hostapd: generate unique SSID for SoftAP

If two or more targets are in the same environment, all of them will
broadcast the same SSID, which may be a problem when a client wants
to connect to a specific device.

Use the last bytes of the non-virtual wireless MAC for the name of the
SSID, a random value with no hexadecimal characters is used if the MAC
is not available.
Also drop 'wpa2aes' from the SSID.

https://jira.digi.com/browse/DEL-4129

Signed-off-by: Jose Diaz de Grenu <Jose.DiazdeGrenu@digi.com>

meta-digi-dey/recipes-connectivity/hostapd/hostapd/ccimx6ul/hostapd_wlan1.conf

@@ -4,7 +4,7 @@ interface=wlan1
 driver=nl80211
 
 # WPA2-AES encryption
-ssid=ap-wlan1-wpa2aes_a
+ssid=ap-wlan1-##MAC##
 auth_algs=1
 wpa=2
 wpa_key_mgmt=WPA-PSK

meta-digi-dey/recipes-connectivity/hostapd/hostapd/hostapd_wlan0.conf

@@ -4,7 +4,7 @@ interface=wlan0
 driver=nl80211
 
 # WPA2-AES encryption
-ssid=ap-wlan0-wpa2aes_a
+ssid=ap-wlan0-##MAC##
 auth_algs=1
 wpa=2
 wpa_key_mgmt=WPA-PSK

meta-digi-dey/recipes-connectivity/hostapd/hostapd_%.bbappend

@@ -17,5 +17,30 @@ do_install_append_ccimx6ul() {
 	install -m 0644 ${WORKDIR}/hostapd_wlan1.conf ${D}${sysconfdir}
 }
 
+pkg_postinst_${PN}() {
+	# Append the last two bytes of the wlan0 MAC address to the SSID of the
+	# hostAP configuration files
+	# (execute on first boot)
+	if [ -n "$D" ]; then
+		exit 1
+	fi
+
+	# Get the last two bytes of the wlan0 MAC address
+	MAC="$(cut -d ':' -f5,6 /sys/class/net/wlan0/address | tr -d ':')"
+
+	# If wlan0 is not available, use a random value with no hexadecimal characters
+	if [ -z "${MAC}" ]; then
+		MAC="$(cat /dev/urandom | tr -dc 'G-Z' | fold -w 4 | head -n 1)"
+	fi
+
+	find "${sysconfdir}" -type f -name 'hostapd_wlan?.conf' -exec \
+		sed -i -e "s,##MAC##,${MAC},g" {} \;
+
+	# Create the symlinks in the different runlevels
+	if type update-rc.d >/dev/null 2>/dev/null; then
+		update-rc.d ${INITSCRIPT_NAME} ${INITSCRIPT_PARAMS}
+	fi
+}
+
 # Do not autostart hostapd daemon, it will conflict with wpa-supplicant.
 INITSCRIPT_PARAMS = "remove"