-c will not fallback automatically

lnxrouter

@@ -88,7 +88,7 @@ Options:
                             Using this you can't use same wlan interface
                             for both Internet and AP
     --virt-name <name>      Set name of virtual interface
-    -c <channel>            Channel number (default: 1)
+    -c <channel>            Specify channel (default: use current one, or 1 / 36)
     --country <code>        Set two-letter country code for regularity
                             (example: US)
     --freq-band <GHz>       Set frequency band: 2.4 or 5 (default: 2.4)
@@ -1571,14 +1571,6 @@ check_wifi_settings() {
         exit 1
     fi
 
-    if [[ $CHANNEL == default ]]; then
-        if [[ $FREQ_BAND == 2.4 ]]; then
-            CHANNEL=1
-        else
-            CHANNEL=36
-        fi
-    fi
-
     if [[ $FREQ_BAND != 5 && $CHANNEL -gt 14 ]]; then
         echo "Channel number is greater than 14, assuming 5GHz frequency band"
         FREQ_BAND=5
@@ -1697,20 +1689,21 @@ prepare_wifi_interface() {
     
     if [[ $NO_VIRT -eq 0 ]]; then
     ## Will generate virtual wifi interface
+    
+        # TODO move this to check_wifi_settings() ?
         if is_interface_wifi_connected ${WIFI_IFACE}; then
             WIFI_IFACE_FREQ=$(iw dev ${WIFI_IFACE} link | grep -i freq | awk '{print $2}')
             WIFI_IFACE_CHANNEL=$(ieee80211_frequency_to_channel ${WIFI_IFACE_FREQ})
-            echo "${WIFI_IFACE} already in channel ${WIFI_IFACE_CHANNEL} (${WIFI_IFACE_FREQ} MHz)"
-            if is_5ghz_frequency $WIFI_IFACE_FREQ; then
-                FREQ_BAND=5
-            else
-                FREQ_BAND=2.4
-            fi
-            if [[ $WIFI_IFACE_CHANNEL -ne $CHANNEL ]]; then
-                echo "Channel fallback to ${WIFI_IFACE_CHANNEL}"
+            
+            echo "${WIFI_IFACE} already working in channel ${WIFI_IFACE_CHANNEL} (${WIFI_IFACE_FREQ} MHz)"
+            
+            if [[ $CHANNEL == default ]]; then
+                echo "Use wifi adapter current channel $WIFI_IFACE_CHANNEL as target channel"
                 CHANNEL=$WIFI_IFACE_CHANNEL
-            else
-                echo
+            fi
+            
+            if [[ $WIFI_IFACE_CHANNEL -ne $CHANNEL ]]; then
+                echo "WARN: Wifi adapter already working in channel ${WIFI_IFACE_CHANNEL}, which is different than target channel $CHANNEL" >&2
             fi
         fi
 
@@ -1736,6 +1729,15 @@ prepare_wifi_interface() {
     else # no virtual wifi interface, use wifi device interface itself
         AP_IFACE=${WIFI_IFACE}
     fi
+    
+    if [[ $CHANNEL == default ]]; then
+        echo "Channel not specified, use default"
+        if [[ $FREQ_BAND == 2.4 ]]; then
+            CHANNEL=1
+        else
+            CHANNEL=36
+        fi
+    fi
 }
 
 decide_subnet_interface() {