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__FBSDID("$FreeBSD: stable/11/sys/net80211/ieee80211_amrr.c 359746 2020-04-09 15:30:21Z eugen $");
23
24/*-
25 * Naive implementation of the Adaptive Multi Rate Retry algorithm:
26 *
27 * "IEEE 802.11 Rate Adaptation: A Practical Approach"
28 *  Mathieu Lacage, Hossein Manshaei, Thierry Turletti
29 *  INRIA Sophia - Projet Planete
30 *  http://www-sop.inria.fr/rapports/sophia/RR-5208.html
31 */
32#include "opt_wlan.h"
33
34#include <sys/param.h>
35#include <sys/kernel.h>
36#include <sys/malloc.h>
37#include <sys/module.h>
38#include <sys/sbuf.h>
39#include <sys/socket.h>
40#include <sys/sysctl.h>
41
42#include <net/if.h>
43#include <net/if_var.h>
44#include <net/if_media.h>
45#include <net/ethernet.h>
46
47#ifdef INET
48#include <netinet/in.h>
49#include <netinet/if_ether.h>
50#endif
51
52#include <net80211/ieee80211_var.h>
53#include <net80211/ieee80211_ht.h>
54#include <net80211/ieee80211_amrr.h>
55#include <net80211/ieee80211_ratectl.h>
56
57#define is_success(amn)	\
58	((amn)->amn_retrycnt < (amn)->amn_txcnt / 10)
59#define is_failure(amn)	\
60	((amn)->amn_retrycnt > (amn)->amn_txcnt / 3)
61#define is_enough(amn)		\
62	((amn)->amn_txcnt > 10)
63
64static void	amrr_setinterval(const struct ieee80211vap *, int);
65static void	amrr_init(struct ieee80211vap *);
66static void	amrr_deinit(struct ieee80211vap *);
67static void	amrr_node_init(struct ieee80211_node *);
68static void	amrr_node_deinit(struct ieee80211_node *);
69static int	amrr_update(struct ieee80211_amrr *,
70    			struct ieee80211_amrr_node *, struct ieee80211_node *);
71static int	amrr_rate(struct ieee80211_node *, void *, uint32_t);
72static void	amrr_tx_complete(const struct ieee80211vap *,
73    			const struct ieee80211_node *, int,
74			void *, void *);
75static void	amrr_tx_update(const struct ieee80211vap *vap,
76			const struct ieee80211_node *, void *, void *, void *);
77static void	amrr_sysctlattach(struct ieee80211vap *,
78			struct sysctl_ctx_list *, struct sysctl_oid *);
79static void	amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s);
80
81/* number of references from net80211 layer */
82static	int nrefs = 0;
83
84static const struct ieee80211_ratectl amrr = {
85	.ir_name	= "amrr",
86	.ir_attach	= NULL,
87	.ir_detach	= NULL,
88	.ir_init	= amrr_init,
89	.ir_deinit	= amrr_deinit,
90	.ir_node_init	= amrr_node_init,
91	.ir_node_deinit	= amrr_node_deinit,
92	.ir_rate	= amrr_rate,
93	.ir_tx_complete	= amrr_tx_complete,
94	.ir_tx_update	= amrr_tx_update,
95	.ir_setinterval	= amrr_setinterval,
96	.ir_node_stats	= amrr_node_stats,
97};
98IEEE80211_RATECTL_MODULE(amrr, 1);
99IEEE80211_RATECTL_ALG(amrr, IEEE80211_RATECTL_AMRR, amrr);
100
101static void
102amrr_setinterval(const struct ieee80211vap *vap, int msecs)
103{
104	struct ieee80211_amrr *amrr = vap->iv_rs;
105	int t;
106
107	if (!amrr)
108		return;
109
110	if (msecs < 100)
111		msecs = 100;
112	t = msecs_to_ticks(msecs);
113	amrr->amrr_interval = (t < 1) ? 1 : t;
114}
115
116static void
117amrr_init(struct ieee80211vap *vap)
118{
119	struct ieee80211_amrr *amrr;
120
121	KASSERT(vap->iv_rs == NULL, ("%s called multiple times", __func__));
122
123	nrefs++;		/* XXX locking */
124	amrr = vap->iv_rs = IEEE80211_MALLOC(sizeof(struct ieee80211_amrr),
125	    M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
126	if (amrr == NULL) {
127		if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
128		return;
129	}
130	amrr->amrr_min_success_threshold = IEEE80211_AMRR_MIN_SUCCESS_THRESHOLD;
131	amrr->amrr_max_success_threshold = IEEE80211_AMRR_MAX_SUCCESS_THRESHOLD;
132	amrr_setinterval(vap, 500 /* ms */);
133	amrr_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
134}
135
136static void
137amrr_deinit(struct ieee80211vap *vap)
138{
139	IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
140	KASSERT(nrefs > 0, ("imbalanced attach/detach"));
141	nrefs--;		/* XXX locking */
142}
143
144/*
145 * Return whether 11n rates are possible.
