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 static int wiphy_counter;
  38
  39 /* for debugfs */
  40 static struct dentry *ieee80211_debugfs_dir;
  41
  42 /* requires cfg80211_drv_mutex to be held! */
  43 static struct cfg80211_registered_device *cfg80211_drv_by_wiphy(int wiphy)
  44 {
  45         struct cfg80211_registered_device *result = NULL, *drv;
  46
  47         list_for_each_entry(drv, &cfg80211_drv_list, list) {
  48                 if (drv->idx == wiphy) {
  49                         result = drv;
  50                         break;
  51                 }
  52         }
  53
  54         return result;
  55 }
  56
  57 /* requires cfg80211_drv_mutex to be held! */
  58 static struct cfg80211_registered_device *
  59 __cfg80211_drv_from_info(struct genl_info *info)
  60 {
  61         int ifindex;
  62         struct cfg80211_registered_device *bywiphy = NULL, *byifidx = NULL;
  63         struct net_device *dev;
  64         int err = -EINVAL;
  65
  66         if (info->attrs[NL80211_ATTR_WIPHY]) {
  67                 bywiphy = cfg80211_drv_by_wiphy(
  68                                 nla_get_u32(info->attrs[NL80211_ATTR_WIPHY]));
  69                 err = -ENODEV;
  70         }
  71
  72         if (info->attrs[NL80211_ATTR_IFINDEX]) {
  73                 ifindex = nla_get_u32(info->attrs[NL80211_ATTR_IFINDEX]);
  74                 dev = dev_get_by_index(&init_net, ifindex);
  75                 if (dev) {
  76                         if (dev->ieee80211_ptr)
  77                                 byifidx =
  78                                         wiphy_to_dev(dev->ieee80211_ptr->wiphy);
  79                         dev_put(dev);
  80                 }
  81                 err = -ENODEV;
  82         }
  83
  84         if (bywiphy && byifidx) {
  85                 if (bywiphy != byifidx)
  86                         return ERR_PTR(-EINVAL);
  87                 else
  88                         return bywiphy; /* == byifidx */
  89         }
  90         if (bywiphy)
  91                 return bywiphy;
  92
  93         if (byifidx)
  94                 return byifidx;
  95
  96         return ERR_PTR(err);
  97 }
  98
  99 struct cfg80211_registered_device *
 100 cfg80211_get_dev_from_info(struct genl_info *info)
 101 {
 102         struct cfg80211_registered_device *drv;
 103
 104         mutex_lock(&cfg80211_drv_mutex);
 105         drv = __cfg80211_drv_from_info(info);
 106
 107         /* if it is not an error we grab the lock on
 108          * it to assure it won't be going away while
 109          * we operate on it */
 110         if (!IS_ERR(drv))
 111                 mutex_lock(&drv->mtx);
 112
 113         mutex_unlock(&cfg80211_drv_mutex);
 114
 115         return drv;
 116 }
 117
 118 struct cfg80211_registered_device *
 119 cfg80211_get_dev_from_ifindex(int ifindex)
 120 {
 121         struct cfg80211_registered_device *drv = ERR_PTR(-ENODEV);
 122         struct net_device *dev;
 123
 124         mutex_lock(&cfg80211_drv_mutex);
 125         dev = dev_get_by_index(&init_net, ifindex);
 126         if (!dev)
 127                 goto out;
 128         if (dev->ieee80211_ptr) {
 129                 drv = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 130                 mutex_lock(&drv->mtx);
 131         } else
 132                 drv = ERR_PTR(-ENODEV);
 133         dev_put(dev);
 134  out:
 135         mutex_unlock(&cfg80211_drv_mutex);
 136         return drv;
 137 }
 138
 139 void cfg80211_put_dev(struct cfg80211_registered_device *drv)
 140 {
 141         BUG_ON(IS_ERR(drv));
 142         mutex_unlock(&drv->mtx);
 143 }
 144
 145 int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
 146                         char *newname)
 147 {
 148         struct cfg80211_registered_device *drv;
 149         int idx, taken = -1, result, digits;
 150
 151         mutex_lock(&cfg80211_drv_mutex);
 152
 153         /* prohibit calling the thing phy%d when %d is not its number */
 154         sscanf(newname, PHY_NAME "%d%n", &idx, &taken);
 155         if (taken == strlen(newname) && idx != rdev->idx) {
 156                 /* count number of places needed to print idx */
 157                 digits = 1;
 158                 while (idx /= 10)
 159                         digits++;
 160                 /*
 161                  * deny the name if it is phy<idx> where <idx> is printed
 162                  * without leading zeroes. taken == strlen(newname) here
 163                  */
 164                 result = -EINVAL;
 165                 if (taken == strlen(PHY_NAME) + digits)
 166                         goto out_unlock;
 167         }
 168
 169
 170         /* Ignore nop renames */
 171         result = 0;
 172         if (strcmp(newname, dev_name(&rdev->wiphy.dev)) == 0)
 173                 goto out_unlock;
 174
 175         /* Ensure another device does not already have this name. */
 176         list_for_each_entry(drv, &cfg80211_drv_list, list) {
 177                 result = -EINVAL;
 178                 if (strcmp(newname, dev_name(&drv->wiphy.dev)) == 0)
 179                         goto out_unlock;
 180         }
 181
 182         /* this will only check for collisions in sysfs
 183          * which is not even always compiled in.
