @orig_node: orig node originating the ogm packet |
788 | * @orig_neigh_node: neighboring orig node from which we received the ogm packet |
789 | * (can be equal to orig_node) |
790 | * @in_coding: traverse incoming or outgoing network coding list |
791 | * |
792 | * Return: the nc_node if found, NULL otherwise. |
793 | */ |
794 | static struct batadv_nc_node * |
795 | batadv_nc_find_nc_node(struct batadv_orig_node *orig_node, |
796 | struct batadv_orig_node *orig_neigh_node, |
797 | bool in_coding) |
798 | { |
799 | struct batadv_nc_node *nc_node, *nc_node_out = NULL; |
800 | struct list_head *list; |
801 | |
802 | if (in_coding) |
803 | list = &orig_neigh_node->in_coding_list; |
804 | else |
805 | list = &orig_neigh_node->out_coding_list; |
806 | |
807 | /* Traverse list of nc_nodes to orig_node */ |
808 | rcu_read_lock(); |
809 | list_for_each_entry_rcu(nc_node, list, list) { |
810 | if (!batadv_compare_eth(data1: nc_node->addr, data2: orig_node->orig)) |
811 | continue; |
812 | |
813 | if (!kref_get_unless_zero(kref: &nc_node->refcount)) |
814 | continue; |
815 | |
816 | /* Found a match */ |
817 | nc_node_out = nc_node; |
818 | break; |
819 | } |
820 | rcu_read_unlock(); |
821 | |
822 | return nc_node_out; |
823 | } |
824 | |
825 | /** |
826 | * batadv_nc_get_nc_node() - retrieves an nc node or creates the entry if it was |
827 | * not found |
828 | * @bat_priv: the bat priv with all the soft interface information |
829 | * @orig_node: orig node originating the ogm packet |
830 | * @orig_neigh_node: neighboring orig node from which we received the ogm packet |
831 | * (can be equal to orig_node) |
832 | * @in_coding: traverse incoming or outgoing network coding list |
833 | * |
834 | * Return: the nc_node if found or created, NULL in case of an error. |
835 | */ |
836 | static struct batadv_nc_node * |
837 | batadv_nc_get_nc_node(struct batadv_priv *bat_priv, |
838 | struct batadv_orig_node *orig_node, |
839 | struct batadv_orig_node *orig_neigh_node, |
840 | bool in_coding) |
841 | { |
842 | struct batadv_nc_node *nc_node; |
843 | spinlock_t *lock; /* Used to lock list selected by "int in_coding" */ |
844 | struct list_head *list; |
845 | |
846 | /* Select ingoing or outgoing coding node */ |
847 | if (in_coding) { |
848 | lock = &orig_neigh_node->in_coding_list_lock; |
849 | list = &orig_neigh_node->in_coding_list; |
850 | } else { |
851 | lock = &orig_neigh_node->out_coding_list_lock; |
852 | list = &orig_neigh_node->out_coding_list; |
853 | } |
854 | |
855 | spin_lock_bh(lock); |
856 | |
857 | /* Check if nc_node is already added */ |
858 | nc_node = batadv_nc_find_nc_node(orig_node, orig_neigh_node, in_coding); |
859 | |
860 | /* Node found */ |
861 | if (nc_node) |
862 | goto unlock; |
863 | |
864 | nc_node = kzalloc(size: sizeof(*nc_node), GFP_ATOMIC); |
865 | if (!nc_node) |
866 | goto unlock; |
867 | |
868 | /* Initialize nc_node */ |
869 | INIT_LIST_HEAD(list: &nc_node->list); |
870 | kref_init(kref: &nc_node->refcount); |
871 | ether_addr_copy(dst: nc_node->addr, src: orig_node->orig); |
872 | kref_get(kref: &orig_neigh_node->refcount); |
873 | nc_node->orig_node = orig_neigh_node; |
874 | |
875 | batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_node %pM -> %pM\n" , |
876 | nc_node->addr, nc_node->orig_node->orig); |
877 | |
878 | /* Add nc_node to orig_node */ |
879 | kref_get(kref: &nc_node->refcount); |
880 | list_add_tail_rcu(new: &nc_node->list, head: list); |
881 | |
882 | unlock: |
883 | spin_unlock_bh(lock); |
884 | |
885 | return nc_node; |
886 | } |
887 | |
888 | /** |
889 | * batadv_nc_update_nc_node() - updates stored incoming and outgoing nc node |
890 | * structs (best called on incoming OGMs) |
891 | * @bat_priv: the bat priv with all the soft interface information |
892 | * @orig_node: orig node originating the ogm packet |
893 | * @orig_neigh_node: neighboring orig node from which we received the ogm packet |
894 | * (can be equal to orig_node) |
895 | * @ogm_packet: incoming ogm packet |
896 | * @is_single_hop_neigh: orig_node is a single hop neighbor |
897 | */ |
898 | void batadv_nc_update_nc_node(struct batadv_priv *bat_priv, |
899 | struct batadv_orig_node *orig_node, |
900 | struct batadv_orig_node *orig_neigh_node, |
901 | struct batadv_ogm_packet *ogm_packet, |
902 | int is_single_hop_neigh) |
903 | { |
904 | struct batadv_nc_node *in_nc_node = NULL; |
905 | struct batadv_nc_node *out_nc_node = NULL; |
906 | |
907 | /* Check if network coding is enabled */ |
908 | if (!atomic_read(v: &bat_priv->network_coding)) |
909 | goto out; |
910 | |
911 | /* check if orig node is network coding enabled */ |
912 | if (!test_bit(BATADV_ORIG_CAPA_HAS_NC, &orig_node->capabilities)) |
913 | goto out; |
914 | |
915 | /* accept ogms from 'good' neighbors and single hop neighbors */ |
916 | if (!batadv_can_nc_with_orig(bat_priv, orig_node, ogm_packet) && |
917 | !is_single_hop_neigh) |
918 | goto out; |
919 | |
920 | /* Add orig_node as in_nc_node on hop */ |
921 | in_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node, |
922 | orig_neigh_node, in_coding: true); |
923 | if (!in_nc_node) |
924 | goto out; |
925 | |
926 | in_nc_node->last_seen = jiffies; |
927 | |
928 | /* Add hop as out_nc_node on orig_node */ |
929 | out_nc_node = batadv_nc_get_nc_node(bat_priv, orig_node: orig_neigh_node, |
