1/*	$OpenBSD: ieee80211_amrr.c,v 1.1 2006/06/17 19:07:19 damien Exp $	*/
2
3/*-
4 * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org>
5 * Copyright (c) 2006
6 *	Damien Bergamini <damien.bergamini@free.fr>
7 *
8 * Permission to use, copy, modify, and distribute this software for any
9 * purpose with or without fee is hereby granted, provided that the above
10 * copyright notice and this permission notice appear in all copies.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
13 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
14 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
15 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
16 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
17 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
18 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
19 */
20
21#include <sys/cdefs.h>
22/*-
23 * Naive implementation of the Adaptive Multi Rate Retry algorithm:
24 *
25 * "IEEE 802.11 Rate Adaptation: A Practical Approach"
26 *  Mathieu Lacage, Hossein Manshaei, Thierry Turletti
27 *  INRIA Sophia - Projet Planete
28 *  http://www-sop.inria.fr/rapports/sophia/RR-5208.html
29 */
30#include "opt_wlan.h"
31
32#include <sys/param.h>
33#include <sys/kernel.h>
34#include <sys/malloc.h>
35#include <sys/module.h>
36#include <sys/sbuf.h>
37#include <sys/socket.h>
38#include <sys/sysctl.h>
39
40#include <net/if.h>
41#include <net/if_var.h>
42#include <net/if_media.h>
43#include <net/ethernet.h>
44
45#ifdef INET
46#include <netinet/in.h>
47#include <netinet/if_ether.h>
48#endif
49
50#include <net80211/ieee80211_var.h>
51#include <net80211/ieee80211_ht.h>
52#include <net80211/ieee80211_amrr.h>
53#include <net80211/ieee80211_ratectl.h>
54
55#define is_success(amn)	\
56	((amn)->amn_retrycnt < (amn)->amn_txcnt / 10)
57#define is_failure(amn)	\
58	((amn)->amn_retrycnt > (amn)->amn_txcnt / 3)
59#define is_enough(amn)		\
60	((amn)->amn_txcnt > 10)
61
62static void	amrr_setinterval(const struct ieee80211vap *, int);
63static void	amrr_init(struct ieee80211vap *);
64static void	amrr_deinit(struct ieee80211vap *);
65static void	amrr_node_init(struct ieee80211_node *);
66static void	amrr_node_deinit(struct ieee80211_node *);
67static int	amrr_update(struct ieee80211_amrr *,
68    			struct ieee80211_amrr_node *, struct ieee80211_node *);
69static int	amrr_rate(struct ieee80211_node *, void *, uint32_t);
70static void	amrr_tx_complete(const struct ieee80211_node *,
71			const struct ieee80211_ratectl_tx_status *);
72static void	amrr_tx_update_cb(void *, struct ieee80211_node *);
73static void	amrr_tx_update(struct ieee80211vap *vap,
74			struct ieee80211_ratectl_tx_stats *);
75static void	amrr_sysctlattach(struct ieee80211vap *,
76			struct sysctl_ctx_list *, struct sysctl_oid *);
77static void	amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s);
78
79/* number of references from net80211 layer */
80static	int nrefs = 0;
81
82static const struct ieee80211_ratectl amrr = {
83	.ir_name	= "amrr",
84	.ir_attach	= NULL,
85	.ir_detach	= NULL,
86	.ir_init	= amrr_init,
87	.ir_deinit	= amrr_deinit,
88	.ir_node_init	= amrr_node_init,
89	.ir_node_deinit	= amrr_node_deinit,
90	.ir_rate	= amrr_rate,
91	.ir_tx_complete	= amrr_tx_complete,
92	.ir_tx_update	= amrr_tx_update,
93	.ir_setinterval	= amrr_setinterval,
94	.ir_node_stats	= amrr_node_stats,
95};
96IEEE80211_RATECTL_MODULE(amrr, 1);
97IEEE80211_RATECTL_ALG(amrr, IEEE80211_RATECTL_AMRR, amrr);
98
99static void
100amrr_setinterval(const struct ieee80211vap *vap, int msecs)
101{
102	struct ieee80211_amrr *amrr = vap->iv_rs;
103
104	if (!amrr)
105		return;
106
107	if (msecs < 100)
108		msecs = 100;
109	amrr->amrr_interval = msecs_to_ticks(msecs);
110}
111
112static void
113amrr_init(struct ieee80211vap *vap)
114{
115	struct ieee80211_amrr *amrr;
116
117	KASSERT(vap->iv_rs == NULL, ("%s called multiple times", __func__));
118
119	nrefs++;		/* XXX locking */
120	amrr = vap->iv_rs = IEEE80211_MALLOC(sizeof(struct ieee80211_amrr),
121	    M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
122	if (amrr == NULL) {
123		if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
124		return;
125	}
126	amrr->amrr_min_success_threshold = IEEE80211_AMRR_MIN_SUCCESS_THRESHOLD;
127	amrr->amrr_max_success_threshold = IEEE80211_AMRR_MAX_SUCCESS_THRESHOLD;
128	amrr_setinterval(vap, 500 /* ms */);
129	amrr_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
130}
131
132static void
133amrr_deinit(struct ieee80211vap *vap)
134{
135	KASSERT(nrefs > 0, ("imbalanced attach/detach"));
136	IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
137	vap->iv_rs = NULL;	/* guard */
138	nrefs--;		/* XXX locking */
139}
140
141/*
142 * Return whether 11n rates are possible.
