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/jiffies.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 #include <linux/module.h>
  18
  19 #include <net/mac80211.h>
  20 #include "ieee80211_i.h"
  21 #include "ieee80211_rate.h"
  22 #include "debugfs.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 #define RATE_CONTROL_NUM_DOWN 20
  29 #define RATE_CONTROL_NUM_UP   15
  30
  31 #define RATE_CONTROL_EMERG_DEC 2
  32 #define RATE_CONTROL_INTERVAL (HZ / 20)
  33 #define RATE_CONTROL_MIN_TX 10
  34
  35 static void rate_control_rate_inc(struct ieee80211_local *local,
  36                                   struct sta_info *sta)
  37 {
  38         struct ieee80211_sub_if_data *sdata;
  39         struct ieee80211_supported_band *sband;
  40         int i = sta->txrate_idx;
  41         int maxrate;
  42
  43         sdata = sta->sdata;
  44         if (sdata->bss && sdata->bss->force_unicast_rateidx > -1) {
  45                 /* forced unicast rate - do not change STA rate */
  46                 return;
  47         }
  48
  49         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
  50         maxrate = sdata->bss ? sdata->bss->max_ratectrl_rateidx : -1;
  51
  52         if (i > sband->n_bitrates)
  53                 i = sband->n_bitrates - 2;
  54
  55         while (i + 1 < sband->n_bitrates) {
  56                 i++;
  57                 if (rate_supported(sta, sband->band, i) &&
  58                     (maxrate < 0 || i <= maxrate)) {
  59                         sta->txrate_idx = 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_supported_band *sband;
  71         int i = sta->txrate_idx;
  72
  73         sdata = sta->sdata;
  74         if (sdata->bss && sdata->bss->force_unicast_rateidx > -1) {
  75                 /* forced unicast rate - do not change STA rate */
  76                 return;
  77         }
  78
  79         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
  80         if (i > sband->n_bitrates)
  81                 i = sband->n_bitrates;
  82
  83         while (i > 0) {
  84                 i--;
  85                 if (rate_supported(sta, sband->band, i)) {
  86                         sta->txrate_idx = i;
  87                         break;
  88                 }
  89         }
  90 }
  91
  92 struct global_rate_control {
  93         int dummy;
  94 };
  95
  96 struct sta_rate_control {
  97         unsigned long last_rate_change;
  98         u32 tx_num_failures;
  99         u32 tx_num_xmit;
 100
 101         unsigned long avg_rate_update;
 102         u32 tx_avg_rate_sum;
 103         u32 tx_avg_rate_num;
 104
 105 #ifdef CONFIG_MAC80211_DEBUGFS
 106         struct dentry *tx_avg_rate_sum_dentry;
 107         struct dentry *tx_avg_rate_num_dentry;
 108 #endif
 109 };
 110
 111
 112 static void rate_control_simple_tx_status(void *priv, struct net_device *dev,
 113                                           struct sk_buff *skb,
 114                                           struct ieee80211_tx_status *status)
 115 {
 116         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 117         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 118         struct sta_info *sta;
 119         struct sta_rate_control *srctrl;
 120
 121         rcu_read_lock();
 122
 123         sta = sta_info_get(local, hdr->addr1);
 124
 125         if (!sta)
 126                 goto unlock;
 127
 128         srctrl = sta->rate_ctrl_priv;
 129         srctrl->tx_num_xmit++;
 130         if (status->excessive_retries) {
 131                 srctrl->tx_num_failures++;
 132                 sta->tx_retry_failed++;
 133                 sta->tx_num_consecutive_failures++;
 134                 sta->tx_num_mpdu_fail++;
 135         } else {
 136                 sta->tx_num_consecutive_failures = 0;
 137                 sta->tx_num_mpdu_ok++;
 138         }
 139         sta->tx_retry_count += status->retry_count;
 140         sta->tx_num_mpdu_fail += status->retry_count;
 141
 142         if (time_after(jiffies,
 143                        srctrl->last_rate_change + RATE_CONTROL_INTERVAL) &&
 144                 srctrl->tx_num_xmit > RATE_CONTROL_MIN_TX) {
 145                 u32 per_failed;
 146                 srctrl->last_rate_change = jiffies;
 147
 148                 per_failed = (100 * sta->tx_num_mpdu_fail) /
 149                         (sta->tx_num_mpdu_fail + sta->tx_num_mpdu_ok);
 150                 /* TODO: calculate average per_failed to make adjusting
