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