930 | orig_neigh_node: orig_node, in_coding: false); |
931 | if (!out_nc_node) |
932 | goto out; |
933 | |
934 | out_nc_node->last_seen = jiffies; |
935 | |
936 | out: |
937 | batadv_nc_node_put(nc_node: in_nc_node); |
938 | batadv_nc_node_put(nc_node: out_nc_node); |
939 | } |
940 | |
941 | /** |
942 | * batadv_nc_get_path() - get existing nc_path or allocate a new one |
943 | * @bat_priv: the bat priv with all the soft interface information |
944 | * @hash: hash table containing the nc path |
945 | * @src: ethernet source address - first half of the nc path search key |
946 | * @dst: ethernet destination address - second half of the nc path search key |
947 | * |
948 | * Return: pointer to nc_path if the path was found or created, returns NULL |
949 | * on error. |
950 | */ |
951 | static struct batadv_nc_path *batadv_nc_get_path(struct batadv_priv *bat_priv, |
952 | struct batadv_hashtable *hash, |
953 | u8 *src, |
954 | u8 *dst) |
955 | { |
956 | int hash_added; |
957 | struct batadv_nc_path *nc_path, nc_path_key; |
958 | |
959 | batadv_nc_hash_key_gen(key: &nc_path_key, src, dst); |
960 | |
961 | /* Search for existing nc_path */ |
962 | nc_path = batadv_nc_hash_find(hash, data: (void *)&nc_path_key); |
963 | |
964 | if (nc_path) { |
965 | /* Set timestamp to delay removal of nc_path */ |
966 | nc_path->last_valid = jiffies; |
967 | return nc_path; |
968 | } |
969 | |
970 | /* No existing nc_path was found; create a new */ |
971 | nc_path = kzalloc(size: sizeof(*nc_path), GFP_ATOMIC); |
972 | |
973 | if (!nc_path) |
974 | return NULL; |
975 | |
976 | /* Initialize nc_path */ |
977 | INIT_LIST_HEAD(list: &nc_path->packet_list); |
978 | spin_lock_init(&nc_path->packet_list_lock); |
979 | kref_init(kref: &nc_path->refcount); |
980 | nc_path->last_valid = jiffies; |
981 | ether_addr_copy(dst: nc_path->next_hop, src: dst); |
982 | ether_addr_copy(dst: nc_path->prev_hop, src); |
983 | |
984 | batadv_dbg(BATADV_DBG_NC, bat_priv, "Adding nc_path %pM -> %pM\n" , |
985 | nc_path->prev_hop, |
986 | nc_path->next_hop); |
987 | |
988 | /* Add nc_path to hash table */ |
989 | kref_get(kref: &nc_path->refcount); |
990 | hash_added = batadv_hash_add(hash, compare: batadv_nc_hash_compare, |
991 | choose: batadv_nc_hash_choose, data: &nc_path_key, |
992 | data_node: &nc_path->hash_entry); |
993 | |
994 | if (hash_added < 0) { |
995 | kfree(objp: nc_path); |
996 | return NULL; |
997 | } |
998 | |
999 | return nc_path; |
1000 | } |
1001 | |
1002 | /** |
1003 | * batadv_nc_random_weight_tq() - scale the receivers TQ-value to avoid unfair |
1004 | * selection of a receiver with slightly lower TQ than the other |
1005 | * @tq: to be weighted tq value |
1006 | * |
1007 | * Return: scaled tq value |
1008 | */ |
1009 | static u8 batadv_nc_random_weight_tq(u8 tq) |
1010 | { |
1011 | /* randomize the estimated packet loss (max TQ - estimated TQ) */ |
1012 | u8 rand_tq = get_random_u32_below(BATADV_TQ_MAX_VALUE + 1 - tq); |
1013 | |
1014 | /* convert to (randomized) estimated tq again */ |
1015 | return BATADV_TQ_MAX_VALUE - rand_tq; |
1016 | } |
1017 | |
1018 | /** |
1019 | * batadv_nc_memxor() - XOR destination with source |
1020 | * @dst: byte array to XOR into |
1021 | * @src: byte array to XOR from |
1022 | * @len: length of destination array |
1023 | */ |
1024 | static void batadv_nc_memxor(char *dst, const char *src, unsigned int len) |
1025 | { |
1026 | unsigned int i; |
1027 | |
1028 | for (i = 0; i < len; ++i) |
1029 | dst[i] ^= src[i]; |
1030 | } |
1031 | |
1032 | /** |
1033 | * batadv_nc_code_packets() - code a received unicast_packet with an nc packet |
1034 | * into a coded_packet and send it |
1035 | * @bat_priv: the bat priv with all the soft interface information |
1036 | * @skb: data skb to forward |
1037 | * @ethhdr: pointer to the ethernet header inside the skb |
1038 | * @nc_packet: structure containing the packet to the skb can be coded with |
1039 | * @neigh_node: next hop to forward packet to |
1040 | * |
1041 | * Return: true if both packets are consumed, false otherwise. |
1042 | */ |
1043 | static bool batadv_nc_code_packets(struct batadv_priv *bat_priv, |
1044 | struct sk_buff *skb, |
1045 | struct ethhdr *ethhdr, |
1046 | struct batadv_nc_packet *nc_packet, |
1047 | struct batadv_neigh_node *neigh_node) |
1048 | { |
1049 | u8 tq_weighted_neigh, tq_weighted_coding, tq_tmp; |
1050 | struct sk_buff *skb_dest, *skb_src; |
1051 | struct batadv_unicast_packet *packet1; |
1052 | struct batadv_unicast_packet *packet2; |
1053 | struct batadv_coded_packet *coded_packet; |
1054 | struct batadv_neigh_node *neigh_tmp, *router_neigh, *first_dest; |
1055 | struct batadv_neigh_node *router_coding = NULL, *second_dest; |
1056 | struct batadv_neigh_ifinfo *router_neigh_ifinfo = NULL; |
1057 | struct batadv_neigh_ifinfo *router_coding_ifinfo = NULL; |
1058 | u8 *first_source, *second_source; |
1059 | __be32 packet_id1, packet_id2; |
1060 | size_t count; |
1061 | bool res = false; |
1062 | int coding_len; |
1063 | int unicast_size = sizeof(*packet1); |
1064 | int coded_size = sizeof(*coded_packet); |
1065 | int = coded_size - unicast_size; |
1066 | |
1067 | /* TODO: do we need to consider the outgoing interface for |
1068 | * coded packets? |
1069 | */ |
1070 | router_neigh = batadv_orig_router_get(orig_node: neigh_node->orig_node, |
