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/init.h>
  11 #include <linux/netdevice.h>
  12 #include <linux/types.h>
  13 #include <linux/slab.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/compiler.h>
  16 #include <linux/module.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 #define RATE_CONTROL_NUM_DOWN 20
  28 #define RATE_CONTROL_NUM_UP   15
  29
  30 #define RATE_CONTROL_EMERG_DEC 2
  31 #define RATE_CONTROL_INTERVAL (HZ / 20)
  32 #define RATE_CONTROL_MIN_TX 10
  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 struct global_rate_control {
  94         int dummy;
  95 };
  96
  97 struct sta_rate_control {
  98         unsigned long last_rate_change;
  99         u32 tx_num_failures;
 100         u32 tx_num_xmit;
 101
 102         unsigned long avg_rate_update;
 103         u32 tx_avg_rate_sum;
 104         u32 tx_avg_rate_num;
 105
 106 #ifdef CONFIG_MAC80211_DEBUGFS
 107         struct dentry *tx_avg_rate_sum_dentry;
 108         struct dentry *tx_avg_rate_num_dentry;
 109 #endif
 110 };
 111
 112
 113 static void rate_control_simple_tx_status(void *priv, struct net_device *dev,
 114                                           struct sk_buff *skb,
 115                                           struct ieee80211_tx_status *status)
 116 {
 117         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 118         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 119         struct sta_info *sta;
 120         struct sta_rate_control *srctrl;
 121
 122         sta = sta_info_get(local, hdr->addr1);
 123
 124         if (!sta)
 125             return;
 126
 127         srctrl = sta->rate_ctrl_priv;
 128         srctrl->tx_num_xmit++;
 129         if (status->excessive_retries) {
 130                 srctrl->tx_num_failures++;
 131                 sta->tx_retry_failed++;
 132                 sta->tx_num_consecutive_failures++;
 133                 sta->tx_num_mpdu_fail++;
 134         } else {
 135                 sta->last_ack_rssi[0] = sta->last_ack_rssi[1];
 136                 sta->last_ack_rssi[1] = sta->last_ack_rssi[2];
 137                 sta->last_ack_rssi[2] = status->ack_signal;
 138                 sta->tx_num_consecutive_failures = 0;
 139                 sta->tx_num_mpdu_ok++;
 140         }
 141         sta->tx_retry_count += status->retry_count;
 142         sta->tx_num_mpdu_fail += status->retry_count;
 143
 144         if (time_after(jiffies,
 145                        srctrl->last_rate_change + RATE_CONTROL_INTERVAL) &&
 146                 srctrl->tx_num_xmit > RATE_CONTROL_MIN_TX) {
 147                 u32 per_failed;
 148                 srctrl->last_rate_change = jiffies;
 149
 150                 per_failed = (100 * sta->tx_num_mpdu_fail) /
 151                         (sta->tx_num_mpdu_fail + sta->tx_num_mpdu_ok);
 152                 /* TODO: calculate average per_failed to make adjusting
 153                  * parameters easier */
 154 #if 0
 155                 if (net_ratelimit()) {
 156                         printk(KERN_DEBUG "MPDU fail=%d ok=%d per_failed=%d\n",
 157                                sta->tx_num_mpdu_fail, sta->tx_num_mpdu_ok,
 158                                per_failed);
 159                 }
 160 #endif
 161
 162                 /*
 163                  * XXX: Make these configurable once we have an
 164                  * interface to the rate control algorithms
 165                  */
 166                 if (per_failed > RATE_CONTROL_NUM_DOWN) {
 167                         rate_control_rate_dec(local, sta);
 168                 } else if (per_failed < RATE_CONTROL_NUM_UP) {
 169                         rate_control_rate_inc(local, sta);
 170                 }
 171                 srctrl->tx_avg_rate_sum += status->control.rate->rate;
 172                 srctrl->tx_avg_rate_num++;
