1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 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/container_of.h>
14 #include <linux/errno.h>
15 #include <linux/etherdevice.h>
16 #include <linux/ethtool.h>
17 #include <linux/gfp.h>
18 #include <linux/if_ether.h>
19 #include <linux/jiffies.h>
20 #include <linux/kref.h>
21 #include <linux/minmax.h>
22 #include <linux/netdevice.h>
23 #include <linux/nl80211.h>
24 #include <linux/random.h>
25 #include <linux/rculist.h>
26 #include <linux/rcupdate.h>
27 #include <linux/rtnetlink.h>
28 #include <linux/skbuff.h>
29 #include <linux/stddef.h>
30 #include <linux/string.h>
31 #include <linux/types.h>
32 #include <linux/workqueue.h>
33 #include <net/cfg80211.h>
34 #include <uapi/linux/batadv_packet.h>
35
36 #include "bat_algo.h"
37 #include "bat_v_ogm.h"
38 #include "hard-interface.h"
39 #include "log.h"
40 #include "originator.h"
41 #include "routing.h"
42 #include "send.h"
43
44 /**
45 * batadv_v_elp_start_timer() - restart timer for ELP periodic work
46 * @hard_iface: the interface for which the timer has to be reset
47 */
48 static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
49 {
50 unsigned int msecs;
51
52 msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
53 msecs += get_random_u32_below(2 * BATADV_JITTER);
54
55 queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
56 msecs_to_jiffies(msecs));
57 }
58
59 /**
60 * batadv_v_elp_get_throughput() - get the throughput towards a neighbour
61 * @neigh: the neighbour for which the throughput has to be obtained
62 *
63 * Return: The throughput towards the given neighbour in multiples of 100kpbs
64 * (a value of '1' equals 0.1Mbps, '10' equals 1Mbps, etc).
65 */
66 static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
67 {
68 struct batadv_hard_iface *hard_iface = neigh->if_incoming;
69 struct ethtool_link_ksettings link_settings;
70 struct net_device *real_netdev;
71 struct station_info sinfo;
72 u32 throughput;
73 int ret;
74
75 /* if the user specified a customised value for this interface, then
76 * return it directly
77 */
78 throughput = atomic_read(&hard_iface->bat_v.throughput_override);
79 if (throughput != 0)
80 return throughput;
81
82 /* if this is a wireless device, then ask its throughput through
83 * cfg80211 API
84 */
85 if (batadv_is_wifi_hardif(hard_iface)) {
86 if (!batadv_is_cfg80211_hardif(hard_iface))
87 /* unsupported WiFi driver version */
88 goto default_throughput;
89
90 real_netdev = batadv_get_real_netdev(hard_iface->net_dev);
91 if (!real_netdev)
92 goto default_throughput;
93
94 ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo);
95
96 if (!ret) {
97 /* free the TID stats immediately */
98 cfg80211_sinfo_release_content(&sinfo);
99 }
100
101 dev_put(real_netdev);
102 if (ret == -ENOENT) {
103 /* Node is not associated anymore! It would be
104 * possible to delete this neighbor. For now set
105 * the throughput metric to 0.
