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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 | /** | |
93178018 | 48 | * batadv_dat_entry_free_ref - decrement the dat_entry refcounter and possibly |
2f1dfbe1 | 49 | * free it |
93178018 | 50 | * @dat_entry: the entry to free |
2f1dfbe1 AQ |
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 | /** | |
93178018 | 59 | * batadv_dat_to_purge - check whether a dat_entry has to be purged or not |
2f1dfbe1 AQ |
60 | * @dat_entry: the entry to check |
61 | * | |
93178018 | 62 | * Returns true if the entry has to be purged now, false otherwise. |
2f1dfbe1 AQ |
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 | * | |
93178018 ML |
78 | * 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. | |
2f1dfbe1 AQ |
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 | 99 | hash_entry) { |
93178018 | 100 | /* if a helper function has been passed as parameter, |
2f1dfbe1 AQ |
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 | * | |
93178018 | 137 | * Returns 1 if the two entries are the same, 0 otherwise. |
2f1dfbe1 AQ |
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 | * | |
93178018 | 152 | * Returns the value of the hw_src field in the ARP packet. |
5c3a0e55 AQ |
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 | * | |
93178018 | 169 | * Returns the value of the ip_src field in the ARP packet. |
5c3a0e55 AQ |
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 | * | |
93178018 | 181 | * Returns the value of the hw_dst field in the ARP packet. |
5c3a0e55 AQ |
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 | * | |
93178018 | 193 | * Returns the value of the ip_dst field in the ARP packet. |
5c3a0e55 AQ |
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 | * | |
93178018 | 205 | * Returns the selected index in the hash table for the given data. |
785ea114 AQ |
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 | 226 | /** |
93178018 | 227 | * batadv_dat_entry_hash_find - look for a given dat_entry in the local hash |
2f1dfbe1 AQ |
228 | * table |
229 | * @bat_priv: the bat priv with all the soft interface information | |
230 | * @ip: search key | |
231 | * | |
93178018 | 232 | * Returns the dat_entry if found, NULL otherwise. |
2f1dfbe1 AQ |
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 | ||
5c3a0e55 AQ |
346 | 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 | ||
392 | static 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 | ||
785ea114 AQ |
399 | /** |
400 | * 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 | * | |
93178018 ML |
409 | * Returns true if the node has been elected as next candidate or false |
410 | * otherwise. | |
785ea114 AQ |
411 | */ |
412 | static 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 | */ | |
816cd5b8 | 440 | if ((tmp_max == max) && max_orig_node && |
785ea114 AQ |
441 | (batadv_compare_eth(candidate->orig, max_orig_node->orig) > 0)) |
442 | goto out; | |
443 | ||
444 | ret = true; | |
445 | out: | |
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 | */ | |
457 | static 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; | |
785ea114 AQ |
465 | 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 | ||
93178018 | 473 | /* iterate over the originator list and find the node with the closest |
785ea114 AQ |
474 | * 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(); | |
b67bfe0d | 480 | hlist_for_each_entry_rcu(orig_node, head, hash_entry) { |
93178018 | 481 | /* the dht space is a ring using unsigned addresses */ |
785ea114 AQ |
482 | 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 | /** | |
93178018 | 513 | * batadv_dat_select_candidates - select the nodes which the DHT message has to |
785ea114 AQ |
514 | * 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 | * | |
93178018 | 522 | * Returns the candidate array of size BATADV_DAT_CANDIDATE_NUM. |
785ea114 AQ |
523 | */ |
524 | static struct batadv_dat_candidate * | |
525 | batadv_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 | * | |
93178018 ML |
559 | * This function copies the skb with pskb_copy() and is sent as unicast packet |
560 | * to each of the selected candidates. | |
785ea114 | 561 | * |
93178018 ML |
562 | * Returns true if the packet is sent to at least one candidate, false |
563 | * otherwise. | |
785ea114 AQ |
564 | */ |
565 | static 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); | |
4046b24a MH |
601 | 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 | ||
785ea114 AQ |
614 | /* packet sent to a candidate: return true */ |
615 | ret = true; | |
4046b24a | 616 | } |
785ea114 AQ |
617 | free_neigh: |
618 | batadv_neigh_node_free_ref(neigh_node); | |
619 | free_orig: | |
620 | batadv_orig_node_free_ref(cand[i].orig_node); | |
621 | } | |
622 | ||
623 | out: | |
624 | kfree(cand); | |
625 | return ret; | |
626 | } | |
2f1dfbe1 AQ |
627 | |
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 | */ | |
632 | static void batadv_dat_hash_free(struct batadv_priv *bat_priv) | |
633 | { | |
33af49ad AQ |
634 | if (!bat_priv->dat.hash) |
635 | return; | |
636 | ||
2f1dfbe1 AQ |
637 | __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 | */ | |
648 | int 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 | */ | |
667 | void 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 | */ | |
679 | int 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; | |
2f1dfbe1 AQ |
686 | 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(); | |
b67bfe0d | 703 | hlist_for_each_entry_rcu(dat_entry, head, hash_entry) { |
2f1dfbe1 AQ |
