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/*
* 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 (channel_type != NL80211_CHAN_HT20 &&
(!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT))
return NULL;
}
return chan;
}
static bool can_beacon_sec_chan(struct wiphy *wiphy,
struct ieee80211_channel *chan,
enum nl80211_channel_type channel_type)
{
struct ieee80211_channel *sec_chan;
int diff;
switch (channel_type) {
case NL80211_CHAN_HT40PLUS:
diff = 20;
case NL80211_CHAN_HT40MINUS:
diff = -20;
default:
return false;
}
sec_chan = ieee80211_get_channel(wiphy, chan->center_freq + diff);
if (!sec_chan)
return false;
/* we'll need a DFS capability later */
if (sec_chan->flags & (IEEE80211_CHAN_DISABLED |
IEEE80211_CHAN_PASSIVE_SCAN |
IEEE80211_CHAN_NO_IBSS |
IEEE80211_CHAN_RADAR))
return false;
return true;
}
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;
/* Both channels should be able to initiate communication */
if (wdev && (wdev->iftype == NL80211_IFTYPE_ADHOC ||
wdev->iftype == NL80211_IFTYPE_AP ||
wdev->iftype == NL80211_IFTYPE_AP_VLAN ||
wdev->iftype == NL80211_IFTYPE_MESH_POINT)) {
switch (channel_type) {
case NL80211_CHAN_HT40PLUS:
case NL80211_CHAN_HT40MINUS:
if (!can_beacon_sec_chan(&rdev->wiphy, chan,
channel_type)) {
printk(KERN_DEBUG
"cfg80211: Secondary channel not "
"allowed to initiate communication\n");
return -EINVAL;
}
break;
default:
break;
}
}
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;
}
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