1071 | BATADV_IF_DEFAULT); |
1072 | if (!router_neigh) |
1073 | goto out; |
1074 | |
1075 | router_neigh_ifinfo = batadv_neigh_ifinfo_get(neigh: router_neigh, |
1076 | BATADV_IF_DEFAULT); |
1077 | if (!router_neigh_ifinfo) |
1078 | goto out; |
1079 | |
1080 | neigh_tmp = nc_packet->neigh_node; |
1081 | router_coding = batadv_orig_router_get(orig_node: neigh_tmp->orig_node, |
1082 | BATADV_IF_DEFAULT); |
1083 | if (!router_coding) |
1084 | goto out; |
1085 | |
1086 | router_coding_ifinfo = batadv_neigh_ifinfo_get(neigh: router_coding, |
1087 | BATADV_IF_DEFAULT); |
1088 | if (!router_coding_ifinfo) |
1089 | goto out; |
1090 | |
1091 | tq_tmp = router_neigh_ifinfo->bat_iv.tq_avg; |
1092 | tq_weighted_neigh = batadv_nc_random_weight_tq(tq: tq_tmp); |
1093 | tq_tmp = router_coding_ifinfo->bat_iv.tq_avg; |
1094 | tq_weighted_coding = batadv_nc_random_weight_tq(tq: tq_tmp); |
1095 | |
1096 | /* Select one destination for the MAC-header dst-field based on |
1097 | * weighted TQ-values. |
1098 | */ |
1099 | if (tq_weighted_neigh >= tq_weighted_coding) { |
1100 | /* Destination from nc_packet is selected for MAC-header */ |
1101 | first_dest = nc_packet->neigh_node; |
1102 | first_source = nc_packet->nc_path->prev_hop; |
1103 | second_dest = neigh_node; |
1104 | second_source = ethhdr->h_source; |
1105 | packet1 = (struct batadv_unicast_packet *)nc_packet->skb->data; |
1106 | packet2 = (struct batadv_unicast_packet *)skb->data; |
1107 | packet_id1 = nc_packet->packet_id; |
1108 | packet_id2 = batadv_skb_crc32(skb, |
1109 | payload_ptr: skb->data + sizeof(*packet2)); |
1110 | } else { |
1111 | /* Destination for skb is selected for MAC-header */ |
1112 | first_dest = neigh_node; |
1113 | first_source = ethhdr->h_source; |
1114 | second_dest = nc_packet->neigh_node; |
1115 | second_source = nc_packet->nc_path->prev_hop; |
1116 | packet1 = (struct batadv_unicast_packet *)skb->data; |
1117 | packet2 = (struct batadv_unicast_packet *)nc_packet->skb->data; |
1118 | packet_id1 = batadv_skb_crc32(skb, |
1119 | payload_ptr: skb->data + sizeof(*packet1)); |
1120 | packet_id2 = nc_packet->packet_id; |
1121 | } |
1122 | |
1123 | /* Instead of zero padding the smallest data buffer, we |
1124 | * code into the largest. |
1125 | */ |
1126 | if (skb->len <= nc_packet->skb->len) { |
1127 | skb_dest = nc_packet->skb; |
1128 | skb_src = skb; |
1129 | } else { |
1130 | skb_dest = skb; |
1131 | skb_src = nc_packet->skb; |
1132 | } |
1133 | |
1134 | /* coding_len is used when decoding the packet shorter packet */ |
1135 | coding_len = skb_src->len - unicast_size; |
1136 | |
1137 | if (skb_linearize(skb: skb_dest) < 0 || skb_linearize(skb: skb_src) < 0) |
1138 | goto out; |
1139 | |
1140 | skb_push(skb: skb_dest, len: header_add); |
1141 | |
1142 | coded_packet = (struct batadv_coded_packet *)skb_dest->data; |
1143 | skb_reset_mac_header(skb: skb_dest); |
1144 | |
1145 | coded_packet->packet_type = BATADV_CODED; |
1146 | coded_packet->version = BATADV_COMPAT_VERSION; |
1147 | coded_packet->ttl = packet1->ttl; |
1148 | |
1149 | /* Info about first unicast packet */ |
1150 | ether_addr_copy(dst: coded_packet->first_source, src: first_source); |
1151 | ether_addr_copy(dst: coded_packet->first_orig_dest, src: packet1->dest); |
1152 | coded_packet->first_crc = packet_id1; |
1153 | coded_packet->first_ttvn = packet1->ttvn; |
1154 | |
1155 | /* Info about second unicast packet */ |
1156 | ether_addr_copy(dst: coded_packet->second_dest, src: second_dest->addr); |
1157 | ether_addr_copy(dst: coded_packet->second_source, src: second_source); |
1158 | ether_addr_copy(dst: coded_packet->second_orig_dest, src: packet2->dest); |
1159 | coded_packet->second_crc = packet_id2; |
1160 | coded_packet->second_ttl = packet2->ttl; |
1161 | coded_packet->second_ttvn = packet2->ttvn; |
1162 | coded_packet->coded_len = htons(coding_len); |
1163 | |
1164 | /* This is where the magic happens: Code skb_src into skb_dest */ |
1165 | batadv_nc_memxor(dst: skb_dest->data + coded_size, |
1166 | src: skb_src->data + unicast_size, len: coding_len); |
1167 | |
1168 | /* Update counters accordingly */ |
1169 | if (BATADV_SKB_CB(skb_src)->decoded && |
1170 | BATADV_SKB_CB(skb_dest)->decoded) { |
1171 | /* Both packets are recoded */ |
1172 | count = skb_src->len + ETH_HLEN; |
1173 | count += skb_dest->len + ETH_HLEN; |
1174 | batadv_add_counter(bat_priv, idx: BATADV_CNT_NC_RECODE, count: 2); |
1175 | batadv_add_counter(bat_priv, idx: BATADV_CNT_NC_RECODE_BYTES, count); |
1176 | } else if (!BATADV_SKB_CB(skb_src)->decoded && |
1177 | !BATADV_SKB_CB(skb_dest)->decoded) { |
1178 | /* Both packets are newly coded */ |
1179 | count = skb_src->len + ETH_HLEN; |
1180 | count += skb_dest->len + ETH_HLEN; |
1181 | batadv_add_counter(bat_priv, idx: BATADV_CNT_NC_CODE, count: 2); |
1182 | batadv_add_counter(bat_priv, idx: BATADV_CNT_NC_CODE_BYTES, count); |
1183 | } else if (BATADV_SKB_CB(skb_src)->decoded && |
1184 | !BATADV_SKB_CB(skb_dest)->decoded) { |
1185 | /* skb_src recoded and skb_dest is newly coded */ |
1186 | batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE); |
1187 | batadv_add_counter(bat_priv, idx: BATADV_CNT_NC_RECODE_BYTES, |
1188 | count: skb_src->len + ETH_HLEN); |
1189 | batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE); |
