xref: /freebsd/sys/dev/ath/ath_rate/onoe/onoe.c (revision 7750ad47a9a7dbc83f87158464170c8640723293)
1 /*-
2  * Copyright (c) 2002-2007 Sam Leffler, Errno Consulting
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer,
10  *    without modification.
11  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
12  *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
13  *    redistribution must be conditioned upon including a substantially
14  *    similar Disclaimer requirement for further binary redistribution.
15  *
16  * NO WARRANTY
17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19  * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
20  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
21  * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
22  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
25  * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
27  * THE POSSIBILITY OF SUCH DAMAGES.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 /*
34  * Atsushi Onoe's rate control algorithm.
35  */
36 #include "opt_inet.h"
37 #include "opt_wlan.h"
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/sysctl.h>
42 #include <sys/kernel.h>
43 #include <sys/lock.h>
44 #include <sys/mutex.h>
45 #include <sys/errno.h>
46 
47 #include <machine/bus.h>
48 #include <machine/resource.h>
49 #include <sys/bus.h>
50 
51 #include <sys/socket.h>
52 
53 #include <net/if.h>
54 #include <net/if_media.h>
55 #include <net/if_arp.h>
56 #include <net/ethernet.h>		/* XXX for ether_sprintf */
57 
58 #include <net80211/ieee80211_var.h>
59 
60 #include <net/bpf.h>
61 
62 #ifdef INET
63 #include <netinet/in.h>
64 #include <netinet/if_ether.h>
65 #endif
66 
67 #include <dev/ath/if_athvar.h>
68 #include <dev/ath/ath_rate/onoe/onoe.h>
69 #include <dev/ath/ath_hal/ah_desc.h>
70 
71 /*
72  * Default parameters for the rate control algorithm.  These are
73  * all tunable with sysctls.  The rate controller runs periodically
74  * (each ath_rateinterval ms) analyzing transmit statistics for each
75  * neighbor/station (when operating in station mode this is only the AP).
76  * If transmits look to be working well over a sampling period then
77  * it gives a "raise rate credit".  If transmits look to not be working
78  * well than it deducts a credit.  If the credits cross a threshold then
79  * the transmit rate is raised.  Various error conditions force the
80  * the transmit rate to be dropped.
81  *
82  * The decision to issue/deduct a credit is based on the errors and
83  * retries accumulated over the sampling period.  ath_rate_raise defines
84  * the percent of retransmits for which a credit is issued/deducted.
85  * ath_rate_raise_threshold defines the threshold on credits at which
86  * the transmit rate is increased.
87  *
88  * XXX this algorithm is flawed.
89  */
90 static	int ath_rateinterval = 1000;		/* rate ctl interval (ms)  */
91 static	int ath_rate_raise = 10;		/* add credit threshold */
92 static	int ath_rate_raise_threshold = 10;	/* rate ctl raise threshold */
93 
94 static void	ath_rate_update(struct ath_softc *, struct ieee80211_node *,
95 			int rate);
96 static void	ath_rate_ctl_start(struct ath_softc *, struct ieee80211_node *);
97 static void	ath_rate_ctl(void *, struct ieee80211_node *);
98 
99 void
100 ath_rate_node_init(struct ath_softc *sc, struct ath_node *an)
101 {
102 	/* NB: assumed to be zero'd by caller */
103 }
104 
105 void
106 ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an)
107 {
108 }
109 
110 void
111 ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
112 	int shortPreamble, size_t frameLen,
113 	u_int8_t *rix, int *try0, u_int8_t *txrate)
114 {
115 	struct onoe_node *on = ATH_NODE_ONOE(an);
116 
117 	*rix = on->on_tx_rix0;
118 	*try0 = on->on_tx_try0;
119 	if (shortPreamble)
120 		*txrate = on->on_tx_rate0sp;
121 	else
122 		*txrate = on->on_tx_rate0;
123 }
124 
125 /*
126  * Get the TX rates.
127  *
128  * The short preamble bits aren't set here; the caller should augment
129  * the returned rate with the relevant preamble rate flag.
