1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (C) B.A.T.M.A.N. contributors:
3 *
4 * Marek Lindner, Simon Wunderlich
5 */
6
7#include "routing.h"
8#include "main.h"
9
10#include <linux/atomic.h>
11#include <linux/byteorder/generic.h>
12#include <linux/compiler.h>
13#include <linux/errno.h>
14#include <linux/etherdevice.h>
15#include <linux/if_ether.h>
16#include <linux/jiffies.h>
17#include <linux/kref.h>
18#include <linux/netdevice.h>
19#include <linux/printk.h>
20#include <linux/rculist.h>
21#include <linux/rcupdate.h>
22#include <linux/skbuff.h>
23#include <linux/spinlock.h>
24#include <linux/stddef.h>
25#include <uapi/linux/batadv_packet.h>
26
27#include "bitarray.h"
28#include "bridge_loop_avoidance.h"
29#include "distributed-arp-table.h"
30#include "fragmentation.h"
31#include "hard-interface.h"
32#include "log.h"
33#include "network-coding.h"
34#include "originator.h"
35#include "send.h"
36#include "soft-interface.h"
37#include "tp_meter.h"
38#include "translation-table.h"
39#include "tvlv.h"
40
41static int batadv_route_unicast_packet(struct sk_buff *skb,
42 struct batadv_hard_iface *recv_if);
43
44/**
45 * _batadv_update_route() - set the router for this originator
46 * @bat_priv: the bat priv with all the soft interface information
47 * @orig_node: orig node which is to be configured
48 * @recv_if: the receive interface for which this route is set
49 * @neigh_node: neighbor which should be the next router
50 *
51 * This function does not perform any error checks
52 */
53static void _batadv_update_route(struct batadv_priv *bat_priv,
54 struct batadv_orig_node *orig_node,
55 struct batadv_hard_iface *recv_if,
56 struct batadv_neigh_node *neigh_node)
57{
58 struct batadv_orig_ifinfo *orig_ifinfo;
59 struct batadv_neigh_node *curr_router;
60
61 orig_ifinfo = batadv_orig_ifinfo_get(orig_node, if_outgoing: recv_if);
62 if (!orig_ifinfo)
63 return;
64
65 spin_lock_bh(lock: &orig_node->neigh_list_lock);
66 /* curr_router used earlier may not be the current orig_ifinfo->router
67 * anymore because it was dereferenced outside of the neigh_list_lock
68 * protected region. After the new best neighbor has replace the current
69 * best neighbor the reference counter needs to decrease. Consequently,
70 * the code needs to ensure the curr_router variable contains a pointer
71 * to the replaced best neighbor.
72 */
73
74 /* increase refcount of new best neighbor */
75 if (neigh_node)
76 kref_get(kref: &neigh_node->refcount);
77
78 curr_router = rcu_replace_pointer(orig_ifinfo->router, neigh_node,
79 true);
80 spin_unlock_bh(lock: &orig_node->neigh_list_lock);
81 batadv_orig_ifinfo_put(orig_ifinfo);
82
83 /* route deleted */
84 if (curr_router && !neigh_node) {
85 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
86 "Deleting route towards: %pM\n", orig_node->orig);
87 batadv_tt_global_del_orig(bat_priv, orig_node, match_vid: -1,
88 message: "Deleted route towards originator");
89
90 /* route added */
91 } else if (!curr_router && neigh_node) {
92 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
93 "Adding route towards: %pM (via %pM)\n",
94 orig_node->orig, neigh_node->addr);
95 /* route changed */
96 } else if (neigh_node && curr_router) {
97 batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
98 "Changing route towards: %pM (now via %pM - was via %pM)\n",
99 orig_node->orig, neigh_node->addr,
100 curr_router->addr);
101 }
102
103 /* decrease refcount of previous best neighbor */
104 batadv_neigh_node_put(neigh_node: curr_router);
105}
106
107/**
108 * batadv_update_route() - set the router for this originator
109 * @bat_priv: the bat priv with all the soft interface information
110 * @orig_node: orig node which is to be configured
111 * @recv_if: the receive interface for which this route is set
112 * @neigh_node: neighbor which should be the next router
113 */
114void batadv_update_route(struct batadv_priv *bat_priv,
115 struct batadv_orig_node *orig_node,
116 struct batadv_hard_iface *recv_if,
117 struct batadv_neigh_node *neigh_node)
118{
119 struct batadv_neigh_node *router = NULL;
120
121 if (!orig_node)
122 goto out;
123
124 router = batadv_orig_router_get(orig_node, if_outgoing: recv_if);
125
126 if (router != neigh_node)
127 _batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
128
129out:
130 batadv_neigh_node_put(neigh_node: router);
131}
132
133/**
134 * batadv_window_protected() - checks whether the host restarted and is in the
135 * protection time.
136 * @bat_priv: the bat priv with all the soft interface information
137 * @seq_num_diff: difference between the current/received sequence number and
138 * the last sequence number
139 * @seq_old_max_diff: maximum age of sequence number not considered as restart
140 * @last_reset: jiffies timestamp of the last reset, will be updated when reset
141 * is detected
142 * @protection_started: is set to true if the protection window was started,
143 * doesn't change otherwise.
144 *
145 * Return:
146 * false if the packet is to be accepted.
147 * true if the packet is to be ignored.
