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
62 static void amrr_setinterval(const struct ieee80211vap *, int);
63 static void amrr_init(struct ieee80211vap *);
64 static void amrr_deinit(struct ieee80211vap *);
65 static void amrr_node_init(struct ieee80211_node *);
66 static void amrr_node_deinit(struct ieee80211_node *);
67 static int amrr_update(struct ieee80211_amrr *,
68 struct ieee80211_amrr_node *, struct ieee80211_node *);
69 static int amrr_rate(struct ieee80211_node *, void *, uint32_t);
70 static void amrr_tx_complete(const struct ieee80211_node *,
71 const struct ieee80211_ratectl_tx_status *);
72 static void amrr_tx_update_cb(void *, struct ieee80211_node *);
73 static void amrr_tx_update(struct ieee80211vap *vap,
74 struct ieee80211_ratectl_tx_stats *);
75 static void amrr_sysctlattach(struct ieee80211vap *,
76 struct sysctl_ctx_list *, struct sysctl_oid *);
77 static void amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s);
78
79 /* number of references from net80211 layer */
80 static int nrefs = 0;
81
82 static 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 };
96 IEEE80211_RATECTL_MODULE(amrr, 1);
97 IEEE80211_RATECTL_ALG(amrr, IEEE80211_RATECTL_AMRR, amrr);
98
99 static void
amrr_setinterval(const struct ieee80211vap * vap,int msecs)100 amrr_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
112 static void
amrr_init(struct ieee80211vap * vap)113 amrr_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
132 static void
amrr_deinit(struct ieee80211vap * vap)133 amrr_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 */
147 static int
amrr_node_is_11n(struct ieee80211_node * ni)148 amrr_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
160 static void
amrr_node_init(struct ieee80211_node * ni)161 amrr_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
241 static void
amrr_node_deinit(struct ieee80211_node * ni)242 amrr_node_deinit(struct ieee80211_node *ni)
243 {
244 IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
245 }
246
247 static int
amrr_update(struct ieee80211_amrr * amrr,struct ieee80211_amrr_node * amn,struct ieee80211_node * ni)248 amrr_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 */
332 static int
amrr_rate(struct ieee80211_node * ni,void * arg __unused,uint32_t iarg __unused)333 amrr_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 */
380 static void
amrr_tx_complete(const struct ieee80211_node * ni,const struct ieee80211_ratectl_tx_status * status)381 amrr_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
400 static void
amrr_tx_update_cb(void * arg,struct ieee80211_node * ni)401 amrr_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 */
426 static void
amrr_tx_update(struct ieee80211vap * vap,struct ieee80211_ratectl_tx_stats * stats)427 amrr_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
439 static int
amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)440 amrr_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
457 static void
amrr_sysctlattach(struct ieee80211vap * vap,struct sysctl_ctx_list * ctx,struct sysctl_oid * tree)458 amrr_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
478 static void
amrr_print_node_rate(struct ieee80211_amrr_node * amn,struct ieee80211_node * ni,struct sbuf * s)479 amrr_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
496 static void
amrr_node_stats(struct ieee80211_node * ni,struct sbuf * s)497 amrr_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