1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (C) B.A.T.M.A.N. contributors:
3 *
4 * Antonio Quartulli
5 */
6
7#include "distributed-arp-table.h"
8#include "main.h"
9
10#include <asm/unaligned.h>
11#include <linux/atomic.h>
12#include <linux/bitops.h>
13#include <linux/byteorder/generic.h>
14#include <linux/container_of.h>
15#include <linux/errno.h>
16#include <linux/etherdevice.h>
17#include <linux/gfp.h>
18#include <linux/if_arp.h>
19#include <linux/if_ether.h>
20#include <linux/if_vlan.h>
21#include <linux/in.h>
22#include <linux/ip.h>
23#include <linux/jiffies.h>
24#include <linux/kref.h>
25#include <linux/list.h>
26#include <linux/netlink.h>
27#include <linux/rculist.h>
28#include <linux/rcupdate.h>
29#include <linux/skbuff.h>
30#include <linux/slab.h>
31#include <linux/spinlock.h>
32#include <linux/stddef.h>
33#include <linux/string.h>
34#include <linux/udp.h>
35#include <linux/workqueue.h>
36#include <net/arp.h>
37#include <net/genetlink.h>
38#include <net/netlink.h>
39#include <net/sock.h>
40#include <uapi/linux/batman_adv.h>
41
42#include "bridge_loop_avoidance.h"
43#include "hard-interface.h"
44#include "hash.h"
45#include "log.h"
46#include "netlink.h"
47#include "originator.h"
48#include "send.h"
49#include "soft-interface.h"
50#include "translation-table.h"
51#include "tvlv.h"
52
53enum batadv_bootpop {
54 BATADV_BOOTREPLY = 2,
55};
56
57enum batadv_boothtype {
58 BATADV_HTYPE_ETHERNET = 1,
59};
60
61enum batadv_dhcpoptioncode {
62 BATADV_DHCP_OPT_PAD = 0,
63 BATADV_DHCP_OPT_MSG_TYPE = 53,
64 BATADV_DHCP_OPT_END = 255,
65};
66
67enum batadv_dhcptype {
68 BATADV_DHCPACK = 5,
69};
70
71/* { 99, 130, 83, 99 } */
72#define BATADV_DHCP_MAGIC 1669485411
73
74struct batadv_dhcp_packet {
75 __u8 op;
76 __u8 htype;
77 __u8 hlen;
78 __u8 hops;
79 __be32 xid;
80 __be16 secs;
81 __be16 flags;
82 __be32 ciaddr;
83 __be32 yiaddr;
84 __be32 siaddr;
85 __be32 giaddr;
86 __u8 chaddr[16];
87 __u8 sname[64];
88 __u8 file[128];
89 __be32 magic;
90 /* __u8 options[]; */
91};
92
93#define BATADV_DHCP_YIADDR_LEN sizeof(((struct batadv_dhcp_packet *)0)->yiaddr)
94#define BATADV_DHCP_CHADDR_LEN sizeof(((struct batadv_dhcp_packet *)0)->chaddr)
95
96static void batadv_dat_purge(struct work_struct *work);
97
98/**
99 * batadv_dat_start_timer() - initialise the DAT periodic worker
100 * @bat_priv: the bat priv with all the soft interface information
101 */
102static void batadv_dat_start_timer(struct batadv_priv *bat_priv)
103{
104 queue_delayed_work(wq: batadv_event_workqueue, dwork: &bat_priv->dat.work,
105 delay: msecs_to_jiffies(m: 10000));
106}
107
108/**
109 * batadv_dat_entry_release() - release dat_entry from lists and queue for free
110 * after rcu grace period
111 * @ref: kref pointer of the dat_entry
112 */
113static void batadv_dat_entry_release(struct kref *ref)
114{
115 struct batadv_dat_entry *dat_entry;
116
117 dat_entry = container_of(ref, struct batadv_dat_entry, refcount);
118
119 kfree_rcu(dat_entry, rcu);
120}
121
122/**
123 * batadv_dat_entry_put() - decrement the dat_entry refcounter and possibly
124 * release it
125 * @dat_entry: dat_entry to be free'd
126 */
127static void batadv_dat_entry_put(struct batadv_dat_entry *dat_entry)
128{
129 if (!dat_entry)
130 return;
131
132 kref_put(kref: &dat_entry->refcount, release: batadv_dat_entry_release);
133}
134
135/**
136 * batadv_dat_to_purge() - check whether a dat_entry has to be purged or not
137 * @dat_entry: the entry to check
138 *
139 * Return: true if the entry has to be purged now, false otherwise.
140 */
141static bool batadv_dat_to_purge(struct batadv_dat_entry *dat_entry)
142{
143 return batadv_has_timed_out(timestamp: dat_entry->last_update,
144 BATADV_DAT_ENTRY_TIMEOUT);
145}
146
147/**
148 * __batadv_dat_purge() - delete entries from the DAT local storage
149 * @bat_priv: the bat priv with all the soft interface information
150 * @to_purge: function in charge to decide whether an entry has to be purged or
151 * not. This function takes the dat_entry as argument and has to
152 * returns a boolean value: true is the entry has to be deleted,
153 * false otherwise
154 *
155 * Loops over each entry in the DAT local storage and deletes it if and only if
156 * the to_purge function passed as argument returns true.
157 */
158static void __batadv_dat_purge(struct batadv_priv *bat_priv,
159 bool (*to_purge)(struct batadv_dat_entry *))
160{
161 spinlock_t *list_lock; /* protects write access to the hash lists */
162 struct batadv_dat_entry *dat_entry;
163 struct hlist_node *node_tmp;
164 struct hlist_head *head;
165 u32 i;
166
167 if (!bat_priv->dat.hash)
168 return;
169
170 for (i = 0; i < bat_priv->dat.hash->size; i++) {
171 head = &bat_priv->dat.hash->table[i];
172 list_lock = &bat_priv->dat.hash->list_locks[i];
173
174 spin_lock_bh(lock: list_lock);
175 hlist_for_each_entry_safe(dat_entry, node_tmp, head,
176 hash_entry) {
177 /* if a helper function has been passed as parameter,
178 * ask it if the entry has to be purged or not
179 */
180 if (to_purge && !to_purge(dat_entry))
181 continue;
182
183 hlist_del_rcu(n: &dat_entry->hash_entry);
184 batadv_dat_entry_put(dat_entry);
185 }
186 spin_unlock_bh(lock: list_lock);
187 }
188}
189
190/**
191 * batadv_dat_purge() - periodic task that deletes old entries from the local
192 * DAT hash table
193 * @work: kernel work struct
194 */
195static void batadv_dat_purge(struct work_struct *work)
196{
197 struct delayed_work *delayed_work;
198 struct batadv_priv_dat *priv_dat;
199 struct batadv_priv *bat_priv;
200
201 delayed_work = to_delayed_work(work);
202 priv_dat = container_of(delayed_work, struct batadv_priv_dat, work);
203 bat_priv = container_of(priv_dat, struct batadv_priv, dat);
204
205 __batadv_dat_purge(bat_priv, to_purge: batadv_dat_to_purge);
206 batadv_dat_start_timer(bat_priv);
207}
208
209/**
210 * batadv_compare_dat() - comparing function used in the local DAT hash table
211 * @node: node in the local table
212 * @data2: second object to compare the node to
213 *
214 * Return: true if the two entries are the same, false otherwise.
215 */
216static bool batadv_compare_dat(const struct hlist_node *node, const void *data2)
217{
218 const void *data1 = container_of(node, struct batadv_dat_entry,
219 hash_entry);
220
221 return memcmp(p: data1, q: data2, size: sizeof(__be32)) == 0;
222}
223
224/**
225 * batadv_arp_hw_src() - extract the hw_src field from an ARP packet
226 * @skb: ARP packet
227 * @hdr_size: size of the possible header before the ARP packet
228 *
229 * Return: the value of the hw_src field in the ARP packet.
230 */
231static u8 *batadv_arp_hw_src(struct sk_buff *skb, int hdr_size)
232{
233 u8 *addr;
234
235 addr = (u8 *)(skb->data + hdr_size);
236 addr += ETH_HLEN + sizeof(struct arphdr);
237
238 return addr;
239}
240
241/**
242 * batadv_arp_ip_src() - extract the ip_src field from an ARP packet
243 * @skb: ARP packet
244 * @hdr_size: size of the possible header before the ARP packet
245 *
246 * Return: the value of the ip_src field in the ARP packet.
247 */
248static __be32 batadv_arp_ip_src(struct sk_buff *skb, int hdr_size)
249{
250 return *(__force __be32 *)(batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN);
251}
252
253/**
254 * batadv_arp_hw_dst() - extract the hw_dst field from an ARP packet
255 * @skb: ARP packet
256 * @hdr_size: size of the possible header before the ARP packet
257 *
258 * Return: the value of the hw_dst field in the ARP packet.