130  */
131 void
132 ath_rate_getxtxrates(struct ath_softc *sc, struct ath_node *an,
133     uint8_t rix0, struct ath_rc_series *rc)
134 {
135 	struct onoe_node *on = ATH_NODE_ONOE(an);
136 
137 	rc[0].flags = rc[1].flags = rc[2].flags = rc[3].flags = 0;
138 
139 	rc[0].rix = on->on_tx_rate0;
140 	rc[1].rix = on->on_tx_rate1;
141 	rc[2].rix = on->on_tx_rate2;
142 	rc[3].rix = on->on_tx_rate3;
143 
144 	rc[0].tries = on->on_tx_try0;
145 	rc[1].tries = 2;
146 	rc[2].tries = 2;
147 	rc[3].tries = 2;
148 }
149 
150 void
151 ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
152 	struct ath_desc *ds, int shortPreamble, u_int8_t rix)
153 {
154 	struct onoe_node *on = ATH_NODE_ONOE(an);
155 
156 	ath_hal_setupxtxdesc(sc->sc_ah, ds
157 		, on->on_tx_rate1sp, 2	/* series 1 */
158 		, on->on_tx_rate2sp, 2	/* series 2 */
159 		, on->on_tx_rate3sp, 2	/* series 3 */
160 	);
161 }
162 
163 void
164 ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
165 	const struct ath_rc_series *rc, const struct ath_tx_status *ts,
166 	int frame_size, int nframes, int nbad)
167 {
168 	struct onoe_node *on = ATH_NODE_ONOE(an);
169 
170 	if (ts->ts_status == 0)
171 		on->on_tx_ok++;
172 	else
173 		on->on_tx_err++;
174 	on->on_tx_retr += ts->ts_shortretry
175 			+ ts->ts_longretry;
176 	if (on->on_interval != 0 && ticks - on->on_ticks > on->on_interval) {
177 		ath_rate_ctl(sc, &an->an_node);
178 		on->on_ticks = ticks;
179 	}
180 }
181 
182 void
183 ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
184 {
185 	if (isnew)
186 		ath_rate_ctl_start(sc, &an->an_node);
187 }
188 
189 static void
190 ath_rate_update(struct ath_softc *sc, struct ieee80211_node *ni, int rate)
191 {
192 	struct ath_node *an = ATH_NODE(ni);
193 	struct onoe_node *on = ATH_NODE_ONOE(an);
194 	struct ieee80211vap *vap = ni->ni_vap;
195 	const HAL_RATE_TABLE *rt = sc->sc_currates;
196 	u_int8_t rix;
197 
198 	KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
199 
200 	IEEE80211_NOTE(vap, IEEE80211_MSG_RATECTL, ni,
201 	     "%s: set xmit rate to %dM", __func__,
202 	     ni->ni_rates.rs_nrates > 0 ?
203 		(ni->ni_rates.rs_rates[rate] & IEEE80211_RATE_VAL) / 2 : 0);
204 
205 	/*
206 	 * Before associating a node has no rate set setup
207 	 * so we can't calculate any transmit codes to use.
208 	 * This is ok since we should never be sending anything
209 	 * but management frames and those always go at the
210 	 * lowest hardware rate.
211 	 */
212 	if (ni->ni_rates.rs_nrates == 0)
213 		goto done;
214 	on->on_rix = rate;
215 	ni->ni_txrate = ni->ni_rates.rs_rates[rate] & IEEE80211_RATE_VAL;
216 	on->on_tx_rix0 = sc->sc_rixmap[ni->ni_txrate];
217 	on->on_tx_rate0 = rt->info[on->on_tx_rix0].rateCode;
218 
219 	on->on_tx_rate0sp = on->on_tx_rate0 |
220 		rt->info[on->on_tx_rix0].shortPreamble;
221 	if (sc->sc_mrretry) {
222 		/*
223 		 * Hardware supports multi-rate retry; setup two
224 		 * step-down retry rates and make the lowest rate
225 		 * be the ``last chance''.  We use 4, 2, 2, 2 tries
226 		 * respectively (4 is set here, the rest are fixed
227 		 * in the xmit routine).
