1/* Copyright (C) 2007-2014 B.A.T.M.A.N. contributors:
2 *
3 * Marek Lindner, Simon Wunderlich
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of version 2 of the GNU General Public
7 * License as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
16 */
17
18#include "main.h"
19#include "routing.h"
20#include "send.h"
21#include "soft-interface.h"
22#include "hard-interface.h"
23#include "icmp_socket.h"
24#include "translation-table.h"
25#include "originator.h"
26#include "bridge_loop_avoidance.h"
27#include "distributed-arp-table.h"
28#include "network-coding.h"
29#include "fragmentation.h"
30
31#include <linux/if_vlan.h>
32
33static int batadv_route_unicast_packet(struct sk_buff *skb,
34				       struct batadv_hard_iface *recv_if);
35
36/**
37 * _batadv_update_route - set the router for this originator
38 * @bat_priv: the bat priv with all the soft interface information
39 * @orig_node: orig node which is to be configured
40 * @recv_if: the receive interface for which this route is set
41 * @neigh_node: neighbor which should be the next router
42 *
43 * This function does not perform any error checks
44 */
45static void _batadv_update_route(struct batadv_priv *bat_priv,
46				 struct batadv_orig_node *orig_node,
47				 struct batadv_hard_iface *recv_if,
48				 struct batadv_neigh_node *neigh_node)
49{
50	struct batadv_orig_ifinfo *orig_ifinfo;
51	struct batadv_neigh_node *curr_router;
52
53	orig_ifinfo = batadv_orig_ifinfo_get(orig_node, recv_if);
54	if (!orig_ifinfo)
55		return;
56
57	rcu_read_lock();
58	curr_router = rcu_dereference(orig_ifinfo->router);
59	if (curr_router && !atomic_inc_not_zero(&curr_router->refcount))
60		curr_router = NULL;
61	rcu_read_unlock();
62
63	/* route deleted */
64	if ((curr_router) && (!neigh_node)) {
65		batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
66			   "Deleting route towards: %pM\n", orig_node->orig);
67		batadv_tt_global_del_orig(bat_priv, orig_node, -1,
68					  "Deleted route towards originator");
69
70	/* route added */
71	} else if ((!curr_router) && (neigh_node)) {
72		batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
73			   "Adding route towards: %pM (via %pM)\n",
74			   orig_node->orig, neigh_node->addr);
75	/* route changed */
76	} else if (neigh_node && curr_router) {
77		batadv_dbg(BATADV_DBG_ROUTES, bat_priv,
78			   "Changing route towards: %pM (now via %pM - was via %pM)\n",
79			   orig_node->orig, neigh_node->addr,
80			   curr_router->addr);
81	}
82
83	if (curr_router)
84		batadv_neigh_node_free_ref(curr_router);
85
86	/* increase refcount of new best neighbor */
87	if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount))
88		neigh_node = NULL;
89
90	spin_lock_bh(&orig_node->neigh_list_lock);
91	rcu_assign_pointer(orig_ifinfo->router, neigh_node);
92	spin_unlock_bh(&orig_node->neigh_list_lock);
93	batadv_orig_ifinfo_free_ref(orig_ifinfo);
94
95	/* decrease refcount of previous best neighbor */
96	if (curr_router)
97		batadv_neigh_node_free_ref(curr_router);
98}
99
100/**
101 * batadv_update_route - set the router for this originator
102 * @bat_priv: the bat priv with all the soft interface information
103 * @orig_node: orig node which is to be configured
104 * @recv_if: the receive interface for which this route is set
105 * @neigh_node: neighbor which should be the next router
106 */
107void batadv_update_route(struct batadv_priv *bat_priv,
108			 struct batadv_orig_node *orig_node,
109			 struct batadv_hard_iface *recv_if,
110			 struct batadv_neigh_node *neigh_node)
111{
112	struct batadv_neigh_node *router = NULL;
113
114	if (!orig_node)
115		goto out;
116
117	router = batadv_orig_router_get(orig_node, recv_if);
118
119	if (router != neigh_node)
120		_batadv_update_route(bat_priv, orig_node, recv_if, neigh_node);
121
122out:
123	if (router)
124		batadv_neigh_node_free_ref(router);
125}
126
127/* checks whether the host restarted and is in the protection time.
128 * returns:
129 *  0 if the packet is to be accepted
130 *  1 if the packet is to be ignored.
