xref: /linux/net/mac802154/scan.c (revision a10ea943356b9d70c5616a0a06f6fa97cfdaccb1)
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 	enum nl802154_scan_types scan_req_type;
180 	struct ieee802154_sub_if_data *sdata;
181 	unsigned int scan_duration = 0;
182 	netdevice_tracker dev_tracker;
183 	struct wpan_phy *wpan_phy;
184 	u8 scan_req_duration;
185 	u8 page, channel;
186 	int ret;
187 
188 	/* Ensure the device receiver is turned off when changing channels
189 	 * because there is no atomic way to change the channel and know on
190 	 * which one a beacon might have been received.
191 	 */
192 	drv_stop(local);
193 	synchronize_net();
194 	mac802154_flush_queued_beacons(local);
195 
196 	rcu_read_lock();
197 	scan_req = rcu_dereference(local->scan_req);
198 	if (unlikely(!scan_req)) {
199 		rcu_read_unlock();
200 		return;
201 	}
202 
203 	sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(scan_req->wpan_dev);
204 
205 	/* Wait an arbitrary amount of time in case we cannot use the device */
206 	if (local->suspended || !ieee802154_sdata_running(sdata)) {
207 		rcu_read_unlock();
208 		queue_delayed_work(local->mac_wq, &local->scan_work,
209 				   msecs_to_jiffies(1000));
210 		return;
211 	}
212 
213 	/*
214 	 * sdata->dev is dereferenced below after rcu_read_unlock() and outside
215 	 * the rtnl, and a concurrent DEL_INTERFACE / PHY teardown can free it
216 	 * asynchronously from netdev_run_todo(). Pin it with a reference taken
217 	 * while the RCU read lock is still held, and drop it at every exit.
218 	 */
219 	netdev_hold(sdata->dev, &dev_tracker, GFP_ATOMIC);
220 
221 	wpan_phy = scan_req->wpan_phy;
222 	scan_req_type = scan_req->type;
223 	scan_req_duration = scan_req->duration;
224 
225 	/* Look for the next valid chan */
226 	page = local->scan_page;
227 	channel = local->scan_channel;
228 	do {
229 		ret = mac802154_scan_find_next_chan(local, scan_req, page, &channel);
230 		if (ret) {
231 			rcu_read_unlock();
232 			goto end_scan;
233 		}
234 	} while (!ieee802154_chan_is_valid(scan_req->wpan_phy, page, channel));
235 
236 	rcu_read_unlock();
237 
238 	/* Bypass the stack on purpose when changing the channel */
239 	rtnl_lock();
240 	ret = drv_set_channel(local, page, channel);
241 	rtnl_unlock();
242 	if (ret) {
243 		dev_err(&sdata->dev->dev,
244 			"Channel change failure during scan, aborting (%d)\n", ret);
245 		goto end_scan;
246 	}
247 
248 	local->scan_page = page;
249 	local->scan_channel = channel;
250 
251 	rtnl_lock();
252 	ret = drv_start(local, IEEE802154_FILTERING_3_SCAN, &local->addr_filt);
253 	rtnl_unlock();
254 	if (ret) {
255 		dev_err(&sdata->dev->dev,
256 			"Restarting failure after channel change, aborting (%d)\n", ret);
257 		goto end_scan;
258 	}
259 
260 	if (scan_req_type == NL802154_SCAN_ACTIVE) {
261 		ret = mac802154_transmit_beacon_req(local, sdata);
262 		if (ret)
263 			dev_err(&sdata->dev->dev,
264 				"Error when transmitting beacon request (%d)\n", ret);
265 	}
266 
267 	ieee802154_configure_durations(wpan_phy, page, channel);
268 	scan_duration = mac802154_scan_get_channel_time(scan_req_duration,
269 							wpan_phy->symbol_duration);
270 	dev_dbg(&sdata->dev->dev,
271 		"Scan page %u channel %u for %ums\n",
272 		page, channel, jiffies_to_msecs(scan_duration));
273 	queue_delayed_work(local->mac_wq, &local->scan_work, scan_duration);
274 	netdev_put(sdata->dev, &dev_tracker);
275 	return;
276 
277 end_scan:
278 	rtnl_lock();
279 	mac802154_scan_cleanup_locked(local, sdata, false);
280 	rtnl_unlock();
281 	netdev_put(sdata->dev, &dev_tracker);
282 }
283 
284 int mac802154_trigger_scan_locked(struct ieee802154_sub_if_data *sdata,
285 				  struct cfg802154_scan_request *request)
286 {
287 	struct ieee802154_local *local = sdata->local;
288 
289 	ASSERT_RTNL();
290 
291 	if (mac802154_is_scanning(local))
292 		return -EBUSY;
293 
294 	if (request->type != NL802154_SCAN_PASSIVE &&
295 	    request->type != NL802154_SCAN_ACTIVE)
296 		return -EOPNOTSUPP;
297 
298 	/* Store scanning parameters */
299 	rcu_assign_pointer(local->scan_req, request);
300 
301 	/* Software scanning requires to set promiscuous mode, so we need to
302 	 * pause the Tx queue during the entire operation.
