summaryrefslogtreecommitdiffstats
path: root/net/batman-adv/gateway_client.c
blob: b421cc49d2cd1f83a88b905047df40e2853c4b0b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
/* Copyright (C) 2009-2012 B.A.T.M.A.N. contributors:
 *
 * Marek Lindner
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 */

#include "main.h"
#include "sysfs.h"
#include "gateway_client.h"
#include "gateway_common.h"
#include "hard-interface.h"
#include "originator.h"
#include "translation-table.h"
#include "routing.h"
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/udp.h>
#include <linux/if_vlan.h>

/* This is the offset of the options field in a dhcp packet starting at
 * the beginning of the dhcp header
 */
#define BATADV_DHCP_OPTIONS_OFFSET 240
#define BATADV_DHCP_REQUEST 3

static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node)
{
	if (atomic_dec_and_test(&gw_node->refcount))
		kfree_rcu(gw_node, rcu);
}

static struct batadv_gw_node *
batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
{
	struct batadv_gw_node *gw_node;

	rcu_read_lock();
	gw_node = rcu_dereference(bat_priv->curr_gw);
	if (!gw_node)
		goto out;

	if (!atomic_inc_not_zero(&gw_node->refcount))
		gw_node = NULL;

out:
	rcu_read_unlock();
	return gw_node;
}

struct batadv_orig_node *
batadv_gw_get_selected_orig(struct batadv_priv *bat_priv)
{
	struct batadv_gw_node *gw_node;
	struct batadv_orig_node *orig_node = NULL;

	gw_node = batadv_gw_get_selected_gw_node(bat_priv);
	if (!gw_node)
		goto out;

	rcu_read_lock();
	orig_node = gw_node->orig_node;
	if (!orig_node)
		goto unlock;

	if (!atomic_inc_not_zero(&orig_node->refcount))
		orig_node = NULL;

unlock:
	rcu_read_unlock();
out:
	if (gw_node)
		batadv_gw_node_free_ref(gw_node);
	return orig_node;
}

static void batadv_gw_select(struct batadv_priv *bat_priv,
			     struct batadv_gw_node *new_gw_node)
{
	struct batadv_gw_node *curr_gw_node;

	spin_lock_bh(&bat_priv->gw_list_lock);

	if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
		new_gw_node = NULL;

	curr_gw_node = rcu_dereference_protected(bat_priv->curr_gw, 1);
	rcu_assign_pointer(bat_priv->curr_gw, new_gw_node);

	if (curr_gw_node)
		batadv_gw_node_free_ref(curr_gw_node);

	spin_unlock_bh(&bat_priv->gw_list_lock);
}

void batadv_gw_deselect(struct batadv_priv *bat_priv)
{
	atomic_set(&bat_priv->gw_reselect, 1);
}

static struct batadv_gw_node *
batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
{
	struct batadv_neigh_node *router;
	struct hlist_node *node;
	struct batadv_gw_node *gw_node, *curr_gw = NULL;
	uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
	uint8_t max_tq = 0;
	int down, up;
	struct batadv_orig_node *orig_node;

	rcu_read_lock();
	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
		if (gw_node->deleted)
			continue;

		orig_node = gw_node->orig_node;
		router = batadv_orig_node_get_router(orig_node);
		if (!router)
			continue;

		if (!atomic_inc_not_zero(&gw_node->refcount))
			goto next;

		switch (atomic_read(&bat_priv->gw_sel_class)) {
		case 1: /* fast connection */
			batadv_gw_bandwidth_to_kbit(orig_node->gw_flags,
						    &down, &up);

			tmp_gw_factor = (router->tq_avg * router->tq_avg *
					 down * 100 * 100) /
					 (BATADV_TQ_LOCAL_WINDOW_SIZE *
					  BATADV_TQ_LOCAL_WINDOW_SIZE * 64);

			if ((tmp_gw_factor > max_gw_factor) ||
			    ((tmp_gw_factor == max_gw_factor) &&
			     (router->tq_avg > max_tq))) {
				if (curr_gw)
					batadv_gw_node_free_ref(curr_gw);
				curr_gw = gw_node;
				atomic_inc(&curr_gw->refcount);
			}
			break;

