xref: /linux/net/mac802154/scan.c (revision fdd51b3e73e906aac056f2c337710185607d43d1)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * IEEE 802.15.4 scanning management
4  *
5  * Copyright (C) 2021 Qorvo US, Inc
6  * Authors:
7  *   - David Girault <david.girault@qorvo.com>
8  *   - Miquel Raynal <miquel.raynal@bootlin.com>
9  */
10 
11 #include <linux/module.h>
12 #include <linux/rtnetlink.h>
13 #include <net/mac802154.h>
14 
15 #include "ieee802154_i.h"
16 #include "driver-ops.h"
17 #include "../ieee802154/nl802154.h"
18 
19 #define IEEE802154_BEACON_MHR_SZ 13
20 #define IEEE802154_BEACON_PL_SZ 4
21 #define IEEE802154_MAC_CMD_MHR_SZ 23
22 #define IEEE802154_MAC_CMD_PL_SZ 1
23 #define IEEE802154_BEACON_SKB_SZ (IEEE802154_BEACON_MHR_SZ + \
24 				  IEEE802154_BEACON_PL_SZ)
25 #define IEEE802154_MAC_CMD_SKB_SZ (IEEE802154_MAC_CMD_MHR_SZ + \
26 				   IEEE802154_MAC_CMD_PL_SZ)
27 
28 /* mac802154_scan_cleanup_locked() must be called upon scan completion or abort.
29  * - Completions are asynchronous, not locked by the rtnl and decided by the
30  *   scan worker.
31  * - Aborts are decided by userspace, and locked by the rtnl.
32  *
33  * Concurrent modifications to the PHY, the interfaces or the hardware is in
34  * general prevented by the rtnl. So in most cases we don't need additional
35  * protection.
36  *
37  * However, the scan worker get's triggered without anybody noticing and thus we
38  * must ensure the presence of the devices as well as data consistency:
39  * - The sub-interface and device driver module get both their reference
40  *   counters incremented whenever we start a scan, so they cannot disappear
41  *   during operation.
42  * - Data consistency is achieved by the use of rcu protected pointers.
43  */
44 static int mac802154_scan_cleanup_locked(struct ieee802154_local *local,
45 					 struct ieee802154_sub_if_data *sdata,
46 					 bool aborted)
47 {
48 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
49 	struct wpan_phy *wpan_phy = local->phy;
50 	struct cfg802154_scan_request *request;
51 	u8 arg;
52 
53 	/* Prevent any further use of the scan request */
54 	clear_bit(IEEE802154_IS_SCANNING, &local->ongoing);
55 	cancel_delayed_work(&local->scan_work);
56 	request = rcu_replace_pointer(local->scan_req, NULL, 1);
57 	if (!request)
58 		return 0;
59 	kvfree_rcu_mightsleep(request);
60 
61 	/* Advertize first, while we know the devices cannot be removed */
62 	if (aborted)
63 		arg = NL802154_SCAN_DONE_REASON_ABORTED;
64 	else
65 		arg = NL802154_SCAN_DONE_REASON_FINISHED;
66 	nl802154_scan_done(wpan_phy, wpan_dev, arg);
67 
68 	/* Cleanup software stack */
69 	ieee802154_mlme_op_post(local);
70 
71 	/* Set the hardware back in its original state */
72 	drv_set_channel(local, wpan_phy->current_page,
73 			wpan_phy->current_channel);
74 	ieee802154_configure_durations(wpan_phy, wpan_phy->current_page,
75 				       wpan_phy->current_channel);
76 	drv_stop(local);
77 	synchronize_net();
78 	sdata->required_filtering = sdata->iface_default_filtering;
79 	drv_start(local, sdata->required_filtering, &local->addr_filt);
80 
81 	return 0;
82 }
83 
84 int mac802154_abort_scan_locked(struct ieee802154_local *local,
85 				struct ieee802154_sub_if_data *sdata)
86 {
87 	ASSERT_RTNL();
88 
89 	if (!mac802154_is_scanning(local))
90 		return -ESRCH;
91 
92 	return mac802154_scan_cleanup_locked(local, sdata, true);
93 }
94 
95 static unsigned int mac802154_scan_get_channel_time(u8 duration_order,
96 						    u8 symbol_duration)
97 {
98 	u64 base_super_frame_duration = (u64)symbol_duration *
99 		IEEE802154_SUPERFRAME_PERIOD * IEEE802154_SLOT_PERIOD;
100 
101 	return usecs_to_jiffies(base_super_frame_duration *
102 				(BIT(duration_order) + 1));
103 }
104 
105 static void mac802154_flush_queued_beacons(struct ieee802154_local *local)
106 {
107 	struct cfg802154_mac_pkt *mac_pkt, *tmp;
108 
109 	list_for_each_entry_safe(mac_pkt, tmp, &local->rx_beacon_list, node) {
110 		list_del(&mac_pkt->node);
111 		kfree_skb(mac_pkt->skb);
112 		kfree(mac_pkt);
113 	}
114 }
115 
116 static void
117 mac802154_scan_get_next_channel(struct ieee802154_local *local,