259 */
260static u8 *batadv_arp_hw_dst(struct sk_buff *skb, int hdr_size)
261{
262 return batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN + 4;
263}
264
265/**
266 * batadv_arp_ip_dst() - extract the ip_dst field from an ARP packet
267 * @skb: ARP packet
268 * @hdr_size: size of the possible header before the ARP packet
269 *
270 * Return: the value of the ip_dst field in the ARP packet.
271 */
272static __be32 batadv_arp_ip_dst(struct sk_buff *skb, int hdr_size)
273{
274 u8 *dst = batadv_arp_hw_src(skb, hdr_size) + ETH_ALEN * 2 + 4;
275
276 return *(__force __be32 *)dst;
277}
278
279/**
280 * batadv_hash_dat() - compute the hash value for an IP address
281 * @data: data to hash
282 * @size: size of the hash table
283 *
284 * Return: the selected index in the hash table for the given data.
285 */
286static u32 batadv_hash_dat(const void *data, u32 size)
287{
288 u32 hash = 0;
289 const struct batadv_dat_entry *dat = data;
290 const unsigned char *key;
291 __be16 vid;
292 u32 i;
293
294 key = (__force const unsigned char *)&dat->ip;
295 for (i = 0; i < sizeof(dat->ip); i++) {
296 hash += key[i];
297 hash += (hash << 10);
298 hash ^= (hash >> 6);
299 }
300
301 vid = htons(dat->vid);
302 key = (__force const unsigned char *)&vid;
303 for (i = 0; i < sizeof(dat->vid); i++) {
304 hash += key[i];
305 hash += (hash << 10);
306 hash ^= (hash >> 6);
307 }
308
309 hash += (hash << 3);
310 hash ^= (hash >> 11);
311 hash += (hash << 15);
312
313 return hash % size;
314}
315
316/**
317 * batadv_dat_entry_hash_find() - look for a given dat_entry in the local hash
318 * table
319 * @bat_priv: the bat priv with all the soft interface information
320 * @ip: search key
321 * @vid: VLAN identifier
322 *
323 * Return: the dat_entry if found, NULL otherwise.
324 */
325static struct batadv_dat_entry *
326batadv_dat_entry_hash_find(struct batadv_priv *bat_priv, __be32 ip,
327 unsigned short vid)
328{
329 struct hlist_head *head;
330 struct batadv_dat_entry to_find, *dat_entry, *dat_entry_tmp = NULL;
331 struct batadv_hashtable *hash = bat_priv->dat.hash;
332 u32 index;
333
334 if (!hash)
335 return NULL;
336
337 to_find.ip = ip;
338 to_find.vid = vid;
339
340 index = batadv_hash_dat(data: &to_find, size: hash->size);
341 head = &hash->table[index];
342
343 rcu_read_lock();
344 hlist_for_each_entry_rcu(dat_entry, head, hash_entry) {
345 if (dat_entry->ip != ip)
346 continue;
347
348 if (!kref_get_unless_zero(kref: &dat_entry->refcount))
349 continue;
350
351 dat_entry_tmp = dat_entry;
352 break;
353 }
354 rcu_read_unlock();
355
356 return dat_entry_tmp;
357}
358
359/**
360 * batadv_dat_entry_add() - add a new dat entry or update it if already exists
361 * @bat_priv: the bat priv with all the soft interface information
362 * @ip: ipv4 to add/edit
363 * @mac_addr: mac address to assign to the given ipv4
364 * @vid: VLAN identifier
365 */
366static void batadv_dat_entry_add(struct batadv_priv *bat_priv, __be32 ip,
367 u8 *mac_addr, unsigned short vid)
368{
369 struct batadv_dat_entry *dat_entry;
370 int hash_added;
371
372 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip, vid);
373 /* if this entry is already known, just update it */
374 if (dat_entry) {
375 if (!batadv_compare_eth(data1: dat_entry->mac_addr, data2: mac_addr))
376 ether_addr_copy(dst: dat_entry->mac_addr, src: mac_addr);
377 dat_entry->last_update = jiffies;
378 batadv_dbg(BATADV_DBG_DAT, bat_priv,
379 "Entry updated: %pI4 %pM (vid: %d)\n",
380 &dat_entry->ip, dat_entry->mac_addr,
381 batadv_print_vid(vid));
382 goto out;
383 }
384
385 dat_entry = kmalloc(size: sizeof(*dat_entry), GFP_ATOMIC);
386 if (!dat_entry)
387 goto out;
388
389 dat_entry->ip = ip;
390 dat_entry->vid = vid;
391 ether_addr_copy(dst: dat_entry->mac_addr, src: mac_addr);
392 dat_entry->last_update = jiffies;
393 kref_init(kref: &dat_entry->refcount);
394
395 kref_get(kref: &dat_entry->refcount);
396 hash_added = batadv_hash_add(hash: bat_priv->dat.hash, compare: batadv_compare_dat,
397 choose: batadv_hash_dat, data: dat_entry,
398 data_node: &dat_entry->hash_entry);
399
400 if (unlikely(hash_added != 0)) {
401 /* remove the reference for the hash */
402 batadv_dat_entry_put(dat_entry);
403 goto out;
404 }
405
406 batadv_dbg(BATADV_DBG_DAT, bat_priv, "New entry added: %pI4 %pM (vid: %d)\n",
407 &dat_entry->ip, dat_entry->mac_addr, batadv_print_vid(vid));
408
409out:
410 batadv_dat_entry_put(dat_entry);
411}
412
413#ifdef CONFIG_BATMAN_ADV_DEBUG
414
415/**
416 * batadv_dbg_arp() - print a debug message containing all the ARP packet
417 * details
418 * @bat_priv: the bat priv with all the soft interface information
419 * @skb: ARP packet
420 * @hdr_size: size of the possible header before the ARP packet
421 * @msg: message to print together with the debugging information
422 */
423static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb,
424 int hdr_size, char *msg)
425{
426 struct batadv_unicast_4addr_packet *unicast_4addr_packet;
427 struct batadv_bcast_packet *bcast_pkt;
428 u8 *orig_addr;
429 __be32 ip_src, ip_dst;
430
431 if (msg)
432 batadv_dbg(BATADV_DBG_DAT, bat_priv, "%s\n", msg);
433
434 ip_src = batadv_arp_ip_src(skb, hdr_size);
435 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
436 batadv_dbg(BATADV_DBG_DAT, bat_priv,
437 "ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]\n",
438 batadv_arp_hw_src(skb, hdr_size), &ip_src,
439 batadv_arp_hw_dst(skb, hdr_size), &ip_dst);
440
441 if (hdr_size < sizeof(struct batadv_unicast_packet))
442 return;
443
444 unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
445
446 switch (unicast_4addr_packet->u.packet_type) {
447 case BATADV_UNICAST:
448 batadv_dbg(BATADV_DBG_DAT, bat_priv,
449 "* encapsulated within a UNICAST packet\n");
450 break;
451 case BATADV_UNICAST_4ADDR:
452 batadv_dbg(BATADV_DBG_DAT, bat_priv,
453 "* encapsulated within a UNICAST_4ADDR packet (src: %pM)\n",
454 unicast_4addr_packet->src);
455 switch (unicast_4addr_packet->subtype) {
456 case BATADV_P_DAT_DHT_PUT:
457 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_PUT\n");
458 break;
459 case BATADV_P_DAT_DHT_GET:
460 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DAT_DHT_GET\n");
461 break;
462 case BATADV_P_DAT_CACHE_REPLY:
463 batadv_dbg(BATADV_DBG_DAT, bat_priv,
464 "* type: DAT_CACHE_REPLY\n");
465 break;
466 case BATADV_P_DATA:
467 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: DATA\n");
468 break;
469 default:
470 batadv_dbg(BATADV_DBG_DAT, bat_priv, "* type: Unknown (%u)!\n",
471 unicast_4addr_packet->u.packet_type);
472 }
473 break;
474 case BATADV_BCAST:
475 bcast_pkt = (struct batadv_bcast_packet *)unicast_4addr_packet;
476 orig_addr = bcast_pkt->orig;
477 batadv_dbg(BATADV_DBG_DAT, bat_priv,
478 "* encapsulated within a BCAST packet (src: %pM)\n",
479 orig_addr);
480 break;
481 default:
482 batadv_dbg(BATADV_DBG_DAT, bat_priv,
483 "* encapsulated within an unknown packet type (0x%x)\n",
484 unicast_4addr_packet->u.packet_type);
485 }
486}
487
488#else
489
490static void batadv_dbg_arp(struct batadv_priv *bat_priv, struct sk_buff *skb,
491 int hdr_size, char *msg)
492{
493}
494
495#endif /* CONFIG_BATMAN_ADV_DEBUG */
496
497/**
498 * batadv_is_orig_node_eligible() - check whether a node can be a DHT candidate
499 * @res: the array with the already selected candidates
500 * @select: number of already selected candidates
501 * @tmp_max: address of the currently evaluated node
502 * @max: current round max address
503 * @last_max: address of the last selected candidate
504 * @candidate: orig_node under evaluation
505 * @max_orig_node: last selected candidate
506 *
507 * Return: true if the node has been elected as next candidate or false
508 * otherwise.