1190 | batadv_add_counter(bat_priv, idx: BATADV_CNT_NC_CODE_BYTES, |
1191 | count: skb_dest->len + ETH_HLEN); |
1192 | } else if (!BATADV_SKB_CB(skb_src)->decoded && |
1193 | BATADV_SKB_CB(skb_dest)->decoded) { |
1194 | /* skb_src is newly coded and skb_dest is recoded */ |
1195 | batadv_inc_counter(bat_priv, BATADV_CNT_NC_CODE); |
1196 | batadv_add_counter(bat_priv, idx: BATADV_CNT_NC_CODE_BYTES, |
1197 | count: skb_src->len + ETH_HLEN); |
1198 | batadv_inc_counter(bat_priv, BATADV_CNT_NC_RECODE); |
1199 | batadv_add_counter(bat_priv, idx: BATADV_CNT_NC_RECODE_BYTES, |
1200 | count: skb_dest->len + ETH_HLEN); |
1201 | } |
1202 | |
1203 | /* skb_src is now coded into skb_dest, so free it */ |
1204 | consume_skb(skb: skb_src); |
1205 | |
1206 | /* avoid duplicate free of skb from nc_packet */ |
1207 | nc_packet->skb = NULL; |
1208 | batadv_nc_packet_free(nc_packet, dropped: false); |
1209 | |
1210 | /* Send the coded packet and return true */ |
1211 | batadv_send_unicast_skb(skb: skb_dest, neigh_node: first_dest); |
1212 | res = true; |
1213 | out: |
1214 | batadv_neigh_node_put(neigh_node: router_neigh); |
1215 | batadv_neigh_node_put(neigh_node: router_coding); |
1216 | batadv_neigh_ifinfo_put(neigh_ifinfo: router_neigh_ifinfo); |
1217 | batadv_neigh_ifinfo_put(neigh_ifinfo: router_coding_ifinfo); |
1218 | return res; |
1219 | } |
1220 | |
1221 | /** |
1222 | * batadv_nc_skb_coding_possible() - true if a decoded skb is available at dst. |
1223 | * @skb: data skb to forward |
1224 | * @dst: destination mac address of the other skb to code with |
1225 | * @src: source mac address of skb |
1226 | * |
1227 | * Whenever we network code a packet we have to check whether we received it in |
1228 | * a network coded form. If so, we may not be able to use it for coding because |
1229 | * some neighbors may also have received (overheard) the packet in the network |
1230 | * coded form without being able to decode it. It is hard to know which of the |
1231 | * neighboring nodes was able to decode the packet, therefore we can only |
1232 | * re-code the packet if the source of the previous encoded packet is involved. |
1233 | * Since the source encoded the packet we can be certain it has all necessary |
1234 | * decode information. |
1235 | * |
1236 | * Return: true if coding of a decoded packet is allowed. |
1237 | */ |
1238 | static bool batadv_nc_skb_coding_possible(struct sk_buff *skb, u8 *dst, u8 *src) |
1239 | { |
1240 | if (BATADV_SKB_CB(skb)->decoded && !batadv_compare_eth(data1: dst, data2: src)) |
1241 | return false; |
1242 | return true; |
1243 | } |
1244 | |
1245 | /** |
1246 | * batadv_nc_path_search() - Find the coding path matching in_nc_node and |
1247 | * out_nc_node to retrieve a buffered packet that can be used for coding. |
1248 | * @bat_priv: the bat priv with all the soft interface information |
1249 | * @in_nc_node: pointer to skb next hop's neighbor nc node |
1250 | * @out_nc_node: pointer to skb source's neighbor nc node |
1251 | * @skb: data skb to forward |
1252 | * @eth_dst: next hop mac address of skb |
1253 | * |
1254 | * Return: true if coding of a decoded skb is allowed. |
1255 | */ |
1256 | static struct batadv_nc_packet * |
1257 | batadv_nc_path_search(struct batadv_priv *bat_priv, |
1258 | struct batadv_nc_node *in_nc_node, |
1259 | struct batadv_nc_node *out_nc_node, |
1260 | struct sk_buff *skb, |
1261 | u8 *eth_dst) |
1262 | { |
1263 | struct batadv_nc_path *nc_path, nc_path_key; |
1264 | struct batadv_nc_packet *nc_packet_out = NULL; |
1265 | struct batadv_nc_packet *nc_packet, *nc_packet_tmp; |
1266 | struct batadv_hashtable *hash = bat_priv->nc.coding_hash; |
1267 | int idx; |
1268 | |
1269 | if (!hash) |
1270 | return NULL; |
1271 | |
1272 | /* Create almost path key */ |
1273 | batadv_nc_hash_key_gen(key: &nc_path_key, src: in_nc_node->addr, |
1274 | dst: out_nc_node->addr); |
1275 | idx = batadv_nc_hash_choose(data: &nc_path_key, size: hash->size); |
1276 | |
1277 | /* Check for coding opportunities in this nc_path */ |
1278 | rcu_read_lock(); |
1279 | hlist_for_each_entry_rcu(nc_path, &hash->table[idx], hash_entry) { |
1280 | if (!batadv_compare_eth(data1: nc_path->prev_hop, data2: in_nc_node->addr)) |
1281 | continue; |
1282 | |
1283 | if (!batadv_compare_eth(data1: nc_path->next_hop, data2: out_nc_node->addr)) |
1284 | continue; |
1285 | |
1286 | spin_lock_bh(lock: &nc_path->packet_list_lock); |
1287 | if (list_empty(head: &nc_path->packet_list)) { |
1288 | spin_unlock_bh(lock: &nc_path->packet_list_lock); |
1289 | continue; |
1290 | } |
1291 | |
1292 | list_for_each_entry_safe(nc_packet, nc_packet_tmp, |
1293 | &nc_path->packet_list, list) { |
1294 | if (!batadv_nc_skb_coding_possible(skb: nc_packet->skb, |
1295 | dst: eth_dst, |
1296 | src: in_nc_node->addr)) |
1297 | continue; |
1298 | |
1299 | /* Coding opportunity is found! */ |
1300 | list_del(entry: &nc_packet->list); |
1301 | nc_packet_out = nc_packet; |
1302 | break; |
1303 | } |
1304 | |
1305 | spin_unlock_bh(lock: &nc_path->packet_list_lock); |
1306 | break; |
1307 | } |
1308 | rcu_read_unlock(); |
1309 | |
1310 | return nc_packet_out; |
1311 | } |
1312 | |
1313 | /** |
1314 | * batadv_nc_skb_src_search() - Loops through the list of neighboring nodes of |
1315 | * the skb's sender (may be equal to the originator). |