148 */
149bool batadv_window_protected(struct batadv_priv *bat_priv, s32 seq_num_diff,
150 s32 seq_old_max_diff, unsigned long *last_reset,
151 bool *protection_started)
152{
153 if (seq_num_diff <= -seq_old_max_diff ||
154 seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
155 if (!batadv_has_timed_out(timestamp: *last_reset,
156 BATADV_RESET_PROTECTION_MS))
157 return true;
158
159 *last_reset = jiffies;
160 if (protection_started)
161 *protection_started = true;
162 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
163 "old packet received, start protection\n");
164 }
165
166 return false;
167}
168
169/**
170 * batadv_check_management_packet() - Check preconditions for management packets
171 * @skb: incoming packet buffer
172 * @hard_iface: incoming hard interface
173 * @header_len: minimal header length of packet type
174 *
175 * Return: true when management preconditions are met, false otherwise
176 */
177bool batadv_check_management_packet(struct sk_buff *skb,
178 struct batadv_hard_iface *hard_iface,
179 int header_len)
180{
181 struct ethhdr *ethhdr;
182
183 /* drop packet if it has not necessary minimum size */
184 if (unlikely(!pskb_may_pull(skb, header_len)))
185 return false;
186
187 ethhdr = eth_hdr(skb);
188
189 /* packet with broadcast indication but unicast recipient */
190 if (!is_broadcast_ether_addr(addr: ethhdr->h_dest))
191 return false;
192
193 /* packet with invalid sender address */
194 if (!is_valid_ether_addr(addr: ethhdr->h_source))
195 return false;
196
197 /* create a copy of the skb, if needed, to modify it. */
198 if (skb_cow(skb, headroom: 0) < 0)
199 return false;
200
201 /* keep skb linear */
202 if (skb_linearize(skb) < 0)
203 return false;
204
205 return true;
206}
207
208/**
209 * batadv_recv_my_icmp_packet() - receive an icmp packet locally
210 * @bat_priv: the bat priv with all the soft interface information
211 * @skb: icmp packet to process
212 *
213 * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
214 * otherwise.
215 */
216static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
217 struct sk_buff *skb)
218{
219 struct batadv_hard_iface *primary_if = NULL;
220 struct batadv_orig_node *orig_node = NULL;
221 struct batadv_icmp_header *icmph;
222 int res, ret = NET_RX_DROP;
223
224 icmph = (struct batadv_icmp_header *)skb->data;
225
226 switch (icmph->msg_type) {
227 case BATADV_ECHO_REQUEST:
228 /* answer echo request (ping) */
229 primary_if = batadv_primary_if_get_selected(bat_priv);
230 if (!primary_if)
231 goto out;
232
233 /* get routing information */
234 orig_node = batadv_orig_hash_find(bat_priv, data: icmph->orig);
235 if (!orig_node)
236 goto out;
237
238 /* create a copy of the skb, if needed, to modify it. */
239 if (skb_cow(skb, ETH_HLEN) < 0)
240 goto out;
241
242 icmph = (struct batadv_icmp_header *)skb->data;
243
244 ether_addr_copy(dst: icmph->dst, src: icmph->orig);
245 ether_addr_copy(dst: icmph->orig, src: primary_if->net_dev->dev_addr);
246 icmph->msg_type = BATADV_ECHO_REPLY;
247 icmph->ttl = BATADV_TTL;
248
249 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
250 if (res == NET_XMIT_SUCCESS)
251 ret = NET_RX_SUCCESS;
252
253 /* skb was consumed */
254 skb = NULL;
255 break;
256 case BATADV_TP:
257 if (!pskb_may_pull(skb, len: sizeof(struct batadv_icmp_tp_packet)))
258 goto out;
259
260 batadv_tp_meter_recv(bat_priv, skb);
261 ret = NET_RX_SUCCESS;
262 /* skb was consumed */
263 skb = NULL;
264 goto out;
265 default:
266 /* drop unknown type */
267 goto out;
268 }
269out:
270 batadv_hardif_put(hard_iface: primary_if);
271 batadv_orig_node_put(orig_node);
272
273 kfree_skb(skb);
274
275 return ret;
276}
277
278static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
279 struct sk_buff *skb)
280{
281 struct batadv_hard_iface *primary_if = NULL;
282 struct batadv_orig_node *orig_node = NULL;
283 struct batadv_icmp_packet *icmp_packet;
284 int res, ret = NET_RX_DROP;
285
286 icmp_packet = (struct batadv_icmp_packet *)skb->data;
287
288 /* send TTL exceeded if packet is an echo request (traceroute) */
289 if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
290 pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
291 icmp_packet->orig, icmp_packet->dst);
292 goto out;
293 }
294
295 primary_if = batadv_primary_if_get_selected(bat_priv);
296 if (!primary_if)
297 goto out;
298
299 /* get routing information */
300 orig_node = batadv_orig_hash_find(bat_priv, data: icmp_packet->orig);
301 if (!orig_node)
302 goto out;
303
304 /* create a copy of the skb, if needed, to modify it. */
305 if (skb_cow(skb, ETH_HLEN) < 0)
306 goto out;
307
308 icmp_packet = (struct batadv_icmp_packet *)skb->data;
309
310 ether_addr_copy(dst: icmp_packet->dst, src: icmp_packet->orig);
311 ether_addr_copy(dst: icmp_packet->orig, src: primary_if->net_dev->dev_addr);
312 icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
313 icmp_packet->ttl = BATADV_TTL;
314
315 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
316 if (res == NET_RX_SUCCESS)
317 ret = NET_XMIT_SUCCESS;
318
319 /* skb was consumed */
320 skb = NULL;
321
322out:
323 batadv_hardif_put(hard_iface: primary_if);
324 batadv_orig_node_put(orig_node);
325
326 kfree_skb(skb);
327
328 return ret;
329}
330
331/**
332 * batadv_recv_icmp_packet() - Process incoming icmp packet
333 * @skb: incoming packet buffer
334 * @recv_if: incoming hard interface
335 *
336 * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
337 */
338int batadv_recv_icmp_packet(struct sk_buff *skb,
339 struct batadv_hard_iface *recv_if)
340{
341 struct batadv_priv *bat_priv = netdev_priv(dev: recv_if->soft_iface);
342 struct batadv_icmp_header *icmph;