228 		 */
229 		on->on_tx_try0 = 1 + 3;		/* 4 tries at rate 0 */
230 		if (--rate >= 0) {
231 			rix = sc->sc_rixmap[
232 				ni->ni_rates.rs_rates[rate]&IEEE80211_RATE_VAL];
233 			on->on_tx_rate1 = rt->info[rix].rateCode;
234 			on->on_tx_rate1sp = on->on_tx_rate1 |
235 				rt->info[rix].shortPreamble;
236 		} else {
237 			on->on_tx_rate1 = on->on_tx_rate1sp = 0;
238 		}
239 		if (--rate >= 0) {
240 			rix = sc->sc_rixmap[
241 				ni->ni_rates.rs_rates[rate]&IEEE80211_RATE_VAL];
242 			on->on_tx_rate2 = rt->info[rix].rateCode;
243 			on->on_tx_rate2sp = on->on_tx_rate2 |
244 				rt->info[rix].shortPreamble;
245 		} else {
246 			on->on_tx_rate2 = on->on_tx_rate2sp = 0;
247 		}
248 		if (rate > 0) {
249 			/* NB: only do this if we didn't already do it above */
250 			on->on_tx_rate3 = rt->info[0].rateCode;
251 			on->on_tx_rate3sp =
252 				on->on_tx_rate3 | rt->info[0].shortPreamble;
253 		} else {
254 			on->on_tx_rate3 = on->on_tx_rate3sp = 0;
255 		}
256 	} else {
257 		on->on_tx_try0 = ATH_TXMAXTRY;	/* max tries at rate 0 */
258 		on->on_tx_rate1 = on->on_tx_rate1sp = 0;
259 		on->on_tx_rate2 = on->on_tx_rate2sp = 0;
260 		on->on_tx_rate3 = on->on_tx_rate3sp = 0;
261 	}
262 done:
263 	on->on_tx_ok = on->on_tx_err = on->on_tx_retr = on->on_tx_upper = 0;
264 
265 	on->on_interval = ath_rateinterval;
266 	if (vap->iv_opmode == IEEE80211_M_STA)
267 		on->on_interval /= 2;
268 	on->on_interval = (on->on_interval * hz) / 1000;
269 }
270 
271 /*
272  * Set the starting transmit rate for a node.
273  */
274 static void
275 ath_rate_ctl_start(struct ath_softc *sc, struct ieee80211_node *ni)
276 {
277 #define	RATE(_ix)	(ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
278 	const struct ieee80211_txparam *tp = ni->ni_txparms;
279 	int srate;
280 
281 	KASSERT(ni->ni_rates.rs_nrates > 0, ("no rates"));
282 	if (tp == NULL || tp->ucastrate == IEEE80211_FIXED_RATE_NONE) {
283 		/*
284 		 * No fixed rate is requested. For 11b start with
285 		 * the highest negotiated rate; otherwise, for 11g
286 		 * and 11a, we start "in the middle" at 24Mb or 36Mb.
287 		 */
288 		srate = ni->ni_rates.rs_nrates - 1;
289 		if (sc->sc_curmode != IEEE80211_MODE_11B) {
290 			/*
291 			 * Scan the negotiated rate set to find the
292 			 * closest rate.
293 			 */
294 			/* NB: the rate set is assumed sorted */
295 			for (; srate >= 0 && RATE(srate) > 72; srate--)
296 				;
297 		}
298 	} else {
299 		/*
300 		 * A fixed rate is to be used; ic_fixed_rate is the
301 		 * IEEE code for this rate (sans basic bit).  Convert this
302 		 * to the index into the negotiated rate set for
303 		 * the node.  We know the rate is there because the
304 		 * rate set is checked when the station associates.
305 		 */
306 		/* NB: the rate set is assumed sorted */
307 		srate = ni->ni_rates.rs_nrates - 1;
308 		for (; srate >= 0 && RATE(srate) != tp->ucastrate; srate--)
309 			;
310 	}
311 	/*
312 	 * The selected rate may not be available due to races
313 	 * and mode settings.  Also orphaned nodes created in
314 	 * adhoc mode may not have any rate set so this lookup
315 	 * can fail.  This is not fatal.
316 	 */
317 	ath_rate_update(sc, ni, srate < 0 ? 0 : srate);
318 #undef RATE
319 }
320 
321 /*
322  * Examine and potentially adjust the transmit rate.
