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/prandom.h>
25 #include <linux/random.h>
26 #include <linux/rculist.h>
27 #include <linux/rcupdate.h>
28 #include <linux/rtnetlink.h>
29 #include <linux/skbuff.h>
30 #include <linux/stddef.h>
31 #include <linux/string.h>
32 #include <linux/types.h>
33 #include <linux/workqueue.h>
34 #include <net/cfg80211.h>
35 #include <uapi/linux/batadv_packet.h>
36
37 #include "bat_algo.h"
38 #include "bat_v_ogm.h"
39 #include "hard-interface.h"
40 #include "log.h"
41 #include "originator.h"
42 #include "routing.h"
43 #include "send.h"
44
45 /**
46 * batadv_v_elp_start_timer() - restart timer for ELP periodic work
47 * @hard_iface: the interface for which the timer has to be reset
48 */
batadv_v_elp_start_timer(struct batadv_hard_iface * hard_iface)49 static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
50 {
51 unsigned int msecs;
52
53 msecs = atomic_read(&hard_iface->bat_v.elp_interval) - BATADV_JITTER;
54 msecs += prandom_u32_max(2 * BATADV_JITTER);
55
56 queue_delayed_work(batadv_event_workqueue, &hard_iface->bat_v.elp_wq,
57 msecs_to_jiffies(msecs));
58 }
59
60 /**
61 * batadv_v_elp_get_throughput() - get the throughput towards a neighbour
62 * @neigh: the neighbour for which the throughput has to be obtained
63 *
64 * Return: The throughput towards the given neighbour in multiples of 100kpbs
65 * (a value of '1' equals 0.1Mbps, '10' equals 1Mbps, etc).
66 */
batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node * neigh)67 static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
68 {
69 struct batadv_hard_iface *hard_iface = neigh->if_incoming;
70 struct ethtool_link_ksettings link_settings;
71 struct net_device *real_netdev;
72 struct station_info sinfo;
73 u32 throughput;
74 int ret;
75
76 /* if the user specified a customised value for this interface, then
77 * return it directly
78 */
79 throughput = atomic_read(&hard_iface->bat_v.throughput_override);
80 if (throughput != 0)
81 return throughput;
82
83 /* if this is a wireless device, then ask its throughput through
84 * cfg80211 API
85 */
86 if (batadv_is_wifi_hardif(hard_iface)) {
87 if (!batadv_is_cfg80211_hardif(hard_iface))
88 /* unsupported WiFi driver version */
89 goto default_throughput;
90
91 real_netdev = batadv_get_real_netdev(hard_iface->net_dev);
92 if (!real_netdev)
93 goto default_throughput;
94
95 ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo);
96
97 if (!ret) {
98 /* free the TID stats immediately */
99 cfg80211_sinfo_release_content(&sinfo);
100 }
101
102 dev_put(real_netdev);
103 if (ret == -ENOENT) {
104 /* Node is not associated anymore! It would be
105 * possible to delete this neighbor. For now set
106 * the throughput metric to 0.
107 */
108 return 0;
109 }
110 if (ret)
111 goto default_throughput;
112
113 if (sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT))
114 return sinfo.expected_throughput / 100;
115
116 /* try to estimate the expected throughput based on reported tx
117 * rates
118 */
119 if (sinfo.filled & BIT(NL80211_STA_INFO_TX_BITRATE))
120 return cfg80211_calculate_bitrate(&sinfo.txrate) / 3;
121
122 goto default_throughput;
123 }
124
125 /* if not a wifi interface, check if this device provides data via
126 * ethtool (e.g. an Ethernet adapter)
127 */
128 rtnl_lock();
129 ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings);
130 rtnl_unlock();
131 if (ret == 0) {
132 /* link characteristics might change over time */
133 if (link_settings.base.duplex == DUPLEX_FULL)
134 hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
135 else
136 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
137
138 throughput = link_settings.base.speed;
139 if (throughput && throughput != SPEED_UNKNOWN)
140 return throughput * 10;
141 }
142
143 default_throughput:
144 if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
145 batadv_info(hard_iface->soft_iface,
146 "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",
147 hard_iface->net_dev->name,
148 BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
149 BATADV_THROUGHPUT_DEFAULT_VALUE % 10);
150 hard_iface->bat_v.flags |= BATADV_WARNING_DEFAULT;
151 }
152
153 /* if none of the above cases apply, return the base_throughput */
154 return BATADV_THROUGHPUT_DEFAULT_VALUE;
155 }
156
157 /**
158 * batadv_v_elp_throughput_metric_update() - worker updating the throughput
159 * metric of a single hop neighbour
160 * @work: the work queue item
161 */
batadv_v_elp_throughput_metric_update(struct work_struct * work)162 void batadv_v_elp_throughput_metric_update(struct work_struct *work)
163 {
164 struct batadv_hardif_neigh_node_bat_v *neigh_bat_v;
165 struct batadv_hardif_neigh_node *neigh;
166
167 neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v,
168 metric_work);
169 neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node,
170 bat_v);
171
172 ewma_throughput_add(&neigh->bat_v.throughput,
173 batadv_v_elp_get_throughput(neigh));
174
175 /* decrement refcounter to balance increment performed before scheduling
176 * this task
177 */
178 batadv_hardif_neigh_put(neigh);
179 }
180
181 /**
182 * batadv_v_elp_wifi_neigh_probe() - send link probing packets to a neighbour
183 * @neigh: the neighbour to probe
184 *
185 * Sends a predefined number of unicast wifi packets to a given neighbour in
186 * order to trigger the throughput estimation on this link by the RC algorithm.