343 struct batadv_icmp_packet_rr *icmp_packet_rr;
344 struct ethhdr *ethhdr;
345 struct batadv_orig_node *orig_node = NULL;
346 int hdr_size = sizeof(struct batadv_icmp_header);
347 int res, ret = NET_RX_DROP;
348
349 /* drop packet if it has not necessary minimum size */
350 if (unlikely(!pskb_may_pull(skb, hdr_size)))
351 goto free_skb;
352
353 ethhdr = eth_hdr(skb);
354
355 /* packet with unicast indication but non-unicast recipient */
356 if (!is_valid_ether_addr(addr: ethhdr->h_dest))
357 goto free_skb;
358
359 /* packet with broadcast/multicast sender address */
360 if (is_multicast_ether_addr(addr: ethhdr->h_source))
361 goto free_skb;
362
363 /* not for me */
364 if (!batadv_is_my_mac(bat_priv, addr: ethhdr->h_dest))
365 goto free_skb;
366
367 icmph = (struct batadv_icmp_header *)skb->data;
368
369 /* add record route information if not full */
370 if ((icmph->msg_type == BATADV_ECHO_REPLY ||
371 icmph->msg_type == BATADV_ECHO_REQUEST) &&
372 skb->len >= sizeof(struct batadv_icmp_packet_rr)) {
373 if (skb_linearize(skb) < 0)
374 goto free_skb;
375
376 /* create a copy of the skb, if needed, to modify it. */
377 if (skb_cow(skb, ETH_HLEN) < 0)
378 goto free_skb;
379
380 ethhdr = eth_hdr(skb);
381 icmph = (struct batadv_icmp_header *)skb->data;
382 icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
383 if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
384 goto free_skb;
385
386 ether_addr_copy(dst: icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
387 src: ethhdr->h_dest);
388 icmp_packet_rr->rr_cur++;
389 }
390
391 /* packet for me */
392 if (batadv_is_my_mac(bat_priv, addr: icmph->dst))
393 return batadv_recv_my_icmp_packet(bat_priv, skb);
394
395 /* TTL exceeded */
396 if (icmph->ttl < 2)
397 return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
398
399 /* get routing information */
400 orig_node = batadv_orig_hash_find(bat_priv, data: icmph->dst);
401 if (!orig_node)
402 goto free_skb;
403
404 /* create a copy of the skb, if needed, to modify it. */
405 if (skb_cow(skb, ETH_HLEN) < 0)
406 goto put_orig_node;
407
408 icmph = (struct batadv_icmp_header *)skb->data;
409
410 /* decrement ttl */
411 icmph->ttl--;
412
413 /* route it */
414 res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
415 if (res == NET_XMIT_SUCCESS)
416 ret = NET_RX_SUCCESS;
417
418 /* skb was consumed */
419 skb = NULL;
420
421put_orig_node:
422 batadv_orig_node_put(orig_node);
423free_skb:
424 kfree_skb(skb);
425
426 return ret;
427}
428
429/**
430 * batadv_check_unicast_packet() - Check for malformed unicast packets
431 * @bat_priv: the bat priv with all the soft interface information
432 * @skb: packet to check
433 * @hdr_size: size of header to pull
434 *
435 * Checks for short header and bad addresses in the given packet.
436 *
437 * Return: negative value when check fails and 0 otherwise. The negative value
438 * depends on the reason: -ENODATA for bad header, -EBADR for broadcast
439 * destination or source, and -EREMOTE for non-local (other host) destination.
440 */
441static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
442 struct sk_buff *skb, int hdr_size)
443{
444 struct ethhdr *ethhdr;
445
446 /* drop packet if it has not necessary minimum size */
447 if (unlikely(!pskb_may_pull(skb, hdr_size)))
448 return -ENODATA;
449
450 ethhdr = eth_hdr(skb);
451
452 /* packet with unicast indication but non-unicast recipient */
453 if (!is_valid_ether_addr(addr: ethhdr->h_dest))
454 return -EBADR;
455
456 /* packet with broadcast/multicast sender address */
457 if (is_multicast_ether_addr(addr: ethhdr->h_source))
458 return -EBADR;
459
460 /* not for me */
461 if (!batadv_is_my_mac(bat_priv, addr: ethhdr->h_dest))
462 return -EREMOTE;
463
464 return 0;
465}
466
467/**
468 * batadv_last_bonding_get() - Get last_bonding_candidate of orig_node
469 * @orig_node: originator node whose last bonding candidate should be retrieved
470 *
471 * Return: last bonding candidate of router or NULL if not found
472 *
473 * The object is returned with refcounter increased by 1.
474 */
475static struct batadv_orig_ifinfo *
476batadv_last_bonding_get(struct batadv_orig_node *orig_node)
477{
478 struct batadv_orig_ifinfo *last_bonding_candidate;
479
480 spin_lock_bh(lock: &orig_node->neigh_list_lock);
481 last_bonding_candidate = orig_node->last_bonding_candidate;
482
483 if (last_bonding_candidate)
484 kref_get(kref: &last_bonding_candidate->refcount);
485 spin_unlock_bh(lock: &orig_node->neigh_list_lock);
486
487 return last_bonding_candidate;
488}
489
490/**
491 * batadv_last_bonding_replace() - Replace last_bonding_candidate of orig_node
492 * @orig_node: originator node whose bonding candidates should be replaced
493 * @new_candidate: new bonding candidate or NULL
494 */
495static void
496batadv_last_bonding_replace(struct batadv_orig_node *orig_node,
497 struct batadv_orig_ifinfo *new_candidate)
498{
499 struct batadv_orig_ifinfo *old_candidate;
500
501 spin_lock_bh(lock: &orig_node->neigh_list_lock);
502 old_candidate = orig_node->last_bonding_candidate;
503
504 if (new_candidate)
505 kref_get(kref: &new_candidate->refcount);
506 orig_node->last_bonding_candidate = new_candidate;
507 spin_unlock_bh(lock: &orig_node->neigh_list_lock);
508
509 batadv_orig_ifinfo_put(orig_ifinfo: old_candidate);
510}
511
512/**
513 * batadv_find_router() - find a suitable router for this originator
514 * @bat_priv: the bat priv with all the soft interface information
515 * @orig_node: the destination node
516 * @recv_if: pointer to interface this packet was received on
517 *
518 * Return: the router which should be used for this orig_node on
519 * this interface, or NULL if not available.