131 */
132int batadv_window_protected(struct batadv_priv *bat_priv, int32_t seq_num_diff,
133			    unsigned long *last_reset)
134{
135	if (seq_num_diff <= -BATADV_TQ_LOCAL_WINDOW_SIZE ||
136	    seq_num_diff >= BATADV_EXPECTED_SEQNO_RANGE) {
137		if (!batadv_has_timed_out(*last_reset,
138					  BATADV_RESET_PROTECTION_MS))
139			return 1;
140
141		*last_reset = jiffies;
142		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
143			   "old packet received, start protection\n");
144	}
145
146	return 0;
147}
148
149bool batadv_check_management_packet(struct sk_buff *skb,
150				    struct batadv_hard_iface *hard_iface,
151				    int header_len)
152{
153	struct ethhdr *ethhdr;
154
155	/* drop packet if it has not necessary minimum size */
156	if (unlikely(!pskb_may_pull(skb, header_len)))
157		return false;
158
159	ethhdr = eth_hdr(skb);
160
161	/* packet with broadcast indication but unicast recipient */
162	if (!is_broadcast_ether_addr(ethhdr->h_dest))
163		return false;
164
165	/* packet with broadcast sender address */
166	if (is_broadcast_ether_addr(ethhdr->h_source))
167		return false;
168
169	/* create a copy of the skb, if needed, to modify it. */
170	if (skb_cow(skb, 0) < 0)
171		return false;
172
173	/* keep skb linear */
174	if (skb_linearize(skb) < 0)
175		return false;
176
177	return true;
178}
179
180/**
181 * batadv_recv_my_icmp_packet - receive an icmp packet locally
182 * @bat_priv: the bat priv with all the soft interface information
183 * @skb: icmp packet to process
184 *
185 * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
186 * otherwise.
187 */
188static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
189				      struct sk_buff *skb)
190{
191	struct batadv_hard_iface *primary_if = NULL;
192	struct batadv_orig_node *orig_node = NULL;
193	struct batadv_icmp_header *icmph;
194	int res, ret = NET_RX_DROP;
195
196	icmph = (struct batadv_icmp_header *)skb->data;
197
198	switch (icmph->msg_type) {
199	case BATADV_ECHO_REPLY:
200	case BATADV_DESTINATION_UNREACHABLE:
201	case BATADV_TTL_EXCEEDED:
202		/* receive the packet */
203		if (skb_linearize(skb) < 0)
204			break;
205
206		batadv_socket_receive_packet(icmph, skb->len);
207		break;
208	case BATADV_ECHO_REQUEST:
209		/* answer echo request (ping) */
210		primary_if = batadv_primary_if_get_selected(bat_priv);
211		if (!primary_if)
212			goto out;
213
214		/* get routing information */
215		orig_node = batadv_orig_hash_find(bat_priv, icmph->orig);
216		if (!orig_node)
217			goto out;
218
219		/* create a copy of the skb, if needed, to modify it. */
220		if (skb_cow(skb, ETH_HLEN) < 0)
221			goto out;
222
223		icmph = (struct batadv_icmp_header *)skb->data;
224
225		ether_addr_copy(icmph->dst, icmph->orig);
226		ether_addr_copy(icmph->orig, primary_if->net_dev->dev_addr);
227		icmph->msg_type = BATADV_ECHO_REPLY;
228		icmph->ttl = BATADV_TTL;
229
230		res = batadv_send_skb_to_orig(skb, orig_node, NULL);
231		if (res != NET_XMIT_DROP)
232			ret = NET_RX_SUCCESS;
233
234		break;
235	default:
236		/* drop unknown type */
237		goto out;
238	}
239out:
240	if (primary_if)
241		batadv_hardif_free_ref(primary_if);
242	if (orig_node)
243		batadv_orig_node_free_ref(orig_node);
244	return ret;
245}
246
247static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
248					 struct sk_buff *skb)
249{
250	struct batadv_hard_iface *primary_if = NULL;
251	struct batadv_orig_node *orig_node = NULL;
252	struct batadv_icmp_packet *icmp_packet;
253	int ret = NET_RX_DROP;
254
255	icmp_packet = (struct batadv_icmp_packet *)skb->data;
256
257	/* send TTL exceeded if packet is an echo request (traceroute) */
258	if (icmp_packet->msg_type != BATADV_ECHO_REQUEST) {
259		pr_debug("Warning - can't forward icmp packet from %pM to %pM: ttl exceeded\n",
260			 icmp_packet->orig, icmp_packet->dst);
261		goto out;
262	}
263
264	primary_if = batadv_primary_if_get_selected(bat_priv);
265	if (!primary_if)
266		goto out;
267
268	/* get routing information */
269	orig_node = batadv_orig_hash_find(bat_priv, icmp_packet->orig);
270	if (!orig_node)
271		goto out;
272
273	/* create a copy of the skb, if needed, to modify it. */
274	if (skb_cow(skb, ETH_HLEN) < 0)
275		goto out;
276
277	icmp_packet = (struct batadv_icmp_packet *)skb->data;
278
279	ether_addr_copy(icmp_packet->dst, icmp_packet->orig);
280	ether_addr_copy(icmp_packet->orig, primary_if->net_dev->dev_addr);