118 				struct cfg802154_scan_request *scan_req,
119 				u8 *channel)
120 {
121 	(*channel)++;
122 	*channel = find_next_bit((const unsigned long *)&scan_req->channels,
123 				 IEEE802154_MAX_CHANNEL + 1,
124 				 *channel);
125 }
126 
127 static int mac802154_scan_find_next_chan(struct ieee802154_local *local,
128 					 struct cfg802154_scan_request *scan_req,
129 					 u8 page, u8 *channel)
130 {
131 	mac802154_scan_get_next_channel(local, scan_req, channel);
132 	if (*channel > IEEE802154_MAX_CHANNEL)
133 		return -EINVAL;
134 
135 	return 0;
136 }
137 
138 static int mac802154_scan_prepare_beacon_req(struct ieee802154_local *local)
139 {
140 	memset(&local->scan_beacon_req, 0, sizeof(local->scan_beacon_req));
141 	local->scan_beacon_req.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
142 	local->scan_beacon_req.mhr.fc.dest_addr_mode = IEEE802154_SHORT_ADDRESSING;
143 	local->scan_beacon_req.mhr.fc.version = IEEE802154_2003_STD;
144 	local->scan_beacon_req.mhr.fc.source_addr_mode = IEEE802154_NO_ADDRESSING;
145 	local->scan_beacon_req.mhr.dest.mode = IEEE802154_ADDR_SHORT;
146 	local->scan_beacon_req.mhr.dest.pan_id = cpu_to_le16(IEEE802154_PANID_BROADCAST);
147 	local->scan_beacon_req.mhr.dest.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
148 	local->scan_beacon_req.mac_pl.cmd_id = IEEE802154_CMD_BEACON_REQ;
149 
150 	return 0;
151 }
152 
153 static int mac802154_transmit_beacon_req(struct ieee802154_local *local,
154 					 struct ieee802154_sub_if_data *sdata)
155 {
156 	struct sk_buff *skb;
157 	int ret;
158 
159 	skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ, GFP_KERNEL);
160 	if (!skb)
161 		return -ENOBUFS;
162 
163 	skb->dev = sdata->dev;
164 
165 	ret = ieee802154_mac_cmd_push(skb, &local->scan_beacon_req, NULL, 0);
166 	if (ret) {
167 		kfree_skb(skb);
168 		return ret;
169 	}
170 
171 	return ieee802154_mlme_tx(local, sdata, skb);
172 }
173 
174 void mac802154_scan_worker(struct work_struct *work)
175 {
176 	struct ieee802154_local *local =
177 		container_of(work, struct ieee802154_local, scan_work.work);
178 	struct cfg802154_scan_request *scan_req;
179 	struct ieee802154_sub_if_data *sdata;
180 	unsigned int scan_duration = 0;
181 	struct wpan_phy *wpan_phy;
182 	u8 scan_req_duration;
183 	u8 page, channel;
184 	int ret;
185 
186 	/* Ensure the device receiver is turned off when changing channels
187 	 * because there is no atomic way to change the channel and know on
188 	 * which one a beacon might have been received.
189 	 */
190 	drv_stop(local);
191 	synchronize_net();
192 	mac802154_flush_queued_beacons(local);
193 
194 	rcu_read_lock();
195 	scan_req = rcu_dereference(local->scan_req);
196 	if (unlikely(!scan_req)) {
197 		rcu_read_unlock();
198 		return;
199 	}
200 
201 	sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(scan_req->wpan_dev);
202 
203 	/* Wait an arbitrary amount of time in case we cannot use the device */
204 	if (local->suspended || !ieee802154_sdata_running(sdata)) {
205 		rcu_read_unlock();
206 		queue_delayed_work(local->mac_wq, &local->scan_work,
207 				   msecs_to_jiffies(1000));
208 		return;
209 	}
210 
211 	wpan_phy = scan_req->wpan_phy;
212 	scan_req_duration = scan_req->duration;
213 
214 	/* Look for the next valid chan */
215 	page = local->scan_page;
216 	channel = local->scan_channel;
217 	do {
218 		ret = mac802154_scan_find_next_chan(local, scan_req, page, &channel);
219 		if (ret) {
220 			rcu_read_unlock();
221 			goto end_scan;
222 		}
223 	} while (!ieee802154_chan_is_valid(scan_req->wpan_phy, page, channel));
224 
225 	rcu_read_unlock();
226 
227 	/* Bypass the stack on purpose when changing the channel */
228 	rtnl_lock();
229 	ret = drv_set_channel(local, page, channel);
230 	rtnl_unlock();
231 	if (ret) {
232 		dev_err(&sdata->dev->dev,
233 			"Channel change failure during scan, aborting (%d)\n", ret);
234 		goto end_scan;
235 	}
236 
237 	local->scan_page = page;
238 	local->scan_channel = channel;
239 
240 	rtnl_lock();
241 	ret = drv_start(local, IEEE802154_FILTERING_3_SCAN, &local->addr_filt);
242 	rtnl_unlock();
243 	if (ret) {
244 		dev_err(&sdata->dev->dev,
