sys/netproto/802_11/wlan/ieee80211_rssadapt.c

   1 /*      $FreeBSD$       */
   2 /* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */
   3 /*-
   4  * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org>
   5  * Copyright (c) 2003, 2004 David Young.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or
   8  * without modification, are permitted provided that the following
   9  * conditions are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above
  13  *    copyright notice, this list of conditions and the following
  14  *    disclaimer in the documentation and/or other materials provided
  15  *    with the distribution.
  16  * 3. The name of David Young may not be used to endorse or promote
  17  *    products derived from this software without specific prior
  18  *    written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
  21  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  22  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  23  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
  24  * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  26  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  28  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  31  * OF SUCH DAMAGE.
  32  */
  33 #include "opt_wlan.h"
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/kernel.h>
  38 #include <sys/malloc.h>
  39 #include <sys/module.h>
  40 #include <sys/socket.h>
  41 #include <sys/sysctl.h>
  42
  43 #include <net/if.h>
  44 #include <net/if_var.h>
  45 #include <net/if_media.h>
  46 #include <net/ethernet.h>
  47
  48 #include <netproto/802_11/ieee80211_var.h>
  49 #include <netproto/802_11/ieee80211_rssadapt.h>
  50 #include <netproto/802_11/ieee80211_ratectl.h>
  51
  52 struct rssadapt_expavgctl {
  53         /* RSS threshold decay. */
  54         u_int rc_decay_denom;
  55         u_int rc_decay_old;
  56         /* RSS threshold update. */
  57         u_int rc_thresh_denom;
  58         u_int rc_thresh_old;
  59         /* RSS average update. */
  60         u_int rc_avgrssi_denom;
  61         u_int rc_avgrssi_old;
  62 };
  63
  64 static struct rssadapt_expavgctl master_expavgctl = {
  65         .rc_decay_denom = 16,
  66         .rc_decay_old = 15,
  67         .rc_thresh_denom = 8,
  68         .rc_thresh_old = 4,
  69         .rc_avgrssi_denom = 8,
  70         .rc_avgrssi_old = 4
  71 };
  72
  73 #ifdef interpolate
  74 #undef interpolate
  75 #endif
  76 #define interpolate(parm, old, new) ((parm##_old * (old) + \
  77                                      (parm##_denom - parm##_old) * (new)) / \
  78                                     parm##_denom)
  79
  80 static void     rssadapt_setinterval(const struct ieee80211vap *, int);
  81 static void     rssadapt_init(struct ieee80211vap *);
  82 static void     rssadapt_deinit(struct ieee80211vap *);
  83 static void     rssadapt_updatestats(struct ieee80211_rssadapt_node *);
  84 static void     rssadapt_node_init(struct ieee80211_node *);
  85 static void     rssadapt_node_deinit(struct ieee80211_node *);
  86 static int      rssadapt_rate(struct ieee80211_node *, void *, uint32_t);
  87 static void     rssadapt_lower_rate(struct ieee80211_rssadapt_node *, int, int);
  88 static void     rssadapt_raise_rate(struct ieee80211_rssadapt_node *,
  89                         int, int);
  90 static void     rssadapt_tx_complete(const struct ieee80211vap *,
  91                         const struct ieee80211_node *, int,
  92                         void *, void *);
  93 static void     rssadapt_sysctlattach(struct ieee80211vap *,
  94                         struct sysctl_ctx_list *, struct sysctl_oid *);
  95
  96 /* number of references from net80211 layer */
  97 static  int nrefs = 0;
  98
  99 static const struct ieee80211_ratectl rssadapt = {
 100         .ir_name        = "rssadapt",
 101         .ir_attach      = NULL,
 102         .ir_detach      = NULL,
 103         .ir_init        = rssadapt_init,
 104         .ir_deinit      = rssadapt_deinit,
 105         .ir_node_init   = rssadapt_node_init,
 106         .ir_node_deinit = rssadapt_node_deinit,
 107         .ir_rate        = rssadapt_rate,
 108         .ir_tx_complete = rssadapt_tx_complete,
 109         .ir_tx_update   = NULL,
 110         .ir_setinterval = rssadapt_setinterval,
 111 };
 112 IEEE80211_RATECTL_MODULE(rssadapt, 1);
 113 IEEE80211_RATECTL_ALG(rssadapt, IEEE80211_RATECTL_RSSADAPT, rssadapt);
 114
 115 static void
 116 rssadapt_setinterval(const struct ieee80211vap *vap, int msecs)
