xref: /openbmc/linux/net/mac80211/mesh_ps.c (revision ee8a99bd)
1 /*
2  * Copyright 2012-2013, Marco Porsch <marco.porsch@s2005.tu-chemnitz.de>
3  * Copyright 2012-2013, cozybit Inc.
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  */
9 
10 #include "mesh.h"
11 #include "wme.h"
12 
13 
14 /* mesh PS management */
15 
16 /**
17  * mps_qos_null_get - create pre-addressed QoS Null frame for mesh powersave
18  */
19 static struct sk_buff *mps_qos_null_get(struct sta_info *sta)
20 {
21 	struct ieee80211_sub_if_data *sdata = sta->sdata;
22 	struct ieee80211_local *local = sdata->local;
23 	struct ieee80211_hdr *nullfunc; /* use 4addr header */
24 	struct sk_buff *skb;
25 	int size = sizeof(*nullfunc);
26 	__le16 fc;
27 
28 	skb = dev_alloc_skb(local->hw.extra_tx_headroom + size + 2);
29 	if (!skb)
30 		return NULL;
31 	skb_reserve(skb, local->hw.extra_tx_headroom);
32 
33 	nullfunc = (struct ieee80211_hdr *) skb_put(skb, size);
34 	fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_QOS_NULLFUNC);
35 	ieee80211_fill_mesh_addresses(nullfunc, &fc, sta->sta.addr,
36 				      sdata->vif.addr);
37 	nullfunc->frame_control = fc;
38 	nullfunc->duration_id = 0;
39 	/* no address resolution for this frame -> set addr 1 immediately */
40 	memcpy(nullfunc->addr1, sta->sta.addr, ETH_ALEN);
41 	memset(skb_put(skb, 2), 0, 2); /* append QoS control field */
42 	ieee80211_mps_set_frame_flags(sdata, sta, nullfunc);
43 
44 	return skb;
45 }
46 
47 /**
48  * mps_qos_null_tx - send a QoS Null to indicate link-specific power mode
49  */
50 static void mps_qos_null_tx(struct sta_info *sta)
51 {
52 	struct sk_buff *skb;
53 
54 	skb = mps_qos_null_get(sta);
55 	if (!skb)
56 		return;
57 
58 	mps_dbg(sta->sdata, "announcing peer-specific power mode to %pM\n",
59 		sta->sta.addr);
60 
61 	/* don't unintentionally start a MPSP */
62 	if (!test_sta_flag(sta, WLAN_STA_PS_STA)) {
63 		u8 *qc = ieee80211_get_qos_ctl((void *) skb->data);
64 
65 		qc[0] |= IEEE80211_QOS_CTL_EOSP;
66 	}
67 
68 	ieee80211_tx_skb(sta->sdata, skb);
69 }
70 
71 /**
72  * ieee80211_mps_local_status_update - track status of local link-specific PMs
73  *
74  * @sdata: local mesh subif
75  *
76  * sets the non-peer power mode and triggers the driver PS (re-)configuration
77  * Return BSS_CHANGED_BEACON if a beacon update is necessary.
78  */
79 u32 ieee80211_mps_local_status_update(struct ieee80211_sub_if_data *sdata)
80 {
81 	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
82 	struct sta_info *sta;
83 	bool peering = false;
84 	int light_sleep_cnt = 0;
85 	int deep_sleep_cnt = 0;
86 	u32 changed = 0;
87 	enum nl80211_mesh_power_mode nonpeer_pm;
88 
89 	rcu_read_lock();
90 	list_for_each_entry_rcu(sta, &sdata->local->sta_list, list) {
91 		if (sdata != sta->sdata)
92 			continue;
93 
94 		switch (sta->plink_state) {
95 		case NL80211_PLINK_OPN_SNT:
96 		case NL80211_PLINK_OPN_RCVD:
97 		case NL80211_PLINK_CNF_RCVD:
98 			peering = true;
99 			break;
100 		case NL80211_PLINK_ESTAB:
101 			if (sta->local_pm == NL80211_MESH_POWER_LIGHT_SLEEP)
102 				light_sleep_cnt++;
103 			else if (sta->local_pm == NL80211_MESH_POWER_DEEP_SLEEP)
104 				deep_sleep_cnt++;
105 			break;
106 		default:
107 			break;
108 		}
109 	}
110 	rcu_read_unlock();
111 
112 	/*
113 	 * Set non-peer mode to active during peering/scanning/authentication
114 	 * (see IEEE802.11-2012 13.14.8.3). The non-peer mesh power mode is
115 	 * deep sleep if the local STA is in light or deep sleep towards at
116 	 * least one mesh peer (see 13.14.3.1). Otherwise, set it to the
117 	 * user-configured default value.