245 			"Restarting failure after channel change, aborting (%d)\n", ret);
246 		goto end_scan;
247 	}
248 
249 	if (scan_req->type == NL802154_SCAN_ACTIVE) {
250 		ret = mac802154_transmit_beacon_req(local, sdata);
251 		if (ret)
252 			dev_err(&sdata->dev->dev,
253 				"Error when transmitting beacon request (%d)\n", ret);
254 	}
255 
256 	ieee802154_configure_durations(wpan_phy, page, channel);
257 	scan_duration = mac802154_scan_get_channel_time(scan_req_duration,
258 							wpan_phy->symbol_duration);
259 	dev_dbg(&sdata->dev->dev,
260 		"Scan page %u channel %u for %ums\n",
261 		page, channel, jiffies_to_msecs(scan_duration));
262 	queue_delayed_work(local->mac_wq, &local->scan_work, scan_duration);
263 	return;
264 
265 end_scan:
266 	rtnl_lock();
267 	mac802154_scan_cleanup_locked(local, sdata, false);
268 	rtnl_unlock();
269 }
270 
271 int mac802154_trigger_scan_locked(struct ieee802154_sub_if_data *sdata,
272 				  struct cfg802154_scan_request *request)
273 {
274 	struct ieee802154_local *local = sdata->local;
275 
276 	ASSERT_RTNL();
277 
278 	if (mac802154_is_scanning(local))
279 		return -EBUSY;
280 
281 	if (request->type != NL802154_SCAN_PASSIVE &&
282 	    request->type != NL802154_SCAN_ACTIVE)
283 		return -EOPNOTSUPP;
284 
285 	/* Store scanning parameters */
286 	rcu_assign_pointer(local->scan_req, request);
287 
288 	/* Software scanning requires to set promiscuous mode, so we need to
289 	 * pause the Tx queue during the entire operation.
290 	 */
291 	ieee802154_mlme_op_pre(local);
292 
293 	sdata->required_filtering = IEEE802154_FILTERING_3_SCAN;
294 	local->scan_page = request->page;
295 	local->scan_channel = -1;
296 	set_bit(IEEE802154_IS_SCANNING, &local->ongoing);
297 	if (request->type == NL802154_SCAN_ACTIVE)
298 		mac802154_scan_prepare_beacon_req(local);
299 
300 	nl802154_scan_started(request->wpan_phy, request->wpan_dev);
301 
302 	queue_delayed_work(local->mac_wq, &local->scan_work, 0);
303 
304 	return 0;
305 }
306 
307 int mac802154_process_beacon(struct ieee802154_local *local,
308 			     struct sk_buff *skb,
309 			     u8 page, u8 channel)
310 {
311 	struct ieee802154_beacon_hdr *bh = (void *)skb->data;
312 	struct ieee802154_addr *src = &mac_cb(skb)->source;
313 	struct cfg802154_scan_request *scan_req;
314 	struct ieee802154_coord_desc desc;
315 
316 	if (skb->len != sizeof(*bh))
317 		return -EINVAL;
318 
319 	if (unlikely(src->mode == IEEE802154_ADDR_NONE))
320 		return -EINVAL;
321 
322 	dev_dbg(&skb->dev->dev,
323 		"BEACON received on page %u channel %u\n",
324 		page, channel);
325 
326 	memcpy(&desc.addr, src, sizeof(desc.addr));
327 	desc.page = page;
328 	desc.channel = channel;
329 	desc.link_quality = mac_cb(skb)->lqi;
330 	desc.superframe_spec = get_unaligned_le16(skb->data);
331 	desc.gts_permit = bh->gts_permit;
332 
333 	trace_802154_scan_event(&desc);
334 
335 	rcu_read_lock();
336 	scan_req = rcu_dereference(local->scan_req);
337 	if (likely(scan_req))
338 		nl802154_scan_event(scan_req->wpan_phy, scan_req->wpan_dev, &desc);
339 	rcu_read_unlock();
340 
341 	return 0;
342 }
343 
344 static int mac802154_transmit_beacon(struct ieee802154_local *local,
345 				     struct wpan_dev *wpan_dev)
346 {
347 	struct cfg802154_beacon_request *beacon_req;
348 	struct ieee802154_sub_if_data *sdata;
349 	struct sk_buff *skb;
350 	int ret;
351 
352 	/* Update the sequence number */
353 	local->beacon.mhr.seq = atomic_inc_return(&wpan_dev->bsn) & 0xFF;
354 
355 	skb = alloc_skb(IEEE802154_BEACON_SKB_SZ, GFP_KERNEL);
356 	if (!skb)
357 		return -ENOBUFS;
358 
359 	rcu_read_lock();
360 	beacon_req = rcu_dereference(local->beacon_req);
361 	if (unlikely(!beacon_req)) {
362 		rcu_read_unlock();
363 		kfree_skb(skb);
364 		return -EINVAL;
365 	}
366 
367 	sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(beacon_req->wpan_dev);
368 	skb->dev = sdata->dev;
369 
370 	rcu_read_unlock();
371 
372 	ret = ieee802154_beacon_push(skb, &local->beacon);
373 	if (ret) {
374 		kfree_skb(skb);
375 		return ret;
376 	}
377 
378 	/* Using the MLME transmission helper for sending beacons is a bit
379 	 * overkill because we do not really care about the final outcome.
