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 *
  41 cfg80211_drv_by_wiphy_idx(int wiphy_idx)
  42 {
  43         struct cfg80211_registered_device *result = NULL, *drv;
  44
  45         if (!wiphy_idx_valid(wiphy_idx))
  46                 return NULL;
  47
  48         list_for_each_entry(drv, &cfg80211_drv_list, list) {
  49                 if (drv->wiphy_idx == wiphy_idx) {
  50                         result = drv;
  51                         break;
  52                 }
  53         }
  54
  55         return result;
  56 }
  57
  58 /* requires cfg80211_drv_mutex to be held! */
  59 static struct cfg80211_registered_device *
  60 __cfg80211_drv_from_info(struct genl_info *info)
  61 {
  62         int ifindex;
  63         struct cfg80211_registered_device *bywiphyidx = NULL, *byifidx = NULL;
  64         struct net_device *dev;
  65         int err = -EINVAL;
  66
  67         if (info->attrs[NL80211_ATTR_WIPHY]) {
  68                 bywiphyidx = cfg80211_drv_by_wiphy_idx(
  69                                 nla_get_u32(info->attrs[NL80211_ATTR_WIPHY]));
  70                 err = -ENODEV;
  71         }
  72
  73         if (info->attrs[NL80211_ATTR_IFINDEX]) {
  74                 ifindex = nla_get_u32(info->attrs[NL80211_ATTR_IFINDEX]);
  75                 dev = dev_get_by_index(&init_net, ifindex);
  76                 if (dev) {
  77                         if (dev->ieee80211_ptr)
  78                                 byifidx =
  79                                         wiphy_to_dev(dev->ieee80211_ptr->wiphy);
  80                         dev_put(dev);
  81                 }
  82                 err = -ENODEV;
  83         }
  84
  85         if (bywiphyidx && byifidx) {
  86                 if (bywiphyidx != byifidx)
  87                         return ERR_PTR(-EINVAL);
  88                 else
  89                         return bywiphyidx; /* == byifidx */
  90         }
  91         if (bywiphyidx)
  92                 return bywiphyidx;
  93
  94         if (byifidx)
  95                 return byifidx;
  96
  97         return ERR_PTR(err);
  98 }
  99
 100 struct cfg80211_registered_device *
 101 cfg80211_get_dev_from_info(struct genl_info *info)
 102 {
 103         struct cfg80211_registered_device *drv;
 104
 105         mutex_lock(&cfg80211_drv_mutex);
 106         drv = __cfg80211_drv_from_info(info);
 107
 108         /* if it is not an error we grab the lock on
 109          * it to assure it won't be going away while
 110          * we operate on it */
 111         if (!IS_ERR(drv))
 112                 mutex_lock(&drv->mtx);
 113
 114         mutex_unlock(&cfg80211_drv_mutex);
 115
 116         return drv;
 117 }
 118
 119 struct cfg80211_registered_device *
 120 cfg80211_get_dev_from_ifindex(int ifindex)
 121 {
 122         struct cfg80211_registered_device *drv = ERR_PTR(-ENODEV);
 123         struct net_device *dev;
 124
 125         mutex_lock(&cfg80211_drv_mutex);
 126         dev = dev_get_by_index(&init_net, ifindex);
 127         if (!dev)
 128                 goto out;
 129         if (dev->ieee80211_ptr) {
 130                 drv = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 131                 mutex_lock(&drv->mtx);
 132         } else
 133                 drv = ERR_PTR(-ENODEV);
 134         dev_put(dev);
 135  out:
 136         mutex_unlock(&cfg80211_drv_mutex);
 137         return drv;
 138 }
 139
 140 void cfg80211_put_dev(struct cfg80211_registered_device *drv)
 141 {
 142         BUG_ON(IS_ERR(drv));
 143         mutex_unlock(&drv->mtx);
 144 }
 145
 146 int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
 147                         char *newname)
 148 {
 149         struct cfg80211_registered_device *drv;
 150         int wiphy_idx, taken = -1, result, digits;
 151
 152         mutex_lock(&cfg80211_drv_mutex);