281	icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
282	icmp_packet->ttl = BATADV_TTL;
283
284	if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
285		ret = NET_RX_SUCCESS;
286
287out:
288	if (primary_if)
289		batadv_hardif_free_ref(primary_if);
290	if (orig_node)
291		batadv_orig_node_free_ref(orig_node);
292	return ret;
293}
294
295int batadv_recv_icmp_packet(struct sk_buff *skb,
296			    struct batadv_hard_iface *recv_if)
297{
298	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
299	struct batadv_icmp_header *icmph;
300	struct batadv_icmp_packet_rr *icmp_packet_rr;
301	struct ethhdr *ethhdr;
302	struct batadv_orig_node *orig_node = NULL;
303	int hdr_size = sizeof(struct batadv_icmp_header);
304	int ret = NET_RX_DROP;
305
306	/* drop packet if it has not necessary minimum size */
307	if (unlikely(!pskb_may_pull(skb, hdr_size)))
308		goto out;
309
310	ethhdr = eth_hdr(skb);
311
312	/* packet with unicast indication but broadcast recipient */
313	if (is_broadcast_ether_addr(ethhdr->h_dest))
314		goto out;
315
316	/* packet with broadcast sender address */
317	if (is_broadcast_ether_addr(ethhdr->h_source))
318		goto out;
319
320	/* not for me */
321	if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
322		goto out;
323
324	icmph = (struct batadv_icmp_header *)skb->data;
325
326	/* add record route information if not full */
327	if ((icmph->msg_type == BATADV_ECHO_REPLY ||
328	     icmph->msg_type == BATADV_ECHO_REQUEST) &&
329	    (skb->len >= sizeof(struct batadv_icmp_packet_rr))) {
330		if (skb_linearize(skb) < 0)
331			goto out;
332
333		/* create a copy of the skb, if needed, to modify it. */
334		if (skb_cow(skb, ETH_HLEN) < 0)
335			goto out;
336
337		icmph = (struct batadv_icmp_header *)skb->data;
338		icmp_packet_rr = (struct batadv_icmp_packet_rr *)icmph;
339		if (icmp_packet_rr->rr_cur >= BATADV_RR_LEN)
340			goto out;
341
342		ether_addr_copy(icmp_packet_rr->rr[icmp_packet_rr->rr_cur],
343				ethhdr->h_dest);
344		icmp_packet_rr->rr_cur++;
345	}
346
347	/* packet for me */
348	if (batadv_is_my_mac(bat_priv, icmph->dst))
349		return batadv_recv_my_icmp_packet(bat_priv, skb);
350
351	/* TTL exceeded */
352	if (icmph->ttl < 2)
353		return batadv_recv_icmp_ttl_exceeded(bat_priv, skb);
354
355	/* get routing information */
356	orig_node = batadv_orig_hash_find(bat_priv, icmph->dst);
357	if (!orig_node)
358		goto out;
359
360	/* create a copy of the skb, if needed, to modify it. */
361	if (skb_cow(skb, ETH_HLEN) < 0)
362		goto out;
363
364	icmph = (struct batadv_icmp_header *)skb->data;
365
366	/* decrement ttl */
367	icmph->ttl--;
368
369	/* route it */
370	if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
371		ret = NET_RX_SUCCESS;
372
373out:
374	if (orig_node)
375		batadv_orig_node_free_ref(orig_node);
376	return ret;
377}
378
379/**
380 * batadv_check_unicast_packet - Check for malformed unicast packets
381 * @bat_priv: the bat priv with all the soft interface information
382 * @skb: packet to check
383 * @hdr_size: size of header to pull
384 *
385 * Check for short header and bad addresses in given packet. Returns negative
386 * value when check fails and 0 otherwise. The negative value depends on the
387 * reason: -ENODATA for bad header, -EBADR for broadcast destination or source,
388 * and -EREMOTE for non-local (other host) destination.
389 */
390static int batadv_check_unicast_packet(struct batadv_priv *bat_priv,
391				       struct sk_buff *skb, int hdr_size)
392{
393	struct ethhdr *ethhdr;
394
395	/* drop packet if it has not necessary minimum size */
396	if (unlikely(!pskb_may_pull(skb, hdr_size)))
397		return -ENODATA;
398
399	ethhdr = eth_hdr(skb);
400
401	/* packet with unicast indication but broadcast recipient */
402	if (is_broadcast_ether_addr(ethhdr->h_dest))
403		return -EBADR;
404
405	/* packet with broadcast sender address */
406	if (is_broadcast_ether_addr(ethhdr->h_source))
407		return -EBADR;
408
409	/* not for me */
410	if (!batadv_is_my_mac(bat_priv, ethhdr->h_dest))
411		return -EREMOTE;
412
413	return 0;
414}
415
416/**
417 * batadv_find_router - find a suitable router for this originator
418 * @bat_priv: the bat priv with all the soft interface information
419 * @orig_node: the destination node
420 * @recv_if: pointer to interface this packet was received on
421 *
422 * Returns the router which should be used for this orig_node on
423 * this interface, or NULL if not available.
