1 /* Copyright (C) 2011-2013 B.A.T.M.A.N. contributors:
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.
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.
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
20 #include <linux/if_ether.h>
21 #include <linux/if_arp.h>
26 #include "distributed-arp-table.h"
27 #include "hard-interface.h"
28 #include "originator.h"
31 #include "translation-table.h"
33 static void batadv_dat_purge(struct work_struct *work);
36 * batadv_dat_start_timer - initialise the DAT periodic worker
37 * @bat_priv: the bat priv with all the soft interface information
39 static void batadv_dat_start_timer(struct batadv_priv *bat_priv)
41 INIT_DELAYED_WORK(&bat_priv->dat.work, batadv_dat_purge);
42 queue_delayed_work(batadv_event_workqueue, &bat_priv->dat.work,
43 msecs_to_jiffies(10000));
47 * batadv_dat_entry_free_ref - decrement the dat_entry refcounter and possibly
49 * @dat_entry: the entry to free
51 static void batadv_dat_entry_free_ref(struct batadv_dat_entry *dat_entry)
53 if (atomic_dec_and_test(&dat_entry->refcount))
54 kfree_rcu(dat_entry, rcu);
58 * batadv_dat_to_purge - check whether a dat_entry has to be purged or not
59 * @dat_entry: the entry to check
61 * Returns true if the entry has to be purged now, false otherwise.
63 static bool batadv_dat_to_purge(struct batadv_dat_entry *dat_entry)
65 return batadv_has_timed_out(dat_entry->last_update,
66 BATADV_DAT_ENTRY_TIMEOUT);
70 * __batadv_dat_purge - delete entries from the DAT local storage
71 * @bat_priv: the bat priv with all the soft interface information
72 * @to_purge: function in charge to decide whether an entry has to be purged or
73 * not. This function takes the dat_entry as argument and has to
74 * returns a boolean value: true is the entry has to be deleted,
77 * Loops over each entry in the DAT local storage and deletes it if and only if
78 * the to_purge function passed as argument returns true.
80 static void __batadv_dat_purge(struct batadv_priv *bat_priv,
81 bool (*to_purge)(struct batadv_dat_entry *))
83 spinlock_t *list_lock; /* protects write access to the hash lists */
84 struct batadv_dat_entry *dat_entry;
85 struct hlist_node *node_tmp;
86 struct hlist_head *head;
89 if (!bat_priv->dat.hash)
92 for (i = 0; i < bat_priv->dat.hash->size; i++) {
93 head = &bat_priv->dat.hash->table[i];
94 list_lock = &bat_priv->dat.hash->list_locks[i];
96 spin_lock_bh(list_lock);
97 hlist_for_each_entry_safe(dat_entry, node_tmp, head,
99 /* if a helper function has been passed as parameter,
100 * ask it if the entry has to be purged or not
102 if (to_purge && !to_purge(dat_entry))
105 hlist_del_rcu(&dat_entry->hash_entry);
106 batadv_dat_entry_free_ref(dat_entry);
108 spin_unlock_bh(list_lock);
113 * batadv_dat_purge - periodic task that deletes old entries from the local DAT
115 * @work: kernel work struct
117 static void batadv_dat_purge(struct work_struct *work)
119 struct delayed_work *delayed_work;
120 struct batadv_priv_dat *priv_dat;
121 struct batadv_priv *bat_priv;
123 delayed_work = container_of(work, struct delayed_work, work);
124 priv_dat = container_of(delayed_work, struct batadv_priv_dat, work);
125 bat_priv = container_of(priv_dat, struct batadv_priv, dat);
127 __batadv_dat_purge(bat_priv, batadv_dat_to_purge);
128 batadv_dat_start_timer(bat_priv);
132 * batadv_compare_dat - comparing function used in the local DAT hash table
133 * @node: node in the local table
134 * @data2: second object to compare the node to
136 * Returns 1 if the two entries are the same, 0 otherwise.
138 static int batadv_compare_dat(const struct hlist_node *node, const void *data2)
140 const void *data1 = container_of(node, struct batadv_dat_entry,
143 return (memcmp(data1, data2, sizeof(__be32)) == 0 ? 1 : 0);
147 * batadv_arp_hw_src - extract the hw_src field from an ARP packet
149 * @hdr_size: size of the possible header before the ARP packet
151 * Returns the value of the hw_src field in the ARP packet.
