prefix.split('/')[0]

gre/files/tun.j2

@@ -15,7 +15,7 @@ iface {{ name }} inet tunnel
 	pre-up ip link set mtu {{ interface.mtu }} dev $IFACE
 	{%- endif %}
 	{%- for prefix in interface.prefixes %}
-	{% if salt['network.ip_in_subnet']( prefix..split('/')[0], "169.254.0.0/16" ) %}
+	{% if salt['network.ip_in_subnet']( prefix.split('/')[0], "169.254.0.0/16" ) %}
 	post-up ip address add {{ prefix }} dev $IFACE scope link
 	{%- else %}
 	address	{{ prefix }}