 153
 154         /* prohibit calling the thing phy%d when %d is not its number */
 155         sscanf(newname, PHY_NAME "%d%n", &wiphy_idx, &taken);
 156         if (taken == strlen(newname) && wiphy_idx != rdev->wiphy_idx) {
 157                 /* count number of places needed to print wiphy_idx */
 158                 digits = 1;
 159                 while (wiphy_idx /= 10)
 160                         digits++;
 161                 /*
 162                  * deny the name if it is phy<idx> where <idx> is printed
 163                  * without leading zeroes. taken == strlen(newname) here
 164                  */
 165                 result = -EINVAL;
 166                 if (taken == strlen(PHY_NAME) + digits)
 167                         goto out_unlock;
 168         }
 169
 170
 171         /* Ignore nop renames */
 172         result = 0;
 173         if (strcmp(newname, dev_name(&rdev->wiphy.dev)) == 0)
 174                 goto out_unlock;
 175
 176         /* Ensure another device does not already have this name. */
 177         list_for_each_entry(drv, &cfg80211_drv_list, list) {
 178                 result = -EINVAL;
 179                 if (strcmp(newname, dev_name(&drv->wiphy.dev)) == 0)
 180                         goto out_unlock;
 181         }
 182
 183         /* this will only check for collisions in sysfs
 184          * which is not even always compiled in.
 185          */
 186         result = device_rename(&rdev->wiphy.dev, newname);
 187         if (result)
 188                 goto out_unlock;
 189
 190         if (rdev->wiphy.debugfsdir &&
 191             !debugfs_rename(rdev->wiphy.debugfsdir->d_parent,
 192                             rdev->wiphy.debugfsdir,
 193                             rdev->wiphy.debugfsdir->d_parent,
 194                             newname))
 195                 printk(KERN_ERR "cfg80211: failed to rename debugfs dir to %s!\n",
 196                        newname);
 197
 198         result = 0;
 199 out_unlock:
 200         mutex_unlock(&cfg80211_drv_mutex);
 201         if (result == 0)
 202                 nl80211_notify_dev_rename(rdev);
 203
 204         return result;
 205 }
 206
 207 /* exported functions */
 208
 209 struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
 210 {
 211         static int wiphy_counter;
 212
 213         struct cfg80211_registered_device *drv;
 214         int alloc_size;
 215
 216         WARN_ON(!ops->add_key && ops->del_key);
 217         WARN_ON(ops->add_key && !ops->del_key);
 218
 219         alloc_size = sizeof(*drv) + sizeof_priv;
 220
 221         drv = kzalloc(alloc_size, GFP_KERNEL);
 222         if (!drv)
 223                 return NULL;
 224
 225         drv->ops = ops;
 226
 227         mutex_lock(&cfg80211_drv_mutex);
 228
 229         drv->wiphy_idx = wiphy_counter++;
 230
 231         if (unlikely(!wiphy_idx_valid(drv->wiphy_idx))) {
 232                 wiphy_counter--;
 233                 mutex_unlock(&cfg80211_drv_mutex);
 234                 /* ugh, wrapped! */
 235                 kfree(drv);
 236                 return NULL;
 237         }
 238
 239         mutex_unlock(&cfg80211_drv_mutex);
 240
 241         /* give it a proper name */
 242         dev_set_name(&drv->wiphy.dev, PHY_NAME "%d", drv->wiphy_idx);
 243
 244         mutex_init(&drv->mtx);
 245         mutex_init(&drv->devlist_mtx);
 246         INIT_LIST_HEAD(&drv->netdev_list);
 247         spin_lock_init(&drv->bss_lock);
 248         INIT_LIST_HEAD(&drv->bss_list);
 249
 250         device_initialize(&drv->wiphy.dev);
 251         drv->wiphy.dev.class = &ieee80211_class;
 252         drv->wiphy.dev.platform_data = drv;
 253
 254         return &drv->wiphy;
 255 }
 256 EXPORT_SYMBOL(wiphy_new);
 257
 258 int wiphy_register(struct wiphy *wiphy)
 259 {