153 static uint8_t *batadv_arp_hw_src(struct sk_buff *skb, int hdr_size)
157 addr = (uint8_t *)(skb->data + hdr_size);
158 addr += ETH_HLEN + sizeof(struct arphdr);
164 * batadv_arp_ip_src - extract the ip_src field from an ARP packet
166 * @hdr_size: size of the possible header before the ARP packet
168 * Returns the value of the ip_src field in the ARP packet.
170 static __be32 batadv_arp_ip_src(struct sk_buff *skb, int hdr_size)
172 return *(__be32 *)(batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN);
176 * batadv_arp_hw_dst - extract the hw_dst field from an ARP packet
178 * @hdr_size: size of the possible header before the ARP packet
180 * Returns the value of the hw_dst field in the ARP packet.
182 static uint8_t *batadv_arp_hw_dst(struct sk_buff *skb, int hdr_size)
184 return batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN + 4;
188 * batadv_arp_ip_dst - extract the ip_dst field from an ARP packet
190 * @hdr_size: size of the possible header before the ARP packet
192 * Returns the value of the ip_dst field in the ARP packet.
194 static __be32 batadv_arp_ip_dst(struct sk_buff *skb, int hdr_size)
196 return *(__be32 *)(batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN * 2 + 4);
200 * batadv_hash_dat - compute the hash value for an IP address
201 * @data: data to hash
202 * @size: size of the hash table
204 * Returns the selected index in the hash table for the given data.
206 static uint32_t batadv_hash_dat(const void *data, uint32_t size)
208 const unsigned char *key = data;
212 for (i = 0; i < 4; i++) {
214 hash += (hash << 10);
219 hash ^= (hash >> 11);
220 hash += (hash << 15);
226 * batadv_dat_entry_hash_find - look for a given dat_entry in the local hash
228 * @bat_priv: the bat priv with all the soft interface information
231 * Returns the dat_entry if found, NULL otherwise.
233 static struct batadv_dat_entry *
234 batadv_dat_entry_hash_find(struct batadv_priv *bat_priv, __be32 ip)
236 struct hlist_head *head;
237 struct batadv_dat_entry *dat_entry, *dat_entry_tmp = NULL;
238 struct batadv_hashtable *hash = bat_priv->dat.hash;
244 index = batadv_hash_dat(&ip, hash->size);
245 head = &hash->table[index];
248 hlist_for_each_entry_rcu(dat_entry, head, hash_entry) {
249 if (dat_entry->ip != ip)
252 if (!atomic_inc_not_zero(&dat_entry->refcount))
255 dat_entry_tmp = dat_entry;
260 return dat_entry_tmp;
264 * batadv_dat_entry_add - add a new dat entry or update it if already exists
265 * @bat_priv: the bat priv with all the soft interface information
266 * @ip: ipv4 to add/edit
267 * @mac_addr: mac address to assign to the given ipv4
269 static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip,
272 struct batadv_dat_entry *dat_entry;
275 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip);
276 /* if this entry is already known, just update it */
278 if (!batadv_compare_eth(dat_entry->mac_addr, mac_addr))
279 memcpy(dat_entry->mac_addr, mac_addr, ETH_ALEN);
280 dat_entry->last_update = jiffies;
281 batadv_dbg(BATADV_DBG_DAT, bat_priv,
282 "Entry updated: %pI4 %pM\n", &dat_entry->ip,
283 dat_entry->mac_addr);
287 dat_entry = kmalloc(sizeof(*dat_entry), GFP_ATOMIC);
292 memcpy(dat_entry->mac_addr, mac_addr, ETH_ALEN);
293 dat_entry->last_update = jiffies;
294 atomic_set(&dat_entry->refcount, 2);
296 hash_added = batadv_hash_add(bat_priv->dat.hash, batadv_compare_dat,
297 batadv_hash_dat, &dat_entry->ip,
298 &dat_entry->hash_entry);
300 if (unlikely(hash_added != 0)) {
301 /* remove the reference for the hash */
302 batadv_dat_entry_free_ref(dat_entry);