187 * Packets are sent only if there is not enough payload unicast traffic towards
188 * this neighbour..
189 *
190 * Return: True on success and false in case of error during skb preparation.
191 */
192 static bool
batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node * neigh)193 batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh)
194 {
195 struct batadv_hard_iface *hard_iface = neigh->if_incoming;
196 struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
197 unsigned long last_tx_diff;
198 struct sk_buff *skb;
199 int probe_len, i;
200 int elp_skb_len;
201
202 /* this probing routine is for Wifi neighbours only */
203 if (!batadv_is_wifi_hardif(hard_iface))
204 return true;
205
206 /* probe the neighbor only if no unicast packets have been sent
207 * to it in the last 100 milliseconds: this is the rate control
208 * algorithm sampling interval (minstrel). In this way, if not
209 * enough traffic has been sent to the neighbor, batman-adv can
210 * generate 2 probe packets and push the RC algorithm to perform
211 * the sampling
212 */
213 last_tx_diff = jiffies_to_msecs(jiffies - neigh->bat_v.last_unicast_tx);
214 if (last_tx_diff <= BATADV_ELP_PROBE_MAX_TX_DIFF)
215 return true;
216
217 probe_len = max_t(int, sizeof(struct batadv_elp_packet),
218 BATADV_ELP_MIN_PROBE_SIZE);
219
220 for (i = 0; i < BATADV_ELP_PROBES_PER_NODE; i++) {
221 elp_skb_len = hard_iface->bat_v.elp_skb->len;
222 skb = skb_copy_expand(hard_iface->bat_v.elp_skb, 0,
223 probe_len - elp_skb_len,
224 GFP_ATOMIC);
225 if (!skb)
226 return false;
227
228 /* Tell the skb to get as big as the allocated space (we want
229 * the packet to be exactly of that size to make the link
230 * throughput estimation effective.
231 */
232 skb_put_zero(skb, probe_len - hard_iface->bat_v.elp_skb->len);
233
234 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
235 "Sending unicast (probe) ELP packet on interface %s to %pM\n",
236 hard_iface->net_dev->name, neigh->addr);
237
238 batadv_send_skb_packet(skb, hard_iface, neigh->addr);
239 }
240
241 return true;
242 }
243
244 /**
245 * batadv_v_elp_periodic_work() - ELP periodic task per interface
246 * @work: work queue item
247 *
248 * Emits broadcast ELP messages in regular intervals.
249 */
batadv_v_elp_periodic_work(struct work_struct * work)250 static void batadv_v_elp_periodic_work(struct work_struct *work)
251 {
252 struct batadv_hardif_neigh_node *hardif_neigh;
253 struct batadv_hard_iface *hard_iface;
254 struct batadv_hard_iface_bat_v *bat_v;
255 struct batadv_elp_packet *elp_packet;
256 struct batadv_priv *bat_priv;
257 struct sk_buff *skb;
258 u32 elp_interval;
259 bool ret;
260
261 bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work);
262 hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v);
263 bat_priv = netdev_priv(hard_iface->soft_iface);
264
265 if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
266 goto out;
267
268 /* we are in the process of shutting this interface down */
269 if (hard_iface->if_status == BATADV_IF_NOT_IN_USE ||
270 hard_iface->if_status == BATADV_IF_TO_BE_REMOVED)
271 goto out;
272
273 /* the interface was enabled but may not be ready yet */
274 if (hard_iface->if_status != BATADV_IF_ACTIVE)
275 goto restart_timer;
276
277 skb = skb_copy(hard_iface->bat_v.elp_skb, GFP_ATOMIC);
278 if (!skb)
279 goto restart_timer;
280
281 elp_packet = (struct batadv_elp_packet *)skb->data;
282 elp_packet->seqno = htonl(atomic_read(&hard_iface->bat_v.elp_seqno));
283 elp_interval = atomic_read(&hard_iface->bat_v.elp_interval);
284 elp_packet->elp_interval = htonl(elp_interval);
285
286 batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
287 "Sending broadcast ELP packet on interface %s, seqno %u\n",
288 hard_iface->net_dev->name,
289 atomic_read(&hard_iface->bat_v.elp_seqno));
290
291 batadv_send_broadcast_skb(skb, hard_iface);
292
293 atomic_inc(&hard_iface->bat_v.elp_seqno);
294
295 /* The throughput metric is updated on each sent packet. This way, if a
296 * node is dead and no longer sends packets, batman-adv is still able to
297 * react timely to its death.