118 	 */
119 	if (peering) {
120 		mps_dbg(sdata, "setting non-peer PM to active for peering\n");
121 		nonpeer_pm = NL80211_MESH_POWER_ACTIVE;
122 	} else if (light_sleep_cnt || deep_sleep_cnt) {
123 		mps_dbg(sdata, "setting non-peer PM to deep sleep\n");
124 		nonpeer_pm = NL80211_MESH_POWER_DEEP_SLEEP;
125 	} else {
126 		mps_dbg(sdata, "setting non-peer PM to user value\n");
127 		nonpeer_pm = ifmsh->mshcfg.power_mode;
128 	}
129 
130 	/* need update if sleep counts move between 0 and non-zero */
131 	if (ifmsh->nonpeer_pm != nonpeer_pm ||
132 	    !ifmsh->ps_peers_light_sleep != !light_sleep_cnt ||
133 	    !ifmsh->ps_peers_deep_sleep != !deep_sleep_cnt)
134 		changed = BSS_CHANGED_BEACON;
135 
136 	ifmsh->nonpeer_pm = nonpeer_pm;
137 	ifmsh->ps_peers_light_sleep = light_sleep_cnt;
138 	ifmsh->ps_peers_deep_sleep = deep_sleep_cnt;
139 
140 	return changed;
141 }
142 
143 /**
144  * ieee80211_mps_set_sta_local_pm - set local PM towards a mesh STA
145  *
146  * @sta: mesh STA
147  * @pm: the power mode to set
148  * Return BSS_CHANGED_BEACON if a beacon update is in order.
149  */
150 u32 ieee80211_mps_set_sta_local_pm(struct sta_info *sta,
151 				   enum nl80211_mesh_power_mode pm)
152 {
153 	struct ieee80211_sub_if_data *sdata = sta->sdata;
154 
155 	mps_dbg(sdata, "local STA operates in mode %d with %pM\n",
156 		pm, sta->sta.addr);
157 
158 	sta->local_pm = pm;
159 
160 	/*
161 	 * announce peer-specific power mode transition
162 	 * (see IEEE802.11-2012 13.14.3.2 and 13.14.3.3)
163 	 */
164 	if (sta->plink_state == NL80211_PLINK_ESTAB)
165 		mps_qos_null_tx(sta);
166 
167 	return ieee80211_mps_local_status_update(sdata);
168 }
169 
170 /**
171  * ieee80211_mps_set_frame_flags - set mesh PS flags in FC (and QoS Control)
172  *
173  * @sdata: local mesh subif
174  * @sta: mesh STA
175  * @hdr: 802.11 frame header
176  *
177  * see IEEE802.11-2012 8.2.4.1.7 and 8.2.4.5.11
178  *
179  * NOTE: sta must be given when an individually-addressed QoS frame header
180  * is handled, for group-addressed and management frames it is not used
181  */
182 void ieee80211_mps_set_frame_flags(struct ieee80211_sub_if_data *sdata,
183 				   struct sta_info *sta,
184 				   struct ieee80211_hdr *hdr)
185 {
186 	enum nl80211_mesh_power_mode pm;
187 	u8 *qc;
188 
189 	if (WARN_ON(is_unicast_ether_addr(hdr->addr1) &&
190 		    ieee80211_is_data_qos(hdr->frame_control) &&
191 		    !sta))
192 		return;
193 
194 	if (is_unicast_ether_addr(hdr->addr1) &&
195 	    ieee80211_is_data_qos(hdr->frame_control) &&
196 	    sta->plink_state == NL80211_PLINK_ESTAB)
197 		pm = sta->local_pm;
198 	else
199 		pm = sdata->u.mesh.nonpeer_pm;
200 
201 	if (pm == NL80211_MESH_POWER_ACTIVE)
202 		hdr->frame_control &= cpu_to_le16(~IEEE80211_FCTL_PM);
203 	else
204 		hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PM);
205 
206 	if (!ieee80211_is_data_qos(hdr->frame_control))
207 		return;
208 
209 	qc = ieee80211_get_qos_ctl(hdr);
210 