306 batadv_dbg(BATADV_DBG_DAT, bat_priv, "New entry added: %pI4 %pM\n",
307 &dat_entry->ip, dat_entry->mac_addr);
311 batadv_dat_entry_free_ref(dat_entry);
314 #ifdef CONFIG_BATMAN_ADV_DEBUG
317 * batadv_dbg_arp - print a debug message containing all the ARP packet details
318 * @bat_priv: the bat priv with all the soft interface information
321 * @hdr_size: size of the possible header before the ARP packet
322 * @msg: message to print together with the debugging information
324 static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb,
325 uint16_t type, int hdr_size, char *msg)
327 struct batadv_unicast_4addr_packet *unicast_4addr_packet;
328 struct batadv_bcast_packet *bcast_pkt;
330 __be32 ip_src, ip_dst;
333 batadv_dbg(BATADV_DBG_DAT, bat_priv, "%s\n", msg);
335 ip_src = batadv_arp_ip_src(skb, hdr_size);
336 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
337 batadv_dbg(BATADV_DBG_DAT, bat_priv,
338 "ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]\n",
339 batadv_arp_hw_src(skb, hdr_size), &ip_src,
340 batadv_arp_hw_dst(skb, hdr_size), &ip_dst);
345 unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
347 switch (unicast_4addr_packet->u.header.packet_type) {
349 batadv_dbg(BATADV_DBG_DAT, bat_priv,
350 "* encapsulated within a UNICAST packet\n");
352 case BATADV_UNICAST_4ADDR:
353 batadv_dbg(BATADV_DBG_DAT, bat_priv,
354 "* encapsulated within a UNICAST_4ADDR packet (src: %pM)\n",
355 unicast_4addr_packet->src);
356 switch (unicast_4addr_packet->subtype) {
357 case BATADV_P_DAT_DHT_PUT:
358 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_PUT\n");
360 case BATADV_P_DAT_DHT_GET:
361 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_GET\n");
363 case BATADV_P_DAT_CACHE_REPLY:
364 batadv_dbg(BATADV_DBG_DAT, bat_priv,
365 "* type: DAT_CACHE_REPLY\n");
368 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DATA\n");
371 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: Unknown (%u)!\n",
372 unicast_4addr_packet->u.header.packet_type);
376 bcast_pkt = (struct batadv_bcast_packet *)unicast_4addr_packet;
377 orig_addr = bcast_pkt->orig;
378 batadv_dbg(BATADV_DBG_DAT, bat_priv,
379 "* encapsulated within a BCAST packet (src: %pM)\n",
383 batadv_dbg(BATADV_DBG_DAT, bat_priv,
384 "* encapsulated within an unknown packet type (0x%x)\n",
385 unicast_4addr_packet->u.header.packet_type);
391 static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb,
392 uint16_t type, int hdr_size, char *msg)
396 #endif /* CONFIG_BATMAN_ADV_DEBUG */
399 * batadv_is_orig_node_eligible - check whether a node can be a DHT candidate
400 * @res: the array with the already selected candidates
401 * @select: number of already selected candidates
402 * @tmp_max: address of the currently evaluated node
403 * @max: current round max address
404 * @last_max: address of the last selected candidate
405 * @candidate: orig_node under evaluation
406 * @max_orig_node: last selected candidate
408 * Returns true if the node has been elected as next candidate or false
411 static bool batadv_is_orig_node_eligible(struct batadv_dat_candidate *res,
412 int select, batadv_dat_addr_t tmp_max,
413 batadv_dat_addr_t max,
414 batadv_dat_addr_t last_max,
415 struct batadv_orig_node *candidate,
416 struct batadv_orig_node *max_orig_node)
421 /* check if orig node candidate is running DAT */
422 if (!(candidate->capabilities & BATADV_ORIG_CAPA_HAS_DAT))
425 /* Check if this node has already been selected... */
426 for (j = 0; j < select; j++)
427 if (res[j].orig_node == candidate)
429 /* ..and possibly skip it */
