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
  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         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         wiphy_update_regulatory(wiphy);
 306
 307         mutex_lock(&cfg80211_drv_mutex);
 308
 309         res = device_add(&drv->wiphy.dev);
 310         if (res)
 311                 goto out_unlock;
 312
 313         list_add(&drv->list, &cfg80211_drv_list);
 314
 315         /* add to debugfs */
 316         drv->wiphy.debugfsdir =
 317                 debugfs_create_dir(wiphy_name(&drv->wiphy),
 318                                    ieee80211_debugfs_dir);
 319
 320         res = 0;
 321 out_unlock:
 322         mutex_unlock(&cfg80211_drv_mutex);
 323         return res;
 324 }
 325 EXPORT_SYMBOL(wiphy_register);
 326
 327 void wiphy_unregister(struct wiphy *wiphy)
 328 {
 329         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 330
 331         /* protect the device list */
 332         mutex_lock(&cfg80211_drv_mutex);
 333
 334         BUG_ON(!list_empty(&drv->netdev_list));
 335
 336         /*
 337          * Try to grab drv->mtx. If a command is still in progress,
 338          * hopefully the driver will refuse it since it's tearing
 339          * down the device already. We wait for this command to complete
 340          * before unlinking the item from the list.
 341          * Note: as codified by the BUG_ON above we cannot get here if
 342          * a virtual interface is still associated. Hence, we can only
 343          * get to lock contention here if userspace issues a command
 344          * that identified the hardware by wiphy index.
 345          */
 346         mutex_lock(&drv->mtx);
 347         /* unlock again before freeing */
 348         mutex_unlock(&drv->mtx);
 349
 350         list_del(&drv->list);
 351         device_del(&drv->wiphy.dev);
 352         debugfs_remove(drv->wiphy.debugfsdir);
 353
 354         mutex_unlock(&cfg80211_drv_mutex);
 355 }
 356 EXPORT_SYMBOL(wiphy_unregister);
 357
 358 void cfg80211_dev_free(struct cfg80211_registered_device *drv)
 359 {
 360         mutex_destroy(&drv->mtx);
 361         mutex_destroy(&drv->devlist_mtx);
 362         kfree(drv);
 363 }
 364
 365 void wiphy_free(struct wiphy *wiphy)
 366 {
 367         put_device(&wiphy->dev);
 368 }
 369 EXPORT_SYMBOL(wiphy_free);
 370
 371 static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
 372                                          unsigned long state,
 373                                          void *ndev)
 374 {
 375         struct net_device *dev = ndev;
 376         struct cfg80211_registered_device *rdev;
 377
 378         if (!dev->ieee80211_ptr)
 379                 return 0;
 380
 381         rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 382
 383         switch (state) {
 384         case NETDEV_REGISTER:
 385                 mutex_lock(&rdev->devlist_mtx);
 386                 list_add(&dev->ieee80211_ptr->list, &rdev->netdev_list);
 387                 if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
 388                                       "phy80211")) {
 389                         printk(KERN_ERR "wireless: failed to add phy80211 "
 390                                 "symlink to netdev!\n");
 391                 }
 392                 dev->ieee80211_ptr->netdev = dev;
 393                 mutex_unlock(&rdev->devlist_mtx);
 394                 break;
 395         case NETDEV_UNREGISTER:
 396                 mutex_lock(&rdev->devlist_mtx);
 397                 if (!list_empty(&dev->ieee80211_ptr->list)) {
 398                         sysfs_remove_link(&dev->dev.kobj, "phy80211");
 399                         list_del_init(&dev->ieee80211_ptr->list);
 400                 }
 401                 mutex_unlock(&rdev->devlist_mtx);
 402                 break;
 403         }
 404
 405         return 0;
 406 }
 407
 408 static struct notifier_block cfg80211_netdev_notifier = {
 409         .notifier_call = cfg80211_netdev_notifier_call,
 410 };
 411
 412 static int cfg80211_init(void)
 413 {
 414         int err = wiphy_sysfs_init();
 415         if (err)
 416                 goto out_fail_sysfs;
 417
 418         err = register_netdevice_notifier(&cfg80211_netdev_notifier);
 419         if (err)
 420                 goto out_fail_notifier;
 421
 422         err = nl80211_init();
 423         if (err)
 424                 goto out_fail_nl80211;
 425
 426         ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);
 427
 428         return 0;
 429
 430 out_fail_nl80211:
 431         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 432 out_fail_notifier:
 433         wiphy_sysfs_exit();
 434 out_fail_sysfs:
 435         return err;
 436 }
 437 subsys_initcall(cfg80211_init);
 438
 439 static void cfg80211_exit(void)
 440 {
 441         debugfs_remove(ieee80211_debugfs_dir);
 442         nl80211_exit();
 443         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 444         wiphy_sysfs_exit();
 445 }
 446 module_exit(cfg80211_exit);