520 */
521struct batadv_neigh_node *
522batadv_find_router(struct batadv_priv *bat_priv,
523 struct batadv_orig_node *orig_node,
524 struct batadv_hard_iface *recv_if)
525{
526 struct batadv_algo_ops *bao = bat_priv->algo_ops;
527 struct batadv_neigh_node *first_candidate_router = NULL;
528 struct batadv_neigh_node *next_candidate_router = NULL;
529 struct batadv_neigh_node *router, *cand_router = NULL;
530 struct batadv_neigh_node *last_cand_router = NULL;
531 struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
532 struct batadv_orig_ifinfo *next_candidate = NULL;
533 struct batadv_orig_ifinfo *last_candidate;
534 bool last_candidate_found = false;
535
536 if (!orig_node)
537 return NULL;
538
539 router = batadv_orig_router_get(orig_node, if_outgoing: recv_if);
540
541 if (!router)
542 return router;
543
544 /* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
545 * and if activated.
546 */
547 if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(v: &bat_priv->bonding)))
548 return router;
549
550 /* bonding: loop through the list of possible routers found
551 * for the various outgoing interfaces and find a candidate after
552 * the last chosen bonding candidate (next_candidate). If no such
553 * router is found, use the first candidate found (the previously
554 * chosen bonding candidate might have been the last one in the list).
555 * If this can't be found either, return the previously chosen
556 * router - obviously there are no other candidates.
557 */
558 rcu_read_lock();
559 last_candidate = batadv_last_bonding_get(orig_node);
560 if (last_candidate)
561 last_cand_router = rcu_dereference(last_candidate->router);
562
563 hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
564 /* acquire some structures and references ... */
565 if (!kref_get_unless_zero(kref: &cand->refcount))
566 continue;
567
568 cand_router = rcu_dereference(cand->router);
569 if (!cand_router)
570 goto next;
571
572 if (!kref_get_unless_zero(kref: &cand_router->refcount)) {
573 cand_router = NULL;
574 goto next;
575 }
576
577 /* alternative candidate should be good enough to be
578 * considered
579 */
580 if (!bao->neigh.is_similar_or_better(cand_router,
581 cand->if_outgoing, router,
582 recv_if))
583 goto next;
584
585 /* don't use the same router twice */
586 if (last_cand_router == cand_router)
587 goto next;
588
589 /* mark the first possible candidate */
590 if (!first_candidate) {
591 kref_get(kref: &cand_router->refcount);
592 kref_get(kref: &cand->refcount);
593 first_candidate = cand;
594 first_candidate_router = cand_router;
595 }
596
597 /* check if the loop has already passed the previously selected
598 * candidate ... this function should select the next candidate
599 * AFTER the previously used bonding candidate.
600 */
601 if (!last_candidate || last_candidate_found) {
602 next_candidate = cand;
603 next_candidate_router = cand_router;
604 break;
605 }
606
607 if (last_candidate == cand)
608 last_candidate_found = true;
609next:
610 /* free references */
611 if (cand_router) {
612 batadv_neigh_node_put(neigh_node: cand_router);
613 cand_router = NULL;
614 }
615 batadv_orig_ifinfo_put(orig_ifinfo: cand);
616 }
617 rcu_read_unlock();
618
619 /* After finding candidates, handle the three cases:
620 * 1) there is a next candidate, use that
621 * 2) there is no next candidate, use the first of the list
622 * 3) there is no candidate at all, return the default router
623 */
624 if (next_candidate) {
625 batadv_neigh_node_put(neigh_node: router);
626
627 kref_get(kref: &next_candidate_router->refcount);
628 router = next_candidate_router;
629 batadv_last_bonding_replace(orig_node, new_candidate: next_candidate);
630 } else if (first_candidate) {
631 batadv_neigh_node_put(neigh_node: router);
632
633 kref_get(kref: &first_candidate_router->refcount);
634 router = first_candidate_router;
635 batadv_last_bonding_replace(orig_node, new_candidate: first_candidate);
636 } else {
637 batadv_last_bonding_replace(orig_node, NULL);
638 }
639
640 /* cleanup of candidates */
641 if (first_candidate) {
642 batadv_neigh_node_put(neigh_node: first_candidate_router);
643 batadv_orig_ifinfo_put(orig_ifinfo: first_candidate);
644 }
645
646 if (next_candidate) {
647 batadv_neigh_node_put(neigh_node: next_candidate_router);
648 batadv_orig_ifinfo_put(orig_ifinfo: next_candidate);
649 }
650
651 batadv_orig_ifinfo_put(orig_ifinfo: last_candidate);
652
653 return router;
654}
655
656static int batadv_route_unicast_packet(struct sk_buff *skb,
657 struct batadv_hard_iface *recv_if)
658{
659 struct batadv_priv *bat_priv = netdev_priv(dev: recv_if->soft_iface);
660 struct batadv_orig_node *orig_node = NULL;
661 struct batadv_unicast_packet *unicast_packet;
662 struct ethhdr *ethhdr = eth_hdr(skb);
663 int res, hdr_len, ret = NET_RX_DROP;
664 unsigned int len;
665
666 unicast_packet = (struct batadv_unicast_packet *)skb->data;
667
668 /* TTL exceeded */
669 if (unicast_packet->ttl < 2) {
670 pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
671 ethhdr->h_source, unicast_packet->dest);
672 goto free_skb;
673 }
674
675 /* get routing information */