432 /* sanity check: has it already been selected? This should not happen */
433 if (tmp_max > last_max)
435 /* check if during this iteration an originator with a closer dht
436 * address has already been found
440 /* this is an hash collision with the temporary selected node. Choose
441 * the one with the lowest address
443 if ((tmp_max == max) && max_orig_node &&
444 (batadv_compare_eth(candidate->orig, max_orig_node->orig) > 0))
453 * batadv_choose_next_candidate - select the next DHT candidate
454 * @bat_priv: the bat priv with all the soft interface information
455 * @cands: candidates array
456 * @select: number of candidates already present in the array
457 * @ip_key: key to look up in the DHT
458 * @last_max: pointer where the address of the selected candidate will be saved
460 static void batadv_choose_next_candidate(struct batadv_priv *bat_priv,
461 struct batadv_dat_candidate *cands,
462 int select, batadv_dat_addr_t ip_key,
463 batadv_dat_addr_t *last_max)
465 batadv_dat_addr_t max = 0, tmp_max = 0;
466 struct batadv_orig_node *orig_node, *max_orig_node = NULL;
467 struct batadv_hashtable *hash = bat_priv->orig_hash;
468 struct hlist_head *head;
471 /* if no node is eligible as candidate, leave the candidate type as
474 cands[select].type = BATADV_DAT_CANDIDATE_NOT_FOUND;
476 /* iterate over the originator list and find the node with the closest
477 * dat_address which has not been selected yet
479 for (i = 0; i < hash->size; i++) {
480 head = &hash->table[i];
483 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
484 /* the dht space is a ring using unsigned addresses */
485 tmp_max = BATADV_DAT_ADDR_MAX - orig_node->dat_addr +
488 if (!batadv_is_orig_node_eligible(cands, select,
490 *last_max, orig_node,
494 if (!atomic_inc_not_zero(&orig_node->refcount))
499 batadv_orig_node_free_ref(max_orig_node);
500 max_orig_node = orig_node;
505 cands[select].type = BATADV_DAT_CANDIDATE_ORIG;
506 cands[select].orig_node = max_orig_node;
507 batadv_dbg(BATADV_DBG_DAT, bat_priv,
508 "dat_select_candidates() %d: selected %pM addr=%u dist=%u\n",
509 select, max_orig_node->orig, max_orig_node->dat_addr,
516 * batadv_dat_select_candidates - select the nodes which the DHT message has to
518 * @bat_priv: the bat priv with all the soft interface information
519 * @ip_dst: ipv4 to look up in the DHT
521 * An originator O is selected if and only if its DHT_ID value is one of three
522 * closest values (from the LEFT, with wrap around if needed) then the hash
523 * value of the key. ip_dst is the key.
525 * Returns the candidate array of size BATADV_DAT_CANDIDATE_NUM.
527 static struct batadv_dat_candidate *
528 batadv_dat_select_candidates(struct batadv_priv *bat_priv, __be32 ip_dst)
531 batadv_dat_addr_t last_max = BATADV_DAT_ADDR_MAX, ip_key;
532 struct batadv_dat_candidate *res;
534 if (!bat_priv->orig_hash)
537 res = kmalloc(BATADV_DAT_CANDIDATES_NUM * sizeof(*res), GFP_ATOMIC);
541 ip_key = (batadv_dat_addr_t)batadv_hash_dat(&ip_dst,
542 BATADV_DAT_ADDR_MAX);
544 batadv_dbg(BATADV_DBG_DAT, bat_priv,
545 "dat_select_candidates(): IP=%pI4 hash(IP)=%u\n", &ip_dst,
548 for (select = 0; select < BATADV_DAT_CANDIDATES_NUM; select++)
549 batadv_choose_next_candidate(bat_priv, res, select, ip_key,
556 * batadv_dat_send_data - send a payload to the selected candidates
557 * @bat_priv: the bat priv with all the soft interface information
558 * @skb: payload to send
560 * @packet_subtype: unicast4addr packet subtype to use
562 * This function copies the skb with pskb_copy() and is sent as unicast packet
563 * to each of the selected candidates.