 151                  * parameters easier */
 152 #if 0
 153                 if (net_ratelimit()) {
 154                         printk(KERN_DEBUG "MPDU fail=%d ok=%d per_failed=%d\n",
 155                                sta->tx_num_mpdu_fail, sta->tx_num_mpdu_ok,
 156                                per_failed);
 157                 }
 158 #endif
 159
 160                 /*
 161                  * XXX: Make these configurable once we have an
 162                  * interface to the rate control algorithms
 163                  */
 164                 if (per_failed > RATE_CONTROL_NUM_DOWN) {
 165                         rate_control_rate_dec(local, sta);
 166                 } else if (per_failed < RATE_CONTROL_NUM_UP) {
 167                         rate_control_rate_inc(local, sta);
 168                 }
 169                 srctrl->tx_avg_rate_sum += status->control.tx_rate->bitrate;
 170                 srctrl->tx_avg_rate_num++;
 171                 srctrl->tx_num_failures = 0;
 172                 srctrl->tx_num_xmit = 0;
 173         } else if (sta->tx_num_consecutive_failures >=
 174                    RATE_CONTROL_EMERG_DEC) {
 175                 rate_control_rate_dec(local, sta);
 176         }
 177
 178         if (time_after(jiffies, srctrl->avg_rate_update + 60 * HZ)) {
 179                 srctrl->avg_rate_update = jiffies;
 180                 if (srctrl->tx_avg_rate_num > 0) {
 181 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 182                         DECLARE_MAC_BUF(mac);
 183                         printk(KERN_DEBUG "%s: STA %s Average rate: "
 184                                "%d (%d/%d)\n",
 185                                dev->name, print_mac(mac, sta->addr),
 186                                srctrl->tx_avg_rate_sum /
 187                                srctrl->tx_avg_rate_num,
 188                                srctrl->tx_avg_rate_sum,
 189                                srctrl->tx_avg_rate_num);
 190 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
 191                         srctrl->tx_avg_rate_sum = 0;
 192                         srctrl->tx_avg_rate_num = 0;
 193                 }
 194         }
 195
 196  unlock:
 197         rcu_read_unlock();
 198 }
 199
 200
 201 static void
 202 rate_control_simple_get_rate(void *priv, struct net_device *dev,
 203                              struct ieee80211_supported_band *sband,
 204                              struct sk_buff *skb,
 205                              struct rate_selection *sel)
 206 {
 207         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 208         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 209         struct ieee80211_sub_if_data *sdata;
 210         struct sta_info *sta;
 211         int rateidx;
 212         u16 fc;
 213
 214         rcu_read_lock();
 215
 216         sta = sta_info_get(local, hdr->addr1);
 217
 218         /* Send management frames and broadcast/multicast data using lowest
 219          * rate. */
 220         fc = le16_to_cpu(hdr->frame_control);
 221         if ((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
 222             is_multicast_ether_addr(hdr->addr1) || !sta) {
 223                 sel->rate = rate_lowest(local, sband, sta);
 224                 rcu_read_unlock();
 225                 return;
 226         }
 227
 228         /* If a forced rate is in effect, select it. */
 229         sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 230         if (sdata->bss && sdata->bss->force_unicast_rateidx > -1)
 231                 sta->txrate_idx = sdata->bss->force_unicast_rateidx;
 232
 233         rateidx = sta->txrate_idx;
 234
 235         if (rateidx >= sband->n_bitrates)
 236                 rateidx = sband->n_bitrates - 1;
 237
 238         sta->last_txrate_idx = rateidx;
 239
 240         rcu_read_unlock();
 241
 242         sel->rate = &sband->bitrates[rateidx];
 243 }
 244
 245
 246 static void rate_control_simple_rate_init(void *priv, void *priv_sta,
 247                                           struct ieee80211_local *local,
 248                                           struct sta_info *sta)
 249 {
 250         struct ieee80211_supported_band *sband;
 251
 252         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 253
 254         /* TODO: This routine should consider using RSSI from previous packets
 255          * as we need to have IEEE 802.1X auth succeed immediately after assoc..
