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0b873931 | 1 | /* Copyright (C) 2011-2013 B.A.T.M.A.N. contributors: |
785ea114 AQ |
2 | * |
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> | |
c384ea3e | 22 | #include <net/arp.h> |
785ea114 AQ |
23 | |
24 | #include "main.h" | |
5c3a0e55 | 25 | #include "hash.h" |
785ea114 AQ |
26 | #include "distributed-arp-table.h" |
27 | #include "hard-interface.h" | |
28 | #include "originator.h" | |
29 | #include "send.h" | |
30 | #include "types.h" | |
c384ea3e | 31 | #include "translation-table.h" |
785ea114 AQ |
32 | #include "unicast.h" |
33 | ||
2f1dfbe1 AQ |
34 | static 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 | */ | |
40 | static 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 | /** | |
48 | * batadv_dat_entry_free_ref - decrements the dat_entry refcounter and possibly | |
49 | * free it | |
50 | * @dat_entry: the oentry to free | |
51 | */ | |
52 | static 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 | /** | |
59 | * batadv_dat_to_purge - checks whether a dat_entry has to be purged or not | |
60 | * @dat_entry: the entry to check | |
61 | * | |
62 | * Returns true if the entry has to be purged now, false otherwise | |
63 | */ | |
64 | static 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 | * | |
78 | * Loops over each entry in the DAT local storage and delete it if and only if | |
79 | * the to_purge function passed as argument returns true | |
80 | */ | |
81 | static 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; | |
b67bfe0d | 86 | struct hlist_node *node_tmp; |
2f1dfbe1 AQ |
87 | 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); | |
b67bfe0d | 98 | hlist_for_each_entry_safe(dat_entry, node_tmp, head, |
2f1dfbe1 AQ |
99 | hash_entry) { |
100 | /* if an helper function has been passed as parameter, | |
101 | * ask it if the entry has to be purged or not | |
102 | */ | |
103 | if (to_purge && !to_purge(dat_entry)) | |
104 | continue; | |
105 | ||
b67bfe0d | 106 | hlist_del_rcu(&dat_entry->hash_entry); |
2f1dfbe1 AQ |
107 | 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 | */ | |
118 | static 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 | * | |
137 | * Returns 1 if the two entry are the same, 0 otherwise | |
138 | */ | |
139 | static 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 | ||
5c3a0e55 AQ |
147 | /** |
148 | * 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 | * | |
152 | * Returns the value of the hw_src field in the ARP packet | |
153 | */ | |
154 | static 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 | * | |
169 | * Returns the value of the ip_src field in the ARP packet | |
170 | */ | |
171 | static __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 | * | |
181 | * Returns the value of the hw_dst field in the ARP packet | |
182 | */ | |
183 | static 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 | * | |
193 | * Returns the value of the ip_dst field in the ARP packet | |
194 | */ | |
195 | static __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 | ||
785ea114 AQ |
200 | /** |
201 | * batadv_hash_dat - compute the hash value for an IP address | |
202 | * @data: data to hash | |
203 | * @size: size of the hash table | |
204 | * | |
205 | * Returns the selected index in the hash table for the given data | |
206 | */ | |
207 | static 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 | ||
2f1dfbe1 AQ |
226 | /** |
227 | * batadv_dat_entry_hash_find - looks for a given dat_entry in the local hash | |
228 | * table | |
229 | * @bat_priv: the bat priv with all the soft interface information | |
230 | * @ip: search key | |
231 | * | |
232 | * Returns the dat_entry if found, NULL otherwise | |
233 | */ | |
234 | static struct batadv_dat_entry * | |
235 | batadv_dat_entry_hash_find(struct batadv_priv *bat_priv, __be32 ip) | |
236 | { | |
237 | struct hlist_head *head; | |
2f1dfbe1 AQ |
238 | 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(); | |
