net/wireless/core.c

   1 /*
   2  * This is the linux wireless configuration interface.
   3  *
   4  * Copyright 2006, 2007         Johannes Berg <johannes@sipsolutions.net>
   5  */
   6
   7 #include <linux/if.h>
   8 #include <linux/module.h>
   9 #include <linux/err.h>
  10 #include <linux/mutex.h>
  11 #include <linux/list.h>
  12 #include <linux/nl80211.h>
  13 #include <linux/debugfs.h>
  14 #include <linux/notifier.h>
  15 #include <linux/device.h>
  16 #include <net/genetlink.h>
  17 #include <net/cfg80211.h>
  18 #include <net/wireless.h>
  19 #include "core.h"
  20 #include "sysfs.h"
  21
  22 /* name for sysfs, %d is appended */
  23 #define PHY_NAME "phy"
  24
  25 MODULE_AUTHOR("Johannes Berg");
  26 MODULE_LICENSE("GPL");
  27 MODULE_DESCRIPTION("wireless configuration support");
  28
  29 /* RCU might be appropriate here since we usually
  30  * only read the list, and that can happen quite
  31  * often because we need to do it for each command */
  32 LIST_HEAD(cfg80211_drv_list);
  33 DEFINE_MUTEX(cfg80211_drv_mutex);
  34 static int wiphy_counter;
  35
  36 /* for debugfs */
  37 static struct dentry *ieee80211_debugfs_dir;
  38
  39 /* exported functions */
  40
  41 struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
  42 {
  43         struct cfg80211_registered_device *drv;
  44         int alloc_size;
  45
  46         alloc_size = sizeof(*drv) + sizeof_priv;
  47
  48         drv = kzalloc(alloc_size, GFP_KERNEL);
  49         if (!drv)
  50                 return NULL;
  51
  52         drv->ops = ops;
  53
  54         mutex_lock(&cfg80211_drv_mutex);
  55
  56         drv->idx = wiphy_counter;
  57
  58         /* now increase counter for the next device unless
  59          * it has wrapped previously */
  60         if (wiphy_counter >= 0)
  61                 wiphy_counter++;
  62
  63         mutex_unlock(&cfg80211_drv_mutex);
  64
  65         if (unlikely(drv->idx < 0)) {
  66                 /* ugh, wrapped! */
  67                 kfree(drv);
  68                 return NULL;
  69         }
  70
  71         /* give it a proper name */
  72         snprintf(drv->wiphy.dev.bus_id, BUS_ID_SIZE,
  73                  PHY_NAME "%d", drv->idx);
  74
  75         mutex_init(&drv->mtx);
  76         mutex_init(&drv->devlist_mtx);
  77         INIT_LIST_HEAD(&drv->netdev_list);
  78
  79         device_initialize(&drv->wiphy.dev);
  80         drv->wiphy.dev.class = &ieee80211_class;
  81         drv->wiphy.dev.platform_data = drv;
  82
  83         return &drv->wiphy;
  84 }
  85 EXPORT_SYMBOL(wiphy_new);
  86
  87 int wiphy_register(struct wiphy *wiphy)
  88 {
  89         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
  90         int res;
  91
  92         mutex_lock(&cfg80211_drv_mutex);
  93
  94         res = device_add(&drv->wiphy.dev);
  95         if (res)
  96                 goto out_unlock;
  97
  98         list_add(&drv->list, &cfg80211_drv_list);
  99
 100         /* add to debugfs */
 101         drv->wiphy.debugfsdir =
 102                 debugfs_create_dir(wiphy_name(&drv->wiphy),
 103                                    ieee80211_debugfs_dir);
 104
 105         res = 0;
 106 out_unlock:
 107         mutex_unlock(&cfg80211_drv_mutex);
 108         return res;
 109 }
 110 EXPORT_SYMBOL(wiphy_register);
 111
 112 void wiphy_unregister(struct wiphy *wiphy)
 113 {
 114         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 115
 116         /* protect the device list */
 117         mutex_lock(&cfg80211_drv_mutex);
 118
 119         BUG_ON(!list_empty(&drv->netdev_list));
 120
 121         /*
 122          * Try to grab drv->mtx. If a command is still in progress,
 123          * hopefully the driver will refuse it since it's tearing
 124          * down the device already. We wait for this command to complete
 125          * before unlinking the item from the list.