		default: /* 2:  stable connection (use best statistic)
			  * 3:  fast-switch (use best statistic but change as
			  *     soon as a better gateway appears)
			  * XX: late-switch (use best statistic but change as
			  *     soon as a better gateway appears which has
			  *     $routing_class more tq points)
			  */
			if (router->tq_avg > max_tq) {
				if (curr_gw)
					batadv_gw_node_free_ref(curr_gw);
				curr_gw = gw_node;
				atomic_inc(&curr_gw->refcount);
			}
			break;
		}

		if (router->tq_avg > max_tq)
			max_tq = router->tq_avg;

		if (tmp_gw_factor > max_gw_factor)
			max_gw_factor = tmp_gw_factor;

		batadv_gw_node_free_ref(gw_node);

next:
		batadv_neigh_node_free_ref(router);
	}
	rcu_read_unlock();

	return curr_gw;
}

void batadv_gw_election(struct batadv_priv *bat_priv)
{
	struct batadv_gw_node *curr_gw = NULL, *next_gw = NULL;
	struct batadv_neigh_node *router = NULL;
	char gw_addr[18] = { '\0' };

	/* The batman daemon checks here if we already passed a full originator
	 * cycle in order to make sure we don't choose the first gateway we
	 * hear about. This check is based on the daemon's uptime which we
	 * don't have.
	 */
	if (atomic_read(&bat_priv->gw_mode) != BATADV_GW_MODE_CLIENT)
		goto out;

	if (!batadv_atomic_dec_not_zero(&bat_priv->gw_reselect))
		goto out;

	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);

	next_gw = batadv_gw_get_best_gw_node(bat_priv);

	if (curr_gw == next_gw)
		goto out;

	if (next_gw) {
		sprintf(gw_addr, "%pM", next_gw->orig_node->orig);

		router = batadv_orig_node_get_router(next_gw->orig_node);
		if (!router) {
			batadv_gw_deselect(bat_priv);
			goto out;
		}
	}

	if ((curr_gw) && (!next_gw)) {
		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
			   "Removing selected gateway - no gateway in range\n");
		batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_DEL,
				    NULL);
	} else if ((!curr_gw) && (next_gw)) {
		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
			   "Adding route to gateway %pM (gw_flags: %i, tq: %i)\n",
			   next_gw->orig_node->orig,
			   next_gw->orig_node->gw_flags, router->tq_avg);
		batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_ADD,
				    gw_addr);
	} else {
		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
			   "Changing route to gateway %pM (gw_flags: %i, tq: %i)\n",
			   next_gw->orig_node->orig,
			   next_gw->orig_node->gw_flags, router->tq_avg);
		batadv_throw_uevent(bat_priv, BATADV_UEV_GW, BATADV_UEV_CHANGE,
				    gw_addr);
	}

	batadv_gw_select(bat_priv, next_gw);

out:
	if (curr_gw)
		batadv_gw_node_free_ref(curr_gw);
	if (next_gw)
		batadv_gw_node_free_ref(next_gw);
	if (router)
		batadv_neigh_node_free_ref(router);
}

void batadv_gw_check_election(struct batadv_priv *bat_priv,
			      struct batadv_orig_node *orig_node)
{
	struct batadv_orig_node *curr_gw_orig;
	struct batadv_neigh_node *router_gw = NULL, *router_orig = NULL;
	uint8_t gw_tq_avg, orig_tq_avg;

	curr_gw_orig = batadv_gw_get_selected_orig(bat_priv);
	if (!curr_gw_orig)
		goto deselect;

	router_gw = batadv_orig_node_get_router(curr_gw_orig);
	if (!router_gw)
		goto deselect;

	/* this node already is the gateway */
	if (curr_gw_orig == orig_node)
		goto out;

	router_orig = batadv_orig_node_get_router(orig_node);
	if (!router_orig)
		goto out;

	gw_tq_avg = router_gw->tq_avg;
	orig_tq_avg = router_orig->tq_avg;

	/* the TQ value has to be better */
	if (orig_tq_avg < gw_tq_avg)
		goto out;

	/* if the routing class is greater than 3 the value tells us how much
	 * greater the TQ value of the new gateway must be
	 */
	if ((atomic_read(&bat_priv->gw_sel_class) > 3) &&
	    (orig_tq_avg - gw_tq_avg < atomic_read(&bat_priv->gw_sel_class)))
		goto out;

