Check in `iw phy phyX info' if we can transmit to the selected channel

create_ap

@@ -76,6 +76,41 @@ version_cmp() {
     return 0
 }
 
+get_phy_device() {
+    for x in /sys/class/ieee80211/*; do
+        [[ ! -d "$x" ]] && continue
+        if [[ "${x##*/}" = "$1" ]]; then
+            echo $1
+            return 0
+        elif [[ -e "$x/device/net/$1" ]]; then
+            echo ${x##*/}
+            return 0
+        elif [[ -e "$x/device/net:$1" ]]; then
+            echo ${x##*/}
+            return 0
+        fi
+    done
+    echo "Failed to get phy interface" >&2
+    return 1
+}
+
+get_adapter_info() {
+    PHY=$(get_phy_device "$1")
+    [[ $? -ne 0 ]] && return 1
+    iw phy $PHY info
+}
+
+can_transmit_to_channel() {
+    IFACE=$1
+    CHANNEL=$2
+    CHANNEL_INFO=$(get_adapter_info ${IFACE} | grep "MHz \[${CHANNEL}\]")
+
+    [[ -z "${CHANNEL_INFO}" ]] && return 1
+    [[ "${CHANNEL_INFO}" == *no\ IR* ]] && return 1
+    [[ "${CHANNEL_INFO}" == *disabled* ]] && return 1
+    return 0
+}
+
 get_macaddr() {
     ip link show "$1" | grep ether | grep -Eo '([0-9a-f]{2}:){5}[0-9a-f]{2}[[:space:]]' | tr -d '[[:space:]]'
 }
@@ -426,6 +461,8 @@ else
     [[ "$WIFI_IFACE" == "$INTERNET_IFACE" ]] && die "You can not share your connection from the same interface if you are using --no-virt option."
 fi
 
+can_transmit_to_channel ${WIFI_IFACE} ${CHANNEL} || die "Your adapter can not transmit to channel $CHANNEL."
+
 networkmanager_add_unmanaged ${WIFI_IFACE}
 
 [[ $HIDDEN -eq 1 ]] && echo "Access Point's SSID is hidden!"