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 */
19static 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 */
50static 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 */
79u32 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 */
150u32 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 */
182void 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 */
227void ieee80211_mps_sta_status_update(struct sta_info *sta)
228{
229	enum nl80211_mesh_power_mode pm;
230	bool do_buffer;
231
232	/*
233	 * use peer-specific power mode if peering is established and the
234	 * peer's power mode is known
235	 */
236	if (sta->plink_state == NL80211_PLINK_ESTAB &&
237	    sta->peer_pm != NL80211_MESH_POWER_UNKNOWN)
238		pm = sta->peer_pm;
239	else
240		pm = sta->nonpeer_pm;
241
242	do_buffer = (pm != NL80211_MESH_POWER_ACTIVE);
243
244	/* Don't let the same PS state be set twice */
245	if (test_sta_flag(sta, WLAN_STA_PS_STA) == do_buffer)
246		return;
247
248	if (do_buffer) {
249		set_sta_flag(sta, WLAN_STA_PS_STA);
250		atomic_inc(&sta->sdata->u.mesh.ps.num_sta_ps);
251		mps_dbg(sta->sdata, "start PS buffering frames towards %pM\n",
252			sta->sta.addr);
253	} else {
254		ieee80211_sta_ps_deliver_wakeup(sta);
255	}
256
257	/* clear the MPSP flags for non-peers or active STA */
258	if (sta->plink_state != NL80211_PLINK_ESTAB) {
259		clear_sta_flag(sta, WLAN_STA_MPSP_OWNER);
260		clear_sta_flag(sta, WLAN_STA_MPSP_RECIPIENT);
261	} else if (!do_buffer) {
262		clear_sta_flag(sta, WLAN_STA_MPSP_OWNER);
263	}
264}
265
266static void mps_set_sta_peer_pm(struct sta_info *sta,
267				struct ieee80211_hdr *hdr)
268{
269	enum nl80211_mesh_power_mode pm;
270	u8 *qc = ieee80211_get_qos_ctl(hdr);
271
272	/*
273	 * Test Power Management field of frame control (PW) and
274	 * mesh power save level subfield of QoS control field (PSL)
275	 *
276	 * | PM | PSL| Mesh PM |
277	 * +----+----+---------+
278	 * | 0  |Rsrv|  Active |
279	 * | 1  | 0  |  Light  |
280	 * | 1  | 1  |  Deep   |
281	 */
282	if (ieee80211_has_pm(hdr->frame_control)) {
283		if (qc[1] & (IEEE80211_QOS_CTL_MESH_PS_LEVEL >> 8))
284			pm = NL80211_MESH_POWER_DEEP_SLEEP;
285		else
286			pm = NL80211_MESH_POWER_LIGHT_SLEEP;
287	} else {
288		pm = NL80211_MESH_POWER_ACTIVE;
289	}
290
291	if (sta->peer_pm == pm)
292		return;
293
294	mps_dbg(sta->sdata, "STA %pM enters mode %d\n",
295		sta->sta.addr, pm);
296
297	sta->peer_pm = pm;
298
299	ieee80211_mps_sta_status_update(sta);
300}
301
302static void mps_set_sta_nonpeer_pm(struct sta_info *sta,
303				   struct ieee80211_hdr *hdr)
304{
305	enum nl80211_mesh_power_mode pm;
306
307	if (ieee80211_has_pm(hdr->frame_control))
308		pm = NL80211_MESH_POWER_DEEP_SLEEP;
309	else
310		pm = NL80211_MESH_POWER_ACTIVE;
311
312	if (sta->nonpeer_pm == pm)
313		return;
314
315	mps_dbg(sta->sdata, "STA %pM sets non-peer mode to %d\n",
316		sta->sta.addr, pm);
317
318	sta->nonpeer_pm = pm;
319
320	ieee80211_mps_sta_status_update(sta);
321}
322
323/**
324 * ieee80211_mps_rx_h_sta_process - frame receive handler for mesh powersave
325 *
326 * @sta: STA info that transmitted the frame
327 * @hdr: IEEE 802.11 (QoS) Header
328 */
329void ieee80211_mps_rx_h_sta_process(struct sta_info *sta,
330				    struct ieee80211_hdr *hdr)
331{
332	if (is_unicast_ether_addr(hdr->addr1) &&
333	    ieee80211_is_data_qos(hdr->frame_control)) {
334		/*
335		 * individually addressed QoS Data/Null frames contain
336		 * peer link-specific PS mode towards the local STA
337		 */
338		mps_set_sta_peer_pm(sta, hdr);
339
340		/* check for mesh Peer Service Period trigger frames */
341		ieee80211_mpsp_trigger_process(ieee80211_get_qos_ctl(hdr),
342					       sta, false, false);
343	} else {
344		/*
345		 * can only determine non-peer PS mode
346		 * (see IEEE802.11-2012 8.2.4.1.7)
347		 */
348		mps_set_sta_nonpeer_pm(sta, hdr);
349	}
350}
351
352
353/* mesh PS frame release */
354
355static void mpsp_trigger_send(struct sta_info *sta, bool rspi, bool eosp)
356{
357	struct ieee80211_sub_if_data *sdata = sta->sdata;
358	struct sk_buff *skb;
359	struct ieee80211_hdr *nullfunc;
