cfg80211: fix locking

[linux-block.git] / net / wireless / core.c

/*
 * This is the linux wireless configuration interface.
 *
 * Copyright 2006-2009		Johannes Berg <johannes@sipsolutions.net>
 */

#include <linux/if.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/nl80211.h>
#include <linux/debugfs.h>
#include <linux/notifier.h>
#include <linux/device.h>
#include <linux/rtnetlink.h>
#include <net/genetlink.h>
#include <net/cfg80211.h>
#include "nl80211.h"
#include "core.h"
#include "sysfs.h"
#include "debugfs.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);

/*
 * This is used to protect the cfg80211_drv_list, cfg80211_regdomain,
 * country_ie_regdomain, the reg_beacon_list and the the last regulatory
 * request receipt (last_request).
 */
DEFINE_MUTEX(cfg80211_mutex);

/* for debugfs */
static struct dentry *ieee80211_debugfs_dir;

/* requires cfg80211_mutex to be held! */
struct cfg80211_registered_device *cfg80211_drv_by_wiphy_idx(int wiphy_idx)
{
	struct cfg80211_registered_device *result = NULL, *drv;

	if (!wiphy_idx_valid(wiphy_idx))
		return NULL;

	assert_cfg80211_lock();

	list_for_each_entry(drv, &cfg80211_drv_list, list) {
		if (drv->wiphy_idx == wiphy_idx) {
			result = drv;
			break;
		}
	}

	return result;
}

int get_wiphy_idx(struct wiphy *wiphy)
{
	struct cfg80211_registered_device *drv;
	if (!wiphy)
		return WIPHY_IDX_STALE;
	drv = wiphy_to_dev(wiphy);
	return drv->wiphy_idx;
}

/* requires cfg80211_drv_mutex to be held! */
struct wiphy *wiphy_idx_to_wiphy(int wiphy_idx)
{
	struct cfg80211_registered_device *drv;

	if (!wiphy_idx_valid(wiphy_idx))
		return NULL;

	assert_cfg80211_lock();

	drv = cfg80211_drv_by_wiphy_idx(wiphy_idx);
	if (!drv)
		return NULL;
	return &drv->wiphy;
}

/* requires cfg80211_mutex to be held! */
struct cfg80211_registered_device *
__cfg80211_drv_from_info(struct genl_info *info)
{
	int ifindex;
	struct cfg80211_registered_device *bywiphyidx = NULL, *byifidx = NULL;
	struct net_device *dev;
	int err = -EINVAL;

	assert_cfg80211_lock();

	if (info->attrs[NL80211_ATTR_WIPHY]) {
		bywiphyidx = cfg80211_drv_by_wiphy_idx(
				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 (bywiphyidx && byifidx) {
		if (bywiphyidx != byifidx)
			return ERR_PTR(-EINVAL);
		else
			return bywiphyidx; /* == byifidx */
	}
	if (bywiphyidx)
		return bywiphyidx;

	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_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_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_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_mutex);
	return drv;
}

/* requires cfg80211_mutex to be held */
int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
			char *newname)
{
	struct cfg80211_registered_device *drv;
	int wiphy_idx, taken = -1, result, digits;

	assert_cfg80211_lock();

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


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

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

	result = device_rename(&rdev->wiphy.dev, newname);
	if (result)
		return result;