380 	 *
381 	 * Even though, going through the whole net stack with a regular
382 	 * dev_queue_xmit() is not relevant either because we want beacons to be
383 	 * sent "now" rather than go through the whole net stack scheduling
384 	 * (qdisc & co).
385 	 *
386 	 * Finally, using ieee802154_subif_start_xmit() would only be an option
387 	 * if we had a generic transmit helper which would acquire the
388 	 * HARD_TX_LOCK() to prevent buffer handling conflicts with regular
389 	 * packets.
390 	 *
391 	 * So for now we keep it simple and send beacons with our MLME helper,
392 	 * even if it stops the ieee802154 queue entirely during these
393 	 * transmissions, wich anyway does not have a huge impact on the
394 	 * performances given the current design of the stack.
395 	 */
396 	return ieee802154_mlme_tx(local, sdata, skb);
397 }
398 
399 void mac802154_beacon_worker(struct work_struct *work)
400 {
401 	struct ieee802154_local *local =
402 		container_of(work, struct ieee802154_local, beacon_work.work);
403 	struct cfg802154_beacon_request *beacon_req;
404 	struct ieee802154_sub_if_data *sdata;
405 	struct wpan_dev *wpan_dev;
406 	u8 interval;
407 	int ret;
408 
409 	rcu_read_lock();
410 	beacon_req = rcu_dereference(local->beacon_req);
411 	if (unlikely(!beacon_req)) {
412 		rcu_read_unlock();
413 		return;
414 	}
415 
416 	sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(beacon_req->wpan_dev);
417 
418 	/* Wait an arbitrary amount of time in case we cannot use the device */
419 	if (local->suspended || !ieee802154_sdata_running(sdata)) {
420 		rcu_read_unlock();
421 		queue_delayed_work(local->mac_wq, &local->beacon_work,
422 				   msecs_to_jiffies(1000));
423 		return;
424 	}
425 
426 	wpan_dev = beacon_req->wpan_dev;
427 	interval = beacon_req->interval;
428 
429 	rcu_read_unlock();
430 
431 	dev_dbg(&sdata->dev->dev, "Sending beacon\n");
432 	ret = mac802154_transmit_beacon(local, wpan_dev);
433 	if (ret)
434 		dev_err(&sdata->dev->dev,
435 			"Beacon could not be transmitted (%d)\n", ret);
436 
437 	if (interval < IEEE802154_ACTIVE_SCAN_DURATION)
438 		queue_delayed_work(local->mac_wq, &local->beacon_work,
439 				   local->beacon_interval);
440 }
441 
442 int mac802154_stop_beacons_locked(struct ieee802154_local *local,
443 				  struct ieee802154_sub_if_data *sdata)
444 {
445 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
446 	struct cfg802154_beacon_request *request;
447 
448 	ASSERT_RTNL();
449 
450 	if (!mac802154_is_beaconing(local))
451 		return -ESRCH;
452 
453 	clear_bit(IEEE802154_IS_BEACONING, &local->ongoing);
454 	cancel_delayed_work(&local->beacon_work);
455 	request = rcu_replace_pointer(local->beacon_req, NULL, 1);
456 	if (!request)
457 		return 0;
458 	kvfree_rcu_mightsleep(request);
459 
460 	nl802154_beaconing_done(wpan_dev);
461 
462 	return 0;
463 }
464 
465 int mac802154_send_beacons_locked(struct ieee802154_sub_if_data *sdata,
466 				  struct cfg802154_beacon_request *request)
467 {
468 	struct ieee802154_local *local = sdata->local;
469 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
470 
471 	ASSERT_RTNL();
472 
473 	if (mac802154_is_beaconing(local))
474 		mac802154_stop_beacons_locked(local, sdata);
475 
476 	/* Store beaconing parameters */
477 	rcu_assign_pointer(local->beacon_req, request);
478 
479 	set_bit(IEEE802154_IS_BEACONING, &local->ongoing);
480 
481 	memset(&local->beacon, 0, sizeof(local->beacon));
482 	local->beacon.mhr.fc.type = IEEE802154_FC_TYPE_BEACON;
483 	local->beacon.mhr.fc.security_enabled = 0;
484 	local->beacon.mhr.fc.frame_pending = 0;
485 	local->beacon.mhr.fc.ack_request = 0;
486 	local->beacon.mhr.fc.intra_pan = 0;
487 	local->beacon.mhr.fc.dest_addr_mode = IEEE802154_NO_ADDRESSING;
488 	local->beacon.mhr.fc.version = IEEE802154_2003_STD;
489 	local->beacon.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
490 	atomic_set(&request->wpan_dev->bsn, -1);
491 	local->beacon.mhr.source.mode = IEEE802154_ADDR_LONG;
