net/mac80211/rate.c

   1 /*
   2  * Copyright 2002-2005, Instant802 Networks, Inc.
   3  * Copyright 2005-2006, Devicescape Software, Inc.
   4  * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/rtnetlink.h>
  13 #include "rate.h"
  14 #include "ieee80211_i.h"
  15 #include "debugfs.h"
  16
  17 struct rate_control_alg {
  18         struct list_head list;
  19         struct rate_control_ops *ops;
  20 };
  21
  22 static LIST_HEAD(rate_ctrl_algs);
  23 static DEFINE_MUTEX(rate_ctrl_mutex);
  24
  25 static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
  26 module_param(ieee80211_default_rc_algo, charp, 0644);
  27 MODULE_PARM_DESC(ieee80211_default_rc_algo,
  28                  "Default rate control algorithm for mac80211 to use");
  29
  30 int ieee80211_rate_control_register(struct rate_control_ops *ops)
  31 {
  32         struct rate_control_alg *alg;
  33
  34         if (!ops->name)
  35                 return -EINVAL;
  36
  37         mutex_lock(&rate_ctrl_mutex);
  38         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  39                 if (!strcmp(alg->ops->name, ops->name)) {
  40                         /* don't register an algorithm twice */
  41                         WARN_ON(1);
  42                         mutex_unlock(&rate_ctrl_mutex);
  43                         return -EALREADY;
  44                 }
  45         }
  46
  47         alg = kzalloc(sizeof(*alg), GFP_KERNEL);
  48         if (alg == NULL) {
  49                 mutex_unlock(&rate_ctrl_mutex);
  50                 return -ENOMEM;
  51         }
  52         alg->ops = ops;
  53
  54         list_add_tail(&alg->list, &rate_ctrl_algs);
  55         mutex_unlock(&rate_ctrl_mutex);
  56
  57         return 0;
  58 }
  59 EXPORT_SYMBOL(ieee80211_rate_control_register);
  60
  61 void ieee80211_rate_control_unregister(struct rate_control_ops *ops)
  62 {
  63         struct rate_control_alg *alg;
  64
  65         mutex_lock(&rate_ctrl_mutex);
  66         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  67                 if (alg->ops == ops) {
  68                         list_del(&alg->list);
  69                         kfree(alg);
  70                         break;
  71                 }
  72         }
  73         mutex_unlock(&rate_ctrl_mutex);
  74 }
  75 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
  76
  77 static struct rate_control_ops *
  78 ieee80211_try_rate_control_ops_get(const char *name)
  79 {
  80         struct rate_control_alg *alg;
  81         struct rate_control_ops *ops = NULL;
  82
  83         if (!name)
  84                 return NULL;
  85
  86         mutex_lock(&rate_ctrl_mutex);
  87         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  88                 if (!strcmp(alg->ops->name, name))
  89                         if (try_module_get(alg->ops->module)) {
  90                                 ops = alg->ops;
  91                                 break;
  92                         }
  93         }
  94         mutex_unlock(&rate_ctrl_mutex);
  95         return ops;
  96 }
  97
  98 /* Get the rate control algorithm. */
  99 static struct rate_control_ops *
 100 ieee80211_rate_control_ops_get(const char *name)
 101 {
 102         struct rate_control_ops *ops;
 103         const char *alg_name;
 104
 105         if (!name)
 106                 alg_name = ieee80211_default_rc_algo;
 107         else
 108                 alg_name = name;
 109
 110         ops = ieee80211_try_rate_control_ops_get(alg_name);
 111         if (!ops) {
 112                 request_module("rc80211_%s", alg_name);
 113                 ops = ieee80211_try_rate_control_ops_get(alg_name);
 114         }
 115         if (!ops && name)
 116                 /* try default if specific alg requested but not found */
 117                 ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
 118
 119         /* try built-in one if specific alg requested but not found */
 120         if (!ops && strlen(CONFIG_MAC80211_RC_DEFAULT))
 121                 ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
 122
 123         return ops;
 124 }
 125
 126 static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
 127 {
 128         module_put(ops->module);
 129 }
 130
 131 #ifdef CONFIG_MAC80211_DEBUGFS
 132 static ssize_t rcname_read(struct file *file, char __user *userbuf,
 133                            size_t count, loff_t *ppos)
 134 {
 135         struct rate_control_ref *ref = file->private_data;
 136         int len = strlen(ref->ops->name);
 137
 138         return simple_read_from_buffer(userbuf, count, ppos,
 139                                        ref->ops->name, len);
 140 }
 141
 142 static const struct file_operations rcname_ops = {
 143         .read = rcname_read,
 144         .open = mac80211_open_file_generic,
 145 };
 146 #endif
 147
 148 struct rate_control_ref *rate_control_alloc(const char *name,
 149                                             struct ieee80211_local *local)
 150 {
 151         struct dentry *debugfsdir = NULL;