676 orig_node = batadv_orig_hash_find(bat_priv, data: unicast_packet->dest);
677
678 if (!orig_node)
679 goto free_skb;
680
681 /* create a copy of the skb, if needed, to modify it. */
682 if (skb_cow(skb, ETH_HLEN) < 0)
683 goto put_orig_node;
684
685 /* decrement ttl */
686 unicast_packet = (struct batadv_unicast_packet *)skb->data;
687 unicast_packet->ttl--;
688
689 switch (unicast_packet->packet_type) {
690 case BATADV_UNICAST_4ADDR:
691 hdr_len = sizeof(struct batadv_unicast_4addr_packet);
692 break;
693 case BATADV_UNICAST:
694 hdr_len = sizeof(struct batadv_unicast_packet);
695 break;
696 default:
697 /* other packet types not supported - yet */
698 hdr_len = -1;
699 break;
700 }
701
702 if (hdr_len > 0)
703 batadv_skb_set_priority(skb, offset: hdr_len);
704
705 len = skb->len;
706 res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
707
708 /* translate transmit result into receive result */
709 if (res == NET_XMIT_SUCCESS) {
710 ret = NET_RX_SUCCESS;
711 /* skb was transmitted and consumed */
712 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
713 batadv_add_counter(bat_priv, idx: BATADV_CNT_FORWARD_BYTES,
714 count: len + ETH_HLEN);
715 }
716
717 /* skb was consumed */
718 skb = NULL;
719
720put_orig_node:
721 batadv_orig_node_put(orig_node);
722free_skb:
723 kfree_skb(skb);
724
725 return ret;
726}
727
728/**
729 * batadv_reroute_unicast_packet() - update the unicast header for re-routing
730 * @bat_priv: the bat priv with all the soft interface information
731 * @skb: unicast packet to process
732 * @unicast_packet: the unicast header to be updated
733 * @dst_addr: the payload destination
734 * @vid: VLAN identifier
735 *
736 * Search the translation table for dst_addr and update the unicast header with
737 * the new corresponding information (originator address where the destination
738 * client currently is and its known TTVN)
739 *
740 * Return: true if the packet header has been updated, false otherwise
741 */
742static bool
743batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
744 struct batadv_unicast_packet *unicast_packet,
745 u8 *dst_addr, unsigned short vid)
746{
747 struct batadv_orig_node *orig_node = NULL;
748 struct batadv_hard_iface *primary_if = NULL;
749 bool ret = false;
750 const u8 *orig_addr;
751 u8 orig_ttvn;
752
753 if (batadv_is_my_client(bat_priv, addr: dst_addr, vid)) {
754 primary_if = batadv_primary_if_get_selected(bat_priv);
755 if (!primary_if)
756 goto out;
757 orig_addr = primary_if->net_dev->dev_addr;
758 orig_ttvn = (u8)atomic_read(v: &bat_priv->tt.vn);
759 } else {
760 orig_node = batadv_transtable_search(bat_priv, NULL, addr: dst_addr,
761 vid);
762 if (!orig_node)
763 goto out;
764
765 if (batadv_compare_eth(data1: orig_node->orig, data2: unicast_packet->dest))
766 goto out;
767
768 orig_addr = orig_node->orig;
769 orig_ttvn = (u8)atomic_read(v: &orig_node->last_ttvn);
770 }
771
772 /* update the packet header */
773 skb_postpull_rcsum(skb, start: unicast_packet, len: sizeof(*unicast_packet));
774 ether_addr_copy(dst: unicast_packet->dest, src: orig_addr);
775 unicast_packet->ttvn = orig_ttvn;
776 skb_postpush_rcsum(skb, start: unicast_packet, len: sizeof(*unicast_packet));
777
778 ret = true;
779out:
780 batadv_hardif_put(hard_iface: primary_if);
781 batadv_orig_node_put(orig_node);
782
783 return ret;
784}
785
786static bool batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
787 struct sk_buff *skb, int hdr_len)
788{
789 struct batadv_unicast_packet *unicast_packet;
790 struct batadv_hard_iface *primary_if;
791 struct batadv_orig_node *orig_node;
792 u8 curr_ttvn, old_ttvn;
793 struct ethhdr *ethhdr;
794 unsigned short vid;
795 int is_old_ttvn;
796
797 /* check if there is enough data before accessing it */
798 if (!pskb_may_pull(skb, len: hdr_len + ETH_HLEN))
799 return false;
800
801 /* create a copy of the skb (in case of for re-routing) to modify it. */
802 if (skb_cow(skb, headroom: sizeof(*unicast_packet)) < 0)
803 return false;
804
805 unicast_packet = (struct batadv_unicast_packet *)skb->data;
806 vid = batadv_get_vid(skb, header_len: hdr_len);
807 ethhdr = (struct ethhdr *)(skb->data + hdr_len);
808
809 /* do not reroute multicast frames in a unicast header */
810 if (is_multicast_ether_addr(addr: ethhdr->h_dest))
811 return true;
812
813 /* check if the destination client was served by this node and it is now
814 * roaming. In this case, it means that the node has got a ROAM_ADV
815 * message and that it knows the new destination in the mesh to re-route
816 * the packet to
817 */
818 if (batadv_tt_local_client_is_roaming(bat_priv, addr: ethhdr->h_dest, vid)) {
819 if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
820 dst_addr: ethhdr->h_dest, vid))
821 batadv_dbg_ratelimited(BATADV_DBG_TT,
822 bat_priv,
823 "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
824 unicast_packet->dest,
825 ethhdr->h_dest);
826 /* at this point the mesh destination should have been
827 * substituted with the originator address found in the global
828 * table. If not, let the packet go untouched anyway because
829 * there is nothing the node can do
830 */
831 return true;
832 }
833
