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 <linux/list.h>
  17 #include <net/genetlink.h>
  18 #include <net/cfg80211.h>
  19 #include <net/wireless.h>
  20 #include "nl80211.h"
  21 #include "core.h"
  22 #include "sysfs.h"
  23 #include "reg.h"
  24
  25 /* name for sysfs, %d is appended */
  26 #define PHY_NAME "phy"
  27
  28 MODULE_AUTHOR("Johannes Berg");
  29 MODULE_LICENSE("GPL");
  30 MODULE_DESCRIPTION("wireless configuration support");
  31
  32 /* RCU might be appropriate here since we usually
  33  * only read the list, and that can happen quite
  34  * often because we need to do it for each command */
  35 LIST_HEAD(cfg80211_drv_list);
  36 DEFINE_MUTEX(cfg80211_drv_mutex);
  37
  38 /* for debugfs */
  39 static struct dentry *ieee80211_debugfs_dir;
  40
  41 /* requires cfg80211_drv_mutex to be held! */
  42 static struct cfg80211_registered_device *cfg80211_drv_by_wiphy(int wiphy)
  43 {
  44         struct cfg80211_registered_device *result = NULL, *drv;
  45
  46         list_for_each_entry(drv, &cfg80211_drv_list, list) {
  47                 if (drv->idx == wiphy) {
  48                         result = drv;
  49                         break;
  50                 }
  51         }
  52
  53         return result;
  54 }
  55
  56 /* requires cfg80211_drv_mutex to be held! */
  57 static struct cfg80211_registered_device *
  58 __cfg80211_drv_from_info(struct genl_info *info)
  59 {
  60         int ifindex;
  61         struct cfg80211_registered_device *bywiphy = NULL, *byifidx = NULL;
  62         struct net_device *dev;
  63         int err = -EINVAL;
  64
  65         if (info->attrs[NL80211_ATTR_WIPHY]) {
  66                 bywiphy = cfg80211_drv_by_wiphy(
  67                                 nla_get_u32(info->attrs[NL80211_ATTR_WIPHY]));
  68                 err = -ENODEV;
  69         }
  70
  71         if (info->attrs[NL80211_ATTR_IFINDEX]) {
  72                 ifindex = nla_get_u32(info->attrs[NL80211_ATTR_IFINDEX]);
  73                 dev = dev_get_by_index(&init_net, ifindex);
  74                 if (dev) {
  75                         if (dev->ieee80211_ptr)
  76                                 byifidx =
  77                                         wiphy_to_dev(dev->ieee80211_ptr->wiphy);
  78                         dev_put(dev);
  79                 }
  80                 err = -ENODEV;
  81         }
  82
  83         if (bywiphy && byifidx) {
  84                 if (bywiphy != byifidx)
  85                         return ERR_PTR(-EINVAL);
  86                 else
  87                         return bywiphy; /* == byifidx */
  88         }
  89         if (bywiphy)
  90                 return bywiphy;
  91
  92         if (byifidx)
  93                 return byifidx;
  94
  95         return ERR_PTR(err);
  96 }
  97
  98 struct cfg80211_registered_device *
  99 cfg80211_get_dev_from_info(struct genl_info *info)
 100 {
 101         struct cfg80211_registered_device *drv;
 102
 103         mutex_lock(&cfg80211_drv_mutex);
 104         drv = __cfg80211_drv_from_info(info);
 105
 106         /* if it is not an error we grab the lock on
 107          * it to assure it won't be going away while
 108          * we operate on it */
 109         if (!IS_ERR(drv))
 110                 mutex_lock(&drv->mtx);
 111
 112         mutex_unlock(&cfg80211_drv_mutex);
 113
 114         return drv;
 115 }
 116
 117 struct cfg80211_registered_device *
 118 cfg80211_get_dev_from_ifindex(int ifindex)
 119 {
 120         struct cfg80211_registered_device *drv = ERR_PTR(-ENODEV);
 121         struct net_device *dev;
 122
 123         mutex_lock(&cfg80211_drv_mutex);
 124         dev = dev_get_by_index(&init_net, ifindex);
 125         if (!dev)
 126                 goto out;
 127         if (dev->ieee80211_ptr) {
 128                 drv = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 129                 mutex_lock(&drv->mtx);
 130         } else
 131                 drv = ERR_PTR(-ENODEV);
 132         dev_put(dev);
 133  out:
 134         mutex_unlock(&cfg80211_drv_mutex);
 135         return drv;
 136 }
 137
 138 void cfg80211_put_dev(struct cfg80211_registered_device *drv)
 139 {
 140         BUG_ON(IS_ERR(drv));
 141         mutex_unlock(&drv->mtx);
 142 }
 143
 144 int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
 145                         char *newname)
 146 {
 147         struct cfg80211_registered_device *drv;
 148         int idx, taken = -1, result, digits;
 149
 150         mutex_lock(&cfg80211_drv_mutex);
 151
