ClabureDB: Classified Bug-Reports Database

  /*
   * This is the linux wireless configuration interface.
   *
   * Copyright 2006-2008                Johannes Berg <johannes@sipsolutions.net>
   */
  
  #include <linux/if.h>
  #include <linux/module.h>
  #include <linux/err.h>
 #include <linux/mutex.h>
 #include <linux/list.h>
 #include <linux/nl80211.h>
 #include <linux/debugfs.h>
 #include <linux/notifier.h>
 #include <linux/device.h>
 #include <net/genetlink.h>
 #include <net/cfg80211.h>
 #include <net/wireless.h>
 #include "nl80211.h"
 #include "core.h"
 #include "sysfs.h"
 #include "reg.h"
 
 /* name for sysfs, %d is appended */
 #define PHY_NAME "phy"
 
 MODULE_AUTHOR("Johannes Berg");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("wireless configuration support");
 
 /* RCU might be appropriate here since we usually
  * only read the list, and that can happen quite
  * often because we need to do it for each command */
 LIST_HEAD(cfg80211_drv_list);
 DEFINE_MUTEX(cfg80211_drv_mutex);
 
 /* for debugfs */
 static struct dentry *ieee80211_debugfs_dir;
 
 /* requires cfg80211_drv_mutex to be held! */
 static struct cfg80211_registered_device *cfg80211_drv_by_wiphy(int wiphy)
 {
         struct cfg80211_registered_device *result = NULL, *drv;
 
         list_for_each_entry(drv, &cfg80211_drv_list, list) {
                 if (drv->idx == wiphy) {
                         result = drv;
                         break;
                 }
         }
 
         return result;
 }
 
 /* requires cfg80211_drv_mutex to be held! */
 static struct cfg80211_registered_device *
 __cfg80211_drv_from_info(struct genl_info *info)
 {
         int ifindex;
         struct cfg80211_registered_device *bywiphy = NULL, *byifidx = NULL;
         struct net_device *dev;
         int err = -EINVAL;
 
         if (info->attrs[NL80211_ATTR_WIPHY]) {
                 bywiphy = cfg80211_drv_by_wiphy(
                                 nla_get_u32(info->attrs[NL80211_ATTR_WIPHY]));
                 err = -ENODEV;
         }
 
         if (info->attrs[NL80211_ATTR_IFINDEX]) {
                 ifindex = nla_get_u32(info->attrs[NL80211_ATTR_IFINDEX]);
                 dev = dev_get_by_index(&init_net, ifindex);
                 if (dev) {
                         if (dev->ieee80211_ptr)
                                 byifidx =
                                         wiphy_to_dev(dev->ieee80211_ptr->wiphy);
                         dev_put(dev);
                 }
                 err = -ENODEV;
         }
 
         if (bywiphy && byifidx) {
                 if (bywiphy != byifidx)
                         return ERR_PTR(-EINVAL);
                 else
                         return bywiphy; /* == byifidx */
         }
         if (bywiphy)
                 return bywiphy;
 
         if (byifidx)
                 return byifidx;
 
         return ERR_PTR(err);
 }
 
 struct cfg80211_registered_device *
 cfg80211_get_dev_from_info(struct genl_info *info)
 {
        struct cfg80211_registered_device *drv;

        mutex_lock(&cfg80211_drv_mutex);
        drv = __cfg80211_drv_from_info(info);

        /* if it is not an error we grab the lock on
         * it to assure it won't be going away while
         * we operate on it */
        if (!IS_ERR(drv))
                mutex_lock(&drv->mtx);

        mutex_unlock(&cfg80211_drv_mutex);

        return drv;
}

struct cfg80211_registered_device *
cfg80211_get_dev_from_ifindex(int ifindex)
{
        struct cfg80211_registered_device *drv = ERR_PTR(-ENODEV);
        struct net_device *dev;

        mutex_lock(&cfg80211_drv_mutex);
        dev = dev_get_by_index(&init_net, ifindex);
        if (!dev)
                goto out;
        if (dev->ieee80211_ptr) {
                drv = wiphy_to_dev(dev->ieee80211_ptr->wiphy);
                mutex_lock(&drv->mtx);
        } else
                drv = ERR_PTR(-ENODEV);
        dev_put(dev);
 out:
        mutex_unlock(&cfg80211_drv_mutex);
        return drv;
}

void cfg80211_put_dev(struct cfg80211_registered_device *drv)
{
        BUG_ON(IS_ERR(drv));
        mutex_unlock(&drv->mtx);
}

int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
                        char *newname)
{
        struct cfg80211_registered_device *drv;
        int idx, taken = -1, result, digits;

        mutex_lock(&cfg80211_drv_mutex);