 117 {
 118         struct ieee80211_rssadapt *rs = vap->iv_rs;
 119         int t;
 120
 121         if (msecs < 100)
 122                 msecs = 100;
 123         t = msecs_to_ticks(msecs);
 124         rs->interval = (t < 1) ? 1 : t;
 125 }
 126
 127 static void
 128 rssadapt_init(struct ieee80211vap *vap)
 129 {
 130         struct ieee80211_rssadapt *rs;
 131
 132         KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
 133             __func__));
 134
 135 #if defined(__DragonFly__)
 136         vap->iv_rs = rs = kmalloc(sizeof(struct ieee80211_rssadapt),
 137             M_80211_RATECTL, M_INTWAIT|M_ZERO);
 138 #else
 139         vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt),
 140             M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
 141 #endif
 142         if (rs == NULL) {
 143                 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
 144                 return;
 145         }
 146         rs->vap = vap;
 147         rssadapt_setinterval(vap, 500 /* msecs */);
 148         rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
 149 }
 150
 151 static void
 152 rssadapt_deinit(struct ieee80211vap *vap)
 153 {
 154         IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
 155 }
 156
 157 static void
 158 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
 159 {
 160         long interval;
 161
 162         ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
 163         ra->ra_nfail = ra->ra_nok = 0;
 164
 165         /*
 166          * A node is eligible for its rate to be raised every 1/10 to 10
 167          * seconds, more eligible in proportion to recent packet rates.
 168          */
 169         interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
 170         ra->ra_raise_interval = msecs_to_ticks(interval);
 171 }
 172
 173 static void
 174 rssadapt_node_init(struct ieee80211_node *ni)
 175 {
 176         struct ieee80211_rssadapt_node *ra;
 177         struct ieee80211vap *vap = ni->ni_vap;
 178         struct ieee80211_rssadapt *rsa = vap->iv_rs;
 179         const struct ieee80211_rateset *rs = &ni->ni_rates;
 180
 181         if (ni->ni_rctls == NULL) {
 182                 ni->ni_rctls = ra =
 183 #if defined(__DragonFly__)
 184                     kmalloc(sizeof(struct ieee80211_rssadapt_node),
 185                         M_80211_RATECTL, M_INTWAIT|M_ZERO);
 186 #else
 187                     IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node),
 188                         M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
 189 #endif
 190                 if (ra == NULL) {
 191                         if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
 192                             "structure\n");
 193                         return;
 194                 }
 195         } else
 196                 ra = ni->ni_rctls;
 197         ra->ra_rs = rsa;
 198         ra->ra_rates = *rs;
 199         rssadapt_updatestats(ra);
 200
 201         /* pick initial rate */
 202         for (ra->ra_rix = rs->rs_nrates - 1;
 203              ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
 204              ra->ra_rix--)
 205                 ;
 206         ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
 207         ra->ra_ticks = ticks;
 208
 209         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
 210             "RSSADAPT initial rate %d", ni->ni_txrate);
 211 }
 212
 213 static void
 214 rssadapt_node_deinit(struct ieee80211_node *ni)
 215 {
 216
 217         IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
 218 }
 219
 220 static __inline int
 221 bucket(int pktlen)
 222 {
 223         int i, top, thridx;
 224
 225         for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
 226              i < IEEE80211_RSSADAPT_BKTS;
 227              i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
 228                 thridx = i;
 229                 if (pktlen <= top)
 230                         break;
 231         }
 232         return thridx;
 233 }
 234
 235 static int
 236 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
 237 {
 238         struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
 239         u_int pktlen = iarg;
 240         const struct ieee80211_rateset *rs = &ra->ra_rates;
 241         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
 242         int rix, rssi;
 243
 244         if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
 245                 rssadapt_updatestats(ra);