303 	 */
304 	ieee802154_mlme_op_pre(local);
305 
306 	sdata->required_filtering = IEEE802154_FILTERING_3_SCAN;
307 	local->scan_page = request->page;
308 	local->scan_channel = -1;
309 	set_bit(IEEE802154_IS_SCANNING, &local->ongoing);
310 	if (request->type == NL802154_SCAN_ACTIVE)
311 		mac802154_scan_prepare_beacon_req(local);
312 
313 	nl802154_scan_started(request->wpan_phy, request->wpan_dev);
314 
315 	queue_delayed_work(local->mac_wq, &local->scan_work, 0);
316 
317 	return 0;
318 }
319 
320 int mac802154_process_beacon(struct ieee802154_local *local,
321 			     struct sk_buff *skb,
322 			     u8 page, u8 channel)
323 {
324 	struct ieee802154_beacon_hdr *bh = (void *)skb->data;
325 	struct ieee802154_addr *src = &mac_cb(skb)->source;
326 	struct cfg802154_scan_request *scan_req;
327 	struct ieee802154_coord_desc desc;
328 
329 	if (skb->len != sizeof(*bh))
330 		return -EINVAL;
331 
332 	if (unlikely(src->mode == IEEE802154_ADDR_NONE))
333 		return -EINVAL;
334 
335 	dev_dbg(&skb->dev->dev,
336 		"BEACON received on page %u channel %u\n",
337 		page, channel);
338 
339 	memcpy(&desc.addr, src, sizeof(desc.addr));
340 	desc.page = page;
341 	desc.channel = channel;
342 	desc.link_quality = mac_cb(skb)->lqi;
343 	desc.superframe_spec = get_unaligned_le16(skb->data);
344 	desc.gts_permit = bh->gts_permit;
345 
346 	trace_802154_scan_event(&desc);
347 
348 	rcu_read_lock();
349 	scan_req = rcu_dereference(local->scan_req);
350 	if (likely(scan_req))
351 		nl802154_scan_event(scan_req->wpan_phy, scan_req->wpan_dev, &desc);
352 	rcu_read_unlock();
353 
354 	return 0;
355 }
356 
357 static int mac802154_transmit_beacon(struct ieee802154_local *local,
358 				     struct wpan_dev *wpan_dev)
359 {
360 	struct cfg802154_beacon_request *beacon_req;
361 	struct ieee802154_sub_if_data *sdata;
362 	struct sk_buff *skb;
363 	int ret;
364 
365 	/* Update the sequence number */
366 	local->beacon.mhr.seq = atomic_inc_return(&wpan_dev->bsn) & 0xFF;
367 
368 	skb = alloc_skb(IEEE802154_BEACON_SKB_SZ, GFP_KERNEL);
369 	if (!skb)
370 		return -ENOBUFS;
371 
372 	rcu_read_lock();
373 	beacon_req = rcu_dereference(local->beacon_req);
374 	if (unlikely(!beacon_req)) {
375 		rcu_read_unlock();
376 		kfree_skb(skb);
377 		return -EINVAL;
378 	}
379 
380 	sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(beacon_req->wpan_dev);
381 	skb->dev = sdata->dev;
382 
383 	rcu_read_unlock();
384 
385 	ret = ieee802154_beacon_push(skb, &local->beacon);
386 	if (ret) {
387 		kfree_skb(skb);
388 		return ret;
389 	}
390 
391 	/* Using the MLME transmission helper for sending beacons is a bit
392 	 * overkill because we do not really care about the final outcome.