143 *
144 * Some 11n devices may return HT information but no HT rates.
145 * Thus, we shouldn't treat them as an 11n node.
146 */
147static int
148amrr_node_is_11n(struct ieee80211_node *ni)
149{
150
151	if (ni->ni_chan == NULL)
152		return (0);
153	if (ni->ni_chan == IEEE80211_CHAN_ANYC)
154		return (0);
155	if (IEEE80211_IS_CHAN_HT(ni->ni_chan) && ni->ni_htrates.rs_nrates == 0)
156		return (0);
157	return (IEEE80211_IS_CHAN_HT(ni->ni_chan));
158}
159
160static void
161amrr_node_init(struct ieee80211_node *ni)
162{
163	const struct ieee80211_rateset *rs = NULL;
164	struct ieee80211vap *vap = ni->ni_vap;
165	struct ieee80211_amrr *amrr = vap->iv_rs;
166	struct ieee80211_amrr_node *amn;
167	uint8_t rate;
168
169	if (!amrr) {
170		if_printf(vap->iv_ifp, "ratectl structure was not allocated, "
171		    "per-node structure allocation skipped\n");
172		return;
173	}
174
175	if (ni->ni_rctls == NULL) {
176		ni->ni_rctls = amn = IEEE80211_MALLOC(sizeof(struct ieee80211_amrr_node),
177		    M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
178		if (amn == NULL) {
179			if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
180			    "structure\n");
181			return;
182		}
183	} else
184		amn = ni->ni_rctls;
185	amn->amn_amrr = amrr;
186	amn->amn_success = 0;
187	amn->amn_recovery = 0;
188	amn->amn_txcnt = amn->amn_retrycnt = 0;
189	amn->amn_success_threshold = amrr->amrr_min_success_threshold;
190
191	/* 11n or not? Pick the right rateset */
192	if (amrr_node_is_11n(ni)) {
193		/* XXX ew */
194		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
195		    "%s: 11n node", __func__);
196		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
197	} else {
198		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
199		    "%s: non-11n node", __func__);
200		rs = &ni->ni_rates;
201	}
202
203	/* Initial rate - lowest */
204	rate = rs->rs_rates[0];
205
206	/* XXX clear the basic rate flag if it's not 11n */
207	if (! amrr_node_is_11n(ni))
208		rate &= IEEE80211_RATE_VAL;
209
210	/* pick initial rate from the rateset - HT or otherwise */
211	/* Pick something low that's likely to succeed */
212	for (amn->amn_rix = rs->rs_nrates - 1; amn->amn_rix > 0;
213	    amn->amn_rix--) {
214		/* legacy - anything < 36mbit, stop searching */
215		/* 11n - stop at MCS4 */
216		if (amrr_node_is_11n(ni)) {
217			if ((rs->rs_rates[amn->amn_rix] & 0x1f) < 4)
218				break;
219		} else if ((rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) <= 72)
220			break;
221	}
222	rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
223
224	/* if the rate is an 11n rate, ensure the MCS bit is set */
225	if (amrr_node_is_11n(ni))
226		rate |= IEEE80211_RATE_MCS;
227
228	/* Assign initial rate from the rateset */
229	ni->ni_txrate = rate;
230	amn->amn_ticks = ticks;
231
232	/* XXX TODO: we really need a rate-to-string method */
233	/* XXX TODO: non-11n rate should be divided by two.. */
234	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
235	    "AMRR: nrates=%d, initial rate %s%d",
236	    rs->rs_nrates,
237	    amrr_node_is_11n(ni) ? "MCS " : "",
238	    rate & IEEE80211_RATE_VAL);
239}
240
241static void
242amrr_node_deinit(struct ieee80211_node *ni)
243{
244	IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
245}
246
247static int
248amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
249    struct ieee80211_node *ni)
250{
251	int rix = amn->amn_rix;
252	const struct ieee80211_rateset *rs = NULL;
253
254	KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
255
256	/* 11n or not? Pick the right rateset */
257	if (amrr_node_is_11n(ni)) {
258		/* XXX ew */
259		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
260	} else {
261		rs = &ni->ni_rates;
262	}
263
264	/* XXX TODO: we really need a rate-to-string method */
265	/* XXX TODO: non-11n rate should be divided by two.. */
266	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
267	    "AMRR: current rate %d, txcnt=%d, retrycnt=%d",
268	    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
269	    amn->amn_txcnt,
270	    amn->amn_retrycnt);
271
272	/*
273	 * XXX This is totally bogus for 11n, as although high MCS
274	 * rates for each stream may be failing, the next stream
275	 * should be checked.