704 | 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 | ||
717 | out: | |
718 | if (primary_if) | |
719 | batadv_hardif_free_ref(primary_if); | |
720 | return 0; | |
721 | } | |
5c3a0e55 AQ |
722 | |
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 | * | |
93178018 | 729 | * Returns the ARP type if the skb contains a valid ARP packet, 0 otherwise. |
5c3a0e55 AQ |
730 | */ |
731 | static 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; | |
b618ad11 | 737 | uint8_t *hw_src, *hw_dst; |
5c3a0e55 AQ |
738 | 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 | ||
93178018 | 756 | /* check whether the ARP packet carries a valid IP information */ |
5c3a0e55 AQ |
757 | 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) || | |
757dd82e MS |
775 | 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)) | |
5c3a0e55 AQ |
778 | goto out; |
779 | ||
b618ad11 MS |
780 | 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 | ||
93178018 | 784 | /* don't care about the destination MAC address in ARP requests */ |
b618ad11 MS |
785 | 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 | ||
5c3a0e55 AQ |
792 | type = ntohs(arphdr->ar_op); |
793 | out: | |
794 | return type; | |
795 | } | |
c384ea3e AQ |
796 | |
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 | |
93178018 ML |
804 | * otherwise. In case of a positive return value the message has to be enqueued |
805 | * to permit the fallback. | |
c384ea3e AQ |
806 | */ |
807 | bool 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; | |
c384ea3e | 816 | |
33af49ad AQ |
817 | if (!atomic_read(&bat_priv->distributed_arp_table)) |
818 | goto out; | |
819 | ||
c384ea3e AQ |
820 | 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) { | |
88e48d7b AQ |
837 | /* 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 | ||
c384ea3e | 850 | skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, |
736292c2 | 851 | bat_priv->soft_iface, ip_dst, hw_src, |
c384ea3e AQ |
852 | 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, | |
736292c2 | 858 | bat_priv->soft_iface); |
c384ea3e AQ |
859 | bat_priv->stats.rx_packets++; |
860 | bat_priv->stats.rx_bytes += skb->len + ETH_HLEN; | |
736292c2 | 861 | bat_priv->soft_iface->last_rx = jiffies; |
c384ea3e AQ |
862 | |
863 | netif_rx(skb_new); | |
864 | batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP request replied locally\n"); | |
865 | ret = true; | |
866 | } else { | |
93178018 | 867 | /* Send the request to the DHT */ |
c384ea3e AQ |
868 | ret = batadv_dat_send_data(bat_priv, skb, ip_dst, |
869 | BATADV_P_DAT_DHT_GET); | |
870 | } | |
871 | out: | |
872 | if (dat_entry) | |
873 | batadv_dat_entry_free_ref(dat_entry); | |
c384ea3e AQ |
874 | 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 | * | |
93178018 | 884 | * Returns true if the request has been answered, false otherwise. |
c384ea3e AQ |
885 | */ |
886 | bool 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; | |
c384ea3e AQ |
893 | struct batadv_dat_entry *dat_entry = NULL; |
894 | bool ret = false; | |
895 | int err; | |
896 | ||
33af49ad AQ |
897 | if (!atomic_read(&bat_priv->distributed_arp_table)) |
898 | goto out; | |
899 | ||
c384ea3e AQ |
900 | 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 | ||
c384ea3e | 917 | skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src, |
736292c2 | 918 | bat_priv->soft_iface, ip_dst, hw_src, |
c384ea3e AQ |
919 | dat_entry->mac_addr, hw_src); |
920 | ||
921 | if (!skb_new) | |
922 | goto out; | |
923 | ||
93178018 ML |
924 | /* 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. | |
c384ea3e AQ |
927 | */ |
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 | ||
4046b24a MH |
934 | if (!err) { |
935 | batadv_inc_counter(bat_priv, BATADV_CNT_DAT_CACHED_REPLY_TX); | |
c384ea3e | 936 | ret = true; |
4046b24a | 937 | } |
c384ea3e AQ |
938 | out: |
939 | if (dat_entry) | |
940 | batadv_dat_entry_free_ref(dat_entry); | |
c384ea3e AQ |
941 | 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 | */ | |
951 | void 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 | ||
33af49ad AQ |
958 | if (!atomic_read(&bat_priv->distributed_arp_table)) |
959 | return; | |
960 | ||
c384ea3e AQ |
961 | 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 | |
93178018 | 976 | * the node obtained from the ARP reply |
c384ea3e AQ |
977 | */ |
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 | |
93178018 | 986 | * @hdr_size: size of the encapsulation header |
c384ea3e AQ |
987 | */ |
988 | bool 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 | ||
33af49ad AQ |
996 | if (!atomic_read(&bat_priv->distributed_arp_table)) |
997 | goto out; | |
998 | ||
c384ea3e AQ |
999 | 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); | |
1021 | out: | |
0d15bece MS |
1022 | if (ret) |
1023 | kfree_skb(skb); | |
c384ea3e AQ |
1024 | /* 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 | |
93178018 | 1030 | * (because the node has already obtained the reply via DAT) or not |
c384ea3e AQ |
1031 | * @bat_priv: the bat priv with all the soft interface information |
1032 | * @forw_packet: the broadcast packet | |
1033 | * | |
93178018 | 1034 | * Returns true if the node can drop the packet, false otherwise. |
c384ea3e AQ |
1035 | */ |
1036 | bool 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 | ||
33af49ad AQ |
1045 | if (!atomic_read(&bat_priv->distributed_arp_table)) |
1046 | goto out; | |
1047 | ||
c384ea3e AQ |
1048 | /* 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 | ||
1071 | out: | |
1072 | if (dat_entry) | |
1073 | batadv_dat_entry_free_ref(dat_entry); | |
1074 | return ret; | |
1075 | } |