834 /* retrieve the TTVN known by this node for the packet destination. This
835 * value is used later to check if the node which sent (or re-routed
836 * last time) the packet had an updated information or not
837 */
838 curr_ttvn = (u8)atomic_read(v: &bat_priv->tt.vn);
839 if (!batadv_is_my_mac(bat_priv, addr: unicast_packet->dest)) {
840 orig_node = batadv_orig_hash_find(bat_priv,
841 data: unicast_packet->dest);
842 /* if it is not possible to find the orig_node representing the
843 * destination, the packet can immediately be dropped as it will
844 * not be possible to deliver it
845 */
846 if (!orig_node)
847 return false;
848
849 curr_ttvn = (u8)atomic_read(v: &orig_node->last_ttvn);
850 batadv_orig_node_put(orig_node);
851 }
852
853 /* check if the TTVN contained in the packet is fresher than what the
854 * node knows
855 */
856 is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
857 if (!is_old_ttvn)
858 return true;
859
860 old_ttvn = unicast_packet->ttvn;
861 /* the packet was forged based on outdated network information. Its
862 * destination can possibly be updated and forwarded towards the new
863 * target host
864 */
865 if (batadv_reroute_unicast_packet(bat_priv, skb, unicast_packet,
866 dst_addr: ethhdr->h_dest, vid)) {
867 batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
868 "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
869 unicast_packet->dest, ethhdr->h_dest,
870 old_ttvn, curr_ttvn);
871 return true;
872 }
873
874 /* the packet has not been re-routed: either the destination is
875 * currently served by this node or there is no destination at all and
876 * it is possible to drop the packet
877 */
878 if (!batadv_is_my_client(bat_priv, addr: ethhdr->h_dest, vid))
879 return false;
880
881 /* update the header in order to let the packet be delivered to this
882 * node's soft interface
883 */
884 primary_if = batadv_primary_if_get_selected(bat_priv);
885 if (!primary_if)
886 return false;
887
888 /* update the packet header */
889 skb_postpull_rcsum(skb, start: unicast_packet, len: sizeof(*unicast_packet));
890 ether_addr_copy(dst: unicast_packet->dest, src: primary_if->net_dev->dev_addr);
891 unicast_packet->ttvn = curr_ttvn;
892 skb_postpush_rcsum(skb, start: unicast_packet, len: sizeof(*unicast_packet));
893
894 batadv_hardif_put(hard_iface: primary_if);
895
896 return true;
897}
898
899/**
900 * batadv_recv_unhandled_unicast_packet() - receive and process packets which
901 * are in the unicast number space but not yet known to the implementation
902 * @skb: unicast tvlv packet to process
903 * @recv_if: pointer to interface this packet was received on
904 *
905 * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
906 * otherwise.
907 */
908int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
909 struct batadv_hard_iface *recv_if)
910{
911 struct batadv_unicast_packet *unicast_packet;
912 struct batadv_priv *bat_priv = netdev_priv(dev: recv_if->soft_iface);
913 int check, hdr_size = sizeof(*unicast_packet);
914
915 check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
916 if (check < 0)
917 goto free_skb;
918
919 /* we don't know about this type, drop it. */
920 unicast_packet = (struct batadv_unicast_packet *)skb->data;
921 if (batadv_is_my_mac(bat_priv, addr: unicast_packet->dest))
922 goto free_skb;
923
924 return batadv_route_unicast_packet(skb, recv_if);
925
926free_skb:
927 kfree_skb(skb);
928 return NET_RX_DROP;
929}
930
931/**
932 * batadv_recv_unicast_packet() - Process incoming unicast packet
933 * @skb: incoming packet buffer
934 * @recv_if: incoming hard interface
935 *
936 * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
937 */
938int batadv_recv_unicast_packet(struct sk_buff *skb,
939 struct batadv_hard_iface *recv_if)
940{
941 struct batadv_priv *bat_priv = netdev_priv(dev: recv_if->soft_iface);
942 struct batadv_unicast_packet *unicast_packet;
943 struct batadv_unicast_4addr_packet *unicast_4addr_packet;
944 u8 *orig_addr, *orig_addr_gw;
945 struct batadv_orig_node *orig_node = NULL, *orig_node_gw = NULL;
946 int check, hdr_size = sizeof(*unicast_packet);
947 enum batadv_subtype subtype;
948 int ret = NET_RX_DROP;
949 bool is4addr, is_gw;
950
951 unicast_packet = (struct batadv_unicast_packet *)skb->data;
952 is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
953 /* the caller function should have already pulled 2 bytes */
954 if (is4addr)
955 hdr_size = sizeof(*unicast_4addr_packet);
956
957 /* function returns -EREMOTE for promiscuous packets */
958 check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
959
960 /* Even though the packet is not for us, we might save it to use for
961 * decoding a later received coded packet
962 */
963 if (check == -EREMOTE)
964 batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
965
966 if (check < 0)
967 goto free_skb;
968 if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_len: hdr_size))
969 goto free_skb;
970
971 unicast_packet = (struct batadv_unicast_packet *)skb->data;
972
973 /* packet for me */
974 if (batadv_is_my_mac(bat_priv, addr: unicast_packet->dest)) {
975 /* If this is a unicast packet from another backgone gw,
976 * drop it.