360	struct ieee80211_tx_info *info;
361	u8 *qc;
362
363	skb = mps_qos_null_get(sta);
364	if (!skb)
365		return;
366
367	nullfunc = (struct ieee80211_hdr *) skb->data;
368	if (!eosp)
369		nullfunc->frame_control |=
370				cpu_to_le16(IEEE80211_FCTL_MOREDATA);
371	/*
372	 * | RSPI | EOSP |  MPSP triggering   |
373	 * +------+------+--------------------+
374	 * |  0   |  0   | local STA is owner |
375	 * |  0   |  1   | no MPSP (MPSP end) |
376	 * |  1   |  0   | both STA are owner |
377	 * |  1   |  1   | peer STA is owner  | see IEEE802.11-2012 13.14.9.2
378	 */
379	qc = ieee80211_get_qos_ctl(nullfunc);
380	if (rspi)
381		qc[1] |= (IEEE80211_QOS_CTL_RSPI >> 8);
382	if (eosp)
383		qc[0] |= IEEE80211_QOS_CTL_EOSP;
384
385	info = IEEE80211_SKB_CB(skb);
386
387	info->flags |= IEEE80211_TX_CTL_NO_PS_BUFFER |
388		       IEEE80211_TX_CTL_REQ_TX_STATUS;
389
390	mps_dbg(sdata, "sending MPSP trigger%s%s to %pM\n",
391		rspi ? " RSPI" : "", eosp ? " EOSP" : "", sta->sta.addr);
392
393	ieee80211_tx_skb(sdata, skb);
394}
395
396/**
397 * mpsp_qos_null_append - append QoS Null frame to MPSP skb queue if needed
398 *
399 * To properly end a mesh MPSP the last transmitted frame has to set the EOSP
400 * flag in the QoS Control field. In case the current tailing frame is not a
401 * QoS Data frame, append a QoS Null to carry the flag.
402 */
403static void mpsp_qos_null_append(struct sta_info *sta,
404				 struct sk_buff_head *frames)
405{
406	struct ieee80211_sub_if_data *sdata = sta->sdata;
407	struct sk_buff *new_skb, *skb = skb_peek_tail(frames);
408	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
409	struct ieee80211_tx_info *info;
410
411	if (ieee80211_is_data_qos(hdr->frame_control))
412		return;
413
414	new_skb = mps_qos_null_get(sta);
415	if (!new_skb)
416		return;
417
418	mps_dbg(sdata, "appending QoS Null in MPSP towards %pM\n",
419		sta->sta.addr);
420	/*
421	 * This frame has to be transmitted last. Assign lowest priority to
422	 * make sure it cannot pass other frames when releasing multiple ACs.
423	 */
424	new_skb->priority = 1;
425	skb_set_queue_mapping(new_skb, IEEE80211_AC_BK);
426	ieee80211_set_qos_hdr(sdata, new_skb);
427
428	info = IEEE80211_SKB_CB(new_skb);
429	info->control.vif = &sdata->vif;
430	info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING;
431
432	__skb_queue_tail(frames, new_skb);
433}
434
435/**
436 * mps_frame_deliver - transmit frames during mesh powersave
437 *
438 * @sta: STA info to transmit to
439 * @n_frames: number of frames to transmit. -1 for all
440 */
441static void mps_frame_deliver(struct sta_info *sta, int n_frames)
442{
443	struct ieee80211_sub_if_data *sdata = sta->sdata;
444	struct ieee80211_local *local = sdata->local;
445	int ac;
446	struct sk_buff_head frames;
447	struct sk_buff *skb;
448	bool more_data = false;
449
450	skb_queue_head_init(&frames);
451
452	/* collect frame(s) from buffers */
453	for (ac = 0; ac < IEEE80211_NUM_ACS; ac++) {
454		while (n_frames != 0) {
455			skb = skb_dequeue(&sta->tx_filtered[ac]);
456			if (!skb) {
457				skb = skb_dequeue(
458					&sta->ps_tx_buf[ac]);
459				if (skb)
460					local->total_ps_buffered--;
461			}
462			if (!skb)
463				break;
464			n_frames--;
465			__skb_queue_tail(&frames, skb);
466		}
467
468		if (!skb_queue_empty(&sta->tx_filtered[ac]) ||
469		    !skb_queue_empty(&sta->ps_tx_buf[ac]))
470			more_data = true;
471	}
472
473	/* nothing to send? -> EOSP */
474	if (skb_queue_empty(&frames)) {
475		mpsp_trigger_send(sta, false, true);
476		return;
477	}
478
479	/* in a MPSP make sure the last skb is a QoS Data frame */
480	if (test_sta_flag(sta, WLAN_STA_MPSP_OWNER))
481		mpsp_qos_null_append(sta, &frames);
482
483	mps_dbg(sta->sdata, "sending %d frames to PS STA %pM\n",
484		skb_queue_len(&frames), sta->sta.addr);
485
486	/* prepare collected frames for transmission */
487	skb_queue_walk(&frames, skb) {
488		struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
489		struct ieee80211_hdr *hdr = (void *) skb->data;
490
491		/*
492		 * Tell TX path to send this frame even though the
493		 * STA may still remain is PS mode after this frame
494		 * exchange.