 260         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 261         int res;
 262         enum ieee80211_band band;
 263         struct ieee80211_supported_band *sband;
 264         bool have_band = false;
 265         int i;
 266         u16 ifmodes = wiphy->interface_modes;
 267
 268         if (WARN_ON(wiphy->max_scan_ssids < 1))
 269                 return -EINVAL;
 270
 271         /* sanity check ifmodes */
 272         WARN_ON(!ifmodes);
 273         ifmodes &= ((1 << __NL80211_IFTYPE_AFTER_LAST) - 1) & ~1;
 274         if (WARN_ON(ifmodes != wiphy->interface_modes))
 275                 wiphy->interface_modes = ifmodes;
 276
 277         /* sanity check supported bands/channels */
 278         for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
 279                 sband = wiphy->bands[band];
 280                 if (!sband)
 281                         continue;
 282
 283                 sband->band = band;
 284
 285                 if (WARN_ON(!sband->n_channels || !sband->n_bitrates))
 286                         return -EINVAL;
 287
 288                 /*
 289                  * Since we use a u32 for rate bitmaps in
 290                  * ieee80211_get_response_rate, we cannot
 291                  * have more than 32 legacy rates.
 292                  */
 293                 if (WARN_ON(sband->n_bitrates > 32))
 294                         return -EINVAL;
 295
 296                 for (i = 0; i < sband->n_channels; i++) {
 297                         sband->channels[i].orig_flags =
 298                                 sband->channels[i].flags;
 299                         sband->channels[i].orig_mag =
 300                                 sband->channels[i].max_antenna_gain;
 301                         sband->channels[i].orig_mpwr =
 302                                 sband->channels[i].max_power;
 303                         sband->channels[i].band = band;
 304                 }
 305
 306                 have_band = true;
 307         }
 308
 309         if (!have_band) {
 310                 WARN_ON(1);
 311                 return -EINVAL;
 312         }
 313
 314         /* check and set up bitrates */
 315         ieee80211_set_bitrate_flags(wiphy);
 316
 317         mutex_lock(&cfg80211_drv_mutex);
 318
 319         /* set up regulatory info */
 320         wiphy_update_regulatory(wiphy, REGDOM_SET_BY_CORE);
 321
 322         res = device_add(&drv->wiphy.dev);
 323         if (res)
 324                 goto out_unlock;
 325
 326         list_add(&drv->list, &cfg80211_drv_list);
 327
 328         /* add to debugfs */
 329         drv->wiphy.debugfsdir =
 330                 debugfs_create_dir(wiphy_name(&drv->wiphy),
 331                                    ieee80211_debugfs_dir);
 332         if (IS_ERR(drv->wiphy.debugfsdir))
 333                 drv->wiphy.debugfsdir = NULL;
 334
 335         res = 0;
 336 out_unlock:
 337         mutex_unlock(&cfg80211_drv_mutex);
 338         return res;
 339 }
 340 EXPORT_SYMBOL(wiphy_register);
 341
 342 void wiphy_unregister(struct wiphy *wiphy)
 343 {
 344         struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
 345
 346         /* protect the device list */
 347         mutex_lock(&cfg80211_drv_mutex);
 348
 349         BUG_ON(!list_empty(&drv->netdev_list));
 350
 351         /*
 352          * Try to grab drv->mtx. If a command is still in progress,
 353          * hopefully the driver will refuse it since it's tearing
 354          * down the device already. We wait for this command to complete
 355          * before unlinking the item from the list.
 356          * Note: as codified by the BUG_ON above we cannot get here if
 357          * a virtual interface is still associated. Hence, we can only
 358          * get to lock contention here if userspace issues a command
 359          * that identified the hardware by wiphy index.