509 */
510static bool batadv_is_orig_node_eligible(struct batadv_dat_candidate *res,
511 int select, batadv_dat_addr_t tmp_max,
512 batadv_dat_addr_t max,
513 batadv_dat_addr_t last_max,
514 struct batadv_orig_node *candidate,
515 struct batadv_orig_node *max_orig_node)
516{
517 bool ret = false;
518 int j;
519
520 /* check if orig node candidate is running DAT */
521 if (!test_bit(BATADV_ORIG_CAPA_HAS_DAT, &candidate->capabilities))
522 goto out;
523
524 /* Check if this node has already been selected... */
525 for (j = 0; j < select; j++)
526 if (res[j].orig_node == candidate)
527 break;
528 /* ..and possibly skip it */
529 if (j < select)
530 goto out;
531 /* sanity check: has it already been selected? This should not happen */
532 if (tmp_max > last_max)
533 goto out;
534 /* check if during this iteration an originator with a closer dht
535 * address has already been found
536 */
537 if (tmp_max < max)
538 goto out;
539 /* this is an hash collision with the temporary selected node. Choose
540 * the one with the lowest address
541 */
542 if (tmp_max == max && max_orig_node &&
543 batadv_compare_eth(data1: candidate->orig, data2: max_orig_node->orig))
544 goto out;
545
546 ret = true;
547out:
548 return ret;
549}
550
551/**
552 * batadv_choose_next_candidate() - select the next DHT candidate
553 * @bat_priv: the bat priv with all the soft interface information
554 * @cands: candidates array
555 * @select: number of candidates already present in the array
556 * @ip_key: key to look up in the DHT
557 * @last_max: pointer where the address of the selected candidate will be saved
558 */
559static void batadv_choose_next_candidate(struct batadv_priv *bat_priv,
560 struct batadv_dat_candidate *cands,
561 int select, batadv_dat_addr_t ip_key,
562 batadv_dat_addr_t *last_max)
563{
564 batadv_dat_addr_t max = 0;
565 batadv_dat_addr_t tmp_max = 0;
566 struct batadv_orig_node *orig_node, *max_orig_node = NULL;
567 struct batadv_hashtable *hash = bat_priv->orig_hash;
568 struct hlist_head *head;
569 int i;
570
571 /* if no node is eligible as candidate, leave the candidate type as
572 * NOT_FOUND
573 */
574 cands[select].type = BATADV_DAT_CANDIDATE_NOT_FOUND;
575
576 /* iterate over the originator list and find the node with the closest
577 * dat_address which has not been selected yet
578 */
579 for (i = 0; i < hash->size; i++) {
580 head = &hash->table[i];
581
582 rcu_read_lock();
583 hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
584 /* the dht space is a ring using unsigned addresses */
585 tmp_max = BATADV_DAT_ADDR_MAX - orig_node->dat_addr +
586 ip_key;
587
588 if (!batadv_is_orig_node_eligible(res: cands, select,
589 tmp_max, max,
590 last_max: *last_max, candidate: orig_node,
591 max_orig_node))
592 continue;
593
594 if (!kref_get_unless_zero(kref: &orig_node->refcount))
595 continue;
596
597 max = tmp_max;
598 batadv_orig_node_put(orig_node: max_orig_node);
599 max_orig_node = orig_node;
600 }
601 rcu_read_unlock();
602 }
603 if (max_orig_node) {
604 cands[select].type = BATADV_DAT_CANDIDATE_ORIG;
605 cands[select].orig_node = max_orig_node;
606 batadv_dbg(BATADV_DBG_DAT, bat_priv,
607 "dat_select_candidates() %d: selected %pM addr=%u dist=%u\n",
608 select, max_orig_node->orig, max_orig_node->dat_addr,
609 max);
610 }
611 *last_max = max;
612}
613
614/**
615 * batadv_dat_select_candidates() - select the nodes which the DHT message has
616 * to be sent to
617 * @bat_priv: the bat priv with all the soft interface information
618 * @ip_dst: ipv4 to look up in the DHT
619 * @vid: VLAN identifier
620 *
621 * An originator O is selected if and only if its DHT_ID value is one of three
622 * closest values (from the LEFT, with wrap around if needed) then the hash
623 * value of the key. ip_dst is the key.
624 *
625 * Return: the candidate array of size BATADV_DAT_CANDIDATE_NUM.
626 */
627static struct batadv_dat_candidate *
628batadv_dat_select_candidates(struct batadv_priv *bat_priv, __be32 ip_dst,
629 unsigned short vid)
630{
631 int select;
632 batadv_dat_addr_t last_max = BATADV_DAT_ADDR_MAX, ip_key;
633 struct batadv_dat_candidate *res;
634 struct batadv_dat_entry dat;
635
636 if (!bat_priv->orig_hash)
637 return NULL;
638
639 res = kmalloc_array(BATADV_DAT_CANDIDATES_NUM, size: sizeof(*res),
640 GFP_ATOMIC);
641 if (!res)
642 return NULL;
643
644 dat.ip = ip_dst;
645 dat.vid = vid;
646 ip_key = (batadv_dat_addr_t)batadv_hash_dat(data: &dat,
647 BATADV_DAT_ADDR_MAX);
648
649 batadv_dbg(BATADV_DBG_DAT, bat_priv,
650 "%s(): IP=%pI4 hash(IP)=%u\n", __func__, &ip_dst,
651 ip_key);
652
653 for (select = 0; select < BATADV_DAT_CANDIDATES_NUM; select++)
654 batadv_choose_next_candidate(bat_priv, cands: res, select, ip_key,
655 last_max: &last_max);
656
657 return res;
658}
659
660/**
661 * batadv_dat_forward_data() - copy and send payload to the selected candidates
662 * @bat_priv: the bat priv with all the soft interface information
663 * @skb: payload to send
664 * @ip: the DHT key
665 * @vid: VLAN identifier
666 * @packet_subtype: unicast4addr packet subtype to use
667 *
668 * This function copies the skb with pskb_copy() and is sent as a unicast packet
669 * to each of the selected candidates.
670 *
671 * Return: true if the packet is sent to at least one candidate, false
672 * otherwise.
673 */
674static bool batadv_dat_forward_data(struct batadv_priv *bat_priv,
675 struct sk_buff *skb, __be32 ip,
676 unsigned short vid, int packet_subtype)
677{
678 int i;
679 bool ret = false;
680 int send_status;
681 struct batadv_neigh_node *neigh_node = NULL;
682 struct sk_buff *tmp_skb;
683 struct batadv_dat_candidate *cand;
684
685 cand = batadv_dat_select_candidates(bat_priv, ip_dst: ip, vid);
686 if (!cand)
687 goto out;
688
689 batadv_dbg(BATADV_DBG_DAT, bat_priv, "DHT_SEND for %pI4\n", &ip);
690
691 for (i = 0; i < BATADV_DAT_CANDIDATES_NUM; i++) {
692 if (cand[i].type == BATADV_DAT_CANDIDATE_NOT_FOUND)
693 continue;
694
695 neigh_node = batadv_orig_router_get(orig_node: cand[i].orig_node,
696 BATADV_IF_DEFAULT);
697 if (!neigh_node)
698 goto free_orig;
699
700 tmp_skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
701 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, skb: tmp_skb,
702 orig_node: cand[i].orig_node,
703 packet_subtype)) {
704 kfree_skb(skb: tmp_skb);
705 goto free_neigh;
706 }
707
708 send_status = batadv_send_unicast_skb(skb: tmp_skb, neigh_node);
709 if (send_status == NET_XMIT_SUCCESS) {
710 /* count the sent packet */
711 switch (packet_subtype) {
712 case BATADV_P_DAT_DHT_GET:
713 batadv_inc_counter(bat_priv,
714 BATADV_CNT_DAT_GET_TX);
715 break;
716 case BATADV_P_DAT_DHT_PUT:
717 batadv_inc_counter(bat_priv,
718 BATADV_CNT_DAT_PUT_TX);
719 break;
720 }
721
722 /* packet sent to a candidate: return true */
723 ret = true;
724 }
725free_neigh:
726 batadv_neigh_node_put(neigh_node);
727free_orig:
728 batadv_orig_node_put(orig_node: cand[i].orig_node);
729 }
730
731out:
732 kfree(objp: cand);
733 return ret;
734}
735
736/**
737 * batadv_dat_tvlv_container_update() - update the dat tvlv container after dat
738 * setting change
739 * @bat_priv: the bat priv with all the soft interface information
740 */
741static void batadv_dat_tvlv_container_update(struct batadv_priv *bat_priv)
742{
743 char dat_mode;
744
745 dat_mode = atomic_read(v: &bat_priv->distributed_arp_table);
746
747 switch (dat_mode) {
748 case 0:
749 batadv_tvlv_container_unregister(bat_priv, type: BATADV_TVLV_DAT, version: 1);
750 break;
751 case 1:
752 batadv_tvlv_container_register(bat_priv, type: BATADV_TVLV_DAT, version: 1,
753 NULL, tvlv_value_len: 0);
754 break;
755 }
756}
757
758/**
759 * batadv_dat_status_update() - update the dat tvlv container after dat
760 * setting change
761 * @net_dev: the soft interface net device
762 */
763void batadv_dat_status_update(struct net_device *net_dev)
764{
765 struct batadv_priv *bat_priv = netdev_priv(dev: net_dev);
766
767 batadv_dat_tvlv_container_update(bat_priv);
768}
769
770/**
771 * batadv_dat_tvlv_ogm_handler_v1() - process incoming dat tvlv container
772 * @bat_priv: the bat priv with all the soft interface information
773 * @orig: the orig_node of the ogm
774 * @flags: flags indicating the tvlv state (see batadv_tvlv_handler_flags)
775 * @tvlv_value: tvlv buffer containing the gateway data
776 * @tvlv_value_len: tvlv buffer length
777 */
778static void batadv_dat_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
779 struct batadv_orig_node *orig,
780 u8 flags,
781 void *tvlv_value, u16 tvlv_value_len)
782{
783 if (flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND)
784 clear_bit(nr: BATADV_ORIG_CAPA_HAS_DAT, addr: &orig->capabilities);
785 else
786 set_bit(nr: BATADV_ORIG_CAPA_HAS_DAT, addr: &orig->capabilities);
787}
788
789/**
790 * batadv_dat_hash_free() - free the local DAT hash table
791 * @bat_priv: the bat priv with all the soft interface information
792 */
793static void batadv_dat_hash_free(struct batadv_priv *bat_priv)
794{
795 if (!bat_priv->dat.hash)
796 return;
797
798 __batadv_dat_purge(bat_priv, NULL);
799
800 batadv_hash_destroy(hash: bat_priv->dat.hash);
801
802 bat_priv->dat.hash = NULL;
803}
804
805/**
806 * batadv_dat_init() - initialise the DAT internals
807 * @bat_priv: the bat priv with all the soft interface information
808 *
809 * Return: 0 in case of success, a negative error code otherwise
810 */
811int batadv_dat_init(struct batadv_priv *bat_priv)
812{
813 if (bat_priv->dat.hash)
814 return 0;
815
816 bat_priv->dat.hash = batadv_hash_new(size: 1024);
817
818 if (!bat_priv->dat.hash)
819 return -ENOMEM;
820
821 INIT_DELAYED_WORK(&bat_priv->dat.work, batadv_dat_purge);
822 batadv_dat_start_timer(bat_priv);
823
824 batadv_tvlv_handler_register(bat_priv, optr: batadv_dat_tvlv_ogm_handler_v1,
825 NULL, NULL, type: BATADV_TVLV_DAT, version: 1,
826 flags: BATADV_TVLV_HANDLER_OGM_CIFNOTFND);
827 batadv_dat_tvlv_container_update(bat_priv);
828 return 0;
829}
830
831/**
832 * batadv_dat_free() - free the DAT internals
833 * @bat_priv: the bat priv with all the soft interface information
834 */
835void batadv_dat_free(struct batadv_priv *bat_priv)
836{
837 batadv_tvlv_container_unregister(bat_priv, type: BATADV_TVLV_DAT, version: 1);
838 batadv_tvlv_handler_unregister(bat_priv, type: BATADV_TVLV_DAT, version: 1);
839
840 cancel_delayed_work_sync(dwork: &bat_priv->dat.work);
841
842 batadv_dat_hash_free(bat_priv);
843}
844
845/**
846 * batadv_dat_cache_dump_entry() - dump one entry of the DAT cache table to a
847 * netlink socket
848 * @msg: buffer for the message
849 * @portid: netlink port
850 * @cb: Control block containing additional options
851 * @dat_entry: entry to dump
852 *
853 * Return: 0 or error code.
854 */
855static int
856batadv_dat_cache_dump_entry(struct sk_buff *msg, u32 portid,
857 struct netlink_callback *cb,
858 struct batadv_dat_entry *dat_entry)
859{
860 int msecs;
861 void *hdr;
862
863 hdr = genlmsg_put(skb: msg, portid, seq: cb->nlh->nlmsg_seq,
864 family: &batadv_netlink_family, NLM_F_MULTI,
865 cmd: BATADV_CMD_GET_DAT_CACHE);
866 if (!hdr)
867 return -ENOBUFS;
868
869 genl_dump_check_consistent(cb, user_hdr: hdr);
870
871 msecs = jiffies_to_msecs(j: jiffies - dat_entry->last_update);
872
873 if (nla_put_in_addr(skb: msg, attrtype: BATADV_ATTR_DAT_CACHE_IP4ADDRESS,
874 addr: dat_entry->ip) ||
875 nla_put(skb: msg, attrtype: BATADV_ATTR_DAT_CACHE_HWADDRESS, ETH_ALEN,
876 data: dat_entry->mac_addr) ||
877 nla_put_u16(skb: msg, attrtype: BATADV_ATTR_DAT_CACHE_VID, value: dat_entry->vid) ||
878 nla_put_u32(skb: msg, attrtype: BATADV_ATTR_LAST_SEEN_MSECS, value: msecs)) {
879 genlmsg_cancel(skb: msg, hdr);
880 return -EMSGSIZE;
881 }
882
883 genlmsg_end(skb: msg, hdr);
884 return 0;
885}
886
887/**
888 * batadv_dat_cache_dump_bucket() - dump one bucket of the DAT cache table to
889 * a netlink socket
890 * @msg: buffer for the message
891 * @portid: netlink port
892 * @cb: Control block containing additional options
893 * @hash: hash to dump
894 * @bucket: bucket index to dump
895 * @idx_skip: How many entries to skip
896 *
897 * Return: 0 or error code.
898 */
899static int
900batadv_dat_cache_dump_bucket(struct sk_buff *msg, u32 portid,
901 struct netlink_callback *cb,
902 struct batadv_hashtable *hash, unsigned int bucket,
903 int *idx_skip)
904{
905 struct batadv_dat_entry *dat_entry;
906 int idx = 0;
907
908 spin_lock_bh(lock: &hash->list_locks[bucket]);
909 cb->seq = atomic_read(v: &hash->generation) << 1 | 1;
910
911 hlist_for_each_entry(dat_entry, &hash->table[bucket], hash_entry) {
912 if (idx < *idx_skip)
913 goto skip;
914
915 if (batadv_dat_cache_dump_entry(msg, portid, cb, dat_entry)) {
916 spin_unlock_bh(lock: &hash->list_locks[bucket]);
917 *idx_skip = idx;
918
919 return -EMSGSIZE;
920 }
921
922skip:
923 idx++;
924 }
925 spin_unlock_bh(lock: &hash->list_locks[bucket]);
926
927 return 0;
928}
929
930/**
931 * batadv_dat_cache_dump() - dump DAT cache table to a netlink socket
932 * @msg: buffer for the message
933 * @cb: callback structure containing arguments
934 *
935 * Return: message length.
936 */
937int batadv_dat_cache_dump(struct sk_buff *msg, struct netlink_callback *cb)
938{
939 struct batadv_hard_iface *primary_if = NULL;
940 int portid = NETLINK_CB(cb->skb).portid;
941 struct net *net = sock_net(sk: cb->skb->sk);
942 struct net_device *soft_iface;
943 struct batadv_hashtable *hash;
944 struct batadv_priv *bat_priv;
945 int bucket = cb->args[0];
946 int idx = cb->args[1];
947 int ifindex;
948 int ret = 0;
949
950 ifindex = batadv_netlink_get_ifindex(nlh: cb->nlh,
951 attrtype: BATADV_ATTR_MESH_IFINDEX);
952 if (!ifindex)
953 return -EINVAL;
954
955 soft_iface = dev_get_by_index(net, ifindex);
956 if (!soft_iface || !batadv_softif_is_valid(net_dev: soft_iface)) {
957 ret = -ENODEV;
958 goto out;
959 }
960
961 bat_priv = netdev_priv(dev: soft_iface);
962 hash = bat_priv->dat.hash;
963
964 primary_if = batadv_primary_if_get_selected(bat_priv);
965 if (!primary_if || primary_if->if_status != BATADV_IF_ACTIVE) {
966 ret = -ENOENT;
967 goto out;
968 }
969
970 while (bucket < hash->size) {
971 if (batadv_dat_cache_dump_bucket(msg, portid, cb, hash, bucket,
972 idx_skip: &idx))
973 break;
974
975 bucket++;
976 idx = 0;
977 }
978
979 cb->args[0] = bucket;
980 cb->args[1] = idx;
981
982 ret = msg->len;
983
984out:
985 batadv_hardif_put(hard_iface: primary_if);
986
987 dev_put(dev: soft_iface);
988
989 return ret;
990}
991
992/**
993 * batadv_arp_get_type() - parse an ARP packet and gets the type
994 * @bat_priv: the bat priv with all the soft interface information
995 * @skb: packet to analyse
996 * @hdr_size: size of the possible header before the ARP packet in the skb
997 *
998 * Return: the ARP type if the skb contains a valid ARP packet, 0 otherwise.