146 *
147 * Some 11n devices may return HT information but no HT rates.
148 * Thus, we shouldn't treat them as an 11n node.
149 */
150static int
151amrr_node_is_11n(struct ieee80211_node *ni)
152{
153
154	if (ni->ni_chan == NULL)
155		return (0);
156	if (ni->ni_chan == IEEE80211_CHAN_ANYC)
157		return (0);
158	if (IEEE80211_IS_CHAN_HT(ni->ni_chan) && ni->ni_htrates.rs_nrates == 0)
159		return (0);
160	return (IEEE80211_IS_CHAN_HT(ni->ni_chan));
161}
162
163static void
164amrr_node_init(struct ieee80211_node *ni)
165{
166	const struct ieee80211_rateset *rs = NULL;
167	struct ieee80211vap *vap = ni->ni_vap;
168	struct ieee80211_amrr *amrr = vap->iv_rs;
169	struct ieee80211_amrr_node *amn;
170	uint8_t rate;
171
172	if (!amrr) {
173		if_printf(vap->iv_ifp, "ratectl structure was not allocated, "
174		    "per-node structure allocation skipped\n");
175		return;
176	}
177
178	if (ni->ni_rctls == NULL) {
179		ni->ni_rctls = amn = IEEE80211_MALLOC(sizeof(struct ieee80211_amrr_node),
180		    M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
181		if (amn == NULL) {
182			if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
183			    "structure\n");
184			return;
185		}
186	} else
187		amn = ni->ni_rctls;
188	amn->amn_amrr = amrr;
189	amn->amn_success = 0;
190	amn->amn_recovery = 0;
191	amn->amn_txcnt = amn->amn_retrycnt = 0;
192	amn->amn_success_threshold = amrr->amrr_min_success_threshold;
193
194	/* 11n or not? Pick the right rateset */
195	if (amrr_node_is_11n(ni)) {
196		/* XXX ew */
197		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
198		    "%s: 11n node", __func__);
199		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
200	} else {
201		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
202		    "%s: non-11n node", __func__);
203		rs = &ni->ni_rates;
204	}
205
206	/* Initial rate - lowest */
207	rate = rs->rs_rates[0];
208
209	/* XXX clear the basic rate flag if it's not 11n */
210	if (! amrr_node_is_11n(ni))
211		rate &= IEEE80211_RATE_VAL;
212
213	/* pick initial rate from the rateset - HT or otherwise */
214	/* Pick something low that's likely to succeed */
215	for (amn->amn_rix = rs->rs_nrates - 1; amn->amn_rix > 0;
216	    amn->amn_rix--) {
217		/* legacy - anything < 36mbit, stop searching */
218		/* 11n - stop at MCS4 */
219		if (amrr_node_is_11n(ni)) {
220			if ((rs->rs_rates[amn->amn_rix] & 0x1f) < 4)
221				break;
222		} else if ((rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) <= 72)
223			break;
224	}
225	rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
226
227	/* if the rate is an 11n rate, ensure the MCS bit is set */
228	if (amrr_node_is_11n(ni))
229		rate |= IEEE80211_RATE_MCS;
230
231	/* Assign initial rate from the rateset */
232	ni->ni_txrate = rate;
233	amn->amn_ticks = ticks;
234
235	/* XXX TODO: we really need a rate-to-string method */
236	/* XXX TODO: non-11n rate should be divided by two.. */
237	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
238	    "AMRR: nrates=%d, initial rate %s%d",
239	    rs->rs_nrates,
240	    amrr_node_is_11n(ni) ? "MCS " : "",
241	    rate & IEEE80211_RATE_VAL);
242}
243
244static void
245amrr_node_deinit(struct ieee80211_node *ni)
246{
247	IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
248}
249
250static int
251amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
252    struct ieee80211_node *ni)
253{
254	int rix = amn->amn_rix;
255	const struct ieee80211_rateset *rs = NULL;
256
257	KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
258
259	/* 11n or not? Pick the right rateset */
260	if (amrr_node_is_11n(ni)) {
261		/* XXX ew */
262		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
263	} else {
264		rs = &ni->ni_rates;
265	}
266
