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