106 */
107 return 0;
108 }
109 if (ret)
110 goto default_throughput;
111
112 if (sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT))
113 return sinfo.expected_throughput / 100;
114
115 /* try to estimate the expected throughput based on reported tx
116 * rates
117 */
118 if (sinfo.filled & BIT(NL80211_STA_INFO_TX_BITRATE))
119 return cfg80211_calculate_bitrate(&sinfo.txrate) / 3;
120
121 goto default_throughput;
122 }
123
124 /* if not a wifi interface, check if this device provides data via
125 * ethtool (e.g. an Ethernet adapter)
126 */
127 rtnl_lock();
128 ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
129 rtnl_unlock();
130 if (ret == 0) {
131 /* link characteristics might change over time */
132 if (link_settings.base.duplex == DUPLEX_FULL)
133 hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
134 else
135 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
136
137 throughput = link_settings.base.speed;
138 if (throughput && throughput != SPEED_UNKNOWN)
139 return throughput * 10;
140 }
141
142 default_throughput:
143 if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
144 batadv_info(hard_iface->soft_iface,
145 "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",
146 hard_iface->net_dev->name,
147 BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
148 BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
149 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
150 }
151
152 /* if none of the above cases apply, return the base_throughput */
153 return BATADV_THROUGHPUT_DEFAULT_VALUE;
154 }
155
156 /**
157 * batadv_v_elp_throughput_metric_update() - worker updating the throughput
158 * metric of a single hop neighbour
159 * @work: the work queue item
160 */
161 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
162 {
163 struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
164 struct batadv_hardif_neigh_node *neigh;
165
166 neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
167 metric_work);
168 neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
169 bat_v);
170
171 ewma_throughput_add(&neigh->bat_v.throughput,
172 batadv_v_elp_get_throughput(neigh));
173
174 /* decrement refcounter to balance increment performed before scheduling
175 * this task
176 */
177 batadv_hardif_neigh_put(neigh);
178 }
179
180 /**
181 * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
182 * @neigh: the neighbour to probe
183 *
184 * Sends a predefined number of unicast wifi packets to a given neighbour in
185 * order to trigger the throughput estimation on this link by the RC algorithm.
186 * Packets are sent only if there is not enough payload unicast traffic towards
187 * this neighbour..
188 *
189 * Return: True on success and false in case of error during skb preparation.
190 */
191 static bool
192 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
193 {
194 struct batadv_hard_iface *hard_iface = neigh->if_incoming;
195 struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
196 unsigned long last_tx_diff;
197 struct sk_buff *skb;
198 int probe_len, i;
199 int elp_skb_len;
200
201 /* this probing routine is for Wifi neighbours only */
202 if (!batadv_is_wifi_hardif(hard_iface))
203 return true;
204
205 /* probe the neighbor only if no unicast packets have been sent
206 * to it in the last 100 milliseconds: this is the rate control
207 * algorithm sampling interval (minstrel). In this way, if not
208 * enough traffic has been sent to the neighbor, batman-adv can
209 * generate 2 probe packets and push the RC algorithm to perform
210 * the sampling
211 */
212 last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
213 if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
214 return true;
215
216 probe_len = max_t(int, sizeof(struct batadv_elp_packet),
217 BATADV_ELP_MIN_PROBE_SIZE);
218
219 for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
220 elp_skb_len = hard_iface->bat_v.elp_skb->len;
221 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
222 probe_len - elp_skb_len,
223 GFP_ATOMIC);
224 if (!skb)
225 return false;
226
227 /* Tell the skb to get as big as the allocated space (we want
228 * the packet to be exactly of that size to make the link
229 * throughput estimation effective.
230 */
231 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);
232
233 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
234 "Sending unicast (probe) ELP packet on interface %s to %pM\n",
235 hard_iface->net_dev->name, neigh->addr);
236
237 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
238 }
239
240 return true;
241 }
242
243 /**
244 * batadv_v_elp_periodic_work() - ELP periodic task per interface
245 * @work: work queue item
246 *
247 * Emits broadcast ELP messages in regular intervals.
248 */
249 static void batadv_v_elp_periodic_work(struct work_struct *work)
250 {
251 struct batadv_hardif_neigh_node *hardif_neigh;
252 struct batadv_hard_iface *hard_iface;
253 struct batadv_hard_iface_bat_v *bat_v;
254 struct batadv_elp_packet *elp_packet;
255 struct batadv_priv *bat_priv;
256 struct sk_buff *skb;
257 u32 elp_interval;
258 bool ret;
259
260 bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
261 hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
262 bat_priv = netdev_priv(hard_iface->soft_iface);
263
264 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
265 goto out;
266
267 /* we are in the process of shutting this interface down */
268 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
269 hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
270 goto out;
271
272 /* the interface was enabled but may not be ready yet */
273 if (hard_iface->if_status != BATADV_IF_ACTIVE)
274 goto restart_timer;
275
276 skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
277 if (!skb)
278 goto restart_timer;
279
280 elp_packet = (struct batadv_elp_packet *)skb->data;
281 elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
282 elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
283 elp_packet->elp_interval = htonl(elp_interval);
284
285 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
286 "Sending broadcast ELP packet on interface %s, seqno %u\n",
287 hard_iface->net_dev->name,
288 atomic_read(&hard_iface->bat_v.elp_seqno));
289
290 batadv_send_broadcast_skb(skb, hard_iface);
291
292 atomic_inc(&hard_iface->bat_v.elp_seqno);
293
294 /* The throughput metric is updated on each sent packet. This way, if a
295 * node is dead and no longer sends packets, batman-adv is still able to
296 * react timely to its death.
