mac80211: improve HT channel handling
Currently, when one interface switches HT mode,
all others will follow along. This is clearly
undesirable, since the new one might switch to
no-HT while another one is operating in HT.
Address this issue by keeping track of the HT
mode per interface, and allowing only changes
that are compatible, i.e. switching into HT40+
is not possible when another interface is in
HT40-, in that case the second one needs to
fall back to HT20.
Also, to allow drivers to know what's going on,
store the per-interface HT mode (channel type)
in the virtual interface's bss_conf.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 08f3832..5d218c5 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -2,6 +2,7 @@
* mac80211 - channel management
*/
+#include <linux/nl80211.h>
#include "ieee80211_i.h"
enum ieee80211_chan_mode
@@ -55,3 +56,72 @@
return mode;
}
+
+bool ieee80211_set_channel_type(struct ieee80211_local *local,
+ struct ieee80211_sub_if_data *sdata,
+ enum nl80211_channel_type chantype)
+{
+ struct ieee80211_sub_if_data *tmp;
+ enum nl80211_channel_type superchan = NL80211_CHAN_NO_HT;
+ bool result;
+
+ mutex_lock(&local->iflist_mtx);
+
+ list_for_each_entry(tmp, &local->interfaces, list) {
+ if (tmp == sdata)
+ continue;
+
+ if (!ieee80211_sdata_running(tmp))
+ continue;
+
+ switch (tmp->vif.bss_conf.channel_type) {
+ case NL80211_CHAN_NO_HT:
+ case NL80211_CHAN_HT20:
+ superchan = tmp->vif.bss_conf.channel_type;
+ break;
+ case NL80211_CHAN_HT40PLUS:
+ WARN_ON(superchan == NL80211_CHAN_HT40MINUS);
+ superchan = NL80211_CHAN_HT40PLUS;
+ break;
+ case NL80211_CHAN_HT40MINUS:
+ WARN_ON(superchan == NL80211_CHAN_HT40PLUS);
+ superchan = NL80211_CHAN_HT40MINUS;
+ break;
+ }
+ }
+
+ switch (superchan) {
+ case NL80211_CHAN_NO_HT:
+ case NL80211_CHAN_HT20:
+ /*
+ * allow any change that doesn't go to no-HT
+ * (if it already is no-HT no change is needed)
+ */
+ if (chantype == NL80211_CHAN_NO_HT)
+ break;
+ superchan = chantype;
+ break;
+ case NL80211_CHAN_HT40PLUS:
+ case NL80211_CHAN_HT40MINUS:
+ /* allow smaller bandwidth and same */
+ if (chantype == NL80211_CHAN_NO_HT)
+ break;
+ if (chantype == NL80211_CHAN_HT20)
+ break;
+ if (superchan == chantype)
+ break;
+ result = false;
+ goto out;
+ }
+
+ local->_oper_channel_type = superchan;
+
+ if (sdata)
+ sdata->vif.bss_conf.channel_type = chantype;
+
+ result = true;
+ out:
+ mutex_unlock(&local->iflist_mtx);
+
+ return result;
+}