1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2011-2019 B.A.T.M.A.N. contributors:
3 *
4 * Linus Lüssing, Marek Lindner
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of version 2 of the GNU General Public
8 * License as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, see <http://www.gnu.org/licenses/>.
17 */
18
19 #include "bat_v_elp.h"
20 #include "main.h"
21
22 #include <linux/atomic.h>
23 #include <linux/bitops.h>
24 #include <linux/byteorder/generic.h>
25 #include <linux/errno.h>
26 #include <linux/etherdevice.h>
27 #include <linux/ethtool.h>
28 #include <linux/gfp.h>
29 #include <linux/if_ether.h>
30 #include <linux/jiffies.h>
31 #include <linux/kernel.h>
32 #include <linux/kref.h>
33 #include <linux/netdevice.h>
34 #include <linux/nl80211.h>
35 #include <linux/random.h>
36 #include <linux/rculist.h>
37 #include <linux/rcupdate.h>
38 #include <linux/rtnetlink.h>
39 #include <linux/skbuff.h>
40 #include <linux/stddef.h>
41 #include <linux/string.h>
42 #include <linux/types.h>
43 #include <linux/workqueue.h>
44 #include <net/cfg80211.h>
45 #include <uapi/linux/batadv_packet.h>
46
47 #include "bat_algo.h"
48 #include "bat_v_ogm.h"
49 #include "hard-interface.h"
50 #include "log.h"
51 #include "originator.h"
52 #include "routing.h"
53 #include "send.h"
54
55 /**
56 * batadv_v_elp_start_timer() - restart timer for ELP periodic work
57 * @hard_iface: the interface for which the timer has to be reset
58 */
59 static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
60 {
61 unsigned int msecs;
62
63 msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
64 msecs += prandom_u32() % (2 * BATADV_JITTER);
65
66 queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
67 msecs_to_jiffies(msecs));
68 }
69
70 /**
71 * batadv_v_elp_get_throughput() - get the throughput towards a neighbour
72 * @neigh: the neighbour for which the throughput has to be obtained
73 *
74 * Return: The throughput towards the given neighbour in multiples of 100kpbs
75 * (a value of '1' equals to 0.1Mbps, '10' equals 1Mbps, etc).
76 */
77 static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
78 {
79 struct batadv_hard_iface *hard_iface = neigh->if_incoming;
80 struct ethtool_link_ksettings link_settings;
81 struct net_device *real_netdev;
82 struct station_info sinfo;
83 u32 throughput;
84 int ret;
85
86 /* if the user specified a customised value for this interface, then
87 * return it directly
88 */
89 throughput = atomic_read(&hard_iface->bat_v.throughput_override);
90 if (throughput != 0)
91 return throughput;
92
93 /* if this is a wireless device, then ask its throughput through
94 * cfg80211 API
95 */
96 if (batadv_is_wifi_hardif(hard_iface)) {
97 if (!batadv_is_cfg80211_hardif(hard_iface))
98 /* unsupported WiFi driver version */
99 goto default_throughput;
100
101 real_netdev = batadv_get_real_netdev(hard_iface->net_dev);
102 if (!real_netdev)
103 goto default_throughput;
104
105 ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo);
106
107 if (!ret) {
108 /* free the TID stats immediately */
109 cfg80211_sinfo_release_content(&sinfo);
110 }
111
112 dev_put(real_netdev);
113 if (ret == -ENOENT) {
114 /* Node is not associated anymore! It would be
115 * possible to delete this neighbor. For now set
116 * the throughput metric to 0.
117 */
118 return 0;
119 }
120 if (ret)
121 goto default_throughput;
122 if (!(sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)))
123 goto default_throughput;
124
125 return sinfo.expected_throughput / 100;
126 }
127
128 /* if not a wifi interface, check if this device provides data via
129 * ethtool (e.g. an Ethernet adapter)
130 */
131 memset(&link_settings, 0, sizeof(link_settings));
132 rtnl_lock();
133 ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
134 rtnl_unlock();
135
136 /* Virtual interface drivers such as tun / tap interfaces, VLAN, etc
137 * tend to initialize the interface throughput with some value for the
138 * sake of having a throughput number to export via ethtool. This
139 * exported throughput leaves batman-adv to conclude the interface
140 * throughput is genuine (reflecting reality), thus no measurements
141 * are necessary.