        /* prohibit calling the thing phy%d when %d is not its number */
        sscanf(newname, PHY_NAME "%d%n", &idx, &taken);
        if (taken == strlen(newname) && idx != rdev->idx) {
                /* count number of places needed to print idx */
                digits = 1;
                while (idx /= 10)
                        digits++;
                /*
                 * deny the name if it is phy<idx> where <idx> is printed
                 * without leading zeroes. taken == strlen(newname) here
                 */
                result = -EINVAL;
                if (taken == strlen(PHY_NAME) + digits)
                        goto out_unlock;
        }


        /* Ignore nop renames */
        result = 0;
        if (strcmp(newname, dev_name(&rdev->wiphy.dev)) == 0)
                goto out_unlock;

        /* Ensure another device does not already have this name. */
        list_for_each_entry(drv, &cfg80211_drv_list, list) {
                result = -EINVAL;
                if (strcmp(newname, dev_name(&drv->wiphy.dev)) == 0)
                        goto out_unlock;
        }

        /* this will only check for collisions in sysfs
         * which is not even always compiled in.
         */
        result = device_rename(&rdev->wiphy.dev, newname);
        if (result)
                goto out_unlock;

        if (rdev->wiphy.debugfsdir &&
            !debugfs_rename(rdev->wiphy.debugfsdir->d_parent,
                            rdev->wiphy.debugfsdir,
                            rdev->wiphy.debugfsdir->d_parent,
                            newname))
                printk(KERN_ERR "cfg80211: failed to rename debugfs dir to %s!\n",
                       newname);

        result = 0;
out_unlock:
        mutex_unlock(&cfg80211_drv_mutex);
        if (result == 0)
                nl80211_notify_dev_rename(rdev);

        return result;
}

/* exported functions */

struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
{
        static int wiphy_counter;

        struct cfg80211_registered_device *drv;
        int alloc_size;

        WARN_ON(!ops->add_key && ops->del_key);
        WARN_ON(ops->add_key && !ops->del_key);

        alloc_size = sizeof(*drv) + sizeof_priv;

        drv = kzalloc(alloc_size, GFP_KERNEL);
        if (!drv)
                return NULL;

        drv->ops = ops;

        mutex_lock(&cfg80211_drv_mutex);

        drv->idx = wiphy_counter++;

        if (unlikely(drv->idx < 0)) {
                wiphy_counter--;
                mutex_unlock(&cfg80211_drv_mutex);
                /* ugh, wrapped! */
                kfree(drv);
                return NULL;
        }

        mutex_unlock(&cfg80211_drv_mutex);

        /* give it a proper name */
        snprintf(drv->wiphy.dev.bus_id, BUS_ID_SIZE,
                 PHY_NAME "%d", drv->idx);

        mutex_init(&drv->mtx);
        mutex_init(&drv->devlist_mtx);
        INIT_LIST_HEAD(&drv->netdev_list);

        device_initialize(&drv->wiphy.dev);
        drv->wiphy.dev.class = &ieee80211_class;
        drv->wiphy.dev.platform_data = drv;

        return &drv->wiphy;
}
EXPORT_SYMBOL(wiphy_new);

int wiphy_register(struct wiphy *wiphy)
{
        struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);
        int res;
        enum ieee80211_band band;
        struct ieee80211_supported_band *sband;
        bool have_band = false;
        int i;
        u16 ifmodes = wiphy->interface_modes;

        /* sanity check ifmodes */
        WARN_ON(!ifmodes);
        ifmodes &= ((1 << __NL80211_IFTYPE_AFTER_LAST) - 1) & ~1;
        if (WARN_ON(ifmodes != wiphy->interface_modes))
                wiphy->interface_modes = ifmodes;

        /* sanity check supported bands/channels */
        for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                sband = wiphy->bands[band];
                if (!sband)
                        continue;

                sband->band = band;

                if (!sband->n_channels || !sband->n_bitrates) {
                        WARN_ON(1);
                        return -EINVAL;
                }

                for (i = 0; i < sband->n_channels; i++) {
                        sband->channels[i].orig_flags =
                                sband->channels[i].flags;
                        sband->channels[i].orig_mag =
                                sband->channels[i].max_antenna_gain;
                        sband->channels[i].orig_mpwr =
                                sband->channels[i].max_power;
                        sband->channels[i].band = band;
                }

                have_band = true;
        }

        if (!have_band) {
                WARN_ON(1);
                return -EINVAL;
        }

        /* check and set up bitrates */
        ieee80211_set_bitrate_flags(wiphy);

        /* set up regulatory info */
        mutex_lock(&cfg80211_reg_mutex);
        wiphy_update_regulatory(wiphy, REGDOM_SET_BY_CORE);
        mutex_unlock(&cfg80211_reg_mutex);

        mutex_lock(&cfg80211_drv_mutex);

        res = device_add(&drv->wiphy.dev);
        if (res)
                goto out_unlock;

        list_add(&drv->list, &cfg80211_drv_list);