b67bfe0d | 249 | hlist_for_each_entry_rcu(dat_entry, head, hash_entry) { |
2f1dfbe1 AQ |
250 | 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 | */ | |
270 | static 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 | ||
310 | out: | |
311 | if (dat_entry) | |
312 | batadv_dat_entry_free_ref(dat_entry); | |
313 | } | |
314 | ||
5c3a0e55 AQ |
315 | #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 | */ | |
325 | static 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 | ||
346 | /* if the ARP packet is encapsulated in a batman packet, let's print | |
347 | * some debug messages | |
348 | */ | |
349 | unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data; | |
350 | ||
351 | switch (unicast_4addr_packet->u.header.packet_type) { | |
352 | case BATADV_UNICAST: | |
353 | batadv_dbg(BATADV_DBG_DAT, bat_priv, | |
354 | "* encapsulated within a UNICAST packet\n"); | |
355 | break; | |
356 | case BATADV_UNICAST_4ADDR: | |
357 | batadv_dbg(BATADV_DBG_DAT, bat_priv, | |
358 | "* encapsulated within a UNICAST_4ADDR packet (src: %pM)\n", | |
359 | unicast_4addr_packet->src); | |
360 | switch (unicast_4addr_packet->subtype) { | |
361 | case BATADV_P_DAT_DHT_PUT: | |
362 | batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_PUT\n"); | |
363 | break; | |
364 | case BATADV_P_DAT_DHT_GET: | |
365 | batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_GET\n"); | |
366 | break; | |
367 | case BATADV_P_DAT_CACHE_REPLY: | |
368 | batadv_dbg(BATADV_DBG_DAT, bat_priv, | |
369 | "* type: DAT_CACHE_REPLY\n"); | |
370 | break; | |
371 | case BATADV_P_DATA: | |
372 | batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DATA\n"); | |
373 | break; | |
374 | default: | |
375 | batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: Unknown (%u)!\n", | |
376 | unicast_4addr_packet->u.header.packet_type); | |
377 | } | |
378 | break; | |
379 | case BATADV_BCAST: | |
380 | bcast_pkt = (struct batadv_bcast_packet *)unicast_4addr_packet; | |
381 | orig_addr = bcast_pkt->orig; | |
382 | batadv_dbg(BATADV_DBG_DAT, bat_priv, | |
383 | "* encapsulated within a BCAST packet (src: %pM)\n", | |
384 | orig_addr); | |
385 | break; | |
386 | default: | |
387 | batadv_dbg(BATADV_DBG_DAT, bat_priv, | |
388 | "* encapsulated within an unknown packet type (0x%x)\n", | |
389 | unicast_4addr_packet->u.header.packet_type); | |
390 | } | |
391 | } | |
392 | ||
393 | #else | |
394 | ||
395 | static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb, | |
396 | uint16_t type, int hdr_size, char *msg) | |
397 | { | |
398 | } | |
399 | ||
400 | #endif /* CONFIG_BATMAN_ADV_DEBUG */ | |
401 | ||
785ea114 AQ |
402 | /** |
403 | * batadv_is_orig_node_eligible - check whether a node can be a DHT candidate | |
404 | * @res: the array with the already selected candidates | |
405 | * @select: number of already selected candidates | |
406 | * @tmp_max: address of the currently evaluated node | |
407 | * @max: current round max address | |
408 | * @last_max: address of the last selected candidate | |
409 | * @candidate: orig_node under evaluation | |
410 | * @max_orig_node: last selected candidate | |
411 | * | |
412 | * Returns true if the node has been elected as next candidate or false othrwise | |
413 | */ | |
414 | static bool batadv_is_orig_node_eligible(struct batadv_dat_candidate *res, | |
415 | int select, batadv_dat_addr_t tmp_max, | |
416 | batadv_dat_addr_t max, | |
417 | batadv_dat_addr_t last_max, | |
418 | struct batadv_orig_node *candidate, | |
419 | struct batadv_orig_node *max_orig_node) | |
420 | { | |
421 | bool ret = false; | |
422 | int j; | |
423 | ||
424 | /* Check if this node has already been selected... */ | |
425 | for (j = 0; j < select; j++) | |
426 | if (res[j].orig_node == candidate) | |
427 | break; | |
428 | /* ..and possibly skip it */ | |
429 | if (j < select) | |
430 | goto out; | |
431 | /* sanity check: has it already been selected? This should not happen */ | |
432 | if (tmp_max > last_max) | |