267	/* XXX TODO: we really need a rate-to-string method */
268	/* XXX TODO: non-11n rate should be divided by two.. */
269	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
270	    "AMRR: current rate %d, txcnt=%d, retrycnt=%d",
271	    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
272	    amn->amn_txcnt,
273	    amn->amn_retrycnt);
274
275	/*
276	 * XXX This is totally bogus for 11n, as although high MCS
277	 * rates for each stream may be failing, the next stream
278	 * should be checked.
279	 *
280	 * Eg, if MCS5 is ok but MCS6/7 isn't, and we can go up to
281	 * MCS23, we should skip 6/7 and try 8 onwards.
282	 */
283	if (is_success(amn)) {
284		amn->amn_success++;
285		if (amn->amn_success >= amn->amn_success_threshold &&
286		    rix + 1 < rs->rs_nrates) {
287			amn->amn_recovery = 1;
288			amn->amn_success = 0;
289			rix++;
290			/* XXX TODO: we really need a rate-to-string method */
291			/* XXX TODO: non-11n rate should be divided by two.. */
292			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
293			    "AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
294			    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
295			    amn->amn_txcnt, amn->amn_retrycnt);
296		} else {
297			amn->amn_recovery = 0;
298		}
299	} else if (is_failure(amn)) {
300		amn->amn_success = 0;
301		if (rix > 0) {
302			if (amn->amn_recovery) {
303				amn->amn_success_threshold *= 2;
304				if (amn->amn_success_threshold >
305				    amrr->amrr_max_success_threshold)
306					amn->amn_success_threshold =
307					    amrr->amrr_max_success_threshold;
308			} else {
309				amn->amn_success_threshold =
310				    amrr->amrr_min_success_threshold;
311			}
312			rix--;
313			/* XXX TODO: we really need a rate-to-string method */
314			/* XXX TODO: non-11n rate should be divided by two.. */
315			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
316			    "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
317			    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
318			    amn->amn_txcnt, amn->amn_retrycnt);
319		}
320		amn->amn_recovery = 0;
321	}
322
323	/* reset counters */
324	amn->amn_txcnt = 0;
325	amn->amn_retrycnt = 0;
326
327	return rix;
328}
329
330/*
331 * Return the rate index to use in sending a data frame.
332 * Update our internal state if it's been long enough.
333 * If the rate changes we also update ni_txrate to match.
334 */
335static int
336amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
337{
338	struct ieee80211_amrr_node *amn = ni->ni_rctls;
339	struct ieee80211_amrr *amrr;
340	const struct ieee80211_rateset *rs = NULL;
341	int rix;
342
343	/* XXX should return -1 here, but drivers may not expect this... */
344	if (!amn)
345	{
346		ni->ni_txrate = ni->ni_rates.rs_rates[0];
347		return 0;
348	}
349
350	amrr = amn->amn_amrr;
351
352	/* 11n or not? Pick the right rateset */
353	if (amrr_node_is_11n(ni)) {
354		/* XXX ew */
355		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
356	} else {
357		rs = &ni->ni_rates;
358	}
359
360	if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
361		rix = amrr_update(amrr, amn, ni);
362		if (rix != amn->amn_rix) {
363			/* update public rate */
364			ni->ni_txrate = rs->rs_rates[rix];
365			/* XXX strip basic rate flag from txrate, if non-11n */
366			if (amrr_node_is_11n(ni))
367				ni->ni_txrate |= IEEE80211_RATE_MCS;
368			else
369				ni->ni_txrate &= IEEE80211_RATE_VAL;
370			amn->amn_rix = rix;
371		}
372		amn->amn_ticks = ticks;
373	} else
374		rix = amn->amn_rix;
375	return rix;
376}
377
378/*
379 * Update statistics with tx complete status.  Ok is non-zero
380 * if the packet is known to be ACK'd.  Retries has the number
381 * retransmissions (i.e. xmit attempts - 1).