142 *
143 * Based on the observation that those interface types also tend to set
144 * the link auto-negotiation to 'off', batman-adv shall check this
145 * setting to differentiate between genuine link throughput information
146 * and placeholders installed by virtual interfaces.
147 */
148 if (ret == 0 && link_settings.base.autoneg == AUTONEG_ENABLE) {
149 /* link characteristics might change over time */
150 if (link_settings.base.duplex == DUPLEX_FULL)
151 hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
152 else
153 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
154
155 throughput = link_settings.base.speed;
156 if (throughput && throughput != SPEED_UNKNOWN)
157 return throughput * 10;
158 }
159
160 default_throughput:
161 if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
162 batadv_info(hard_iface->soft_iface,
163 "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",
164 hard_iface->net_dev->name,
165 BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
166 BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
167 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
168 }
169
170 /* if none of the above cases apply, return the base_throughput */
171 return BATADV_THROUGHPUT_DEFAULT_VALUE;
172 }
173
174 /**
175 * batadv_v_elp_throughput_metric_update() - worker updating the throughput
176 * metric of a single hop neighbour
177 * @work: the work queue item
178 */
179 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
180 {
181 struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
182 struct batadv_hardif_neigh_node *neigh;
183
184 neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
185 metric_work);
186 neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
187 bat_v);
188
189 ewma_throughput_add(&neigh->bat_v.throughput,
190 batadv_v_elp_get_throughput(neigh));
191
192 /* decrement refcounter to balance increment performed before scheduling
193 * this task
194 */
195 batadv_hardif_neigh_put(neigh);
196 }
197
198 /**
199 * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
200 * @neigh: the neighbour to probe
201 *
202 * Sends a predefined number of unicast wifi packets to a given neighbour in
203 * order to trigger the throughput estimation on this link by the RC algorithm.
204 * Packets are sent only if there there is not enough payload unicast traffic
205 * towards this neighbour..
206 *
207 * Return: True on success and false in case of error during skb preparation.
208 */
209 static bool
210 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
211 {
212 struct batadv_hard_iface *hard_iface = neigh->if_incoming;
213 struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
214 unsigned long last_tx_diff;
215 struct sk_buff *skb;
216 int probe_len, i;
217 int elp_skb_len;
218
219 /* this probing routine is for Wifi neighbours only */
220 if (!batadv_is_wifi_hardif(hard_iface))
221 return true;
222
223 /* probe the neighbor only if no unicast packets have been sent
224 * to it in the last 100 milliseconds: this is the rate control
225 * algorithm sampling interval (minstrel). In this way, if not
226 * enough traffic has been sent to the neighbor, batman-adv can
227 * generate 2 probe packets and push the RC algorithm to perform
228 * the sampling
229 */
230 last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
231 if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
232 return true;
233
234 probe_len = max_t(int, sizeof(struct batadv_elp_packet),
235 BATADV_ELP_MIN_PROBE_SIZE);
236
237 for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
238 elp_skb_len = hard_iface->bat_v.elp_skb->len;
239 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
240 probe_len - elp_skb_len,
241 GFP_ATOMIC);
242 if (!skb)
243 return false;
244
245 /* Tell the skb to get as big as the allocated space (we want
246 * the packet to be exactly of that size to make the link
247 * throughput estimation effective.
248 */
249 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);
250
251 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
252 "Sending unicast (probe) ELP packet on interface %s to %pM\n",
253 hard_iface->net_dev->name, neigh->addr);
254
255 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
256 }
257
258 return true;
259 }
260
261 /**
262 * batadv_v_elp_periodic_work() - ELP periodic task per interface
263 * @work: work queue item
264 *
265 * Emits broadcast ELP message in regular intervals.