 173                 srctrl->tx_num_failures = 0;
 174                 srctrl->tx_num_xmit = 0;
 175         } else if (sta->tx_num_consecutive_failures >=
 176                    RATE_CONTROL_EMERG_DEC) {
 177                 rate_control_rate_dec(local, sta);
 178         }
 179
 180         if (srctrl->avg_rate_update + 60 * HZ < jiffies) {
 181                 srctrl->avg_rate_update = jiffies;
 182                 if (srctrl->tx_avg_rate_num > 0) {
 183 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 184                         DECLARE_MAC_BUF(mac);
 185                         printk(KERN_DEBUG "%s: STA %s Average rate: "
 186                                "%d (%d/%d)\n",
 187                                dev->name, print_mac(mac, sta->addr),
 188                                srctrl->tx_avg_rate_sum /
 189                                srctrl->tx_avg_rate_num,
 190                                srctrl->tx_avg_rate_sum,
 191                                srctrl->tx_avg_rate_num);
 192 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
 193                         srctrl->tx_avg_rate_sum = 0;
 194                         srctrl->tx_avg_rate_num = 0;
 195                 }
 196         }
 197
 198         sta_info_put(sta);
 199 }
 200
 201
 202 static void
 203 rate_control_simple_get_rate(void *priv, struct net_device *dev,
 204                              struct ieee80211_hw_mode *mode,
 205                              struct sk_buff *skb,
 206                              struct rate_selection *sel)
 207 {
 208         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 209         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 210         struct ieee80211_sub_if_data *sdata;
 211         struct sta_info *sta;
 212         int rateidx;
 213         u16 fc;
 214
 215         sta = sta_info_get(local, hdr->addr1);
 216
 217         /* Send management frames and broadcast/multicast data using lowest
 218          * rate. */
 219         fc = le16_to_cpu(hdr->frame_control);
 220         if ((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
 221             is_multicast_ether_addr(hdr->addr1) || !sta) {
 222                 sel->rate = rate_lowest(local, mode, sta);
 223                 if (sta)
 224                         sta_info_put(sta);
 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 = sdata->bss->force_unicast_rateidx;
 232
 233         rateidx = sta->txrate;
 234
 235         if (rateidx >= mode->num_rates)
 236                 rateidx = mode->num_rates - 1;
 237
 238         sta->last_txrate = rateidx;
 239
 240         sta_info_put(sta);
 241
 242         sel->rate = &mode->rates[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_hw_mode *mode;
 251         int i;
 252         sta->txrate = 0;
 253         mode = local->oper_hw_mode;
 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         for (i = 0; i < mode->num_rates; i++) {
 259                 if ((sta->supp_rates & BIT(i)) &&
 260                     (mode->rates[i].flags & IEEE80211_RATE_SUPPORTED)) {
 261                         sta->txrate = i;
 262                         break;
 263                 }
 264         }
 265 }
 266
 267
 268 static void * rate_control_simple_alloc(struct ieee80211_local *local)
 269 {
 270         struct global_rate_control *rctrl;
 271
 272         rctrl = kzalloc(sizeof(*rctrl), GFP_ATOMIC);
 273
 274         return rctrl;
 275 }
 276
 277
 278 static void rate_control_simple_free(void *priv)
 279 {
 280         struct global_rate_control *rctrl = priv;
 281         kfree(rctrl);
 282 }
 283
 284
 285 static void rate_control_simple_clear(void *priv)
 286 {
 287 }
 288
 289
 290 static void * rate_control_simple_alloc_sta(void *priv, gfp_t gfp)
 291 {
 292         struct sta_rate_control *rctrl;
 293
 294         rctrl = kzalloc(sizeof(*rctrl), gfp);
