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("$FreeBSD$");
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 #include <netproto/802_11/ieee80211_var.h>
48 #include <netproto/802_11/ieee80211_ht.h>
49 #include <netproto/802_11/ieee80211_amrr.h>
50 #include <netproto/802_11/ieee80211_ratectl.h>
51 
52 #define is_success(amn)	\
53 	((amn)->amn_retrycnt < (amn)->amn_txcnt / 10)
54 #define is_failure(amn)	\
55 	((amn)->amn_retrycnt > (amn)->amn_txcnt / 3)
56 #define is_enough(amn)		\
57 	((amn)->amn_txcnt > 10)
58 
59 static void	amrr_setinterval(const struct ieee80211vap *, int);
60 static void	amrr_init(struct ieee80211vap *);
61 static void	amrr_deinit(struct ieee80211vap *);
62 static void	amrr_node_init(struct ieee80211_node *);
63 static void	amrr_node_deinit(struct ieee80211_node *);
64 static int	amrr_update(struct ieee80211_amrr *,
65     			struct ieee80211_amrr_node *, struct ieee80211_node *);
66 static int	amrr_rate(struct ieee80211_node *, void *, uint32_t);
67 static void	amrr_tx_complete(const struct ieee80211vap *,
68     			const struct ieee80211_node *, int,
69 			void *, void *);
70 static void	amrr_tx_update(const struct ieee80211vap *vap,
71 			const struct ieee80211_node *, void *, void *, void *);
72 static void	amrr_sysctlattach(struct ieee80211vap *,
73 			struct sysctl_ctx_list *, struct sysctl_oid *);
74 static void	amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s);
75 
76 /* number of references from net80211 layer */
77 static	int nrefs = 0;
78 
79 static const struct ieee80211_ratectl amrr = {
80 	.ir_name	= "amrr",
81 	.ir_attach	= NULL,
82 	.ir_detach	= NULL,
83 	.ir_init	= amrr_init,
84 	.ir_deinit	= amrr_deinit,
85 	.ir_node_init	= amrr_node_init,
86 	.ir_node_deinit	= amrr_node_deinit,
87 	.ir_rate	= amrr_rate,
88 	.ir_tx_complete	= amrr_tx_complete,
89 	.ir_tx_update	= amrr_tx_update,
90 	.ir_setinterval	= amrr_setinterval,
91 	.ir_node_stats  = amrr_node_stats,
92 };
93 IEEE80211_RATECTL_MODULE(amrr, 1);
94 IEEE80211_RATECTL_ALG(amrr, IEEE80211_RATECTL_AMRR, amrr);
95 
96 static void
97 amrr_setinterval(const struct ieee80211vap *vap, int msecs)
98 {
99 	struct ieee80211_amrr *amrr = vap->iv_rs;
100 	int t;
101 
102 	if (msecs < 100)
103 		msecs = 100;
104 	t = msecs_to_ticks(msecs);
105 	amrr->amrr_interval = (t < 1) ? 1 : t;
106 }
107 
108 static void
109 amrr_init(struct ieee80211vap *vap)
110 {
111 	struct ieee80211_amrr *amrr;
112 
113 	KASSERT(vap->iv_rs == NULL, ("%s called multiple times", __func__));
114 
115 #if defined(__DragonFly__)
116 	amrr = vap->iv_rs = kmalloc(sizeof(struct ieee80211_amrr),
117 	    M_80211_RATECTL, M_INTWAIT|M_ZERO);
118 #else
119 	amrr = vap->iv_rs = IEEE80211_MALLOC(sizeof(struct ieee80211_amrr),
120 	    M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
121 #endif
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 
132 static void
133 amrr_deinit(struct ieee80211vap *vap)
134 {
135 	IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
136 }
137 
138 /*
139  * Return whether 11n rates are possible.
140  *
141  * Some 11n devices may return HT information but no HT rates.
142  * Thus, we shouldn't treat them as an 11n node.