433 | goto out; | |
434 | /* check if during this iteration an originator with a closer dht | |
435 | * address has already been found | |
436 | */ | |
437 | if (tmp_max < max) | |
438 | goto out; | |
439 | /* this is an hash collision with the temporary selected node. Choose | |
440 | * the one with the lowest address | |
441 | */ | |
816cd5b8 | 442 | if ((tmp_max == max) && max_orig_node && |
785ea114 AQ |
443 | (batadv_compare_eth(candidate->orig, max_orig_node->orig) > 0)) |
444 | goto out; | |
445 | ||
446 | ret = true; | |
447 | out: | |
448 | return ret; | |
449 | } | |
450 | ||
451 | /** | |
452 | * batadv_choose_next_candidate - select the next DHT candidate | |
453 | * @bat_priv: the bat priv with all the soft interface information | |
454 | * @cands: candidates array | |
455 | * @select: number of candidates already present in the array | |
456 | * @ip_key: key to look up in the DHT | |
457 | * @last_max: pointer where the address of the selected candidate will be saved | |
458 | */ | |
459 | static void batadv_choose_next_candidate(struct batadv_priv *bat_priv, | |
460 | struct batadv_dat_candidate *cands, | |
461 | int select, batadv_dat_addr_t ip_key, | |
462 | batadv_dat_addr_t *last_max) | |
463 | { | |
464 | batadv_dat_addr_t max = 0, tmp_max = 0; | |
465 | struct batadv_orig_node *orig_node, *max_orig_node = NULL; | |
466 | struct batadv_hashtable *hash = bat_priv->orig_hash; | |
785ea114 AQ |
467 | struct hlist_head *head; |
468 | int i; | |
469 | ||
470 | /* if no node is eligible as candidate, leave the candidate type as | |
471 | * NOT_FOUND | |
472 | */ | |
473 | cands[select].type = BATADV_DAT_CANDIDATE_NOT_FOUND; | |
474 | ||
475 | /* iterate over the originator list and find the node with closest | |
476 | * dat_address which has not been selected yet | |
477 | */ | |
478 | for (i = 0; i < hash->size; i++) { | |
479 | head = &hash->table[i]; | |
480 | ||
481 | rcu_read_lock(); | |
b67bfe0d | 482 | hlist_for_each_entry_rcu(orig_node, head, hash_entry) { |
785ea114 AQ |
483 | /* the dht space is a ring and addresses are unsigned */ |
484 | tmp_max = BATADV_DAT_ADDR_MAX - orig_node->dat_addr + | |
485 | ip_key; | |
486 | ||
487 | if (!batadv_is_orig_node_eligible(cands, select, | |
488 | tmp_max, max, | |
489 | *last_max, orig_node, | |
490 | max_orig_node)) | |
491 | continue; | |
492 | ||
493 | if (!atomic_inc_not_zero(&orig_node->refcount)) | |
494 | continue; | |
495 | ||
496 | max = tmp_max; | |
497 | if (max_orig_node) | |
498 | batadv_orig_node_free_ref(max_orig_node); | |
499 | max_orig_node = orig_node; | |
500 | } | |
501 | rcu_read_unlock(); | |
502 | } | |
503 | if (max_orig_node) { | |
504 | cands[select].type = BATADV_DAT_CANDIDATE_ORIG; | |
505 | cands[select].orig_node = max_orig_node; | |
506 | batadv_dbg(BATADV_DBG_DAT, bat_priv, | |
507 | "dat_select_candidates() %d: selected %pM addr=%u dist=%u\n", | |
508 | select, max_orig_node->orig, max_orig_node->dat_addr, | |
509 | max); | |
510 | } | |
511 | *last_max = max; | |
512 | } | |
513 | ||
514 | /** | |
515 | * batadv_dat_select_candidates - selects the nodes which the DHT message has to | |
516 | * be sent to | |
517 | * @bat_priv: the bat priv with all the soft interface information | |
518 | * @ip_dst: ipv4 to look up in the DHT | |
519 | * | |
520 | * An originator O is selected if and only if its DHT_ID value is one of three | |
521 | * closest values (from the LEFT, with wrap around if needed) then the hash | |
522 | * value of the key. ip_dst is the key. | |
523 | * | |
524 | * Returns the candidate array of size BATADV_DAT_CANDIDATE_NUM | |
525 | */ | |
526 | static struct batadv_dat_candidate * | |
527 | batadv_dat_select_candidates(struct batadv_priv *bat_priv, __be32 ip_dst) | |
528 | { | |
529 | int select; | |
530 | batadv_dat_addr_t last_max = BATADV_DAT_ADDR_MAX, ip_key; | |
531 | struct batadv_dat_candidate *res; | |
532 | ||
533 | if (!bat_priv->orig_hash) | |
534 | return NULL; | |
535 | ||