        /* add to debugfs */
        drv->wiphy.debugfsdir =
                debugfs_create_dir(wiphy_name(&drv->wiphy),
                                   ieee80211_debugfs_dir);
        if (IS_ERR(drv->wiphy.debugfsdir))
                drv->wiphy.debugfsdir = NULL;

        res = 0;
out_unlock:
        mutex_unlock(&cfg80211_drv_mutex);
        return res;
}
EXPORT_SYMBOL(wiphy_register);

void wiphy_unregister(struct wiphy *wiphy)
{
        struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);

        /* protect the device list */
        mutex_lock(&cfg80211_drv_mutex);

        BUG_ON(!list_empty(&drv->netdev_list));

        /*
         * Try to grab drv->mtx. If a command is still in progress,
         * hopefully the driver will refuse it since it's tearing
         * down the device already. We wait for this command to complete
         * before unlinking the item from the list.
         * Note: as codified by the BUG_ON above we cannot get here if
         * a virtual interface is still associated. Hence, we can only
         * get to lock contention here if userspace issues a command
         * that identified the hardware by wiphy index.
         */
        mutex_lock(&drv->mtx);
        /* unlock again before freeing */
        mutex_unlock(&drv->mtx);

        list_del(&drv->list);
        device_del(&drv->wiphy.dev);
        debugfs_remove(drv->wiphy.debugfsdir);

        mutex_unlock(&cfg80211_drv_mutex);
}
EXPORT_SYMBOL(wiphy_unregister);

void cfg80211_dev_free(struct cfg80211_registered_device *drv)
{
        mutex_destroy(&drv->mtx);
        mutex_destroy(&drv->devlist_mtx);
        kfree(drv);
}

void wiphy_free(struct wiphy *wiphy)
{
        put_device(&wiphy->dev);
}
EXPORT_SYMBOL(wiphy_free);

static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
                                         unsigned long state,
                                         void *ndev)
{
        struct net_device *dev = ndev;
        struct cfg80211_registered_device *rdev;

        if (!dev->ieee80211_ptr)
                return 0;

        rdev = wiphy_to_dev(dev->ieee80211_ptr->wiphy);

        WARN_ON(dev->ieee80211_ptr->iftype == NL80211_IFTYPE_UNSPECIFIED);

        switch (state) {
        case NETDEV_REGISTER:
                mutex_lock(&rdev->devlist_mtx);
                list_add(&dev->ieee80211_ptr->list, &rdev->netdev_list);
                if (sysfs_create_link(&dev->dev.kobj, &rdev->wiphy.dev.kobj,
                                      "phy80211")) {
                        printk(KERN_ERR "wireless: failed to add phy80211 "
                                "symlink to netdev!\n");
                }
                dev->ieee80211_ptr->netdev = dev;
                mutex_unlock(&rdev->devlist_mtx);
                break;
        case NETDEV_UNREGISTER:
                mutex_lock(&rdev->devlist_mtx);
                if (!list_empty(&dev->ieee80211_ptr->list)) {
                        sysfs_remove_link(&dev->dev.kobj, "phy80211");
                        list_del_init(&dev->ieee80211_ptr->list);
                }
                mutex_unlock(&rdev->devlist_mtx);
                break;
        }

        return 0;
}

static struct notifier_block cfg80211_netdev_notifier = {
        .notifier_call = cfg80211_netdev_notifier_call,
};

static int cfg80211_init(void)
{
        int err;

        err = wiphy_sysfs_init();
        if (err)
                goto out_fail_sysfs;

        err = register_netdevice_notifier(&cfg80211_netdev_notifier);
        if (err)
                goto out_fail_notifier;

        err = nl80211_init();
        if (err)
                goto out_fail_nl80211;

        ieee80211_debugfs_dir = debugfs_create_dir("ieee80211", NULL);

        err = regulatory_init();
        if (err)
                goto out_fail_reg;

        return 0;

out_fail_reg:
        debugfs_remove(ieee80211_debugfs_dir);
out_fail_nl80211:
        unregister_netdevice_notifier(&cfg80211_netdev_notifier);
out_fail_notifier:
        wiphy_sysfs_exit();
out_fail_sysfs:
        return err;
}

subsys_initcall(cfg80211_init);

static void cfg80211_exit(void)
{
        debugfs_remove(ieee80211_debugfs_dir);
        nl80211_exit();
        unregister_netdevice_notifier(&cfg80211_netdev_notifier);
        wiphy_sysfs_exit();
        regulatory_exit();
}
module_exit(cfg80211_exit);