	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
		   "Restarting gateway selection: better gateway found (tq curr: %i, tq new: %i)\n",
		   gw_tq_avg, orig_tq_avg);

deselect:
	batadv_gw_deselect(bat_priv);
out:
	if (curr_gw_orig)
		batadv_orig_node_free_ref(curr_gw_orig);
	if (router_gw)
		batadv_neigh_node_free_ref(router_gw);
	if (router_orig)
		batadv_neigh_node_free_ref(router_orig);

	return;
}

static void batadv_gw_node_add(struct batadv_priv *bat_priv,
			       struct batadv_orig_node *orig_node,
			       uint8_t new_gwflags)
{
	struct batadv_gw_node *gw_node;
	int down, up;

	gw_node = kzalloc(sizeof(*gw_node), GFP_ATOMIC);
	if (!gw_node)
		return;

	INIT_HLIST_NODE(&gw_node->list);
	gw_node->orig_node = orig_node;
	atomic_set(&gw_node->refcount, 1);

	spin_lock_bh(&bat_priv->gw_list_lock);
	hlist_add_head_rcu(&gw_node->list, &bat_priv->gw_list);
	spin_unlock_bh(&bat_priv->gw_list_lock);

	batadv_gw_bandwidth_to_kbit(new_gwflags, &down, &up);
	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
		   "Found new gateway %pM -> gw_class: %i - %i%s/%i%s\n",
		   orig_node->orig, new_gwflags,
		   (down > 2048 ? down / 1024 : down),
		   (down > 2048 ? "MBit" : "KBit"),
		   (up > 2048 ? up / 1024 : up),
		   (up > 2048 ? "MBit" : "KBit"));
}

void batadv_gw_node_update(struct batadv_priv *bat_priv,
			   struct batadv_orig_node *orig_node,
			   uint8_t new_gwflags)
{
	struct hlist_node *node;
	struct batadv_gw_node *gw_node, *curr_gw;

	/* Note: We don't need a NULL check here, since curr_gw never gets
	 * dereferenced. If curr_gw is NULL we also should not exit as we may
	 * have this gateway in our list (duplication check!) even though we
	 * have no currently selected gateway.
	 */
	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);

	rcu_read_lock();
	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
		if (gw_node->orig_node != orig_node)
			continue;

		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
			   "Gateway class of originator %pM changed from %i to %i\n",
			   orig_node->orig, gw_node->orig_node->gw_flags,
			   new_gwflags);

		gw_node->deleted = 0;

		if (new_gwflags == BATADV_NO_FLAGS) {
			gw_node->deleted = jiffies;
			batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
				   "Gateway %pM removed from gateway list\n",
				   orig_node->orig);

			if (gw_node == curr_gw)
				goto deselect;
		}

		goto unlock;
	}

	if (new_gwflags == BATADV_NO_FLAGS)
		goto unlock;

	batadv_gw_node_add(bat_priv, orig_node, new_gwflags);
	goto unlock;

deselect:
	batadv_gw_deselect(bat_priv);
unlock:
	rcu_read_unlock();

	if (curr_gw)
		batadv_gw_node_free_ref(curr_gw);
}

void batadv_gw_node_delete(struct batadv_priv *bat_priv,
			   struct batadv_orig_node *orig_node)
{
	batadv_gw_node_update(bat_priv, orig_node, 0);
}

void batadv_gw_node_purge(struct batadv_priv *bat_priv)
{
	struct batadv_gw_node *gw_node, *curr_gw;
	struct hlist_node *node, *node_tmp;
	unsigned long timeout = msecs_to_jiffies(2 * BATADV_PURGE_TIMEOUT);
	int do_deselect = 0;

	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);

	spin_lock_bh(&bat_priv->gw_list_lock);

	hlist_for_each_entry_safe(gw_node, node, node_tmp,
				  &bat_priv->gw_list, list) {
		if (((!gw_node->deleted) ||
		     (time_before(jiffies, gw_node->deleted + timeout))) &&
		    atomic_read(&bat_priv->mesh_state) == BATADV_MESH_ACTIVE)
			continue;

		if (curr_gw == gw_node)
			do_deselect = 1;

		hlist_del_rcu(&gw_node->list);
		batadv_gw_node_free_ref(gw_node);
	}

	spin_unlock_bh(&bat_priv->gw_list_lock);