211 	if ((is_unicast_ether_addr(hdr->addr1) &&
212 	     pm == NL80211_MESH_POWER_DEEP_SLEEP) ||
213 	    (is_multicast_ether_addr(hdr->addr1) &&
214 	     sdata->u.mesh.ps_peers_deep_sleep > 0))
215 		qc[1] |= (IEEE80211_QOS_CTL_MESH_PS_LEVEL >> 8);
216 	else
217 		qc[1] &= ~(IEEE80211_QOS_CTL_MESH_PS_LEVEL >> 8);
218 }
219 
220 /**
221  * ieee80211_mps_sta_status_update - update buffering status of neighbor STA
222  *
223  * @sta: mesh STA
224  *
225  * called after change of peering status or non-peer/peer-specific power mode
226  */
227 void ieee80211_mps_sta_status_update(struct sta_info *sta)
228 {
229 	enum nl80211_mesh_power_mode pm;
230 	bool do_buffer;
231 
232 	/* For non-assoc STA, prevent buffering or frame transmission */
233 	if (sta->sta_state < IEEE80211_STA_ASSOC)
234 		return;
235 
236 	/*
237 	 * use peer-specific power mode if peering is established and the
238 	 * peer's power mode is known
239 	 */
240 	if (sta->plink_state == NL80211_PLINK_ESTAB &&
241 	    sta->peer_pm != NL80211_MESH_POWER_UNKNOWN)
242 		pm = sta->peer_pm;
243 	else
244 		pm = sta->nonpeer_pm;
245 
246 	do_buffer = (pm != NL80211_MESH_POWER_ACTIVE);
247 
248 	/* Don't let the same PS state be set twice */
249 	if (test_sta_flag(sta, WLAN_STA_PS_STA) == do_buffer)
250 		return;
251 
252 	if (do_buffer) {
253 		set_sta_flag(sta, WLAN_STA_PS_STA);
254 		atomic_inc(&sta->sdata->u.mesh.ps.num_sta_ps);
255 		mps_dbg(sta->sdata, "start PS buffering frames towards %pM\n",
256 			sta->sta.addr);
257 	} else {
258 		ieee80211_sta_ps_deliver_wakeup(sta);
259 	}
260 
261 	/* clear the MPSP flags for non-peers or active STA */
262 	if (sta->plink_state != NL80211_PLINK_ESTAB) {
263 		clear_sta_flag(sta, WLAN_STA_MPSP_OWNER);
264 		clear_sta_flag(sta, WLAN_STA_MPSP_RECIPIENT);
265 	} else if (!do_buffer) {
266 		clear_sta_flag(sta, WLAN_STA_MPSP_OWNER);
267 	}
268 }
269 
270 static void mps_set_sta_peer_pm(struct sta_info *sta,
271 				struct ieee80211_hdr *hdr)
272 {
273 	enum nl80211_mesh_power_mode pm;
274 	u8 *qc = ieee80211_get_qos_ctl(hdr);
275 
276 	/*
277 	 * Test Power Management field of frame control (PW) and
278 	 * mesh power save level subfield of QoS control field (PSL)
279 	 *
280 	 * | PM | PSL| Mesh PM |
281 	 * +----+----+---------+
282 	 * | 0  |Rsrv|  Active |
283 	 * | 1  | 0  |  Light  |
284 	 * | 1  | 1  |  Deep   |
285 	 */
286 	if (ieee80211_has_pm(hdr->frame_control)) {
287 		if (qc[1] & (IEEE80211_QOS_CTL_MESH_PS_LEVEL >> 8))
288 			pm = NL80211_MESH_POWER_DEEP_SLEEP;
289 		else
290 			pm = NL80211_MESH_POWER_LIGHT_SLEEP;
291 	} else {
292 		pm = NL80211_MESH_POWER_ACTIVE;
293 	}
294 
295 	if (sta->peer_pm == pm)
296 		return;
297 
298 	mps_dbg(sta->sdata, "STA %pM enters mode %d\n",
299 		sta->sta.addr, pm);
300 
301 	sta->peer_pm = pm;
302 
303 	ieee80211_mps_sta_status_update(sta);
304 }
305 
306 static void mps_set_sta_nonpeer_pm(struct sta_info *sta,
307 				   struct ieee80211_hdr *hdr)
308 {