297 *
298 * The throughput metric is updated by following these steps:
299 * 1) if the hard_iface is wifi => send a number of unicast ELPs for
300 * probing/sampling to each neighbor
301 * 2) update the throughput metric value of each neighbor (note that the
302 * value retrieved in this step might be 100ms old because the
303 * probing packets at point 1) could still be in the HW queue)
304 */
305 rcu_read_lock();
306 hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
307 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
308 /* if something goes wrong while probing, better to stop
309 * sending packets immediately and reschedule the task
310 */
311 break;
312
313 if (!kref_get_unless_zero(&hardif_neigh->refcount))
314 continue;
315
316 /* Reading the estimated throughput from cfg80211 is a task that
317 * may sleep and that is not allowed in an rcu protected
318 * context. Therefore schedule a task for that.
319 */
320 ret = queue_work(batadv_event_workqueue,
321 &hardif_neigh->bat_v.metric_work);
322
323 if (!ret)
324 batadv_hardif_neigh_put(hardif_neigh);
325 }
326 rcu_read_unlock();
327
328 restart_timer:
329 batadv_v_elp_start_timer(hard_iface);
330 out:
331 return;
332 }
333
334 /**
335 * batadv_v_elp_iface_enable() - setup the ELP interface private resources
336 * @hard_iface: interface for which the data has to be prepared
337 *
338 * Return: 0 on success or a -ENOMEM in case of failure.
339 */
340 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
341 {
342 static const size_t tvlv_padding = sizeof(__be32);
343 struct batadv_elp_packet *elp_packet;
344 unsigned char *elp_buff;
345 u32 random_seqno;
346 size_t size;
347 int res = -ENOMEM;
348
349 size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
350 hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
351 if (!hard_iface->bat_v.elp_skb)
352 goto out;
353
354 skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
355 elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
356 BATADV_ELP_HLEN + tvlv_padding);
357 elp_packet = (struct batadv_elp_packet *)elp_buff;
358
359 elp_packet->packet_type = BATADV_ELP;
360 elp_packet->version = BATADV_COMPAT_VERSION;
361
362 /* randomize initial seqno to avoid collision */
363 get_random_bytes(&random_seqno, sizeof(random_seqno));
364 atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
365
366 /* assume full-duplex by default */
367 hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
368
369 /* warn the user (again) if there is no throughput data is available */
370 hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
371
372 if (batadv_is_wifi_hardif(hard_iface))
373 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
374
375 INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
376 batadv_v_elp_periodic_work);
377 batadv_v_elp_start_timer(hard_iface);
378 res = 0;
379
380 out:
381 return res;
382 }
383
384 /**
385 * batadv_v_elp_iface_disable() - release ELP interface private resources
386 * @hard_iface: interface for which the resources have to be released
387 */
388 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
389 {
390 cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
391
392 dev_kfree_skb(hard_iface->bat_v.elp_skb);
393 hard_iface->bat_v.elp_skb = NULL;
394 }
395
396 /**
397 * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
398 * hard-interface
399 * @primary_iface: the new primary interface
400 * @hard_iface: interface holding the to-be-updated buffer
401 */
402 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
403 struct batadv_hard_iface *hard_iface)
404 {
405 struct batadv_elp_packet *elp_packet;
406 struct sk_buff *skb;
407
408 if (!hard_iface->bat_v.elp_skb)
409 return;
410
411 skb = hard_iface->bat_v.elp_skb;
412 elp_packet = (struct batadv_elp_packet *)skb->data;
413 ether_addr_copy(elp_packet->orig,
414 primary_iface->net_dev->dev_addr);
415 }
416
417 /**
418 * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
419 * primary interface
420 * @primary_iface: the new primary interface
421 */
422 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
423 {
424 struct batadv_hard_iface *hard_iface;
425
426 /* update orig field of every elp iface belonging to this mesh */
427 rcu_read_lock();
428 list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
429 if (primary_iface->soft_iface != hard_iface->soft_iface)
430 continue;
431
432 batadv_v_elp_iface_activate(primary_iface, hard_iface);
433 }
434 rcu_read_unlock();
435 }
436
437 /**
438 * batadv_v_elp_neigh_update() - update an ELP neighbour node
439 * @bat_priv: the bat priv with all the soft interface information
440 * @neigh_addr: the neighbour interface address
441 * @if_incoming: the interface the packet was received through
442 * @elp_packet: the received ELP packet
443 *
444 * Updates the ELP neighbour node state with the data received within the new
445 * ELP packet.