 184          */
 185         result = device_rename(&rdev->wiphy.dev, newname);
 186         if (result)
 187                 goto out_unlock;
 188
 189         if (!debugfs_rename(rdev->wiphy.debugfsdir->d_parent,
 190                             rdev->wiphy.debugfsdir,
 191                             rdev->wiphy.debugfsdir->d_parent,
 192                             newname))
 193                 printk(KERN_ERR "cfg80211: failed to rename debugfs dir to %s!\n",
 194                        newname);
 195
 196         result = 0;
 197 out_unlock:
 198         mutex_unlock(&cfg80211_drv_mutex);
 199         if (result == 0)
 200                 nl80211_notify_dev_rename(rdev);
 201
 202         return result;
 203 }
 204
 205 /* exported functions */
 206
 207 struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
 208 {
 209         struct cfg80211_registered_device *drv;
 210         int alloc_size;
 211
 212         WARN_ON(!ops->add_key && ops->del_key);
 213         WARN_ON(ops->add_key && !ops->del_key);
 214
 215         alloc_size = sizeof(*drv) + sizeof_priv;
 216
 217         drv = kzalloc(alloc_size, GFP_KERNEL);
 218         if (!drv)
 219                 return NULL;
 220
 221         drv->ops = ops;
 222
 223         mutex_lock(&cfg80211_drv_mutex);
 224
 225         drv->idx = wiphy_counter;
 226
 227         /* now increase counter for the next device unless
 228          * it has wrapped previously */
 229         if (wiphy_counter >= 0)
 230                 wiphy_counter++;
 231
 232         mutex_unlock(&cfg80211_drv_mutex);
 233
 234         if (unlikely(drv->idx < 0)) {
 235                 /* ugh, wrapped! */
 236                 kfree(drv);
 237                 return NULL;
 238         }
 239
 240         /* give it a proper name */
 241         snprintf(drv->wiphy.dev.bus_id, BUS_ID_SIZE,
 242                  PHY_NAME "%d", drv->idx);
 243
 244         mutex_init(&drv->mtx);
 245         mutex_init(&drv->devlist_mtx);
 246         INIT_LIST_HEAD(&drv->netdev_list);
 247
 248         device_initialize(&drv->wiphy.dev);
 249         drv->wiphy.dev.class = &ieee80211_class;
 250         drv->wiphy.dev.platform_data = drv;
 251
 252         return &drv->wiphy;
 253 }
 254 EXPORT_SYMBOL(wiphy_new);
 255
 256 int wiphy_register(struct wiphy *wiphy)
 257 {
 258         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 259         int res;
 260         enum ieee80211_band band;
 261         struct ieee80211_supported_band *sband;
 262         bool have_band = false;
 263         int i;
 264         u16 ifmodes = wiphy->interface_modes;
 265
 266         /* sanity check ifmodes */
 267         WARN_ON(!ifmodes);
 268         ifmodes &= ((1 << __NL80211_IFTYPE_AFTER_LAST) - 1) & ~1;
 269         if (WARN_ON(ifmodes != wiphy->interface_modes))
 270                 wiphy->interface_modes = ifmodes;
 271
 272         /* sanity check supported bands/channels */
 273         for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 274                 sband = wiphy->bands[band];
 275                 if (!sband)
 276                         continue;
 277
 278                 sband->band = band;
 279
 280                 if (!sband->n_channels || !sband->n_bitrates) {
 281                         WARN_ON(1);
 282                         return -EINVAL;
 283                 }
 284
 285                 for (i = 0; i < sband->n_channels; i++) {
 286                         sband->channels[i].orig_flags =
 287                                 sband->channels[i].flags;
