target/linux/package/ieee80211-dscape/src/rate_control.c

   1 /*
   2  * Copyright 2002-2005, Instant802 Networks, Inc.
   3  * Copyright 2005, Devicescape Software, Inc.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/config.h>
  11 #include <linux/version.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/netdevice.h>
  15 #include <linux/types.h>
  16 #include <linux/slab.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/compiler.h>
  19
  20 #include <net/ieee80211.h>
  21 #include "ieee80211_i.h"
  22 #include "rate_control.h"
  23
  24
  25 /* This is a minimal implementation of TX rate controlling that can be used
  26  * as the default when no improved mechanisms are available. */
  27
  28
  29 #define RATE_CONTROL_EMERG_DEC 2
  30 #define RATE_CONTROL_INTERVAL (HZ / 20)
  31 #define RATE_CONTROL_MIN_TX 10
  32
  33
  34 static void rate_control_rate_inc(struct ieee80211_local *local,
  35                                   struct sta_info *sta)
  36 {
  37         struct ieee80211_sub_if_data *sdata;
  38         int i = sta->txrate;
  39         int maxrate;
  40
  41         sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
  42         if (sdata->bss && sdata->bss->force_unicast_rateidx > -1) {
  43                 /* forced unicast rate - do not change STA rate */
  44                 return;
  45         }
  46
  47         maxrate = sdata->bss ? sdata->bss->max_ratectrl_rateidx : -1;
  48
  49         if (i > local->num_curr_rates)
  50                 i = local->num_curr_rates - 2;
  51
  52         while (i + 1 < local->num_curr_rates) {
  53                 i++;
  54                 if (sta->supp_rates & BIT(i) &&
  55                     local->curr_rates[i].flags & IEEE80211_RATE_SUPPORTED &&
  56                     (maxrate < 0 || i <= maxrate)) {
  57                         sta->txrate = i;
  58                         break;
  59                 }
  60         }
  61 }
  62
  63
  64 static void rate_control_rate_dec(struct ieee80211_local *local,
  65                                   struct sta_info *sta)
  66 {
  67         struct ieee80211_sub_if_data *sdata;
  68         int i = sta->txrate;
  69
  70         sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
  71         if (sdata->bss && sdata->bss->force_unicast_rateidx > -1) {
  72                 /* forced unicast rate - do not change STA rate */
  73                 return;
  74         }
  75
  76         if (i > local->num_curr_rates)
  77                 i = local->num_curr_rates;
  78
  79         while (i > 0) {
  80                 i--;
  81                 if (sta->supp_rates & BIT(i) &&
  82                     local->curr_rates[i].flags & IEEE80211_RATE_SUPPORTED) {
  83                         sta->txrate = i;
  84                         break;
  85                 }
  86         }
  87 }
  88
  89
  90 static struct ieee80211_rate *
  91 rate_control_lowest_rate(struct ieee80211_local *local)
  92 {
  93         int i;
  94
  95         for (i = 0; i < local->num_curr_rates; i++) {
  96                 struct ieee80211_rate *rate = &local->curr_rates[i];
  97
  98                 if (rate->flags & IEEE80211_RATE_SUPPORTED
  99                         )
 100                         return rate;
 101         }
 102
 103         printk(KERN_DEBUG "rate_control_lowest_rate - no supported rates "
 104                "found\n");
 105         return &local->curr_rates[0];
 106 }
 107
 108
 109 struct global_rate_control {
 110         int dummy;
 111 };
 112
 113 struct sta_rate_control {
 114         unsigned long last_rate_change;
 115         u32 tx_num_failures;
 116         u32 tx_num_xmit;
 117
 118         unsigned long avg_rate_update;
 119         u32 tx_avg_rate_sum;
 120         u32 tx_avg_rate_num;
 121 };
 122
 123
 124 static void rate_control_simple_tx_status(struct net_device *dev,
 125                                           struct sk_buff *skb,
 126                                           struct ieee80211_tx_status *status)
 127 {
 128         struct ieee80211_local *local = dev->priv;
 129         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 130         struct sta_info *sta;
 131         struct sta_rate_control *srctrl;
 132
 133         sta = sta_info_get(local, hdr->addr1);
 134
 135         if (!sta)
 136             return;
 137
 138         srctrl = sta->rate_ctrl_priv;
 139         srctrl->tx_num_xmit++;
 140         if (status->excessive_retries) {
 141                 sta->antenna_sel = sta->antenna_sel == 1 ? 2 : 1;
 142                 if (local->sta_antenna_sel == STA_ANTENNA_SEL_SW_CTRL_DEBUG) {