1316 | * @bat_priv: the bat priv with all the soft interface information |
1317 | * @skb: data skb to forward |
1318 | * @eth_dst: next hop mac address of skb |
1319 | * @eth_src: source mac address of skb |
1320 | * @in_nc_node: pointer to skb next hop's neighbor nc node |
1321 | * |
1322 | * Return: an nc packet if a suitable coding packet was found, NULL otherwise. |
1323 | */ |
1324 | static struct batadv_nc_packet * |
1325 | batadv_nc_skb_src_search(struct batadv_priv *bat_priv, |
1326 | struct sk_buff *skb, |
1327 | u8 *eth_dst, |
1328 | u8 *eth_src, |
1329 | struct batadv_nc_node *in_nc_node) |
1330 | { |
1331 | struct batadv_orig_node *orig_node; |
1332 | struct batadv_nc_node *out_nc_node; |
1333 | struct batadv_nc_packet *nc_packet = NULL; |
1334 | |
1335 | orig_node = batadv_orig_hash_find(bat_priv, data: eth_src); |
1336 | if (!orig_node) |
1337 | return NULL; |
1338 | |
1339 | rcu_read_lock(); |
1340 | list_for_each_entry_rcu(out_nc_node, |
1341 | &orig_node->out_coding_list, list) { |
1342 | /* Check if the skb is decoded and if recoding is possible */ |
1343 | if (!batadv_nc_skb_coding_possible(skb, |
1344 | dst: out_nc_node->addr, src: eth_src)) |
1345 | continue; |
1346 | |
1347 | /* Search for an opportunity in this nc_path */ |
1348 | nc_packet = batadv_nc_path_search(bat_priv, in_nc_node, |
1349 | out_nc_node, skb, eth_dst); |
1350 | if (nc_packet) |
1351 | break; |
1352 | } |
1353 | rcu_read_unlock(); |
1354 | |
1355 | batadv_orig_node_put(orig_node); |
1356 | return nc_packet; |
1357 | } |
1358 | |
1359 | /** |
1360 | * batadv_nc_skb_store_before_coding() - set the ethernet src and dst of the |
1361 | * unicast skb before it is stored for use in later decoding |
1362 | * @bat_priv: the bat priv with all the soft interface information |
1363 | * @skb: data skb to store |
1364 | * @eth_dst_new: new destination mac address of skb |
1365 | */ |
1366 | static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv, |
1367 | struct sk_buff *skb, |
1368 | u8 *eth_dst_new) |
1369 | { |
1370 | struct ethhdr *ethhdr; |
1371 | |
1372 | /* Copy skb header to change the mac header */ |
1373 | skb = pskb_copy_for_clone(skb, GFP_ATOMIC); |
1374 | if (!skb) |
1375 | return; |
1376 | |
1377 | /* Set the mac header as if we actually sent the packet uncoded */ |
1378 | ethhdr = eth_hdr(skb); |
1379 | ether_addr_copy(dst: ethhdr->h_source, src: ethhdr->h_dest); |
1380 | ether_addr_copy(dst: ethhdr->h_dest, src: eth_dst_new); |
1381 | |
1382 | /* Set data pointer to MAC header to mimic packets from our tx path */ |
1383 | skb_push(skb, ETH_HLEN); |
1384 | |
1385 | /* Add the packet to the decoding packet pool */ |
1386 | batadv_nc_skb_store_for_decoding(bat_priv, skb); |
1387 | |
1388 | /* batadv_nc_skb_store_for_decoding() clones the skb, so we must free |
1389 | * our ref |
1390 | */ |
1391 | consume_skb(skb); |
1392 | } |
1393 | |
1394 | /** |
1395 | * batadv_nc_skb_dst_search() - Loops through list of neighboring nodes to dst. |
1396 | * @skb: data skb to forward |
1397 | * @neigh_node: next hop to forward packet to |
1398 | * @ethhdr: pointer to the ethernet header inside the skb |
1399 | * |
1400 | * Loops through the list of neighboring nodes the next hop has a good |
1401 | * connection to (receives OGMs with a sufficient quality). We need to find a |
1402 | * neighbor of our next hop that potentially sent a packet which our next hop |
1403 | * also received (overheard) and has stored for later decoding. |
1404 | * |
1405 | * Return: true if the skb was consumed (encoded packet sent) or false otherwise |
1406 | */ |
1407 | static bool batadv_nc_skb_dst_search(struct sk_buff *skb, |
1408 | struct batadv_neigh_node *neigh_node, |
1409 | struct ethhdr *ethhdr) |
1410 | { |
1411 | struct net_device *netdev = neigh_node->if_incoming->soft_iface; |
1412 | struct batadv_priv *bat_priv = netdev_priv(dev: netdev); |
1413 | struct batadv_orig_node *orig_node = neigh_node->orig_node; |
1414 | struct batadv_nc_node *nc_node; |
1415 | struct batadv_nc_packet *nc_packet = NULL; |
1416 | |
1417 | rcu_read_lock(); |
1418 | list_for_each_entry_rcu(nc_node, &orig_node->in_coding_list, list) { |
1419 | /* Search for coding opportunity with this in_nc_node */ |
1420 | nc_packet = batadv_nc_skb_src_search(bat_priv, skb, |
1421 | eth_dst: neigh_node->addr, |
1422 | eth_src: ethhdr->h_source, in_nc_node: nc_node); |
1423 | |
1424 | /* Opportunity was found, so stop searching */ |
1425 | if (nc_packet) |
1426 | break; |
1427 | } |
1428 | rcu_read_unlock(); |
1429 | |
1430 | if (!nc_packet) |
1431 | return false; |
1432 | |
1433 | /* Save packets for later decoding */ |
1434 | batadv_nc_skb_store_before_coding(bat_priv, skb, |
1435 | eth_dst_new: neigh_node->addr); |
1436 | batadv_nc_skb_store_before_coding(bat_priv, skb: nc_packet->skb, |
1437 | eth_dst_new: nc_packet->neigh_node->addr); |
1438 | |
1439 | /* Code and send packets */ |
1440 | if (batadv_nc_code_packets(bat_priv, skb, ethhdr, nc_packet, |
1441 | neigh_node)) |
1442 | return true; |
1443 | |
1444 | /* out of mem ? Coding failed - we have to free the buffered packet |
1445 | * to avoid memleaks. The skb passed as argument will be dealt with |
1446 | * by the calling function. |
1447 | */ |
1448 | batadv_nc_send_packet(nc_packet); |
1449 | return false; |
1450 | } |
