net/wireless/core.c

   1 /*
   2  * This is the linux wireless configuration interface.
   3  *
   4  * Copyright 2006-2008          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 #include "reg.h"
  23
  24 /* name for sysfs, %d is appended */
  25 #define PHY_NAME "phy"
  26
  27 MODULE_AUTHOR("Johannes Berg");
  28 MODULE_LICENSE("GPL");
  29 MODULE_DESCRIPTION("wireless configuration support");
  30
  31 /* RCU might be appropriate here since we usually
  32  * only read the list, and that can happen quite
  33  * often because we need to do it for each command */
  34 LIST_HEAD(cfg80211_drv_list);
  35 DEFINE_MUTEX(cfg80211_drv_mutex);
  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 (rdev->wiphy.debugfsdir &&
 188             !debugfs_rename(rdev->wiphy.debugfsdir->d_parent,
 189                             rdev->wiphy.debugfsdir,
 190                             rdev->wiphy.debugfsdir->d_parent,
 191                             newname))
 192                 printk(KERN_ERR "cfg80211: failed to rename debugfs dir to %s!\n",
 193                        newname);
 194
 195         result = 0;
 196 out_unlock:
 197         mutex_unlock(&cfg80211_drv_mutex);
 198         if (result == 0)
 199                 nl80211_notify_dev_rename(rdev);
 200
 201         return result;
 202 }
 203
 204 /* exported functions */
 205
 206 struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
 207 {
 208         static int wiphy_counter;
 209
 210         struct cfg80211_registered_device *drv;
 211         int alloc_size;
 212
 213         WARN_ON(!ops->add_key && ops->del_key);
 214         WARN_ON(ops->add_key && !ops->del_key);
 215
 216         alloc_size = sizeof(*drv) + sizeof_priv;
 217
 218         drv = kzalloc(alloc_size, GFP_KERNEL);
 219         if (!drv)
 220                 return NULL;
 221
 222         drv->ops = ops;
 223
 224         mutex_lock(&cfg80211_drv_mutex);
 225
 226         drv->idx = wiphy_counter++;
 227
 228         if (unlikely(drv->idx < 0)) {
 229                 wiphy_counter--;
 230                 mutex_unlock(&cfg80211_drv_mutex);
 231                 /* ugh, wrapped! */
 232                 kfree(drv);
 233                 return NULL;
 234         }
 235
 236         mutex_unlock(&cfg80211_drv_mutex);
 237
 238         /* give it a proper name */
 239         dev_set_name(&drv->wiphy.dev, PHY_NAME "%d", drv->idx);
 240
 241         mutex_init(&drv->mtx);
 242         mutex_init(&drv->devlist_mtx);
 243         INIT_LIST_HEAD(&drv->netdev_list);
 244
 245         device_initialize(&drv->wiphy.dev);
 246         drv->wiphy.dev.class = &ieee80211_class;
 247         drv->wiphy.dev.platform_data = drv;
 248
 249         return &drv->wiphy;
 250 }
 251 EXPORT_SYMBOL(wiphy_new);
 252
 253 int wiphy_register(struct wiphy *wiphy)
 254 {
 255         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 256         int res;
 257         enum ieee80211_band band;
 258         struct ieee80211_supported_band *sband;
 259         bool have_band = false;
 260         int i;
 261         u16 ifmodes = wiphy->interface_modes;
 262
 263         /* sanity check ifmodes */
 264         WARN_ON(!ifmodes);
 265         ifmodes &= ((1 << __NL80211_IFTYPE_AFTER_LAST) - 1) & ~1;
 266         if (WARN_ON(ifmodes != wiphy->interface_modes))
 267                 wiphy->interface_modes = ifmodes;
 268
 269         /* sanity check supported bands/channels */
 270         for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 271                 sband = wiphy->bands[band];
 272                 if (!sband)
 273                         continue;
 274
 275                 sband->band = band;
 276
 277                 if (!sband->n_channels || !sband->n_bitrates) {
 278                         WARN_ON(1);
 279                         return -EINVAL;
 280                 }
 281
 282                 for (i = 0; i < sband->n_channels; i++) {
 283                         sband->channels[i].orig_flags =
 284                                 sband->channels[i].flags;
 285                         sband->channels[i].orig_mag =
 286                                 sband->channels[i].max_antenna_gain;
 287                         sband->channels[i].orig_mpwr =
 288                                 sband->channels[i].max_power;
 289                         sband->channels[i].band = band;
 290                 }
 291
 292                 have_band = true;
 293         }
 294
 295         if (!have_band) {
 296                 WARN_ON(1);
 297                 return -EINVAL;
 298         }
 299
 300         /* check and set up bitrates */
 301         ieee80211_set_bitrate_flags(wiphy);
 302
 303         mutex_lock(&cfg80211_drv_mutex);
 304
 305         /* set up regulatory info */
 306         wiphy_update_regulatory(wiphy, REGDOM_SET_BY_CORE);
 307
 308         res = device_add(&drv->wiphy.dev);
 309         if (res)
 310                 goto out_unlock;
 311
 312         list_add(&drv->list, &cfg80211_drv_list);
 313
 314         /* add to debugfs */
 315         drv->wiphy.debugfsdir =
 316                 debugfs_create_dir(wiphy_name(&drv->wiphy),
 317                                    ieee80211_debugfs_dir);
 318         if (IS_ERR(drv->wiphy.debugfsdir))
 319                 drv->wiphy.debugfsdir = NULL;
 320
 321         res = 0;
 322 out_unlock:
 323         mutex_unlock(&cfg80211_drv_mutex);
 324         return res;
 325 }
 326 EXPORT_SYMBOL(wiphy_register);
 327
 328 void wiphy_unregister(struct wiphy *wiphy)
 329 {
 330         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 331
 332         /* protect the device list */
 333         mutex_lock(&cfg80211_drv_mutex);
 334
 335         BUG_ON(!list_empty(&drv->netdev_list));
 336
 337         /*
 338          * Try to grab drv->mtx. If a command is still in progress,
 339          * hopefully the driver will refuse it since it's tearing
 340          * down the device already. We wait for this command to complete
 341          * before unlinking the item from the list.