 360          */
 361         mutex_lock(&drv->mtx);
 362         /* unlock again before freeing */
 363         mutex_unlock(&drv->mtx);
 364
 365         /* If this device got a regulatory hint tell core its
 366          * free to listen now to a new shiny device regulatory hint */
 367         reg_device_remove(wiphy);
 368
 369         list_del(&drv->list);
 370         device_del(&drv->wiphy.dev);
 371         debugfs_remove(drv->wiphy.debugfsdir);
 372
 373         mutex_unlock(&cfg80211_drv_mutex);
 374 }
 375 EXPORT_SYMBOL(wiphy_unregister);
 376
 377 void cfg80211_dev_free(struct cfg80211_registered_device *drv)
 378 {
 379         struct cfg80211_internal_bss *scan, *tmp;
 380         mutex_destroy(&drv->mtx);
 381         mutex_destroy(&drv->devlist_mtx);
 382         list_for_each_entry_safe(scan, tmp, &drv->bss_list, list)
 383                 cfg80211_put_bss(&scan->pub);
 384         kfree(drv);
 385 }
 386
 387 void wiphy_free(struct wiphy *wiphy)
 388 {
 389         put_device(&wiphy->dev);
 390 }
 391 EXPORT_SYMBOL(wiphy_free);
 392
 393 static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
 394                                          unsigned long state,
 395                                          void *ndev)
 396 {
 397         struct net_device *dev = ndev;
 398         struct cfg80211_registered_device *rdev;
 399
 400         if (!dev->ieee80211_ptr)
 401                 return 0;
 402
 403         rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
 404
 405         WARN_ON(dev->ieee80211_ptr->iftype == NL80211_IFTYPE_UNSPECIFIED);
 406
 407         switch (state) {
 408         case NETDEV_REGISTER:
 409                 mutex_lock(&rdev->devlist_mtx);
 410                 list_add(&dev->ieee80211_ptr->list, &rdev->netdev_list);
 411                 if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
 412                                       "phy80211")) {
 413                         printk(KERN_ERR "wireless: failed to add phy80211 "
 414                                 "symlink to netdev!\n");
 415                 }
 416                 dev->ieee80211_ptr->netdev = dev;
 417                 mutex_unlock(&rdev->devlist_mtx);
 418                 break;
 419         case NETDEV_UNREGISTER:
 420                 mutex_lock(&rdev->devlist_mtx);
 421                 if (!list_empty(&dev->ieee80211_ptr->list)) {
 422                         sysfs_remove_link(&dev->dev.kobj, "phy80211");
 423                         list_del_init(&dev->ieee80211_ptr->list);
 424                 }
 425                 mutex_unlock(&rdev->devlist_mtx);
 426                 break;
 427         }
 428
 429         return 0;
 430 }
 431
 432 static struct notifier_block cfg80211_netdev_notifier = {
 433         .notifier_call = cfg80211_netdev_notifier_call,
 434 };
 435
 436 static int cfg80211_init(void)
 437 {
 438         int err;
 439
 440         err = wiphy_sysfs_init();
 441         if (err)
 442                 goto out_fail_sysfs;
 443
 444         err = register_netdevice_notifier(&cfg80211_netdev_notifier);
 445         if (err)
 446                 goto out_fail_notifier;
 447
 448         err = nl80211_init();
 449         if (err)
 450                 goto out_fail_nl80211;
 451
 452         ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);
 453
 454         err = regulatory_init();
 455         if (err)
 456                 goto out_fail_reg;
 457
 458         return 0;
 459
 460 out_fail_reg:
 461         debugfs_remove(ieee80211_debugfs_dir);
 462 out_fail_nl80211:
 463         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 464 out_fail_notifier:
 465         wiphy_sysfs_exit();
 466 out_fail_sysfs:
 467         return err;
 468 }
 469
 470 subsys_initcall(cfg80211_init);
 471
 472 static void cfg80211_exit(void)
 473 {
 474         debugfs_remove(ieee80211_debugfs_dir);
 475         nl80211_exit();
 476         unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 477         wiphy_sysfs_exit();
 478         regulatory_exit();
 479 }
 480 module_exit(cfg80211_exit);