393 	 *
394 	 * Even though, going through the whole net stack with a regular
395 	 * dev_queue_xmit() is not relevant either because we want beacons to be
396 	 * sent "now" rather than go through the whole net stack scheduling
397 	 * (qdisc & co).
398 	 *
399 	 * Finally, using ieee802154_subif_start_xmit() would only be an option
400 	 * if we had a generic transmit helper which would acquire the
401 	 * HARD_TX_LOCK() to prevent buffer handling conflicts with regular
402 	 * packets.
403 	 *
404 	 * So for now we keep it simple and send beacons with our MLME helper,
405 	 * even if it stops the ieee802154 queue entirely during these
406 	 * transmissions, wich anyway does not have a huge impact on the
407 	 * performances given the current design of the stack.
408 	 */
409 	return ieee802154_mlme_tx(local, sdata, skb);
410 }
411 
412 void mac802154_beacon_worker(struct work_struct *work)
413 {
414 	struct ieee802154_local *local =
415 		container_of(work, struct ieee802154_local, beacon_work.work);
416 	struct cfg802154_beacon_request *beacon_req;
417 	struct ieee802154_sub_if_data *sdata;
418 	struct wpan_dev *wpan_dev;
419 	u8 interval;
420 	int ret;
421 
422 	rcu_read_lock();
423 	beacon_req = rcu_dereference(local->beacon_req);
424 	if (unlikely(!beacon_req)) {
425 		rcu_read_unlock();
426 		return;
427 	}
428 
429 	sdata = IEEE802154_WPAN_DEV_TO_SUB_IF(beacon_req->wpan_dev);
430 
431 	/* Wait an arbitrary amount of time in case we cannot use the device */
432 	if (local->suspended || !ieee802154_sdata_running(sdata)) {
433 		rcu_read_unlock();
434 		queue_delayed_work(local->mac_wq, &local->beacon_work,
435 				   msecs_to_jiffies(1000));
436 		return;
437 	}
438 
439 	wpan_dev = beacon_req->wpan_dev;
440 	interval = beacon_req->interval;
441 
442 	rcu_read_unlock();
443 
444 	dev_dbg(&sdata->dev->dev, "Sending beacon\n");
445 	ret = mac802154_transmit_beacon(local, wpan_dev);
446 	if (ret)
447 		dev_err(&sdata->dev->dev,
448 			"Beacon could not be transmitted (%d)\n", ret);
449 
450 	if (interval < IEEE802154_ACTIVE_SCAN_DURATION)
451 		queue_delayed_work(local->mac_wq, &local->beacon_work,
452 				   local->beacon_interval);
453 }
454 
455 int mac802154_stop_beacons_locked(struct ieee802154_local *local,
456 				  struct ieee802154_sub_if_data *sdata)
457 {
458 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
459 	struct cfg802154_beacon_request *request;
460 
461 	ASSERT_RTNL();
462 
463 	if (!mac802154_is_beaconing(local))
464 		return -ESRCH;
465 
466 	clear_bit(IEEE802154_IS_BEACONING, &local->ongoing);
467 	cancel_delayed_work(&local->beacon_work);
468 	request = rcu_replace_pointer(local->beacon_req, NULL, 1);
469 	if (!request)
470 		return 0;
471 	kvfree_rcu_mightsleep(request);
472 
473 	nl802154_beaconing_done(wpan_dev);
474 
475 	return 0;
476 }
477 
478 int mac802154_send_beacons_locked(struct ieee802154_sub_if_data *sdata,
479 				  struct cfg802154_beacon_request *request)
480 {
481 	struct ieee802154_local *local = sdata->local;
482 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
483 
484 	ASSERT_RTNL();
485 
486 	if (mac802154_is_beaconing(local))
487 		mac802154_stop_beacons_locked(local, sdata);
488 
489 	/* Store beaconing parameters */
490 	rcu_assign_pointer(local->beacon_req, request);
491 
492 	set_bit(IEEE802154_IS_BEACONING, &local->ongoing);
493 