 126          * Note: as codified by the BUG_ON above we cannot get here if
 127          * a virtual interface is still associated. Hence, we can only
 128          * get to lock contention here if userspace issues a command
 129          * that identified the hardware by wiphy index.
 130          */
 131         mutex_lock(&drv->mtx);
 132         /* unlock again before freeing */
 133         mutex_unlock(&drv->mtx);
 134
 135         list_del(&drv->list);
 136         device_del(&drv->wiphy.dev);
 137         debugfs_remove(drv->wiphy.debugfsdir);
 138
 139         mutex_unlock(&cfg80211_drv_mutex);
 140 }
 141 EXPORT_SYMBOL(wiphy_unregister);
 142
 143 void cfg80211_dev_free(struct cfg80211_registered_device *drv)
 144 {
 145         mutex_destroy(&drv->mtx);
 146         mutex_destroy(&drv->devlist_mtx);
 147         kfree(drv);
 148 }
 149
 150 void wiphy_free(struct wiphy *wiphy)
 151 {
 152         put_device(&wiphy->dev);
 153 }
 154 EXPORT_SYMBOL(wiphy_free);
 155
 156 static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
 157                                          unsigned long state,
 158                                          void *ndev)
 159 {
 160         struct net_device *dev = ndev;
 161         struct cfg80211_registered_device *rdev;
 162
 163         if (!dev->ieee80211_ptr)
 164                 return 0;
 165
 166         rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 167
 168         switch (state) {
 169         case NETDEV_REGISTER:
 170                 mutex_lock(&rdev->devlist_mtx);
 171                 list_add(&dev->ieee80211_ptr->list, &rdev->netdev_list);
 172                 if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
 173                                       "phy80211")) {
 174                         printk(KERN_ERR "wireless: failed to add phy80211 "
 175                                 "symlink to netdev!\n");
 176                 }
 177                 dev->ieee80211_ptr->netdev = dev;
 178                 mutex_unlock(&rdev->devlist_mtx);
 179                 break;
 180         case NETDEV_UNREGISTER:
 181                 mutex_lock(&rdev->devlist_mtx);
 182                 if (!list_empty(&dev->ieee80211_ptr->list)) {
 183                         sysfs_remove_link(&dev->dev.kobj, "phy80211");
 184                         list_del_init(&dev->ieee80211_ptr->list);
 185                 }
 186                 mutex_unlock(&rdev->devlist_mtx);
 187                 break;
 188         }
 189
 190         return 0;
 191 }
 192
 193 static struct notifier_block cfg80211_netdev_notifier = {
 194         .notifier_call = cfg80211_netdev_notifier_call,
 195 };
 196
 197 static int cfg80211_init(void)
 198 {
 199         int err = wiphy_sysfs_init();
 200         if (err)
 201                 goto out_fail_sysfs;
 202
 203         err = register_netdevice_notifier(&cfg80211_netdev_notifier);
 204         if (err)
 205                 goto out_fail_notifier;
 206
 207         ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);
 208
 209         return 0;
 210
 211 out_fail_notifier:
 212         wiphy_sysfs_exit();
 213 out_fail_sysfs:
 214         return err;
 215 }
 216 subsys_initcall(cfg80211_init);
 217
 218 static void cfg80211_exit(void)
 219 {
 220         debugfs_remove(ieee80211_debugfs_dir);
 221         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 222         wiphy_sysfs_exit();
 223 }
 224 module_exit(cfg80211_exit);