 152         struct rate_control_ref *ref;
 153
 154         ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
 155         if (!ref)
 156                 goto fail_ref;
 157         kref_init(&ref->kref);
 158         ref->local = local;
 159         ref->ops = ieee80211_rate_control_ops_get(name);
 160         if (!ref->ops)
 161                 goto fail_ops;
 162
 163 #ifdef CONFIG_MAC80211_DEBUGFS
 164         debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
 165         local->debugfs.rcdir = debugfsdir;
 166         local->debugfs.rcname = debugfs_create_file("name", 0400, debugfsdir,
 167                                                     ref, &rcname_ops);
 168 #endif
 169
 170         ref->priv = ref->ops->alloc(&local->hw, debugfsdir);
 171         if (!ref->priv)
 172                 goto fail_priv;
 173         return ref;
 174
 175 fail_priv:
 176         ieee80211_rate_control_ops_put(ref->ops);
 177 fail_ops:
 178         kfree(ref);
 179 fail_ref:
 180         return NULL;
 181 }
 182
 183 static void rate_control_release(struct kref *kref)
 184 {
 185         struct rate_control_ref *ctrl_ref;
 186
 187         ctrl_ref = container_of(kref, struct rate_control_ref, kref);
 188         ctrl_ref->ops->free(ctrl_ref->priv);
 189
 190 #ifdef CONFIG_MAC80211_DEBUGFS
 191         debugfs_remove(ctrl_ref->local->debugfs.rcname);
 192         ctrl_ref->local->debugfs.rcname = NULL;
 193         debugfs_remove(ctrl_ref->local->debugfs.rcdir);
 194         ctrl_ref->local->debugfs.rcdir = NULL;
 195 #endif
 196
 197         ieee80211_rate_control_ops_put(ctrl_ref->ops);
 198         kfree(ctrl_ref);
 199 }
 200
 201 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
 202                            struct ieee80211_supported_band *sband,
 203                            struct sta_info *sta, struct sk_buff *skb,
 204                            struct rate_selection *sel)
 205 {
 206         struct rate_control_ref *ref = sdata->local->rate_ctrl;
 207         void *priv_sta = NULL;
 208         struct ieee80211_sta *ista = NULL;
 209         int i;
 210
 211         sel->rate_idx = -1;
 212         sel->nonerp_idx = -1;
 213         sel->probe_idx = -1;
 214         sel->max_rate_idx = sdata->max_ratectrl_rateidx;
 215
 216         if (sta) {
 217                 ista = &sta->sta;
 218                 priv_sta = sta->rate_ctrl_priv;
 219         }
 220
 221         if (sta && sdata->force_unicast_rateidx > -1)
 222                 sel->rate_idx = sdata->force_unicast_rateidx;
 223         else
 224                 ref->ops->get_rate(ref->priv, sband, ista, priv_sta, skb, sel);
 225
 226         if (sdata->max_ratectrl_rateidx > -1 &&
 227             sel->rate_idx > sdata->max_ratectrl_rateidx)
 228                 sel->rate_idx = sdata->max_ratectrl_rateidx;
 229
 230         BUG_ON(sel->rate_idx < 0);
 231
 232         /* Select a non-ERP backup rate. */
 233         if (sel->nonerp_idx < 0) {
 234                 for (i = 0; i < sband->n_bitrates; i++) {
 235                         struct ieee80211_rate *rate = &sband->bitrates[i];
 236                         if (sband->bitrates[sel->rate_idx].bitrate < rate->bitrate)
 237                                 break;
 238
 239                         if (rate_supported(ista, sband->band, i) &&
 240                             !(rate->flags & IEEE80211_RATE_ERP_G))
 241                                 sel->nonerp_idx = i;
 242                 }
 243         }
 244 }
 245
 246 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)
 247 {
 248         kref_get(&ref->kref);
 249         return ref;
 250 }
 251
 252 void rate_control_put(struct rate_control_ref *ref)
 253 {
 254         kref_put(&ref->kref, rate_control_release);
 255 }
 256
 257 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
 258                                  const char *name)
 259 {
 260         struct rate_control_ref *ref, *old;
 261
 262         ASSERT_RTNL();
 263         if (local->open_count || netif_running(local->mdev))
 264                 return -EBUSY;
 265
 266         ref = rate_control_alloc(name, local);
 267         if (!ref) {
 268                 printk(KERN_WARNING "%s: Failed to select rate control "
 269                        "algorithm\n", wiphy_name(local->hw.wiphy));
 270                 return -ENOENT;
 271         }
 272
 273         old = local->rate_ctrl;
 274         local->rate_ctrl = ref;
 275         if (old) {
 276                 rate_control_put(old);
 277                 sta_info_flush(local, NULL);
 278         }
 279
 280         printk(KERN_DEBUG "%s: Selected rate control "
 281                "algorithm '%s'\n", wiphy_name(local->hw.wiphy),
 282                ref->ops->name);
 283
 284
 285         return 0;
 286 }
 287
 288 void rate_control_deinitialize(struct ieee80211_local *local)
 289 {
 290         struct rate_control_ref *ref;
 291
 292         ref = local->rate_ctrl;
 293         local->rate_ctrl = NULL;
 294         rate_control_put(ref);
 295 }
 296