sys/net80211/ieee80211_rssadapt.c

   1 /* $NetBSD: ieee80211_rssadapt.c,v 1.16 2008/11/12 12:36:28 ad Exp $ */
   2 /*-
   3  * Copyright (c) 2003, 2004 David Young.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or
   6  * without modification, are permitted provided that the following
   7  * conditions are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above
  11  *    copyright notice, this list of conditions and the following
  12  *    disclaimer in the documentation and/or other materials provided
  13  *    with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
  16  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  17  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  18  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
  19  * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  21  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  23  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  26  * OF SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 #ifdef __NetBSD__
  31 __KERNEL_RCSID(0, "$NetBSD: ieee80211_rssadapt.c,v 1.16 2008/11/12 12:36:28 ad Exp $");
  32 #endif
  33
  34 #include <sys/param.h>
  35 #include <sys/types.h>
  36 #include <sys/kernel.h>         /* for hz */
  37 #include <sys/sysctl.h>
  38
  39 #include <net/if.h>
  40 #include <net/if_media.h>
  41 #include <net/if_ether.h>
  42
  43 #include <net80211/ieee80211_netbsd.h>
  44 #include <net80211/ieee80211_var.h>
  45 #include <net80211/ieee80211.h>
  46 #include <net80211/ieee80211_rssadapt.h>
  47
  48 #ifdef interpolate
  49 #undef interpolate
  50 #endif
  51 #define interpolate(parm, old, new) ((parm##_old * (old) + \
  52                                      (parm##_denom - parm##_old) * (new)) / \
  53                                     parm##_denom)
  54
  55 #ifdef IEEE80211_DEBUG
  56 static  struct timeval lastrateadapt;   /* time of last rate adaptation msg */
  57 static  int currssadaptps = 0;          /* rate-adaptation msgs this second */
  58 static  int ieee80211_adaptrate = 4;    /* rate-adaptation max msgs/sec */
  59
  60 #define RSSADAPT_DO_PRINT() \
  61         ((ieee80211_rssadapt_debug > 0) && \
  62          ppsratecheck(&lastrateadapt, &currssadaptps, ieee80211_adaptrate))
  63 #define RSSADAPT_PRINTF(X) \
  64         if (RSSADAPT_DO_PRINT()) \
  65                 printf X
  66
  67 int ieee80211_rssadapt_debug = 0;
  68
  69 #else
  70 #define RSSADAPT_DO_PRINT() (0)
  71 #define RSSADAPT_PRINTF(X)
  72 #endif
  73
  74 static struct ieee80211_rssadapt_expavgctl master_expavgctl = {
  75         .rc_decay_denom = 16,
  76         .rc_decay_old = 15,
  77         .rc_thresh_denom = 8,
  78         .rc_thresh_old = 4,
  79         .rc_avgrssi_denom = 8,
  80         .rc_avgrssi_old = 4
  81 };
  82
  83 #ifdef __NetBSD__
  84 #ifdef IEEE80211_DEBUG
  85 /* TBD factor with sysctl_ath_verify, sysctl_ieee80211_verify. */
  86 static int
  87 sysctl_ieee80211_rssadapt_debug(SYSCTLFN_ARGS)
  88 {
  89         int error, t;
  90         struct sysctlnode node;
  91
  92         node = *rnode;
  93         t = *(int*)rnode->sysctl_data;
  94         node.sysctl_data = &t;
  95         error = sysctl_lookup(SYSCTLFN_CALL(&node));
  96         if (error || newp == NULL)
  97                 return (error);
  98
  99         if (t < 0 || t > 2)
 100                 return (EINVAL);
 101         *(int*)rnode->sysctl_data = t;
 102
 103         return (0);
 104 }
 105 #endif /* IEEE80211_DEBUG */
 106
 107 /* TBD factor with sysctl_ath_verify, sysctl_ieee80211_verify. */
