net/mac80211/rc80211_simple.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/module.h>
  11 #include <linux/init.h>
  12 #include <linux/netdevice.h>
  13 #include <linux/types.h>
  14 #include <linux/slab.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/compiler.h>
  17
  18 #include <net/mac80211.h>
  19 #include "ieee80211_i.h"
  20 #include "ieee80211_rate.h"
  21 #include "debugfs.h"
  22
  23
  24 /* This is a minimal implementation of TX rate controlling that can be used
  25  * as the default when no improved mechanisms are available. */
  26
  27
  28 #define RATE_CONTROL_EMERG_DEC 2
  29 #define RATE_CONTROL_INTERVAL (HZ / 20)
  30 #define RATE_CONTROL_MIN_TX 10
  31
  32 MODULE_ALIAS("rc80211_default");
  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         struct ieee80211_hw_mode *mode;
  39         int i = sta->txrate;
  40         int maxrate;
  41
  42         sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
  43         if (sdata->bss && sdata->bss->force_unicast_rateidx > -1) {
  44                 /* forced unicast rate - do not change STA rate */
  45                 return;
  46         }
  47
  48         mode = local->oper_hw_mode;
  49         maxrate = sdata->bss ? sdata->bss->max_ratectrl_rateidx : -1;
  50
  51         if (i > mode->num_rates)
  52                 i = mode->num_rates - 2;
  53
  54         while (i + 1 < mode->num_rates) {
  55                 i++;
  56                 if (sta->supp_rates & BIT(i) &&
  57                     mode->rates[i].flags & IEEE80211_RATE_SUPPORTED &&
  58                     (maxrate < 0 || i <= maxrate)) {
  59                         sta->txrate = i;
  60                         break;
  61                 }
  62         }
  63 }
  64
  65
  66 static void rate_control_rate_dec(struct ieee80211_local *local,
  67                                   struct sta_info *sta)
  68 {
  69         struct ieee80211_sub_if_data *sdata;
  70         struct ieee80211_hw_mode *mode;
  71         int i = sta->txrate;
  72
  73         sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
  74         if (sdata->bss && sdata->bss->force_unicast_rateidx > -1) {
  75                 /* forced unicast rate - do not change STA rate */
  76                 return;
  77         }
  78
  79         mode = local->oper_hw_mode;
  80         if (i > mode->num_rates)
  81                 i = mode->num_rates;
  82
  83         while (i > 0) {
  84                 i--;
  85                 if (sta->supp_rates & BIT(i) &&
  86                     mode->rates[i].flags & IEEE80211_RATE_SUPPORTED) {
  87                         sta->txrate = i;
  88                         break;
  89                 }
  90         }
  91 }
  92
  93
  94 static struct ieee80211_rate *
  95 rate_control_lowest_rate(struct ieee80211_local *local,
  96                          struct ieee80211_hw_mode *mode)
  97 {
  98         int i;
  99
 100         for (i = 0; i < mode->num_rates; i++) {
 101                 struct ieee80211_rate *rate = &mode->rates[i];
 102
 103                 if (rate->flags & IEEE80211_RATE_SUPPORTED)
 104                         return rate;
 105         }
 106
 107         printk(KERN_DEBUG "rate_control_lowest_rate - no supported rates "
 108                "found\n");
 109         return &mode->rates[0];
 110 }
 111
 112
 113 struct global_rate_control {
 114         int dummy;
 115 };
 116
 117 struct sta_rate_control {
 118         unsigned long last_rate_change;
 119         u32 tx_num_failures;
 120         u32 tx_num_xmit;
 121
 122         unsigned long avg_rate_update;
 123         u32 tx_avg_rate_sum;
 124         u32 tx_avg_rate_num;
 125
 126 #ifdef CONFIG_MAC80211_DEBUGFS
 127         struct dentry *tx_avg_rate_sum_dentry;
 128         struct dentry *tx_avg_rate_num_dentry;
 129 #endif
 130 };
 131
 132
