net/wireless/chan.c

/*
 * This file contains helper code to handle channel
 * settings and keeping track of what is possible at
 * any point in time.
 *
 * Copyright 2009	Johannes Berg <johannes@sipsolutions.net>
 */

#include <net/cfg80211.h>
#include "core.h"

struct ieee80211_channel *
rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
		  int freq, enum nl80211_channel_type channel_type)
{
	struct ieee80211_channel *chan;
	struct ieee80211_sta_ht_cap *ht_cap;

	chan = ieee80211_get_channel(&rdev->wiphy, freq);

	/* Primary channel not allowed */
	if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
		return NULL;

	if (channel_type == NL80211_CHAN_HT40MINUS &&
	    chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
		return NULL;
	else if (channel_type == NL80211_CHAN_HT40PLUS &&
		 chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
		return NULL;

	ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;

	if (channel_type != NL80211_CHAN_NO_HT) {
		if (!ht_cap->ht_supported)
			return NULL;

		if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)
			return NULL;
	}

	return chan;
}

int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
		      struct wireless_dev *wdev, int freq,
		      enum nl80211_channel_type channel_type)
{
	struct ieee80211_channel *chan;
	int result;

	if (wdev && wdev->iftype == NL80211_IFTYPE_MONITOR)
		wdev = NULL;

	if (wdev) {
		ASSERT_WDEV_LOCK(wdev);

		if (!netif_running(wdev->netdev))
			return -ENETDOWN;
	}

	if (!rdev->ops->set_channel)
		return -EOPNOTSUPP;

	chan = rdev_freq_to_chan(rdev, freq, channel_type);
	if (!chan)
		return -EINVAL;

	result = rdev->ops->set_channel(&rdev->wiphy,
					wdev ? wdev->netdev : NULL,
					chan, channel_type);
	if (result)
		return result;

	if (wdev)
		wdev->channel = chan;

	return 0;
}