summaryrefslogtreecommitdiff
path: root/net/batman-adv/bat_v_elp.c
blob: d35aca0e969a9196bc14f005c5311bbbb99b5181 (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
// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2011-2020  B.A.T.M.A.N. contributors:
 *
 * Linus Lüssing, Marek Lindner
 */

#include "bat_v_elp.h"
#include "main.h"

#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/byteorder/generic.h>
#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/gfp.h>
#include <linux/if_ether.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/netdevice.h>
#include <linux/nl80211.h>
#include <linux/random.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <net/cfg80211.h>
#include <uapi/linux/batadv_packet.h>

#include "bat_algo.h"
#include "bat_v_ogm.h"
#include "hard-interface.h"
#include "log.h"
#include "originator.h"
#include "routing.h"
#include "send.h"

/**
 * batadv_v_elp_start_timer() - restart timer for ELP periodic work
 * @hard_iface: the interface for which the timer has to be reset
 */
static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
{
	unsigned int msecs;

	msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
	msecs += prandom_u32_max(2 * BATADV_JITTER);

	queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
			   msecs_to_jiffies(msecs));
}

/**
 * batadv_v_elp_get_throughput() - get the throughput towards a neighbour
 * @neigh: the neighbour for which the throughput has to be obtained
 *
 * Return: The throughput towards the given neighbour in multiples of 100kpbs
 *         (a value of '1' equals 0.1Mbps, '10' equals 1Mbps, etc).
 */
static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
{
	struct batadv_hard_iface *hard_iface = neigh->if_incoming;
	struct ethtool_link_ksettings link_settings;
	struct net_device *real_netdev;
	struct station_info sinfo;
	u32 throughput;
	int ret;

	/* if the user specified a customised value for this interface, then
	 * return it directly
	 */
	throughput =  atomic_read(&hard_iface->bat_v.throughput_override);
	if (throughput != 0)
		return throughput;

	/* if this is a wireless device, then ask its throughput through
	 * cfg80211 API
	 */
	if (batadv_is_wifi_hardif(hard_iface)) {
		if (!batadv_is_cfg80211_hardif(hard_iface))
			/* unsupported WiFi driver version */
			goto default_throughput;

		real_netdev = batadv_get_real_netdev(hard_iface->net_dev);
		if (!real_netdev)
			goto default_throughput;

		ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo);

		if (!ret) {
			/* free the TID stats immediately */
			cfg80211_sinfo_release_content(&sinfo);
		}

		dev_put(real_netdev);
		if (ret == -ENOENT) {
			/* Node is not associated anymore! It would be
			 * possible to delete this neighbor. For now set
			 * the throughput metric to 0.
			 */
			return 0;
		}
		if (ret)
			goto default_throughput;

		if (sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT))
			return sinfo.expected_throughput / 100;

		/* try to estimate the expected throughput based on reported tx
		 * rates
		 */
		if (sinfo.filled & BIT(NL80211_STA_INFO_TX_BITRATE))
			return cfg80211_calculate_bitrate(&sinfo.txrate) / 3;

		goto default_throughput;
	}

	/* if not a wifi interface, check if this device provides data via
	 * ethtool (e.g. an Ethernet adapter)
	 */
	memset(&link_settings, 0, sizeof(link_settings));
	rtnl_lock();
	ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
	rtnl_unlock();
	if (ret == 0) {
		/* link characteristics might change over time */
		if (link_settings.base.duplex == DUPLEX_FULL)
			hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
		else
			hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;

		throughput = link_settings.base.speed;
		if (throughput && throughput != SPEED_UNKNOWN)
			return throughput * 10;
	}

default_throughput:
	if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
		batadv_info(hard_iface->soft_iface,
			    "WiFi driver or ethtool info does not provide information about link speeds on interface %s, therefore defaulting to hardcoded throughput values of %u.%1u Mbps. Consider overriding the throughput manually or checking your driver.\n",
			    hard_iface->net_dev->name,
			    BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
			    BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
		hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
	}

	/* if none of the above cases apply, return the base_throughput */
	return BATADV_THROUGHPUT_DEFAULT_VALUE;
}

/**
 * batadv_v_elp_throughput_metric_update() - worker updating the throughput
 *  metric of a single hop neighbour
 * @work: the work queue item
 */
void batadv_v_elp_throughput_metric_update(struct work_struct *work)
{
	struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
	struct batadv_hardif_neigh_node *neigh;

	neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
				   metric_work);
	neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
			     bat_v);

	ewma_throughput_add(&neigh->bat_v.throughput,
			    batadv_v_elp_get_throughput(neigh));

	/* decrement refcounter to balance increment performed before scheduling
	 * this task
	 */
	batadv_hardif_neigh_put(neigh);
}