565 * Returns true if the packet is sent to at least one candidate, false
568 static bool batadv_dat_send_data(struct batadv_priv *bat_priv,
569 struct sk_buff *skb, __be32 ip,
575 struct batadv_neigh_node *neigh_node = NULL;
576 struct sk_buff *tmp_skb;
577 struct batadv_dat_candidate *cand;
579 cand = batadv_dat_select_candidates(bat_priv, ip);
583 batadv_dbg(BATADV_DBG_DAT, bat_priv, "DHT_SEND for %pI4\n", &ip);
585 for (i = 0; i < BATADV_DAT_CANDIDATES_NUM; i++) {
586 if (cand[i].type == BATADV_DAT_CANDIDATE_NOT_FOUND)
589 neigh_node = batadv_orig_node_get_router(cand[i].orig_node);
593 tmp_skb = pskb_copy(skb, GFP_ATOMIC);
594 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, tmp_skb,
601 send_status = batadv_send_skb_packet(tmp_skb,
602 neigh_node->if_incoming,
604 if (send_status == NET_XMIT_SUCCESS) {
605 /* count the sent packet */
606 switch (packet_subtype) {
607 case BATADV_P_DAT_DHT_GET:
608 batadv_inc_counter(bat_priv,
609 BATADV_CNT_DAT_GET_TX);
611 case BATADV_P_DAT_DHT_PUT:
612 batadv_inc_counter(bat_priv,
613 BATADV_CNT_DAT_PUT_TX);
617 /* packet sent to a candidate: return true */
621 batadv_neigh_node_free_ref(neigh_node);
623 batadv_orig_node_free_ref(cand[i].orig_node);
632 * batadv_dat_tvlv_container_update - update the dat tvlv container after dat
634 * @bat_priv: the bat priv with all the soft interface information
636 static void batadv_dat_tvlv_container_update(struct batadv_priv *bat_priv)
640 dat_mode = atomic_read(&bat_priv->distributed_arp_table);
644 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_DAT, 1);
647 batadv_tvlv_container_register(bat_priv, BATADV_TVLV_DAT, 1,
654 * batadv_dat_status_update - update the dat tvlv container after dat
656 * @net_dev: the soft interface net device
658 void batadv_dat_status_update(struct net_device *net_dev)
660 struct batadv_priv *bat_priv = netdev_priv(net_dev);
661 batadv_dat_tvlv_container_update(bat_priv);
665 * batadv_gw_tvlv_ogm_handler_v1 - process incoming dat tvlv container
666 * @bat_priv: the bat priv with all the soft interface information
667 * @orig: the orig_node of the ogm
668 * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
669 * @tvlv_value: tvlv buffer containing the gateway data
670 * @tvlv_value_len: tvlv buffer length
672 static void batadv_dat_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
673 struct batadv_orig_node *orig,
676 uint16_t tvlv_value_len)
678 if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
679 orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_DAT;
681 orig->capabilities |= BATADV_ORIG_CAPA_HAS_DAT;
685 * batadv_dat_hash_free - free the local DAT hash table
686 * @bat_priv: the bat priv with all the soft interface information
688 static void batadv_dat_hash_free(struct batadv_priv *bat_priv)
690 if (!bat_priv->dat.hash)
693 __batadv_dat_purge(bat_priv, NULL);
695 batadv_hash_destroy(bat_priv->dat.hash);
697 bat_priv->dat.hash = NULL;
701 * batadv_dat_init - initialise the DAT internals
702 * @bat_priv: the bat priv with all the soft interface information
704 int batadv_dat_init(struct batadv_priv *bat_priv)
706 if (bat_priv->dat.hash)
709 bat_priv->dat.hash = batadv_hash_new(1024);
711 if (!bat_priv->dat.hash)
714 batadv_dat_start_timer(bat_priv);
716 batadv_tvlv_handler_register(bat_priv, batadv_dat_tvlv_ogm_handler_v1,
717 NULL, BATADV_TVLV_DAT, 1,
718 BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
719 batadv_dat_tvlv_container_update(bat_priv);
724 * batadv_dat_free - free the DAT internals
725 * @bat_priv: the bat priv with all the soft interface information
727 void batadv_dat_free(struct batadv_priv *bat_priv)
729 batadv_tvlv_container_unregister(bat_priv, BATADV_TVLV_DAT, 1);
730 batadv_tvlv_handler_unregister(bat_priv, BATADV_TVLV_DAT, 1);
