blob: 06345d401588c949762edfa14aaeb3f018a8e294 [file] [log] [blame]
Antonio Quartulli0b873932013-01-04 03:05:31 +01001/* Copyright (C) 2011-2013 B.A.T.M.A.N. contributors:
Antonio Quartulli785ea112011-11-23 11:35:44 +01002 *
3 * Antonio Quartulli
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of version 2 of the GNU General Public
7 * License as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA
18 */
19
20#include <linux/if_ether.h>
21#include <linux/if_arp.h>
Antonio Quartullic384ea32011-06-26 03:37:18 +020022#include <net/arp.h>
Antonio Quartulli785ea112011-11-23 11:35:44 +010023
24#include "main.h"
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +020025#include "hash.h"
Antonio Quartulli785ea112011-11-23 11:35:44 +010026#include "distributed-arp-table.h"
27#include "hard-interface.h"
28#include "originator.h"
29#include "send.h"
30#include "types.h"
Antonio Quartullic384ea32011-06-26 03:37:18 +020031#include "translation-table.h"
Antonio Quartulli785ea112011-11-23 11:35:44 +010032#include "unicast.h"
33
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +020034static void batadv_dat_purge(struct work_struct *work);
35
36/**
37 * batadv_dat_start_timer - initialise the DAT periodic worker
38 * @bat_priv: the bat priv with all the soft interface information
39 */
40static void batadv_dat_start_timer(struct batadv_priv *bat_priv)
41{
42 INIT_DELAYED_WORK(&bat_priv->dat.work, batadv_dat_purge);
43 queue_delayed_work(batadv_event_workqueue, &bat_priv->dat.work,
44 msecs_to_jiffies(10000));
45}
46
47/**
Marek Lindner93178012013-03-10 19:29:15 +080048 * batadv_dat_entry_free_ref - decrement the dat_entry refcounter and possibly
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +020049 * free it
Marek Lindner93178012013-03-10 19:29:15 +080050 * @dat_entry: the entry to free
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +020051 */
52static void batadv_dat_entry_free_ref(struct batadv_dat_entry *dat_entry)
53{
54 if (atomic_dec_and_test(&dat_entry->refcount))
55 kfree_rcu(dat_entry, rcu);
56}
57
58/**
Marek Lindner93178012013-03-10 19:29:15 +080059 * batadv_dat_to_purge - check whether a dat_entry has to be purged or not
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +020060 * @dat_entry: the entry to check
61 *
Marek Lindner93178012013-03-10 19:29:15 +080062 * Returns true if the entry has to be purged now, false otherwise.
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +020063 */
64static bool batadv_dat_to_purge(struct batadv_dat_entry *dat_entry)
65{
66 return batadv_has_timed_out(dat_entry->last_update,
67 BATADV_DAT_ENTRY_TIMEOUT);
68}
69
70/**
71 * __batadv_dat_purge - delete entries from the DAT local storage
72 * @bat_priv: the bat priv with all the soft interface information
73 * @to_purge: function in charge to decide whether an entry has to be purged or
74 * not. This function takes the dat_entry as argument and has to
75 * returns a boolean value: true is the entry has to be deleted,
76 * false otherwise
77 *
Marek Lindner93178012013-03-10 19:29:15 +080078 * Loops over each entry in the DAT local storage and deletes it if and only if
79 * the to_purge function passed as argument returns true.
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +020080 */
81static void __batadv_dat_purge(struct batadv_priv *bat_priv,
82 bool (*to_purge)(struct batadv_dat_entry *))
83{
84 spinlock_t *list_lock; /* protects write access to the hash lists */
85 struct batadv_dat_entry *dat_entry;
Sasha Levinb67bfe02013-02-27 17:06:00 -080086 struct hlist_node *node_tmp;
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +020087 struct hlist_head *head;
88 uint32_t i;
89
90 if (!bat_priv->dat.hash)
91 return;
92
93 for (i = 0; i < bat_priv->dat.hash->size; i++) {
94 head = &bat_priv->dat.hash->table[i];
95 list_lock = &bat_priv->dat.hash->list_locks[i];
96
97 spin_lock_bh(list_lock);
Sasha Levinb67bfe02013-02-27 17:06:00 -080098 hlist_for_each_entry_safe(dat_entry, node_tmp, head,
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +020099 hash_entry) {
Marek Lindner93178012013-03-10 19:29:15 +0800100 /* if a helper function has been passed as parameter,
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200101 * ask it if the entry has to be purged or not
102 */
103 if (to_purge && !to_purge(dat_entry))
104 continue;
105
Sasha Levinb67bfe02013-02-27 17:06:00 -0800106 hlist_del_rcu(&dat_entry->hash_entry);
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200107 batadv_dat_entry_free_ref(dat_entry);
108 }
109 spin_unlock_bh(list_lock);
110 }
111}
112
113/**
114 * batadv_dat_purge - periodic task that deletes old entries from the local DAT
115 * hash table
116 * @work: kernel work struct
117 */
118static void batadv_dat_purge(struct work_struct *work)
119{
120 struct delayed_work *delayed_work;
121 struct batadv_priv_dat *priv_dat;
122 struct batadv_priv *bat_priv;
123
124 delayed_work = container_of(work, struct delayed_work, work);
125 priv_dat = container_of(delayed_work, struct batadv_priv_dat, work);
126 bat_priv = container_of(priv_dat, struct batadv_priv, dat);
127
128 __batadv_dat_purge(bat_priv, batadv_dat_to_purge);
129 batadv_dat_start_timer(bat_priv);
130}
131
132/**
133 * batadv_compare_dat - comparing function used in the local DAT hash table
134 * @node: node in the local table
135 * @data2: second object to compare the node to
136 *
Marek Lindner93178012013-03-10 19:29:15 +0800137 * Returns 1 if the two entries are the same, 0 otherwise.
