dynack.c

  1/*
  2 * Copyright (c) 2014, Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
  3 *
  4 * Permission to use, copy, modify, and/or distribute this software for any
  5 * purpose with or without fee is hereby granted, provided that the above
  6 * copyright notice and this permission notice appear in all copies.
  7 *
  8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 15 */
 16
 17#include <linux/export.h>
 18#include "ath9k.h"
 19#include "hw.h"
 20#include "dynack.h"
 21
 22#define COMPUTE_TO		(5 * HZ)
 23#define LATEACK_DELAY		(10 * HZ)
 24#define EWMA_LEVEL		96
 25#define EWMA_DIV		128
 26
 27/**
 28 * ath_dynack_get_max_to - set max timeout according to channel width
 29 * @ah: ath hw
 30 *
 31 */
 32static u32 ath_dynack_get_max_to(struct ath_hw *ah)
 33{
 34	const struct ath9k_channel *chan = ah->curchan;
 35
 36	if (!chan)
 37		return 300;
 38
 39	if (IS_CHAN_HT40(chan))
 40		return 300;
 41	if (IS_CHAN_HALF_RATE(chan))
 42		return 750;
 43	if (IS_CHAN_QUARTER_RATE(chan))
 44		return 1500;
 45	return 600;
 46}
 47
 48/*
 49 * ath_dynack_ewma - EWMA (Exponentially Weighted Moving Average) calculation
 50 */
 51static inline int ath_dynack_ewma(int old, int new)
 52{
 53	if (old > 0)
 54		return (new * (EWMA_DIV - EWMA_LEVEL) +
 55			old * EWMA_LEVEL) / EWMA_DIV;
 56	else
 57		return new;
 58}
 59
 60/**
 61 * ath_dynack_get_sifs - get sifs time based on phy used
 62 * @ah: ath hw
 63 * @phy: phy used
 64 *
 65 */
 66static inline u32 ath_dynack_get_sifs(struct ath_hw *ah, int phy)
 67{
 68	u32 sifs = CCK_SIFS_TIME;
 69
 70	if (phy == WLAN_RC_PHY_OFDM) {
 71		if (IS_CHAN_QUARTER_RATE(ah->curchan))
 72			sifs = OFDM_SIFS_TIME_QUARTER;
 73		else if (IS_CHAN_HALF_RATE(ah->curchan))
 74			sifs = OFDM_SIFS_TIME_HALF;
 75		else
 76			sifs = OFDM_SIFS_TIME;
 77	}
 78	return sifs;
 79}
 80
 81/**
 82 * ath_dynack_bssidmask - filter out ACK frames based on BSSID mask
 83 * @ah: ath hw
 84 * @mac: receiver address
 85 */
 86static inline bool ath_dynack_bssidmask(struct ath_hw *ah, const u8 *mac)
 87{
 88	int i;
 89	struct ath_common *common = ath9k_hw_common(ah);
 90
 91	for (i = 0; i < ETH_ALEN; i++) {
 92		if ((common->macaddr[i] & common->bssidmask[i]) !=
 93		    (mac[i] & common->bssidmask[i]))
 94			return false;
 95	}
 96
 97	return true;
 98}
 99
100/**
101 * ath_dynack_set_timeout - configure timeouts/slottime registers
102 * @ah: ath hw
103 * @to: timeout value
104 *
105 */
106static void ath_dynack_set_timeout(struct ath_hw *ah, int to)
107{
108	struct ath_common *common = ath9k_hw_common(ah);
109	int slottime = (to - 3) / 2;
110
111	ath_dbg(common, DYNACK, "ACK timeout %u slottime %u\n",
112		to, slottime);
113	ath9k_hw_setslottime(ah, slottime);
114	ath9k_hw_set_ack_timeout(ah, to);
115	ath9k_hw_set_cts_timeout(ah, to);
116}
117
118/**
119 * ath_dynack_compute_ackto - compute ACK timeout as the maximum STA timeout
120 * @ah: ath hw
121 *
122 * should be called while holding qlock
123 */
124static void ath_dynack_compute_ackto(struct ath_hw *ah)
125{
126	struct ath_dynack *da = &ah->dynack;
127	struct ath_node *an;
128	int to = 0;
129
130	list_for_each_entry(an, &da->nodes, list)
131		if (an->ackto > to)
132			to = an->ackto;
133
134	if (to && da->ackto != to) {
135		ath_dynack_set_timeout(ah, to);
136		da->ackto = to;
137	}
138}
139
140/**
141 * ath_dynack_compute_to - compute STA ACK timeout
142 * @ah: ath hw
143 *
144 * should be called while holding qlock
145 */
146static void ath_dynack_compute_to(struct ath_hw *ah)
