sys/netproto/802_11/wlan/ieee80211_amrr.c

   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 }