 342          * Note: as codified by the BUG_ON above we cannot get here if
 343          * a virtual interface is still associated. Hence, we can only
 344          * get to lock contention here if userspace issues a command
 345          * that identified the hardware by wiphy index.
 346          */
 347         mutex_lock(&drv->mtx);
 348         /* unlock again before freeing */
 349         mutex_unlock(&drv->mtx);
 350
 351         list_del(&drv->list);
 352         device_del(&drv->wiphy.dev);
 353         debugfs_remove(drv->wiphy.debugfsdir);
 354
 355         mutex_unlock(&cfg80211_drv_mutex);
 356 }
 357 EXPORT_SYMBOL(wiphy_unregister);
 358
 359 void cfg80211_dev_free(struct cfg80211_registered_device *drv)
 360 {
 361         mutex_destroy(&drv->mtx);
 362         mutex_destroy(&drv->devlist_mtx);
 363         kfree(drv);
 364 }
 365
 366 void wiphy_free(struct wiphy *wiphy)
 367 {
 368         put_device(&wiphy->dev);
 369 }
 370 EXPORT_SYMBOL(wiphy_free);
 371
 372 static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
 373                                          unsigned long state,
 374                                          void *ndev)
 375 {
 376         struct net_device *dev = ndev;
 377         struct cfg80211_registered_device *rdev;
 378
 379         if (!dev->ieee80211_ptr)
 380                 return 0;
 381
 382         rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 383
 384         WARN_ON(dev->ieee80211_ptr->iftype == NL80211_IFTYPE_UNSPECIFIED);
 385
 386         switch (state) {
 387         case NETDEV_REGISTER:
 388                 mutex_lock(&rdev->devlist_mtx);
 389                 list_add(&dev->ieee80211_ptr->list, &rdev->netdev_list);
 390                 if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
 391                                       "phy80211")) {
 392                         printk(KERN_ERR "wireless: failed to add phy80211 "
 393                                 "symlink to netdev!\n");
 394                 }
 395                 dev->ieee80211_ptr->netdev = dev;
 396                 mutex_unlock(&rdev->devlist_mtx);
 397                 break;
 398         case NETDEV_UNREGISTER:
 399                 mutex_lock(&rdev->devlist_mtx);
 400                 if (!list_empty(&dev->ieee80211_ptr->list)) {
 401                         sysfs_remove_link(&dev->dev.kobj, "phy80211");
 402                         list_del_init(&dev->ieee80211_ptr->list);
 403                 }
 404                 mutex_unlock(&rdev->devlist_mtx);
 405                 break;
 406         }
 407
 408         return 0;
 409 }
 410
 411 static struct notifier_block cfg80211_netdev_notifier = {
 412         .notifier_call = cfg80211_netdev_notifier_call,
 413 };
 414
 415 static int cfg80211_init(void)
 416 {
 417         int err;
 418
 419         err = wiphy_sysfs_init();
 420         if (err)
 421                 goto out_fail_sysfs;
 422
 423         err = register_netdevice_notifier(&cfg80211_netdev_notifier);
 424         if (err)
 425                 goto out_fail_notifier;
 426
 427         err = nl80211_init();
 428         if (err)
 429                 goto out_fail_nl80211;
 430
 431         ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);
 432
 433         err = regulatory_init();
 434         if (err)
 435                 goto out_fail_reg;
 436
 437         return 0;
 438
 439 out_fail_reg:
 440         debugfs_remove(ieee80211_debugfs_dir);
 441 out_fail_nl80211:
 442         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 443 out_fail_notifier:
 444         wiphy_sysfs_exit();
 445 out_fail_sysfs:
 446         return err;
 447 }
 448
 449 subsys_initcall(cfg80211_init);
 450
 451 static void cfg80211_exit(void)
 452 {
 453         debugfs_remove(ieee80211_debugfs_dir);
 454         nl80211_exit();
 455         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 456         wiphy_sysfs_exit();
 457         regulatory_exit();
 458 }
 459 module_exit(cfg80211_exit);