linux/net/wireless/core.c
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   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
  26MODULE_AUTHOR("Johannes Berg");
  27MODULE_LICENSE("GPL");
  28MODULE_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 */
  33LIST_HEAD(cfg80211_drv_list);
  34DEFINE_MUTEX(cfg80211_drv_mutex);
  35
  36/* for debugfs */
  37static struct dentry *ieee80211_debugfs_dir;
  38
  39/* requires cfg80211_drv_mutex to be held! */
  40static 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! */
  55static 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
  96struct cfg80211_registered_device *
  97cfg80211_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
 115struct cfg80211_registered_device *
 116cfg80211_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
 136void cfg80211_put_dev(struct cfg80211_registered_device *drv)
 137{
 138        BUG_ON(IS_ERR(drv));
 139        mutex_unlock(&drv->mtx);
 140}
 141
 142int 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;
 195out_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
 205struct 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}
 250EXPORT_SYMBOL(wiphy_new);
 251
 252int 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;
 321out_unlock:
 322        mutex_unlock(&cfg80211_drv_mutex);
 323        return res;
 324}
 325EXPORT_SYMBOL(wiphy_register);
 326
 327void 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}
 360EXPORT_SYMBOL(wiphy_unregister);
 361
 362void 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
 369void wiphy_free(struct wiphy *wiphy)
 370{
 371        put_device(&wiphy->dev);
 372}
 373EXPORT_SYMBOL(wiphy_free);
 374
 375static 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
 414static struct notifier_block cfg80211_netdev_notifier = {
 415        .notifier_call = cfg80211_netdev_notifier_call,
 416};
 417
 418static 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
 442out_fail_reg:
 443        debugfs_remove(ieee80211_debugfs_dir);
 444out_fail_nl80211:
 445        unregister_netdevice_notifier(&cfg80211_netdev_notifier);
 446out_fail_notifier:
 447        wiphy_sysfs_exit();
 448out_fail_sysfs:
 449        return err;
 450}
 451
 452subsys_initcall(cfg80211_init);
 453
 454static 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}
 462module_exit(cfg80211_exit);
 463