 108 static int
 109 sysctl_ieee80211_rssadapt_expavgctl(SYSCTLFN_ARGS)
 110 {
 111         struct ieee80211_rssadapt_expavgctl rc;
 112         int error;
 113         struct sysctlnode node;
 114
 115         node = *rnode;
 116         rc = *(struct ieee80211_rssadapt_expavgctl *)rnode->sysctl_data;
 117         node.sysctl_data = &rc;
 118         error = sysctl_lookup(SYSCTLFN_CALL(&node));
 119         if (error || newp == NULL)
 120                 return (error);
 121
 122         if (/* rc.rc_decay_old < 0 || */
 123             rc.rc_decay_denom < rc.rc_decay_old)
 124                 return (EINVAL);
 125
 126         if (/* rc.rc_thresh_old < 0 || */
 127             rc.rc_thresh_denom < rc.rc_thresh_old)
 128                 return (EINVAL);
 129
 130         if (/* rc.rc_avgrssi_old < 0 || */
 131             rc.rc_avgrssi_denom < rc.rc_avgrssi_old)
 132                 return (EINVAL);
 133
 134         *(struct ieee80211_rssadapt_expavgctl *)rnode->sysctl_data = rc;
 135
 136         return (0);
 137 }
 138
 139 /*
 140  * Setup sysctl(3) MIB, net.ieee80211.*
 141  *
 142  * TBD condition CTLFLAG_PERMANENT on being a module or not
 143  */
 144 SYSCTL_SETUP(sysctl_ieee80211_rssadapt,
 145     "sysctl ieee80211 rssadapt subtree setup")
 146 {
 147         int rc;
 148         const struct sysctlnode *node;
 149
 150         if ((rc = sysctl_createv(clog, 0, NULL, &node,
 151             CTLFLAG_PERMANENT, CTLTYPE_NODE, "net", NULL,
 152             NULL, 0, NULL, 0, CTL_NET, CTL_EOL)) != 0)
 153                 goto err;
 154
 155         if ((rc = sysctl_createv(clog, 0, &node, &node,
 156             CTLFLAG_PERMANENT, CTLTYPE_NODE, "link", NULL,
 157             NULL, 0, NULL, 0, PF_LINK, CTL_EOL)) != 0)
 158                 goto err;
 159
 160         if ((rc = sysctl_createv(clog, 0, &node, &node,
 161             CTLFLAG_PERMANENT, CTLTYPE_NODE, "ieee80211", NULL,
 162             NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL)) != 0)
 163                 goto err;
 164
 165         if ((rc = sysctl_createv(clog, 0, &node, &node,
 166             CTLFLAG_PERMANENT, CTLTYPE_NODE, "rssadapt",
 167             SYSCTL_DESCR("Received Signal Strength adaptation controls"),
 168             NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL)) != 0)
 169                 goto err;
 170
 171 #ifdef IEEE80211_DEBUG
 172         /* control debugging printfs */
 173         if ((rc = sysctl_createv(clog, 0, &node, NULL,
 174             CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "debug",
 175             SYSCTL_DESCR("Enable RSS adaptation debugging output"),
 176             sysctl_ieee80211_rssadapt_debug, 0, &ieee80211_rssadapt_debug, 0,
 177             CTL_CREATE, CTL_EOL)) != 0)
 178                 goto err;
 179 #endif /* IEEE80211_DEBUG */
 180
 181         /* control rate of decay for exponential averages */
 182         if ((rc = sysctl_createv(clog, 0, &node, NULL,
 183             CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_STRUCT,
 184             "expavgctl", SYSCTL_DESCR("RSS exponential averaging control"),
 185             sysctl_ieee80211_rssadapt_expavgctl, 0,
 186             &master_expavgctl, sizeof(master_expavgctl), CTL_CREATE,
 187             CTL_EOL)) != 0)
 188                 goto err;
 189
 190         return;
 191 err:
 192         printf("%s: sysctl_createv failed (rc = %d)\n", __func__, rc);
 193 }
 194 #endif /* __NetBSD__ */
 195
 196 int
 197 ieee80211_rssadapt_choose(struct ieee80211_rssadapt *ra,
 198     struct ieee80211_rateset *rs, struct ieee80211_frame *wh, u_int len,