	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);

	nl80211_notify_dev_rename(rdev);

	return 0;
}

static void cfg80211_rfkill_poll(struct rfkill *rfkill, void *data)
{
	struct cfg80211_registered_device *drv = data;

	drv->ops->rfkill_poll(&drv->wiphy);
}

static int cfg80211_rfkill_set_block(void *data, bool blocked)
{
	struct cfg80211_registered_device *drv = data;
	struct wireless_dev *wdev;

	if (!blocked)
		return 0;

	rtnl_lock();
	mutex_lock(&drv->devlist_mtx);

	list_for_each_entry(wdev, &drv->netdev_list, list)
		dev_close(wdev->netdev);

	mutex_unlock(&drv->devlist_mtx);
	rtnl_unlock();

	return 0;
}

static void cfg80211_rfkill_sync_work(struct work_struct *work)
{
	struct cfg80211_registered_device *drv;

	drv = container_of(work, struct cfg80211_registered_device, rfkill_sync);
	cfg80211_rfkill_set_block(drv, rfkill_blocked(drv->rfkill));
}

static void cfg80211_process_events(struct wireless_dev *wdev)
{
	struct cfg80211_event *ev;
	unsigned long flags;

	spin_lock_irqsave(&wdev->event_lock, flags);
	while (!list_empty(&wdev->event_list)) {
		ev = list_first_entry(&wdev->event_list,
				      struct cfg80211_event, list);
		list_del(&ev->list);
		spin_unlock_irqrestore(&wdev->event_lock, flags);

		wdev_lock(wdev);
		switch (ev->type) {
		case EVENT_CONNECT_RESULT:
			__cfg80211_connect_result(
				wdev->netdev, ev->cr.bssid,
				ev->cr.req_ie, ev->cr.req_ie_len,
				ev->cr.resp_ie, ev->cr.resp_ie_len,
				ev->cr.status,
				ev->cr.status == WLAN_STATUS_SUCCESS);
			break;
		case EVENT_ROAMED:
			__cfg80211_roamed(wdev, ev->rm.bssid,
					  ev->rm.req_ie, ev->rm.req_ie_len,
					  ev->rm.resp_ie, ev->rm.resp_ie_len);
			break;
		case EVENT_DISCONNECTED:
			__cfg80211_disconnected(wdev->netdev,
						ev->dc.ie, ev->dc.ie_len,
						ev->dc.reason, true);
			break;
		case EVENT_IBSS_JOINED:
			__cfg80211_ibss_joined(wdev->netdev, ev->ij.bssid);
			break;
		}
		wdev_unlock(wdev);

		kfree(ev);

		spin_lock_irqsave(&wdev->event_lock, flags);
	}
	spin_unlock_irqrestore(&wdev->event_lock, flags);
}

static void cfg80211_event_work(struct work_struct *work)
{
	struct cfg80211_registered_device *rdev;
	struct wireless_dev *wdev;

	rdev = container_of(work, struct cfg80211_registered_device,
			    event_work);

	rtnl_lock();
	cfg80211_lock_rdev(rdev);
	mutex_lock(&rdev->devlist_mtx);

	list_for_each_entry(wdev, &rdev->netdev_list, list)
		cfg80211_process_events(wdev);

	mutex_unlock(&rdev->devlist_mtx);
	cfg80211_unlock_rdev(rdev);
	rtnl_unlock();
}

/* exported functions */

struct wiphy *wiphy_new(const 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_mutex);

	drv->wiphy_idx = wiphy_counter++;

	if (unlikely(!wiphy_idx_valid(drv->wiphy_idx))) {
		wiphy_counter--;
		mutex_unlock(&cfg80211_mutex);
		/* ugh, wrapped! */
		kfree(drv);
		return NULL;
	}

	mutex_unlock(&cfg80211_mutex);

	/* give it a proper name */
	dev_set_name(&drv->wiphy.dev, PHY_NAME "%d", drv->wiphy_idx);

	mutex_init(&drv->mtx);
	mutex_init(&drv->devlist_mtx);
	INIT_LIST_HEAD(&drv->netdev_list);
	spin_lock_init(&drv->bss_lock);
	INIT_LIST_HEAD(&drv->bss_list);
	INIT_WORK(&drv->scan_done_wk, __cfg80211_scan_done);