492 	local->beacon.mhr.source.pan_id = request->wpan_dev->pan_id;
493 	local->beacon.mhr.source.extended_addr = request->wpan_dev->extended_addr;
494 	local->beacon.mac_pl.beacon_order = request->interval;
495 	if (request->interval <= IEEE802154_MAX_SCAN_DURATION)
496 		local->beacon.mac_pl.superframe_order = request->interval;
497 	local->beacon.mac_pl.final_cap_slot = 0xf;
498 	local->beacon.mac_pl.battery_life_ext = 0;
499 	local->beacon.mac_pl.pan_coordinator = !wpan_dev->parent;
500 	local->beacon.mac_pl.assoc_permit = 1;
501 
502 	if (request->interval == IEEE802154_ACTIVE_SCAN_DURATION)
503 		return 0;
504 
505 	/* Start the beacon work */
506 	local->beacon_interval =
507 		mac802154_scan_get_channel_time(request->interval,
508 						request->wpan_phy->symbol_duration);
509 	queue_delayed_work(local->mac_wq, &local->beacon_work, 0);
510 
511 	return 0;
512 }
513 
514 int mac802154_perform_association(struct ieee802154_sub_if_data *sdata,
515 				  struct ieee802154_pan_device *coord,
516 				  __le16 *short_addr)
517 {
518 	u64 ceaddr = swab64((__force u64)coord->extended_addr);
519 	struct ieee802154_association_req_frame frame = {};
520 	struct ieee802154_local *local = sdata->local;
521 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
522 	struct sk_buff *skb;
523 	int ret;
524 
525 	frame.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
526 	frame.mhr.fc.security_enabled = 0;
527 	frame.mhr.fc.frame_pending = 0;
528 	frame.mhr.fc.ack_request = 1; /* We always expect an ack here */
529 	frame.mhr.fc.intra_pan = 0;
530 	frame.mhr.fc.dest_addr_mode = (coord->mode == IEEE802154_ADDR_LONG) ?
531 		IEEE802154_EXTENDED_ADDRESSING : IEEE802154_SHORT_ADDRESSING;
532 	frame.mhr.fc.version = IEEE802154_2003_STD;
533 	frame.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
534 	frame.mhr.source.mode = IEEE802154_ADDR_LONG;
535 	frame.mhr.source.pan_id = cpu_to_le16(IEEE802154_PANID_BROADCAST);
536 	frame.mhr.source.extended_addr = wpan_dev->extended_addr;
537 	frame.mhr.dest.mode = coord->mode;
538 	frame.mhr.dest.pan_id = coord->pan_id;
539 	if (coord->mode == IEEE802154_ADDR_LONG)
540 		frame.mhr.dest.extended_addr = coord->extended_addr;
541 	else
542 		frame.mhr.dest.short_addr = coord->short_addr;
543 	frame.mhr.seq = atomic_inc_return(&wpan_dev->dsn) & 0xFF;
544 	frame.mac_pl.cmd_id = IEEE802154_CMD_ASSOCIATION_REQ;
545 	frame.assoc_req_pl.device_type = 1;
546 	frame.assoc_req_pl.power_source = 1;
547 	frame.assoc_req_pl.rx_on_when_idle = 1;
548 	frame.assoc_req_pl.alloc_addr = 1;
549 
550 	skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ + sizeof(frame.assoc_req_pl),
551 			GFP_KERNEL);
552 	if (!skb)
553 		return -ENOBUFS;
554 
555 	skb->dev = sdata->dev;
556 
557 	ret = ieee802154_mac_cmd_push(skb, &frame, &frame.assoc_req_pl,
558 				      sizeof(frame.assoc_req_pl));
559 	if (ret) {
560 		kfree_skb(skb);
561 		return ret;
562 	}
563 
564 	local->assoc_dev = coord;
565 	reinit_completion(&local->assoc_done);
566 	set_bit(IEEE802154_IS_ASSOCIATING, &local->ongoing);
567 
568 	ret = ieee802154_mlme_tx_one_locked(local, sdata, skb);
569 	if (ret) {
570 		if (ret > 0)
571 			ret = (ret == IEEE802154_NO_ACK) ? -EREMOTEIO : -EIO;
572 		dev_warn(&sdata->dev->dev,
573 			 "No ASSOC REQ ACK received from %8phC\n", &ceaddr);
574 		goto clear_assoc;
575 	}
576 
577 	ret = wait_for_completion_killable_timeout(&local->assoc_done, 10 * HZ);
578 	if (ret <= 0) {
579 		dev_warn(&sdata->dev->dev,
580 			 "No ASSOC RESP received from %8phC\n", &ceaddr);
581 		ret = -ETIMEDOUT;
582 		goto clear_assoc;
583 	}
584 
585 	if (local->assoc_status != IEEE802154_ASSOCIATION_SUCCESSFUL) {
586 		if (local->assoc_status == IEEE802154_PAN_AT_CAPACITY)
587 			ret = -ERANGE;
588 		else
589 			ret = -EPERM;
590 
591 		dev_warn(&sdata->dev->dev,
592 			 "Negative ASSOC RESP received from %8phC: %s\n", &ceaddr,
593 			 local->assoc_status == IEEE802154_PAN_AT_CAPACITY ?