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200138 */
139static int batadv_compare_dat(const struct hlist_node *node, const void *data2)
140{
141 const void *data1 = container_of(node, struct batadv_dat_entry,
142 hash_entry);
143
144 return (memcmp(data1, data2, sizeof(__be32)) == 0 ? 1 : 0);
145}
146
Antonio Quartulli785ea112011-11-23 11:35:44 +0100147/**
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200148 * batadv_arp_hw_src - extract the hw_src field from an ARP packet
149 * @skb: ARP packet
150 * @hdr_size: size of the possible header before the ARP packet
151 *
Marek Lindner93178012013-03-10 19:29:15 +0800152 * Returns the value of the hw_src field in the ARP packet.
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200153 */
154static uint8_t *batadv_arp_hw_src(struct sk_buff *skb, int hdr_size)
155{
156 uint8_t *addr;
157
158 addr = (uint8_t *)(skb->data + hdr_size);
159 addr += ETH_HLEN + sizeof(struct arphdr);
160
161 return addr;
162}
163
164/**
165 * batadv_arp_ip_src - extract the ip_src field from an ARP packet
166 * @skb: ARP packet
167 * @hdr_size: size of the possible header before the ARP packet
168 *
Marek Lindner93178012013-03-10 19:29:15 +0800169 * Returns the value of the ip_src field in the ARP packet.
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200170 */
171static __be32 batadv_arp_ip_src(struct sk_buff *skb, int hdr_size)
172{
173 return *(__be32 *)(batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN);
174}
175
176/**
177 * batadv_arp_hw_dst - extract the hw_dst field from an ARP packet
178 * @skb: ARP packet
179 * @hdr_size: size of the possible header before the ARP packet
180 *
Marek Lindner93178012013-03-10 19:29:15 +0800181 * Returns the value of the hw_dst field in the ARP packet.
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200182 */
183static uint8_t *batadv_arp_hw_dst(struct sk_buff *skb, int hdr_size)
184{
185 return batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN + 4;
186}
187
188/**
189 * batadv_arp_ip_dst - extract the ip_dst field from an ARP packet
190 * @skb: ARP packet
191 * @hdr_size: size of the possible header before the ARP packet
192 *
Marek Lindner93178012013-03-10 19:29:15 +0800193 * Returns the value of the ip_dst field in the ARP packet.
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200194 */
195static __be32 batadv_arp_ip_dst(struct sk_buff *skb, int hdr_size)
196{
197 return *(__be32 *)(batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN * 2 + 4);
198}
199
200/**
Antonio Quartulli785ea112011-11-23 11:35:44 +0100201 * batadv_hash_dat - compute the hash value for an IP address
202 * @data: data to hash
203 * @size: size of the hash table
204 *
Marek Lindner93178012013-03-10 19:29:15 +0800205 * Returns the selected index in the hash table for the given data.
Antonio Quartulli785ea112011-11-23 11:35:44 +0100206 */
207static uint32_t batadv_hash_dat(const void *data, uint32_t size)
208{
209 const unsigned char *key = data;
210 uint32_t hash = 0;
211 size_t i;
212
213 for (i = 0; i < 4; i++) {
214 hash += key[i];
215 hash += (hash << 10);
216 hash ^= (hash >> 6);
217 }
218
219 hash += (hash << 3);
220 hash ^= (hash >> 11);
221 hash += (hash << 15);
222
223 return hash % size;
224}
225
226/**
Marek Lindner93178012013-03-10 19:29:15 +0800227 * batadv_dat_entry_hash_find - look for a given dat_entry in the local hash
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200228 * table
229 * @bat_priv: the bat priv with all the soft interface information
230 * @ip: search key
231 *
Marek Lindner93178012013-03-10 19:29:15 +0800232 * Returns the dat_entry if found, NULL otherwise.
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200233 */
234static struct batadv_dat_entry *
235batadv_dat_entry_hash_find(struct batadv_priv *bat_priv, __be32 ip)
236{
237 struct hlist_head *head;
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200238 struct batadv_dat_entry *dat_entry, *dat_entry_tmp = NULL;
239 struct batadv_hashtable *hash = bat_priv->dat.hash;
240 uint32_t index;
241
242 if (!hash)
243 return NULL;
244
245 index = batadv_hash_dat(&ip, hash->size);
246 head = &hash->table[index];
247
248 rcu_read_lock();
Sasha Levinb67bfe02013-02-27 17:06:00 -0800249 hlist_for_each_entry_rcu(dat_entry, head, hash_entry) {
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200250 if (dat_entry->ip != ip)
251 continue;
252
253 if (!atomic_inc_not_zero(&dat_entry->refcount))
254 continue;
255
256 dat_entry_tmp = dat_entry;
257 break;
258 }
259 rcu_read_unlock();
260
261 return dat_entry_tmp;
262}
263
264/**
265 * batadv_dat_entry_add - add a new dat entry or update it if already exists
266 * @bat_priv: the bat priv with all the soft interface information
267 * @ip: ipv4 to add/edit
268 * @mac_addr: mac address to assign to the given ipv4
269 */