494 	memset(&local->beacon, 0, sizeof(local->beacon));
495 	local->beacon.mhr.fc.type = IEEE802154_FC_TYPE_BEACON;
496 	local->beacon.mhr.fc.security_enabled = 0;
497 	local->beacon.mhr.fc.frame_pending = 0;
498 	local->beacon.mhr.fc.ack_request = 0;
499 	local->beacon.mhr.fc.intra_pan = 0;
500 	local->beacon.mhr.fc.dest_addr_mode = IEEE802154_NO_ADDRESSING;
501 	local->beacon.mhr.fc.version = IEEE802154_2003_STD;
502 	local->beacon.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
503 	atomic_set(&request->wpan_dev->bsn, -1);
504 	local->beacon.mhr.source.mode = IEEE802154_ADDR_LONG;
505 	local->beacon.mhr.source.pan_id = request->wpan_dev->pan_id;
506 	local->beacon.mhr.source.extended_addr = request->wpan_dev->extended_addr;
507 	local->beacon.mac_pl.beacon_order = request->interval;
508 	if (request->interval <= IEEE802154_MAX_SCAN_DURATION)
509 		local->beacon.mac_pl.superframe_order = request->interval;
510 	local->beacon.mac_pl.final_cap_slot = 0xf;
511 	local->beacon.mac_pl.battery_life_ext = 0;
512 	local->beacon.mac_pl.pan_coordinator = !wpan_dev->parent;
513 	local->beacon.mac_pl.assoc_permit = 1;
514 
515 	if (request->interval == IEEE802154_ACTIVE_SCAN_DURATION)
516 		return 0;
517 
518 	/* Start the beacon work */
519 	local->beacon_interval =
520 		mac802154_scan_get_channel_time(request->interval,
521 						request->wpan_phy->symbol_duration);
522 	queue_delayed_work(local->mac_wq, &local->beacon_work, 0);
523 
524 	return 0;
525 }
526 
527 int mac802154_perform_association(struct ieee802154_sub_if_data *sdata,
528 				  struct ieee802154_pan_device *coord,
529 				  __le16 *short_addr)
530 {
531 	u64 ceaddr = swab64((__force u64)coord->extended_addr);
532 	struct ieee802154_association_req_frame frame = {};
533 	struct ieee802154_local *local = sdata->local;
534 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
535 	struct sk_buff *skb;
536 	int ret;
537 
538 	frame.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
539 	frame.mhr.fc.security_enabled = 0;
540 	frame.mhr.fc.frame_pending = 0;
541 	frame.mhr.fc.ack_request = 1; /* We always expect an ack here */
542 	frame.mhr.fc.intra_pan = 0;
543 	frame.mhr.fc.dest_addr_mode = (coord->mode == IEEE802154_ADDR_LONG) ?
544 		IEEE802154_EXTENDED_ADDRESSING : IEEE802154_SHORT_ADDRESSING;
545 	frame.mhr.fc.version = IEEE802154_2003_STD;
546 	frame.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
547 	frame.mhr.source.mode = IEEE802154_ADDR_LONG;
548 	frame.mhr.source.pan_id = cpu_to_le16(IEEE802154_PANID_BROADCAST);
549 	frame.mhr.source.extended_addr = wpan_dev->extended_addr;
550 	frame.mhr.dest.mode = coord->mode;
551 	frame.mhr.dest.pan_id = coord->pan_id;
552 	if (coord->mode == IEEE802154_ADDR_LONG)
553 		frame.mhr.dest.extended_addr = coord->extended_addr;
554 	else
555 		frame.mhr.dest.short_addr = coord->short_addr;
556 	frame.mhr.seq = atomic_inc_return(&wpan_dev->dsn) & 0xFF;
557 	frame.mac_pl.cmd_id = IEEE802154_CMD_ASSOCIATION_REQ;
558 	frame.assoc_req_pl.device_type = 1;
559 	frame.assoc_req_pl.power_source = 1;
560 	frame.assoc_req_pl.rx_on_when_idle = 1;
561 	frame.assoc_req_pl.alloc_addr = 1;
562 
563 	skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ + sizeof(frame.assoc_req_pl),
564 			GFP_KERNEL);
565 	if (!skb)
566 		return -ENOBUFS;
567 
568 	skb->dev = sdata->dev;
569 
570 	ret = ieee802154_mac_cmd_push(skb, &frame, &frame.assoc_req_pl,
