network: Assign "static" MAC addresses to QMI interfaces

This is really badly hacky, but I do not know a better way to solve this
with our existing "setup" program which would be a nightmare to extend.

So we are using the device number to generate a static MAC address which
can then be used as usual. I doubt many people will have more than one
device.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

src/initscripts/networking/functions.network

@@ -179,7 +179,7 @@ qmi_find_device() {
 	local path
 	for path in /dev/cdc-*; do
 		if [ -c "${path}" ]; then
-			_intf="$(qmicli --device="${path}" --device-open-proxy --get-wwan-iface)"
+			_intf="$(qmi_find_interface "${path}")"
 
 			# Check if the interface matches
 			if [ "${intf}" = "${_intf}" ]; then
@@ -193,6 +193,12 @@ qmi_find_device() {
 	return 1
 }
 
+qmi_find_interface() {
+	local device="${1}"
+
+	qmicli --device="${device}" --device-open-proxy --get-wwan-iface
+}
+
 qmi_enable_rawip_mode() {
 	local intf="${1}"
 
@@ -259,3 +265,19 @@ qmi_reset() {
 	qmicli --device="${device}" --device-open-proxy \
 		--wds-reset
 }
+
+# Assigns a "static" MAC address
+qmi_assign_address() {
+	local intf="${1}"
+
+	# Find the device
+	local device="$(qmi_find_device "${intf}")"
+
+	local address
+
+	# Generate a "random" MAC address using the device number
+	printf -v address "02:ff:ff:ff:ff:%02x" "${device:12}"
+
+	# Change the MAC address
+	ip link set "${intf}" address "${address}"
+}