266 */
267 static void batadv_v_elp_periodic_work(struct work_struct *work)
268 {
269 struct batadv_hardif_neigh_node *hardif_neigh;
270 struct batadv_hard_iface *hard_iface;
271 struct batadv_hard_iface_bat_v *bat_v;
272 struct batadv_elp_packet *elp_packet;
273 struct batadv_priv *bat_priv;
274 struct sk_buff *skb;
275 u32 elp_interval;
276 bool ret;
277
278 bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
279 hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
280 bat_priv = netdev_priv(hard_iface->soft_iface);
281
282 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
283 goto out;
284
285 /* we are in the process of shutting this interface down */
286 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
287 hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
288 goto out;
289
290 /* the interface was enabled but may not be ready yet */
291 if (hard_iface->if_status != BATADV_IF_ACTIVE)
292 goto restart_timer;
293
294 skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
295 if (!skb)
296 goto restart_timer;
297
298 elp_packet = (struct batadv_elp_packet *)skb->data;
299 elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
300 elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
301 elp_packet->elp_interval = htonl(elp_interval);
302
303 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
304 "Sending broadcast ELP packet on interface %s, seqno %u\n",
305 hard_iface->net_dev->name,
306 atomic_read(&hard_iface->bat_v.elp_seqno));
307
308 batadv_send_broadcast_skb(skb, hard_iface);
309
310 atomic_inc(&hard_iface->bat_v.elp_seqno);
311
312 /* The throughput metric is updated on each sent packet. This way, if a
313 * node is dead and no longer sends packets, batman-adv is still able to
314 * react timely to its death.
315 *
316 * The throughput metric is updated by following these steps:
317 * 1) if the hard_iface is wifi => send a number of unicast ELPs for
318 * probing/sampling to each neighbor
319 * 2) update the throughput metric value of each neighbor (note that the
320 * value retrieved in this step might be 100ms old because the
321 * probing packets at point 1) could still be in the HW queue)
322 */
323 rcu_read_lock();
324 hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
325 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
326 /* if something goes wrong while probing, better to stop
327 * sending packets immediately and reschedule the task
328 */
329 break;
330
331 if (!kref_get_unless_zero(&hardif_neigh->refcount))
332 continue;
333
334 /* Reading the estimated throughput from cfg80211 is a task that
335 * may sleep and that is not allowed in an rcu protected
336 * context. Therefore schedule a task for that.
337 */
338 ret = queue_work(batadv_event_workqueue,
339 &hardif_neigh->bat_v.metric_work);
340
341 if (!ret)
342 batadv_hardif_neigh_put(hardif_neigh);
343 }
344 rcu_read_unlock();
345
346 restart_timer:
347 batadv_v_elp_start_timer(hard_iface);
348 out:
349 return;
350 }
351
352 /**
353 * batadv_v_elp_iface_enable() - setup the ELP interface private resources
354 * @hard_iface: interface for which the data has to be prepared
355 *
356 * Return: 0 on success or a -ENOMEM in case of failure.
357 */
358 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
359 {
360 static const size_t tvlv_padding = sizeof(__be32);
361 struct batadv_elp_packet *elp_packet;
362 unsigned char *elp_buff;
363 u32 random_seqno;
364 size_t size;
365 int res = -ENOMEM;
366
367 size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
368 hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
369 if (!hard_iface->bat_v.elp_skb)
370 goto out;
371
372 skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
373 elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
374 BATADV_ELP_HLEN + tvlv_padding);
375 elp_packet = (struct batadv_elp_packet *)elp_buff;
376
377 elp_packet->packet_type = BATADV_ELP;
378 elp_packet->version = BATADV_COMPAT_VERSION;
379
380 /* randomize initial seqno to avoid collision */
381 get_random_bytes(&random_seqno, sizeof(random_seqno));
382 atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
383
384 /* assume full-duplex by default */
385 hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
386
387 /* warn the user (again) if there is no throughput data is available */
388 hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
389
390 if (batadv_is_wifi_hardif(hard_iface))
391 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
392
393 INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
394 batadv_v_elp_periodic_work);
395 batadv_v_elp_start_timer(hard_iface);
396 res = 0;
397
398 out:
399 return res;
400 }
401
402 /**
403 * batadv_v_elp_iface_disable() - release ELP interface private resources
404 * @hard_iface: interface for which the resources have to be released
405 */
406 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
407 {
408 cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
409
410 dev_kfree_skb(hard_iface->bat_v.elp_skb);
411 hard_iface->bat_v.elp_skb = NULL;
412 }
413
414 /**
415 * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
416 * hard-interface
417 * @primary_iface: the new primary interface
418 * @hard_iface: interface holding the to-be-updated buffer
419 */
420 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
421 struct batadv_hard_iface *hard_iface)
422 {
423 struct batadv_elp_packet *elp_packet;
424 struct sk_buff *skb;
425
426 if (!hard_iface->bat_v.elp_skb)
427 return;
428
429 skb = hard_iface->bat_v.elp_skb;
430 elp_packet = (struct batadv_elp_packet *)skb->data;
431 ether_addr_copy(elp_packet->orig,
432 primary_iface->net_dev->dev_addr);
433 }
434
435 /**
436 * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
437 * primary interface
438 * @primary_iface: the new primary interface
439 */
440 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
441 {
442 struct batadv_hard_iface *hard_iface;
443
444 /* update orig field of every elp iface belonging to this mesh */
445 rcu_read_lock();
446 list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
447 if (primary_iface->soft_iface != hard_iface->soft_iface)
448 continue;
449
450 batadv_v_elp_iface_activate(primary_iface, hard_iface);
451 }
452 rcu_read_unlock();
453 }
454
455 /**
456 * batadv_v_elp_neigh_update() - update an ELP neighbour node
457 * @bat_priv: the bat priv with all the soft interface information
458 * @neigh_addr: the neighbour interface address
459 * @if_incoming: the interface the packet was received through
460 * @elp_packet: the received ELP packet
461 *
462 * Updates the ELP neighbour node state with the data received within the new
463 * ELP packet.