536 | res = kmalloc(BATADV_DAT_CANDIDATES_NUM * sizeof(*res), GFP_ATOMIC); | |
537 | if (!res) | |
538 | return NULL; | |
539 | ||
540 | ip_key = (batadv_dat_addr_t)batadv_hash_dat(&ip_dst, | |
541 | BATADV_DAT_ADDR_MAX); | |
542 | ||
543 | batadv_dbg(BATADV_DBG_DAT, bat_priv, | |
544 | "dat_select_candidates(): IP=%pI4 hash(IP)=%u\n", &ip_dst, | |
545 | ip_key); | |
546 | ||
547 | for (select = 0; select < BATADV_DAT_CANDIDATES_NUM; select++) | |
548 | batadv_choose_next_candidate(bat_priv, res, select, ip_key, | |
549 | &last_max); | |
550 | ||
551 | return res; | |
552 | } | |
553 | ||
554 | /** | |
555 | * batadv_dat_send_data - send a payload to the selected candidates | |
556 | * @bat_priv: the bat priv with all the soft interface information | |
557 | * @skb: payload to send | |
558 | * @ip: the DHT key | |
559 | * @packet_subtype: unicast4addr packet subtype to use | |
560 | * | |
561 | * In this function the skb is copied by means of pskb_copy() and is sent as | |
562 | * unicast packet to each of the selected candidates | |
563 | * | |
564 | * Returns true if the packet is sent to at least one candidate, false otherwise | |
565 | */ | |
566 | static bool batadv_dat_send_data(struct batadv_priv *bat_priv, | |
567 | struct sk_buff *skb, __be32 ip, | |
568 | int packet_subtype) | |
569 | { | |
570 | int i; | |
571 | bool ret = false; | |
572 | int send_status; | |
573 | struct batadv_neigh_node *neigh_node = NULL; | |
574 | struct sk_buff *tmp_skb; | |
575 | struct batadv_dat_candidate *cand; | |
576 | ||
577 | cand = batadv_dat_select_candidates(bat_priv, ip); | |
578 | if (!cand) | |
579 | goto out; | |
580 | ||
581 | batadv_dbg(BATADV_DBG_DAT, bat_priv, "DHT_SEND for %pI4\n", &ip); | |
582 | ||
583 | for (i = 0; i < BATADV_DAT_CANDIDATES_NUM; i++) { | |
584 | if (cand[i].type == BATADV_DAT_CANDIDATE_NOT_FOUND) | |
585 | continue; | |
586 | ||
587 | neigh_node = batadv_orig_node_get_router(cand[i].orig_node); | |
588 | if (!neigh_node) | |
589 | goto free_orig; | |
590 | ||
591 | tmp_skb = pskb_copy(skb, GFP_ATOMIC); | |
592 | if (!batadv_unicast_4addr_prepare_skb(bat_priv, tmp_skb, | |
593 | cand[i].orig_node, | |
594 | packet_subtype)) { | |
595 | kfree_skb(tmp_skb); | |
596 | goto free_neigh; | |
597 | } | |
598 | ||
599 | send_status = batadv_send_skb_packet(tmp_skb, | |
600 | neigh_node->if_incoming, | |
601 | neigh_node->addr); | |
4046b24a MH |
602 | if (send_status == NET_XMIT_SUCCESS) { |
603 | /* count the sent packet */ | |
604 | switch (packet_subtype) { | |
605 | case BATADV_P_DAT_DHT_GET: | |
606 | batadv_inc_counter(bat_priv, | |
607 | BATADV_CNT_DAT_GET_TX); | |
608 | break; | |
609 | case BATADV_P_DAT_DHT_PUT: | |
610 | batadv_inc_counter(bat_priv, | |
611 | BATADV_CNT_DAT_PUT_TX); | |
612 | break; | |
613 | } | |
614 | ||
785ea114 AQ |
615 | /* packet sent to a candidate: return true */ |
616 | ret = true; | |
4046b24a | 617 | } |
785ea114 AQ |
618 | free_neigh: |
619 | batadv_neigh_node_free_ref(neigh_node); | |
620 | free_orig: | |
621 | batadv_orig_node_free_ref(cand[i].orig_node); | |
622 | } | |
623 | ||
624 | out: | |
625 | kfree(cand); | |
626 | return ret; | |
627 | } | |
2f1dfbe1 AQ |
628 | |
629 | /** | |
630 | * batadv_dat_hash_free - free the local DAT hash table | |
631 | * @bat_priv: the bat priv with all the soft interface information | |
632 | */ | |
633 | static void batadv_dat_hash_free(struct batadv_priv *bat_priv) | |
634 | { | |
33af49ad AQ |
635 | if (!bat_priv->dat.hash) |
636 | return; | |
637 | ||
2f1dfbe1 AQ |
638 | __batadv_dat_purge(bat_priv, NULL); |
639 | ||
640 | batadv_hash_destroy(bat_priv->dat.hash); | |
641 | ||
642 | bat_priv->dat.hash = NULL; | |
643 | } | |
644 | ||
645 | /** | |
646 | * batadv_dat_init - initialise the DAT internals | |
647 | * @bat_priv: the bat priv with all the soft interface information | |
648 | */ | |
649 | int batadv_dat_init(struct batadv_priv *bat_priv) | |
650 | { | |
651 | if (bat_priv->dat.hash) | |
652 | return 0; | |
653 | ||