 288                         sband->channels[i].orig_mag =
 289                                 sband->channels[i].max_antenna_gain;
 290                         sband->channels[i].orig_mpwr =
 291                                 sband->channels[i].max_power;
 292                         sband->channels[i].band = band;
 293                 }
 294
 295                 have_band = true;
 296         }
 297
 298         if (!have_band) {
 299                 WARN_ON(1);
 300                 return -EINVAL;
 301         }
 302
 303         /* check and set up bitrates */
 304         ieee80211_set_bitrate_flags(wiphy);
 305
 306         /* set up regulatory info */
 307         mutex_lock(&cfg80211_reg_mutex);
 308         wiphy_update_regulatory(wiphy, REGDOM_SET_BY_CORE);
 309         mutex_unlock(&cfg80211_reg_mutex);
 310
 311         mutex_lock(&cfg80211_drv_mutex);
 312
 313         res = device_add(&drv->wiphy.dev);
 314         if (res)
 315                 goto out_unlock;
 316
 317         list_add(&drv->list, &cfg80211_drv_list);
 318
 319         /* add to debugfs */
 320         drv->wiphy.debugfsdir =
 321                 debugfs_create_dir(wiphy_name(&drv->wiphy),
 322                                    ieee80211_debugfs_dir);
 323
 324         res = 0;
 325 out_unlock:
 326         mutex_unlock(&cfg80211_drv_mutex);
 327         return res;
 328 }
 329 EXPORT_SYMBOL(wiphy_register);
 330
 331 void wiphy_unregister(struct wiphy *wiphy)
 332 {
 333         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 334
 335         /* protect the device list */
 336         mutex_lock(&cfg80211_drv_mutex);
 337
 338         BUG_ON(!list_empty(&drv->netdev_list));
 339
 340         /*
 341          * Try to grab drv->mtx. If a command is still in progress,
 342          * hopefully the driver will refuse it since it's tearing
 343          * down the device already. We wait for this command to complete
 344          * before unlinking the item from the list.
 345          * Note: as codified by the BUG_ON above we cannot get here if
 346          * a virtual interface is still associated. Hence, we can only
 347          * get to lock contention here if userspace issues a command
 348          * that identified the hardware by wiphy index.
 349          */
 350         mutex_lock(&drv->mtx);
 351         /* unlock again before freeing */
 352         mutex_unlock(&drv->mtx);
 353
 354         list_del(&drv->list);
 355         device_del(&drv->wiphy.dev);
 356         debugfs_remove(drv->wiphy.debugfsdir);
 357
 358         mutex_unlock(&cfg80211_drv_mutex);
 359 }
 360 EXPORT_SYMBOL(wiphy_unregister);
 361
 362 void cfg80211_dev_free(struct cfg80211_registered_device *drv)
 363 {
 364         mutex_destroy(&drv->mtx);
 365         mutex_destroy(&drv->devlist_mtx);
 366         kfree(drv);
 367 }
 368
 369 void wiphy_free(struct wiphy *wiphy)
 370 {
 371         put_device(&wiphy->dev);
 372 }
 373 EXPORT_SYMBOL(wiphy_free);
 374
 375 static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
 376                                          unsigned long state,
 377                                          void *ndev)
 378 {
 379         struct net_device *dev = ndev;
 380         struct cfg80211_registered_device *rdev;
 381
 382         if (!dev->ieee80211_ptr)
 383                 return 0;
 384
 385         rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 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);