424 */
425struct batadv_neigh_node *
426batadv_find_router(struct batadv_priv *bat_priv,
427		   struct batadv_orig_node *orig_node,
428		   struct batadv_hard_iface *recv_if)
429{
430	struct batadv_algo_ops *bao = bat_priv->bat_algo_ops;
431	struct batadv_neigh_node *first_candidate_router = NULL;
432	struct batadv_neigh_node *next_candidate_router = NULL;
433	struct batadv_neigh_node *router, *cand_router = NULL;
434	struct batadv_neigh_node *last_cand_router = NULL;
435	struct batadv_orig_ifinfo *cand, *first_candidate = NULL;
436	struct batadv_orig_ifinfo *next_candidate = NULL;
437	struct batadv_orig_ifinfo *last_candidate;
438	bool last_candidate_found = false;
439
440	if (!orig_node)
441		return NULL;
442
443	router = batadv_orig_router_get(orig_node, recv_if);
444
445	if (!router)
446		return router;
447
448	/* only consider bonding for recv_if == BATADV_IF_DEFAULT (first hop)
449	 * and if activated.
450	 */
451	if (!(recv_if == BATADV_IF_DEFAULT && atomic_read(&bat_priv->bonding)))
452		return router;
453
454	/* bonding: loop through the list of possible routers found
455	 * for the various outgoing interfaces and find a candidate after
456	 * the last chosen bonding candidate (next_candidate). If no such
457	 * router is found, use the first candidate found (the previously
458	 * chosen bonding candidate might have been the last one in the list).
459	 * If this can't be found either, return the previously chosen
460	 * router - obviously there are no other candidates.
461	 */
462	rcu_read_lock();
463	last_candidate = orig_node->last_bonding_candidate;
464	if (last_candidate)
465		last_cand_router = rcu_dereference(last_candidate->router);
466
467	hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
468		/* acquire some structures and references ... */
469		if (!atomic_inc_not_zero(&cand->refcount))
470			continue;
471
472		cand_router = rcu_dereference(cand->router);
473		if (!cand_router)
474			goto next;
475
476		if (!atomic_inc_not_zero(&cand_router->refcount)) {
477			cand_router = NULL;
478			goto next;
479		}
480
481		/* alternative candidate should be good enough to be
482		 * considered
483		 */
484		if (!bao->bat_neigh_is_equiv_or_better(cand_router,
485						       cand->if_outgoing,
486						       router, recv_if))
487			goto next;
488
489		/* don't use the same router twice */
490		if (last_cand_router == cand_router)
491			goto next;
492
493		/* mark the first possible candidate */
494		if (!first_candidate) {
495			atomic_inc(&cand_router->refcount);
496			atomic_inc(&cand->refcount);
497			first_candidate = cand;
498			first_candidate_router = cand_router;
499		}
500
501		/* check if the loop has already passed the previously selected
502		 * candidate ... this function should select the next candidate
503		 * AFTER the previously used bonding candidate.
504		 */
505		if (!last_candidate || last_candidate_found) {
506			next_candidate = cand;
507			next_candidate_router = cand_router;
508			break;
509		}
510
511		if (last_candidate == cand)
512			last_candidate_found = true;
513next:
514		/* free references */
515		if (cand_router) {
516			batadv_neigh_node_free_ref(cand_router);
517			cand_router = NULL;
518		}
519		batadv_orig_ifinfo_free_ref(cand);
520	}
521	rcu_read_unlock();
522
523	/* last_bonding_candidate is reset below, remove the old reference. */
524	if (orig_node->last_bonding_candidate)
525		batadv_orig_ifinfo_free_ref(orig_node->last_bonding_candidate);
526
527	/* After finding candidates, handle the three cases:
528	 * 1) there is a next candidate, use that
529	 * 2) there is no next candidate, use the first of the list
530	 * 3) there is no candidate at all, return the default router
531	 */
532	if (next_candidate) {
533		batadv_neigh_node_free_ref(router);
534
535		/* remove references to first candidate, we don't need it. */
536		if (first_candidate) {
537			batadv_neigh_node_free_ref(first_candidate_router);
538			batadv_orig_ifinfo_free_ref(first_candidate);
539		}
540		router = next_candidate_router;
541		orig_node->last_bonding_candidate = next_candidate;
542	} else if (first_candidate) {
543		batadv_neigh_node_free_ref(router);
544