654 | bat_priv->dat.hash = batadv_hash_new(1024); | |
655 | ||
656 | if (!bat_priv->dat.hash) | |
657 | return -ENOMEM; | |
658 | ||
659 | batadv_dat_start_timer(bat_priv); | |
660 | ||
661 | return 0; | |
662 | } | |
663 | ||
664 | /** | |
665 | * batadv_dat_free - free the DAT internals | |
666 | * @bat_priv: the bat priv with all the soft interface information | |
667 | */ | |
668 | void batadv_dat_free(struct batadv_priv *bat_priv) | |
669 | { | |
670 | cancel_delayed_work_sync(&bat_priv->dat.work); | |
671 | ||
672 | batadv_dat_hash_free(bat_priv); | |
673 | } | |
674 | ||
675 | /** | |
676 | * batadv_dat_cache_seq_print_text - print the local DAT hash table | |
677 | * @seq: seq file to print on | |
678 | * @offset: not used | |
679 | */ | |
680 | int batadv_dat_cache_seq_print_text(struct seq_file *seq, void *offset) | |
681 | { | |
682 | struct net_device *net_dev = (struct net_device *)seq->private; | |
683 | struct batadv_priv *bat_priv = netdev_priv(net_dev); | |
684 | struct batadv_hashtable *hash = bat_priv->dat.hash; | |
685 | struct batadv_dat_entry *dat_entry; | |
686 | struct batadv_hard_iface *primary_if; | |
2f1dfbe1 AQ |
687 | struct hlist_head *head; |
688 | unsigned long last_seen_jiffies; | |
689 | int last_seen_msecs, last_seen_secs, last_seen_mins; | |
690 | uint32_t i; | |
691 | ||
692 | primary_if = batadv_seq_print_text_primary_if_get(seq); | |
693 | if (!primary_if) | |
694 | goto out; | |
695 | ||
696 | seq_printf(seq, "Distributed ARP Table (%s):\n", net_dev->name); | |
697 | seq_printf(seq, " %-7s %-13s %5s\n", "IPv4", "MAC", | |
698 | "last-seen"); | |
699 | ||
700 | for (i = 0; i < hash->size; i++) { | |
701 | head = &hash->table[i]; | |
702 | ||
703 | rcu_read_lock(); | |
b67bfe0d | 704 | hlist_for_each_entry_rcu(dat_entry, head, hash_entry) { |
2f1dfbe1 AQ |
705 | last_seen_jiffies = jiffies - dat_entry->last_update; |
706 | last_seen_msecs = jiffies_to_msecs(last_seen_jiffies); | |
707 | last_seen_mins = last_seen_msecs / 60000; | |
708 | last_seen_msecs = last_seen_msecs % 60000; | |
709 | last_seen_secs = last_seen_msecs / 1000; | |
710 | ||
711 | seq_printf(seq, " * %15pI4 %14pM %6i:%02i\n", | |
712 | &dat_entry->ip, dat_entry->mac_addr, | |
713 | last_seen_mins, last_seen_secs); | |
714 | } | |
715 | rcu_read_unlock(); | |
716 | } | |
717 | ||
718 | out: | |
719 | if (primary_if) | |
720 | batadv_hardif_free_ref(primary_if); | |
721 | return 0; | |
722 | } | |
5c3a0e55 AQ |
723 | |
724 | /** | |
725 | * batadv_arp_get_type - parse an ARP packet and gets the type | |
726 | * @bat_priv: the bat priv with all the soft interface information | |
727 | * @skb: packet to analyse | |
728 | * @hdr_size: size of the possible header before the ARP packet in the skb | |
729 | * | |
730 | * Returns the ARP type if the skb contains a valid ARP packet, 0 otherwise | |
731 | */ | |
732 | static uint16_t batadv_arp_get_type(struct batadv_priv *bat_priv, | |
733 | struct sk_buff *skb, int hdr_size) | |
734 | { | |
735 | struct arphdr *arphdr; | |
736 | struct ethhdr *ethhdr; | |
737 | __be32 ip_src, ip_dst; | |
b618ad11 | 738 | uint8_t *hw_src, *hw_dst; |
5c3a0e55 AQ |
739 | uint16_t type = 0; |
740 | ||
741 | /* pull the ethernet header */ | |
742 | if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN))) | |
743 | goto out; | |
744 | ||
745 | ethhdr = (struct ethhdr *)(skb->data + hdr_size); | |
746 | ||
747 | if (ethhdr->h_proto != htons(ETH_P_ARP)) | |
748 | goto out; | |
749 | ||
750 | /* pull the ARP payload */ | |
751 | if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN + | |
752 | arp_hdr_len(skb->dev)))) | |
753 | goto out; | |
754 | ||
755 | arphdr = (struct arphdr *)(skb->data + hdr_size + ETH_HLEN); | |
756 | ||
757 | /* Check whether the ARP packet carries a valid | |
758 | * IP information | |
759 | */ | |
760 | if (arphdr->ar_hrd != htons(ARPHRD_ETHER)) | |
761 | goto out; | |
762 | ||
763 | if (arphdr->ar_pro != htons(ETH_P_IP)) | |
764 | goto out; | |
765 | ||