147{
148	struct ath_dynack *da = &ah->dynack;
149	u32 ackto, ack_ts, max_to;
150	struct ieee80211_sta *sta;
151	struct ts_info *st_ts;
152	struct ath_node *an;
153	u8 *dst, *src;
154
155	rcu_read_lock();
156
157	max_to = ath_dynack_get_max_to(ah);
158	while (da->st_rbf.h_rb != da->st_rbf.t_rb &&
159	       da->ack_rbf.h_rb != da->ack_rbf.t_rb) {
160		ack_ts = da->ack_rbf.tstamp[da->ack_rbf.h_rb];
161		st_ts = &da->st_rbf.ts[da->st_rbf.h_rb];
162		dst = da->st_rbf.addr[da->st_rbf.h_rb].h_dest;
163		src = da->st_rbf.addr[da->st_rbf.h_rb].h_src;
164
165		ath_dbg(ath9k_hw_common(ah), DYNACK,
166			"ack_ts %u st_ts %u st_dur %u [%u-%u]\n",
167			ack_ts, st_ts->tstamp, st_ts->dur,
168			da->ack_rbf.h_rb, da->st_rbf.h_rb);
169
170		if (ack_ts > st_ts->tstamp + st_ts->dur) {
171			ackto = ack_ts - st_ts->tstamp - st_ts->dur;
172
173			if (ackto < max_to) {
174				sta = ieee80211_find_sta_by_ifaddr(ah->hw, dst,
175								   src);
176				if (sta) {
177					an = (struct ath_node *)sta->drv_priv;
178					an->ackto = ath_dynack_ewma(an->ackto,
179								    ackto);
180					ath_dbg(ath9k_hw_common(ah), DYNACK,
181						"%pM to %d [%u]\n", dst,
182						an->ackto, ackto);
183					if (time_is_before_jiffies(da->lto)) {
184						ath_dynack_compute_ackto(ah);
185						da->lto = jiffies + COMPUTE_TO;
186					}
187				}
188				INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
189			}
190			INCR(da->st_rbf.h_rb, ATH_DYN_BUF);
191		} else {
192			INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
193		}
194	}
195
196	rcu_read_unlock();
197}
198
199/**
200 * ath_dynack_sample_tx_ts - status timestamp sampling method
201 * @ah: ath hw
202 * @skb: socket buffer
203 * @ts: tx status info
204 * @sta: station pointer
205 *
206 */
207void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
208			     struct ath_tx_status *ts,
209			     struct ieee80211_sta *sta)
210{
211	struct ieee80211_hdr *hdr;
212	struct ath_dynack *da = &ah->dynack;
213	struct ath_common *common = ath9k_hw_common(ah);
214	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
215	u32 dur = ts->duration;
216	u8 ridx;
217
218	if (!da->enabled || (info->flags & IEEE80211_TX_CTL_NO_ACK))
219		return;
220
221	spin_lock_bh(&da->qlock);
222
223	hdr = (struct ieee80211_hdr *)skb->data;
224
225	/* late ACK */
226	if (ts->ts_status & ATH9K_TXERR_XRETRY) {
227		if (ieee80211_is_assoc_req(hdr->frame_control) ||
228		    ieee80211_is_assoc_resp(hdr->frame_control) ||
229		    ieee80211_is_auth(hdr->frame_control)) {
230			u32 max_to = ath_dynack_get_max_to(ah);
231
232			ath_dbg(common, DYNACK, "late ack\n");
233			ath_dynack_set_timeout(ah, max_to);
234			if (sta) {
235				struct ath_node *an;
236
237				an = (struct ath_node *)sta->drv_priv;
238				an->ackto = -1;
239			}
240			da->lto = jiffies + LATEACK_DELAY;
241		}
242
243		spin_unlock_bh(&da->qlock);
244		return;
245	}
246
247	ridx = ts->ts_rateindex;
248
249	da->st_rbf.ts[da->st_rbf.t_rb].tstamp = ts->ts_tstamp;
250
251	/* ether_addr_copy() gives a false warning on gcc-10 so use memcpy()
252	 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97490
253	 */
254	memcpy(da->st_rbf.addr[da->st_rbf.t_rb].h_dest, hdr->addr1, ETH_ALEN);
255	memcpy(da->st_rbf.addr[da->st_rbf.t_rb].h_src, hdr->addr2, ETH_ALEN);
256
257	if (!(info->status.rates[ridx].flags & IEEE80211_TX_RC_MCS)) {
258		const struct ieee80211_rate *rate;
259		struct ieee80211_tx_rate *rates = info->status.rates;
260		u32 phy;
261
262		rate = &common->sbands[info->band].bitrates[rates[ridx].idx];