977 */
978 orig_addr_gw = eth_hdr(skb)->h_source;
979 orig_node_gw = batadv_orig_hash_find(bat_priv, data: orig_addr_gw);
980 if (orig_node_gw) {
981 is_gw = batadv_bla_is_backbone_gw(skb, orig_node: orig_node_gw,
982 hdr_size);
983 batadv_orig_node_put(orig_node: orig_node_gw);
984 if (is_gw) {
985 batadv_dbg(BATADV_DBG_BLA, bat_priv,
986 "%s(): Dropped unicast pkt received from another backbone gw %pM.\n",
987 __func__, orig_addr_gw);
988 goto free_skb;
989 }
990 }
991
992 if (is4addr) {
993 unicast_4addr_packet =
994 (struct batadv_unicast_4addr_packet *)skb->data;
995 subtype = unicast_4addr_packet->subtype;
996 batadv_dat_inc_counter(bat_priv, subtype);
997
998 /* Only payload data should be considered for speedy
999 * join. For example, DAT also uses unicast 4addr
1000 * types, but those packets should not be considered
1001 * for speedy join, since the clients do not actually
1002 * reside at the sending originator.
1003 */
1004 if (subtype == BATADV_P_DATA) {
1005 orig_addr = unicast_4addr_packet->src;
1006 orig_node = batadv_orig_hash_find(bat_priv,
1007 data: orig_addr);
1008 }
1009 }
1010
1011 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
1012 hdr_size))
1013 goto rx_success;
1014 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
1015 hdr_size))
1016 goto rx_success;
1017
1018 batadv_dat_snoop_incoming_dhcp_ack(bat_priv, skb, hdr_size);
1019
1020 batadv_interface_rx(soft_iface: recv_if->soft_iface, skb, hdr_size,
1021 orig_node);
1022
1023rx_success:
1024 batadv_orig_node_put(orig_node);
1025
1026 return NET_RX_SUCCESS;
1027 }
1028
1029 ret = batadv_route_unicast_packet(skb, recv_if);
1030 /* skb was consumed */
1031 skb = NULL;
1032
1033free_skb:
1034 kfree_skb(skb);
1035
1036 return ret;
1037}
1038
1039/**
1040 * batadv_recv_unicast_tvlv() - receive and process unicast tvlv packets
1041 * @skb: unicast tvlv packet to process
1042 * @recv_if: pointer to interface this packet was received on
1043 *
1044 * Return: NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
1045 * otherwise.
1046 */
1047int batadv_recv_unicast_tvlv(struct sk_buff *skb,
1048 struct batadv_hard_iface *recv_if)
1049{
1050 struct batadv_priv *bat_priv = netdev_priv(dev: recv_if->soft_iface);
1051 struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
1052 unsigned char *tvlv_buff;
1053 u16 tvlv_buff_len;
1054 int hdr_size = sizeof(*unicast_tvlv_packet);
1055 int ret = NET_RX_DROP;
1056
1057 if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
1058 goto free_skb;
1059
1060 /* the header is likely to be modified while forwarding */
1061 if (skb_cow(skb, headroom: hdr_size) < 0)
1062 goto free_skb;
1063
1064 /* packet needs to be linearized to access the tvlv content */
1065 if (skb_linearize(skb) < 0)
1066 goto free_skb;
1067
1068 unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
1069
1070 tvlv_buff = (unsigned char *)(skb->data + hdr_size);
1071 tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
1072
1073 if (tvlv_buff_len > skb->len - hdr_size)
1074 goto free_skb;
1075
1076 ret = batadv_tvlv_containers_process(bat_priv, packet_type: BATADV_UNICAST_TVLV,
1077 NULL, skb, tvlv_buff,
1078 tvlv_buff_len);
1079
1080 if (ret != NET_RX_SUCCESS) {
1081 ret = batadv_route_unicast_packet(skb, recv_if);
1082 /* skb was consumed */
1083 skb = NULL;
1084 }
1085
1086free_skb:
1087 kfree_skb(skb);
1088
1089 return ret;
1090}
1091
1092/**
1093 * batadv_recv_frag_packet() - process received fragment
1094 * @skb: the received fragment
1095 * @recv_if: interface that the skb is received on
1096 *
1097 * This function does one of the three following things: 1) Forward fragment, if
1098 * the assembled packet will exceed our MTU; 2) Buffer fragment, if we still
1099 * lack further fragments; 3) Merge fragments, if we have all needed parts.