571 				      sizeof(frame.assoc_req_pl));
572 	if (ret) {
573 		kfree_skb(skb);
574 		return ret;
575 	}
576 
577 	local->assoc_dev = coord;
578 	reinit_completion(&local->assoc_done);
579 	set_bit(IEEE802154_IS_ASSOCIATING, &local->ongoing);
580 
581 	ret = ieee802154_mlme_tx_one_locked(local, sdata, skb);
582 	if (ret) {
583 		if (ret > 0)
584 			ret = (ret == IEEE802154_NO_ACK) ? -EREMOTEIO : -EIO;
585 		dev_warn(&sdata->dev->dev,
586 			 "No ASSOC REQ ACK received from %8phC\n", &ceaddr);
587 		goto clear_assoc;
588 	}
589 
590 	ret = wait_for_completion_killable_timeout(&local->assoc_done, 10 * HZ);
591 	if (ret <= 0) {
592 		dev_warn(&sdata->dev->dev,
593 			 "No ASSOC RESP received from %8phC\n", &ceaddr);
594 		ret = -ETIMEDOUT;
595 		goto clear_assoc;
596 	}
597 
598 	if (local->assoc_status != IEEE802154_ASSOCIATION_SUCCESSFUL) {
599 		if (local->assoc_status == IEEE802154_PAN_AT_CAPACITY)
600 			ret = -ERANGE;
601 		else
602 			ret = -EPERM;
603 
604 		dev_warn(&sdata->dev->dev,
605 			 "Negative ASSOC RESP received from %8phC: %s\n", &ceaddr,
606 			 local->assoc_status == IEEE802154_PAN_AT_CAPACITY ?
607 			 "PAN at capacity" : "access denied");
608 		goto clear_assoc;
609 	}
610 
611 	ret = 0;
612 	*short_addr = local->assoc_addr;
613 
614 clear_assoc:
615 	clear_bit(IEEE802154_IS_ASSOCIATING, &local->ongoing);
616 	local->assoc_dev = NULL;
617 
618 	return ret;
619 }
620 
621 int mac802154_process_association_resp(struct ieee802154_sub_if_data *sdata,
622 				       struct sk_buff *skb)
623 {
624 	struct ieee802154_addr *src = &mac_cb(skb)->source;
625 	struct ieee802154_addr *dest = &mac_cb(skb)->dest;
626 	u64 deaddr = swab64((__force u64)dest->extended_addr);
627 	struct ieee802154_local *local = sdata->local;
628 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
629 	struct ieee802154_assoc_resp_pl resp_pl = {};
630 
631 	if (skb->len != sizeof(resp_pl))
632 		return -EINVAL;
633 
634 	if (unlikely(src->mode != IEEE802154_EXTENDED_ADDRESSING ||
635 		     dest->mode != IEEE802154_EXTENDED_ADDRESSING))
636 		return -EINVAL;
637 
638 	if (unlikely(dest->extended_addr != wpan_dev->extended_addr ||
639 		     src->extended_addr != local->assoc_dev->extended_addr))
640 		return -ENODEV;
641 
642 	memcpy(&resp_pl, skb->data, sizeof(resp_pl));
643 	local->assoc_addr = resp_pl.short_addr;
644 	local->assoc_status = resp_pl.status;
645 
646 	dev_dbg(&skb->dev->dev,
647 		"ASSOC RESP 0x%x received from %8phC, getting short address %04x\n",
648 		local->assoc_status, &deaddr, local->assoc_addr);
649 
650 	complete(&local->assoc_done);
651 
652 	return 0;
653 }
654 
655 int mac802154_send_disassociation_notif(struct ieee802154_sub_if_data *sdata,
656 					struct ieee802154_pan_device *target,
657 					u8 reason)
658 {
659 	struct ieee802154_disassociation_notif_frame frame = {};
660 	u64 teaddr = swab64((__force u64)target->extended_addr);
661 	struct ieee802154_local *local = sdata->local;
662 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
663 	struct sk_buff *skb;
664 	int ret;
665 
666 	frame.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
667 	frame.mhr.fc.security_enabled = 0;
668 	frame.mhr.fc.frame_pending = 0;
669 	frame.mhr.fc.ack_request = 1;
670 	frame.mhr.fc.intra_pan = 1;
671 	frame.mhr.fc.dest_addr_mode = (target->mode == IEEE802154_ADDR_LONG) ?