732 cancel_delayed_work_sync(&bat_priv->dat.work);
734 batadv_dat_hash_free(bat_priv);
738 * batadv_dat_cache_seq_print_text - print the local DAT hash table
739 * @seq: seq file to print on
742 int batadv_dat_cache_seq_print_text(struct seq_file *seq, void *offset)
744 struct net_device *net_dev = (struct net_device *)seq->private;
745 struct batadv_priv *bat_priv = netdev_priv(net_dev);
746 struct batadv_hashtable *hash = bat_priv->dat.hash;
747 struct batadv_dat_entry *dat_entry;
748 struct batadv_hard_iface *primary_if;
749 struct hlist_head *head;
750 unsigned long last_seen_jiffies;
751 int last_seen_msecs, last_seen_secs, last_seen_mins;
754 primary_if = batadv_seq_print_text_primary_if_get(seq);
758 seq_printf(seq, "Distributed ARP Table (%s):\n", net_dev->name);
759 seq_printf(seq, " %-7s %-13s %5s\n", "IPv4", "MAC",
762 for (i = 0; i < hash->size; i++) {
763 head = &hash->table[i];
766 hlist_for_each_entry_rcu(dat_entry, head, hash_entry) {
767 last_seen_jiffies = jiffies - dat_entry->last_update;
768 last_seen_msecs = jiffies_to_msecs(last_seen_jiffies);
769 last_seen_mins = last_seen_msecs / 60000;
770 last_seen_msecs = last_seen_msecs % 60000;
771 last_seen_secs = last_seen_msecs / 1000;
773 seq_printf(seq, " * %15pI4 %14pM %6i:%02i\n",
774 &dat_entry->ip, dat_entry->mac_addr,
775 last_seen_mins, last_seen_secs);
782 batadv_hardif_free_ref(primary_if);
787 * batadv_arp_get_type - parse an ARP packet and gets the type
788 * @bat_priv: the bat priv with all the soft interface information
789 * @skb: packet to analyse
790 * @hdr_size: size of the possible header before the ARP packet in the skb
792 * Returns the ARP type if the skb contains a valid ARP packet, 0 otherwise.
794 static uint16_t batadv_arp_get_type(struct batadv_priv *bat_priv,
795 struct sk_buff *skb, int hdr_size)
797 struct arphdr *arphdr;
798 struct ethhdr *ethhdr;
799 __be32 ip_src, ip_dst;
800 uint8_t *hw_src, *hw_dst;
803 /* pull the ethernet header */
804 if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN)))
807 ethhdr = (struct ethhdr *)(skb->data + hdr_size);
809 if (ethhdr->h_proto != htons(ETH_P_ARP))
812 /* pull the ARP payload */
813 if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN +
814 arp_hdr_len(skb->dev))))
817 arphdr = (struct arphdr *)(skb->data + hdr_size + ETH_HLEN);
819 /* check whether the ARP packet carries a valid IP information */
820 if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
823 if (arphdr->ar_pro != htons(ETH_P_IP))
826 if (arphdr->ar_hln != ETH_ALEN)
829 if (arphdr->ar_pln != 4)
832 /* Check for bad reply/request. If the ARP message is not sane, DAT
833 * will simply ignore it
835 ip_src = batadv_arp_ip_src(skb, hdr_size);
836 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
837 if (ipv4_is_loopback(ip_src) || ipv4_is_multicast(ip_src) ||
838 ipv4_is_loopback(ip_dst) || ipv4_is_multicast(ip_dst) ||
839 ipv4_is_zeronet(ip_src) || ipv4_is_lbcast(ip_src) ||
840 ipv4_is_zeronet(ip_dst) || ipv4_is_lbcast(ip_dst))
843 hw_src = batadv_arp_hw_src(skb, hdr_size);
844 if (is_zero_ether_addr(hw_src) || is_multicast_ether_addr(hw_src))
847 /* don't care about the destination MAC address in ARP requests */
848 if (arphdr->ar_op != htons(ARPOP_REQUEST)) {
849 hw_dst = batadv_arp_hw_dst(skb, hdr_size);
850 if (is_zero_ether_addr(hw_dst) ||
851 is_multicast_ether_addr(hw_dst))
855 type = ntohs(arphdr->ar_op);
861 * batadv_dat_snoop_outgoing_arp_request - snoop the ARP request and try to
863 * @bat_priv: the bat priv with all the soft interface information
864 * @skb: packet to check
866 * Returns true if the message has been sent to the dht candidates, false
867 * otherwise. In case of a positive return value the message has to be enqueued
868 * to permit the fallback.