446 */
447 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
448 u8 *neigh_addr,
449 struct batadv_hard_iface *if_incoming,
450 struct batadv_elp_packet *elp_packet)
451
452 {
453 struct batadv_neigh_node *neigh;
454 struct batadv_orig_node *orig_neigh;
455 struct batadv_hardif_neigh_node *hardif_neigh;
456 s32 seqno_diff;
457 s32 elp_latest_seqno;
458
459 orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
460 if (!orig_neigh)
461 return;
462
463 neigh = batadv_neigh_node_get_or_create(orig_neigh,
464 if_incoming, neigh_addr);
465 if (!neigh)
466 goto orig_free;
467
468 hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
469 if (!hardif_neigh)
470 goto neigh_free;
471
472 elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
473 seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
474
475 /* known or older sequence numbers are ignored. However always adopt
476 * if the router seems to have been restarted.
477 */
478 if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
479 goto hardif_free;
480
481 neigh->last_seen = jiffies;
482 hardif_neigh->last_seen = jiffies;
483 hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
484 hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
485
486 hardif_free:
487 batadv_hardif_neigh_put(hardif_neigh);
488 neigh_free:
489 batadv_neigh_node_put(neigh);
490 orig_free:
491 batadv_orig_node_put(orig_neigh);
492 }
493
494 /**
495 * batadv_v_elp_packet_recv() - main ELP packet handler
496 * @skb: the received packet
497 * @if_incoming: the interface this packet was received through
498 *
499 * Return: NET_RX_SUCCESS and consumes the skb if the packet was properly
500 * processed or NET_RX_DROP in case of failure.
501 */
502 int batadv_v_elp_packet_recv(struct sk_buff *skb,
503 struct batadv_hard_iface *if_incoming)
504 {
505 struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
506 struct batadv_elp_packet *elp_packet;
507 struct batadv_hard_iface *primary_if;
508 struct ethhdr *ethhdr;
509 bool res;
510 int ret = NET_RX_DROP;
511
512 res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
513 if (!res)
514 goto free_skb;
515
516 ethhdr = eth_hdr(skb);
517 if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
518 goto free_skb;
519
520 /* did we receive a B.A.T.M.A.N. V ELP packet on an interface
521 * that does not have B.A.T.M.A.N. V ELP enabled ?
522 */
523 if (strcmp(bat_priv->algo_ops->name, "BATMAN_V") != 0)
524 goto free_skb;
525
526 elp_packet = (struct batadv_elp_packet *)skb->data;
527
528 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
529 "Received ELP packet from %pM seqno %u ORIG: %pM\n",
530 ethhdr->h_source, ntohl(elp_packet->seqno),
531 elp_packet->orig);
532
533 primary_if = batadv_primary_if_get_selected(bat_priv);
534 if (!primary_if)
535 goto free_skb;
536
537 batadv_v_elp_neigh_update(bat_priv, ethhdr->h_source, if_incoming,
538 elp_packet);
539
540 ret = NET_RX_SUCCESS;
541 batadv_hardif_put(primary_if);
542
543 free_skb:
544 if (ret == NET_RX_SUCCESS)
545 consume_skb(skb);
546 else
547 kfree_skb(skb);
548
549 return ret;
550 }
551
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