 152         /* prohibit calling the thing phy%d when %d is not its number */
 153         sscanf(newname, PHY_NAME "%d%n", &idx, &taken);
 154         if (taken == strlen(newname) && idx != rdev->idx) {
 155                 /* count number of places needed to print idx */
 156                 digits = 1;
 157                 while (idx /= 10)
 158                         digits++;
 159                 /*
 160                  * deny the name if it is phy<idx> where <idx> is printed
 161                  * without leading zeroes. taken == strlen(newname) here
 162                  */
 163                 result = -EINVAL;
 164                 if (taken == strlen(PHY_NAME) + digits)
 165                         goto out_unlock;
 166         }
 167
 168
 169         /* Ignore nop renames */
 170         result = 0;
 171         if (strcmp(newname, dev_name(&rdev->wiphy.dev)) == 0)
 172                 goto out_unlock;
 173
 174         /* Ensure another device does not already have this name. */
 175         list_for_each_entry(drv, &cfg80211_drv_list, list) {
 176                 result = -EINVAL;
 177                 if (strcmp(newname, dev_name(&drv->wiphy.dev)) == 0)
 178                         goto out_unlock;
 179         }
 180
 181         /* this will only check for collisions in sysfs
 182          * which is not even always compiled in.
 183          */
 184         result = device_rename(&rdev->wiphy.dev, newname);
 185         if (result)
 186                 goto out_unlock;
 187
 188         if (!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         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         u16 ifmodes = wiphy->interface_modes;
 263
 264         /* sanity check ifmodes */
 265         WARN_ON(!ifmodes);
 266         ifmodes &= ((1 << __NL80211_IFTYPE_AFTER_LAST) - 1) & ~1;
 267         if (WARN_ON(ifmodes != wiphy->interface_modes))
 268                 wiphy->interface_modes = ifmodes;
 269
 270         /* sanity check supported bands/channels */
 271         for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 272                 sband = wiphy->bands[band];
 273                 if (!sband)
 274                         continue;
 275
 276                 sband->band = band;
 277
 278                 if (!sband->n_channels || !sband->n_bitrates) {
 279                         WARN_ON(1);
 280                         return -EINVAL;
 281                 }
 282
 283                 for (i = 0; i < sband->n_channels; i++) {
 284                         sband->channels[i].orig_flags =
 285                                 sband->channels[i].flags;
 286                         sband->channels[i].orig_mag =
 287                                 sband->channels[i].max_antenna_gain;
 288                         sband->channels[i].orig_mpwr =
 289                                 sband->channels[i].max_power;
 290                         sband->channels[i].band = band;
 291                 }
 292
 293                 have_band = true;
 294         }
 295
 296         if (!have_band) {
 297                 WARN_ON(1);
 298                 return -EINVAL;
 299         }
 300
 301         /* check and set up bitrates */
 302         ieee80211_set_bitrate_flags(wiphy);
 303
 304         /* set up regulatory info */
 305         mutex_lock(&cfg80211_reg_mutex);
 306         wiphy_update_regulatory(wiphy, REGDOM_SET_BY_CORE);
 307         mutex_unlock(&cfg80211_reg_mutex);
 308
 309         mutex_lock(&cfg80211_drv_mutex);
 310
 311         res = device_add(&drv->wiphy.dev);
 312         if (res)
 313                 goto out_unlock;
 314
 315         list_add(&drv->list, &cfg80211_drv_list);
 316
 317         /* add to debugfs */
 318         drv->wiphy.debugfsdir =
 319                 debugfs_create_dir(wiphy_name(&drv->wiphy),
 320                                    ieee80211_debugfs_dir);
 321
 322         res = 0;
 323 out_unlock:
 324         mutex_unlock(&cfg80211_drv_mutex);
 325         return res;
 326 }
 327 EXPORT_SYMBOL(wiphy_register);
 328
 329 void wiphy_unregister(struct wiphy *wiphy)
 330 {
 331         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 332
 333         /* protect the device list */
 334         mutex_lock(&cfg80211_drv_mutex);
 335
 336         BUG_ON(!list_empty(&drv->netdev_list));
 337
 338         /*
 339          * Try to grab drv->mtx. If a command is still in progress,
 340          * hopefully the driver will refuse it since it's tearing
 341          * down the device already. We wait for this command to complete
 342          * before unlinking the item from the list.