276	 *
277	 * Eg, if MCS5 is ok but MCS6/7 isn't, and we can go up to
278	 * MCS23, we should skip 6/7 and try 8 onwards.
279	 */
280	if (is_success(amn)) {
281		amn->amn_success++;
282		if (amn->amn_success >= amn->amn_success_threshold &&
283		    rix + 1 < rs->rs_nrates) {
284			amn->amn_recovery = 1;
285			amn->amn_success = 0;
286			rix++;
287			/* XXX TODO: we really need a rate-to-string method */
288			/* XXX TODO: non-11n rate should be divided by two.. */
289			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
290			    "AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
291			    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
292			    amn->amn_txcnt, amn->amn_retrycnt);
293		} else {
294			amn->amn_recovery = 0;
295		}
296	} else if (is_failure(amn)) {
297		amn->amn_success = 0;
298		if (rix > 0) {
299			if (amn->amn_recovery) {
300				amn->amn_success_threshold *= 2;
301				if (amn->amn_success_threshold >
302				    amrr->amrr_max_success_threshold)
303					amn->amn_success_threshold =
304					    amrr->amrr_max_success_threshold;
305			} else {
306				amn->amn_success_threshold =
307				    amrr->amrr_min_success_threshold;
308			}
309			rix--;
310			/* XXX TODO: we really need a rate-to-string method */
311			/* XXX TODO: non-11n rate should be divided by two.. */
312			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
313			    "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
314			    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
315			    amn->amn_txcnt, amn->amn_retrycnt);
316		}
317		amn->amn_recovery = 0;
318	}
319
320	/* reset counters */
321	amn->amn_txcnt = 0;
322	amn->amn_retrycnt = 0;
323
324	return rix;
325}
326
327/*
328 * Return the rate index to use in sending a data frame.
329 * Update our internal state if it's been long enough.
330 * If the rate changes we also update ni_txrate to match.
331 */
332static int
333amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
334{
335	struct ieee80211_amrr_node *amn = ni->ni_rctls;
336	struct ieee80211_amrr *amrr;
337	const struct ieee80211_rateset *rs = NULL;
338	int rix;
339
340	/* XXX should return -1 here, but drivers may not expect this... */
341	if (!amn)
342	{
343		ni->ni_txrate = ni->ni_rates.rs_rates[0];
344		return 0;
345	}
346
347	amrr = amn->amn_amrr;
348
349	/* 11n or not? Pick the right rateset */
350	if (amrr_node_is_11n(ni)) {
351		/* XXX ew */
352		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
353	} else {
354		rs = &ni->ni_rates;
355	}
356
357	if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
358		rix = amrr_update(amrr, amn, ni);
359		if (rix != amn->amn_rix) {
360			/* update public rate */
361			ni->ni_txrate = rs->rs_rates[rix];
362			/* XXX strip basic rate flag from txrate, if non-11n */
363			if (amrr_node_is_11n(ni))
364				ni->ni_txrate |= IEEE80211_RATE_MCS;
365			else
366				ni->ni_txrate &= IEEE80211_RATE_VAL;
367			amn->amn_rix = rix;
368		}
369		amn->amn_ticks = ticks;
370	} else
371		rix = amn->amn_rix;
372	return rix;
373}
374
375/*
376 * Update statistics with tx complete status.  Ok is non-zero
377 * if the packet is known to be ACK'd.  Retries has the number
378 * retransmissions (i.e. xmit attempts - 1).