 133 static void rate_control_simple_tx_status(void *priv, struct net_device *dev,
 134                                           struct sk_buff *skb,
 135                                           struct ieee80211_tx_status *status)
 136 {
 137         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 138         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 139         struct sta_info *sta;
 140         struct sta_rate_control *srctrl;
 141
 142         sta = sta_info_get(local, hdr->addr1);
 143
 144         if (!sta)
 145             return;
 146
 147         srctrl = sta->rate_ctrl_priv;
 148         srctrl->tx_num_xmit++;
 149         if (status->excessive_retries) {
 150                 srctrl->tx_num_failures++;
 151                 sta->tx_retry_failed++;
 152                 sta->tx_num_consecutive_failures++;
 153                 sta->tx_num_mpdu_fail++;
 154         } else {
 155                 sta->last_ack_rssi[0] = sta->last_ack_rssi[1];
 156                 sta->last_ack_rssi[1] = sta->last_ack_rssi[2];
 157                 sta->last_ack_rssi[2] = status->ack_signal;
 158                 sta->tx_num_consecutive_failures = 0;
 159                 sta->tx_num_mpdu_ok++;
 160         }
 161         sta->tx_retry_count += status->retry_count;
 162         sta->tx_num_mpdu_fail += status->retry_count;
 163
 164         if (time_after(jiffies,
 165                        srctrl->last_rate_change + RATE_CONTROL_INTERVAL) &&
 166                 srctrl->tx_num_xmit > RATE_CONTROL_MIN_TX) {
 167                 u32 per_failed;
 168                 srctrl->last_rate_change = jiffies;
 169
 170                 per_failed = (100 * sta->tx_num_mpdu_fail) /
 171                         (sta->tx_num_mpdu_fail + sta->tx_num_mpdu_ok);
 172                 /* TODO: calculate average per_failed to make adjusting
 173                  * parameters easier */
 174 #if 0
 175                 if (net_ratelimit()) {
 176                         printk(KERN_DEBUG "MPDU fail=%d ok=%d per_failed=%d\n",
 177                                sta->tx_num_mpdu_fail, sta->tx_num_mpdu_ok,
 178                                per_failed);
 179                 }
 180 #endif
 181
 182                 /*
 183                  * XXX: Make these configurable once we have an
 184                  * interface to the rate control algorithms
 185                  */
 186                 if (per_failed > RATE_CONTROL_NUM_DOWN) {
 187                         rate_control_rate_dec(local, sta);
 188                 } else if (per_failed < RATE_CONTROL_NUM_UP) {
 189                         rate_control_rate_inc(local, sta);
 190                 }
 191                 srctrl->tx_avg_rate_sum += status->control.rate->rate;
 192                 srctrl->tx_avg_rate_num++;
 193                 srctrl->tx_num_failures = 0;
 194                 srctrl->tx_num_xmit = 0;
 195         } else if (sta->tx_num_consecutive_failures >=
 196                    RATE_CONTROL_EMERG_DEC) {
 197                 rate_control_rate_dec(local, sta);
 198         }
 199
 200         if (srctrl->avg_rate_update + 60 * HZ < jiffies) {
 201                 srctrl->avg_rate_update = jiffies;
 202                 if (srctrl->tx_avg_rate_num > 0) {
 203 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 204                         DECLARE_MAC_BUF(mac);
 205                         printk(KERN_DEBUG "%s: STA %s Average rate: "
 206                                "%d (%d/%d)\n",
 207                                dev->name, print_mac(mac, sta->addr),
 208                                srctrl->tx_avg_rate_sum /
 209                                srctrl->tx_avg_rate_num,
 210                                srctrl->tx_avg_rate_sum,
 211                                srctrl->tx_avg_rate_num);
 212 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
 213                         srctrl->tx_avg_rate_sum = 0;
