net/mac80211/ieee80211_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 "ieee80211_rate.h"
  14 #include "ieee80211_i.h"
  15
  16 struct rate_control_alg {
  17         struct list_head list;
  18         struct rate_control_ops *ops;
  19 };
  20
  21 static LIST_HEAD(rate_ctrl_algs);
  22 static DEFINE_MUTEX(rate_ctrl_mutex);
  23
  24 static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
  25 module_param(ieee80211_default_rc_algo, charp, 0644);
  26 MODULE_PARM_DESC(ieee80211_default_rc_algo,
  27                  "Default rate control algorithm for mac80211 to use");
  28
  29 int ieee80211_rate_control_register(struct rate_control_ops *ops)
  30 {
  31         struct rate_control_alg *alg;
  32
  33         if (!ops->name)
  34                 return -EINVAL;
  35
  36         mutex_lock(&rate_ctrl_mutex);
  37         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  38                 if (!strcmp(alg->ops->name, ops->name)) {
  39                         /* don't register an algorithm twice */
  40                         WARN_ON(1);
  41                         mutex_unlock(&rate_ctrl_mutex);
  42                         return -EALREADY;
  43                 }
  44         }
  45
  46         alg = kzalloc(sizeof(*alg), GFP_KERNEL);
  47         if (alg == NULL) {
  48                 mutex_unlock(&rate_ctrl_mutex);
  49                 return -ENOMEM;
  50         }
  51         alg->ops = ops;
  52
  53         list_add_tail(&alg->list, &rate_ctrl_algs);
  54         mutex_unlock(&rate_ctrl_mutex);
  55
  56         return 0;
  57 }
  58 EXPORT_SYMBOL(ieee80211_rate_control_register);
  59
  60 void ieee80211_rate_control_unregister(struct rate_control_ops *ops)
  61 {
  62         struct rate_control_alg *alg;
  63
  64         mutex_lock(&rate_ctrl_mutex);
  65         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  66                 if (alg->ops == ops) {
  67                         list_del(&alg->list);
  68                         kfree(alg);
  69                         break;
  70                 }
  71         }
  72         mutex_unlock(&rate_ctrl_mutex);
  73 }
  74 EXPORT_SYMBOL(ieee80211_rate_control_unregister);
  75
  76 static struct rate_control_ops *
  77 ieee80211_try_rate_control_ops_get(const char *name)
  78 {
  79         struct rate_control_alg *alg;
  80         struct rate_control_ops *ops = NULL;
  81
  82         if (!name)
  83                 return NULL;
  84
  85         mutex_lock(&rate_ctrl_mutex);
  86         list_for_each_entry(alg, &rate_ctrl_algs, list) {
  87                 if (!strcmp(alg->ops->name, name))
  88                         if (try_module_get(alg->ops->module)) {
  89                                 ops = alg->ops;
  90                                 break;
  91                         }
  92         }
  93         mutex_unlock(&rate_ctrl_mutex);
  94         return ops;
  95 }
  96
  97 /* Get the rate control algorithm. */
  98 static struct rate_control_ops *
  99 ieee80211_rate_control_ops_get(const char *name)
 100 {
 101         struct rate_control_ops *ops;
 102         const char *alg_name;
 103
 104         if (!name)
 105                 alg_name = ieee80211_default_rc_algo;
 106         else
 107                 alg_name = name;
 108
 109         ops = ieee80211_try_rate_control_ops_get(alg_name);
 110         if (!ops) {
 111                 request_module("rc80211_%s", alg_name);
 112                 ops = ieee80211_try_rate_control_ops_get(alg_name);
 113         }
 114         if (!ops && name)
 115                 /* try default if specific alg requested but not found */
 116                 ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
 117
 118         return ops;
 119 }
 120
 121 static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
 122 {
 123         module_put(ops->module);
 124 }
 125
 126 struct rate_control_ref *rate_control_alloc(const char *name,
 127                                             struct ieee80211_local *local)
 128 {
 129         struct rate_control_ref *ref;
 130
 131         ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
 132         if (!ref)
 133                 goto fail_ref;
 134         kref_init(&ref->kref);
 135         ref->ops = ieee80211_rate_control_ops_get(name);
 136         if (!ref->ops)
