3117bbdb78
When regulatory information changes our HT behavior (e.g, when we get a country code from the AP we have just associated with), we should use this information to change the power with which we transmit, and what channels we transmit. Sometimes the channel parameters we derive from regulatory information contradicts the parameters we used in association. For example, we could have associated specifying HT40, but the regulatory rules we apply may forbid HT40 operation. In the situation above, we should reconfigure ourselves to transmit in HT20 only, however it makes no sense for us to disable receive in HT40, since if we associated with these parameters, the AP has every reason to expect we can and will receive packets this way. The code in mac80211 does not have the capability of sending the appropriate action frames to signal a change in HT behaviour so the AP has no clue we can no longer receive frames encoded this way. In some broken AP implementations, this can leave us effectively deaf if the AP never retries in lower HT rates. This change breaks up the channel_type parameter in the ieee80211_enable_ht function into a separate receive and transmit part. It honors the channel flags set by regulatory in order to configure the rate control algorithm, but uses the capability flags to configure the channel on the radio, since these were used in association to set the AP's transmit rate. Signed-off-by: Paul Stewart <pstew@chromium.org> Cc: Sam Leffler <sleffler@chromium.org> Cc: Johannes Berg <johannes@sipsolutions.net> Reviewed-by: Luis R Rodriguez <mcgrof@frijolero.org> Signed-off-by: John W. Linville <linville@tuxdriver.com>
164 lines
3.6 KiB
C
164 lines
3.6 KiB
C
/*
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* mac80211 - channel management
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*/
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#include <linux/nl80211.h>
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#include <net/cfg80211.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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switch (sdata->vif.type) {
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case NL80211_IFTYPE_MONITOR:
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continue;
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case NL80211_IFTYPE_STATION:
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if (!sdata->u.mgd.associated)
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continue;
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break;
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case 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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break;
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case NL80211_IFTYPE_AP_VLAN:
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/* will also have _AP interface */
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continue;
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case NL80211_IFTYPE_AP:
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if (!sdata->u.ap.beacon)
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continue;
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break;
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default:
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break;
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}
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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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/*
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* ieee80211_get_tx_channel_type returns the channel type we should
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* use for packet transmission, given the channel capability and
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* whatever regulatory flags we have been given.
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*/
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enum nl80211_channel_type ieee80211_get_tx_channel_type(
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struct ieee80211_local *local,
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enum nl80211_channel_type channel_type)
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{
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switch (channel_type) {
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case NL80211_CHAN_HT40PLUS:
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if (local->hw.conf.channel->flags &
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IEEE80211_CHAN_NO_HT40PLUS)
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return NL80211_CHAN_HT20;
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break;
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case NL80211_CHAN_HT40MINUS:
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if (local->hw.conf.channel->flags &
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IEEE80211_CHAN_NO_HT40MINUS)
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return NL80211_CHAN_HT20;
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break;
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default:
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break;
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}
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return channel_type;
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}
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