	/* gw_deselect() needs to acquire the gw_list_lock */
	if (do_deselect)
		batadv_gw_deselect(bat_priv);

	if (curr_gw)
		batadv_gw_node_free_ref(curr_gw);
}

/* fails if orig_node has no router */
static int batadv_write_buffer_text(struct batadv_priv *bat_priv,
				    struct seq_file *seq,
				    const struct batadv_gw_node *gw_node)
{
	struct batadv_gw_node *curr_gw;
	struct batadv_neigh_node *router;
	int down, up, ret = -1;

	batadv_gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up);

	router = batadv_orig_node_get_router(gw_node->orig_node);
	if (!router)
		goto out;

	curr_gw = batadv_gw_get_selected_gw_node(bat_priv);

	ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n",
			 (curr_gw == gw_node ? "=>" : "  "),
			 gw_node->orig_node->orig,
			 router->tq_avg, router->addr,
			 router->if_incoming->net_dev->name,
			 gw_node->orig_node->gw_flags,
			 (down > 2048 ? down / 1024 : down),
			 (down > 2048 ? "MBit" : "KBit"),
			 (up > 2048 ? up / 1024 : up),
			 (up > 2048 ? "MBit" : "KBit"));

	batadv_neigh_node_free_ref(router);
	if (curr_gw)
		batadv_gw_node_free_ref(curr_gw);
out:
	return ret;
}

int batadv_gw_client_seq_print_text(struct seq_file *seq, void *offset)
{
	struct net_device *net_dev = (struct net_device *)seq->private;
	struct batadv_priv *bat_priv = netdev_priv(net_dev);
	struct batadv_hard_iface *primary_if;
	struct batadv_gw_node *gw_node;
	struct hlist_node *node;
	int gw_count = 0, ret = 0;

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if) {
		ret = seq_printf(seq,
				 "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
				 net_dev->name);
		goto out;
	}

	if (primary_if->if_status != BATADV_IF_ACTIVE) {
		ret = seq_printf(seq,
				 "BATMAN mesh %s disabled - primary interface not active\n",
				 net_dev->name);
		goto out;
	}

	seq_printf(seq,
		   "      %-12s (%s/%i) %17s [%10s]: gw_class ... [B.A.T.M.A.N. adv %s, MainIF/MAC: %s/%pM (%s)]\n",
		   "Gateway", "#", BATADV_TQ_MAX_VALUE, "Nexthop", "outgoingIF",
		   BATADV_SOURCE_VERSION, primary_if->net_dev->name,
		   primary_if->net_dev->dev_addr, net_dev->name);

	rcu_read_lock();
	hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) {
		if (gw_node->deleted)
			continue;

		/* fails if orig_node has no router */
		if (batadv_write_buffer_text(bat_priv, seq, gw_node) < 0)
			continue;

		gw_count++;
	}
	rcu_read_unlock();

	if (gw_count == 0)
		seq_printf(seq, "No gateways in range ...\n");

out:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
	return ret;
}

static bool batadv_is_type_dhcprequest(struct sk_buff *skb, int header_len)
{
	int ret = false;
	unsigned char *p;
	int pkt_len;

	if (skb_linearize(skb) < 0)
		goto out;

	pkt_len = skb_headlen(skb);

	if (pkt_len < header_len + BATADV_DHCP_OPTIONS_OFFSET + 1)
		goto out;

	p = skb->data + header_len + BATADV_DHCP_OPTIONS_OFFSET;
	pkt_len -= header_len + BATADV_DHCP_OPTIONS_OFFSET + 1;

	/* Access the dhcp option lists. Each entry is made up by:
	 * - octet 1: option type
	 * - octet 2: option data len (only if type != 255 and 0)
	 * - octet 3: option data
	 */
	while (*p != 255 && !ret) {
		/* p now points to the first octet: option type */
		if (*p == 53) {
			/* type 53 is the message type option.
			 * Jump the len octet and go to the data octet
			 */
			if (pkt_len < 2)
				goto out;
			p += 2;

			/* check if the message type is what we need */
			if (*p == BATADV_DHCP_REQUEST)
				ret = true;
			break;
		} else if (*p == 0) {
			/* option type 0 (padding), just go forward */
			if (pkt_len < 1)
				goto out;
			pkt_len--;
			p++;
		} else {
			/* This is any other option. So we get the length... */
			if (pkt_len < 1)
				goto out;
			pkt_len--;
			p++;