 137                 goto fail_ops;
 138         ref->priv = ref->ops->alloc(local);
 139         if (!ref->priv)
 140                 goto fail_priv;
 141         return ref;
 142
 143 fail_priv:
 144         ieee80211_rate_control_ops_put(ref->ops);
 145 fail_ops:
 146         kfree(ref);
 147 fail_ref:
 148         return NULL;
 149 }
 150
 151 static void rate_control_release(struct kref *kref)
 152 {
 153         struct rate_control_ref *ctrl_ref;
 154
 155         ctrl_ref = container_of(kref, struct rate_control_ref, kref);
 156         ctrl_ref->ops->free(ctrl_ref->priv);
 157         ieee80211_rate_control_ops_put(ctrl_ref->ops);
 158         kfree(ctrl_ref);
 159 }
 160
 161 void rate_control_get_rate(struct net_device *dev,
 162                            struct ieee80211_hw_mode *mode, struct sk_buff *skb,
 163                            struct rate_selection *sel)
 164 {
 165         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 166         struct rate_control_ref *ref = local->rate_ctrl;
 167         struct ieee80211_sub_if_data *sdata;
 168         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 169         struct sta_info *sta = sta_info_get(local, hdr->addr1);
 170         int i;
 171         u16 fc;
 172
 173         memset(sel, 0, sizeof(struct rate_selection));
 174
 175         /* Send management frames and broadcast/multicast data using lowest
 176          * rate. */
 177         fc = le16_to_cpu(hdr->frame_control);
 178         if ((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
 179             is_multicast_ether_addr(hdr->addr1))
 180                 sel->rate = rate_lowest(local, mode, sta);
 181
 182         /* If a forced rate is in effect, select it. */
 183         sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 184         if (sdata->bss && sdata->bss->force_unicast_rateidx > -1)
 185                 sel->rate = &mode->rates[sdata->bss->force_unicast_rateidx];
 186
 187         /* If we haven't found the rate yet, ask the rate control algo. */
 188         if (!sel->rate)
 189                 ref->ops->get_rate(ref->priv, dev, mode, skb, sel);
 190
 191         /* Select a non-ERP backup rate. */
 192         if (!sel->nonerp) {
 193                 for (i = 0; i < mode->num_rates - 1; i++) {
 194                         struct ieee80211_rate *rate = &mode->rates[i];
 195                         if (sel->rate->rate < rate->rate)
 196                                 break;
 197
 198                         if (rate_supported(sta, mode, i) &&
 199                             !(rate->flags & IEEE80211_RATE_ERP))
 200                                 sel->nonerp = rate;
 201                 }
 202         }
 203
 204         if (sta)
 205                 sta_info_put(sta);
 206 }
 207
 208 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)
 209 {
 210         kref_get(&ref->kref);
 211         return ref;
 212 }
 213
 214 void rate_control_put(struct rate_control_ref *ref)
 215 {
 216         kref_put(&ref->kref, rate_control_release);
 217 }
 218
 219 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
 220                                  const char *name)
 221 {
 222         struct rate_control_ref *ref, *old;
 223
 224         ASSERT_RTNL();
 225         if (local->open_count || netif_running(local->mdev))
 226                 return -EBUSY;
 227
 228         ref = rate_control_alloc(name, local);
 229         if (!ref) {
 230                 printk(KERN_WARNING "%s: Failed to select rate control "
 231                        "algorithm\n", wiphy_name(local->hw.wiphy));
 232                 return -ENOENT;
 233         }
 234
 235         old = local->rate_ctrl;
 236         local->rate_ctrl = ref;
 237         if (old) {
 238                 rate_control_put(old);
 239                 sta_info_flush(local, NULL);
 240         }
 241
 242         printk(KERN_DEBUG "%s: Selected rate control "
 243                "algorithm '%s'\n", wiphy_name(local->hw.wiphy),
 244                ref->ops->name);
 245
 246
 247         return 0;
 248 }
 249
 250 void rate_control_deinitialize(struct ieee80211_local *local)
 251 {
 252         struct rate_control_ref *ref;
 253
 254         ref = local->rate_ctrl;
 255         local->rate_ctrl = NULL;
 256         rate_control_put(ref);
 257 }
 258