999 */
1000static u16 batadv_arp_get_type(struct batadv_priv *bat_priv,
1001 struct sk_buff *skb, int hdr_size)
1002{
1003 struct arphdr *arphdr;
1004 struct ethhdr *ethhdr;
1005 __be32 ip_src, ip_dst;
1006 u8 *hw_src, *hw_dst;
1007 u16 type = 0;
1008
1009 /* pull the ethernet header */
1010 if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN)))
1011 goto out;
1012
1013 ethhdr = (struct ethhdr *)(skb->data + hdr_size);
1014
1015 if (ethhdr->h_proto != htons(ETH_P_ARP))
1016 goto out;
1017
1018 /* pull the ARP payload */
1019 if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN +
1020 arp_hdr_len(skb->dev))))
1021 goto out;
1022
1023 arphdr = (struct arphdr *)(skb->data + hdr_size + ETH_HLEN);
1024
1025 /* check whether the ARP packet carries a valid IP information */
1026 if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
1027 goto out;
1028
1029 if (arphdr->ar_pro != htons(ETH_P_IP))
1030 goto out;
1031
1032 if (arphdr->ar_hln != ETH_ALEN)
1033 goto out;
1034
1035 if (arphdr->ar_pln != 4)
1036 goto out;
1037
1038 /* Check for bad reply/request. If the ARP message is not sane, DAT
1039 * will simply ignore it
1040 */
1041 ip_src = batadv_arp_ip_src(skb, hdr_size);
1042 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
1043 if (ipv4_is_loopback(addr: ip_src) || ipv4_is_multicast(addr: ip_src) ||
1044 ipv4_is_loopback(addr: ip_dst) || ipv4_is_multicast(addr: ip_dst) ||
1045 ipv4_is_zeronet(addr: ip_src) || ipv4_is_lbcast(addr: ip_src) ||
1046 ipv4_is_zeronet(addr: ip_dst) || ipv4_is_lbcast(addr: ip_dst))
1047 goto out;
1048
1049 hw_src = batadv_arp_hw_src(skb, hdr_size);
1050 if (is_zero_ether_addr(addr: hw_src) || is_multicast_ether_addr(addr: hw_src))
1051 goto out;
1052
1053 /* don't care about the destination MAC address in ARP requests */
1054 if (arphdr->ar_op != htons(ARPOP_REQUEST)) {
1055 hw_dst = batadv_arp_hw_dst(skb, hdr_size);
1056 if (is_zero_ether_addr(addr: hw_dst) ||
1057 is_multicast_ether_addr(addr: hw_dst))
1058 goto out;
1059 }
1060
1061 type = ntohs(arphdr->ar_op);
1062out:
1063 return type;
1064}
1065
1066/**
1067 * batadv_dat_get_vid() - extract the VLAN identifier from skb if any
1068 * @skb: the buffer containing the packet to extract the VID from
1069 * @hdr_size: the size of the batman-adv header encapsulating the packet
1070 *
1071 * Return: If the packet embedded in the skb is vlan tagged this function
1072 * returns the VID with the BATADV_VLAN_HAS_TAG flag. Otherwise BATADV_NO_FLAGS
1073 * is returned.
1074 */
1075static unsigned short batadv_dat_get_vid(struct sk_buff *skb, int *hdr_size)
1076{
1077 unsigned short vid;
1078
1079 vid = batadv_get_vid(skb, header_len: *hdr_size);
1080
1081 /* ARP parsing functions jump forward of hdr_size + ETH_HLEN.
1082 * If the header contained in the packet is a VLAN one (which is longer)
1083 * hdr_size is updated so that the functions will still skip the
1084 * correct amount of bytes.
1085 */
1086 if (vid & BATADV_VLAN_HAS_TAG)
1087 *hdr_size += VLAN_HLEN;
1088
1089 return vid;
1090}
1091
1092/**
1093 * batadv_dat_arp_create_reply() - create an ARP Reply
1094 * @bat_priv: the bat priv with all the soft interface information
1095 * @ip_src: ARP sender IP
1096 * @ip_dst: ARP target IP
1097 * @hw_src: Ethernet source and ARP sender MAC
1098 * @hw_dst: Ethernet destination and ARP target MAC
1099 * @vid: VLAN identifier (optional, set to zero otherwise)
1100 *
1101 * Creates an ARP Reply from the given values, optionally encapsulated in a
1102 * VLAN header.
1103 *
1104 * Return: An skb containing an ARP Reply.
1105 */
1106static struct sk_buff *
1107batadv_dat_arp_create_reply(struct batadv_priv *bat_priv, __be32 ip_src,
1108 __be32 ip_dst, u8 *hw_src, u8 *hw_dst,
1109 unsigned short vid)
1110{
1111 struct sk_buff *skb;
1112
1113 skb = arp_create(ARPOP_REPLY, ETH_P_ARP, dest_ip: ip_dst, dev: bat_priv->soft_iface,
1114 src_ip: ip_src, dest_hw: hw_dst, src_hw: hw_src, target_hw: hw_dst);
1115 if (!skb)
1116 return NULL;
1117
1118 skb_reset_mac_header(skb);
1119
1120 if (vid & BATADV_VLAN_HAS_TAG)
1121 skb = vlan_insert_tag(skb, htons(ETH_P_8021Q),
1122 vlan_tci: vid & VLAN_VID_MASK);
1123
1124 return skb;
1125}
1126
1127/**
1128 * batadv_dat_snoop_outgoing_arp_request() - snoop the ARP request and try to
1129 * answer using DAT
1130 * @bat_priv: the bat priv with all the soft interface information
1131 * @skb: packet to check
1132 *
1133 * Return: true if the message has been sent to the dht candidates, false
1134 * otherwise. In case of a positive return value the message has to be enqueued
1135 * to permit the fallback.
1136 */
1137bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv,
1138 struct sk_buff *skb)
1139{
1140 u16 type = 0;
1141 __be32 ip_dst, ip_src;
1142 u8 *hw_src;
1143 bool ret = false;
1144 struct batadv_dat_entry *dat_entry = NULL;
1145 struct sk_buff *skb_new;
1146 struct net_device *soft_iface = bat_priv->soft_iface;
1147 int hdr_size = 0;
1148 unsigned short vid;
1149
1150 if (!atomic_read(v: &bat_priv->distributed_arp_table))
1151 goto out;
1152
1153 vid = batadv_dat_get_vid(skb, hdr_size: &hdr_size);
1154
1155 type = batadv_arp_get_type(bat_priv, skb, hdr_size);
1156 /* If the node gets an ARP_REQUEST it has to send a DHT_GET unicast
1157 * message to the selected DHT candidates
1158 */
1159 if (type != ARPOP_REQUEST)
1160 goto out;
1161
1162 batadv_dbg_arp(bat_priv, skb, hdr_size, msg: "Parsing outgoing ARP REQUEST");
1163
1164 ip_src = batadv_arp_ip_src(skb, hdr_size);
1165 hw_src = batadv_arp_hw_src(skb, hdr_size);
1166 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
1167
1168 batadv_dat_entry_add(bat_priv, ip: ip_src, mac_addr: hw_src, vid);
1169
1170 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip: ip_dst, vid);
1171 if (dat_entry) {
1172 /* If the ARP request is destined for a local client the local
1173 * client will answer itself. DAT would only generate a
1174 * duplicate packet.
1175 *
1176 * Moreover, if the soft-interface is enslaved into a bridge, an
1177 * additional DAT answer may trigger kernel warnings about
1178 * a packet coming from the wrong port.
1179 */
1180 if (batadv_is_my_client(bat_priv, addr: dat_entry->mac_addr, vid)) {
1181 ret = true;
1182 goto out;
1183 }
1184
1185 /* If BLA is enabled, only send ARP replies if we have claimed
1186 * the destination for the ARP request or if no one else of
1187 * the backbone gws belonging to our backbone has claimed the
1188 * destination.
1189 */
1190 if (!batadv_bla_check_claim(bat_priv,
1191 addr: dat_entry->mac_addr, vid)) {
1192 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1193 "Device %pM claimed by another backbone gw. Don't send ARP reply!",
1194 dat_entry->mac_addr);
1195 ret = true;
1196 goto out;
1197 }
1198
1199 skb_new = batadv_dat_arp_create_reply(bat_priv, ip_src: ip_dst, ip_dst: ip_src,
1200 hw_src: dat_entry->mac_addr,
1201 hw_dst: hw_src, vid);
1202 if (!skb_new)
1203 goto out;
1204
1205 skb_new->protocol = eth_type_trans(skb: skb_new, dev: soft_iface);
1206
1207 batadv_inc_counter(bat_priv, BATADV_CNT_RX);
1208 batadv_add_counter(bat_priv, idx: BATADV_CNT_RX_BYTES,
1209 count: skb->len + ETH_HLEN + hdr_size);
1210
1211 netif_rx(skb: skb_new);
1212 batadv_dbg(BATADV_DBG_DAT, bat_priv, "ARP request replied locally\n");
1213 ret = true;
1214 } else {
1215 /* Send the request to the DHT */
1216 ret = batadv_dat_forward_data(bat_priv, skb, ip: ip_dst, vid,
1217 packet_subtype: BATADV_P_DAT_DHT_GET);
1218 }
1219out:
1220 batadv_dat_entry_put(dat_entry);
1221 return ret;
1222}
1223
1224/**
1225 * batadv_dat_snoop_incoming_arp_request() - snoop the ARP request and try to
1226 * answer using the local DAT storage
1227 * @bat_priv: the bat priv with all the soft interface information
1228 * @skb: packet to check
1229 * @hdr_size: size of the encapsulation header
1230 *
1231 * Return: true if the request has been answered, false otherwise.
