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 #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
64 static void amrr_setinterval(const struct ieee80211vap *, int);
65 static void amrr_init(struct ieee80211vap *);
66 static void amrr_deinit(struct ieee80211vap *);
67 static void amrr_node_init(struct ieee80211_node *);
68 static void amrr_node_deinit(struct ieee80211_node *);
69 static int amrr_update(struct ieee80211_amrr *,
70 struct ieee80211_amrr_node *, struct ieee80211_node *);
71 static int amrr_rate(struct ieee80211_node *, void *, uint32_t);
72 static void amrr_tx_complete(const struct ieee80211vap *,
73 const struct ieee80211_node *, int,
74 void *, void *);
75 static void amrr_tx_update(const struct ieee80211vap *vap,
76 const struct ieee80211_node *, void *, void *, void *);
77 static void amrr_sysctlattach(struct ieee80211vap *,
78 struct sysctl_ctx_list *, struct sysctl_oid *);
79 static void amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s);
80
81 /* number of references from net80211 layer */
82 static int nrefs = 0;
83
84 static 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 };
98 IEEE80211_RATECTL_MODULE(amrr, 1);
99 IEEE80211_RATECTL_ALG(amrr, IEEE80211_RATECTL_AMRR, amrr);
100
101 static void
102 amrr_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
116 static void
117 amrr_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
136 static void
137 amrr_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 */
150 static int
151 amrr_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
163 static void
164 amrr_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
244 static void
245 amrr_node_deinit(struct ieee80211_node *ni)
246 {
247 IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
248 }
249
250 static int
251 amrr_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 */
335 static int
336 amrr_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 */
383 static void
384 amrr_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 */
405 static void
406 amrr_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
420 static int
421 amrr_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
438 static void
439 amrr_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
459 static void
460 amrr_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 }
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