545		/* refcounting has already been done in the loop above. */
546		router = first_candidate_router;
547		orig_node->last_bonding_candidate = first_candidate;
548	} else {
549		orig_node->last_bonding_candidate = NULL;
550	}
551
552	return router;
553}
554
555static int batadv_route_unicast_packet(struct sk_buff *skb,
556				       struct batadv_hard_iface *recv_if)
557{
558	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
559	struct batadv_orig_node *orig_node = NULL;
560	struct batadv_unicast_packet *unicast_packet;
561	struct ethhdr *ethhdr = eth_hdr(skb);
562	int res, hdr_len, ret = NET_RX_DROP;
563
564	unicast_packet = (struct batadv_unicast_packet *)skb->data;
565
566	/* TTL exceeded */
567	if (unicast_packet->ttl < 2) {
568		pr_debug("Warning - can't forward unicast packet from %pM to %pM: ttl exceeded\n",
569			 ethhdr->h_source, unicast_packet->dest);
570		goto out;
571	}
572
573	/* get routing information */
574	orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest);
575
576	if (!orig_node)
577		goto out;
578
579	/* create a copy of the skb, if needed, to modify it. */
580	if (skb_cow(skb, ETH_HLEN) < 0)
581		goto out;
582
583	/* decrement ttl */
584	unicast_packet = (struct batadv_unicast_packet *)skb->data;
585	unicast_packet->ttl--;
586
587	switch (unicast_packet->packet_type) {
588	case BATADV_UNICAST_4ADDR:
589		hdr_len = sizeof(struct batadv_unicast_4addr_packet);
590		break;
591	case BATADV_UNICAST:
592		hdr_len = sizeof(struct batadv_unicast_packet);
593		break;
594	default:
595		/* other packet types not supported - yet */
596		hdr_len = -1;
597		break;
598	}
599
600	if (hdr_len > 0)
601		batadv_skb_set_priority(skb, hdr_len);
602
603	res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
604
605	/* translate transmit result into receive result */
606	if (res == NET_XMIT_SUCCESS) {
607		/* skb was transmitted and consumed */
608		batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
609		batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
610				   skb->len + ETH_HLEN);
611
612		ret = NET_RX_SUCCESS;
613	} else if (res == NET_XMIT_POLICED) {
614		/* skb was buffered and consumed */
615		ret = NET_RX_SUCCESS;
616	}
617
618out:
619	if (orig_node)
620		batadv_orig_node_free_ref(orig_node);
621	return ret;
622}
623
624/**
625 * batadv_reroute_unicast_packet - update the unicast header for re-routing
626 * @bat_priv: the bat priv with all the soft interface information
627 * @unicast_packet: the unicast header to be updated
628 * @dst_addr: the payload destination
629 * @vid: VLAN identifier
630 *
631 * Search the translation table for dst_addr and update the unicast header with
632 * the new corresponding information (originator address where the destination
633 * client currently is and its known TTVN)
634 *
635 * Returns true if the packet header has been updated, false otherwise
636 */
637static bool
638batadv_reroute_unicast_packet(struct batadv_priv *bat_priv,
639			      struct batadv_unicast_packet *unicast_packet,
640			      uint8_t *dst_addr, unsigned short vid)
641{
642	struct batadv_orig_node *orig_node = NULL;
643	struct batadv_hard_iface *primary_if = NULL;
644	bool ret = false;
645	uint8_t *orig_addr, orig_ttvn;
646
647	if (batadv_is_my_client(bat_priv, dst_addr, vid)) {
648		primary_if = batadv_primary_if_get_selected(bat_priv);
649		if (!primary_if)
650			goto out;
651		orig_addr = primary_if->net_dev->dev_addr;
652		orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
653	} else {
654		orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr,
655						     vid);
656		if (!orig_node)
657			goto out;
658
659		if (batadv_compare_eth(orig_node->orig, unicast_packet->dest))
660			goto out;
661
662		orig_addr = orig_node->orig;
663		orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
664	}
665
666	/* update the packet header */
667	ether_addr_copy(unicast_packet->dest, orig_addr);
668	unicast_packet->ttvn = orig_ttvn;
669
670	ret = true;
671out:
672	if (primary_if)
673		batadv_hardif_free_ref(primary_if);
674	if (orig_node)
675		batadv_orig_node_free_ref(orig_node);
676
677	return ret;
678}
679
680static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv,