143  */
144 static int
145 amrr_node_is_11n(struct ieee80211_node *ni)
146 {
147 
148 	if (ni->ni_chan == NULL)
149 		return (0);
150 	if (ni->ni_chan == IEEE80211_CHAN_ANYC)
151 		return (0);
152 	if (IEEE80211_IS_CHAN_HT(ni->ni_chan) && ni->ni_htrates.rs_nrates == 0)
153 		return (0);
154 	return (IEEE80211_IS_CHAN_HT(ni->ni_chan));
155 }
156 
157 static void
158 amrr_node_init(struct ieee80211_node *ni)
159 {
160 	const struct ieee80211_rateset *rs = NULL;
161 	struct ieee80211vap *vap = ni->ni_vap;
162 	struct ieee80211_amrr *amrr = vap->iv_rs;
163 	struct ieee80211_amrr_node *amn;
164 	uint8_t rate;
165 
166 	if (ni->ni_rctls == NULL) {
167 #if defined(__DragonFly__)
168 		ni->ni_rctls = amn = kmalloc(sizeof(struct ieee80211_amrr_node),
169 		    M_80211_RATECTL, M_INTWAIT|M_ZERO);
170 #else
171 		ni->ni_rctls = amn = IEEE80211_MALLOC(sizeof(struct ieee80211_amrr_node),
172 		    M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
173 #endif
174 		if (amn == NULL) {
175 			if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
176 			    "structure\n");
177 			return;
178 		}
179 	} else
180 		amn = ni->ni_rctls;
181 	amn->amn_amrr = amrr;
182 	amn->amn_success = 0;
183 	amn->amn_recovery = 0;
184 	amn->amn_txcnt = amn->amn_retrycnt = 0;
185 	amn->amn_success_threshold = amrr->amrr_min_success_threshold;
186 
187 	/* 11n or not? Pick the right rateset */
188 	if (amrr_node_is_11n(ni)) {
189 		/* XXX ew */
190 		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
191 		    "%s: 11n node", __func__);
192 		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
193 	} else {
194 		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
195 		    "%s: non-11n node", __func__);
196 		rs = &ni->ni_rates;
197 	}
198 
199 	/* Initial rate - lowest */
200 	rate = rs->rs_rates[0];
201 
202 	/* XXX clear the basic rate flag if it's not 11n */
203 	if (! amrr_node_is_11n(ni))
204 		rate &= IEEE80211_RATE_VAL;
205 
206 	/* pick initial rate from the rateset - HT or otherwise */
207 	/* Pick something low that's likely to succeed */
208 	for (amn->amn_rix = rs->rs_nrates - 1; amn->amn_rix > 0;
209 	    amn->amn_rix--) {
210 		/* legacy - anything < 36mbit, stop searching */
211 		/* 11n - stop at MCS4 */
212 		if (amrr_node_is_11n(ni)) {
213 			if ((rs->rs_rates[amn->amn_rix] & 0x1f) < 4)
214 				break;
215 		} else if ((rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) <= 72)
216 			break;
217 	}
218 	rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
219 
220 	/* if the rate is an 11n rate, ensure the MCS bit is set */
221 	if (amrr_node_is_11n(ni))
222 		rate |= IEEE80211_RATE_MCS;
223 
224 	/* Assign initial rate from the rateset */
225 	ni->ni_txrate = rate;
226 	amn->amn_ticks = ticks;
227 
228 	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
229 	    "AMRR: nrates=%d, initial rate %d",
230 	    rs->rs_nrates,
231 	    rate);
232 }
233 
234 static void
235 amrr_node_deinit(struct ieee80211_node *ni)
236 {
237 	IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
238 }
239 
240 static int
241 amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
242     struct ieee80211_node *ni)
243 {
244 	int rix = amn->amn_rix;
245 	const struct ieee80211_rateset *rs = NULL;
246 
247 	KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
248 
249 	/* 11n or not? Pick the right rateset */
250 	if (amrr_node_is_11n(ni)) {
251 		/* XXX ew */
252 		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
253 	} else {
254 		rs = &ni->ni_rates;
255 	}
256 
257 	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
258 	    "AMRR: current rate %d, txcnt=%d, retrycnt=%d",
259 	    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
260 	    amn->amn_txcnt,
261 	    amn->amn_retrycnt);
262 
263 	/*
264 	 * XXX This is totally bogus for 11n, as although high MCS
265 	 * rates for each stream may be failing, the next stream
266 	 * should be checked.
267 	 *
268 	 * Eg, if MCS5 is ok but MCS6/7 isn't, and we can go up to
269 	 * MCS23, we should skip 6/7 and try 8 onwards.
270 	 */
271 	if (is_success(amn)) {
272 		amn->amn_success++;
273 		if (amn->amn_success >= amn->amn_success_threshold &&
274 		    rix + 1 < rs->rs_nrates) {
275 			amn->amn_recovery = 1;
276 			amn->amn_success = 0;
277 			rix++;
278 			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
279 			    "AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
280 			    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
281 			    amn->amn_txcnt, amn->amn_retrycnt);
282 		} else {
283 			amn->amn_recovery = 0;
284 		}
285 	} else if (is_failure(amn)) {
286 		amn->amn_success = 0;
287 		if (rix > 0) {
288 			if (amn->amn_recovery) {
289 				amn->amn_success_threshold *= 2;
290 				if (amn->amn_success_threshold >
291 				    amrr->amrr_max_success_threshold)
292 					amn->amn_success_threshold =
293 					    amrr->amrr_max_success_threshold;
294 			} else {
295 				amn->amn_success_threshold =
296 				    amrr->amrr_min_success_threshold;
297 			}
298 			rix--;
299 			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
300 			    "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
301 			    rs->rs_rates[rix] & IEEE80211_RATE_VAL,
302 			    amn->amn_txcnt, amn->amn_retrycnt);
303 		}
304 		amn->amn_recovery = 0;
305 	}
306 
307 	/* reset counters */
308 	amn->amn_txcnt = 0;
309 	amn->amn_retrycnt = 0;
310 
311 	return rix;
312 }
313 
314 /*
315  * Return the rate index to use in sending a data frame.
316  * Update our internal state if it's been long enough.
