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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/net/mac80211/chan.c
15109 views
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/*

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 * mac80211 - channel management

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 */

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#include <linux/nl80211.h>

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#include "ieee80211_i.h"

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static enum ieee80211_chan_mode

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__ieee80211_get_channel_mode(struct ieee80211_local *local,

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			     struct ieee80211_sub_if_data *ignore)

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{

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	struct ieee80211_sub_if_data *sdata;

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	lockdep_assert_held(&local->iflist_mtx);

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	list_for_each_entry(sdata, &local->interfaces, list) {

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		if (sdata == ignore)

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			continue;

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		if (!ieee80211_sdata_running(sdata))

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			continue;

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		if (sdata->vif.type == NL80211_IFTYPE_MONITOR)

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			continue;

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		if (sdata->vif.type == NL80211_IFTYPE_STATION &&

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		    !sdata->u.mgd.associated)

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			continue;

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		if (sdata->vif.type == NL80211_IFTYPE_ADHOC) {

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			if (!sdata->u.ibss.ssid_len)

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				continue;

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			if (!sdata->u.ibss.fixed_channel)

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				return CHAN_MODE_HOPPING;

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		}

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		if (sdata->vif.type == NL80211_IFTYPE_AP &&

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		    !sdata->u.ap.beacon)

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			continue;

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		return CHAN_MODE_FIXED;

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	}

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	return CHAN_MODE_UNDEFINED;

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}

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enum ieee80211_chan_mode

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ieee80211_get_channel_mode(struct ieee80211_local *local,

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			   struct ieee80211_sub_if_data *ignore)

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{

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	enum ieee80211_chan_mode mode;

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	mutex_lock(&local->iflist_mtx);

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	mode = __ieee80211_get_channel_mode(local, ignore);

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	mutex_unlock(&local->iflist_mtx);

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	return mode;

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}

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bool ieee80211_set_channel_type(struct ieee80211_local *local,

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				struct ieee80211_sub_if_data *sdata,

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				enum nl80211_channel_type chantype)

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{

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	struct ieee80211_sub_if_data *tmp;

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	enum nl80211_channel_type superchan = NL80211_CHAN_NO_HT;

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	bool result;

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	mutex_lock(&local->iflist_mtx);

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	list_for_each_entry(tmp, &local->interfaces, list) {

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		if (tmp == sdata)

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			continue;

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		if (!ieee80211_sdata_running(tmp))

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			continue;

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		switch (tmp->vif.bss_conf.channel_type) {

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		case NL80211_CHAN_NO_HT:

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		case NL80211_CHAN_HT20:

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			if (superchan > tmp->vif.bss_conf.channel_type)

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				break;

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			superchan = tmp->vif.bss_conf.channel_type;

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			break;

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		case NL80211_CHAN_HT40PLUS:

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			WARN_ON(superchan == NL80211_CHAN_HT40MINUS);

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			superchan = NL80211_CHAN_HT40PLUS;

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			break;

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		case NL80211_CHAN_HT40MINUS:

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			WARN_ON(superchan == NL80211_CHAN_HT40PLUS);

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			superchan = NL80211_CHAN_HT40MINUS;

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			break;

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		}

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	}

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	switch (superchan) {

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	case NL80211_CHAN_NO_HT:

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	case NL80211_CHAN_HT20:

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		/*

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		 * allow any change that doesn't go to no-HT

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		 * (if it already is no-HT no change is needed)

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		 */

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		if (chantype == NL80211_CHAN_NO_HT)

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			break;

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		superchan = chantype;

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		break;

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	case NL80211_CHAN_HT40PLUS:

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	case NL80211_CHAN_HT40MINUS:

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		/* allow smaller bandwidth and same */

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		if (chantype == NL80211_CHAN_NO_HT)

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			break;

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		if (chantype == NL80211_CHAN_HT20)

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			break;

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		if (superchan == chantype)

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			break;

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		result = false;

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		goto out;

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	}

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	local->_oper_channel_type = superchan;

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	if (sdata)

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		sdata->vif.bss_conf.channel_type = chantype;

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	result = true;

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 out:

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	mutex_unlock(&local->iflist_mtx);

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	return result;

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}

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