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

	drv->rfkill_ops.set_block = cfg80211_rfkill_set_block;
	drv->rfkill = rfkill_alloc(dev_name(&drv->wiphy.dev),
				   &drv->wiphy.dev, RFKILL_TYPE_WLAN,
				   &drv->rfkill_ops, drv);

	if (!drv->rfkill) {
		kfree(drv);
		return NULL;
	}

	INIT_WORK(&drv->rfkill_sync, cfg80211_rfkill_sync_work);
	INIT_WORK(&drv->conn_work, cfg80211_conn_work);
	INIT_WORK(&drv->event_work, cfg80211_event_work);

	/*
	 * Initialize wiphy parameters to IEEE 802.11 MIB default values.
	 * Fragmentation and RTS threshold are disabled by default with the
	 * special -1 value.
	 */
	drv->wiphy.retry_short = 7;
	drv->wiphy.retry_long = 4;
	drv->wiphy.frag_threshold = (u32) -1;
	drv->wiphy.rts_threshold = (u32) -1;

	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 (WARN_ON(!sband->n_channels || !sband->n_bitrates))
			return -EINVAL;

		/*
		 * Since we use a u32 for rate bitmaps in
		 * ieee80211_get_response_rate, we cannot
		 * have more than 32 legacy rates.
		 */
		if (WARN_ON(sband->n_bitrates > 32))
			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);

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

	res = rfkill_register(drv->rfkill);
	if (res)
		goto out_rm_dev;

	mutex_lock(&cfg80211_mutex);

	/* set up regulatory info */
	wiphy_update_regulatory(wiphy, NL80211_REGDOM_SET_BY_CORE);

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

	mutex_unlock(&cfg80211_mutex);

	/* 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;

	if (wiphy->custom_regulatory) {
		struct regulatory_request request;

		request.wiphy_idx = get_wiphy_idx(wiphy);
		request.initiator = NL80211_REGDOM_SET_BY_DRIVER;
		request.alpha2[0] = '9';
		request.alpha2[1] = '9';

		nl80211_send_reg_change_event(&request);
	}

	cfg80211_debugfs_drv_add(drv);

	return 0;

 out_rm_dev:
	device_del(&drv->wiphy.dev);
	return res;
}
EXPORT_SYMBOL(wiphy_register);

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

	if (!drv->ops->rfkill_poll)
		return;
	drv->rfkill_ops.poll = cfg80211_rfkill_poll;
	rfkill_resume_polling(drv->rfkill);
}
EXPORT_SYMBOL(wiphy_rfkill_start_polling);

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

	rfkill_pause_polling(drv->rfkill);
}
EXPORT_SYMBOL(wiphy_rfkill_stop_polling);

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

	rfkill_unregister(drv->rfkill);

	/* protect the device list */
	mutex_lock(&cfg80211_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);

	cancel_work_sync(&drv->conn_work);
	cancel_work_sync(&drv->scan_done_wk);
	kfree(drv->scan_req);
	flush_work(&drv->event_work);

	cfg80211_debugfs_drv_del(drv);

	/* If this device got a regulatory hint tell core its
	 * free to listen now to a new shiny device regulatory hint */
	reg_device_remove(wiphy);

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

	mutex_unlock(&cfg80211_mutex);
}
EXPORT_SYMBOL(wiphy_unregister);

void cfg80211_dev_free(struct cfg80211_registered_device *drv)
{
	struct cfg80211_internal_bss *scan, *tmp;
	rfkill_destroy(drv->rfkill);
	mutex_destroy(&drv->mtx);
	mutex_destroy(&drv->devlist_mtx);
	list_for_each_entry_safe(scan, tmp, &drv->bss_list, list)
		cfg80211_put_bss(&scan->pub);
	kfree(drv);
}