 256          * Until that method is implemented, we will use the lowest supported rate
 257          * as a workaround, */
 258         sta->txrate_idx = rate_lowest_index(local, sband, sta);
 259 }
 260
 261
 262 static void * rate_control_simple_alloc(struct ieee80211_local *local)
 263 {
 264         struct global_rate_control *rctrl;
 265
 266         rctrl = kzalloc(sizeof(*rctrl), GFP_ATOMIC);
 267
 268         return rctrl;
 269 }
 270
 271
 272 static void rate_control_simple_free(void *priv)
 273 {
 274         struct global_rate_control *rctrl = priv;
 275         kfree(rctrl);
 276 }
 277
 278
 279 static void rate_control_simple_clear(void *priv)
 280 {
 281 }
 282
 283
 284 static void * rate_control_simple_alloc_sta(void *priv, gfp_t gfp)
 285 {
 286         struct sta_rate_control *rctrl;
 287
 288         rctrl = kzalloc(sizeof(*rctrl), gfp);
 289
 290         return rctrl;
 291 }
 292
 293
 294 static void rate_control_simple_free_sta(void *priv, void *priv_sta)
 295 {
 296         struct sta_rate_control *rctrl = priv_sta;
 297         kfree(rctrl);
 298 }
 299
 300 #ifdef CONFIG_MAC80211_DEBUGFS
 301
 302 static int open_file_generic(struct inode *inode, struct file *file)
 303 {
 304         file->private_data = inode->i_private;
 305         return 0;
 306 }
 307
 308 static ssize_t sta_tx_avg_rate_sum_read(struct file *file,
 309                                         char __user *userbuf,
 310                                         size_t count, loff_t *ppos)
 311 {
 312         struct sta_rate_control *srctrl = file->private_data;
 313         char buf[20];
 314
 315         sprintf(buf, "%d\n", srctrl->tx_avg_rate_sum);
 316         return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
 317 }
 318
 319 static const struct file_operations sta_tx_avg_rate_sum_ops = {
 320         .read = sta_tx_avg_rate_sum_read,
 321         .open = open_file_generic,
 322 };
 323
 324 static ssize_t sta_tx_avg_rate_num_read(struct file *file,
 325                                         char __user *userbuf,
 326                                         size_t count, loff_t *ppos)
 327 {
 328         struct sta_rate_control *srctrl = file->private_data;
 329         char buf[20];
 330
 331         sprintf(buf, "%d\n", srctrl->tx_avg_rate_num);
 332         return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
 333 }
 334
 335 static const struct file_operations sta_tx_avg_rate_num_ops = {
 336         .read = sta_tx_avg_rate_num_read,
 337         .open = open_file_generic,
 338 };
 339
 340 static void rate_control_simple_add_sta_debugfs(void *priv, void *priv_sta,
 341                                                 struct dentry *dir)
 342 {
 343         struct sta_rate_control *srctrl = priv_sta;
 344
 345         srctrl->tx_avg_rate_num_dentry =
 346                 debugfs_create_file("rc_simple_sta_tx_avg_rate_num", 0400,
 347                                     dir, srctrl, &sta_tx_avg_rate_num_ops);
 348         srctrl->tx_avg_rate_sum_dentry =
 349                 debugfs_create_file("rc_simple_sta_tx_avg_rate_sum", 0400,
 350                                     dir, srctrl, &sta_tx_avg_rate_sum_ops);
 351 }
 352
 353 static void rate_control_simple_remove_sta_debugfs(void *priv, void *priv_sta)
 354 {
 355         struct sta_rate_control *srctrl = priv_sta;
 356
 357         debugfs_remove(srctrl->tx_avg_rate_sum_dentry);
 358         debugfs_remove(srctrl->tx_avg_rate_num_dentry);
 359 }
 360 #endif
 361
 362 static struct rate_control_ops mac80211_rcsimple = {
 363         .name = "simple",
 364         .tx_status = rate_control_simple_tx_status,
 365         .get_rate = rate_control_simple_get_rate,
 366         .rate_init = rate_control_simple_rate_init,
 367         .clear = rate_control_simple_clear,
 368         .alloc = rate_control_simple_alloc,
 369         .free = rate_control_simple_free,
 370         .alloc_sta = rate_control_simple_alloc_sta,
 371         .free_sta = rate_control_simple_free_sta,
 372 #ifdef CONFIG_MAC80211_DEBUGFS
 373         .add_sta_debugfs = rate_control_simple_add_sta_debugfs,
 374         .remove_sta_debugfs = rate_control_simple_remove_sta_debugfs,
 375 #endif
 376 };
 377
 378 MODULE_LICENSE("GPL");
 379 MODULE_DESCRIPTION("Simple rate control algorithm");
 380
 381 int __init rc80211_simple_init(void)
 382 {
 383         return ieee80211_rate_control_register(&mac80211_rcsimple);
 384 }
 385
 386 void rc80211_simple_exit(void)
 387 {
 388         ieee80211_rate_control_unregister(&mac80211_rcsimple);
 389 }
 390
 391 #ifdef CONFIG_MAC80211_RC_SIMPLE_MODULE
 392 module_init(rc80211_simple_init);
 393 module_exit(rc80211_simple_exit);
 394 #endif