594 			 "PAN at capacity" : "access denied");
595 	}
596 
597 	ret = 0;
598 	*short_addr = local->assoc_addr;
599 
600 clear_assoc:
601 	clear_bit(IEEE802154_IS_ASSOCIATING, &local->ongoing);
602 	local->assoc_dev = NULL;
603 
604 	return ret;
605 }
606 
607 int mac802154_process_association_resp(struct ieee802154_sub_if_data *sdata,
608 				       struct sk_buff *skb)
609 {
610 	struct ieee802154_addr *src = &mac_cb(skb)->source;
611 	struct ieee802154_addr *dest = &mac_cb(skb)->dest;
612 	u64 deaddr = swab64((__force u64)dest->extended_addr);
613 	struct ieee802154_local *local = sdata->local;
614 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
615 	struct ieee802154_assoc_resp_pl resp_pl = {};
616 
617 	if (skb->len != sizeof(resp_pl))
618 		return -EINVAL;
619 
620 	if (unlikely(src->mode != IEEE802154_EXTENDED_ADDRESSING ||
621 		     dest->mode != IEEE802154_EXTENDED_ADDRESSING))
622 		return -EINVAL;
623 
624 	if (unlikely(dest->extended_addr != wpan_dev->extended_addr ||
625 		     src->extended_addr != local->assoc_dev->extended_addr))
626 		return -ENODEV;
627 
628 	memcpy(&resp_pl, skb->data, sizeof(resp_pl));
629 	local->assoc_addr = resp_pl.short_addr;
630 	local->assoc_status = resp_pl.status;
631 
632 	dev_dbg(&skb->dev->dev,
633 		"ASSOC RESP 0x%x received from %8phC, getting short address %04x\n",
634 		local->assoc_status, &deaddr, local->assoc_addr);
635 
636 	complete(&local->assoc_done);
637 
638 	return 0;
639 }
640 
641 int mac802154_send_disassociation_notif(struct ieee802154_sub_if_data *sdata,
642 					struct ieee802154_pan_device *target,
643 					u8 reason)
644 {
645 	struct ieee802154_disassociation_notif_frame frame = {};
646 	u64 teaddr = swab64((__force u64)target->extended_addr);
647 	struct ieee802154_local *local = sdata->local;
648 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
649 	struct sk_buff *skb;
650 	int ret;
651 
652 	frame.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
653 	frame.mhr.fc.security_enabled = 0;
654 	frame.mhr.fc.frame_pending = 0;
655 	frame.mhr.fc.ack_request = 1;
656 	frame.mhr.fc.intra_pan = 1;
657 	frame.mhr.fc.dest_addr_mode = (target->mode == IEEE802154_ADDR_LONG) ?
658 		IEEE802154_EXTENDED_ADDRESSING : IEEE802154_SHORT_ADDRESSING;
659 	frame.mhr.fc.version = IEEE802154_2003_STD;
660 	frame.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
661 	frame.mhr.source.mode = IEEE802154_ADDR_LONG;
662 	frame.mhr.source.pan_id = wpan_dev->pan_id;
663 	frame.mhr.source.extended_addr = wpan_dev->extended_addr;
664 	frame.mhr.dest.mode = target->mode;
665 	frame.mhr.dest.pan_id = wpan_dev->pan_id;
666 	if (target->mode == IEEE802154_ADDR_LONG)
667 		frame.mhr.dest.extended_addr = target->extended_addr;
668 	else
669 		frame.mhr.dest.short_addr = target->short_addr;
670 	frame.mhr.seq = atomic_inc_return(&wpan_dev->dsn) & 0xFF;
671 	frame.mac_pl.cmd_id = IEEE802154_CMD_DISASSOCIATION_NOTIFY;
672 	frame.disassoc_pl = reason;
673 
674 	skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ + sizeof(frame.disassoc_pl),
675 			GFP_KERNEL);
676 	if (!skb)
677 		return -ENOBUFS;
678 
679 	skb->dev = sdata->dev;
680 
681 	ret = ieee802154_mac_cmd_push(skb, &frame, &frame.disassoc_pl,
682 				      sizeof(frame.disassoc_pl));
683 	if (ret) {
684 		kfree_skb(skb);
685 		return ret;
686 	}
687 
688 	ret = ieee802154_mlme_tx_one_locked(local, sdata, skb);
689 	if (ret) {
690 		dev_warn(&sdata->dev->dev,
691 			 "No DISASSOC ACK received from %8phC\n", &teaddr);
692 		if (ret > 0)
693 			ret = (ret == IEEE802154_NO_ACK) ? -EREMOTEIO : -EIO;
694 		return ret;
695 	}
696 
697 	dev_dbg(&sdata->dev->dev, "DISASSOC ACK received from %8phC\n", &teaddr);
698 	return 0;
699 }
700 
701 static int
702 mac802154_send_association_resp_locked(struct ieee802154_sub_if_data *sdata,
703 				       struct ieee802154_pan_device *target,
704 				       struct ieee802154_assoc_resp_pl *assoc_resp_pl)
705 {
706 	u64 teaddr = swab64((__force u64)target->extended_addr);