 343          * Note: as codified by the BUG_ON above we cannot get here if
 344          * a virtual interface is still associated. Hence, we can only
 345          * get to lock contention here if userspace issues a command
 346          * that identified the hardware by wiphy index.
 347          */
 348         mutex_lock(&drv->mtx);
 349         /* unlock again before freeing */
 350         mutex_unlock(&drv->mtx);
 351
 352         list_del(&drv->list);
 353         device_del(&drv->wiphy.dev);
 354         debugfs_remove(drv->wiphy.debugfsdir);
 355
 356         mutex_unlock(&cfg80211_drv_mutex);
 357 }
 358 EXPORT_SYMBOL(wiphy_unregister);
 359
 360 void cfg80211_dev_free(struct cfg80211_registered_device *drv)
 361 {
 362         mutex_destroy(&drv->mtx);
 363         mutex_destroy(&drv->devlist_mtx);
 364         kfree(drv);
 365 }
 366
 367 void wiphy_free(struct wiphy *wiphy)
 368 {
 369         put_device(&wiphy->dev);
 370 }
 371 EXPORT_SYMBOL(wiphy_free);
 372
 373 static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
 374                                          unsigned long state,
 375                                          void *ndev)
 376 {
 377         struct net_device *dev = ndev;
 378         struct cfg80211_registered_device *rdev;
 379
 380         if (!dev->ieee80211_ptr)
 381                 return 0;
 382
 383         rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 384
 385         WARN_ON(dev->ieee80211_ptr->iftype == NL80211_IFTYPE_UNSPECIFIED);
 386
 387         switch (state) {
 388         case NETDEV_REGISTER:
 389                 mutex_lock(&rdev->devlist_mtx);
 390                 list_add(&dev->ieee80211_ptr->list, &rdev->netdev_list);
 391                 if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
 392                                       "phy80211")) {
 393                         printk(KERN_ERR "wireless: failed to add phy80211 "
 394                                 "symlink to netdev!\n");
 395                 }
 396                 dev->ieee80211_ptr->netdev = dev;
 397                 mutex_unlock(&rdev->devlist_mtx);
 398                 break;
 399         case NETDEV_UNREGISTER:
 400                 mutex_lock(&rdev->devlist_mtx);
 401                 if (!list_empty(&dev->ieee80211_ptr->list)) {
 402                         sysfs_remove_link(&dev->dev.kobj, "phy80211");
 403                         list_del_init(&dev->ieee80211_ptr->list);
 404                 }
 405                 mutex_unlock(&rdev->devlist_mtx);
 406                 break;
 407         }
 408
 409         return 0;
 410 }
 411
 412 static struct notifier_block cfg80211_netdev_notifier = {
 413         .notifier_call = cfg80211_netdev_notifier_call,
 414 };
 415
 416 static int cfg80211_init(void)
 417 {
 418         int err;
 419
 420         err = wiphy_sysfs_init();
 421         if (err)
 422                 goto out_fail_sysfs;
 423
 424         err = register_netdevice_notifier(&cfg80211_netdev_notifier);
 425         if (err)
 426                 goto out_fail_notifier;
 427
 428         err = nl80211_init();
 429         if (err)
 430                 goto out_fail_nl80211;
 431
 432         ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);
 433
 434         err = regulatory_init();
 435         if (err)
 436                 goto out_fail_reg;
 437
 438         return 0;
 439
 440 out_fail_reg:
 441         debugfs_remove(ieee80211_debugfs_dir);
 442 out_fail_nl80211:
 443         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 444 out_fail_notifier:
 445         wiphy_sysfs_exit();
 446 out_fail_sysfs:
 447         return err;
 448 }
 449
 450 subsys_initcall(cfg80211_init);
 451
 452 static void cfg80211_exit(void)
 453 {
 454         debugfs_remove(ieee80211_debugfs_dir);
 455         nl80211_exit();
 456         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 457         wiphy_sysfs_exit();
 458         regulatory_exit();
 459 }
 460 module_exit(cfg80211_exit);