1451 | |
1452 | /** |
1453 | * batadv_nc_skb_add_to_path() - buffer skb for later encoding / decoding |
1454 | * @skb: skb to add to path |
1455 | * @nc_path: path to add skb to |
1456 | * @neigh_node: next hop to forward packet to |
1457 | * @packet_id: checksum to identify packet |
1458 | * |
1459 | * Return: true if the packet was buffered or false in case of an error. |
1460 | */ |
1461 | static bool batadv_nc_skb_add_to_path(struct sk_buff *skb, |
1462 | struct batadv_nc_path *nc_path, |
1463 | struct batadv_neigh_node *neigh_node, |
1464 | __be32 packet_id) |
1465 | { |
1466 | struct batadv_nc_packet *nc_packet; |
1467 | |
1468 | nc_packet = kzalloc(size: sizeof(*nc_packet), GFP_ATOMIC); |
1469 | if (!nc_packet) |
1470 | return false; |
1471 | |
1472 | /* Initialize nc_packet */ |
1473 | nc_packet->timestamp = jiffies; |
1474 | nc_packet->packet_id = packet_id; |
1475 | nc_packet->skb = skb; |
1476 | nc_packet->neigh_node = neigh_node; |
1477 | nc_packet->nc_path = nc_path; |
1478 | |
1479 | /* Add coding packet to list */ |
1480 | spin_lock_bh(lock: &nc_path->packet_list_lock); |
1481 | list_add_tail(new: &nc_packet->list, head: &nc_path->packet_list); |
1482 | spin_unlock_bh(lock: &nc_path->packet_list_lock); |
1483 | |
1484 | return true; |
1485 | } |
1486 | |
1487 | /** |
1488 | * batadv_nc_skb_forward() - try to code a packet or add it to the coding packet |
1489 | * buffer |
1490 | * @skb: data skb to forward |
1491 | * @neigh_node: next hop to forward packet to |
1492 | * |
1493 | * Return: true if the skb was consumed (encoded packet sent) or false otherwise |
1494 | */ |
1495 | bool batadv_nc_skb_forward(struct sk_buff *skb, |
1496 | struct batadv_neigh_node *neigh_node) |
1497 | { |
1498 | const struct net_device *netdev = neigh_node->if_incoming->soft_iface; |
1499 | struct batadv_priv *bat_priv = netdev_priv(dev: netdev); |
1500 | struct batadv_unicast_packet *packet; |
1501 | struct batadv_nc_path *nc_path; |
1502 | struct ethhdr *ethhdr = eth_hdr(skb); |
1503 | __be32 packet_id; |
1504 | u8 *payload; |
1505 | |
1506 | /* Check if network coding is enabled */ |
1507 | if (!atomic_read(v: &bat_priv->network_coding)) |
1508 | goto out; |
1509 | |
1510 | /* We only handle unicast packets */ |
1511 | payload = skb_network_header(skb); |
1512 | packet = (struct batadv_unicast_packet *)payload; |
1513 | if (packet->packet_type != BATADV_UNICAST) |
1514 | goto out; |
1515 | |
1516 | /* Try to find a coding opportunity and send the skb if one is found */ |
1517 | if (batadv_nc_skb_dst_search(skb, neigh_node, ethhdr)) |
1518 | return true; |
1519 | |
1520 | /* Find or create a nc_path for this src-dst pair */ |
1521 | nc_path = batadv_nc_get_path(bat_priv, |
1522 | hash: bat_priv->nc.coding_hash, |
1523 | src: ethhdr->h_source, |
1524 | dst: neigh_node->addr); |
1525 | |
1526 | if (!nc_path) |
1527 | goto out; |
1528 | |
1529 | /* Add skb to nc_path */ |
1530 | packet_id = batadv_skb_crc32(skb, payload_ptr: payload + sizeof(*packet)); |
1531 | if (!batadv_nc_skb_add_to_path(skb, nc_path, neigh_node, packet_id)) |
1532 | goto free_nc_path; |
1533 | |
1534 | /* Packet is consumed */ |
1535 | return true; |
1536 | |
1537 | free_nc_path: |
1538 | batadv_nc_path_put(nc_path); |
1539 | out: |
1540 | /* Packet is not consumed */ |
1541 | return false; |
1542 | } |
1543 | |
1544 | /** |
1545 | * batadv_nc_skb_store_for_decoding() - save a clone of the skb which can be |
1546 | * used when decoding coded packets |
1547 | * @bat_priv: the bat priv with all the soft interface information |
1548 | * @skb: data skb to store |
1549 | */ |
1550 | void batadv_nc_skb_store_for_decoding(struct batadv_priv *bat_priv, |
1551 | struct sk_buff *skb) |
1552 | { |
1553 | struct batadv_unicast_packet *packet; |
1554 | struct batadv_nc_path *nc_path; |
1555 | struct ethhdr *ethhdr = eth_hdr(skb); |
1556 | __be32 packet_id; |
1557 | u8 *payload; |
1558 | |
1559 | /* Check if network coding is enabled */ |
1560 | if (!atomic_read(v: &bat_priv->network_coding)) |
1561 | goto out; |
1562 | |
1563 | /* Check for supported packet type */ |
1564 | payload = skb_network_header(skb); |
1565 | packet = (struct batadv_unicast_packet *)payload; |
1566 | if (packet->packet_type != BATADV_UNICAST) |
1567 | goto out; |
1568 | |
1569 | /* Find existing nc_path or create a new */ |
1570 | nc_path = batadv_nc_get_path(bat_priv, |
1571 | hash: bat_priv->nc.decoding_hash, |
1572 | src: ethhdr->h_source, |
1573 | dst: ethhdr->h_dest); |
1574 | |
1575 | if (!nc_path) |
1576 | goto out; |
1577 | |
1578 | /* Clone skb and adjust skb->data to point at batman header */ |
1579 | skb = skb_clone(skb, GFP_ATOMIC); |
1580 | if (unlikely(!skb)) |
1581 | goto free_nc_path; |
1582 | |
1583 | if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) |
1584 | goto free_skb; |
1585 | |
1586 | if (unlikely(!skb_pull_rcsum(skb, ETH_HLEN))) |
1587 | goto free_skb; |
1588 | |
1589 | /* Add skb to nc_path */ |
1590 | packet_id = batadv_skb_crc32(skb, payload_ptr: payload + sizeof(*packet)); |
1591 | if (!batadv_nc_skb_add_to_path(skb, nc_path, NULL, packet_id)) |
1592 | goto free_skb; |
1593 | |
1594 | batadv_inc_counter(bat_priv, BATADV_CNT_NC_BUFFER); |
1595 | return; |
1596 | |
1597 | free_skb: |
1598 | kfree_skb(skb); |
1599 | free_nc_path: |
1600 | batadv_nc_path_put(nc_path); |
