Do not disable 40 MHz based on co-ex report with matching primary channel

When processing 20/40 BSS Coexistence Management frames that do not
explicitly require 40 MHz to be disabled, check whether the reported
channels in 20/40 BSS Intolerant Channel Report element match the
current primary channel. If so, allow 40 MHz operation to continue. This
makes the during-operation updates for 20/40 Operation Permitted more
consistent with the scans during initial BSS startup.

The received 20/40 BSS Intolerant Channel Report channels are to be used
in the OT set in the during-operation determination and the P == OT_i
exception was ignored in the previous implementation which could result
in the AP first starting with 40 MHz and then dropping to 20 MHz on
first received 20/40 BSS Coexistence Management frame even though there
was no change in the neighboring BSSs.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

diff --git a/src/ap/ieee802_11_ht.c b/src/ap/ieee802_11_ht.c
index 27f3885880b319de9617dc67078420ef9c5c4a9c..214855dccb8cf9c8319641b19f9217f210626d1d 100644 (file)
--- a/src/ap/ieee802_11_ht.c
+++ b/src/ap/ieee802_11_ht.c
@@ -332,8 +332,10 @@ void hostapd_2040_coex_action(struct hostapd_data *hapd,
                for (i = 0; i < ielen - 1; i++) {
                        u8 chan = ic_report->variable[i];
 
+                       if (chan == iface->conf->channel)
+                               continue; /* matching own primary channel */
                        if (is_40_allowed(iface, chan))
-                               continue;
+                               continue; /* not within affected channels */
                        hostapd_logger(hapd, mgmt->sa,
                                       HOSTAPD_MODULE_IEEE80211,
                                       HOSTAPD_LEVEL_DEBUG,