 199     int fixed_rate, const char *dvname, int do_not_adapt)
 200 {
 201         u_int16_t (*thrs)[IEEE80211_RATE_SIZE];
 202         int flags = 0, i, rateidx = 0, thridx, top;
 203
 204         if ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) == IEEE80211_FC0_TYPE_CTL)
 205                 flags |= IEEE80211_RATE_BASIC;
 206
 207         for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
 208              i < IEEE80211_RSSADAPT_BKTS;
 209              i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
 210                 thridx = i;
 211                 if (len <= top)
 212                         break;
 213         }
 214
 215         thrs = &ra->ra_rate_thresh[thridx];
 216
 217         if (fixed_rate != -1) {
 218                 if ((rs->rs_rates[fixed_rate] & flags) == flags) {
 219                         rateidx = fixed_rate;
 220                         goto out;
 221                 }
 222                 flags |= IEEE80211_RATE_BASIC;
 223                 i = fixed_rate;
 224         } else
 225                 i = rs->rs_nrates;
 226
 227         while (--i >= 0) {
 228                 rateidx = i;
 229                 if ((rs->rs_rates[i] & flags) != flags)
 230                         continue;
 231                 if (do_not_adapt)
 232                         break;
 233                 if ((*thrs)[i] < ra->ra_avg_rssi)
 234                         break;
 235         }
 236
 237 out:
 238 #ifdef IEEE80211_DEBUG
 239         if (ieee80211_rssadapt_debug && dvname != NULL) {
 240                 printf("%s: dst %s threshold[%d, %d.%d] %d < %d\n",
 241                     dvname, ether_sprintf(wh->i_addr1), len,
 242                     (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) / 2,
 243                     (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) * 5 % 10,
 244                     (*thrs)[rateidx], ra->ra_avg_rssi);
 245         }
 246 #endif /* IEEE80211_DEBUG */
 247         return rateidx;
 248 }
 249
 250 void
 251 ieee80211_rssadapt_updatestats(struct ieee80211_rssadapt *ra)
 252 {
 253         long interval;
 254
 255         ra->ra_pktrate =
 256             (ra->ra_pktrate + 10 * (ra->ra_nfail + ra->ra_nok)) / 2;
 257         ra->ra_nfail = ra->ra_nok = 0;
 258
 259         /* a node is eligible for its rate to be raised every 1/10 to 10
 260          * seconds, more eligible in proportion to recent packet rates.
 261          */
 262         interval = MAX(100000, 10000000 / MAX(1, 10 * ra->ra_pktrate));
 263         ra->ra_raise_interval.tv_sec = interval / (1000 * 1000);
 264         ra->ra_raise_interval.tv_usec = interval % (1000 * 1000);
 265 }
 266
 267 void
 268 ieee80211_rssadapt_input(struct ieee80211com *ic, struct ieee80211_node *ni,
 269     struct ieee80211_rssadapt *ra, int rssi)
 270 {
 271 #ifdef IEEE80211_DEBUG
 272         int last_avg_rssi = ra->ra_avg_rssi;
 273 #endif
 274
 275         ra->ra_avg_rssi = interpolate(master_expavgctl.rc_avgrssi,
 276                                       ra->ra_avg_rssi, (rssi << 8));
 277
 278         RSSADAPT_PRINTF(("%s: src %s rssi %d avg %d -> %d\n",
 279             ic->ic_ifp->if_xname, ether_sprintf(ni->ni_macaddr),
 280             rssi, last_avg_rssi, ra->ra_avg_rssi));
 281 }
 282
 283 /*
 284  * Adapt the data rate to suit the conditions.  When a transmitted
 285  * packet is dropped after IEEE80211_RSSADAPT_RETRY_LIMIT retransmissions,
 286  * raise the RSS threshold for transmitting packets of similar length at
 287  * the same data rate.