/**
 * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
 * @neigh: the neighbour to probe
 *
 * Sends a predefined number of unicast wifi packets to a given neighbour in
 * order to trigger the throughput estimation on this link by the RC algorithm.
 * Packets are sent only if there is not enough payload unicast traffic towards
 * this neighbour..
 *
 * Return: True on success and false in case of error during skb preparation.
 */
static bool
batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
{
	struct batadv_hard_iface *hard_iface = neigh->if_incoming;
	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
	unsigned long last_tx_diff;
	struct sk_buff *skb;
	int probe_len, i;
	int elp_skb_len;

	/* this probing routine is for Wifi neighbours only */
	if (!batadv_is_wifi_hardif(hard_iface))
		return true;

	/* probe the neighbor only if no unicast packets have been sent
	 * to it in the last 100 milliseconds: this is the rate control
	 * algorithm sampling interval (minstrel). In this way, if not
	 * enough traffic has been sent to the neighbor, batman-adv can
	 * generate 2 probe packets and push the RC algorithm to perform
	 * the sampling
	 */
	last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
	if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
		return true;

	probe_len = max_t(int, sizeof(struct batadv_elp_packet),
			  BATADV_ELP_MIN_PROBE_SIZE);

	for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
		elp_skb_len = hard_iface->bat_v.elp_skb->len;
		skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
				      probe_len - elp_skb_len,
				      GFP_ATOMIC);
		if (!skb)
			return false;

		/* Tell the skb to get as big as the allocated space (we want
		 * the packet to be exactly of that size to make the link
		 * throughput estimation effective.
		 */
		skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);

		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
			   "Sending unicast (probe) ELP packet on interface %s to %pM\n",
			   hard_iface->net_dev->name, neigh->addr);

		batadv_send_skb_packet(skb, hard_iface, neigh->addr);
	}

	return true;
}

/**
 * batadv_v_elp_periodic_work() - ELP periodic task per interface
 * @work: work queue item
 *
 * Emits broadcast ELP messages in regular intervals.
 */
static void batadv_v_elp_periodic_work(struct work_struct *work)
{
	struct batadv_hardif_neigh_node *hardif_neigh;
	struct batadv_hard_iface *hard_iface;
	struct batadv_hard_iface_bat_v *bat_v;
	struct batadv_elp_packet *elp_packet;
	struct batadv_priv *bat_priv;
	struct sk_buff *skb;
	u32 elp_interval;
	bool ret;

	bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
	hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
	bat_priv = netdev_priv(hard_iface->soft_iface);

	if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
		goto out;

	/* we are in the process of shutting this interface down */
	if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
	    hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
		goto out;

	/* the interface was enabled but may not be ready yet */
	if (hard_iface->if_status != BATADV_IF_ACTIVE)
		goto restart_timer;

	skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
	if (!skb)
		goto restart_timer;

	elp_packet = (struct batadv_elp_packet *)skb->data;
	elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
	elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
	elp_packet->elp_interval = htonl(elp_interval);

	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
		   "Sending broadcast ELP packet on interface %s, seqno %u\n",
		   hard_iface->net_dev->name,
		   atomic_read(&hard_iface->bat_v.elp_seqno));

	batadv_send_broadcast_skb(skb, hard_iface);

	atomic_inc(&hard_iface->bat_v.elp_seqno);

	/* The throughput metric is updated on each sent packet. This way, if a
	 * node is dead and no longer sends packets, batman-adv is still able to
	 * react timely to its death.
	 *
	 * The throughput metric is updated by following these steps:
	 * 1) if the hard_iface is wifi => send a number of unicast ELPs for
	 *    probing/sampling to each neighbor
	 * 2) update the throughput metric value of each neighbor (note that the
	 *    value retrieved in this step might be 100ms old because the
	 *    probing packets at point 1) could still be in the HW queue)
	 */
	rcu_read_lock();
	hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
		if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
			/* if something goes wrong while probing, better to stop
			 * sending packets immediately and reschedule the task
			 */
			break;

		if (!kref_get_unless_zero(&hardif_neigh->refcount))
			continue;

		/* Reading the estimated throughput from cfg80211 is a task that
		 * may sleep and that is not allowed in an rcu protected
		 * context. Therefore schedule a task for that.
		 */
		ret = queue_work(batadv_event_workqueue,
				 &hardif_neigh->bat_v.metric_work);

		if (!ret)
			batadv_hardif_neigh_put(hardif_neigh);
	}
	rcu_read_unlock();

restart_timer:
	batadv_v_elp_start_timer(hard_iface);
out:
	return;
}

/**
 * batadv_v_elp_iface_enable() - setup the ELP interface private resources
 * @hard_iface: interface for which the data has to be prepared
 *
 * Return: 0 on success or a -ENOMEM in case of failure.
 */
int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
{
	static const size_t tvlv_padding = sizeof(__be32);
	struct batadv_elp_packet *elp_packet;
	unsigned char *elp_buff;
	u32 random_seqno;
	size_t size;
	int res = -ENOMEM;

	size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
	hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
	if (!hard_iface->bat_v.elp_skb)
		goto out;

	skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
	elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
				BATADV_ELP_HLEN + tvlv_padding);
	elp_packet = (struct batadv_elp_packet *)elp_buff;

	elp_packet->packet_type = BATADV_ELP;
	elp_packet->version = BATADV_COMPAT_VERSION;