 295
 296         return rctrl;
 297 }
 298
 299
 300 static void rate_control_simple_free_sta(void *priv, void *priv_sta)
 301 {
 302         struct sta_rate_control *rctrl = priv_sta;
 303         kfree(rctrl);
 304 }
 305
 306 #ifdef CONFIG_MAC80211_DEBUGFS
 307
 308 static int open_file_generic(struct inode *inode, struct file *file)
 309 {
 310         file->private_data = inode->i_private;
 311         return 0;
 312 }
 313
 314 static ssize_t sta_tx_avg_rate_sum_read(struct file *file,
 315                                         char __user *userbuf,
 316                                         size_t count, loff_t *ppos)
 317 {
 318         struct sta_rate_control *srctrl = file->private_data;
 319         char buf[20];
 320
 321         sprintf(buf, "%d\n", srctrl->tx_avg_rate_sum);
 322         return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
 323 }
 324
 325 static const struct file_operations sta_tx_avg_rate_sum_ops = {
 326         .read = sta_tx_avg_rate_sum_read,
 327         .open = open_file_generic,
 328 };
 329
 330 static ssize_t sta_tx_avg_rate_num_read(struct file *file,
 331                                         char __user *userbuf,
 332                                         size_t count, loff_t *ppos)
 333 {
 334         struct sta_rate_control *srctrl = file->private_data;
 335         char buf[20];
 336
 337         sprintf(buf, "%d\n", srctrl->tx_avg_rate_num);
 338         return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
 339 }
 340
 341 static const struct file_operations sta_tx_avg_rate_num_ops = {
 342         .read = sta_tx_avg_rate_num_read,
 343         .open = open_file_generic,
 344 };
 345
 346 static void rate_control_simple_add_sta_debugfs(void *priv, void *priv_sta,
 347                                                 struct dentry *dir)
 348 {
 349         struct sta_rate_control *srctrl = priv_sta;
 350
 351         srctrl->tx_avg_rate_num_dentry =
 352                 debugfs_create_file("rc_simple_sta_tx_avg_rate_num", 0400,
 353                                     dir, srctrl, &sta_tx_avg_rate_num_ops);
 354         srctrl->tx_avg_rate_sum_dentry =
 355                 debugfs_create_file("rc_simple_sta_tx_avg_rate_sum", 0400,
 356                                     dir, srctrl, &sta_tx_avg_rate_sum_ops);
 357 }
 358
 359 static void rate_control_simple_remove_sta_debugfs(void *priv, void *priv_sta)
 360 {
 361         struct sta_rate_control *srctrl = priv_sta;
 362
 363         debugfs_remove(srctrl->tx_avg_rate_sum_dentry);
 364         debugfs_remove(srctrl->tx_avg_rate_num_dentry);
 365 }
 366 #endif
 367
 368 static struct rate_control_ops mac80211_rcsimple = {
 369         .name = "simple",
 370         .tx_status = rate_control_simple_tx_status,
 371         .get_rate = rate_control_simple_get_rate,
 372         .rate_init = rate_control_simple_rate_init,
 373         .clear = rate_control_simple_clear,
 374         .alloc = rate_control_simple_alloc,
 375         .free = rate_control_simple_free,
 376         .alloc_sta = rate_control_simple_alloc_sta,
 377         .free_sta = rate_control_simple_free_sta,
 378 #ifdef CONFIG_MAC80211_DEBUGFS
 379         .add_sta_debugfs = rate_control_simple_add_sta_debugfs,
 380         .remove_sta_debugfs = rate_control_simple_remove_sta_debugfs,
 381 #endif
 382 };
 383
 384 MODULE_LICENSE("GPL");
 385 MODULE_DESCRIPTION("Simple rate control algorithm");
 386
 387 int __init rc80211_simple_init(void)
 388 {
 389         return ieee80211_rate_control_register(&mac80211_rcsimple);
 390 }
 391
 392 void __exit rc80211_simple_exit(void)
 393 {
 394         ieee80211_rate_control_unregister(&mac80211_rcsimple);
 395 }
 396
 397 #ifdef CONFIG_MAC80211_RC_SIMPLE_MODULE
 398 module_init(rc80211_simple_init);
 399 module_exit(rc80211_simple_exit);
 400 #endif