766 | if (arphdr->ar_hln != ETH_ALEN) | |
767 | goto out; | |
768 | ||
769 | if (arphdr->ar_pln != 4) | |
770 | goto out; | |
771 | ||
772 | /* Check for bad reply/request. If the ARP message is not sane, DAT | |
773 | * will simply ignore it | |
774 | */ | |
775 | ip_src = batadv_arp_ip_src(skb, hdr_size); | |
776 | ip_dst = batadv_arp_ip_dst(skb, hdr_size); | |
777 | if (ipv4_is_loopback(ip_src) || ipv4_is_multicast(ip_src) || | |
757dd82e MS |
778 | ipv4_is_loopback(ip_dst) || ipv4_is_multicast(ip_dst) || |
779 | ipv4_is_zeronet(ip_src) || ipv4_is_lbcast(ip_src) || | |
780 | ipv4_is_zeronet(ip_dst) || ipv4_is_lbcast(ip_dst)) | |
5c3a0e55 AQ |
781 | goto out; |
782 | ||
b618ad11 MS |
783 | hw_src = batadv_arp_hw_src(skb, hdr_size); |
784 | if (is_zero_ether_addr(hw_src) || is_multicast_ether_addr(hw_src)) | |
785 | goto out; | |
786 | ||
787 | /* we don't care about the destination MAC address in ARP requests */ | |
788 | if (arphdr->ar_op != htons(ARPOP_REQUEST)) { | |
789 | hw_dst = batadv_arp_hw_dst(skb, hdr_size); | |
790 | if (is_zero_ether_addr(hw_dst) || | |
791 | is_multicast_ether_addr(hw_dst)) | |
792 | goto out; | |
793 | } | |
794 | ||
5c3a0e55 AQ |
795 | type = ntohs(arphdr->ar_op); |
796 | out: | |
797 | return type; | |
798 | } | |
c384ea3e AQ |
799 | |
800 | /** | |
801 | * batadv_dat_snoop_outgoing_arp_request - snoop the ARP request and try to | |
802 | * answer using DAT | |
803 | * @bat_priv: the bat priv with all the soft interface information | |
804 | * @skb: packet to check | |
805 | * | |
806 | * Returns true if the message has been sent to the dht candidates, false | |
807 | * otherwise. In case of true the message has to be enqueued to permit the | |
808 | * fallback | |
809 | */ | |
810 | bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv, | |
811 | struct sk_buff *skb) | |
812 | { | |
813 | uint16_t type = 0; | |
814 | __be32 ip_dst, ip_src; | |
815 | uint8_t *hw_src; | |
816 | bool ret = false; | |
817 | struct batadv_dat_entry *dat_entry = NULL; | |
818 | struct sk_buff *skb_new; | |
819 | struct batadv_hard_iface *primary_if = NULL; | |
820 | ||
33af49ad AQ |
821 | if (!atomic_read(&bat_priv->distributed_arp_table)) |
822 | goto out; | |
823 | ||
c384ea3e AQ |
824 | type = batadv_arp_get_type(bat_priv, skb, 0); |
825 | /* If the node gets an ARP_REQUEST it has to send a DHT_GET unicast | |
826 | * message to the selected DHT candidates | |
827 | */ | |
828 | if (type != ARPOP_REQUEST) | |
829 | goto out; | |
830 | ||
831 | batadv_dbg_arp(bat_priv, skb, type, 0, "Parsing outgoing ARP REQUEST"); | |
832 | ||
833 | ip_src = batadv_arp_ip_src(skb, 0); | |
834 | hw_src = batadv_arp_hw_src(skb, 0); | |
835 | ip_dst = batadv_arp_ip_dst(skb, 0); | |
836 | ||
837 | batadv_dat_entry_add(bat_priv, ip_src, hw_src); | |
838 | ||
839 | dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst); | |
840 | if (dat_entry) { | |
841 | primary_if = batadv_primary_if_get_selected(bat_priv); | |
842 | if (!primary_if) | |
843 | goto out; | |
844 | ||
845 | skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, | |
846 | primary_if->soft_iface, ip_dst, hw_src, | |
847 | dat_entry->mac_addr, hw_src); | |
848 | if (!skb_new) | |
849 | goto out; | |
850 | ||
851 | skb_reset_mac_header(skb_new); | |
852 | skb_new->protocol = eth_type_trans(skb_new, | |
853 | primary_if->soft_iface); | |
854 | bat_priv->stats.rx_packets++; | |
855 | bat_priv->stats.rx_bytes += skb->len + ETH_HLEN; | |
856 | primary_if->soft_iface->last_rx = jiffies; | |
857 | ||
858 | netif_rx(skb_new); | |
859 | batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP request replied locally\n"); | |
860 | ret = true; | |
861 | } else { | |
862 | /* Send the request on the DHT */ | |
863 | ret = batadv_dat_send_data(bat_priv, skb, ip_dst, | |
864 | BATADV_P_DAT_DHT_GET); | |
865 | } | |
866 | out: | |
867 | if (dat_entry) | |
868 | batadv_dat_entry_free_ref(dat_entry); | |
869 | if (primary_if) | |
870 | batadv_hardif_free_ref(primary_if); | |