672 		IEEE802154_EXTENDED_ADDRESSING : IEEE802154_SHORT_ADDRESSING;
673 	frame.mhr.fc.version = IEEE802154_2003_STD;
674 	frame.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
675 	frame.mhr.source.mode = IEEE802154_ADDR_LONG;
676 	frame.mhr.source.pan_id = wpan_dev->pan_id;
677 	frame.mhr.source.extended_addr = wpan_dev->extended_addr;
678 	frame.mhr.dest.mode = target->mode;
679 	frame.mhr.dest.pan_id = wpan_dev->pan_id;
680 	if (target->mode == IEEE802154_ADDR_LONG)
681 		frame.mhr.dest.extended_addr = target->extended_addr;
682 	else
683 		frame.mhr.dest.short_addr = target->short_addr;
684 	frame.mhr.seq = atomic_inc_return(&wpan_dev->dsn) & 0xFF;
685 	frame.mac_pl.cmd_id = IEEE802154_CMD_DISASSOCIATION_NOTIFY;
686 	frame.disassoc_pl = reason;
687 
688 	skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ + sizeof(frame.disassoc_pl),
689 			GFP_KERNEL);
690 	if (!skb)
691 		return -ENOBUFS;
692 
693 	skb->dev = sdata->dev;
694 
695 	ret = ieee802154_mac_cmd_push(skb, &frame, &frame.disassoc_pl,
696 				      sizeof(frame.disassoc_pl));
697 	if (ret) {
698 		kfree_skb(skb);
699 		return ret;
700 	}
701 
702 	ret = ieee802154_mlme_tx_one_locked(local, sdata, skb);
703 	if (ret) {
704 		dev_warn(&sdata->dev->dev,
705 			 "No DISASSOC ACK received from %8phC\n", &teaddr);
706 		if (ret > 0)
707 			ret = (ret == IEEE802154_NO_ACK) ? -EREMOTEIO : -EIO;
708 		return ret;
709 	}
710 
711 	dev_dbg(&sdata->dev->dev, "DISASSOC ACK received from %8phC\n", &teaddr);
712 	return 0;
713 }
714 
715 static int
716 mac802154_send_association_resp_locked(struct ieee802154_sub_if_data *sdata,
717 				       struct ieee802154_pan_device *target,
718 				       struct ieee802154_assoc_resp_pl *assoc_resp_pl)
719 {
720 	u64 teaddr = swab64((__force u64)target->extended_addr);
721 	struct ieee802154_association_resp_frame frame = {};
722 	struct ieee802154_local *local = sdata->local;
723 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
724 	struct sk_buff *skb;
725 	int ret;
726 
727 	frame.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
728 	frame.mhr.fc.security_enabled = 0;
729 	frame.mhr.fc.frame_pending = 0;
730 	frame.mhr.fc.ack_request = 1; /* We always expect an ack here */
731 	frame.mhr.fc.intra_pan = 1;
732 	frame.mhr.fc.dest_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
733 	frame.mhr.fc.version = IEEE802154_2003_STD;
734 	frame.mhr.fc.source_addr_mode = IEEE802154_EXTENDED_ADDRESSING;
735 	frame.mhr.source.mode = IEEE802154_ADDR_LONG;
736 	frame.mhr.source.extended_addr = wpan_dev->extended_addr;
737 	frame.mhr.dest.mode = IEEE802154_ADDR_LONG;
738 	frame.mhr.dest.pan_id = wpan_dev->pan_id;
739 	frame.mhr.dest.extended_addr = target->extended_addr;
740 	frame.mhr.seq = atomic_inc_return(&wpan_dev->dsn) & 0xFF;
741 	frame.mac_pl.cmd_id = IEEE802154_CMD_ASSOCIATION_RESP;
742 