379 */
380static void
381amrr_tx_complete(const struct ieee80211_node *ni,
382    const struct ieee80211_ratectl_tx_status *status)
383{
384	struct ieee80211_amrr_node *amn = ni->ni_rctls;
385	int retries;
386
387	if (!amn)
388		return;
389
390	retries = 0;
391	if (status->flags & IEEE80211_RATECTL_STATUS_LONG_RETRY)
392		retries = status->long_retries;
393
394	amn->amn_txcnt++;
395	if (status->status == IEEE80211_RATECTL_TX_SUCCESS)
396		amn->amn_success++;
397	amn->amn_retrycnt += retries;
398}
399
400static void
401amrr_tx_update_cb(void *arg, struct ieee80211_node *ni)
402{
403	struct ieee80211_ratectl_tx_stats *stats = arg;
404	struct ieee80211_amrr_node *amn = ni->ni_rctls;
405	int txcnt, success, retrycnt;
406
407	if (!amn)
408		return;
409
410	txcnt = stats->nframes;
411	success = stats->nsuccess;
412	retrycnt = 0;
413	if (stats->flags & IEEE80211_RATECTL_TX_STATS_RETRIES)
414		retrycnt = stats->nretries;
415
416	amn->amn_txcnt += txcnt;
417	amn->amn_success += success;
418	amn->amn_retrycnt += retrycnt;
419}
420
421/*
422 * Set tx count/retry statistics explicitly.  Intended for
423 * drivers that poll the device for statistics maintained
424 * in the device.
425 */
426static void
427amrr_tx_update(struct ieee80211vap *vap,
428    struct ieee80211_ratectl_tx_stats *stats)
429{
430
431	if (stats->flags & IEEE80211_RATECTL_TX_STATS_NODE)
432		amrr_tx_update_cb(stats, stats->ni);
433	else {
434		ieee80211_iterate_nodes_vap(&vap->iv_ic->ic_sta, vap,
435		    amrr_tx_update_cb, stats);
436	}
437}
438
439static int
440amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)
441{
442	struct ieee80211vap *vap = arg1;
443	struct ieee80211_amrr *amrr = vap->iv_rs;
444	int msecs, error;
445
446	if (!amrr)
447		return ENOMEM;
448
449	msecs = ticks_to_msecs(amrr->amrr_interval);
450	error = sysctl_handle_int(oidp, &msecs, 0, req);
451	if (error || !req->newptr)
452		return error;
453	amrr_setinterval(vap, msecs);
454	return 0;
455}
456
457static void
458amrr_sysctlattach(struct ieee80211vap *vap,
459    struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
460{
461	struct ieee80211_amrr *amrr = vap->iv_rs;
462
463	if (!amrr)
464		return;
465
466	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
467	    "amrr_rate_interval", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT,
468	    vap, 0, amrr_sysctl_interval, "I", "amrr operation interval (ms)");
469	/* XXX bounds check values */
470	SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
471	    "amrr_max_sucess_threshold", CTLFLAG_RW,
472	    &amrr->amrr_max_success_threshold, 0, "");
473	SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
474	    "amrr_min_sucess_threshold", CTLFLAG_RW,
475	    &amrr->amrr_min_success_threshold, 0, "");
476}
477
478static void
479amrr_print_node_rate(struct ieee80211_amrr_node *amn,
480    struct ieee80211_node *ni, struct sbuf *s)
481{
482	int rate;
483	struct ieee80211_rateset *rs;
484
485	if (amrr_node_is_11n(ni)) {
486		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
487		rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
488		sbuf_printf(s, "rate: MCS %d\n", rate);
489	} else {
490		rs = &ni->ni_rates;
491		rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
492		sbuf_printf(s, "rate: %d Mbit\n", rate / 2);
493	}
494}
495
496static void
497amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s)
498{
499	struct ieee80211_amrr_node *amn = ni->ni_rctls;
500
501	/* XXX TODO: check locking? */
502
503	if (!amn)
504		return;
505
506	amrr_print_node_rate(amn, ni, s);
507	sbuf_printf(s, "ticks: %d\n", amn->amn_ticks);
508	sbuf_printf(s, "txcnt: %u\n", amn->amn_txcnt);
509	sbuf_printf(s, "success: %u\n", amn->amn_success);
510	sbuf_printf(s, "success_threshold: %u\n", amn->amn_success_threshold);
511	sbuf_printf(s, "recovery: %u\n", amn->amn_recovery);
512	sbuf_printf(s, "retry_cnt: %u\n", amn->amn_retrycnt);
513}
514