263		if (info->band == NL80211_BAND_2GHZ &&
264		    !(rate->flags & IEEE80211_RATE_ERP_G))
265			phy = WLAN_RC_PHY_CCK;
266		else
267			phy = WLAN_RC_PHY_OFDM;
268
269		dur -= ath_dynack_get_sifs(ah, phy);
270	}
271	da->st_rbf.ts[da->st_rbf.t_rb].dur = dur;
272
273	INCR(da->st_rbf.t_rb, ATH_DYN_BUF);
274	if (da->st_rbf.t_rb == da->st_rbf.h_rb)
275		INCR(da->st_rbf.h_rb, ATH_DYN_BUF);
276
277	ath_dbg(common, DYNACK, "{%pM} tx sample %u [dur %u][h %u-t %u]\n",
278		hdr->addr1, ts->ts_tstamp, dur, da->st_rbf.h_rb,
279		da->st_rbf.t_rb);
280
281	ath_dynack_compute_to(ah);
282
283	spin_unlock_bh(&da->qlock);
284}
285EXPORT_SYMBOL(ath_dynack_sample_tx_ts);
286
287/**
288 * ath_dynack_sample_ack_ts - ACK timestamp sampling method
289 * @ah: ath hw
290 * @skb: socket buffer
291 * @ts: rx timestamp
292 *
293 */
294void ath_dynack_sample_ack_ts(struct ath_hw *ah, struct sk_buff *skb,
295			      u32 ts)
296{
297	struct ath_dynack *da = &ah->dynack;
298	struct ath_common *common = ath9k_hw_common(ah);
299	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
300
301	if (!da->enabled || !ath_dynack_bssidmask(ah, hdr->addr1))
302		return;
303
304	spin_lock_bh(&da->qlock);
305	da->ack_rbf.tstamp[da->ack_rbf.t_rb] = ts;
306
307	INCR(da->ack_rbf.t_rb, ATH_DYN_BUF);
308	if (da->ack_rbf.t_rb == da->ack_rbf.h_rb)
309		INCR(da->ack_rbf.h_rb, ATH_DYN_BUF);
310
311	ath_dbg(common, DYNACK, "rx sample %u [h %u-t %u]\n",
312		ts, da->ack_rbf.h_rb, da->ack_rbf.t_rb);
313
314	ath_dynack_compute_to(ah);
315
316	spin_unlock_bh(&da->qlock);
317}
318EXPORT_SYMBOL(ath_dynack_sample_ack_ts);
319
320/**
321 * ath_dynack_node_init - init ath_node related info
322 * @ah: ath hw
323 * @an: ath node
324 *
325 */
326void ath_dynack_node_init(struct ath_hw *ah, struct ath_node *an)
327{
328	struct ath_dynack *da = &ah->dynack;
329
330	an->ackto = da->ackto;
331
332	spin_lock_bh(&da->qlock);
333	list_add_tail(&an->list, &da->nodes);
334	spin_unlock_bh(&da->qlock);
335}
336EXPORT_SYMBOL(ath_dynack_node_init);
337
338/**
339 * ath_dynack_node_deinit - deinit ath_node related info
340 * @ah: ath hw
341 * @an: ath node
342 *
343 */
344void ath_dynack_node_deinit(struct ath_hw *ah, struct ath_node *an)
345{
346	struct ath_dynack *da = &ah->dynack;
347
348	spin_lock_bh(&da->qlock);
349	list_del(&an->list);
350	spin_unlock_bh(&da->qlock);
351}
352EXPORT_SYMBOL(ath_dynack_node_deinit);
353
354/**
355 * ath_dynack_reset - reset dynack processing
356 * @ah: ath hw
357 *
358 */
359void ath_dynack_reset(struct ath_hw *ah)
360{
361	struct ath_dynack *da = &ah->dynack;
362	struct ath_node *an;
363
364	spin_lock_bh(&da->qlock);
365
366	da->lto = jiffies + COMPUTE_TO;
367
368	da->st_rbf.t_rb = 0;
369	da->st_rbf.h_rb = 0;
370	da->ack_rbf.t_rb = 0;
371	da->ack_rbf.h_rb = 0;
372
373	da->ackto = ath_dynack_get_max_to(ah);
374	list_for_each_entry(an, &da->nodes, list)
375		an->ackto = da->ackto;
376
377	/* init acktimeout */
378	ath_dynack_set_timeout(ah, da->ackto);
379
380	spin_unlock_bh(&da->qlock);
381}
382EXPORT_SYMBOL(ath_dynack_reset);
383
384/**
385 * ath_dynack_init - init dynack data structure
386 * @ah: ath hw
387 *
388 */
389void ath_dynack_init(struct ath_hw *ah)
390{
391	struct ath_dynack *da = &ah->dynack;
392
393	memset(da, 0, sizeof(struct ath_dynack));
394
395	spin_lock_init(&da->qlock);
396	INIT_LIST_HEAD(&da->nodes);
397	/* ackto = slottime + sifs + air delay */
398	da->ackto = 9 + 16 + 64;
399
400	ah->hw->wiphy->features |= NL80211_FEATURE_ACKTO_ESTIMATION;
401}