270static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip,
271 uint8_t *mac_addr)
272{
273 struct batadv_dat_entry *dat_entry;
274 int hash_added;
275
276 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip);
277 /* if this entry is already known, just update it */
278 if (dat_entry) {
279 if (!batadv_compare_eth(dat_entry->mac_addr, mac_addr))
280 memcpy(dat_entry->mac_addr, mac_addr, ETH_ALEN);
281 dat_entry->last_update = jiffies;
282 batadv_dbg(BATADV_DBG_DAT, bat_priv,
283 "Entry updated: %pI4 %pM\n", &dat_entry->ip,
284 dat_entry->mac_addr);
285 goto out;
286 }
287
288 dat_entry = kmalloc(sizeof(*dat_entry), GFP_ATOMIC);
289 if (!dat_entry)
290 goto out;
291
292 dat_entry->ip = ip;
293 memcpy(dat_entry->mac_addr, mac_addr, ETH_ALEN);
294 dat_entry->last_update = jiffies;
295 atomic_set(&dat_entry->refcount, 2);
296
297 hash_added = batadv_hash_add(bat_priv->dat.hash, batadv_compare_dat,
298 batadv_hash_dat, &dat_entry->ip,
299 &dat_entry->hash_entry);
300
301 if (unlikely(hash_added != 0)) {
302 /* remove the reference for the hash */
303 batadv_dat_entry_free_ref(dat_entry);
304 goto out;
305 }
306
307 batadv_dbg(BATADV_DBG_DAT, bat_priv, "New entry added: %pI4 %pM\n",
308 &dat_entry->ip, dat_entry->mac_addr);
309
310out:
311 if (dat_entry)
312 batadv_dat_entry_free_ref(dat_entry);
313}
314
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200315#ifdef CONFIG_BATMAN_ADV_DEBUG
316
317/**
318 * batadv_dbg_arp - print a debug message containing all the ARP packet details
319 * @bat_priv: the bat priv with all the soft interface information
320 * @skb: ARP packet
321 * @type: ARP type
322 * @hdr_size: size of the possible header before the ARP packet
323 * @msg: message to print together with the debugging information
324 */
325static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb,
326 uint16_t type, int hdr_size, char *msg)
327{
328 struct batadv_unicast_4addr_packet *unicast_4addr_packet;
329 struct batadv_bcast_packet *bcast_pkt;
330 uint8_t *orig_addr;
331 __be32 ip_src, ip_dst;
332
333 if (msg)
334 batadv_dbg(BATADV_DBG_DAT, bat_priv, "%s\n", msg);
335
336 ip_src = batadv_arp_ip_src(skb, hdr_size);
337 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
338 batadv_dbg(BATADV_DBG_DAT, bat_priv,
339 "ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]\n",
340 batadv_arp_hw_src(skb, hdr_size), &ip_src,
341 batadv_arp_hw_dst(skb, hdr_size), &ip_dst);
342
343 if (hdr_size == 0)
344 return;
345
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200346 unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
347
348 switch (unicast_4addr_packet->u.header.packet_type) {
349 case BATADV_UNICAST:
350 batadv_dbg(BATADV_DBG_DAT, bat_priv,
351 "* encapsulated within a UNICAST packet\n");
352 break;
353 case BATADV_UNICAST_4ADDR:
354 batadv_dbg(BATADV_DBG_DAT, bat_priv,
355 "* encapsulated within a UNICAST_4ADDR packet (src: %pM)\n",
356 unicast_4addr_packet->src);
357 switch (unicast_4addr_packet->subtype) {
358 case BATADV_P_DAT_DHT_PUT:
359 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_PUT\n");
360 break;
361 case BATADV_P_DAT_DHT_GET:
362 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_GET\n");
363 break;
364 case BATADV_P_DAT_CACHE_REPLY:
365 batadv_dbg(BATADV_DBG_DAT, bat_priv,
366 "* type: DAT_CACHE_REPLY\n");
367 break;
368 case BATADV_P_DATA:
369 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DATA\n");
370 break;
371 default:
372 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: Unknown (%u)!\n",
373 unicast_4addr_packet->u.header.packet_type);
374 }
375 break;
376 case BATADV_BCAST:
377 bcast_pkt = (struct batadv_bcast_packet *)unicast_4addr_packet;
378 orig_addr = bcast_pkt->orig;
379 batadv_dbg(BATADV_DBG_DAT, bat_priv,
380 "* encapsulated within a BCAST packet (src: %pM)\n",
381 orig_addr);
382 break;
383 default:
384 batadv_dbg(BATADV_DBG_DAT, bat_priv,
385 "* encapsulated within an unknown packet type (0x%x)\n",
386 unicast_4addr_packet->u.header.packet_type);
387 }
388}
389
390#else
391
392static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb,
393 uint16_t type, int hdr_size, char *msg)
394{
395}
396
397#endif /* CONFIG_BATMAN_ADV_DEBUG */
398
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200399/**
Antonio Quartulli785ea112011-11-23 11:35:44 +0100400 * batadv_is_orig_node_eligible - check whether a node can be a DHT candidate
401 * @res: the array with the already selected candidates
402 * @select: number of already selected candidates
403 * @tmp_max: address of the currently evaluated node
404 * @max: current round max address
405 * @last_max: address of the last selected candidate
406 * @candidate: orig_node under evaluation
407 * @max_orig_node: last selected candidate
408 *
Marek Lindner93178012013-03-10 19:29:15 +0800409 * Returns true if the node has been elected as next candidate or false
410 * otherwise.
