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
  36 /* for debugfs */
  37 static struct dentry *ieee80211_debugfs_dir;
  38
  39 /* requires cfg80211_drv_mutex to be held! */
  40 static struct cfg80211_registered_device *cfg80211_drv_by_wiphy(int wiphy)
  41 {
  42         struct cfg80211_registered_device *result = NULL, *drv;
  43
  44         list_for_each_entry(drv, &cfg80211_drv_list, list) {
  45                 if (drv->idx == wiphy) {
  46                         result = drv;
  47                         break;
  48                 }
  49         }
  50
  51         return result;
  52 }
  53
  54 /* requires cfg80211_drv_mutex to be held! */
  55 static struct cfg80211_registered_device *
  56 __cfg80211_drv_from_info(struct genl_info *info)
  57 {
  58         int ifindex;
  59         struct cfg80211_registered_device *bywiphy = NULL, *byifidx = NULL;
  60         struct net_device *dev;
  61         int err = -EINVAL;
  62
  63         if (info->attrs[NL80211_ATTR_WIPHY]) {
  64                 bywiphy = cfg80211_drv_by_wiphy(
  65                                 nla_get_u32(info->attrs[NL80211_ATTR_WIPHY]));
  66                 err = -ENODEV;
  67         }
  68
  69         if (info->attrs[NL80211_ATTR_IFINDEX]) {
  70                 ifindex = nla_get_u32(info->attrs[NL80211_ATTR_IFINDEX]);
  71                 dev = dev_get_by_index(&init_net, ifindex);
  72                 if (dev) {
  73                         if (dev->ieee80211_ptr)
  74                                 byifidx =
  75                                         wiphy_to_dev(dev->ieee80211_ptr->wiphy);
  76                         dev_put(dev);
  77                 }
  78                 err = -ENODEV;
  79         }
  80
  81         if (bywiphy && byifidx) {
  82                 if (bywiphy != byifidx)
  83                         return ERR_PTR(-EINVAL);
  84                 else
  85                         return bywiphy; /* == byifidx */
  86         }
  87         if (bywiphy)
  88                 return bywiphy;
  89
  90         if (byifidx)
  91                 return byifidx;
  92
  93         return ERR_PTR(err);
  94 }
  95
  96 struct cfg80211_registered_device *
  97 cfg80211_get_dev_from_info(struct genl_info *info)
  98 {
  99         struct cfg80211_registered_device *drv;
 100
 101         mutex_lock(&cfg80211_drv_mutex);
 102         drv = __cfg80211_drv_from_info(info);
 103
 104         /* if it is not an error we grab the lock on
 105          * it to assure it won't be going away while
 106          * we operate on it */
 107         if (!IS_ERR(drv))
 108                 mutex_lock(&drv->mtx);
 109
 110         mutex_unlock(&cfg80211_drv_mutex);
 111
 112         return drv;
 113 }
 114
 115 struct cfg80211_registered_device *
 116 cfg80211_get_dev_from_ifindex(int ifindex)
 117 {
 118         struct cfg80211_registered_device *drv = ERR_PTR(-ENODEV);
 119         struct net_device *dev;
 120
 121         mutex_lock(&cfg80211_drv_mutex);
 122         dev = dev_get_by_index(&init_net, ifindex);
 123         if (!dev)
 124                 goto out;
 125         if (dev->ieee80211_ptr) {
 126                 drv = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 127                 mutex_lock(&drv->mtx);
 128         } else
 129                 drv = ERR_PTR(-ENODEV);
 130         dev_put(dev);
 131  out:
 132         mutex_unlock(&cfg80211_drv_mutex);
 133         return drv;
 134 }
 135
 136 void cfg80211_put_dev(struct cfg80211_registered_device *drv)
 137 {
 138         BUG_ON(IS_ERR(drv));
 139         mutex_unlock(&drv->mtx);
 140 }
 141
 142 int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
 143                         char *newname)
 144 {
 145         struct cfg80211_registered_device *drv;
 146         int idx, taken = -1, result, digits;
 147
 148         mutex_lock(&cfg80211_drv_mutex);
 149