 143                         printk(KERN_DEBUG "%s: " MACSTR " TX antenna --> %d "
 144                                "(@%lu)\n",
 145                                dev->name, MAC2STR(hdr->addr1),
 146                                sta->antenna_sel, jiffies);
 147                 }
 148                 srctrl->tx_num_failures++;
 149                 sta->tx_retry_failed++;
 150                 sta->tx_num_consecutive_failures++;
 151                 sta->tx_num_mpdu_fail++;
 152         } else {
 153                 sta->last_ack_rssi[0] = sta->last_ack_rssi[1];
 154                 sta->last_ack_rssi[1] = sta->last_ack_rssi[2];
 155                 sta->last_ack_rssi[2] = status->ack_signal;
 156                 sta->tx_num_consecutive_failures = 0;
 157                 sta->tx_num_mpdu_ok++;
 158         }
 159         sta->tx_retry_count += status->retry_count;
 160         sta->tx_num_mpdu_fail += status->retry_count;
 161
 162         if (time_after(jiffies,
 163                        srctrl->last_rate_change + RATE_CONTROL_INTERVAL) &&
 164                 srctrl->tx_num_xmit > RATE_CONTROL_MIN_TX) {
 165                 u32 per_failed;
 166                 srctrl->last_rate_change = jiffies;
 167
 168                 per_failed = (100 * sta->tx_num_mpdu_fail) /
 169                         (sta->tx_num_mpdu_fail + sta->tx_num_mpdu_ok);
 170                 /* TODO: calculate average per_failed to make adjusting
 171                  * parameters easier */
 172 #if 0
 173                 if (net_ratelimit()) {
 174                         printk(KERN_DEBUG "MPDU fail=%d ok=%d per_failed=%d\n",
 175                                sta->tx_num_mpdu_fail, sta->tx_num_mpdu_ok,
 176                                per_failed);
 177                 }
 178 #endif
 179
 180                 if (per_failed > local->rate_ctrl_num_down) {
 181                         rate_control_rate_dec(local, sta);
 182                 } else if (per_failed < local->rate_ctrl_num_up) {
 183                         rate_control_rate_inc(local, sta);
 184                 }
 185                 srctrl->tx_avg_rate_sum += local->curr_rates[sta->txrate].rate;
 186                 srctrl->tx_avg_rate_num++;
 187                 srctrl->tx_num_failures = 0;
 188                 srctrl->tx_num_xmit = 0;
 189         } else if (sta->tx_num_consecutive_failures >=
 190                    RATE_CONTROL_EMERG_DEC) {
 191                 rate_control_rate_dec(local, sta);
 192         }
 193
 194         if (srctrl->avg_rate_update + 60 * HZ < jiffies) {
 195                 srctrl->avg_rate_update = jiffies;
 196                 if (srctrl->tx_avg_rate_num > 0) {
 197 #ifdef CONFIG_IEEE80211_VERBOSE_DEBUG
 198                         printk(KERN_DEBUG "%s: STA " MACSTR " Average rate: "
 199                                "%d (%d/%d)\n",
 200                                dev->name, MAC2STR(sta->addr),
 201                                srctrl->tx_avg_rate_sum /
 202                                srctrl->tx_avg_rate_num,
 203                                srctrl->tx_avg_rate_sum,
 204                                srctrl->tx_avg_rate_num);
 205 #endif /* CONFIG_IEEE80211_VERBOSE_DEBUG */
 206                         srctrl->tx_avg_rate_sum = 0;
 207                         srctrl->tx_avg_rate_num = 0;
 208                 }
 209         }
 210
 211         sta_info_release(local, sta);
 212 }
 213
 214
 215 static struct ieee80211_rate *
 216 rate_control_simple_get_rate(struct net_device *dev, struct sk_buff *skb,
 217                              struct rate_control_extra *extra)
 218 {
 219         struct ieee80211_local *local = dev->priv;
 220         struct ieee80211_sub_if_data *sdata;
 221         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 222         struct sta_info *sta;
 223         int rateidx, nonerp_idx;
 224         u16 fc;
 225
 226         memset(extra, 0, sizeof(*extra));
 227
 228         fc = le16_to_cpu(hdr->frame_control);
 229         if (WLAN_FC_GET_TYPE(fc) != WLAN_FC_TYPE_DATA ||
 230             (hdr->addr1[0] & 0x01)) {
 231                 /* Send management frames and broadcast/multicast data using
 232                  * lowest rate. */
 233                 /* TODO: this could probably be improved.. */
 234                 return rate_control_lowest_rate(local);
 235         }
 236
 237         sta = sta_info_get(local, hdr->addr1);
 238
 239         if (!sta)
 240                 return rate_control_lowest_rate(local);
 241
 242         sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 243         if (sdata->bss && sdata->bss->force_unicast_rateidx > -1)