 214                         srctrl->tx_avg_rate_num = 0;
 215                 }
 216         }
 217
 218         sta_info_put(sta);
 219 }
 220
 221
 222 static struct ieee80211_rate *
 223 rate_control_simple_get_rate(void *priv, struct net_device *dev,
 224                              struct sk_buff *skb,
 225                              struct rate_control_extra *extra)
 226 {
 227         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 228         struct ieee80211_sub_if_data *sdata;
 229         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 230         struct ieee80211_hw_mode *mode = extra->mode;
 231         struct sta_info *sta;
 232         int rateidx, nonerp_idx;
 233         u16 fc;
 234
 235         memset(extra, 0, sizeof(*extra));
 236
 237         fc = le16_to_cpu(hdr->frame_control);
 238         if ((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
 239             (hdr->addr1[0] & 0x01)) {
 240                 /* Send management frames and broadcast/multicast data using
 241                  * lowest rate. */
 242                 /* TODO: this could probably be improved.. */
 243                 return rate_control_lowest_rate(local, mode);
 244         }
 245
 246         sta = sta_info_get(local, hdr->addr1);
 247
 248         if (!sta)
 249                 return rate_control_lowest_rate(local, mode);
 250
 251         sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 252         if (sdata->bss && sdata->bss->force_unicast_rateidx > -1)
 253                 sta->txrate = sdata->bss->force_unicast_rateidx;
 254
 255         rateidx = sta->txrate;
 256
 257         if (rateidx >= mode->num_rates)
 258                 rateidx = mode->num_rates - 1;
 259
 260         sta->last_txrate = rateidx;
 261         nonerp_idx = rateidx;
 262         while (nonerp_idx > 0 &&
 263                ((mode->rates[nonerp_idx].flags & IEEE80211_RATE_ERP) ||
 264                 !(mode->rates[nonerp_idx].flags & IEEE80211_RATE_SUPPORTED) ||
 265                 !(sta->supp_rates & BIT(nonerp_idx))))
 266                 nonerp_idx--;
 267         extra->nonerp = &mode->rates[nonerp_idx];
 268
 269         sta_info_put(sta);
 270
 271         return &mode->rates[rateidx];
 272 }
 273
 274
 275 static void rate_control_simple_rate_init(void *priv, void *priv_sta,
 276                                           struct ieee80211_local *local,
 277                                           struct sta_info *sta)
 278 {
 279         struct ieee80211_hw_mode *mode;
 280         int i;
 281         sta->txrate = 0;
 282         mode = local->oper_hw_mode;
 283         /* TODO: This routine should consider using RSSI from previous packets
 284          * as we need to have IEEE 802.1X auth succeed immediately after assoc..
 285          * Until that method is implemented, we will use the lowest supported rate
 286          * as a workaround, */
 287         for (i = 0; i < mode->num_rates; i++) {
 288                 if ((sta->supp_rates & BIT(i)) &&
 289                     (mode->rates[i].flags & IEEE80211_RATE_SUPPORTED)) {
 290                         sta->txrate = i;
 291                         break;
 292                 }
 293         }
 294 }
 295
 296
 297 static void * rate_control_simple_alloc(struct ieee80211_local *local)
 298 {
 299         struct global_rate_control *rctrl;
 300
 301         rctrl = kzalloc(sizeof(*rctrl), GFP_ATOMIC);
 302
 303         return rctrl;
 304 }
 305
 306
 307 static void rate_control_simple_free(void *priv)
 308 {
 309         struct global_rate_control *rctrl = priv;
 310         kfree(rctrl);
 311 }
 312
 313
 314 static void rate_control_simple_clear(void *priv)
 315 {
 316 }
 317
 318
 319 static void * rate_control_simple_alloc_sta(void *priv, gfp_t gfp)
 320 {
 321         struct sta_rate_control *rctrl;
 322
 323         rctrl = kzalloc(sizeof(*rctrl), gfp);