Antonio Quartulli785ea112011-11-23 11:35:44 +0100411 */
412static bool batadv_is_orig_node_eligible(struct batadv_dat_candidate *res,
413 int select, batadv_dat_addr_t tmp_max,
414 batadv_dat_addr_t max,
415 batadv_dat_addr_t last_max,
416 struct batadv_orig_node *candidate,
417 struct batadv_orig_node *max_orig_node)
418{
419 bool ret = false;
420 int j;
421
422 /* Check if this node has already been selected... */
423 for (j = 0; j < select; j++)
424 if (res[j].orig_node == candidate)
425 break;
426 /* ..and possibly skip it */
427 if (j < select)
428 goto out;
429 /* sanity check: has it already been selected? This should not happen */
430 if (tmp_max > last_max)
431 goto out;
432 /* check if during this iteration an originator with a closer dht
433 * address has already been found
434 */
435 if (tmp_max < max)
436 goto out;
437 /* this is an hash collision with the temporary selected node. Choose
438 * the one with the lowest address
439 */
Pau Koning816cd5b2013-02-12 00:18:45 +0000440 if ((tmp_max == max) && max_orig_node &&
Antonio Quartulli785ea112011-11-23 11:35:44 +0100441 (batadv_compare_eth(candidate->orig, max_orig_node->orig) > 0))
442 goto out;
443
444 ret = true;
445out:
446 return ret;
447}
448
449/**
450 * batadv_choose_next_candidate - select the next DHT candidate
451 * @bat_priv: the bat priv with all the soft interface information
452 * @cands: candidates array
453 * @select: number of candidates already present in the array
454 * @ip_key: key to look up in the DHT
455 * @last_max: pointer where the address of the selected candidate will be saved
456 */
457static void batadv_choose_next_candidate(struct batadv_priv *bat_priv,
458 struct batadv_dat_candidate *cands,
459 int select, batadv_dat_addr_t ip_key,
460 batadv_dat_addr_t *last_max)
461{
462 batadv_dat_addr_t max = 0, tmp_max = 0;
463 struct batadv_orig_node *orig_node, *max_orig_node = NULL;
464 struct batadv_hashtable *hash = bat_priv->orig_hash;
Antonio Quartulli785ea112011-11-23 11:35:44 +0100465 struct hlist_head *head;
466 int i;
467
468 /* if no node is eligible as candidate, leave the candidate type as
469 * NOT_FOUND
470 */
471 cands[select].type = BATADV_DAT_CANDIDATE_NOT_FOUND;
472
Marek Lindner93178012013-03-10 19:29:15 +0800473 /* iterate over the originator list and find the node with the closest
Antonio Quartulli785ea112011-11-23 11:35:44 +0100474 * dat_address which has not been selected yet
475 */
476 for (i = 0; i < hash->size; i++) {
477 head = &hash->table[i];
478
479 rcu_read_lock();
Sasha Levinb67bfe02013-02-27 17:06:00 -0800480 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
Marek Lindner93178012013-03-10 19:29:15 +0800481 /* the dht space is a ring using unsigned addresses */
Antonio Quartulli785ea112011-11-23 11:35:44 +0100482 tmp_max = BATADV_DAT_ADDR_MAX - orig_node->dat_addr +
483 ip_key;
484
485 if (!batadv_is_orig_node_eligible(cands, select,
486 tmp_max, max,
487 *last_max, orig_node,
488 max_orig_node))
489 continue;
490
491 if (!atomic_inc_not_zero(&orig_node->refcount))
492 continue;
493
494 max = tmp_max;
495 if (max_orig_node)
496 batadv_orig_node_free_ref(max_orig_node);
497 max_orig_node = orig_node;
498 }
499 rcu_read_unlock();
500 }
501 if (max_orig_node) {
502 cands[select].type = BATADV_DAT_CANDIDATE_ORIG;
503 cands[select].orig_node = max_orig_node;
504 batadv_dbg(BATADV_DBG_DAT, bat_priv,
505 "dat_select_candidates() %d: selected %pM addr=%u dist=%u\n",
506 select, max_orig_node->orig, max_orig_node->dat_addr,
507 max);
508 }
509 *last_max = max;
510}
511
512/**
Marek Lindner93178012013-03-10 19:29:15 +0800513 * batadv_dat_select_candidates - select the nodes which the DHT message has to
Antonio Quartulli785ea112011-11-23 11:35:44 +0100514 * be sent to
515 * @bat_priv: the bat priv with all the soft interface information
516 * @ip_dst: ipv4 to look up in the DHT
517 *
518 * An originator O is selected if and only if its DHT_ID value is one of three
519 * closest values (from the LEFT, with wrap around if needed) then the hash
520 * value of the key. ip_dst is the key.
521 *
Marek Lindner93178012013-03-10 19:29:15 +0800522 * Returns the candidate array of size BATADV_DAT_CANDIDATE_NUM.
Antonio Quartulli785ea112011-11-23 11:35:44 +0100523 */
524static struct batadv_dat_candidate *
525batadv_dat_select_candidates(struct batadv_priv *bat_priv, __be32 ip_dst)
526{
527 int select;
528 batadv_dat_addr_t last_max = BATADV_DAT_ADDR_MAX, ip_key;
529 struct batadv_dat_candidate *res;
530
531 if (!bat_priv->orig_hash)
532 return NULL;
533
534 res = kmalloc(BATADV_DAT_CANDIDATES_NUM * sizeof(*res), GFP_ATOMIC);
535 if (!res)
536 return NULL;
537
538 ip_key = (batadv_dat_addr_t)batadv_hash_dat(&ip_dst,
539 BATADV_DAT_ADDR_MAX);
540
541 batadv_dbg(BATADV_DBG_DAT, bat_priv,
542 "dat_select_candidates(): IP=%pI4 hash(IP)=%u\n", &ip_dst,
543 ip_key);
544
545 for (select = 0; select < BATADV_DAT_CANDIDATES_NUM; select++)
546 batadv_choose_next_candidate(bat_priv, res, select, ip_key,
547 &last_max);
548
549 return res;
550}
551
552/**
553 * batadv_dat_send_data - send a payload to the selected candidates
554 * @bat_priv: the bat priv with all the soft interface information
555 * @skb: payload to send
556 * @ip: the DHT key
557 * @packet_subtype: unicast4addr packet subtype to use
558 *
Marek Lindner93178012013-03-10 19:29:15 +0800559 * This function copies the skb with pskb_copy() and is sent as unicast packet
560 * to each of the selected candidates.
Antonio Quartulli785ea112011-11-23 11:35:44 +0100561 *
Marek Lindner93178012013-03-10 19:29:15 +0800562 * Returns true if the packet is sent to at least one candidate, false
563 * otherwise.