681				     struct sk_buff *skb, int hdr_len) {
682	struct batadv_unicast_packet *unicast_packet;
683	struct batadv_hard_iface *primary_if;
684	struct batadv_orig_node *orig_node;
685	uint8_t curr_ttvn, old_ttvn;
686	struct ethhdr *ethhdr;
687	unsigned short vid;
688	int is_old_ttvn;
689
690	/* check if there is enough data before accessing it */
691	if (!pskb_may_pull(skb, hdr_len + ETH_HLEN))
692		return 0;
693
694	/* create a copy of the skb (in case of for re-routing) to modify it. */
695	if (skb_cow(skb, sizeof(*unicast_packet)) < 0)
696		return 0;
697
698	unicast_packet = (struct batadv_unicast_packet *)skb->data;
699	vid = batadv_get_vid(skb, hdr_len);
700	ethhdr = (struct ethhdr *)(skb->data + hdr_len);
701
702	/* check if the destination client was served by this node and it is now
703	 * roaming. In this case, it means that the node has got a ROAM_ADV
704	 * message and that it knows the new destination in the mesh to re-route
705	 * the packet to
706	 */
707	if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest, vid)) {
708		if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
709						  ethhdr->h_dest, vid))
710			batadv_dbg_ratelimited(BATADV_DBG_TT,
711					       bat_priv,
712					       "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n",
713					       unicast_packet->dest,
714					       ethhdr->h_dest);
715		/* at this point the mesh destination should have been
716		 * substituted with the originator address found in the global
717		 * table. If not, let the packet go untouched anyway because
718		 * there is nothing the node can do
719		 */
720		return 1;
721	}
722
723	/* retrieve the TTVN known by this node for the packet destination. This
724	 * value is used later to check if the node which sent (or re-routed
725	 * last time) the packet had an updated information or not
726	 */
727	curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn);
728	if (!batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
729		orig_node = batadv_orig_hash_find(bat_priv,
730						  unicast_packet->dest);
731		/* if it is not possible to find the orig_node representing the
732		 * destination, the packet can immediately be dropped as it will
733		 * not be possible to deliver it
734		 */
735		if (!orig_node)
736			return 0;
737
738		curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
739		batadv_orig_node_free_ref(orig_node);
740	}
741
742	/* check if the TTVN contained in the packet is fresher than what the
743	 * node knows
744	 */
745	is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn);
746	if (!is_old_ttvn)
747		return 1;
748
749	old_ttvn = unicast_packet->ttvn;
750	/* the packet was forged based on outdated network information. Its
751	 * destination can possibly be updated and forwarded towards the new
752	 * target host
753	 */
754	if (batadv_reroute_unicast_packet(bat_priv, unicast_packet,
755					  ethhdr->h_dest, vid)) {
756		batadv_dbg_ratelimited(BATADV_DBG_TT, bat_priv,
757				       "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n",
758				       unicast_packet->dest, ethhdr->h_dest,
759				       old_ttvn, curr_ttvn);
760		return 1;
761	}
762
763	/* the packet has not been re-routed: either the destination is
764	 * currently served by this node or there is no destination at all and
765	 * it is possible to drop the packet
766	 */
767	if (!batadv_is_my_client(bat_priv, ethhdr->h_dest, vid))
768		return 0;
769
770	/* update the header in order to let the packet be delivered to this
771	 * node's soft interface
772	 */
773	primary_if = batadv_primary_if_get_selected(bat_priv);
774	if (!primary_if)
775		return 0;
776
777	ether_addr_copy(unicast_packet->dest, primary_if->net_dev->dev_addr);
778
779	batadv_hardif_free_ref(primary_if);
780
781	unicast_packet->ttvn = curr_ttvn;
782
783	return 1;
784}
785
786/**
787 * batadv_recv_unhandled_unicast_packet - receive and process packets which
788 *	are in the unicast number space but not yet known to the implementation
789 * @skb: unicast tvlv packet to process
790 * @recv_if: pointer to interface this packet was received on
791 *
792 * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
793 * otherwise.