743 	skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ + sizeof(*assoc_resp_pl),
744 			GFP_KERNEL);
745 	if (!skb)
746 		return -ENOBUFS;
747 
748 	skb->dev = sdata->dev;
749 
750 	ret = ieee802154_mac_cmd_push(skb, &frame, assoc_resp_pl,
751 				      sizeof(*assoc_resp_pl));
752 	if (ret) {
753 		kfree_skb(skb);
754 		return ret;
755 	}
756 
757 	ret = ieee802154_mlme_tx_locked(local, sdata, skb);
758 	if (ret) {
759 		dev_warn(&sdata->dev->dev,
760 			 "No ASSOC RESP ACK received from %8phC\n", &teaddr);
761 		if (ret > 0)
762 			ret = (ret == IEEE802154_NO_ACK) ? -EREMOTEIO : -EIO;
763 		return ret;
764 	}
765 
766 	return 0;
767 }
768 
769 int mac802154_process_association_req(struct ieee802154_sub_if_data *sdata,
770 				      struct sk_buff *skb)
771 {
772 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
773 	struct ieee802154_addr *src = &mac_cb(skb)->source;
774 	struct ieee802154_addr *dest = &mac_cb(skb)->dest;
775 	struct ieee802154_assoc_resp_pl assoc_resp_pl = {};
776 	struct ieee802154_assoc_req_pl assoc_req_pl;
777 	struct ieee802154_pan_device *child, *exchild;
778 	struct ieee802154_addr tmp = {};
779 	u64 ceaddr;
780 	int ret;
781 
782 	if (skb->len != sizeof(assoc_req_pl))
783 		return -EINVAL;
784 
785 	if (unlikely(src->mode != IEEE802154_EXTENDED_ADDRESSING))
786 		return -EINVAL;
787 
788 	if (unlikely(dest->pan_id != wpan_dev->pan_id))
789 		return -ENODEV;
790 
791 	if (dest->mode == IEEE802154_EXTENDED_ADDRESSING &&
792 	    unlikely(dest->extended_addr != wpan_dev->extended_addr))
793 		return -ENODEV;
794 	else if (dest->mode == IEEE802154_SHORT_ADDRESSING &&
795 		 unlikely(dest->short_addr != wpan_dev->short_addr))
796 		return -ENODEV;
797 
798 	if (wpan_dev->parent) {
799 		dev_dbg(&sdata->dev->dev,
800 			"Ignoring ASSOC REQ, not the PAN coordinator\n");
801 		return -ENODEV;
802 	}
803 
804 	mutex_lock(&wpan_dev->association_lock);
805 
806 	memcpy(&assoc_req_pl, skb->data, sizeof(assoc_req_pl));
807 	if (assoc_req_pl.assoc_type) {
808 		dev_err(&skb->dev->dev, "Fast associations not supported yet\n");
809 		ret = -EOPNOTSUPP;
810 		goto unlock;
811 	}
812 
813 	child = kzalloc_obj(*child);
814 	if (!child) {
815 		ret = -ENOMEM;
816 		goto unlock;
817 	}
818 
819 	child->extended_addr = src->extended_addr;
820 	child->mode = IEEE802154_EXTENDED_ADDRESSING;
821 	ceaddr = swab64((__force u64)child->extended_addr);
822 
823 	if (wpan_dev->nchildren >= wpan_dev->max_associations) {
824 		if (!wpan_dev->max_associations)
825 			assoc_resp_pl.status = IEEE802154_PAN_ACCESS_DENIED;
826 		else
827 			assoc_resp_pl.status = IEEE802154_PAN_AT_CAPACITY;
828 		assoc_resp_pl.short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_BROADCAST);
829 		dev_dbg(&sdata->dev->dev,
830 			"Refusing ASSOC REQ from child %8phC, %s\n", &ceaddr,
831 			assoc_resp_pl.status == IEEE802154_PAN_ACCESS_DENIED ?