 150         /* prohibit calling the thing phy%d when %d is not its number */
 151         sscanf(newname, PHY_NAME "%d%n", &idx, &taken);
 152         if (taken == strlen(newname) && idx != rdev->idx) {
 153                 /* count number of places needed to print idx */
 154                 digits = 1;
 155                 while (idx /= 10)
 156                         digits++;
 157                 /*
 158                  * deny the name if it is phy<idx> where <idx> is printed
 159                  * without leading zeroes. taken == strlen(newname) here
 160                  */
 161                 result = -EINVAL;
 162                 if (taken == strlen(PHY_NAME) + digits)
 163                         goto out_unlock;
 164         }
 165
 166
 167         /* Ignore nop renames */
 168         result = 0;
 169         if (strcmp(newname, dev_name(&rdev->wiphy.dev)) == 0)
 170                 goto out_unlock;
 171
 172         /* Ensure another device does not already have this name. */
 173         list_for_each_entry(drv, &cfg80211_drv_list, list) {
 174                 result = -EINVAL;
 175                 if (strcmp(newname, dev_name(&drv->wiphy.dev)) == 0)
 176                         goto out_unlock;
 177         }
 178
 179         /* this will only check for collisions in sysfs
 180          * which is not even always compiled in.
 181          */
 182         result = device_rename(&rdev->wiphy.dev, newname);
 183         if (result)
 184                 goto out_unlock;
 185
 186         if (rdev->wiphy.debugfsdir &&
 187             !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         static int wiphy_counter;
 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         if (unlikely(drv->idx < 0)) {
 228                 wiphy_counter--;
 229                 mutex_unlock(&cfg80211_drv_mutex);
 230                 /* ugh, wrapped! */
 231                 kfree(drv);
 232                 return NULL;
 233         }
 234
 235         mutex_unlock(&cfg80211_drv_mutex);
 236
 237         /* give it a proper name */
 238         dev_set_name(&drv->wiphy.dev, PHY_NAME "%d", drv->idx);
 239
 240         mutex_init(&drv->mtx);
 241         mutex_init(&drv->devlist_mtx);
 242         INIT_LIST_HEAD(&drv->netdev_list);
 243
 244         device_initialize(&drv->wiphy.dev);
 245         drv->wiphy.dev.class = &ieee80211_class;
 246         drv->wiphy.dev.platform_data = drv;
 247
 248         return &drv->wiphy;
 249 }
 250 EXPORT_SYMBOL(wiphy_new);
 251
 252 int wiphy_register(struct wiphy *wiphy)
 253 {
 254         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 255         int res;
 256         enum ieee80211_band band;
 257         struct ieee80211_supported_band *sband;
 258         bool have_band = false;
 259         int i;
 260         u16 ifmodes = wiphy->interface_modes;
 261
 262         /* sanity check ifmodes */
 263         WARN_ON(!ifmodes);
 264         ifmodes &= ((1 << __NL80211_IFTYPE_AFTER_LAST) - 1) & ~1;
 265         if (WARN_ON(ifmodes != wiphy->interface_modes))
 266                 wiphy->interface_modes = ifmodes;
 267
 268         /* sanity check supported bands/channels */
 269         for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 270                 sband = wiphy->bands[band];
 271                 if (!sband)
 272                         continue;
 273
 274                 sband->band = band;
 275
 276                 if (!sband->n_channels || !sband->n_bitrates) {
 277                         WARN_ON(1);
 278                         return -EINVAL;
 279                 }
 280
 281                 for (i = 0; i < sband->n_channels; i++) {
 282                         sband->channels[i].orig_flags =
 283                                 sband->channels[i].flags;
 284                         sband->channels[i].orig_mag =
 285                                 sband->channels[i].max_antenna_gain;
 286                         sband->channels[i].orig_mpwr =