871 | return ret; | |
872 | } | |
873 | ||
874 | /** | |
875 | * batadv_dat_snoop_incoming_arp_request - snoop the ARP request and try to | |
876 | * answer using the local DAT storage | |
877 | * @bat_priv: the bat priv with all the soft interface information | |
878 | * @skb: packet to check | |
879 | * @hdr_size: size of the encapsulation header | |
880 | * | |
881 | * Returns true if the request has been answered, false otherwise | |
882 | */ | |
883 | bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv, | |
884 | struct sk_buff *skb, int hdr_size) | |
885 | { | |
886 | uint16_t type; | |
887 | __be32 ip_src, ip_dst; | |
888 | uint8_t *hw_src; | |
889 | struct sk_buff *skb_new; | |
890 | struct batadv_hard_iface *primary_if = NULL; | |
891 | struct batadv_dat_entry *dat_entry = NULL; | |
892 | bool ret = false; | |
893 | int err; | |
894 | ||
33af49ad AQ |
895 | if (!atomic_read(&bat_priv->distributed_arp_table)) |
896 | goto out; | |
897 | ||
c384ea3e AQ |
898 | type = batadv_arp_get_type(bat_priv, skb, hdr_size); |
899 | if (type != ARPOP_REQUEST) | |
900 | goto out; | |
901 | ||
902 | hw_src = batadv_arp_hw_src(skb, hdr_size); | |
903 | ip_src = batadv_arp_ip_src(skb, hdr_size); | |
904 | ip_dst = batadv_arp_ip_dst(skb, hdr_size); | |
905 | ||
906 | batadv_dbg_arp(bat_priv, skb, type, hdr_size, | |
907 | "Parsing incoming ARP REQUEST"); | |
908 | ||
909 | batadv_dat_entry_add(bat_priv, ip_src, hw_src); | |
910 | ||
911 | dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst); | |
912 | if (!dat_entry) | |
913 | goto out; | |
914 | ||
915 | primary_if = batadv_primary_if_get_selected(bat_priv); | |
916 | if (!primary_if) | |
917 | goto out; | |
918 | ||
919 | skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, | |
920 | primary_if->soft_iface, ip_dst, hw_src, | |
921 | dat_entry->mac_addr, hw_src); | |
922 | ||
923 | if (!skb_new) | |
924 | goto out; | |
925 | ||
926 | /* to preserve backwards compatibility, here the node has to answer | |
927 | * using the same packet type it received for the request. This is due | |
928 | * to that if a node is not using the 4addr packet format it may not | |
929 | * support it. | |
930 | */ | |
931 | if (hdr_size == sizeof(struct batadv_unicast_4addr_packet)) | |
932 | err = batadv_unicast_4addr_send_skb(bat_priv, skb_new, | |
933 | BATADV_P_DAT_CACHE_REPLY); | |
934 | else | |
935 | err = batadv_unicast_send_skb(bat_priv, skb_new); | |
936 | ||
4046b24a MH |
937 | if (!err) { |
938 | batadv_inc_counter(bat_priv, BATADV_CNT_DAT_CACHED_REPLY_TX); | |
c384ea3e | 939 | ret = true; |
4046b24a | 940 | } |
c384ea3e AQ |
941 | out: |
942 | if (dat_entry) | |
943 | batadv_dat_entry_free_ref(dat_entry); | |
944 | if (primary_if) | |
945 | batadv_hardif_free_ref(primary_if); | |
946 | if (ret) | |
947 | kfree_skb(skb); | |
948 | return ret; | |
949 | } | |
950 | ||
951 | /** | |
952 | * batadv_dat_snoop_outgoing_arp_reply - snoop the ARP reply and fill the DHT | |
953 | * @bat_priv: the bat priv with all the soft interface information | |
954 | * @skb: packet to check | |
955 | */ | |
956 | void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv, | |
957 | struct sk_buff *skb) | |
958 | { | |
959 | uint16_t type; | |
960 | __be32 ip_src, ip_dst; | |
961 | uint8_t *hw_src, *hw_dst; | |
962 | ||
33af49ad AQ |
963 | if (!atomic_read(&bat_priv->distributed_arp_table)) |
964 | return; | |
965 | ||
c384ea3e AQ |
966 | type = batadv_arp_get_type(bat_priv, skb, 0); |
967 | if (type != ARPOP_REPLY) | |
968 | return; | |
969 | ||
970 | batadv_dbg_arp(bat_priv, skb, type, 0, "Parsing outgoing ARP REPLY"); | |
971 | ||
972 | hw_src = batadv_arp_hw_src(skb, 0); | |
973 | ip_src = batadv_arp_ip_src(skb, 0); | |
974 | hw_dst = batadv_arp_hw_dst(skb, 0); | |
975 | ip_dst = batadv_arp_ip_dst(skb, 0); | |
976 | ||
977 | batadv_dat_entry_add(bat_priv, ip_src, hw_src); | |
978 | batadv_dat_entry_add(bat_priv, ip_dst, hw_dst); | |
979 | ||