495		 */
496		info->flags |= IEEE80211_TX_CTL_NO_PS_BUFFER;
497
498		if (more_data || !skb_queue_is_last(&frames, skb))
499			hdr->frame_control |=
500				cpu_to_le16(IEEE80211_FCTL_MOREDATA);
501		else
502			hdr->frame_control &=
503				cpu_to_le16(~IEEE80211_FCTL_MOREDATA);
504
505		if (skb_queue_is_last(&frames, skb) &&
506		    ieee80211_is_data_qos(hdr->frame_control)) {
507			u8 *qoshdr = ieee80211_get_qos_ctl(hdr);
508
509			/* MPSP trigger frame ends service period */
510			*qoshdr |= IEEE80211_QOS_CTL_EOSP;
511			info->flags |= IEEE80211_TX_CTL_REQ_TX_STATUS;
512		}
513	}
514
515	ieee80211_add_pending_skbs(local, &frames);
516	sta_info_recalc_tim(sta);
517}
518
519/**
520 * ieee80211_mpsp_trigger_process - track status of mesh Peer Service Periods
521 *
522 * @qc: QoS Control field
523 * @sta: peer to start a MPSP with
524 * @tx: frame was transmitted by the local STA
525 * @acked: frame has been transmitted successfully
526 *
527 * NOTE: active mode STA may only serve as MPSP owner
528 */
529void ieee80211_mpsp_trigger_process(u8 *qc, struct sta_info *sta,
530				    bool tx, bool acked)
531{
532	u8 rspi = qc[1] & (IEEE80211_QOS_CTL_RSPI >> 8);
533	u8 eosp = qc[0] & IEEE80211_QOS_CTL_EOSP;
534
535	if (tx) {
536		if (rspi && acked)
537			set_sta_flag(sta, WLAN_STA_MPSP_RECIPIENT);
538
539		if (eosp)
540			clear_sta_flag(sta, WLAN_STA_MPSP_OWNER);
541		else if (acked &&
542			 test_sta_flag(sta, WLAN_STA_PS_STA) &&
543			 !test_and_set_sta_flag(sta, WLAN_STA_MPSP_OWNER))
544			mps_frame_deliver(sta, -1);
545	} else {
546		if (eosp)
547			clear_sta_flag(sta, WLAN_STA_MPSP_RECIPIENT);
548		else if (sta->local_pm != NL80211_MESH_POWER_ACTIVE)
549			set_sta_flag(sta, WLAN_STA_MPSP_RECIPIENT);
550
551		if (rspi && !test_and_set_sta_flag(sta, WLAN_STA_MPSP_OWNER))
552			mps_frame_deliver(sta, -1);
553	}
554}
555
556/**
557 * ieee80211_mps_frame_release - release buffered frames in response to beacon
558 *
559 * @sta: mesh STA
560 * @elems: beacon IEs
561 *
562 * For peers if we have individually-addressed frames buffered or the peer
563 * indicates buffered frames, send a corresponding MPSP trigger frame. Since
564 * we do not evaluate the awake window duration, QoS Nulls are used as MPSP
565 * trigger frames. If the neighbour STA is not a peer, only send single frames.
566 */
567void ieee80211_mps_frame_release(struct sta_info *sta,
568				 struct ieee802_11_elems *elems)
569{
570	int ac, buffer_local = 0;
571	bool has_buffered = false;
572
573	/* TIM map only for LLID <= IEEE80211_MAX_AID */
574	if (sta->plink_state == NL80211_PLINK_ESTAB)
575		has_buffered = ieee80211_check_tim(elems->tim, elems->tim_len,
576				le16_to_cpu(sta->llid) % IEEE80211_MAX_AID);
577
578	if (has_buffered)
579		mps_dbg(sta->sdata, "%pM indicates buffered frames\n",
580			sta->sta.addr);
581
582	/* only transmit to PS STA with announced, non-zero awake window */
583	if (test_sta_flag(sta, WLAN_STA_PS_STA) &&
584	    (!elems->awake_window || !le16_to_cpu(*elems->awake_window)))
585		return;
586
587	for (ac = 0; ac < IEEE80211_NUM_ACS; ac++)
588		buffer_local += skb_queue_len(&sta->ps_tx_buf[ac]) +
589				skb_queue_len(&sta->tx_filtered[ac]);
590
591	if (!has_buffered && !buffer_local)
592		return;
593
594	if (sta->plink_state == NL80211_PLINK_ESTAB)
595		mpsp_trigger_send(sta, has_buffered, !buffer_local);
596	else
597		mps_frame_deliver(sta, 1);
598}
599