870 bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
874 __be32 ip_dst, ip_src;
877 struct batadv_dat_entry *dat_entry = NULL;
878 struct sk_buff *skb_new;
880 if (!atomic_read(&bat_priv->distributed_arp_table))
883 type = batadv_arp_get_type(bat_priv, skb, 0);
884 /* If the node gets an ARP_REQUEST it has to send a DHT_GET unicast
885 * message to the selected DHT candidates
887 if (type != ARPOP_REQUEST)
890 batadv_dbg_arp(bat_priv, skb, type, 0, "Parsing outgoing ARP REQUEST");
892 ip_src = batadv_arp_ip_src(skb, 0);
893 hw_src = batadv_arp_hw_src(skb, 0);
894 ip_dst = batadv_arp_ip_dst(skb, 0);
896 batadv_dat_entry_add(bat_priv, ip_src, hw_src);
898 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst);
900 /* If the ARP request is destined for a local client the local
901 * client will answer itself. DAT would only generate a
904 * Moreover, if the soft-interface is enslaved into a bridge, an
905 * additional DAT answer may trigger kernel warnings about
906 * a packet coming from the wrong port.
908 if (batadv_is_my_client(bat_priv, dat_entry->mac_addr)) {
913 skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
914 bat_priv->soft_iface, ip_dst, hw_src,
915 dat_entry->mac_addr, hw_src);
919 skb_reset_mac_header(skb_new);
920 skb_new->protocol = eth_type_trans(skb_new,
921 bat_priv->soft_iface);
922 bat_priv->stats.rx_packets++;
923 bat_priv->stats.rx_bytes += skb->len + ETH_HLEN;
924 bat_priv->soft_iface->last_rx = jiffies;
927 batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP request replied locally\n");
930 /* Send the request to the DHT */
931 ret = batadv_dat_send_data(bat_priv, skb, ip_dst,
932 BATADV_P_DAT_DHT_GET);
936 batadv_dat_entry_free_ref(dat_entry);
941 * batadv_dat_snoop_incoming_arp_request - snoop the ARP request and try to
942 * answer using the local DAT storage
943 * @bat_priv: the bat priv with all the soft interface information
944 * @skb: packet to check
945 * @hdr_size: size of the encapsulation header
947 * Returns true if the request has been answered, false otherwise.
949 bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
950 struct sk_buff *skb, int hdr_size)
953 __be32 ip_src, ip_dst;
955 struct sk_buff *skb_new;
956 struct batadv_dat_entry *dat_entry = NULL;
960 if (!atomic_read(&bat_priv->distributed_arp_table))
963 type = batadv_arp_get_type(bat_priv, skb, hdr_size);
964 if (type != ARPOP_REQUEST)
967 hw_src = batadv_arp_hw_src(skb, hdr_size);
968 ip_src = batadv_arp_ip_src(skb, hdr_size);
969 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
971 batadv_dbg_arp(bat_priv, skb, type, hdr_size,
972 "Parsing incoming ARP REQUEST");
974 batadv_dat_entry_add(bat_priv, ip_src, hw_src);
976 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst);
980 skb_new = arp_create(ARPOP_REPLY, ETH_P_ARP, ip_src,
981 bat_priv->soft_iface, ip_dst, hw_src,
982 dat_entry->mac_addr, hw_src);
987 /* To preserve backwards compatibility, the node has choose the outgoing
988 * format based on the incoming request packet type. The assumption is
989 * that a node not using the 4addr packet format doesn't support it.