980 | /* Send the ARP reply to the candidates for both the IP addresses that | |
981 | * the node got within the ARP reply | |
982 | */ | |
983 | batadv_dat_send_data(bat_priv, skb, ip_src, BATADV_P_DAT_DHT_PUT); | |
984 | batadv_dat_send_data(bat_priv, skb, ip_dst, BATADV_P_DAT_DHT_PUT); | |
985 | } | |
986 | /** | |
987 | * batadv_dat_snoop_incoming_arp_reply - snoop the ARP reply and fill the local | |
988 | * DAT storage only | |
989 | * @bat_priv: the bat priv with all the soft interface information | |
990 | * @skb: packet to check | |
991 | * @hdr_size: siaze of the encapsulation header | |
992 | */ | |
993 | bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv, | |
994 | struct sk_buff *skb, int hdr_size) | |
995 | { | |
996 | uint16_t type; | |
997 | __be32 ip_src, ip_dst; | |
998 | uint8_t *hw_src, *hw_dst; | |
999 | bool ret = false; | |
1000 | ||
33af49ad AQ |
1001 | if (!atomic_read(&bat_priv->distributed_arp_table)) |
1002 | goto out; | |
1003 | ||
c384ea3e AQ |
1004 | type = batadv_arp_get_type(bat_priv, skb, hdr_size); |
1005 | if (type != ARPOP_REPLY) | |
1006 | goto out; | |
1007 | ||
1008 | batadv_dbg_arp(bat_priv, skb, type, hdr_size, | |
1009 | "Parsing incoming ARP REPLY"); | |
1010 | ||
1011 | hw_src = batadv_arp_hw_src(skb, hdr_size); | |
1012 | ip_src = batadv_arp_ip_src(skb, hdr_size); | |
1013 | hw_dst = batadv_arp_hw_dst(skb, hdr_size); | |
1014 | ip_dst = batadv_arp_ip_dst(skb, hdr_size); | |
1015 | ||
1016 | /* Update our internal cache with both the IP addresses the node got | |
1017 | * within the ARP reply | |
1018 | */ | |
1019 | batadv_dat_entry_add(bat_priv, ip_src, hw_src); | |
1020 | batadv_dat_entry_add(bat_priv, ip_dst, hw_dst); | |
1021 | ||
1022 | /* if this REPLY is directed to a client of mine, let's deliver the | |
1023 | * packet to the interface | |
1024 | */ | |
1025 | ret = !batadv_is_my_client(bat_priv, hw_dst); | |
1026 | out: | |
0d15bece MS |
1027 | if (ret) |
1028 | kfree_skb(skb); | |
c384ea3e AQ |
1029 | /* if ret == false -> packet has to be delivered to the interface */ |
1030 | return ret; | |
1031 | } | |
1032 | ||
1033 | /** | |
1034 | * batadv_dat_drop_broadcast_packet - check if an ARP request has to be dropped | |
1035 | * (because the node has already got the reply via DAT) or not | |
1036 | * @bat_priv: the bat priv with all the soft interface information | |
1037 | * @forw_packet: the broadcast packet | |
1038 | * | |
1039 | * Returns true if the node can drop the packet, false otherwise | |
1040 | */ | |
1041 | bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv, | |
1042 | struct batadv_forw_packet *forw_packet) | |
1043 | { | |
1044 | uint16_t type; | |
1045 | __be32 ip_dst; | |
1046 | struct batadv_dat_entry *dat_entry = NULL; | |
1047 | bool ret = false; | |
1048 | const size_t bcast_len = sizeof(struct batadv_bcast_packet); | |
1049 | ||
33af49ad AQ |
1050 | if (!atomic_read(&bat_priv->distributed_arp_table)) |
1051 | goto out; | |
1052 | ||
c384ea3e AQ |
1053 | /* If this packet is an ARP_REQUEST and the node already has the |
1054 | * information that it is going to ask, then the packet can be dropped | |
1055 | */ | |
1056 | if (forw_packet->num_packets) | |
1057 | goto out; | |
1058 | ||
1059 | type = batadv_arp_get_type(bat_priv, forw_packet->skb, bcast_len); | |
1060 | if (type != ARPOP_REQUEST) | |
1061 | goto out; | |
1062 | ||
1063 | ip_dst = batadv_arp_ip_dst(forw_packet->skb, bcast_len); | |
1064 | dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst); | |
1065 | /* check if the node already got this entry */ | |
1066 | if (!dat_entry) { | |
1067 | batadv_dbg(BATADV_DBG_DAT, bat_priv, | |
1068 | "ARP Request for %pI4: fallback\n", &ip_dst); | |
1069 | goto out; | |
1070 | } | |
1071 | ||
1072 | batadv_dbg(BATADV_DBG_DAT, bat_priv, | |
1073 | "ARP Request for %pI4: fallback prevented\n", &ip_dst); | |
1074 | ret = true; | |
1075 | ||
1076 | out: | |
1077 | if (dat_entry) | |
1078 | batadv_dat_entry_free_ref(dat_entry); | |
1079 | return ret; | |
1080 | } |