 287                                 sband->channels[i].max_power;
 288                         sband->channels[i].band = band;
 289                 }
 290
 291                 have_band = true;
 292         }
 293
 294         if (!have_band) {
 295                 WARN_ON(1);
 296                 return -EINVAL;
 297         }
 298
 299         /* check and set up bitrates */
 300         ieee80211_set_bitrate_flags(wiphy);
 301
 302         mutex_lock(&cfg80211_drv_mutex);
 303
 304         /* set up regulatory info */
 305         wiphy_update_regulatory(wiphy, REGDOM_SET_BY_CORE);
 306
 307         res = device_add(&drv->wiphy.dev);
 308         if (res)
 309                 goto out_unlock;
 310
 311         list_add(&drv->list, &cfg80211_drv_list);
 312
 313         /* add to debugfs */
 314         drv->wiphy.debugfsdir =
 315                 debugfs_create_dir(wiphy_name(&drv->wiphy),
 316                                    ieee80211_debugfs_dir);
 317         if (IS_ERR(drv->wiphy.debugfsdir))
 318                 drv->wiphy.debugfsdir = NULL;
 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         /* If this device got a regulatory hint tell core its
 351          * free to listen now to a new shiny device regulatory hint */
 352         reg_device_remove(wiphy);
 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         WARN_ON(dev->ieee80211_ptr->iftype == NL80211_IFTYPE_UNSPECIFIED);
 388
 389         switch (state) {
 390         case NETDEV_REGISTER:
 391                 mutex_lock(&rdev->devlist_mtx);
 392                 list_add(&dev->ieee80211_ptr->list, &rdev->netdev_list);
 393                 if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
 394                                       "phy80211")) {
 395                         printk(KERN_ERR "wireless: failed to add phy80211 "
 396                                 "symlink to netdev!\n");
 397                 }
 398                 dev->ieee80211_ptr->netdev = dev;
 399                 mutex_unlock(&rdev->devlist_mtx);
 400                 break;
 401         case NETDEV_UNREGISTER:
 402                 mutex_lock(&rdev->devlist_mtx);
 403                 if (!list_empty(&dev->ieee80211_ptr->list)) {
 404                         sysfs_remove_link(&dev->dev.kobj, "phy80211");
 405                         list_del_init(&dev->ieee80211_ptr->list);
 406                 }
 407                 mutex_unlock(&rdev->devlist_mtx);
 408                 break;
 409         }
 410
 411         return 0;
 412 }
 413
 414 static struct notifier_block cfg80211_netdev_notifier = {
 415         .notifier_call = cfg80211_netdev_notifier_call,
 416 };
 417
 418 static int cfg80211_init(void)
 419 {
 420         int err;
 421
 422         err = wiphy_sysfs_init();
 423         if (err)
 424                 goto out_fail_sysfs;
 425
 426         err = register_netdevice_notifier(&cfg80211_netdev_notifier);
 427         if (err)
 428                 goto out_fail_notifier;
 429
 430         err = nl80211_init();
 431         if (err)
 432                 goto out_fail_nl80211;
 433
 434         ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);
 435
 436         err = regulatory_init();
 437         if (err)
 438                 goto out_fail_reg;
 439
 440         return 0;
 441
 442 out_fail_reg:
 443         debugfs_remove(ieee80211_debugfs_dir);
 444 out_fail_nl80211:
 445         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 446 out_fail_notifier:
 447         wiphy_sysfs_exit();
 448 out_fail_sysfs:
 449         return err;
 450 }
 451
 452 subsys_initcall(cfg80211_init);
 453
 454 static void cfg80211_exit(void)
 455 {
 456         debugfs_remove(ieee80211_debugfs_dir);
 457         nl80211_exit();
 458         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 459         wiphy_sysfs_exit();
 460         regulatory_exit();
 461 }
 462 module_exit(cfg80211_exit);