309 	enum nl80211_mesh_power_mode pm;
310 
311 	if (ieee80211_has_pm(hdr->frame_control))
312 		pm = NL80211_MESH_POWER_DEEP_SLEEP;
313 	else
314 		pm = NL80211_MESH_POWER_ACTIVE;
315 
316 	if (sta->nonpeer_pm == pm)
317 		return;
318 
319 	mps_dbg(sta->sdata, "STA %pM sets non-peer mode to %d\n",
320 		sta->sta.addr, pm);
321 
322 	sta->nonpeer_pm = pm;
323 
324 	ieee80211_mps_sta_status_update(sta);
325 }
326 
327 /**
328  * ieee80211_mps_rx_h_sta_process - frame receive handler for mesh powersave
329  *
330  * @sta: STA info that transmitted the frame
331  * @hdr: IEEE 802.11 (QoS) Header
332  */
333 void ieee80211_mps_rx_h_sta_process(struct sta_info *sta,
334 				    struct ieee80211_hdr *hdr)
335 {
336 	if (is_unicast_ether_addr(hdr->addr1) &&
337 	    ieee80211_is_data_qos(hdr->frame_control)) {
338 		/*
339 		 * individually addressed QoS Data/Null frames contain
340 		 * peer link-specific PS mode towards the local STA
341 		 */
342 		mps_set_sta_peer_pm(sta, hdr);
343 
344 		/* check for mesh Peer Service Period trigger frames */
345 		ieee80211_mpsp_trigger_process(ieee80211_get_qos_ctl(hdr),
346 					       sta, false, false);
347 	} else {
348 		/*
349 		 * can only determine non-peer PS mode
350 		 * (see IEEE802.11-2012 8.2.4.1.7)
351 		 */
352 		mps_set_sta_nonpeer_pm(sta, hdr);
353 	}
354 }
355 
356 
357 /* mesh PS frame release */
358 
359 static void mpsp_trigger_send(struct sta_info *sta, bool rspi, bool eosp)
360 {
361 	struct ieee80211_sub_if_data *sdata = sta->sdata;
362 	struct sk_buff *skb;
363 	struct ieee80211_hdr *nullfunc;
364 	struct ieee80211_tx_info *info;
365 	u8 *qc;
366 
367 	skb = mps_qos_null_get(sta);
368 	if (!skb)
369 		return;
370 
371 	nullfunc = (struct ieee80211_hdr *) skb->data;
372 	if (!eosp)
373 		nullfunc->frame_control |=
374 				cpu_to_le16(IEEE80211_FCTL_MOREDATA);
375 	/*
376 	 * | RSPI | EOSP |  MPSP triggering   |
377 	 * +------+------+--------------------+
378 	 * |  0   |  0   | local STA is owner |
379 	 * |  0   |  1   | no MPSP (MPSP end) |
380 	 * |  1   |  0   | both STA are owner |
381 	 * |  1   |  1   | peer STA is owner  | see IEEE802.11-2012 13.14.9.2
382 	 */
383 	qc = ieee80211_get_qos_ctl(nullfunc);
384 	if (rspi)
385 		qc[1] |= (IEEE80211_QOS_CTL_RSPI >> 8);
386 	if (eosp)
387 		qc[0] |= IEEE80211_QOS_CTL_EOSP;
388 
389 	info = IEEE80211_SKB_CB(skb);
390 
391 	info->flags |= IEEE80211_TX_CTL_NO_PS_BUFFER |
392 		       IEEE80211_TX_CTL_REQ_TX_STATUS;
393 
394 	mps_dbg(sdata, "sending MPSP trigger%s%s to %pM\n",
395 		rspi ? " RSPI" : "", eosp ? " EOSP" : "", sta->sta.addr);
396 
397 	ieee80211_tx_skb(sdata, skb);
398 }
399 
400 /**
401  * mpsp_qos_null_append - append QoS Null frame to MPSP skb queue if needed
402  *
403  * To properly end a mesh MPSP the last transmitted frame has to set the EOSP
404  * flag in the QoS Control field. In case the current tailing frame is not a
405  * QoS Data frame, append a QoS Null to carry the flag.