1232 */
1233bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv,
1234 struct sk_buff *skb, int hdr_size)
1235{
1236 u16 type;
1237 __be32 ip_src, ip_dst;
1238 u8 *hw_src;
1239 struct sk_buff *skb_new;
1240 struct batadv_dat_entry *dat_entry = NULL;
1241 bool ret = false;
1242 unsigned short vid;
1243 int err;
1244
1245 if (!atomic_read(v: &bat_priv->distributed_arp_table))
1246 goto out;
1247
1248 vid = batadv_dat_get_vid(skb, hdr_size: &hdr_size);
1249
1250 type = batadv_arp_get_type(bat_priv, skb, hdr_size);
1251 if (type != ARPOP_REQUEST)
1252 goto out;
1253
1254 hw_src = batadv_arp_hw_src(skb, hdr_size);
1255 ip_src = batadv_arp_ip_src(skb, hdr_size);
1256 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
1257
1258 batadv_dbg_arp(bat_priv, skb, hdr_size, msg: "Parsing incoming ARP REQUEST");
1259
1260 batadv_dat_entry_add(bat_priv, ip: ip_src, mac_addr: hw_src, vid);
1261
1262 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip: ip_dst, vid);
1263 if (!dat_entry)
1264 goto out;
1265
1266 skb_new = batadv_dat_arp_create_reply(bat_priv, ip_src: ip_dst, ip_dst: ip_src,
1267 hw_src: dat_entry->mac_addr, hw_dst: hw_src, vid);
1268 if (!skb_new)
1269 goto out;
1270
1271 /* To preserve backwards compatibility, the node has choose the outgoing
1272 * format based on the incoming request packet type. The assumption is
1273 * that a node not using the 4addr packet format doesn't support it.
1274 */
1275 if (hdr_size == sizeof(struct batadv_unicast_4addr_packet))
1276 err = batadv_send_skb_via_tt_4addr(bat_priv, skb: skb_new,
1277 packet_subtype: BATADV_P_DAT_CACHE_REPLY,
1278 NULL, vid);
1279 else
1280 err = batadv_send_skb_via_tt(bat_priv, skb: skb_new, NULL, vid);
1281
1282 if (err != NET_XMIT_DROP) {
1283 batadv_inc_counter(bat_priv, BATADV_CNT_DAT_CACHED_REPLY_TX);
1284 ret = true;
1285 }
1286out:
1287 batadv_dat_entry_put(dat_entry);
1288 if (ret)
1289 kfree_skb(skb);
1290 return ret;
1291}
1292
1293/**
1294 * batadv_dat_snoop_outgoing_arp_reply() - snoop the ARP reply and fill the DHT
1295 * @bat_priv: the bat priv with all the soft interface information
1296 * @skb: packet to check
1297 */
1298void batadv_dat_snoop_outgoing_arp_reply(struct batadv_priv *bat_priv,
1299 struct sk_buff *skb)
1300{
1301 u16 type;
1302 __be32 ip_src, ip_dst;
1303 u8 *hw_src, *hw_dst;
1304 int hdr_size = 0;
1305 unsigned short vid;
1306
1307 if (!atomic_read(v: &bat_priv->distributed_arp_table))
1308 return;
1309
1310 vid = batadv_dat_get_vid(skb, hdr_size: &hdr_size);
1311
1312 type = batadv_arp_get_type(bat_priv, skb, hdr_size);
1313 if (type != ARPOP_REPLY)
1314 return;
1315
1316 batadv_dbg_arp(bat_priv, skb, hdr_size, msg: "Parsing outgoing ARP REPLY");
1317
1318 hw_src = batadv_arp_hw_src(skb, hdr_size);
1319 ip_src = batadv_arp_ip_src(skb, hdr_size);
1320 hw_dst = batadv_arp_hw_dst(skb, hdr_size);
1321 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
1322
1323 batadv_dat_entry_add(bat_priv, ip: ip_src, mac_addr: hw_src, vid);
1324 batadv_dat_entry_add(bat_priv, ip: ip_dst, mac_addr: hw_dst, vid);
1325
1326 /* Send the ARP reply to the candidates for both the IP addresses that
1327 * the node obtained from the ARP reply
1328 */
1329 batadv_dat_forward_data(bat_priv, skb, ip: ip_src, vid,
1330 packet_subtype: BATADV_P_DAT_DHT_PUT);
1331 batadv_dat_forward_data(bat_priv, skb, ip: ip_dst, vid,
1332 packet_subtype: BATADV_P_DAT_DHT_PUT);
1333}
1334
1335/**
1336 * batadv_dat_snoop_incoming_arp_reply() - snoop the ARP reply and fill the
1337 * local DAT storage only
1338 * @bat_priv: the bat priv with all the soft interface information
1339 * @skb: packet to check
1340 * @hdr_size: size of the encapsulation header
1341 *
1342 * Return: true if the packet was snooped and consumed by DAT. False if the
1343 * packet has to be delivered to the interface
1344 */
1345bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv,
1346 struct sk_buff *skb, int hdr_size)
1347{
1348 struct batadv_dat_entry *dat_entry = NULL;
1349 u16 type;
1350 __be32 ip_src, ip_dst;
1351 u8 *hw_src, *hw_dst;
1352 bool dropped = false;
1353 unsigned short vid;
1354
1355 if (!atomic_read(v: &bat_priv->distributed_arp_table))
1356 goto out;
1357
1358 vid = batadv_dat_get_vid(skb, hdr_size: &hdr_size);
1359
1360 type = batadv_arp_get_type(bat_priv, skb, hdr_size);
1361 if (type != ARPOP_REPLY)
1362 goto out;
1363
1364 batadv_dbg_arp(bat_priv, skb, hdr_size, msg: "Parsing incoming ARP REPLY");
1365
1366 hw_src = batadv_arp_hw_src(skb, hdr_size);
1367 ip_src = batadv_arp_ip_src(skb, hdr_size);
1368 hw_dst = batadv_arp_hw_dst(skb, hdr_size);
1369 ip_dst = batadv_arp_ip_dst(skb, hdr_size);
1370
1371 /* If ip_dst is already in cache and has the right mac address,
1372 * drop this frame if this ARP reply is destined for us because it's
1373 * most probably an ARP reply generated by another node of the DHT.
1374 * We have most probably received already a reply earlier. Delivering
1375 * this frame would lead to doubled receive of an ARP reply.
1376 */
1377 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip: ip_src, vid);
1378 if (dat_entry && batadv_compare_eth(data1: hw_src, data2: dat_entry->mac_addr)) {
1379 batadv_dbg(BATADV_DBG_DAT, bat_priv, "Doubled ARP reply removed: ARP MSG = [src: %pM-%pI4 dst: %pM-%pI4]; dat_entry: %pM-%pI4\n",
1380 hw_src, &ip_src, hw_dst, &ip_dst,
1381 dat_entry->mac_addr, &dat_entry->ip);
1382 dropped = true;
1383 }
1384
1385 /* Update our internal cache with both the IP addresses the node got
1386 * within the ARP reply
1387 */
1388 batadv_dat_entry_add(bat_priv, ip: ip_src, mac_addr: hw_src, vid);
1389 batadv_dat_entry_add(bat_priv, ip: ip_dst, mac_addr: hw_dst, vid);
1390
1391 if (dropped)
1392 goto out;
1393
1394 /* If BLA is enabled, only forward ARP replies if we have claimed the
1395 * source of the ARP reply or if no one else of the same backbone has
1396 * already claimed that client. This prevents that different gateways
1397 * to the same backbone all forward the ARP reply leading to multiple
1398 * replies in the backbone.