298 *
299 * The throughput metric is updated by following these steps:
300 * 1) if the hard_iface is wifi => send a number of unicast ELPs for
301 * probing/sampling to each neighbor
302 * 2) update the throughput metric value of each neighbor (note that the
303 * value retrieved in this step might be 100ms old because the
304 * probing packets at point 1) could still be in the HW queue)
305 */
306 rcu_read_lock();
307 hlist_for_each_entry_rcu(hardif_neigh, &hard_iface->neigh_list, list) {
308 if (!batadv_v_elp_wifi_neigh_probe(hardif_neigh))
309 /* if something goes wrong while probing, better to stop
310 * sending packets immediately and reschedule the task
311 */
312 break;
313
314 if (!kref_get_unless_zero(&hardif_neigh->refcount))
315 continue;
316
317 /* Reading the estimated throughput from cfg80211 is a task that
318 * may sleep and that is not allowed in an rcu protected
319 * context. Therefore schedule a task for that.
320 */
321 ret = queue_work(batadv_event_workqueue,
322 &hardif_neigh->bat_v.metric_work);
323
324 if (!ret)
325 batadv_hardif_neigh_put(hardif_neigh);
326 }
327 rcu_read_unlock();
328
329 restart_timer:
330 batadv_v_elp_start_timer(hard_iface);
331 out:
332 return;
333 }
334
335 /**
336 * batadv_v_elp_iface_enable() - setup the ELP interface private resources
337 * @hard_iface: interface for which the data has to be prepared
338 *
339 * Return: 0 on success or a -ENOMEM in case of failure.
340 */
batadv_v_elp_iface_enable(struct batadv_hard_iface * hard_iface)341 int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface)
342 {
343 static const size_t tvlv_padding = sizeof(__be32);
344 struct batadv_elp_packet *elp_packet;
345 unsigned char *elp_buff;
346 u32 random_seqno;
347 size_t size;
348 int res = -ENOMEM;
349
350 size = ETH_HLEN + NET_IP_ALIGN + BATADV_ELP_HLEN + tvlv_padding;
351 hard_iface->bat_v.elp_skb = dev_alloc_skb(size);
352 if (!hard_iface->bat_v.elp_skb)
353 goto out;
354
355 skb_reserve(hard_iface->bat_v.elp_skb, ETH_HLEN + NET_IP_ALIGN);
356 elp_buff = skb_put_zero(hard_iface->bat_v.elp_skb,
357 BATADV_ELP_HLEN + tvlv_padding);
358 elp_packet = (struct batadv_elp_packet *)elp_buff;
359
360 elp_packet->packet_type = BATADV_ELP;
361 elp_packet->version = BATADV_COMPAT_VERSION;
362
363 /* randomize initial seqno to avoid collision */
364 get_random_bytes(&random_seqno, sizeof(random_seqno));
365 atomic_set(&hard_iface->bat_v.elp_seqno, random_seqno);
366
367 /* assume full-duplex by default */
368 hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;
369
370 /* warn the user (again) if there is no throughput data is available */
371 hard_iface->bat_v.flags &= ~BATADV_WARNING_DEFAULT;
372
373 if (batadv_is_wifi_hardif(hard_iface))
374 hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
375
376 INIT_DELAYED_WORK(&hard_iface->bat_v.elp_wq,
377 batadv_v_elp_periodic_work);
378 batadv_v_elp_start_timer(hard_iface);
379 res = 0;
380
381 out:
382 return res;
383 }
384
385 /**
386 * batadv_v_elp_iface_disable() - release ELP interface private resources
387 * @hard_iface: interface for which the resources have to be released
388 */
batadv_v_elp_iface_disable(struct batadv_hard_iface * hard_iface)389 void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface)
390 {
391 cancel_delayed_work_sync(&hard_iface->bat_v.elp_wq);
392
393 dev_kfree_skb(hard_iface->bat_v.elp_skb);
394 hard_iface->bat_v.elp_skb = NULL;
395 }
396
397 /**
398 * batadv_v_elp_iface_activate() - update the ELP buffer belonging to the given
399 * hard-interface
400 * @primary_iface: the new primary interface
401 * @hard_iface: interface holding the to-be-updated buffer
402 */
batadv_v_elp_iface_activate(struct batadv_hard_iface * primary_iface,struct batadv_hard_iface * hard_iface)403 void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface,
404 struct batadv_hard_iface *hard_iface)