406  */
407 static void mpsp_qos_null_append(struct sta_info *sta,
408 				 struct sk_buff_head *frames)
409 {
410 	struct ieee80211_sub_if_data *sdata = sta->sdata;
411 	struct sk_buff *new_skb, *skb = skb_peek_tail(frames);
412 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
413 	struct ieee80211_tx_info *info;
414 
415 	if (ieee80211_is_data_qos(hdr->frame_control))
416 		return;
417 
418 	new_skb = mps_qos_null_get(sta);
419 	if (!new_skb)
420 		return;
421 
422 	mps_dbg(sdata, "appending QoS Null in MPSP towards %pM\n",
423 		sta->sta.addr);
424 	/*
425 	 * This frame has to be transmitted last. Assign lowest priority to
426 	 * make sure it cannot pass other frames when releasing multiple ACs.
427 	 */
428 	new_skb->priority = 1;
429 	skb_set_queue_mapping(new_skb, IEEE80211_AC_BK);
430 	ieee80211_set_qos_hdr(sdata, new_skb);
431 
432 	info = IEEE80211_SKB_CB(new_skb);
433 	info->control.vif = &sdata->vif;
434 	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
435 
436 	__skb_queue_tail(frames, new_skb);
437 }
438 
439 /**
440  * mps_frame_deliver - transmit frames during mesh powersave
441  *
442  * @sta: STA info to transmit to
443  * @n_frames: number of frames to transmit. -1 for all
444  */
445 static void mps_frame_deliver(struct sta_info *sta, int n_frames)
446 {
447 	struct ieee80211_sub_if_data *sdata = sta->sdata;
448 	struct ieee80211_local *local = sdata->local;
449 	int ac;
450 	struct sk_buff_head frames;
451 	struct sk_buff *skb;
452 	bool more_data = false;
453 
454 	skb_queue_head_init(&frames);
455 
456 	/* collect frame(s) from buffers */
457 	for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
458 		while (n_frames != 0) {
459 			skb = skb_dequeue(&sta->tx_filtered[ac]);
460 			if (!skb) {
461 				skb = skb_dequeue(
462 					&sta->ps_tx_buf[ac]);
463 				if (skb)
464 					local->total_ps_buffered--;
465 			}
466 			if (!skb)
467 				break;
468 			n_frames--;
469 			__skb_queue_tail(&frames, skb);
470 		}
471 
472 		if (!skb_queue_empty(&sta->tx_filtered[ac]) ||
473 		    !skb_queue_empty(&sta->ps_tx_buf[ac]))
474 			more_data = true;
475 	}
476 
477 	/* nothing to send? -> EOSP */
478 	if (skb_queue_empty(&frames)) {
479 		mpsp_trigger_send(sta, false, true);
480 		return;
481 	}
482 
483 	/* in a MPSP make sure the last skb is a QoS Data frame */
484 	if (test_sta_flag(sta, WLAN_STA_MPSP_OWNER))
485 		mpsp_qos_null_append(sta, &frames);
486 
487 	mps_dbg(sta->sdata, "sending %d frames to PS STA %pM\n",
488 		skb_queue_len(&frames), sta->sta.addr);
489 
490 	/* prepare collected frames for transmission */
491 	skb_queue_walk(&frames, skb) {
492 		struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
493 		struct ieee80211_hdr *hdr = (void *) skb->data;
494 
495 		/*
496 		 * Tell TX path to send this frame even though the
497 		 * STA may still remain is PS mode after this frame
498 		 * exchange.