464 */
465 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
466 u8 *neigh_addr,
467 struct batadv_hard_iface *if_incoming,
468 struct batadv_elp_packet *elp_packet)
469
470 {
471 struct batadv_neigh_node *neigh;
472 struct batadv_orig_node *orig_neigh;
473 struct batadv_hardif_neigh_node *hardif_neigh;
474 s32 seqno_diff;
475 s32 elp_latest_seqno;
476
477 orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
478 if (!orig_neigh)
479 return;
480
481 neigh = batadv_neigh_node_get_or_create(orig_neigh,
482 if_incoming, neigh_addr);
483 if (!neigh)
484 goto orig_free;
485
486 hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
487 if (!hardif_neigh)
488 goto neigh_free;
489
490 elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
491 seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
492
493 /* known or older sequence numbers are ignored. However always adopt
494 * if the router seems to have been restarted.
495 */
496 if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
497 goto hardif_free;
498
499 neigh->last_seen = jiffies;
500 hardif_neigh->last_seen = jiffies;
501 hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
502 hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
503
504 hardif_free:
505 if (hardif_neigh)
506 batadv_hardif_neigh_put(hardif_neigh);
507 neigh_free:
508 if (neigh)
509 batadv_neigh_node_put(neigh);
510 orig_free:
511 if (orig_neigh)
512 batadv_orig_node_put(orig_neigh);
513 }
514
515 /**
516 * batadv_v_elp_packet_recv() - main ELP packet handler
517 * @skb: the received packet
518 * @if_incoming: the interface this packet was received through
519 *
520 * Return: NET_RX_SUCCESS and consumes the skb if the packet was peoperly
521 * processed or NET_RX_DROP in case of failure.
522 */
523 int batadv_v_elp_packet_recv(struct sk_buff *skb,
524 struct batadv_hard_iface *if_incoming)
525 {
526 struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
527 struct batadv_elp_packet *elp_packet;
528 struct batadv_hard_iface *primary_if;
529 struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
530 bool res;
531 int ret = NET_RX_DROP;
532
533 res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
534 if (!res)
535 goto free_skb;
536
537 if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
538 goto free_skb;
539
540 /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
541 * that does not have B.A.T.M.A.N. V ELP enabled ?
542 */
543 if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
544 goto free_skb;
545
546 elp_packet = (struct batadv_elp_packet *)skb->data;
547
548 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
549 "Received ELP packet from %pM seqno %u ORIG: %pM\n",
550 ethhdr->h_source, ntohl(elp_packet->seqno),
551 elp_packet->orig);
552
553 primary_if = batadv_primary_if_get_selected(bat_priv);
554 if (!primary_if)
555 goto free_skb;
556
557 batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
558 elp_packet);
559
560 ret = NET_RX_SUCCESS;
561 batadv_hardif_put(primary_if);
562
563 free_skb:
564 if (ret == NET_RX_SUCCESS)
565 consume_skb(skb);
566 else
567 kfree_skb(skb);
568
569 return ret;
570 }
571
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