link executor: Add support for dummy interfaces.

closes #49

Signed-off-by: Maximilian Wilhelm <max@sdn.clinic>

doc/interfaces.scd

@@ -66,6 +66,10 @@ the system will only respond to certain keywords by default:
 	is for backwards compatibility and should not be used in new
 	deployments.
 
+*link-type* _link-type_
+	Denotes the link-type of the interface. When set to _dummy_,
+	the interface is created as a virtual dummy interfaces.
+
 *requires* _interfaces_...
 	Designates one or more required interfaces that must be
 	brought up before configuration of the parent interface.
@@ -165,3 +169,4 @@ iface eth0
 # AUTHORS
 
 Ariadne Conill <ariadne@dereferenced.org>
+Maximilian Wilhelm <max@sdn.clinic>

executor-scripts/linux/link

@@ -32,6 +32,11 @@ is_vlan() {
 }
 
 case "$PHASE" in
+pre-up)
+	if [ "${IF_LINK_TYPE}" = "dummy" ]; then
+		ip link add "${IFACE}" type dummy
+	fi
+	;;
 up|down)
 	if is_vlan; then
 		ADD_DEL="add"