1100 *
1101 * Return: NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
1102 */
1103int batadv_recv_frag_packet(struct sk_buff *skb,
1104 struct batadv_hard_iface *recv_if)
1105{
1106 struct batadv_priv *bat_priv = netdev_priv(dev: recv_if->soft_iface);
1107 struct batadv_orig_node *orig_node_src = NULL;
1108 struct batadv_frag_packet *frag_packet;
1109 int ret = NET_RX_DROP;
1110
1111 if (batadv_check_unicast_packet(bat_priv, skb,
1112 hdr_size: sizeof(*frag_packet)) < 0)
1113 goto free_skb;
1114
1115 frag_packet = (struct batadv_frag_packet *)skb->data;
1116 orig_node_src = batadv_orig_hash_find(bat_priv, data: frag_packet->orig);
1117 if (!orig_node_src)
1118 goto free_skb;
1119
1120 skb->priority = frag_packet->priority + 256;
1121
1122 /* Route the fragment if it is not for us and too big to be merged. */
1123 if (!batadv_is_my_mac(bat_priv, addr: frag_packet->dest) &&
1124 batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
1125 /* skb was consumed */
1126 skb = NULL;
1127 ret = NET_RX_SUCCESS;
1128 goto put_orig_node;
1129 }
1130
1131 batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
1132 batadv_add_counter(bat_priv, idx: BATADV_CNT_FRAG_RX_BYTES, count: skb->len);
1133
1134 /* Add fragment to buffer and merge if possible. */
1135 if (!batadv_frag_skb_buffer(skb: &skb, orig_node: orig_node_src))
1136 goto put_orig_node;
1137
1138 /* Deliver merged packet to the appropriate handler, if it was
1139 * merged
1140 */
1141 if (skb) {
1142 batadv_batman_skb_recv(skb, dev: recv_if->net_dev,
1143 ptype: &recv_if->batman_adv_ptype, NULL);
1144 /* skb was consumed */
1145 skb = NULL;
1146 }
1147
1148 ret = NET_RX_SUCCESS;
1149
1150put_orig_node:
1151 batadv_orig_node_put(orig_node: orig_node_src);
1152free_skb:
1153 kfree_skb(skb);
1154
1155 return ret;
1156}
1157
1158/**
1159 * batadv_recv_bcast_packet() - Process incoming broadcast packet
1160 * @skb: incoming packet buffer
1161 * @recv_if: incoming hard interface
1162 *
1163 * Return: NET_RX_SUCCESS on success or NET_RX_DROP in case of failure
1164 */
1165int batadv_recv_bcast_packet(struct sk_buff *skb,
1166 struct batadv_hard_iface *recv_if)
1167{
1168 struct batadv_priv *bat_priv = netdev_priv(dev: recv_if->soft_iface);
1169 struct batadv_orig_node *orig_node = NULL;
1170 struct batadv_bcast_packet *bcast_packet;
1171 struct ethhdr *ethhdr;
1172 int hdr_size = sizeof(*bcast_packet);
1173 s32 seq_diff;
1174 u32 seqno;
1175 int ret;
1176
1177 /* drop packet if it has not necessary minimum size */
1178 if (unlikely(!pskb_may_pull(skb, hdr_size)))
1179 goto free_skb;
1180
1181 ethhdr = eth_hdr(skb);
1182
1183 /* packet with broadcast indication but unicast recipient */
1184 if (!is_broadcast_ether_addr(addr: ethhdr->h_dest))
1185 goto free_skb;
1186
1187 /* packet with broadcast/multicast sender address */
1188 if (is_multicast_ether_addr(addr: ethhdr->h_source))
1189 goto free_skb;
1190
1191 /* ignore broadcasts sent by myself */
1192 if (batadv_is_my_mac(bat_priv, addr: ethhdr->h_source))
1193 goto free_skb;
1194
1195 bcast_packet = (struct batadv_bcast_packet *)skb->data;
1196
1197 /* ignore broadcasts originated by myself */
1198 if (batadv_is_my_mac(bat_priv, addr: bcast_packet->orig))
1199 goto free_skb;
1200
1201 if (bcast_packet->ttl-- < 2)
1202 goto free_skb;
1203
1204 orig_node = batadv_orig_hash_find(bat_priv, data: bcast_packet->orig);
1205
1206 if (!orig_node)
1207 goto free_skb;
1208
1209 spin_lock_bh(lock: &orig_node->bcast_seqno_lock);
1210
1211 seqno = ntohl(bcast_packet->seqno);
1212 /* check whether the packet is a duplicate */
1213 if (batadv_test_bit(seq_bits: orig_node->bcast_bits, last_seqno: orig_node->last_bcast_seqno,
1214 curr_seqno: seqno))
1215 goto spin_unlock;
1216
1217 seq_diff = seqno - orig_node->last_bcast_seqno;
1218
1219 /* check whether the packet is old and the host just restarted. */
1220 if (batadv_window_protected(bat_priv, seq_num_diff: seq_diff,
1221 BATADV_BCAST_MAX_AGE,
1222 last_reset: &orig_node->bcast_seqno_reset, NULL))
1223 goto spin_unlock;
1224
1225 /* mark broadcast in flood history, update window position
1226 * if required.
1227 */
1228 if (batadv_bit_get_packet(priv: bat_priv, seq_bits: orig_node->bcast_bits, seq_num_diff: seq_diff, set_mark: 1))
1229 orig_node->last_bcast_seqno = seqno;
1230
1231 spin_unlock_bh(lock: &orig_node->bcast_seqno_lock);
1232
1233 /* check whether this has been sent by another originator before */
1234 if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1235 goto free_skb;
1236
1237 batadv_skb_set_priority(skb, offset: sizeof(struct batadv_bcast_packet));
1238
1239 /* rebroadcast packet */
1240 ret = batadv_forw_bcast_packet(bat_priv, skb, delay: 0, own_packet: false);
1241 if (ret == NETDEV_TX_BUSY)
1242 goto free_skb;
1243
1244 /* don't hand the broadcast up if it is from an originator
1245 * from the same backbone.
1246 */
1247 if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1248 goto free_skb;
1249
1250 if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1251 goto rx_success;
1252 if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1253 goto rx_success;
1254
1255 batadv_dat_snoop_incoming_dhcp_ack(bat_priv, skb, hdr_size);
1256
1257 /* broadcast for me */
1258 batadv_interface_rx(soft_iface: recv_if->soft_iface, skb, hdr_size, orig_node);
1259
1260rx_success:
1261 ret = NET_RX_SUCCESS;
1262 goto out;
1263
1264spin_unlock:
1265 spin_unlock_bh(lock: &orig_node->bcast_seqno_lock);
1266free_skb:
1267 kfree_skb(skb);
1268 ret = NET_RX_DROP;
1269out:
1270 batadv_orig_node_put(orig_node);
1271 return ret;
1272}
1273

source code of linux/net/batman-adv/routing.c