499 		 */
500 		info->flags |= IEEE80211_TX_CTL_NO_PS_BUFFER;
501 
502 		if (more_data || !skb_queue_is_last(&frames, skb))
503 			hdr->frame_control |=
504 				cpu_to_le16(IEEE80211_FCTL_MOREDATA);
505 		else
506 			hdr->frame_control &=
507 				cpu_to_le16(~IEEE80211_FCTL_MOREDATA);
508 
509 		if (skb_queue_is_last(&frames, skb) &&
510 		    ieee80211_is_data_qos(hdr->frame_control)) {
511 			u8 *qoshdr = ieee80211_get_qos_ctl(hdr);
512 
513 			/* MPSP trigger frame ends service period */
514 			*qoshdr |= IEEE80211_QOS_CTL_EOSP;
515 			info->flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
516 		}
517 	}
518 
519 	ieee80211_add_pending_skbs(local, &frames);
520 	sta_info_recalc_tim(sta);
521 }
522 
523 /**
524  * ieee80211_mpsp_trigger_process - track status of mesh Peer Service Periods
525  *
526  * @qc: QoS Control field
527  * @sta: peer to start a MPSP with
528  * @tx: frame was transmitted by the local STA
529  * @acked: frame has been transmitted successfully
530  *
531  * NOTE: active mode STA may only serve as MPSP owner
532  */
533 void ieee80211_mpsp_trigger_process(u8 *qc, struct sta_info *sta,
534 				    bool tx, bool acked)
535 {
536 	u8 rspi = qc[1] & (IEEE80211_QOS_CTL_RSPI >> 8);
537 	u8 eosp = qc[0] & IEEE80211_QOS_CTL_EOSP;
538 
539 	if (tx) {
540 		if (rspi && acked)
541 			set_sta_flag(sta, WLAN_STA_MPSP_RECIPIENT);
542 
543 		if (eosp)
544 			clear_sta_flag(sta, WLAN_STA_MPSP_OWNER);
545 		else if (acked &&
546 			 test_sta_flag(sta, WLAN_STA_PS_STA) &&
547 			 !test_and_set_sta_flag(sta, WLAN_STA_MPSP_OWNER))
548 			mps_frame_deliver(sta, -1);
549 	} else {
550 		if (eosp)
551 			clear_sta_flag(sta, WLAN_STA_MPSP_RECIPIENT);
552 		else if (sta->local_pm != NL80211_MESH_POWER_ACTIVE)
553 			set_sta_flag(sta, WLAN_STA_MPSP_RECIPIENT);
554 
555 		if (rspi && !test_and_set_sta_flag(sta, WLAN_STA_MPSP_OWNER))
556 			mps_frame_deliver(sta, -1);
557 	}
558 }
559 
560 /**
561  * ieee80211_mps_frame_release - release buffered frames in response to beacon
562  *
563  * @sta: mesh STA
564  * @elems: beacon IEs
565  *
566  * For peers if we have individually-addressed frames buffered or the peer
567  * indicates buffered frames, send a corresponding MPSP trigger frame. Since
568  * we do not evaluate the awake window duration, QoS Nulls are used as MPSP
569  * trigger frames. If the neighbour STA is not a peer, only send single frames.
570  */
571 void ieee80211_mps_frame_release(struct sta_info *sta,
572 				 struct ieee802_11_elems *elems)
573 {
574 	int ac, buffer_local = 0;
575 	bool has_buffered = false;
576 
577 	/* TIM map only for LLID <= IEEE80211_MAX_AID */
578 	if (sta->plink_state == NL80211_PLINK_ESTAB)
579 		has_buffered = ieee80211_check_tim(elems->tim, elems->tim_len,
580 				le16_to_cpu(sta->llid) % IEEE80211_MAX_AID);
581 
582 	if (has_buffered)
583 		mps_dbg(sta->sdata, "%pM indicates buffered frames\n",
584 			sta->sta.addr);
585 
586 	/* only transmit to PS STA with announced, non-zero awake window */
587 	if (test_sta_flag(sta, WLAN_STA_PS_STA) &&
588 	    (!elems->awake_window || !le16_to_cpu(*elems->awake_window)))
589 		return;
590 
591 	for (ac = 0; ac < IEEE80211_NUM_ACS; ac++)
592 		buffer_local += skb_queue_len(&sta->ps_tx_buf[ac]) +
593 				skb_queue_len(&sta->tx_filtered[ac]);
594 
595 	if (!has_buffered && !buffer_local)
596 		return;
597 
598 	if (sta->plink_state == NL80211_PLINK_ESTAB)
599 		mpsp_trigger_send(sta, has_buffered, !buffer_local);
600 	else
601 		mps_frame_deliver(sta, 1);
602 }
603