1601 | out: |
1602 | return; |
1603 | } |
1604 | |
1605 | /** |
1606 | * batadv_nc_skb_store_sniffed_unicast() - check if a received unicast packet |
1607 | * should be saved in the decoding buffer and, if so, store it there |
1608 | * @bat_priv: the bat priv with all the soft interface information |
1609 | * @skb: unicast skb to store |
1610 | */ |
1611 | void batadv_nc_skb_store_sniffed_unicast(struct batadv_priv *bat_priv, |
1612 | struct sk_buff *skb) |
1613 | { |
1614 | struct ethhdr *ethhdr = eth_hdr(skb); |
1615 | |
1616 | if (batadv_is_my_mac(bat_priv, addr: ethhdr->h_dest)) |
1617 | return; |
1618 | |
1619 | /* Set data pointer to MAC header to mimic packets from our tx path */ |
1620 | skb_push(skb, ETH_HLEN); |
1621 | |
1622 | batadv_nc_skb_store_for_decoding(bat_priv, skb); |
1623 | } |
1624 | |
1625 | /** |
1626 | * batadv_nc_skb_decode_packet() - decode given skb using the decode data stored |
1627 | * in nc_packet |
1628 | * @bat_priv: the bat priv with all the soft interface information |
1629 | * @skb: unicast skb to decode |
1630 | * @nc_packet: decode data needed to decode the skb |
1631 | * |
1632 | * Return: pointer to decoded unicast packet if the packet was decoded or NULL |
1633 | * in case of an error. |
1634 | */ |
1635 | static struct batadv_unicast_packet * |
1636 | batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb, |
1637 | struct batadv_nc_packet *nc_packet) |
1638 | { |
1639 | const int h_size = sizeof(struct batadv_unicast_packet); |
1640 | const int h_diff = sizeof(struct batadv_coded_packet) - h_size; |
1641 | struct batadv_unicast_packet *unicast_packet; |
1642 | struct batadv_coded_packet coded_packet_tmp; |
1643 | struct ethhdr *ethhdr, ethhdr_tmp; |
1644 | u8 *orig_dest, ttl, ttvn; |
1645 | unsigned int coding_len; |
1646 | int err; |
1647 | |
1648 | /* Save headers temporarily */ |
1649 | memcpy(&coded_packet_tmp, skb->data, sizeof(coded_packet_tmp)); |
1650 | memcpy(ðhdr_tmp, skb_mac_header(skb), sizeof(ethhdr_tmp)); |
1651 | |
1652 | if (skb_cow(skb, headroom: 0) < 0) |
1653 | return NULL; |
1654 | |
1655 | if (unlikely(!skb_pull_rcsum(skb, h_diff))) |
1656 | return NULL; |
1657 | |
1658 | /* Data points to batman header, so set mac header 14 bytes before |
1659 | * and network to data |
1660 | */ |
1661 | skb_set_mac_header(skb, offset: -ETH_HLEN); |
1662 | skb_reset_network_header(skb); |
1663 | |
1664 | /* Reconstruct original mac header */ |
1665 | ethhdr = eth_hdr(skb); |
1666 | *ethhdr = ethhdr_tmp; |
1667 | |
1668 | /* Select the correct unicast header information based on the location |
1669 | * of our mac address in the coded_packet header |
1670 | */ |
1671 | if (batadv_is_my_mac(bat_priv, addr: coded_packet_tmp.second_dest)) { |
1672 | /* If we are the second destination the packet was overheard, |
1673 | * so the Ethernet address must be copied to h_dest and |
1674 | * pkt_type changed from PACKET_OTHERHOST to PACKET_HOST |
1675 | */ |
1676 | ether_addr_copy(dst: ethhdr->h_dest, src: coded_packet_tmp.second_dest); |
1677 | skb->pkt_type = PACKET_HOST; |
1678 | |
1679 | orig_dest = coded_packet_tmp.second_orig_dest; |
1680 | ttl = coded_packet_tmp.second_ttl; |
1681 | ttvn = coded_packet_tmp.second_ttvn; |
1682 | } else { |
1683 | orig_dest = coded_packet_tmp.first_orig_dest; |
1684 | ttl = coded_packet_tmp.ttl; |
1685 | ttvn = coded_packet_tmp.first_ttvn; |
1686 | } |
1687 | |
1688 | coding_len = ntohs(coded_packet_tmp.coded_len); |
1689 | |
1690 | if (coding_len > skb->len) |
1691 | return NULL; |
1692 | |
1693 | /* Here the magic is reversed: |
1694 | * extract the missing packet from the received coded packet |
1695 | */ |
1696 | batadv_nc_memxor(dst: skb->data + h_size, |
1697 | src: nc_packet->skb->data + h_size, |
1698 | len: coding_len); |
1699 | |
1700 | /* Resize decoded skb if decoded with larger packet */ |
1701 | if (nc_packet->skb->len > coding_len + h_size) { |
1702 | err = pskb_trim_rcsum(skb, len: coding_len + h_size); |
1703 | if (err) |
1704 | return NULL; |
1705 | } |
1706 | |
1707 | /* Create decoded unicast packet */ |
1708 | unicast_packet = (struct batadv_unicast_packet *)skb->data; |
1709 | unicast_packet->packet_type = BATADV_UNICAST; |
1710 | unicast_packet->version = BATADV_COMPAT_VERSION; |
1711 | unicast_packet->ttl = ttl; |
1712 | ether_addr_copy(dst: unicast_packet->dest, src: orig_dest); |
1713 | unicast_packet->ttvn = ttvn; |
1714 | |
1715 | batadv_nc_packet_free(nc_packet, dropped: false); |
1716 | return unicast_packet; |
1717 | } |
1718 | |
1719 | /** |
1720 | * batadv_nc_find_decoding_packet() - search through buffered decoding data to |
1721 | * find the data needed to decode the coded packet |
1722 | * @bat_priv: the bat priv with all the soft interface information |
1723 | * @ethhdr: pointer to the ethernet header inside the coded packet |
1724 | * @coded: coded packet we try to find decode data for |
1725 | * |
1726 | * Return: pointer to nc packet if the needed data was found or NULL otherwise. |
1727 | */ |
1728 | static struct batadv_nc_packet * |
1729 | batadv_nc_find_decoding_packet(struct batadv_priv *bat_priv, |
1730 | struct ethhdr *ethhdr, |
1731 | struct batadv_coded_packet *coded) |
1732 | { |
1733 | struct batadv_hashtable *hash = bat_priv->nc.decoding_hash; |