794 */
795int batadv_recv_unhandled_unicast_packet(struct sk_buff *skb,
796					 struct batadv_hard_iface *recv_if)
797{
798	struct batadv_unicast_packet *unicast_packet;
799	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
800	int check, hdr_size = sizeof(*unicast_packet);
801
802	check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
803	if (check < 0)
804		return NET_RX_DROP;
805
806	/* we don't know about this type, drop it. */
807	unicast_packet = (struct batadv_unicast_packet *)skb->data;
808	if (batadv_is_my_mac(bat_priv, unicast_packet->dest))
809		return NET_RX_DROP;
810
811	return batadv_route_unicast_packet(skb, recv_if);
812}
813
814int batadv_recv_unicast_packet(struct sk_buff *skb,
815			       struct batadv_hard_iface *recv_if)
816{
817	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
818	struct batadv_unicast_packet *unicast_packet;
819	struct batadv_unicast_4addr_packet *unicast_4addr_packet;
820	uint8_t *orig_addr;
821	struct batadv_orig_node *orig_node = NULL;
822	int check, hdr_size = sizeof(*unicast_packet);
823	bool is4addr;
824
825	unicast_packet = (struct batadv_unicast_packet *)skb->data;
826	unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
827
828	is4addr = unicast_packet->packet_type == BATADV_UNICAST_4ADDR;
829	/* the caller function should have already pulled 2 bytes */
830	if (is4addr)
831		hdr_size = sizeof(*unicast_4addr_packet);
832
833	/* function returns -EREMOTE for promiscuous packets */
834	check = batadv_check_unicast_packet(bat_priv, skb, hdr_size);
835
836	/* Even though the packet is not for us, we might save it to use for
837	 * decoding a later received coded packet
838	 */
839	if (check == -EREMOTE)
840		batadv_nc_skb_store_sniffed_unicast(bat_priv, skb);
841
842	if (check < 0)
843		return NET_RX_DROP;
844	if (!batadv_check_unicast_ttvn(bat_priv, skb, hdr_size))
845		return NET_RX_DROP;
846
847	/* packet for me */
848	if (batadv_is_my_mac(bat_priv, unicast_packet->dest)) {
849		if (is4addr) {
850			batadv_dat_inc_counter(bat_priv,
851					       unicast_4addr_packet->subtype);
852			orig_addr = unicast_4addr_packet->src;
853			orig_node = batadv_orig_hash_find(bat_priv, orig_addr);
854		}
855
856		if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb,
857							  hdr_size))
858			goto rx_success;
859		if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb,
860							hdr_size))
861			goto rx_success;
862
863		batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
864				    orig_node);
865
866rx_success:
867		if (orig_node)
868			batadv_orig_node_free_ref(orig_node);
869
870		return NET_RX_SUCCESS;
871	}
872
873	return batadv_route_unicast_packet(skb, recv_if);
874}
875
876/**
877 * batadv_recv_unicast_tvlv - receive and process unicast tvlv packets
878 * @skb: unicast tvlv packet to process
879 * @recv_if: pointer to interface this packet was received on
880 * @dst_addr: the payload destination
881 *
882 * Returns NET_RX_SUCCESS if the packet has been consumed or NET_RX_DROP
883 * otherwise.
884 */
885int batadv_recv_unicast_tvlv(struct sk_buff *skb,
886			     struct batadv_hard_iface *recv_if)
887{
888	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
889	struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
890	unsigned char *tvlv_buff;
891	uint16_t tvlv_buff_len;
892	int hdr_size = sizeof(*unicast_tvlv_packet);
893	int ret = NET_RX_DROP;
894
895	if (batadv_check_unicast_packet(bat_priv, skb, hdr_size) < 0)
896		return NET_RX_DROP;
897
898	/* the header is likely to be modified while forwarding */
899	if (skb_cow(skb, hdr_size) < 0)
900		return NET_RX_DROP;
901
902	/* packet needs to be linearized to access the tvlv content */
903	if (skb_linearize(skb) < 0)
904		return NET_RX_DROP;
905
906	unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)skb->data;
907
908	tvlv_buff = (unsigned char *)(skb->data + hdr_size);
909	tvlv_buff_len = ntohs(unicast_tvlv_packet->tvlv_len);
910
911	if (tvlv_buff_len > skb->len - hdr_size)
912		return NET_RX_DROP;
913
914	ret = batadv_tvlv_containers_process(bat_priv, false, NULL,
915					     unicast_tvlv_packet->src,
916					     unicast_tvlv_packet->dst,
917					     tvlv_buff, tvlv_buff_len);
918
919	if (ret != NET_RX_SUCCESS)
920		ret = batadv_route_unicast_packet(skb, recv_if);
921	else
922		consume_skb(skb);
923
924	return ret;
925}
926
927/**
928 * batadv_recv_frag_packet - process received fragment
929 * @skb: the received fragment
930 * @recv_if: interface that the skb is received on
931 *
932 * This function does one of the three following things: 1) Forward fragment, if
933 * the assembled packet will exceed our MTU; 2) Buffer fragment, if we till
934 * lack further fragments; 3) Merge fragments, if we have all needed parts.
935 *
936 * Return NET_RX_DROP if the skb is not consumed, NET_RX_SUCCESS otherwise.