Antonio Quartulli785ea112011-11-23 11:35:44 +0100564 */
565static bool batadv_dat_send_data(struct batadv_priv *bat_priv,
566 struct sk_buff *skb, __be32 ip,
567 int packet_subtype)
568{
569 int i;
570 bool ret = false;
571 int send_status;
572 struct batadv_neigh_node *neigh_node = NULL;
573 struct sk_buff *tmp_skb;
574 struct batadv_dat_candidate *cand;
575
576 cand = batadv_dat_select_candidates(bat_priv, ip);
577 if (!cand)
578 goto out;
579
580 batadv_dbg(BATADV_DBG_DAT, bat_priv, "DHT_SEND for %pI4\n", &ip);
581
582 for (i = 0; i < BATADV_DAT_CANDIDATES_NUM; i++) {
583 if (cand[i].type == BATADV_DAT_CANDIDATE_NOT_FOUND)
584 continue;
585
586 neigh_node = batadv_orig_node_get_router(cand[i].orig_node);
587 if (!neigh_node)
588 goto free_orig;
589
590 tmp_skb = pskb_copy(skb, GFP_ATOMIC);
591 if (!batadv_unicast_4addr_prepare_skb(bat_priv, tmp_skb,
592 cand[i].orig_node,
593 packet_subtype)) {
594 kfree_skb(tmp_skb);
595 goto free_neigh;
596 }
597
598 send_status = batadv_send_skb_packet(tmp_skb,
599 neigh_node->if_incoming,
600 neigh_node->addr);
Martin Hundebøll4046b242012-04-20 17:02:45 +0200601 if (send_status == NET_XMIT_SUCCESS) {
602 /* count the sent packet */
603 switch (packet_subtype) {
604 case BATADV_P_DAT_DHT_GET:
605 batadv_inc_counter(bat_priv,
606 BATADV_CNT_DAT_GET_TX);
607 break;
608 case BATADV_P_DAT_DHT_PUT:
609 batadv_inc_counter(bat_priv,
610 BATADV_CNT_DAT_PUT_TX);
611 break;
612 }
613
Antonio Quartulli785ea112011-11-23 11:35:44 +0100614 /* packet sent to a candidate: return true */
615 ret = true;
Martin Hundebøll4046b242012-04-20 17:02:45 +0200616 }
Antonio Quartulli785ea112011-11-23 11:35:44 +0100617free_neigh:
618 batadv_neigh_node_free_ref(neigh_node);
619free_orig:
620 batadv_orig_node_free_ref(cand[i].orig_node);
621 }
622
623out:
624 kfree(cand);
625 return ret;
626}
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200627
628/**
629 * batadv_dat_hash_free - free the local DAT hash table
630 * @bat_priv: the bat priv with all the soft interface information
631 */
632static void batadv_dat_hash_free(struct batadv_priv *bat_priv)
633{
Antonio Quartulli33af49a2012-08-08 18:50:57 +0200634 if (!bat_priv->dat.hash)
635 return;
636
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200637 __batadv_dat_purge(bat_priv, NULL);
638
639 batadv_hash_destroy(bat_priv->dat.hash);
640
641 bat_priv->dat.hash = NULL;
642}
643
644/**
645 * batadv_dat_init - initialise the DAT internals
646 * @bat_priv: the bat priv with all the soft interface information
647 */
648int batadv_dat_init(struct batadv_priv *bat_priv)
649{
650 if (bat_priv->dat.hash)
651 return 0;
652
653 bat_priv->dat.hash = batadv_hash_new(1024);
654
655 if (!bat_priv->dat.hash)
656 return -ENOMEM;
657
658 batadv_dat_start_timer(bat_priv);
659
660 return 0;
661}
662
663/**
664 * batadv_dat_free - free the DAT internals
665 * @bat_priv: the bat priv with all the soft interface information
666 */
667void batadv_dat_free(struct batadv_priv *bat_priv)
668{
669 cancel_delayed_work_sync(&bat_priv->dat.work);
670
671 batadv_dat_hash_free(bat_priv);
672}
673
674/**
675 * batadv_dat_cache_seq_print_text - print the local DAT hash table
676 * @seq: seq file to print on
677 * @offset: not used
678 */
679int batadv_dat_cache_seq_print_text(struct seq_file *seq, void *offset)
680{
681 struct net_device *net_dev = (struct net_device *)seq->private;
682 struct batadv_priv *bat_priv = netdev_priv(net_dev);
683 struct batadv_hashtable *hash = bat_priv->dat.hash;
684 struct batadv_dat_entry *dat_entry;
685 struct batadv_hard_iface *primary_if;
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200686 struct hlist_head *head;
687 unsigned long last_seen_jiffies;
688 int last_seen_msecs, last_seen_secs, last_seen_mins;
689 uint32_t i;
690
691 primary_if = batadv_seq_print_text_primary_if_get(seq);
692 if (!primary_if)
693 goto out;
694
695 seq_printf(seq, "Distributed ARP Table (%s):\n", net_dev->name);
696 seq_printf(seq, " %-7s %-13s %5s\n", "IPv4", "MAC",
697 "last-seen");
698
699 for (i = 0; i < hash->size; i++) {
700 head = &hash->table[i];
701
702 rcu_read_lock();
Sasha Levinb67bfe02013-02-27 17:06:00 -0800703 hlist_for_each_entry_rcu(dat_entry, head, hash_entry) {
Antonio Quartulli2f1dfbe2012-06-30 20:01:19 +0200704 last_seen_jiffies = jiffies - dat_entry->last_update;
705 last_seen_msecs = jiffies_to_msecs(last_seen_jiffies);
706 last_seen_mins = last_seen_msecs / 60000;
707 last_seen_msecs = last_seen_msecs % 60000;
708 last_seen_secs = last_seen_msecs / 1000;
709
710 seq_printf(seq, " * %15pI4 %14pM %6i:%02i\n",
711 &dat_entry->ip, dat_entry->mac_addr,
712 last_seen_mins, last_seen_secs);
713 }
714 rcu_read_unlock();
715 }
716
717out:
718 if (primary_if)
719 batadv_hardif_free_ref(primary_if);
720 return 0;
721}
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200722
723/**
724 * batadv_arp_get_type - parse an ARP packet and gets the type
725 * @bat_priv: the bat priv with all the soft interface information
726 * @skb: packet to analyse
727 * @hdr_size: size of the possible header before the ARP packet in the skb
728 *
Marek Lindner93178012013-03-10 19:29:15 +0800729 * Returns the ARP type if the skb contains a valid ARP packet, 0 otherwise.
