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         struct cfg80211_registered_device *drv;
 147         int idx, taken = -1, result, digits;
 148
 149         mutex_lock(&cfg80211_drv_mutex);
 150
 151         /* prohibit calling the thing phy%d when %d is not its number */
 152         sscanf(newname, PHY_NAME "%d%n", &idx, &taken);
 153         if (taken == strlen(newname) && idx != rdev->idx) {
 154                 /* count number of places needed to print idx */
 155                 digits = 1;
 156                 while (idx /= 10)
 157                         digits++;
 158                 /*
 159                  * deny the name if it is phy<idx> where <idx> is printed
 160                  * without leading zeroes. taken == strlen(newname) here
 161                  */
 162                 result = -EINVAL;
 163                 if (taken == strlen(PHY_NAME) + digits)
 164                         goto out_unlock;
 165         }
 166
 167
 168         /* Ignore nop renames */
 169         result = 0;
 170         if (strcmp(newname, dev_name(&rdev->wiphy.dev)) == 0)
 171                 goto out_unlock;
 172
 173         /* Ensure another device does not already have this name. */
 174         list_for_each_entry(drv, &cfg80211_drv_list, list) {
 175                 result = -EINVAL;
 176                 if (strcmp(newname, dev_name(&drv->wiphy.dev)) == 0)
 177                         goto out_unlock;
 178         }
 179
 180         /* this will only check for collisions in sysfs
 181          * which is not even always compiled in.
 182          */
 183         result = device_rename(&rdev->wiphy.dev, newname);
 184         if (result)
 185                 goto out_unlock;
 186
 187         if (!debugfs_rename(rdev->wiphy.debugfsdir->d_parent,
 188                             rdev->wiphy.debugfsdir,
 189                             rdev->wiphy.debugfsdir->d_parent,
 190                             newname))
 191                 printk(KERN_ERR "cfg80211: failed to rename debugfs dir to %s!\n",
 192                        newname);
 193
 194         result = 0;
 195 out_unlock:
 196         mutex_unlock(&cfg80211_drv_mutex);
 197         if (result == 0)
 198                 nl80211_notify_dev_rename(rdev);
 199
 200         return result;
 201 }
 202
 203 /* exported functions */
 204
 205 struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
 206 {
 207         struct cfg80211_registered_device *drv;
 208         int alloc_size;
 209
 210         WARN_ON(!ops->add_key && ops->del_key);
 211         WARN_ON(ops->add_key && !ops->del_key);
 212
 213         alloc_size = sizeof(*drv) + sizeof_priv;
 214
 215         drv = kzalloc(alloc_size, GFP_KERNEL);
 216         if (!drv)
 217                 return NULL;
 218
 219         drv->ops = ops;
 220
 221         mutex_lock(&cfg80211_drv_mutex);
 222
 223         drv->idx = wiphy_counter;
 224
 225         /* now increase counter for the next device unless
 226          * it has wrapped previously */
 227         if (wiphy_counter >= 0)
 228                 wiphy_counter++;
 229
 230         mutex_unlock(&cfg80211_drv_mutex);
 231
 232         if (unlikely(drv->idx < 0)) {
 233                 /* ugh, wrapped! */
 234                 kfree(drv);
 235                 return NULL;
 236         }
 237
 238         /* give it a proper name */
 239         snprintf(drv->wiphy.dev.bus_id, BUS_ID_SIZE,
 240                  PHY_NAME "%d", drv->idx);
 241
 242         mutex_init(&drv->mtx);
 243         mutex_init(&drv->devlist_mtx);
 244         INIT_LIST_HEAD(&drv->netdev_list);
 245
 246         device_initialize(&drv->wiphy.dev);
 247         drv->wiphy.dev.class = &ieee80211_class;
 248         drv->wiphy.dev.platform_data = drv;
 249
 250         return &drv->wiphy;
 251 }
 252 EXPORT_SYMBOL(wiphy_new);
 253
 254 int wiphy_register(struct wiphy *wiphy)
 255 {
 256         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 257         int res;
 258         enum ieee80211_band band;
 259         struct ieee80211_supported_band *sband;
 260         bool have_band = false;
 261         int i;
 262
 263         /* sanity check supported bands/channels */
 264         for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 265                 sband = wiphy->bands[band];
 266                 if (!sband)
 267                         continue;
 268
 269                 sband->band = band;
 270
 271                 if (!sband->n_channels || !sband->n_bitrates) {
 272                         WARN_ON(1);
 273                         return -EINVAL;
 274                 }
 275
 276                 for (i = 0; i < sband->n_channels; i++) {
 277                         sband->channels[i].orig_flags =
 278                                 sband->channels[i].flags;
 279                         sband->channels[i].orig_mag =
 280                                 sband->channels[i].max_antenna_gain;
 281                         sband->channels[i].orig_mpwr =
 282                                 sband->channels[i].max_power;
 283                         sband->channels[i].band = band;
 284                 }
 285
 286                 have_band = true;
 287         }
 288
 289         if (!have_band) {
 290                 WARN_ON(1);
 291                 return -EINVAL;
 292         }
 293
 294         /* check and set up bitrates */
 295         ieee80211_set_bitrate_flags(wiphy);
 296
 297         /* set up regulatory info */
 298         wiphy_update_regulatory(wiphy);
 299
 300         mutex_lock(&cfg80211_drv_mutex);
 301
 302         res = device_add(&drv->wiphy.dev);
 303         if (res)
 304                 goto out_unlock;
 305
 306         list_add(&drv->list, &cfg80211_drv_list);
 307
 308         /* add to debugfs */
 309         drv->wiphy.debugfsdir =
 310                 debugfs_create_dir(wiphy_name(&drv->wiphy),
 311                                    ieee80211_debugfs_dir);
 312
 313         res = 0;
 314 out_unlock:
 315         mutex_unlock(&cfg80211_drv_mutex);
 316         return res;
 317 }
 318 EXPORT_SYMBOL(wiphy_register);
 319
 320 void wiphy_unregister(struct wiphy *wiphy)
 321 {
 322         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 323
 324         /* protect the device list */
 325         mutex_lock(&cfg80211_drv_mutex);
 326
 327         BUG_ON(!list_empty(&drv->netdev_list));
 328
 329         /*
 330          * Try to grab drv->mtx. If a command is still in progress,
 331          * hopefully the driver will refuse it since it's tearing
 332          * down the device already. We wait for this command to complete
 333          * before unlinking the item from the list.
