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 "nl80211.h"
  20 #include "core.h"
  21 #include "sysfs.h"
  22
  23 /* name for sysfs, %d is appended */
  24 #define PHY_NAME "phy"
  25
  26 MODULE_AUTHOR("Johannes Berg");
  27 MODULE_LICENSE("GPL");
  28 MODULE_DESCRIPTION("wireless configuration support");
  29
  30 /* RCU might be appropriate here since we usually
  31  * only read the list, and that can happen quite
  32  * often because we need to do it for each command */
  33 LIST_HEAD(cfg80211_drv_list);
  34 DEFINE_MUTEX(cfg80211_drv_mutex);
  35 static int wiphy_counter;
  36
  37 /* for debugfs */
  38 static struct dentry *ieee80211_debugfs_dir;
  39
  40 /* requires cfg80211_drv_mutex to be held! */
  41 static struct cfg80211_registered_device *cfg80211_drv_by_wiphy(int wiphy)
  42 {
  43         struct cfg80211_registered_device *result = NULL, *drv;
  44
  45         list_for_each_entry(drv, &cfg80211_drv_list, list) {
  46                 if (drv->idx == wiphy) {
  47                         result = drv;
  48                         break;
  49                 }
  50         }
  51
  52         return result;
  53 }
  54
  55 /* requires cfg80211_drv_mutex to be held! */
  56 static struct cfg80211_registered_device *
  57 __cfg80211_drv_from_info(struct genl_info *info)
  58 {
  59         int ifindex;
  60         struct cfg80211_registered_device *bywiphy = NULL, *byifidx = NULL;
  61         struct net_device *dev;
  62         int err = -EINVAL;
  63
  64         if (info->attrs[NL80211_ATTR_WIPHY]) {
  65                 bywiphy = cfg80211_drv_by_wiphy(
  66                                 nla_get_u32(info->attrs[NL80211_ATTR_WIPHY]));
  67                 err = -ENODEV;
  68         }
  69
  70         if (info->attrs[NL80211_ATTR_IFINDEX]) {
  71                 ifindex = nla_get_u32(info->attrs[NL80211_ATTR_IFINDEX]);
  72                 dev = dev_get_by_index(&init_net, ifindex);
  73                 if (dev) {
  74                         if (dev->ieee80211_ptr)
  75                                 byifidx =
  76                                         wiphy_to_dev(dev->ieee80211_ptr->wiphy);
  77                         dev_put(dev);
  78                 }
  79                 err = -ENODEV;
  80         }
  81
  82         if (bywiphy && byifidx) {
  83                 if (bywiphy != byifidx)
  84                         return ERR_PTR(-EINVAL);
  85                 else
  86                         return bywiphy; /* == byifidx */
  87         }
  88         if (bywiphy)
  89                 return bywiphy;
  90
  91         if (byifidx)
  92                 return byifidx;
  93
  94         return ERR_PTR(err);
  95 }
  96
  97 struct cfg80211_registered_device *
  98 cfg80211_get_dev_from_info(struct genl_info *info)
  99 {
 100         struct cfg80211_registered_device *drv;
 101
 102         mutex_lock(&cfg80211_drv_mutex);
 103         drv = __cfg80211_drv_from_info(info);
 104
 105         /* if it is not an error we grab the lock on
 106          * it to assure it won't be going away while
 107          * we operate on it */
 108         if (!IS_ERR(drv))
 109                 mutex_lock(&drv->mtx);
 110
 111         mutex_unlock(&cfg80211_drv_mutex);
 112
 113         return drv;
 114 }
 115
 116 struct cfg80211_registered_device *
 117 cfg80211_get_dev_from_ifindex(int ifindex)
 118 {
 119         struct cfg80211_registered_device *drv = ERR_PTR(-ENODEV);
 120         struct net_device *dev;
 121
 122         mutex_lock(&cfg80211_drv_mutex);
 123         dev = dev_get_by_index(&init_net, ifindex);
 124         if (!dev)
 125                 goto out;
 126         if (dev->ieee80211_ptr) {
 127                 drv = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 128                 mutex_lock(&drv->mtx);
 129         } else
 130                 drv = ERR_PTR(-ENODEV);
 131         dev_put(dev);
 132  out:
 133         mutex_unlock(&cfg80211_drv_mutex);
 134         return drv;
 135 }
 136
 137 void cfg80211_put_dev(struct cfg80211_registered_device *drv)
 138 {
 139         BUG_ON(IS_ERR(drv));
 140         mutex_unlock(&drv->mtx);
 141 }
 142
 143 int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