991 if (hdr_size == sizeof(struct batadv_unicast_4addr_packet))
992 err = batadv_send_skb_unicast_4addr(bat_priv, skb_new,
993 BATADV_P_DAT_CACHE_REPLY);
995 err = batadv_send_skb_unicast(bat_priv, skb_new);
998 batadv_inc_counter(bat_priv, BATADV_CNT_DAT_CACHED_REPLY_TX);
1003 batadv_dat_entry_free_ref(dat_entry);
1010 * batadv_dat_snoop_outgoing_arp_reply - snoop the ARP reply and fill the DHT
1011 * @bat_priv: the bat priv with all the soft interface information
1012 * @skb: packet to check
1014 void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv,
1015 struct sk_buff *skb)
1018 __be32 ip_src, ip_dst;
1019 uint8_t *hw_src, *hw_dst;
1021 if (!atomic_read(&bat_priv->distributed_arp_table))
1024 type = batadv_arp_get_type(bat_priv, skb, 0);
1025 if (type != ARPOP_REPLY)
1028 batadv_dbg_arp(bat_priv, skb, type, 0, "Parsing outgoing ARP REPLY");
1030 hw_src = batadv_arp_hw_src(skb, 0);
1031 ip_src = batadv_arp_ip_src(skb, 0);
1032 hw_dst = batadv_arp_hw_dst(skb, 0);
1033 ip_dst = batadv_arp_ip_dst(skb, 0);
1035 batadv_dat_entry_add(bat_priv, ip_src, hw_src);
1036 batadv_dat_entry_add(bat_priv, ip_dst, hw_dst);
1038 /* Send the ARP reply to the candidates for both the IP addresses that
1039 * the node obtained from the ARP reply
1041 batadv_dat_send_data(bat_priv, skb, ip_src, BATADV_P_DAT_DHT_PUT);
1042 batadv_dat_send_data(bat_priv, skb, ip_dst, BATADV_P_DAT_DHT_PUT);
1045 * batadv_dat_snoop_incoming_arp_reply - snoop the ARP reply and fill the local
1047 * @bat_priv: the bat priv with all the soft interface information
1048 * @skb: packet to check
1049 * @hdr_size: size of the encapsulation header
1051 bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
1052 struct sk_buff *skb, int hdr_size)
1055 __be32 ip_src, ip_dst;
1056 uint8_t *hw_src, *hw_dst;
1059 if (!atomic_read(&bat_priv->distributed_arp_table))
1062 type = batadv_arp_get_type(bat_priv, skb, hdr_size);
1063 if (type != ARPOP_REPLY)
1066 batadv_dbg_arp(bat_priv, skb, type, hdr_size,
1067 "Parsing incoming ARP REPLY");
1069 hw_src = batadv_arp_hw_src(skb, hdr_size);
1070 ip_src = batadv_arp_ip_src(skb, hdr_size);
1071 hw_dst = batadv_arp_hw_dst(skb, hdr_size);
1072 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
1074 /* Update our internal cache with both the IP addresses the node got
1075 * within the ARP reply
1077 batadv_dat_entry_add(bat_priv, ip_src, hw_src);
1078 batadv_dat_entry_add(bat_priv, ip_dst, hw_dst);
1080 /* if this REPLY is directed to a client of mine, let's deliver the
1081 * packet to the interface
1083 ret = !batadv_is_my_client(bat_priv, hw_dst);
1087 /* if ret == false -> packet has to be delivered to the interface */
1092 * batadv_dat_drop_broadcast_packet - check if an ARP request has to be dropped
1093 * (because the node has already obtained the reply via DAT) or not
1094 * @bat_priv: the bat priv with all the soft interface information
1095 * @forw_packet: the broadcast packet
1097 * Returns true if the node can drop the packet, false otherwise.
1099 bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv,
1100 struct batadv_forw_packet *forw_packet)
1104 struct batadv_dat_entry *dat_entry = NULL;
1106 const size_t bcast_len = sizeof(struct batadv_bcast_packet);
1108 if (!atomic_read(&bat_priv->distributed_arp_table))
1111 /* If this packet is an ARP_REQUEST and the node already has the
1112 * information that it is going to ask, then the packet can be dropped
1114 if (forw_packet->num_packets)
1117 type = batadv_arp_get_type(bat_priv, forw_packet->skb, bcast_len);
1118 if (type != ARPOP_REQUEST)
1121 ip_dst = batadv_arp_ip_dst(forw_packet->skb, bcast_len);
1122 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip_dst);
1123 /* check if the node already got this entry */
1125 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1126 "ARP Request for %pI4: fallback\n", &ip_dst);
1130 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1131 "ARP Request for %pI4: fallback prevented\n", &ip_dst);
1136 batadv_dat_entry_free_ref(dat_entry);