832 			"access denied" : "too many children");
833 	} else {
834 		assoc_resp_pl.status = IEEE802154_ASSOCIATION_SUCCESSFUL;
835 		if (assoc_req_pl.alloc_addr) {
836 			assoc_resp_pl.short_addr = cfg802154_get_free_short_addr(wpan_dev);
837 			child->mode = IEEE802154_SHORT_ADDRESSING;
838 		} else {
839 			assoc_resp_pl.short_addr = cpu_to_le16(IEEE802154_ADDR_SHORT_UNSPEC);
840 		}
841 		child->short_addr = assoc_resp_pl.short_addr;
842 		dev_dbg(&sdata->dev->dev,
843 			"Accepting ASSOC REQ from child %8phC, providing short address 0x%04x\n",
844 			&ceaddr, le16_to_cpu(child->short_addr));
845 	}
846 
847 	ret = mac802154_send_association_resp_locked(sdata, child, &assoc_resp_pl);
848 	if (ret || assoc_resp_pl.status != IEEE802154_ASSOCIATION_SUCCESSFUL) {
849 		kfree(child);
850 		goto unlock;
851 	}
852 
853 	dev_dbg(&sdata->dev->dev,
854 		"Successful association with new child %8phC\n", &ceaddr);
855 
856 	/* Ensure this child is not already associated (might happen due to
857 	 * retransmissions), in this case drop the ex structure.
858 	 */
859 	tmp.mode = child->mode;
860 	tmp.extended_addr = child->extended_addr;
861 	exchild = cfg802154_device_is_child(wpan_dev, &tmp);
862 	if (exchild) {
863 		dev_dbg(&sdata->dev->dev,
864 			"Child %8phC was already known\n", &ceaddr);
865 		list_del(&exchild->node);
866 	}
867 
868 	list_add(&child->node, &wpan_dev->children);
869 	wpan_dev->nchildren++;
870 
871 unlock:
872 	mutex_unlock(&wpan_dev->association_lock);
873 	return ret;
874 }
875 
876 int mac802154_process_disassociation_notif(struct ieee802154_sub_if_data *sdata,
877 					   struct sk_buff *skb)
878 {
879 	struct ieee802154_addr *src = &mac_cb(skb)->source;
880 	struct ieee802154_addr *dest = &mac_cb(skb)->dest;
881 	struct wpan_dev *wpan_dev = &sdata->wpan_dev;
882 	struct ieee802154_pan_device *child;
883 	struct ieee802154_addr target;
884 	bool parent;
885 	u64 teaddr;
886 
887 	if (skb->len != sizeof(u8))
888 		return -EINVAL;
889 
890 	if (unlikely(src->mode != IEEE802154_EXTENDED_ADDRESSING))
891 		return -EINVAL;
892 
893 	if (dest->mode == IEEE802154_EXTENDED_ADDRESSING &&
894 	    unlikely(dest->extended_addr != wpan_dev->extended_addr))
895 		return -ENODEV;
896 	else if (dest->mode == IEEE802154_SHORT_ADDRESSING &&
897 		 unlikely(dest->short_addr != wpan_dev->short_addr))
898 		return -ENODEV;
899 
900 	if (dest->pan_id != wpan_dev->pan_id)
901 		return -ENODEV;
902 
903 	target.mode = IEEE802154_EXTENDED_ADDRESSING;
904 	target.extended_addr = src->extended_addr;
905 	teaddr = swab64((__force u64)target.extended_addr);
906 	dev_dbg(&skb->dev->dev, "Processing DISASSOC NOTIF from %8phC\n", &teaddr);
907 
908 	mutex_lock(&wpan_dev->association_lock);
909 	parent = cfg802154_device_is_parent(wpan_dev, &target);
910 	if (!parent)
911 		child = cfg802154_device_is_child(wpan_dev, &target);
912 	if (!parent && !child) {
913 		mutex_unlock(&wpan_dev->association_lock);
914 		return -EINVAL;
915 	}
916 
917 	if (parent) {
918 		kfree(wpan_dev->parent);
919 		wpan_dev->parent = NULL;
920 	} else {
921 		list_del(&child->node);
922 		kfree(child);
923 		wpan_dev->nchildren--;
924 	}
925 
926 	mutex_unlock(&wpan_dev->association_lock);
927 
928 	return 0;
929 }
930