707 	struct ieee802154_association_resp_frame frame = {};
708 	struct ieee802154_local *local = sdata->local;
709 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
710 	struct sk_buff *skb;
711 	int ret;
712 
713 	frame.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
714 	frame.mhr.fc.security_enabled = 0;
715 	frame.mhr.fc.frame_pending = 0;
716 	frame.mhr.fc.ack_request = 1; /* We always expect an ack here */
717 	frame.mhr.fc.intra_pan = 1;
718 	frame.mhr.fc.dest_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
719 	frame.mhr.fc.version = IEEE802154_2003_STD;
720 	frame.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
721 	frame.mhr.source.mode = IEEE802154_ADDR_LONG;
722 	frame.mhr.source.extended_addr = wpan_dev->extended_addr;
723 	frame.mhr.dest.mode = IEEE802154_ADDR_LONG;
724 	frame.mhr.dest.pan_id = wpan_dev->pan_id;
725 	frame.mhr.dest.extended_addr = target->extended_addr;
726 	frame.mhr.seq = atomic_inc_return(&wpan_dev->dsn) & 0xFF;
727 	frame.mac_pl.cmd_id = IEEE802154_CMD_ASSOCIATION_RESP;
728 
729 	skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ + sizeof(*assoc_resp_pl),
730 			GFP_KERNEL);
731 	if (!skb)
732 		return -ENOBUFS;
733 
734 	skb->dev = sdata->dev;
735 
736 	ret = ieee802154_mac_cmd_push(skb, &frame, assoc_resp_pl,
737 				      sizeof(*assoc_resp_pl));
738 	if (ret) {
739 		kfree_skb(skb);
740 		return ret;
741 	}
742 
743 	ret = ieee802154_mlme_tx_locked(local, sdata, skb);
744 	if (ret) {
745 		dev_warn(&sdata->dev->dev,
746 			 "No ASSOC RESP ACK received from %8phC\n", &teaddr);
747 		if (ret > 0)
748 			ret = (ret == IEEE802154_NO_ACK) ? -EREMOTEIO : -EIO;
749 		return ret;
750 	}
751 
752 	return 0;
753 }
754 
755 int mac802154_process_association_req(struct ieee802154_sub_if_data *sdata,
756 				      struct sk_buff *skb)
757 {
758 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
759 	struct ieee802154_addr *src = &mac_cb(skb)->source;
760 	struct ieee802154_addr *dest = &mac_cb(skb)->dest;
761 	struct ieee802154_assoc_resp_pl assoc_resp_pl = {};
762 	struct ieee802154_assoc_req_pl assoc_req_pl;
763 	struct ieee802154_pan_device *child, *exchild;
764 	struct ieee802154_addr tmp = {};
765 	u64 ceaddr;
766 	int ret;
767 
768 	if (skb->len != sizeof(assoc_req_pl))
769 		return -EINVAL;
770 
771 	if (unlikely(src->mode != IEEE802154_EXTENDED_ADDRESSING))
772 		return -EINVAL;
773 
774 	if (unlikely(dest->pan_id != wpan_dev->pan_id))
775 		return -ENODEV;
776 
777 	if (dest->mode == IEEE802154_EXTENDED_ADDRESSING &&
778 	    unlikely(dest->extended_addr != wpan_dev->extended_addr))
779 		return -ENODEV;
780 	else if (dest->mode == IEEE802154_SHORT_ADDRESSING &&
781 		 unlikely(dest->short_addr != wpan_dev->short_addr))
782 		return -ENODEV;
783 
784 	if (wpan_dev->parent) {
785 		dev_dbg(&sdata->dev->dev,
786 			"Ignoring ASSOC REQ, not the PAN coordinator\n");
787 		return -ENODEV;
788 	}
789 
790 	mutex_lock(&wpan_dev->association_lock);
791 
792 	memcpy(&assoc_req_pl, skb->data, sizeof(assoc_req_pl));
793 	if (assoc_req_pl.assoc_type) {
794 		dev_err(&skb->dev->dev, "Fast associations not supported yet\n");
795 		ret = -EOPNOTSUPP;
796 		goto unlock;
797 	}
798 
799 	child = kzalloc(sizeof(*child), GFP_KERNEL);
800 	if (!child) {
801 		ret = -ENOMEM;
802 		goto unlock;
803 	}
804 
805 	child->extended_addr = src->extended_addr;
806 	child->mode = IEEE802154_EXTENDED_ADDRESSING;
807 	ceaddr = swab64((__force u64)child->extended_addr);
808 
809 	if (wpan_dev->nchildren >= wpan_dev->max_associations) {
810 		if (!wpan_dev->max_associations)
811 			assoc_resp_pl.status = IEEE802154_PAN_ACCESS_DENIED;
812 		else
813 			assoc_resp_pl.status = IEEE802154_PAN_AT_CAPACITY;
814 		assoc_resp_pl.short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_BROADCAST);
815 		dev_dbg(&sdata->dev->dev,
816 			"Refusing ASSOC REQ from child %8phC, %s\n", &ceaddr,
817 			assoc_resp_pl.status == IEEE802154_PAN_ACCESS_DENIED ?