			/* ...and then we jump over the data */
			if (pkt_len < 1 + (*p))
				goto out;
			pkt_len -= 1 + (*p);
			p += 1 + (*p);
		}
	}
out:
	return ret;
}

bool batadv_gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len)
{
	struct ethhdr *ethhdr;
	struct iphdr *iphdr;
	struct ipv6hdr *ipv6hdr;
	struct udphdr *udphdr;

	/* check for ethernet header */
	if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
		return false;
	ethhdr = (struct ethhdr *)skb->data;
	*header_len += ETH_HLEN;

	/* check for initial vlan header */
	if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
		if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
			return false;
		ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
		*header_len += VLAN_HLEN;
	}

	/* check for ip header */
	switch (ntohs(ethhdr->h_proto)) {
	case ETH_P_IP:
		if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
			return false;
		iphdr = (struct iphdr *)(skb->data + *header_len);
		*header_len += iphdr->ihl * 4;

		/* check for udp header */
		if (iphdr->protocol != IPPROTO_UDP)
			return false;

		break;
	case ETH_P_IPV6:
		if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
			return false;
		ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
		*header_len += sizeof(*ipv6hdr);

		/* check for udp header */
		if (ipv6hdr->nexthdr != IPPROTO_UDP)
			return false;

		break;
	default:
		return false;
	}

	if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
		return false;
	udphdr = (struct udphdr *)(skb->data + *header_len);
	*header_len += sizeof(*udphdr);

	/* check for bootp port */
	if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
	    (ntohs(udphdr->dest) != 67))
		return false;

	if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
	    (ntohs(udphdr->dest) != 547))
		return false;

	return true;
}

bool batadv_gw_out_of_range(struct batadv_priv *bat_priv,
			    struct sk_buff *skb, struct ethhdr *ethhdr)
{
	struct batadv_neigh_node *neigh_curr = NULL, *neigh_old = NULL;
	struct batadv_orig_node *orig_dst_node = NULL;
	struct batadv_gw_node *curr_gw = NULL;
	bool ret, out_of_range = false;
	unsigned int header_len = 0;
	uint8_t curr_tq_avg;

	ret = batadv_gw_is_dhcp_target(skb, &header_len);
	if (!ret)
		goto out;

	orig_dst_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
						 ethhdr->h_dest);
	if (!orig_dst_node)
		goto out;

	if (!orig_dst_node->gw_flags)
		goto out;

	ret = batadv_is_type_dhcprequest(skb, header_len);
	if (!ret)
		goto out;

	switch (atomic_read(&bat_priv->gw_mode)) {
	case BATADV_GW_MODE_SERVER:
		/* If we are a GW then we are our best GW. We can artificially
		 * set the tq towards ourself as the maximum value
		 */
		curr_tq_avg = BATADV_TQ_MAX_VALUE;
		break;
	case BATADV_GW_MODE_CLIENT:
		curr_gw = batadv_gw_get_selected_gw_node(bat_priv);
		if (!curr_gw)
			goto out;

		/* packet is going to our gateway */
		if (curr_gw->orig_node == orig_dst_node)
			goto out;

		/* If the dhcp packet has been sent to a different gw,
		 * we have to evaluate whether the old gw is still
		 * reliable enough
		 */
		neigh_curr = batadv_find_router(bat_priv, curr_gw->orig_node,
						NULL);
		if (!neigh_curr)
			goto out;

		curr_tq_avg = neigh_curr->tq_avg;
		break;
	case BATADV_GW_MODE_OFF:
	default:
		goto out;
	}

	neigh_old = batadv_find_router(bat_priv, orig_dst_node, NULL);
	if (!neigh_old)
		goto out;

	if (curr_tq_avg - neigh_old->tq_avg > BATADV_GW_THRESHOLD)
		out_of_range = true;

out:
	if (orig_dst_node)
		batadv_orig_node_free_ref(orig_dst_node);
	if (curr_gw)
		batadv_gw_node_free_ref(curr_gw);
	if (neigh_old)
		batadv_neigh_node_free_ref(neigh_old);
	if (neigh_curr)
		batadv_neigh_node_free_ref(neigh_curr);
	return out_of_range;
}
OpenPOWER on IntegriCloud