 244                 sta->txrate = sdata->bss->force_unicast_rateidx;
 245
 246         rateidx = sta->txrate;
 247
 248         if (rateidx >= local->num_curr_rates)
 249                 rateidx = local->num_curr_rates - 1;
 250
 251         sta->last_txrate = rateidx;
 252         nonerp_idx = rateidx;
 253         while (nonerp_idx > 0 &&
 254                ((local->curr_rates[nonerp_idx].flags & IEEE80211_RATE_ERP) ||
 255                 !(local->curr_rates[nonerp_idx].flags &
 256                   IEEE80211_RATE_SUPPORTED) ||
 257                 !(sta->supp_rates & BIT(nonerp_idx))))
 258                 nonerp_idx--;
 259         extra->nonerp_idx = nonerp_idx;
 260         extra->nonerp = &local->curr_rates[extra->nonerp_idx];
 261
 262         sta_info_release(local, sta);
 263
 264         return &local->curr_rates[rateidx];
 265 }
 266
 267
 268 static void rate_control_simple_rate_init(struct ieee80211_local *local,
 269                                           struct sta_info *sta)
 270 {
 271         int i;
 272         sta->txrate = 0;
 273         /* TODO: what is a good starting rate for STA? About middle? Maybe not
 274          * the lowest or the highest rate.. Could consider using RSSI from
 275          * previous packets? Need to have IEEE 802.1X auth succeed immediately
 276          * after assoc.. */
 277         for (i = 0; i < local->num_curr_rates; i++) {
 278                 if ((sta->supp_rates & BIT(i)) &&
 279                     (local->curr_rates[i].flags & IEEE80211_RATE_SUPPORTED))
 280                         sta->txrate = i;
 281         }
 282 }
 283
 284
 285 static void * rate_control_simple_alloc(struct ieee80211_local *local)
 286 {
 287         struct global_rate_control *rctrl;
 288
 289         rctrl = kmalloc(sizeof(*rctrl), GFP_ATOMIC);
 290         if (rctrl == NULL) {
 291                 return NULL;
 292         }
 293         memset(rctrl, 0, sizeof(*rctrl));
 294         return rctrl;
 295 }
 296
 297
 298 static void rate_control_simple_free(void *priv)
 299 {
 300         struct global_rate_control *rctrl = priv;
 301         kfree(rctrl);
 302 }
 303
 304
 305 static void rate_control_simple_clear(void *priv)
 306 {
 307 }
 308
 309
 310 static void * rate_control_simple_alloc_sta(void)
 311 {
 312         struct sta_rate_control *rctrl;
 313
 314         rctrl = kmalloc(sizeof(*rctrl), GFP_ATOMIC);
 315         if (rctrl == NULL) {
 316                 return NULL;
 317         }
 318         memset(rctrl, 0, sizeof(*rctrl));
 319         return rctrl;
 320 }
 321
 322
 323 static void rate_control_simple_free_sta(void *priv)
 324 {
 325         struct sta_rate_control *rctrl = priv;
 326         kfree(rctrl);
 327 }
 328
 329
 330 static int rate_control_simple_status_sta(struct ieee80211_local *local,
 331                                           struct sta_info *sta, char *buf)
 332 {
 333         char *p = buf;
 334         struct sta_rate_control *srctrl = sta->rate_ctrl_priv;
 335
 336         p += sprintf(p, "tx_avg_rate_sum=%d\n", srctrl->tx_avg_rate_sum);
 337         p += sprintf(p, "tx_avg_rate_num=%d\n", srctrl->tx_avg_rate_num);
 338         if (srctrl->tx_avg_rate_num)
 339                 p += sprintf(p, "tx_avg_rate_avg=%d\n",
 340                              srctrl->tx_avg_rate_sum /
 341                              srctrl->tx_avg_rate_num);
 342         return p - buf;
 343 }
 344
 345
 346 static int rate_control_simple_status_global(struct ieee80211_local *local,
 347                                              char *buf)
 348 {
 349         return 0;
 350 }
 351
 352
 353 static struct rate_control_ops rate_control_simple = {
 354         .name = "simple",
 355         .tx_status = rate_control_simple_tx_status,
 356         .get_rate = rate_control_simple_get_rate,
 357         .rate_init = rate_control_simple_rate_init,
 358         .clear = rate_control_simple_clear,
 359         .status_sta = rate_control_simple_status_sta,
 360         .status_global = rate_control_simple_status_global,
 361         .alloc = rate_control_simple_alloc,
 362         .free = rate_control_simple_free,
 363         .alloc_sta = rate_control_simple_alloc_sta,
 364         .free_sta = rate_control_simple_free_sta,
 365 };
 366
 367
 368 int __init rate_control_simple_init(void)
 369 {
 370         return ieee80211_rate_control_register(&rate_control_simple);
 371 }
 372
 373
 374 static void __exit rate_control_simple_exit(void)
 375 {
 376         ieee80211_rate_control_unregister(&rate_control_simple);
 377 }
 378
 379
 380 module_init(rate_control_simple_init);
 381 module_exit(rate_control_simple_exit);