 288  */
 289 void
 290 ieee80211_rssadapt_lower_rate(struct ieee80211com *ic,
 291     struct ieee80211_node *ni, struct ieee80211_rssadapt *ra,
 292     struct ieee80211_rssdesc *id)
 293 {
 294         struct ieee80211_rateset *rs = &ni->ni_rates;
 295         u_int16_t last_thr;
 296         u_int i, thridx, top;
 297
 298         ra->ra_nfail++;
 299
 300         if (id->id_rateidx >= rs->rs_nrates) {
 301                 RSSADAPT_PRINTF(("ieee80211_rssadapt_lower_rate: "
 302                     "%s rate #%d > #%d out of bounds\n",
 303                     ether_sprintf(ni->ni_macaddr), id->id_rateidx,
 304                         rs->rs_nrates - 1));
 305                 return;
 306         }
 307
 308         for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
 309              i < IEEE80211_RSSADAPT_BKTS;
 310              i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
 311                 thridx = i;
 312                 if (id->id_len <= top)
 313                         break;
 314         }
 315
 316         last_thr = ra->ra_rate_thresh[thridx][id->id_rateidx];
 317         ra->ra_rate_thresh[thridx][id->id_rateidx] =
 318             interpolate(master_expavgctl.rc_thresh, last_thr,
 319                         (id->id_rssi << 8));
 320
 321         RSSADAPT_PRINTF(("%s: dst %s rssi %d threshold[%d, %d.%d] %d -> %d\n",
 322             ic->ic_ifp->if_xname, ether_sprintf(ni->ni_macaddr),
 323             id->id_rssi, id->id_len,
 324             (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) / 2,
 325             (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) * 5 % 10,
 326             last_thr, ra->ra_rate_thresh[thridx][id->id_rateidx]));
 327 }
 328
 329 void
 330 ieee80211_rssadapt_raise_rate(struct ieee80211com *ic,
 331     struct ieee80211_rssadapt *ra, struct ieee80211_rssdesc *id)
 332 {
 333         u_int16_t (*thrs)[IEEE80211_RATE_SIZE], newthr, oldthr;
 334         struct ieee80211_node *ni = id->id_node;
 335         struct ieee80211_rateset *rs = &ni->ni_rates;
 336         int i, rate, top;
 337 #ifdef IEEE80211_DEBUG
 338         int j;
 339 #endif
 340
 341         ra->ra_nok++;
 342
 343         if (!ratecheck(&ra->ra_last_raise, &ra->ra_raise_interval))
 344                 return;
 345
 346         for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
 347              i < IEEE80211_RSSADAPT_BKTS;
 348              i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
 349                 thrs = &ra->ra_rate_thresh[i];
 350                 if (id->id_len <= top)
 351                         break;
 352         }
 353
 354         if (id->id_rateidx + 1 < rs->rs_nrates &&
 355             (*thrs)[id->id_rateidx + 1] > (*thrs)[id->id_rateidx]) {
 356                 rate = (rs->rs_rates[id->id_rateidx + 1] & IEEE80211_RATE_VAL);
 357
 358                 RSSADAPT_PRINTF(("%s: threshold[%d, %d.%d] decay %d ",
 359                     ic->ic_ifp->if_xname,
 360                     IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER* i),
 361                     rate / 2, rate * 5 % 10, (*thrs)[id->id_rateidx + 1]));
 362                 oldthr = (*thrs)[id->id_rateidx + 1];
 363                 if ((*thrs)[id->id_rateidx] == 0)
 364                         newthr = ra->ra_avg_rssi;
 365                 else
 366                         newthr = (*thrs)[id->id_rateidx];
 367                 (*thrs)[id->id_rateidx + 1] =
 368                     interpolate(master_expavgctl.rc_decay, oldthr, newthr);
 369
 370                 RSSADAPT_PRINTF(("-> %d\n", (*thrs)[id->id_rateidx + 1]));
 371         }
 372
 373 #ifdef IEEE80211_DEBUG
 374         if (RSSADAPT_DO_PRINT()) {
 375                 printf("%s: dst %s thresholds\n", ic->ic_ifp->if_xname,
 376                     ether_sprintf(ni->ni_macaddr));
 377                 for (i = 0; i < IEEE80211_RSSADAPT_BKTS; i++) {
 378                         printf("%d-byte", IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER * i));
 379                         for (j = 0; j < rs->rs_nrates; j++) {
 380                                 rate = (rs->rs_rates[j] & IEEE80211_RATE_VAL);
 381                                 printf(", T[%d.%d] = %d", rate / 2,
 382                                     rate * 5 % 10, ra->ra_rate_thresh[i][j]);
 383                         }
 384                         printf("\n");
 385                 }
 386         }
 387 #endif /* IEEE80211_DEBUG */
 388 }