	/* randomize initial seqno to avoid collision */
	get_random_bytes(&random_seqno, sizeof(random_seqno));
	atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);

	/* assume full-duplex by default */
	hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;

	/* warn the user (again) if there is no throughput data is available */
	hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;

	if (batadv_is_wifi_hardif(hard_iface))
		hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;

	INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
			  batadv_v_elp_periodic_work);
	batadv_v_elp_start_timer(hard_iface);
	res = 0;

out:
	return res;
}

/**
 * batadv_v_elp_iface_disable() - release ELP interface private resources
 * @hard_iface: interface for which the resources have to be released
 */
void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
{
	cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);

	dev_kfree_skb(hard_iface->bat_v.elp_skb);
	hard_iface->bat_v.elp_skb = NULL;
}

/**
 * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
 *  hard-interface
 * @primary_iface: the new primary interface
 * @hard_iface: interface holding the to-be-updated buffer
 */
void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
				 struct batadv_hard_iface *hard_iface)
{
	struct batadv_elp_packet *elp_packet;
	struct sk_buff *skb;

	if (!hard_iface->bat_v.elp_skb)
		return;

	skb = hard_iface->bat_v.elp_skb;
	elp_packet = (struct batadv_elp_packet *)skb->data;
	ether_addr_copy(elp_packet->orig,
			primary_iface->net_dev->dev_addr);
}

/**
 * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
 *  primary interface
 * @primary_iface: the new primary interface
 */
void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
{
	struct batadv_hard_iface *hard_iface;

	/* update orig field of every elp iface belonging to this mesh */
	rcu_read_lock();
	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
		if (primary_iface->soft_iface != hard_iface->soft_iface)
			continue;

		batadv_v_elp_iface_activate(primary_iface, hard_iface);
	}
	rcu_read_unlock();
}

/**
 * batadv_v_elp_neigh_update() - update an ELP neighbour node
 * @bat_priv: the bat priv with all the soft interface information
 * @neigh_addr: the neighbour interface address
 * @if_incoming: the interface the packet was received through
 * @elp_packet: the received ELP packet
 *
 * Updates the ELP neighbour node state with the data received within the new
 * ELP packet.
 */
static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
				      u8 *neigh_addr,
				      struct batadv_hard_iface *if_incoming,
				      struct batadv_elp_packet *elp_packet)

{
	struct batadv_neigh_node *neigh;
	struct batadv_orig_node *orig_neigh;
	struct batadv_hardif_neigh_node *hardif_neigh;
	s32 seqno_diff;
	s32 elp_latest_seqno;

	orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
	if (!orig_neigh)
		return;

	neigh = batadv_neigh_node_get_or_create(orig_neigh,
						if_incoming, neigh_addr);
	if (!neigh)
		goto orig_free;

	hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
	if (!hardif_neigh)
		goto neigh_free;

	elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
	seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;

	/* known or older sequence numbers are ignored. However always adopt
	 * if the router seems to have been restarted.
	 */
	if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
		goto hardif_free;

	neigh->last_seen = jiffies;
	hardif_neigh->last_seen = jiffies;
	hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
	hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);

hardif_free:
	if (hardif_neigh)
		batadv_hardif_neigh_put(hardif_neigh);
neigh_free:
	if (neigh)
		batadv_neigh_node_put(neigh);
orig_free:
	if (orig_neigh)
		batadv_orig_node_put(orig_neigh);
}

/**
 * batadv_v_elp_packet_recv() - main ELP packet handler
 * @skb: the received packet
 * @if_incoming: the interface this packet was received through
 *
 * Return: NET_RX_SUCCESS and consumes the skb if the packet was properly
 * processed or NET_RX_DROP in case of failure.
 */
int batadv_v_elp_packet_recv(struct sk_buff *skb,
			     struct batadv_hard_iface *if_incoming)
{
	struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
	struct batadv_elp_packet *elp_packet;
	struct batadv_hard_iface *primary_if;
	struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
	bool res;
	int ret = NET_RX_DROP;

	res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
	if (!res)
		goto free_skb;

	if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
		goto free_skb;

	/* did we receive a B.A.T.M.A.N. V ELP packet on an interface
	 * that does not have B.A.T.M.A.N. V ELP enabled ?
	 */
	if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
		goto free_skb;

	elp_packet = (struct batadv_elp_packet *)skb->data;

	batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
		   "Received ELP packet from %pM seqno %u ORIG: %pM\n",
		   ethhdr->h_source, ntohl(elp_packet->seqno),
		   elp_packet->orig);

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
		goto free_skb;

	batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
				  elp_packet);

	ret = NET_RX_SUCCESS;
	batadv_hardif_put(primary_if);

free_skb:
	if (ret == NET_RX_SUCCESS)
		consume_skb(skb);
	else
		kfree_skb(skb);

	return ret;
}