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200730 */
731static uint16_t batadv_arp_get_type(struct batadv_priv *bat_priv,
732 struct sk_buff *skb, int hdr_size)
733{
734 struct arphdr *arphdr;
735 struct ethhdr *ethhdr;
736 __be32 ip_src, ip_dst;
Matthias Schifferb618ad12013-01-24 18:18:27 +0100737 uint8_t *hw_src, *hw_dst;
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200738 uint16_t type = 0;
739
740 /* pull the ethernet header */
741 if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN)))
742 goto out;
743
744 ethhdr = (struct ethhdr *)(skb->data + hdr_size);
745
746 if (ethhdr->h_proto != htons(ETH_P_ARP))
747 goto out;
748
749 /* pull the ARP payload */
750 if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN +
751 arp_hdr_len(skb->dev))))
752 goto out;
753
754 arphdr = (struct arphdr *)(skb->data + hdr_size + ETH_HLEN);
755
Marek Lindner93178012013-03-10 19:29:15 +0800756 /* check whether the ARP packet carries a valid IP information */
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200757 if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
758 goto out;
759
760 if (arphdr->ar_pro != htons(ETH_P_IP))
761 goto out;
762
763 if (arphdr->ar_hln != ETH_ALEN)
764 goto out;
765
766 if (arphdr->ar_pln != 4)
767 goto out;
768
769 /* Check for bad reply/request. If the ARP message is not sane, DAT
770 * will simply ignore it
771 */
772 ip_src = batadv_arp_ip_src(skb, hdr_size);
773 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
774 if (ipv4_is_loopback(ip_src) || ipv4_is_multicast(ip_src) ||
Matthias Schiffer757dd822013-01-24 18:18:26 +0100775 ipv4_is_loopback(ip_dst) || ipv4_is_multicast(ip_dst) ||
776 ipv4_is_zeronet(ip_src) || ipv4_is_lbcast(ip_src) ||
777 ipv4_is_zeronet(ip_dst) || ipv4_is_lbcast(ip_dst))
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200778 goto out;
779
Matthias Schifferb618ad12013-01-24 18:18:27 +0100780 hw_src = batadv_arp_hw_src(skb, hdr_size);
781 if (is_zero_ether_addr(hw_src) || is_multicast_ether_addr(hw_src))
782 goto out;
783
Marek Lindner93178012013-03-10 19:29:15 +0800784 /* don't care about the destination MAC address in ARP requests */
Matthias Schifferb618ad12013-01-24 18:18:27 +0100785 if (arphdr->ar_op != htons(ARPOP_REQUEST)) {
786 hw_dst = batadv_arp_hw_dst(skb, hdr_size);
787 if (is_zero_ether_addr(hw_dst) ||
788 is_multicast_ether_addr(hw_dst))
789 goto out;
790 }
791
Antonio Quartulli5c3a0e52011-06-02 12:29:51 +0200792 type = ntohs(arphdr->ar_op);
793out:
794 return type;
795}
Antonio Quartullic384ea32011-06-26 03:37:18 +0200796
797/**
798 * batadv_dat_snoop_outgoing_arp_request - snoop the ARP request and try to
799 * answer using DAT
800 * @bat_priv: the bat priv with all the soft interface information
801 * @skb: packet to check
802 *
803 * Returns true if the message has been sent to the dht candidates, false
Marek Lindner93178012013-03-10 19:29:15 +0800804 * otherwise. In case of a positive return value the message has to be enqueued
805 * to permit the fallback.
Antonio Quartullic384ea32011-06-26 03:37:18 +0200806 */
807bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
808 struct sk_buff *skb)
809{
810 uint16_t type = 0;
811 __be32 ip_dst, ip_src;
812 uint8_t *hw_src;
813 bool ret = false;
814 struct batadv_dat_entry *dat_entry = NULL;
815 struct sk_buff *skb_new;
Antonio Quartullic384ea32011-06-26 03:37:18 +0200816
Antonio Quartulli33af49a2012-08-08 18:50:57 +0200817 if (!atomic_read(&bat_priv->distributed_arp_table))
818 goto out;
819
Antonio Quartullic384ea32011-06-26 03:37:18 +0200820 type = batadv_arp_get_type(bat_priv, skb, 0);
821 /* If the node gets an ARP_REQUEST it has to send a DHT_GET unicast
822 * message to the selected DHT candidates
823 */
824 if (type != ARPOP_REQUEST)
825 goto out;
826
827 batadv_dbg_arp(bat_priv, skb, type, 0, "Parsing outgoing ARP REQUEST");
828
829 ip_src = batadv_arp_ip_src(skb, 0);
830 hw_src = batadv_arp_hw_src(skb, 0);
831 ip_dst = batadv_arp_ip_dst(skb, 0);
832
833 batadv_dat_entry_add(bat_priv, ip_src, hw_src);
834
835 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst);
836 if (dat_entry) {
Antonio Quartulli88e48d72013-05-09 09:35:45 +0200837 /* If the ARP request is destined for a local client the local
838 * client will answer itself. DAT would only generate a
839 * duplicate packet.