1399 */
1400 if (!batadv_bla_check_claim(bat_priv, addr: hw_src, vid)) {
1401 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1402 "Device %pM claimed by another backbone gw. Drop ARP reply.\n",
1403 hw_src);
1404 dropped = true;
1405 goto out;
1406 }
1407
1408 /* if this REPLY is directed to a client of mine, let's deliver the
1409 * packet to the interface
1410 */
1411 dropped = !batadv_is_my_client(bat_priv, addr: hw_dst, vid);
1412
1413 /* if this REPLY is sent on behalf of a client of mine, let's drop the
1414 * packet because the client will reply by itself
1415 */
1416 dropped |= batadv_is_my_client(bat_priv, addr: hw_src, vid);
1417out:
1418 if (dropped)
1419 kfree_skb(skb);
1420 batadv_dat_entry_put(dat_entry);
1421 /* if dropped == false -> deliver to the interface */
1422 return dropped;
1423}
1424
1425/**
1426 * batadv_dat_check_dhcp_ipudp() - check skb for IP+UDP headers valid for DHCP
1427 * @skb: the packet to check
1428 * @ip_src: a buffer to store the IPv4 source address in
1429 *
1430 * Checks whether the given skb has an IP and UDP header valid for a DHCP
1431 * message from a DHCP server. And if so, stores the IPv4 source address in
1432 * the provided buffer.
1433 *
1434 * Return: True if valid, false otherwise.
1435 */
1436static bool
1437batadv_dat_check_dhcp_ipudp(struct sk_buff *skb, __be32 *ip_src)
1438{
1439 unsigned int offset = skb_network_offset(skb);
1440 struct udphdr *udphdr, _udphdr;
1441 struct iphdr *iphdr, _iphdr;
1442
1443 iphdr = skb_header_pointer(skb, offset, len: sizeof(_iphdr), buffer: &_iphdr);
1444 if (!iphdr || iphdr->version != 4 || iphdr->ihl * 4 < sizeof(_iphdr))
1445 return false;
1446
1447 if (iphdr->protocol != IPPROTO_UDP)
1448 return false;
1449
1450 offset += iphdr->ihl * 4;
1451 skb_set_transport_header(skb, offset);
1452
1453 udphdr = skb_header_pointer(skb, offset, len: sizeof(_udphdr), buffer: &_udphdr);
1454 if (!udphdr || udphdr->source != htons(67))
1455 return false;
1456
1457 *ip_src = get_unaligned(&iphdr->saddr);
1458
1459 return true;
1460}
1461
1462/**
1463 * batadv_dat_check_dhcp() - examine packet for valid DHCP message
1464 * @skb: the packet to check
1465 * @proto: ethernet protocol hint (behind a potential vlan)
1466 * @ip_src: a buffer to store the IPv4 source address in
1467 *
1468 * Checks whether the given skb is a valid DHCP packet. And if so, stores the
1469 * IPv4 source address in the provided buffer.
1470 *
1471 * Caller needs to ensure that the skb network header is set correctly.
1472 *
1473 * Return: If skb is a valid DHCP packet, then returns its op code
1474 * (e.g. BOOTREPLY vs. BOOTREQUEST). Otherwise returns -EINVAL.
1475 */
1476static int
1477batadv_dat_check_dhcp(struct sk_buff *skb, __be16 proto, __be32 *ip_src)
1478{
1479 __be32 *magic, _magic;
1480 unsigned int offset;
1481 struct {
1482 __u8 op;
1483 __u8 htype;
1484 __u8 hlen;
1485 __u8 hops;
1486 } *dhcp_h, _dhcp_h;
1487
1488 if (proto != htons(ETH_P_IP))
1489 return -EINVAL;
1490
1491 if (!batadv_dat_check_dhcp_ipudp(skb, ip_src))
1492 return -EINVAL;
1493
1494 offset = skb_transport_offset(skb) + sizeof(struct udphdr);
1495 if (skb->len < offset + sizeof(struct batadv_dhcp_packet))
1496 return -EINVAL;
1497
1498 dhcp_h = skb_header_pointer(skb, offset, len: sizeof(_dhcp_h), buffer: &_dhcp_h);
1499 if (!dhcp_h || dhcp_h->htype != BATADV_HTYPE_ETHERNET ||
1500 dhcp_h->hlen != ETH_ALEN)
1501 return -EINVAL;
1502
1503 offset += offsetof(struct batadv_dhcp_packet, magic);
1504
1505 magic = skb_header_pointer(skb, offset, len: sizeof(_magic), buffer: &_magic);
1506 if (!magic || get_unaligned(magic) != htonl(BATADV_DHCP_MAGIC))
1507 return -EINVAL;
1508
1509 return dhcp_h->op;
1510}
1511
1512/**
1513 * batadv_dat_get_dhcp_message_type() - get message type of a DHCP packet
1514 * @skb: the DHCP packet to parse
1515 *
1516 * Iterates over the DHCP options of the given DHCP packet to find a
1517 * DHCP Message Type option and parse it.
1518 *
1519 * Caller needs to ensure that the given skb is a valid DHCP packet and
1520 * that the skb transport header is set correctly.
1521 *
1522 * Return: The found DHCP message type value, if found. -EINVAL otherwise.
1523 */
1524static int batadv_dat_get_dhcp_message_type(struct sk_buff *skb)
1525{
1526 unsigned int offset = skb_transport_offset(skb) + sizeof(struct udphdr);
1527 u8 *type, _type;
1528 struct {
1529 u8 type;
1530 u8 len;
1531 } *tl, _tl;
1532
1533 offset += sizeof(struct batadv_dhcp_packet);
1534
1535 while ((tl = skb_header_pointer(skb, offset, len: sizeof(_tl), buffer: &_tl))) {
1536 if (tl->type == BATADV_DHCP_OPT_MSG_TYPE)
1537 break;
1538
1539 if (tl->type == BATADV_DHCP_OPT_END)
1540 break;
1541
1542 if (tl->type == BATADV_DHCP_OPT_PAD)
1543 offset++;
1544 else
1545 offset += tl->len + sizeof(_tl);
1546 }
1547
1548 /* Option Overload Code not supported */
1549 if (!tl || tl->type != BATADV_DHCP_OPT_MSG_TYPE ||
1550 tl->len != sizeof(_type))
1551 return -EINVAL;
1552
1553 offset += sizeof(_tl);
1554
1555 type = skb_header_pointer(skb, offset, len: sizeof(_type), buffer: &_type);
1556 if (!type)
1557 return -EINVAL;
1558
1559 return *type;
1560}
1561
1562/**
1563 * batadv_dat_dhcp_get_yiaddr() - get yiaddr from a DHCP packet
1564 * @skb: the DHCP packet to parse
1565 * @buf: a buffer to store the yiaddr in
1566 *
1567 * Caller needs to ensure that the given skb is a valid DHCP packet and
1568 * that the skb transport header is set correctly.
1569 *
1570 * Return: True on success, false otherwise.
1571 */
1572static bool batadv_dat_dhcp_get_yiaddr(struct sk_buff *skb, __be32 *buf)
1573{
1574 unsigned int offset = skb_transport_offset(skb) + sizeof(struct udphdr);
1575 __be32 *yiaddr;
1576
1577 offset += offsetof(struct batadv_dhcp_packet, yiaddr);
1578 yiaddr = skb_header_pointer(skb, offset, BATADV_DHCP_YIADDR_LEN, buffer: buf);
1579
1580 if (!yiaddr)
1581 return false;
1582
1583 if (yiaddr != buf)
1584 *buf = get_unaligned(yiaddr);
1585
1586 return true;
1587}
1588
1589/**
1590 * batadv_dat_get_dhcp_chaddr() - get chaddr from a DHCP packet
1591 * @skb: the DHCP packet to parse
1592 * @buf: a buffer to store the chaddr in
1593 *
1594 * Caller needs to ensure that the given skb is a valid DHCP packet and
1595 * that the skb transport header is set correctly.
1596 *
1597 * Return: True on success, false otherwise
1598 */
1599static bool batadv_dat_get_dhcp_chaddr(struct sk_buff *skb, u8 *buf)
1600{
1601 unsigned int offset = skb_transport_offset(skb) + sizeof(struct udphdr);
1602 u8 *chaddr;
1603
1604 offset += offsetof(struct batadv_dhcp_packet, chaddr);
1605 chaddr = skb_header_pointer(skb, offset, BATADV_DHCP_CHADDR_LEN, buffer: buf);
1606
1607 if (!chaddr)
1608 return false;
1609
1610 if (chaddr != buf)
1611 memcpy(buf, chaddr, BATADV_DHCP_CHADDR_LEN);
1612
1613 return true;
1614}
1615
1616/**
1617 * batadv_dat_put_dhcp() - puts addresses from a DHCP packet into the DHT and
1618 * DAT cache
1619 * @bat_priv: the bat priv with all the soft interface information
1620 * @chaddr: the DHCP client MAC address
1621 * @yiaddr: the DHCP client IP address
1622 * @hw_dst: the DHCP server MAC address
1623 * @ip_dst: the DHCP server IP address
1624 * @vid: VLAN identifier
1625 *
1626 * Adds given MAC/IP pairs to the local DAT cache and propagates them further
1627 * into the DHT.
1628 *
1629 * For the DHT propagation, client MAC + IP will appear as the ARP Reply
1630 * transmitter (and hw_dst/ip_dst as the target).