1734 | struct batadv_nc_packet *tmp_nc_packet, *nc_packet = NULL; |
1735 | struct batadv_nc_path *nc_path, nc_path_key; |
1736 | u8 *dest, *source; |
1737 | __be32 packet_id; |
1738 | int index; |
1739 | |
1740 | if (!hash) |
1741 | return NULL; |
1742 | |
1743 | /* Select the correct packet id based on the location of our mac-addr */ |
1744 | dest = ethhdr->h_source; |
1745 | if (!batadv_is_my_mac(bat_priv, addr: coded->second_dest)) { |
1746 | source = coded->second_source; |
1747 | packet_id = coded->second_crc; |
1748 | } else { |
1749 | source = coded->first_source; |
1750 | packet_id = coded->first_crc; |
1751 | } |
1752 | |
1753 | batadv_nc_hash_key_gen(key: &nc_path_key, src: source, dst: dest); |
1754 | index = batadv_nc_hash_choose(data: &nc_path_key, size: hash->size); |
1755 | |
1756 | /* Search for matching coding path */ |
1757 | rcu_read_lock(); |
1758 | hlist_for_each_entry_rcu(nc_path, &hash->table[index], hash_entry) { |
1759 | /* Find matching nc_packet */ |
1760 | spin_lock_bh(lock: &nc_path->packet_list_lock); |
1761 | list_for_each_entry(tmp_nc_packet, |
1762 | &nc_path->packet_list, list) { |
1763 | if (packet_id == tmp_nc_packet->packet_id) { |
1764 | list_del(entry: &tmp_nc_packet->list); |
1765 | |
1766 | nc_packet = tmp_nc_packet; |
1767 | break; |
1768 | } |
1769 | } |
1770 | spin_unlock_bh(lock: &nc_path->packet_list_lock); |
1771 | |
1772 | if (nc_packet) |
1773 | break; |
1774 | } |
1775 | rcu_read_unlock(); |
1776 | |
1777 | if (!nc_packet) |
1778 | batadv_dbg(BATADV_DBG_NC, bat_priv, |
1779 | "No decoding packet found for %u\n" , packet_id); |
1780 | |
1781 | return nc_packet; |
1782 | } |
1783 | |
1784 | /** |
1785 | * batadv_nc_recv_coded_packet() - try to decode coded packet and enqueue the |
1786 | * resulting unicast packet |
1787 | * @skb: incoming coded packet |
1788 | * @recv_if: pointer to interface this packet was received on |
1789 | * |
1790 | * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP |
1791 | * otherwise. |
1792 | */ |
1793 | static int batadv_nc_recv_coded_packet(struct sk_buff *skb, |
1794 | struct batadv_hard_iface *recv_if) |
1795 | { |
1796 | struct batadv_priv *bat_priv = netdev_priv(dev: recv_if->soft_iface); |
1797 | struct batadv_unicast_packet *unicast_packet; |
1798 | struct batadv_coded_packet *coded_packet; |
1799 | struct batadv_nc_packet *nc_packet; |
1800 | struct ethhdr *ethhdr; |
1801 | int hdr_size = sizeof(*coded_packet); |
1802 | |
1803 | /* Check if network coding is enabled */ |
1804 | if (!atomic_read(v: &bat_priv->network_coding)) |
1805 | goto free_skb; |
1806 | |
1807 | /* Make sure we can access (and remove) header */ |
1808 | if (unlikely(!pskb_may_pull(skb, hdr_size))) |
1809 | goto free_skb; |
1810 | |
1811 | coded_packet = (struct batadv_coded_packet *)skb->data; |
1812 | ethhdr = eth_hdr(skb); |
1813 | |
1814 | /* Verify frame is destined for us */ |
1815 | if (!batadv_is_my_mac(bat_priv, addr: ethhdr->h_dest) && |
1816 | !batadv_is_my_mac(bat_priv, addr: coded_packet->second_dest)) |
1817 | goto free_skb; |
1818 | |
1819 | /* Update stat counter */ |
1820 | if (batadv_is_my_mac(bat_priv, addr: coded_packet->second_dest)) |
1821 | batadv_inc_counter(bat_priv, BATADV_CNT_NC_SNIFFED); |
1822 | |
1823 | nc_packet = batadv_nc_find_decoding_packet(bat_priv, ethhdr, |
1824 | coded: coded_packet); |
1825 | if (!nc_packet) { |
1826 | batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED); |
1827 | goto free_skb; |
1828 | } |
1829 | |
1830 | /* Make skb's linear, because decoding accesses the entire buffer */ |
1831 | if (skb_linearize(skb) < 0) |
1832 | goto free_nc_packet; |
1833 | |
1834 | if (skb_linearize(skb: nc_packet->skb) < 0) |
1835 | goto free_nc_packet; |
1836 | |
1837 | /* Decode the packet */ |
1838 | unicast_packet = batadv_nc_skb_decode_packet(bat_priv, skb, nc_packet); |
1839 | if (!unicast_packet) { |
1840 | batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE_FAILED); |
1841 | goto free_nc_packet; |
1842 | } |
1843 | |
1844 | /* Mark packet as decoded to do correct recoding when forwarding */ |
1845 | BATADV_SKB_CB(skb)->decoded = true; |
1846 | batadv_inc_counter(bat_priv, BATADV_CNT_NC_DECODE); |
1847 | batadv_add_counter(bat_priv, idx: BATADV_CNT_NC_DECODE_BYTES, |
1848 | count: skb->len + ETH_HLEN); |
1849 | return batadv_recv_unicast_packet(skb, recv_if); |
1850 | |
1851 | free_nc_packet: |
1852 | batadv_nc_packet_free(nc_packet, dropped: true); |
1853 | free_skb: |
1854 | kfree_skb(skb); |
1855 | |
1856 | return NET_RX_DROP; |
1857 | } |
1858 | |
1859 | /** |
1860 | * batadv_nc_mesh_free() - clean up network coding memory |
1861 | * @bat_priv: the bat priv with all the soft interface information |
1862 | */ |
1863 | void batadv_nc_mesh_free(struct batadv_priv *bat_priv) |
1864 | { |
1865 | batadv_tvlv_container_unregister(bat_priv, type: BATADV_TVLV_NC, version: 1); |
1866 | batadv_tvlv_handler_unregister(bat_priv, type: BATADV_TVLV_NC, version: 1); |
1867 | cancel_delayed_work_sync(dwork: &bat_priv->nc.work); |
1868 | |
1869 | batadv_nc_purge_paths(bat_priv, hash: bat_priv->nc.coding_hash, NULL); |
1870 | batadv_hash_destroy(hash: bat_priv->nc.coding_hash); |
1871 | batadv_nc_purge_paths(bat_priv, hash: bat_priv->nc.decoding_hash, NULL); |
1872 | batadv_hash_destroy(hash: bat_priv->nc.decoding_hash); |
1873 | } |
1874 | |