818 			"access denied" : "too many children");
819 	} else {
820 		assoc_resp_pl.status = IEEE802154_ASSOCIATION_SUCCESSFUL;
821 		if (assoc_req_pl.alloc_addr) {
822 			assoc_resp_pl.short_addr = cfg802154_get_free_short_addr(wpan_dev);
823 			child->mode = IEEE802154_SHORT_ADDRESSING;
824 		} else {
825 			assoc_resp_pl.short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
826 		}
827 		child->short_addr = assoc_resp_pl.short_addr;
828 		dev_dbg(&sdata->dev->dev,
829 			"Accepting ASSOC REQ from child %8phC, providing short address 0x%04x\n",
830 			&ceaddr, le16_to_cpu(child->short_addr));
831 	}
832 
833 	ret = mac802154_send_association_resp_locked(sdata, child, &assoc_resp_pl);
834 	if (ret || assoc_resp_pl.status != IEEE802154_ASSOCIATION_SUCCESSFUL) {
835 		kfree(child);
836 		goto unlock;
837 	}
838 
839 	dev_dbg(&sdata->dev->dev,
840 		"Successful association with new child %8phC\n", &ceaddr);
841 
842 	/* Ensure this child is not already associated (might happen due to
843 	 * retransmissions), in this case drop the ex structure.
844 	 */
845 	tmp.mode = child->mode;
846 	tmp.extended_addr = child->extended_addr;
847 	exchild = cfg802154_device_is_child(wpan_dev, &tmp);
848 	if (exchild) {
849 		dev_dbg(&sdata->dev->dev,
850 			"Child %8phC was already known\n", &ceaddr);
851 		list_del(&exchild->node);
852 	}
853 
854 	list_add(&child->node, &wpan_dev->children);
855 	wpan_dev->nchildren++;
856 
857 unlock:
858 	mutex_unlock(&wpan_dev->association_lock);
859 	return ret;
860 }
861 
862 int mac802154_process_disassociation_notif(struct ieee802154_sub_if_data *sdata,
863 					   struct sk_buff *skb)
864 {
865 	struct ieee802154_addr *src = &mac_cb(skb)->source;
866 	struct ieee802154_addr *dest = &mac_cb(skb)->dest;
867 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
868 	struct ieee802154_pan_device *child;
869 	struct ieee802154_addr target;
870 	bool parent;
871 	u64 teaddr;
872 
873 	if (skb->len != sizeof(u8))
874 		return -EINVAL;
875 
876 	if (unlikely(src->mode != IEEE802154_EXTENDED_ADDRESSING))
877 		return -EINVAL;
878 
879 	if (dest->mode == IEEE802154_EXTENDED_ADDRESSING &&
880 	    unlikely(dest->extended_addr != wpan_dev->extended_addr))
881 		return -ENODEV;
882 	else if (dest->mode == IEEE802154_SHORT_ADDRESSING &&
883 		 unlikely(dest->short_addr != wpan_dev->short_addr))
884 		return -ENODEV;
885 
886 	if (dest->pan_id != wpan_dev->pan_id)
887 		return -ENODEV;
888 
889 	target.mode = IEEE802154_EXTENDED_ADDRESSING;
890 	target.extended_addr = src->extended_addr;
891 	teaddr = swab64((__force u64)target.extended_addr);
892 	dev_dbg(&skb->dev->dev, "Processing DISASSOC NOTIF from %8phC\n", &teaddr);
893 
894 	mutex_lock(&wpan_dev->association_lock);
895 	parent = cfg802154_device_is_parent(wpan_dev, &target);
896 	if (!parent)
897 		child = cfg802154_device_is_child(wpan_dev, &target);
898 	if (!parent && !child) {
899 		mutex_unlock(&wpan_dev->association_lock);
900 		return -EINVAL;
901 	}
902 
903 	if (parent) {
904 		kfree(wpan_dev->parent);
905 		wpan_dev->parent = NULL;
906 	} else {
907 		list_del(&child->node);
908 		kfree(child);
909 		wpan_dev->nchildren--;
910 	}
911 
912 	mutex_unlock(&wpan_dev->association_lock);
913 
914 	return 0;
915 }
916