840 *
841 * Moreover, if the soft-interface is enslaved into a bridge, an
842 * additional DAT answer may trigger kernel warnings about
843 * a packet coming from the wrong port.
844 */
845 if (batadv_is_my_client(bat_priv, dat_entry->mac_addr)) {
846 ret = true;
847 goto out;
848 }
849
Antonio Quartullic384ea32011-06-26 03:37:18 +0200850 skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
Marek Lindner736292c2013-01-12 19:19:06 +0800851 bat_priv->soft_iface, ip_dst, hw_src,
Antonio Quartullic384ea32011-06-26 03:37:18 +0200852 dat_entry->mac_addr, hw_src);
853 if (!skb_new)
854 goto out;
855
856 skb_reset_mac_header(skb_new);
857 skb_new->protocol = eth_type_trans(skb_new,
Marek Lindner736292c2013-01-12 19:19:06 +0800858 bat_priv->soft_iface);
Antonio Quartullic384ea32011-06-26 03:37:18 +0200859 bat_priv->stats.rx_packets++;
860 bat_priv->stats.rx_bytes += skb->len + ETH_HLEN;
Marek Lindner736292c2013-01-12 19:19:06 +0800861 bat_priv->soft_iface->last_rx = jiffies;
Antonio Quartullic384ea32011-06-26 03:37:18 +0200862
863 netif_rx(skb_new);
864 batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP request replied locally\n");
865 ret = true;
866 } else {
Marek Lindner93178012013-03-10 19:29:15 +0800867 /* Send the request to the DHT */
Antonio Quartullic384ea32011-06-26 03:37:18 +0200868 ret = batadv_dat_send_data(bat_priv, skb, ip_dst,
869 BATADV_P_DAT_DHT_GET);
870 }
871out:
872 if (dat_entry)
873 batadv_dat_entry_free_ref(dat_entry);
Antonio Quartullic384ea32011-06-26 03:37:18 +0200874 return ret;
875}
876
877/**
878 * batadv_dat_snoop_incoming_arp_request - snoop the ARP request and try to
879 * answer using the local DAT storage
880 * @bat_priv: the bat priv with all the soft interface information
881 * @skb: packet to check
882 * @hdr_size: size of the encapsulation header
883 *
Marek Lindner93178012013-03-10 19:29:15 +0800884 * Returns true if the request has been answered, false otherwise.
Antonio Quartullic384ea32011-06-26 03:37:18 +0200885 */
886bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
887 struct sk_buff *skb, int hdr_size)
888{
889 uint16_t type;
890 __be32 ip_src, ip_dst;
891 uint8_t *hw_src;
892 struct sk_buff *skb_new;
Antonio Quartullic384ea32011-06-26 03:37:18 +0200893 struct batadv_dat_entry *dat_entry = NULL;
894 bool ret = false;
895 int err;
896
Antonio Quartulli33af49a2012-08-08 18:50:57 +0200897 if (!atomic_read(&bat_priv->distributed_arp_table))
898 goto out;
899
Antonio Quartullic384ea32011-06-26 03:37:18 +0200900 type = batadv_arp_get_type(bat_priv, skb, hdr_size);
901 if (type != ARPOP_REQUEST)
902 goto out;
903
904 hw_src = batadv_arp_hw_src(skb, hdr_size);
905 ip_src = batadv_arp_ip_src(skb, hdr_size);
906 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
907
908 batadv_dbg_arp(bat_priv, skb, type, hdr_size,
909 "Parsing incoming ARP REQUEST");
910
911 batadv_dat_entry_add(bat_priv, ip_src, hw_src);
912
913 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst);
914 if (!dat_entry)
915 goto out;
916
Antonio Quartullic384ea32011-06-26 03:37:18 +0200917 skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
Marek Lindner736292c2013-01-12 19:19:06 +0800918 bat_priv->soft_iface, ip_dst, hw_src,
Antonio Quartullic384ea32011-06-26 03:37:18 +0200919 dat_entry->mac_addr, hw_src);
920
921 if (!skb_new)
922 goto out;
923
Marek Lindner93178012013-03-10 19:29:15 +0800924 /* To preserve backwards compatibility, the node has choose the outgoing
925 * format based on the incoming request packet type. The assumption is
926 * that a node not using the 4addr packet format doesn't support it.