937 */
938int batadv_recv_frag_packet(struct sk_buff *skb,
939			    struct batadv_hard_iface *recv_if)
940{
941	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
942	struct batadv_orig_node *orig_node_src = NULL;
943	struct batadv_frag_packet *frag_packet;
944	int ret = NET_RX_DROP;
945
946	if (batadv_check_unicast_packet(bat_priv, skb,
947					sizeof(*frag_packet)) < 0)
948		goto out;
949
950	frag_packet = (struct batadv_frag_packet *)skb->data;
951	orig_node_src = batadv_orig_hash_find(bat_priv, frag_packet->orig);
952	if (!orig_node_src)
953		goto out;
954
955	/* Route the fragment if it is not for us and too big to be merged. */
956	if (!batadv_is_my_mac(bat_priv, frag_packet->dest) &&
957	    batadv_frag_skb_fwd(skb, recv_if, orig_node_src)) {
958		ret = NET_RX_SUCCESS;
959		goto out;
960	}
961
962	batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX);
963	batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len);
964
965	/* Add fragment to buffer and merge if possible. */
966	if (!batadv_frag_skb_buffer(&skb, orig_node_src))
967		goto out;
968
969	/* Deliver merged packet to the appropriate handler, if it was
970	 * merged
971	 */
972	if (skb)
973		batadv_batman_skb_recv(skb, recv_if->net_dev,
974				       &recv_if->batman_adv_ptype, NULL);
975
976	ret = NET_RX_SUCCESS;
977
978out:
979	if (orig_node_src)
980		batadv_orig_node_free_ref(orig_node_src);
981
982	return ret;
983}
984
985int batadv_recv_bcast_packet(struct sk_buff *skb,
986			     struct batadv_hard_iface *recv_if)
987{
988	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
989	struct batadv_orig_node *orig_node = NULL;
990	struct batadv_bcast_packet *bcast_packet;
991	struct ethhdr *ethhdr;
992	int hdr_size = sizeof(*bcast_packet);
993	int ret = NET_RX_DROP;
994	int32_t seq_diff;
995	uint32_t seqno;
996
997	/* drop packet if it has not necessary minimum size */
998	if (unlikely(!pskb_may_pull(skb, hdr_size)))
999		goto out;
1000
1001	ethhdr = eth_hdr(skb);
1002
1003	/* packet with broadcast indication but unicast recipient */
1004	if (!is_broadcast_ether_addr(ethhdr->h_dest))
1005		goto out;
1006
1007	/* packet with broadcast sender address */
1008	if (is_broadcast_ether_addr(ethhdr->h_source))
1009		goto out;
1010
1011	/* ignore broadcasts sent by myself */
1012	if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
1013		goto out;
1014
1015	bcast_packet = (struct batadv_bcast_packet *)skb->data;
1016
1017	/* ignore broadcasts originated by myself */
1018	if (batadv_is_my_mac(bat_priv, bcast_packet->orig))
1019		goto out;
1020
1021	if (bcast_packet->ttl < 2)
1022		goto out;
1023
1024	orig_node = batadv_orig_hash_find(bat_priv, bcast_packet->orig);
1025
1026	if (!orig_node)
1027		goto out;
1028
1029	spin_lock_bh(&orig_node->bcast_seqno_lock);
1030
1031	seqno = ntohl(bcast_packet->seqno);
1032	/* check whether the packet is a duplicate */
1033	if (batadv_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
1034			    seqno))
1035		goto spin_unlock;
1036
1037	seq_diff = seqno - orig_node->last_bcast_seqno;
1038
1039	/* check whether the packet is old and the host just restarted. */
1040	if (batadv_window_protected(bat_priv, seq_diff,
1041				    &orig_node->bcast_seqno_reset))
1042		goto spin_unlock;
1043
1044	/* mark broadcast in flood history, update window position
1045	 * if required.
1046	 */
1047	if (batadv_bit_get_packet(bat_priv, orig_node->bcast_bits, seq_diff, 1))
1048		orig_node->last_bcast_seqno = seqno;
1049
1050	spin_unlock_bh(&orig_node->bcast_seqno_lock);
1051
1052	/* check whether this has been sent by another originator before */
1053	if (batadv_bla_check_bcast_duplist(bat_priv, skb))
1054		goto out;
1055
1056	batadv_skb_set_priority(skb, sizeof(struct batadv_bcast_packet));
1057
1058	/* rebroadcast packet */
1059	batadv_add_bcast_packet_to_list(bat_priv, skb, 1);
1060
1061	/* don't hand the broadcast up if it is from an originator
1062	 * from the same backbone.
1063	 */
1064	if (batadv_bla_is_backbone_gw(skb, orig_node, hdr_size))
1065		goto out;
1066
1067	if (batadv_dat_snoop_incoming_arp_request(bat_priv, skb, hdr_size))
1068		goto rx_success;
1069	if (batadv_dat_snoop_incoming_arp_reply(bat_priv, skb, hdr_size))
1070		goto rx_success;
1071
1072	/* broadcast for me */
1073	batadv_interface_rx(recv_if->soft_iface, skb, recv_if, hdr_size,
1074			    orig_node);
1075
1076rx_success:
1077	ret = NET_RX_SUCCESS;
1078	goto out;
1079
1080spin_unlock:
1081	spin_unlock_bh(&orig_node->bcast_seqno_lock);
1082out:
1083	if (orig_node)
1084		batadv_orig_node_free_ref(orig_node);
1085	return ret;
1086}
1087