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

void wiphy_rfkill_set_hw_state(struct wiphy *wiphy, bool blocked)
{
	struct cfg80211_registered_device *drv = wiphy_to_dev(wiphy);

	if (rfkill_set_hw_state(drv->rfkill, blocked))
		schedule_work(&drv->rfkill_sync);
}
EXPORT_SYMBOL(wiphy_rfkill_set_hw_state);

static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
					 unsigned long state,
					 void *ndev)
{
	struct net_device *dev = ndev;
	struct wireless_dev *wdev = dev->ieee80211_ptr;
	struct cfg80211_registered_device *rdev;

	if (!wdev)
		return NOTIFY_DONE;

	rdev = wiphy_to_dev(wdev->wiphy);

	WARN_ON(wdev->iftype == NL80211_IFTYPE_UNSPECIFIED);

	switch (state) {
	case NETDEV_REGISTER:
		mutex_init(&wdev->mtx);
		INIT_LIST_HEAD(&wdev->event_list);
		spin_lock_init(&wdev->event_lock);
		mutex_lock(&rdev->devlist_mtx);
		list_add(&wdev->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");
		}
		wdev->netdev = dev;
		wdev->sme_state = CFG80211_SME_IDLE;
		mutex_unlock(&rdev->devlist_mtx);
#ifdef CONFIG_WIRELESS_EXT
		wdev->wext.default_key = -1;
		wdev->wext.default_mgmt_key = -1;
		wdev->wext.connect.auth_type = NL80211_AUTHTYPE_AUTOMATIC;
		wdev->wext.ps = CONFIG_CFG80211_DEFAULT_PS_VALUE;
		wdev->wext.ps_timeout = 500;
		if (rdev->ops->set_power_mgmt)
			if (rdev->ops->set_power_mgmt(wdev->wiphy, dev,
						      wdev->wext.ps,
						      wdev->wext.ps_timeout)) {
				/* assume this means it's off */
				wdev->wext.ps = false;
			}
#endif
		break;
	case NETDEV_GOING_DOWN:
		switch (wdev->iftype) {
		case NL80211_IFTYPE_ADHOC:
			cfg80211_leave_ibss(rdev, dev, true);
			break;
		case NL80211_IFTYPE_STATION:
			wdev_lock(wdev);
#ifdef CONFIG_WIRELESS_EXT
			kfree(wdev->wext.ie);
			wdev->wext.ie = NULL;
			wdev->wext.ie_len = 0;
			wdev->wext.connect.auth_type = NL80211_AUTHTYPE_AUTOMATIC;
#endif
			__cfg80211_disconnect(rdev, dev,
					      WLAN_REASON_DEAUTH_LEAVING, true);
			cfg80211_mlme_down(rdev, dev);
			wdev_unlock(wdev);
			break;
		default:
			break;
		}
		break;
	case NETDEV_UP:
#ifdef CONFIG_WIRELESS_EXT
		cfg80211_lock_rdev(rdev);
		wdev_lock(wdev);
		switch (wdev->iftype) {
		case NL80211_IFTYPE_ADHOC:
			if (wdev->wext.ibss.ssid_len)
				__cfg80211_join_ibss(rdev, dev,
						     &wdev->wext.ibss);
			break;
		case NL80211_IFTYPE_STATION:
			if (wdev->wext.connect.ssid_len)
				__cfg80211_connect(rdev, dev,
						   &wdev->wext.connect);
			break;
		default:
			break;
		}
		wdev_unlock(wdev);
		cfg80211_unlock_rdev(rdev);
#endif
		break;
	case NETDEV_UNREGISTER:
		mutex_lock(&rdev->devlist_mtx);
		if (!list_empty(&wdev->list)) {
			sysfs_remove_link(&dev->dev.kobj, "phy80211");
			list_del_init(&wdev->list);
		}
		mutex_unlock(&rdev->devlist_mtx);
		mutex_destroy(&wdev->mtx);
		break;
	case NETDEV_PRE_UP:
		if (rfkill_blocked(rdev->rfkill))
			return notifier_from_errno(-ERFKILL);
		break;
	}

	return NOTIFY_DONE;
}

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);