 324
 325         return rctrl;
 326 }
 327
 328
 329 static void rate_control_simple_free_sta(void *priv, void *priv_sta)
 330 {
 331         struct sta_rate_control *rctrl = priv_sta;
 332         kfree(rctrl);
 333 }
 334
 335 #ifdef CONFIG_MAC80211_DEBUGFS
 336
 337 static int open_file_generic(struct inode *inode, struct file *file)
 338 {
 339         file->private_data = inode->i_private;
 340         return 0;
 341 }
 342
 343 static ssize_t sta_tx_avg_rate_sum_read(struct file *file,
 344                                         char __user *userbuf,
 345                                         size_t count, loff_t *ppos)
 346 {
 347         struct sta_rate_control *srctrl = file->private_data;
 348         char buf[20];
 349
 350         sprintf(buf, "%d\n", srctrl->tx_avg_rate_sum);
 351         return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
 352 }
 353
 354 static const struct file_operations sta_tx_avg_rate_sum_ops = {
 355         .read = sta_tx_avg_rate_sum_read,
 356         .open = open_file_generic,
 357 };
 358
 359 static ssize_t sta_tx_avg_rate_num_read(struct file *file,
 360                                         char __user *userbuf,
 361                                         size_t count, loff_t *ppos)
 362 {
 363         struct sta_rate_control *srctrl = file->private_data;
 364         char buf[20];
 365
 366         sprintf(buf, "%d\n", srctrl->tx_avg_rate_num);
 367         return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
 368 }
 369
 370 static const struct file_operations sta_tx_avg_rate_num_ops = {
 371         .read = sta_tx_avg_rate_num_read,
 372         .open = open_file_generic,
 373 };
 374
 375 static void rate_control_simple_add_sta_debugfs(void *priv, void *priv_sta,
 376                                                 struct dentry *dir)
 377 {
 378         struct sta_rate_control *srctrl = priv_sta;
 379
 380         srctrl->tx_avg_rate_num_dentry =
 381                 debugfs_create_file("rc_simple_sta_tx_avg_rate_num", 0400,
 382                                     dir, srctrl, &sta_tx_avg_rate_num_ops);
 383         srctrl->tx_avg_rate_sum_dentry =
 384                 debugfs_create_file("rc_simple_sta_tx_avg_rate_sum", 0400,
 385                                     dir, srctrl, &sta_tx_avg_rate_sum_ops);
 386 }
 387
 388 static void rate_control_simple_remove_sta_debugfs(void *priv, void *priv_sta)
 389 {
 390         struct sta_rate_control *srctrl = priv_sta;
 391
 392         debugfs_remove(srctrl->tx_avg_rate_sum_dentry);
 393         debugfs_remove(srctrl->tx_avg_rate_num_dentry);
 394 }
 395 #endif
 396
 397 static struct rate_control_ops rate_control_simple = {
 398         .module = THIS_MODULE,
 399         .name = "simple",
 400         .tx_status = rate_control_simple_tx_status,
 401         .get_rate = rate_control_simple_get_rate,
 402         .rate_init = rate_control_simple_rate_init,
 403         .clear = rate_control_simple_clear,
 404         .alloc = rate_control_simple_alloc,
 405         .free = rate_control_simple_free,
 406         .alloc_sta = rate_control_simple_alloc_sta,
 407         .free_sta = rate_control_simple_free_sta,
 408 #ifdef CONFIG_MAC80211_DEBUGFS
 409         .add_sta_debugfs = rate_control_simple_add_sta_debugfs,
 410         .remove_sta_debugfs = rate_control_simple_remove_sta_debugfs,
 411 #endif
 412 };
 413
 414
 415 static int __init rate_control_simple_init(void)
 416 {
 417         return ieee80211_rate_control_register(&rate_control_simple);
 418 }
 419
 420
 421 static void __exit rate_control_simple_exit(void)
 422 {
 423         ieee80211_rate_control_unregister(&rate_control_simple);
 424 }
 425
 426
 427 subsys_initcall(rate_control_simple_init);
 428 module_exit(rate_control_simple_exit);
 429
 430 MODULE_DESCRIPTION("Simple rate control algorithm for ieee80211");
 431 MODULE_LICENSE("GPL");