 144                         char *newname)
 145 {
 146         int idx, taken = -1, result, digits;
 147
 148         /* prohibit calling the thing phy%d when %d is not its number */
 149         sscanf(newname, PHY_NAME "%d%n", &idx, &taken);
 150         if (taken == strlen(newname) && idx != rdev->idx) {
 151                 /* count number of places needed to print idx */
 152                 digits = 1;
 153                 while (idx /= 10)
 154                         digits++;
 155                 /*
 156                  * deny the name if it is phy<idx> where <idx> is printed
 157                  * without leading zeroes. taken == strlen(newname) here
 158                  */
 159                 if (taken == strlen(PHY_NAME) + digits)
 160                         return -EINVAL;
 161         }
 162
 163         /* this will check for collisions */
 164         result = device_rename(&rdev->wiphy.dev, newname);
 165         if (result)
 166                 return result;
 167
 168         if (!debugfs_rename(rdev->wiphy.debugfsdir->d_parent,
 169                             rdev->wiphy.debugfsdir,
 170                             rdev->wiphy.debugfsdir->d_parent,
 171                             newname))
 172                 printk(KERN_ERR "cfg80211: failed to rename debugfs dir to %s!\n",
 173                        newname);
 174
 175         nl80211_notify_dev_rename(rdev);
 176
 177         return 0;
 178 }
 179
 180 /* exported functions */
 181
 182 struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
 183 {
 184         struct cfg80211_registered_device *drv;
 185         int alloc_size;
 186
 187         alloc_size = sizeof(*drv) + sizeof_priv;
 188
 189         drv = kzalloc(alloc_size, GFP_KERNEL);
 190         if (!drv)
 191                 return NULL;
 192
 193         drv->ops = ops;
 194
 195         mutex_lock(&cfg80211_drv_mutex);
 196
 197         drv->idx = wiphy_counter;
 198
 199         /* now increase counter for the next device unless
 200          * it has wrapped previously */
 201         if (wiphy_counter >= 0)
 202                 wiphy_counter++;
 203
 204         mutex_unlock(&cfg80211_drv_mutex);
 205
 206         if (unlikely(drv->idx < 0)) {
 207                 /* ugh, wrapped! */
 208                 kfree(drv);
 209                 return NULL;
 210         }
 211
 212         /* give it a proper name */
 213         snprintf(drv->wiphy.dev.bus_id, BUS_ID_SIZE,
 214                  PHY_NAME "%d", drv->idx);
 215
 216         mutex_init(&drv->mtx);
 217         mutex_init(&drv->devlist_mtx);
 218         INIT_LIST_HEAD(&drv->netdev_list);
 219
 220         device_initialize(&drv->wiphy.dev);
 221         drv->wiphy.dev.class = &ieee80211_class;
 222         drv->wiphy.dev.platform_data = drv;
 223
 224         return &drv->wiphy;
 225 }
 226 EXPORT_SYMBOL(wiphy_new);
 227
 228 int wiphy_register(struct wiphy *wiphy)
 229 {
 230         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 231         int res;
 232
 233         mutex_lock(&cfg80211_drv_mutex);
 234
 235         res = device_add(&drv->wiphy.dev);
 236         if (res)
 237                 goto out_unlock;
 238
 239         list_add(&drv->list, &cfg80211_drv_list);
 240
 241         /* add to debugfs */
 242         drv->wiphy.debugfsdir =
 243                 debugfs_create_dir(wiphy_name(&drv->wiphy),
 244                                    ieee80211_debugfs_dir);
 245
 246         res = 0;
 247 out_unlock:
 248         mutex_unlock(&cfg80211_drv_mutex);
 249         return res;
 250 }
 251 EXPORT_SYMBOL(wiphy_register);
 252
 253 void wiphy_unregister(struct wiphy *wiphy)
 254 {
 255         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 256
 257         /* protect the device list */
 258         mutex_lock(&cfg80211_drv_mutex);
 259
 260         BUG_ON(!list_empty(&drv->netdev_list));
 261
 262         /*
 263          * Try to grab drv->mtx. If a command is still in progress,
 264          * hopefully the driver will refuse it since it's tearing
 265          * down the device already. We wait for this command to complete
 266          * before unlinking the item from the list.