317  * If the rate changes we also update ni_txrate to match.
318  */
319 static int
320 amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
321 {
322 	struct ieee80211_amrr_node *amn = ni->ni_rctls;
323 	struct ieee80211_amrr *amrr = amn->amn_amrr;
324 	const struct ieee80211_rateset *rs = NULL;
325 	int rix;
326 
327 	/* 11n or not? Pick the right rateset */
328 	if (amrr_node_is_11n(ni)) {
329 		/* XXX ew */
330 		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
331 	} else {
332 		rs = &ni->ni_rates;
333 	}
334 
335 	if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
336 		rix = amrr_update(amrr, amn, ni);
337 		if (rix != amn->amn_rix) {
338 			/* update public rate */
339 			ni->ni_txrate = rs->rs_rates[rix];
340 			/* XXX strip basic rate flag from txrate, if non-11n */
341 			if (amrr_node_is_11n(ni))
342 				ni->ni_txrate |= IEEE80211_RATE_MCS;
343 			else
344 				ni->ni_txrate &= IEEE80211_RATE_VAL;
345 			amn->amn_rix = rix;
346 		}
347 		amn->amn_ticks = ticks;
348 	} else
349 		rix = amn->amn_rix;
350 	return rix;
351 }
352 
353 /*
354  * Update statistics with tx complete status.  Ok is non-zero
355  * if the packet is known to be ACK'd.  Retries has the number
356  * retransmissions (i.e. xmit attempts - 1).
357  */
358 static void
359 amrr_tx_complete(const struct ieee80211vap *vap,
360     const struct ieee80211_node *ni, int ok,
361     void *arg1, void *arg2 __unused)
362 {
363 	struct ieee80211_amrr_node *amn = ni->ni_rctls;
364 	int retries = *(int *)arg1;
365 
366 	amn->amn_txcnt++;
367 	if (ok)
368 		amn->amn_success++;
369 	amn->amn_retrycnt += retries;
370 }
371 
372 /*
373  * Set tx count/retry statistics explicitly.  Intended for
374  * drivers that poll the device for statistics maintained
375  * in the device.
376  */
377 static void
378 amrr_tx_update(const struct ieee80211vap *vap, const struct ieee80211_node *ni,
379     void *arg1, void *arg2, void *arg3)
380 {
381 	struct ieee80211_amrr_node *amn = ni->ni_rctls;
382 	int txcnt = *(int *)arg1, success = *(int *)arg2, retrycnt = *(int *)arg3;
383 
384 	amn->amn_txcnt = txcnt;
385 	amn->amn_success = success;
386 	amn->amn_retrycnt = retrycnt;
387 }
388 
389 static int
390 amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)
391 {
392 	struct ieee80211vap *vap = arg1;
393 	struct ieee80211_amrr *amrr = vap->iv_rs;
394 	int msecs = ticks_to_msecs(amrr->amrr_interval);
395 	int error;
396 
397 	error = sysctl_handle_int(oidp, &msecs, 0, req);
398 	if (error || !req->newptr)
399 		return error;
400 	amrr_setinterval(vap, msecs);
401 	return 0;
402 }
403 
404 static void
405 amrr_sysctlattach(struct ieee80211vap *vap,
406     struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
407 {
408 	struct ieee80211_amrr *amrr = vap->iv_rs;
409 
410 	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
411 	    "amrr_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
412 	    0, amrr_sysctl_interval, "I", "amrr operation interval (ms)");
413 	/* XXX bounds check values */
414 	SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
415 	    "amrr_max_sucess_threshold", CTLFLAG_RW,
416 	    &amrr->amrr_max_success_threshold, 0, "");
417 	SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
418 	    "amrr_min_sucess_threshold", CTLFLAG_RW,
419 	    &amrr->amrr_min_success_threshold, 0, "");
420 }
421 
422 static void
423 amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s)
424 {
425 	int rate;
426 	struct ieee80211_amrr_node *amn = ni->ni_rctls;
427 	struct ieee80211_rateset *rs;
428 
429 	/* XXX TODO: check locking? */
430 
431 	/* XXX TODO: this should be a method */
432 	if (amrr_node_is_11n(ni)) {
433 		rs = (struct ieee80211_rateset *) &ni->ni_htrates;
434 		rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
435 		sbuf_printf(s, "rate: MCS %d\n", rate);
436 	} else {
437 		rs = &ni->ni_rates;
438 		rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
439 		sbuf_printf(s, "rate: %d Mbit\n", rate / 2);
440 	}
441 
442 	sbuf_printf(s, "ticks: %d\n", amn->amn_ticks);
443 	sbuf_printf(s, "txcnt: %u\n", amn->amn_txcnt);
444 	sbuf_printf(s, "success: %u\n", amn->amn_success);
445 	sbuf_printf(s, "success_threshold: %u\n", amn->amn_success_threshold);
446 	sbuf_printf(s, "recovery: %u\n", amn->amn_recovery);
447 	sbuf_printf(s, "retry_cnt: %u\n", amn->amn_retrycnt);
448 }
449