382 */
383static void
384amrr_tx_complete(const struct ieee80211vap *vap,
385    const struct ieee80211_node *ni, int ok,
386    void *arg1, void *arg2 __unused)
387{
388	struct ieee80211_amrr_node *amn = ni->ni_rctls;
389	int retries = *(int *)arg1;
390
391	if (!amn)
392		return;
393
394	amn->amn_txcnt++;
395	if (ok)
396		amn->amn_success++;
397	amn->amn_retrycnt += retries;
398}
399
400/*
401 * Set tx count/retry statistics explicitly.  Intended for
402 * drivers that poll the device for statistics maintained
403 * in the device.
404 */
405static void
406amrr_tx_update(const struct ieee80211vap *vap, const struct ieee80211_node *ni,
407    void *arg1, void *arg2, void *arg3)
408{
409	struct ieee80211_amrr_node *amn = ni->ni_rctls;
410	int txcnt = *(int *)arg1, success = *(int *)arg2, retrycnt = *(int *)arg3;
411
412	if (!amn)
413		return;
414
415	amn->amn_txcnt = txcnt;
416	amn->amn_success = success;
417	amn->amn_retrycnt = retrycnt;
418}
419
420static int
421amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)
422{
423	struct ieee80211vap *vap = arg1;
424	struct ieee80211_amrr *amrr = vap->iv_rs;
425	int msecs, error;
426
427	if (!amrr)
428		return ENOMEM;
429
430	msecs = ticks_to_msecs(amrr->amrr_interval);
431	error = sysctl_handle_int(oidp, &msecs, 0, req);
432	if (error || !req->newptr)
433		return error;
434	amrr_setinterval(vap, msecs);
435	return 0;
436}
437
438static void
439amrr_sysctlattach(struct ieee80211vap *vap,
440    struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
441{
442	struct ieee80211_amrr *amrr = vap->iv_rs;
443
444	if (!amrr)
445		return;
446
447	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
448	    "amrr_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
449	    0, amrr_sysctl_interval, "I", "amrr operation interval (ms)");
450	/* XXX bounds check values */
451	SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
452	    "amrr_max_sucess_threshold", CTLFLAG_RW,
453	    &amrr->amrr_max_success_threshold, 0, "");
454	SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
455	    "amrr_min_sucess_threshold", CTLFLAG_RW,
456	    &amrr->amrr_min_success_threshold, 0, "");
457}
458
459static void
460amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s)
461{
462	int rate;
463	struct ieee80211_amrr_node *amn = ni->ni_rctls;
464	struct ieee80211_rateset *rs;
465
466	/* XXX TODO: check locking? */
467
468	if (!amn)
469		return;
470
471	/* XXX TODO: this should be a method */
472	if (amrr_node_is_11n(ni)) {
473		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
474		rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
475		sbuf_printf(s, "rate: MCS %d\n", rate);
476	} else {
477		rs = &ni->ni_rates;
478		rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
479		sbuf_printf(s, "rate: %d Mbit\n", rate / 2);
480	}
481
482	sbuf_printf(s, "ticks: %d\n", amn->amn_ticks);
483	sbuf_printf(s, "txcnt: %u\n", amn->amn_txcnt);
484	sbuf_printf(s, "success: %u\n", amn->amn_success);
485	sbuf_printf(s, "success_threshold: %u\n", amn->amn_success_threshold);
486	sbuf_printf(s, "recovery: %u\n", amn->amn_recovery);
487	sbuf_printf(s, "retry_cnt: %u\n", amn->amn_retrycnt);
488}
489