 246                 ra->ra_ticks = ticks;
 247         }
 248
 249         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
 250
 251         /* XXX this is average rssi, should be using last value */
 252         rssi = ni->ni_ic->ic_node_getrssi(ni);
 253         for (rix = rs->rs_nrates-1; rix >= 0; rix--)
 254                 if ((*thrs)[rix] < (rssi << 8))
 255                         break;
 256         if (rix != ra->ra_rix) {
 257                 /* update public rate */
 258                 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
 259                 ra->ra_rix = rix;
 260
 261                 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
 262                     "RSSADAPT new rate %d (pktlen %d rssi %d)",
 263                     ni->ni_txrate, pktlen, rssi);
 264         }
 265         return rix;
 266 }
 267
 268 /*
 269  * Adapt the data rate to suit the conditions.  When a transmitted
 270  * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
 271  * raise the RSS threshold for transmitting packets of similar length at
 272  * the same data rate.
 273  */
 274 static void
 275 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
 276 {
 277         uint16_t last_thr;
 278         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
 279         u_int rix;
 280
 281         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
 282
 283         rix = ra->ra_rix;
 284         last_thr = (*thrs)[rix];
 285         (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
 286             last_thr, (rssi << 8));
 287
 288         IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
 289             "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
 290             ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
 291             last_thr, (*thrs)[rix], rssi);
 292 }
 293
 294 static void
 295 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
 296 {
 297         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
 298         uint16_t newthr, oldthr;
 299         int rix;
 300
 301         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
 302
 303         rix = ra->ra_rix;
 304         if ((*thrs)[rix + 1] > (*thrs)[rix]) {
 305                 oldthr = (*thrs)[rix + 1];
 306                 if ((*thrs)[rix] == 0)
 307                         newthr = (rssi << 8);
 308                 else
 309                         newthr = (*thrs)[rix];
 310                 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
 311                     oldthr, newthr);
 312
 313                 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
 314                     "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
 315                     ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
 316                     oldthr, newthr, rssi);
 317
 318                 ra->ra_last_raise = ticks;
 319         }
 320 }
 321
 322 static void
 323 rssadapt_tx_complete(const struct ieee80211vap *vap,
 324     const struct ieee80211_node *ni, int success, void *arg1, void *arg2)
 325 {
 326         struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
 327         int pktlen = *(int *)arg1, rssi = *(int *)arg2;
 328
 329         if (success) {
 330                 ra->ra_nok++;
 331                 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
 332                     (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
 333                         rssadapt_raise_rate(ra, pktlen, rssi);
 334         } else {
 335                 ra->ra_nfail++;
 336                 rssadapt_lower_rate(ra, pktlen, rssi);
 337         }
 338 }
 339
 340 static int
 341 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
 342 {
 343         struct ieee80211vap *vap = arg1;
 344         struct ieee80211_rssadapt *rs = vap->iv_rs;
 345         int msecs = ticks_to_msecs(rs->interval);
 346         int error;
 347
 348         error = sysctl_handle_int(oidp, &msecs, 0, req);
 349         if (error || !req->newptr)
 350                 return error;
 351         rssadapt_setinterval(vap, msecs);
 352         return 0;
 353 }
 354
 355 static void
 356 rssadapt_sysctlattach(struct ieee80211vap *vap,
 357     struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
 358 {
 359
 360         SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
 361             "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
 362             0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
 363 }