Antonio Quartullic384ea32011-06-26 03:37:18 +0200927 */
928 if (hdr_size == sizeof(struct batadv_unicast_4addr_packet))
929 err = batadv_unicast_4addr_send_skb(bat_priv, skb_new,
930 BATADV_P_DAT_CACHE_REPLY);
931 else
932 err = batadv_unicast_send_skb(bat_priv, skb_new);
933
Martin Hundebøll4046b242012-04-20 17:02:45 +0200934 if (!err) {
935 batadv_inc_counter(bat_priv, BATADV_CNT_DAT_CACHED_REPLY_TX);
Antonio Quartullic384ea32011-06-26 03:37:18 +0200936 ret = true;
Martin Hundebøll4046b242012-04-20 17:02:45 +0200937 }
Antonio Quartullic384ea32011-06-26 03:37:18 +0200938out:
939 if (dat_entry)
940 batadv_dat_entry_free_ref(dat_entry);
Antonio Quartullic384ea32011-06-26 03:37:18 +0200941 if (ret)
942 kfree_skb(skb);
943 return ret;
944}
945
946/**
947 * batadv_dat_snoop_outgoing_arp_reply - snoop the ARP reply and fill the DHT
948 * @bat_priv: the bat priv with all the soft interface information
949 * @skb: packet to check
950 */
951void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv,
952 struct sk_buff *skb)
953{
954 uint16_t type;
955 __be32 ip_src, ip_dst;
956 uint8_t *hw_src, *hw_dst;
957
Antonio Quartulli33af49a2012-08-08 18:50:57 +0200958 if (!atomic_read(&bat_priv->distributed_arp_table))
959 return;
960
Antonio Quartullic384ea32011-06-26 03:37:18 +0200961 type = batadv_arp_get_type(bat_priv, skb, 0);
962 if (type != ARPOP_REPLY)
963 return;
964
965 batadv_dbg_arp(bat_priv, skb, type, 0, "Parsing outgoing ARP REPLY");
966
967 hw_src = batadv_arp_hw_src(skb, 0);
968 ip_src = batadv_arp_ip_src(skb, 0);
969 hw_dst = batadv_arp_hw_dst(skb, 0);
970 ip_dst = batadv_arp_ip_dst(skb, 0);
971
972 batadv_dat_entry_add(bat_priv, ip_src, hw_src);
973 batadv_dat_entry_add(bat_priv, ip_dst, hw_dst);
974
975 /* Send the ARP reply to the candidates for both the IP addresses that
Marek Lindner93178012013-03-10 19:29:15 +0800976 * the node obtained from the ARP reply
Antonio Quartullic384ea32011-06-26 03:37:18 +0200977 */
978 batadv_dat_send_data(bat_priv, skb, ip_src, BATADV_P_DAT_DHT_PUT);
979 batadv_dat_send_data(bat_priv, skb, ip_dst, BATADV_P_DAT_DHT_PUT);
980}
981/**
982 * batadv_dat_snoop_incoming_arp_reply - snoop the ARP reply and fill the local
983 * DAT storage only
984 * @bat_priv: the bat priv with all the soft interface information
985 * @skb: packet to check
Marek Lindner93178012013-03-10 19:29:15 +0800986 * @hdr_size: size of the encapsulation header
Antonio Quartullic384ea32011-06-26 03:37:18 +0200987 */
988bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
989 struct sk_buff *skb, int hdr_size)
990{
991 uint16_t type;
992 __be32 ip_src, ip_dst;
993 uint8_t *hw_src, *hw_dst;
994 bool ret = false;
995
Antonio Quartulli33af49a2012-08-08 18:50:57 +0200996 if (!atomic_read(&bat_priv->distributed_arp_table))
997 goto out;
998
Antonio Quartullic384ea32011-06-26 03:37:18 +0200999 type = batadv_arp_get_type(bat_priv, skb, hdr_size);
1000 if (type != ARPOP_REPLY)
1001 goto out;
1002
1003 batadv_dbg_arp(bat_priv, skb, type, hdr_size,
1004 "Parsing incoming ARP REPLY");
1005
1006 hw_src = batadv_arp_hw_src(skb, hdr_size);
1007 ip_src = batadv_arp_ip_src(skb, hdr_size);
1008 hw_dst = batadv_arp_hw_dst(skb, hdr_size);
1009 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
1010
1011 /* Update our internal cache with both the IP addresses the node got
1012 * within the ARP reply
1013 */
1014 batadv_dat_entry_add(bat_priv, ip_src, hw_src);
1015 batadv_dat_entry_add(bat_priv, ip_dst, hw_dst);
1016
1017 /* if this REPLY is directed to a client of mine, let's deliver the
1018 * packet to the interface
1019 */
1020 ret = !batadv_is_my_client(bat_priv, hw_dst);
1021out:
Matthias Schiffer0d15bec2013-01-23 18:11:53 +01001022 if (ret)
1023 kfree_skb(skb);
Antonio Quartullic384ea32011-06-26 03:37:18 +02001024 /* if ret == false -> packet has to be delivered to the interface */
1025 return ret;
1026}
1027
1028/**
1029 * batadv_dat_drop_broadcast_packet - check if an ARP request has to be dropped
Marek Lindner93178012013-03-10 19:29:15 +08001030 * (because the node has already obtained the reply via DAT) or not
Antonio Quartullic384ea32011-06-26 03:37:18 +02001031 * @bat_priv: the bat priv with all the soft interface information
1032 * @forw_packet: the broadcast packet
1033 *
Marek Lindner93178012013-03-10 19:29:15 +08001034 * Returns true if the node can drop the packet, false otherwise.
Antonio Quartullic384ea32011-06-26 03:37:18 +02001035 */
1036bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv,
1037 struct batadv_forw_packet *forw_packet)
1038{
1039 uint16_t type;
1040 __be32 ip_dst;
1041 struct batadv_dat_entry *dat_entry = NULL;
1042 bool ret = false;
1043 const size_t bcast_len = sizeof(struct batadv_bcast_packet);
1044
Antonio Quartulli33af49a2012-08-08 18:50:57 +02001045 if (!atomic_read(&bat_priv->distributed_arp_table))
1046 goto out;
1047
Antonio Quartullic384ea32011-06-26 03:37:18 +02001048 /* If this packet is an ARP_REQUEST and the node already has the
1049 * information that it is going to ask, then the packet can be dropped
1050 */
1051 if (forw_packet->num_packets)
1052 goto out;
1053
1054 type = batadv_arp_get_type(bat_priv, forw_packet->skb, bcast_len);
1055 if (type != ARPOP_REQUEST)
1056 goto out;
1057
1058 ip_dst = batadv_arp_ip_dst(forw_packet->skb, bcast_len);
1059 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst);
1060 /* check if the node already got this entry */
1061 if (!dat_entry) {
1062 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1063 "ARP Request for %pI4: fallback\n", &ip_dst);
1064 goto out;
1065 }
1066
1067 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1068 "ARP Request for %pI4: fallback prevented\n", &ip_dst);
1069 ret = true;
1070
1071out:
1072 if (dat_entry)
1073 batadv_dat_entry_free_ref(dat_entry);
1074 return ret;
1075}