1631 */
1632static void batadv_dat_put_dhcp(struct batadv_priv *bat_priv, u8 *chaddr,
1633 __be32 yiaddr, u8 *hw_dst, __be32 ip_dst,
1634 unsigned short vid)
1635{
1636 struct sk_buff *skb;
1637
1638 skb = batadv_dat_arp_create_reply(bat_priv, ip_src: yiaddr, ip_dst, hw_src: chaddr,
1639 hw_dst, vid);
1640 if (!skb)
1641 return;
1642
1643 skb_set_network_header(skb, ETH_HLEN);
1644
1645 batadv_dat_entry_add(bat_priv, ip: yiaddr, mac_addr: chaddr, vid);
1646 batadv_dat_entry_add(bat_priv, ip: ip_dst, mac_addr: hw_dst, vid);
1647
1648 batadv_dat_forward_data(bat_priv, skb, ip: yiaddr, vid,
1649 packet_subtype: BATADV_P_DAT_DHT_PUT);
1650 batadv_dat_forward_data(bat_priv, skb, ip: ip_dst, vid,
1651 packet_subtype: BATADV_P_DAT_DHT_PUT);
1652
1653 consume_skb(skb);
1654
1655 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1656 "Snooped from outgoing DHCPACK (server address): %pI4, %pM (vid: %i)\n",
1657 &ip_dst, hw_dst, batadv_print_vid(vid));
1658 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1659 "Snooped from outgoing DHCPACK (client address): %pI4, %pM (vid: %i)\n",
1660 &yiaddr, chaddr, batadv_print_vid(vid));
1661}
1662
1663/**
1664 * batadv_dat_check_dhcp_ack() - examine packet for valid DHCP message
1665 * @skb: the packet to check
1666 * @proto: ethernet protocol hint (behind a potential vlan)
1667 * @ip_src: a buffer to store the IPv4 source address in
1668 * @chaddr: a buffer to store the DHCP Client Hardware Address in
1669 * @yiaddr: a buffer to store the DHCP Your IP Address in
1670 *
1671 * Checks whether the given skb is a valid DHCPACK. And if so, stores the
1672 * IPv4 server source address (ip_src), client MAC address (chaddr) and client
1673 * IPv4 address (yiaddr) in the provided buffers.
1674 *
1675 * Caller needs to ensure that the skb network header is set correctly.
1676 *
1677 * Return: True if the skb is a valid DHCPACK. False otherwise.
1678 */
1679static bool
1680batadv_dat_check_dhcp_ack(struct sk_buff *skb, __be16 proto, __be32 *ip_src,
1681 u8 *chaddr, __be32 *yiaddr)
1682{
1683 int type;
1684
1685 type = batadv_dat_check_dhcp(skb, proto, ip_src);
1686 if (type != BATADV_BOOTREPLY)
1687 return false;
1688
1689 type = batadv_dat_get_dhcp_message_type(skb);
1690 if (type != BATADV_DHCPACK)
1691 return false;
1692
1693 if (!batadv_dat_dhcp_get_yiaddr(skb, buf: yiaddr))
1694 return false;
1695
1696 if (!batadv_dat_get_dhcp_chaddr(skb, buf: chaddr))
1697 return false;
1698
1699 return true;
1700}
1701
1702/**
1703 * batadv_dat_snoop_outgoing_dhcp_ack() - snoop DHCPACK and fill DAT with it
1704 * @bat_priv: the bat priv with all the soft interface information
1705 * @skb: the packet to snoop
1706 * @proto: ethernet protocol hint (behind a potential vlan)
1707 * @vid: VLAN identifier
1708 *
1709 * This function first checks whether the given skb is a valid DHCPACK. If
1710 * so then its source MAC and IP as well as its DHCP Client Hardware Address
1711 * field and DHCP Your IP Address field are added to the local DAT cache and
1712 * propagated into the DHT.
1713 *
1714 * Caller needs to ensure that the skb mac and network headers are set
1715 * correctly.
1716 */
1717void batadv_dat_snoop_outgoing_dhcp_ack(struct batadv_priv *bat_priv,
1718 struct sk_buff *skb,
1719 __be16 proto,
1720 unsigned short vid)
1721{
1722 u8 chaddr[BATADV_DHCP_CHADDR_LEN];
1723 __be32 ip_src, yiaddr;
1724
1725 if (!atomic_read(v: &bat_priv->distributed_arp_table))
1726 return;
1727
1728 if (!batadv_dat_check_dhcp_ack(skb, proto, ip_src: &ip_src, chaddr, yiaddr: &yiaddr))
1729 return;
1730
1731 batadv_dat_put_dhcp(bat_priv, chaddr, yiaddr, hw_dst: eth_hdr(skb)->h_source,
1732 ip_dst: ip_src, vid);
1733}
1734
1735/**
1736 * batadv_dat_snoop_incoming_dhcp_ack() - snoop DHCPACK and fill DAT cache
1737 * @bat_priv: the bat priv with all the soft interface information
1738 * @skb: the packet to snoop
1739 * @hdr_size: header size, up to the tail of the batman-adv header
1740 *
1741 * This function first checks whether the given skb is a valid DHCPACK. If
1742 * so then its source MAC and IP as well as its DHCP Client Hardware Address
1743 * field and DHCP Your IP Address field are added to the local DAT cache.
1744 */
1745void batadv_dat_snoop_incoming_dhcp_ack(struct batadv_priv *bat_priv,
1746 struct sk_buff *skb, int hdr_size)
1747{
1748 u8 chaddr[BATADV_DHCP_CHADDR_LEN];
1749 struct ethhdr *ethhdr;
1750 __be32 ip_src, yiaddr;
1751 unsigned short vid;
1752 __be16 proto;
1753 u8 *hw_src;
1754
1755 if (!atomic_read(v: &bat_priv->distributed_arp_table))
1756 return;
1757
1758 if (unlikely(!pskb_may_pull(skb, hdr_size + ETH_HLEN)))
1759 return;
1760
1761 ethhdr = (struct ethhdr *)(skb->data + hdr_size);
1762 skb_set_network_header(skb, offset: hdr_size + ETH_HLEN);
1763 proto = ethhdr->h_proto;
1764
1765 if (!batadv_dat_check_dhcp_ack(skb, proto, ip_src: &ip_src, chaddr, yiaddr: &yiaddr))
1766 return;
1767
1768 hw_src = ethhdr->h_source;
1769 vid = batadv_dat_get_vid(skb, hdr_size: &hdr_size);
1770
1771 batadv_dat_entry_add(bat_priv, ip: yiaddr, mac_addr: chaddr, vid);
1772 batadv_dat_entry_add(bat_priv, ip: ip_src, mac_addr: hw_src, vid);
1773
1774 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1775 "Snooped from incoming DHCPACK (server address): %pI4, %pM (vid: %i)\n",
1776 &ip_src, hw_src, batadv_print_vid(vid));
1777 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1778 "Snooped from incoming DHCPACK (client address): %pI4, %pM (vid: %i)\n",
1779 &yiaddr, chaddr, batadv_print_vid(vid));
1780}
1781
1782/**
1783 * batadv_dat_drop_broadcast_packet() - check if an ARP request has to be
1784 * dropped (because the node has already obtained the reply via DAT) or not
1785 * @bat_priv: the bat priv with all the soft interface information
1786 * @forw_packet: the broadcast packet
1787 *
1788 * Return: true if the node can drop the packet, false otherwise.
1789 */
1790bool batadv_dat_drop_broadcast_packet(struct batadv_priv *bat_priv,
1791 struct batadv_forw_packet *forw_packet)
1792{
1793 u16 type;
1794 __be32 ip_dst;
1795 struct batadv_dat_entry *dat_entry = NULL;
1796 bool ret = false;
1797 int hdr_size = sizeof(struct batadv_bcast_packet);
1798 unsigned short vid;
1799
1800 if (!atomic_read(v: &bat_priv->distributed_arp_table))
1801 goto out;
1802
1803 /* If this packet is an ARP_REQUEST and the node already has the
1804 * information that it is going to ask, then the packet can be dropped
1805 */
1806 if (batadv_forw_packet_is_rebroadcast(forw_packet))
1807 goto out;
1808
1809 vid = batadv_dat_get_vid(skb: forw_packet->skb, hdr_size: &hdr_size);
1810
1811 type = batadv_arp_get_type(bat_priv, skb: forw_packet->skb, hdr_size);
1812 if (type != ARPOP_REQUEST)
1813 goto out;
1814
1815 ip_dst = batadv_arp_ip_dst(skb: forw_packet->skb, hdr_size);
1816 dat_entry = batadv_dat_entry_hash_find(bat_priv, ip: ip_dst, vid);
1817 /* check if the node already got this entry */
1818 if (!dat_entry) {
1819 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1820 "ARP Request for %pI4: fallback\n", &ip_dst);
1821 goto out;
1822 }
1823
1824 batadv_dbg(BATADV_DBG_DAT, bat_priv,
1825 "ARP Request for %pI4: fallback prevented\n", &ip_dst);
1826 ret = true;
1827
1828out:
1829 batadv_dat_entry_put(dat_entry);
1830 return ret;
1831}
1832

source code of linux/net/batman-adv/distributed-arp-table.c