323  */
324 static void
325 ath_rate_ctl(void *arg, struct ieee80211_node *ni)
326 {
327 	struct ath_softc *sc = arg;
328 	struct onoe_node *on = ATH_NODE_ONOE(ATH_NODE(ni));
329 	struct ieee80211_rateset *rs = &ni->ni_rates;
330 	int dir = 0, nrate, enough;
331 
332 	/*
333 	 * Rate control
334 	 * XXX: very primitive version.
335 	 */
336 	enough = (on->on_tx_ok + on->on_tx_err >= 10);
337 
338 	/* no packet reached -> down */
339 	if (on->on_tx_err > 0 && on->on_tx_ok == 0)
340 		dir = -1;
341 
342 	/* all packets needs retry in average -> down */
343 	if (enough && on->on_tx_ok < on->on_tx_retr)
344 		dir = -1;
345 
346 	/* no error and less than rate_raise% of packets need retry -> up */
347 	if (enough && on->on_tx_err == 0 &&
348 	    on->on_tx_retr < (on->on_tx_ok * ath_rate_raise) / 100)
349 		dir = 1;
350 
351 	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
352 	    "ok %d err %d retr %d upper %d dir %d",
353 	    on->on_tx_ok, on->on_tx_err, on->on_tx_retr, on->on_tx_upper, dir);
354 
355 	nrate = on->on_rix;
356 	switch (dir) {
357 	case 0:
358 		if (enough && on->on_tx_upper > 0)
359 			on->on_tx_upper--;
360 		break;
361 	case -1:
362 		if (nrate > 0) {
363 			nrate--;
364 			sc->sc_stats.ast_rate_drop++;
365 		}
366 		on->on_tx_upper = 0;
367 		break;
368 	case 1:
369 		/* raise rate if we hit rate_raise_threshold */
370 		if (++on->on_tx_upper < ath_rate_raise_threshold)
371 			break;
372 		on->on_tx_upper = 0;
373 		if (nrate + 1 < rs->rs_nrates) {
374 			nrate++;
375 			sc->sc_stats.ast_rate_raise++;
376 		}
377 		break;
378 	}
379 
380 	if (nrate != on->on_rix) {
381 		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
382 		    "%s: %dM -> %dM (%d ok, %d err, %d retr)", __func__,
383 		    ni->ni_txrate / 2,
384 		    (rs->rs_rates[nrate] & IEEE80211_RATE_VAL) / 2,
385 		    on->on_tx_ok, on->on_tx_err, on->on_tx_retr);
386 		ath_rate_update(sc, ni, nrate);
387 	} else if (enough)
388 		on->on_tx_ok = on->on_tx_err = on->on_tx_retr = 0;
389 }
390 
391 static void
392 ath_rate_sysctlattach(struct ath_softc *sc)
393 {
394 	struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->sc_dev);
395 	struct sysctl_oid *tree = device_get_sysctl_tree(sc->sc_dev);
396 
397 	SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
398 		"rate_interval", CTLFLAG_RW, &ath_rateinterval, 0,
399 		"rate control: operation interval (ms)");
400 	/* XXX bounds check values */
401 	SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
402 		"rate_raise", CTLFLAG_RW, &ath_rate_raise, 0,
403 		"rate control: retry threshold to credit rate raise (%%)");
404 	SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
405 		"rate_raise_threshold", CTLFLAG_RW, &ath_rate_raise_threshold,0,
406 		"rate control: # good periods before raising rate");
407 }
408 
409 struct ath_ratectrl *
410 ath_rate_attach(struct ath_softc *sc)
411 {
412 	struct onoe_softc *osc;
413 
414 	osc = malloc(sizeof(struct onoe_softc), M_DEVBUF, M_NOWAIT|M_ZERO);
415 	if (osc == NULL)
416 		return NULL;
417 	osc->arc.arc_space = sizeof(struct onoe_node);
418 	ath_rate_sysctlattach(sc);
419 
420 	return &osc->arc;
421 }
422 
423 void
424 ath_rate_detach(struct ath_ratectrl *arc)
425 {
426 	struct onoe_softc *osc = (struct onoe_softc *) arc;
427 
428 	free(osc, M_DEVBUF);
429 }
430