 267          * Note: as codified by the BUG_ON above we cannot get here if
 268          * a virtual interface is still associated. Hence, we can only
 269          * get to lock contention here if userspace issues a command
 270          * that identified the hardware by wiphy index.
 271          */
 272         mutex_lock(&drv->mtx);
 273         /* unlock again before freeing */
 274         mutex_unlock(&drv->mtx);
 275
 276         list_del(&drv->list);
 277         device_del(&drv->wiphy.dev);
 278         debugfs_remove(drv->wiphy.debugfsdir);
 279
 280         mutex_unlock(&cfg80211_drv_mutex);
 281 }
 282 EXPORT_SYMBOL(wiphy_unregister);
 283
 284 void cfg80211_dev_free(struct cfg80211_registered_device *drv)
 285 {
 286         mutex_destroy(&drv->mtx);
 287         mutex_destroy(&drv->devlist_mtx);
 288         kfree(drv);
 289 }
 290
 291 void wiphy_free(struct wiphy *wiphy)
 292 {
 293         put_device(&wiphy->dev);
 294 }
 295 EXPORT_SYMBOL(wiphy_free);
 296
 297 static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
 298                                          unsigned long state,
 299                                          void *ndev)
 300 {
 301         struct net_device *dev = ndev;
 302         struct cfg80211_registered_device *rdev;
 303
 304         if (!dev->ieee80211_ptr)
 305                 return 0;
 306
 307         rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 308
 309         switch (state) {
 310         case NETDEV_REGISTER:
 311                 mutex_lock(&rdev->devlist_mtx);
 312                 list_add(&dev->ieee80211_ptr->list, &rdev->netdev_list);
 313                 if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
 314                                       "phy80211")) {
 315                         printk(KERN_ERR "wireless: failed to add phy80211 "
 316                                 "symlink to netdev!\n");
 317                 }
 318                 dev->ieee80211_ptr->netdev = dev;
 319                 mutex_unlock(&rdev->devlist_mtx);
 320                 break;
 321         case NETDEV_UNREGISTER:
 322                 mutex_lock(&rdev->devlist_mtx);
 323                 if (!list_empty(&dev->ieee80211_ptr->list)) {
 324                         sysfs_remove_link(&dev->dev.kobj, "phy80211");
 325                         list_del_init(&dev->ieee80211_ptr->list);
 326                 }
 327                 mutex_unlock(&rdev->devlist_mtx);
 328                 break;
 329         }
 330
 331         return 0;
 332 }
 333
 334 static struct notifier_block cfg80211_netdev_notifier = {
 335         .notifier_call = cfg80211_netdev_notifier_call,
 336 };
 337
 338 static int cfg80211_init(void)
 339 {
 340         int err = wiphy_sysfs_init();
 341         if (err)
 342                 goto out_fail_sysfs;
 343
 344         err = register_netdevice_notifier(&cfg80211_netdev_notifier);
 345         if (err)
 346                 goto out_fail_notifier;
 347
 348         err = nl80211_init();
 349         if (err)
 350                 goto out_fail_nl80211;
 351
 352         ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);
 353
 354         return 0;
 355
 356 out_fail_nl80211:
 357         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 358 out_fail_notifier:
 359         wiphy_sysfs_exit();
 360 out_fail_sysfs:
 361         return err;
 362 }
 363 subsys_initcall(cfg80211_init);
 364
 365 static void cfg80211_exit(void)
 366 {
 367         debugfs_remove(ieee80211_debugfs_dir);
 368         nl80211_exit();
 369         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 370         wiphy_sysfs_exit();
 371 }
 372 module_exit(cfg80211_exit);