 334          * Note: as codified by the BUG_ON above we cannot get here if
 335          * a virtual interface is still associated. Hence, we can only
 336          * get to lock contention here if userspace issues a command
 337          * that identified the hardware by wiphy index.
 338          */
 339         mutex_lock(&drv->mtx);
 340         /* unlock again before freeing */
 341         mutex_unlock(&drv->mtx);
 342
 343         list_del(&drv->list);
 344         device_del(&drv->wiphy.dev);
 345         debugfs_remove(drv->wiphy.debugfsdir);
 346
 347         mutex_unlock(&cfg80211_drv_mutex);
 348 }
 349 EXPORT_SYMBOL(wiphy_unregister);
 350
 351 void cfg80211_dev_free(struct cfg80211_registered_device *drv)
 352 {
 353         mutex_destroy(&drv->mtx);
 354         mutex_destroy(&drv->devlist_mtx);
 355         kfree(drv);
 356 }
 357
 358 void wiphy_free(struct wiphy *wiphy)
 359 {
 360         put_device(&wiphy->dev);
 361 }
 362 EXPORT_SYMBOL(wiphy_free);
 363
 364 static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
 365                                          unsigned long state,
 366                                          void *ndev)
 367 {
 368         struct net_device *dev = ndev;
 369         struct cfg80211_registered_device *rdev;
 370
 371         if (!dev->ieee80211_ptr)
 372                 return 0;
 373
 374         rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 375
 376         switch (state) {
 377         case NETDEV_REGISTER:
 378                 mutex_lock(&rdev->devlist_mtx);
 379                 list_add(&dev->ieee80211_ptr->list, &rdev->netdev_list);
 380                 if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
 381                                       "phy80211")) {
 382                         printk(KERN_ERR "wireless: failed to add phy80211 "
 383                                 "symlink to netdev!\n");
 384                 }
 385                 dev->ieee80211_ptr->netdev = dev;
 386                 mutex_unlock(&rdev->devlist_mtx);
 387                 break;
 388         case NETDEV_UNREGISTER:
 389                 mutex_lock(&rdev->devlist_mtx);
 390                 if (!list_empty(&dev->ieee80211_ptr->list)) {
 391                         sysfs_remove_link(&dev->dev.kobj, "phy80211");
 392                         list_del_init(&dev->ieee80211_ptr->list);
 393                 }
 394                 mutex_unlock(&rdev->devlist_mtx);
 395                 break;
 396         }
 397
 398         return 0;
 399 }
 400
 401 static struct notifier_block cfg80211_netdev_notifier = {
 402         .notifier_call = cfg80211_netdev_notifier_call,
 403 };
 404
 405 static int cfg80211_init(void)
 406 {
 407         int err = wiphy_sysfs_init();
 408         if (err)
 409                 goto out_fail_sysfs;
 410
 411         err = register_netdevice_notifier(&cfg80211_netdev_notifier);
 412         if (err)
 413                 goto out_fail_notifier;
 414
 415         err = nl80211_init();
 416         if (err)
 417                 goto out_fail_nl80211;
 418
 419         ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);
 420
 421         return 0;
 422
 423 out_fail_nl80211:
 424         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 425 out_fail_notifier:
 426         wiphy_sysfs_exit();
 427 out_fail_sysfs:
 428         return err;
 429 }
 430 subsys_initcall(cfg80211_init);
 431
 432 static void cfg80211_exit(void)
 433 {
 434         debugfs_remove(ieee80211_debugfs_dir);
 435         nl80211_exit();
 436         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 437         wiphy_sysfs_exit();
 438 }
 439 module_exit(cfg80211_exit);