405 {
406 struct batadv_elp_packet *elp_packet;
407 struct sk_buff *skb;
408
409 if (!hard_iface->bat_v.elp_skb)
410 return;
411
412 skb = hard_iface->bat_v.elp_skb;
413 elp_packet = (struct batadv_elp_packet *)skb->data;
414 ether_addr_copy(elp_packet->orig,
415 primary_iface->net_dev->dev_addr);
416 }
417
418 /**
419 * batadv_v_elp_primary_iface_set() - change internal data to reflect the new
420 * primary interface
421 * @primary_iface: the new primary interface
422 */
batadv_v_elp_primary_iface_set(struct batadv_hard_iface * primary_iface)423 void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface)
424 {
425 struct batadv_hard_iface *hard_iface;
426
427 /* update orig field of every elp iface belonging to this mesh */
428 rcu_read_lock();
429 list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
430 if (primary_iface->soft_iface != hard_iface->soft_iface)
431 continue;
432
433 batadv_v_elp_iface_activate(primary_iface, hard_iface);
434 }
435 rcu_read_unlock();
436 }
437
438 /**
439 * batadv_v_elp_neigh_update() - update an ELP neighbour node
440 * @bat_priv: the bat priv with all the soft interface information
441 * @neigh_addr: the neighbour interface address
442 * @if_incoming: the interface the packet was received through
443 * @elp_packet: the received ELP packet
444 *
445 * Updates the ELP neighbour node state with the data received within the new
446 * ELP packet.
447 */
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)448 static void batadv_v_elp_neigh_update(struct batadv_priv *bat_priv,
449 u8 *neigh_addr,
450 struct batadv_hard_iface *if_incoming,
451 struct batadv_elp_packet *elp_packet)
452
453 {
454 struct batadv_neigh_node *neigh;
455 struct batadv_orig_node *orig_neigh;
456 struct batadv_hardif_neigh_node *hardif_neigh;
457 s32 seqno_diff;
458 s32 elp_latest_seqno;
459
460 orig_neigh = batadv_v_ogm_orig_get(bat_priv, elp_packet->orig);
461 if (!orig_neigh)
462 return;
463
464 neigh = batadv_neigh_node_get_or_create(orig_neigh,
465 if_incoming, neigh_addr);
466 if (!neigh)
467 goto orig_free;
468
469 hardif_neigh = batadv_hardif_neigh_get(if_incoming, neigh_addr);
470 if (!hardif_neigh)
471 goto neigh_free;
472
473 elp_latest_seqno = hardif_neigh->bat_v.elp_latest_seqno;
474 seqno_diff = ntohl(elp_packet->seqno) - elp_latest_seqno;
475
476 /* known or older sequence numbers are ignored. However always adopt
477 * if the router seems to have been restarted.
478 */
479 if (seqno_diff < 1 && seqno_diff > -BATADV_ELP_MAX_AGE)
480 goto hardif_free;
481
482 neigh->last_seen = jiffies;
483 hardif_neigh->last_seen = jiffies;
484 hardif_neigh->bat_v.elp_latest_seqno = ntohl(elp_packet->seqno);
485 hardif_neigh->bat_v.elp_interval = ntohl(elp_packet->elp_interval);
486
487 hardif_free:
488 batadv_hardif_neigh_put(hardif_neigh);
489 neigh_free:
490 batadv_neigh_node_put(neigh);
491 orig_free:
492 batadv_orig_node_put(orig_neigh);
493 }
494
495 /**
496 * batadv_v_elp_packet_recv() - main ELP packet handler
497 * @skb: the received packet
498 * @if_incoming: the interface this packet was received through
499 *
500 * Return: NET_RX_SUCCESS and consumes the skb if the packet was properly
501 * processed or NET_RX_DROP in case of failure.
502 */
batadv_v_elp_packet_recv(struct sk_buff * skb,struct batadv_hard_iface * if_incoming)503 int batadv_v_elp_packet_recv(struct sk_buff *skb,
504 struct batadv_hard_iface *if_incoming)
505 {
506 struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
507 struct batadv_elp_packet *elp_packet;
508 struct batadv_hard_iface *primary_if;
509 struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
510 bool res;
511 int ret = NET_RX_DROP;
512
513 res = batadv_check_management_packet(skb, if_incoming, BATADV_ELP_HLEN);
514 if (!res)
515 goto free_skb;
516
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