Make it possible to unregister vrf (#197)

* Add Unregister function to VRF to remove VRF from global registry

* Add test for Unregister

routingtable/vrf/vrf.go

@@ -26,7 +26,7 @@ type VRF struct {
 	ribNames map[string]*locRIB.LocRIB
 }
 
-// New creates a new VRF
+// New creates a new VRF. The VRF is registered automatically to the global VRF registry.
 func New(name string) (*VRF, error) {
 	v := newUntrackedVRF(name)
 	v.CreateIPv4UnicastLocRIB("inet.0")
@@ -89,6 +89,11 @@ func (v *VRF) Name() string {
 	return v.name
 }
 
+// Unregister removes this VRF from the global registry.
+func (v *VRF) Unregister() {
+	globalRegistry.unregisterVRF(v)
+}
+
 func (v *VRF) ribForAddressFamily(family addressFamily) *locRIB.LocRIB {
 	v.mu.Lock()
 	defer v.mu.Unlock()

routingtable/vrf/vrf_registry.go

@@ -13,11 +13,14 @@ func init() {
 	}
 }
 
+// vrfRegistry holds a reference to all active VRFs. Every VRF have to have a different name.
 type vrfRegistry struct {
 	vrfs map[string]*VRF
 	mu   sync.Mutex
 }
 
+// registerVRF adds the given VRF from the global registry.
+// An error is returned if there is already a VRF registered with the same name.
 func (r *vrfRegistry) registerVRF(v *VRF) error {
 	r.mu.Lock()
 	defer r.mu.Unlock()
@@ -30,3 +33,11 @@ func (r *vrfRegistry) registerVRF(v *VRF) error {
 	r.vrfs[v.name] = v
 	return nil
 }
+
+// unregisterVRF removes the given VRF from the global registry.
+func (r *vrfRegistry) unregisterVRF(v *VRF) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	delete(r.vrfs, v.name)
+}

routingtable/vrf/vrf_test.go

@@ -53,3 +53,21 @@ func TestName(t *testing.T) {
 	v := newUntrackedVRF("foo")
 	assert.Equal(t, "foo", v.Name())
 }
+
+func TestUnregister(t *testing.T) {
+	vrfName := "registeredVRF"
+	v, err := New(vrfName)
+	assert.Nil(t, err, "error must be nil on first invokation")
+
+	_, err = New(vrfName)
+	assert.NotNil(t, err, "error must not be nil on second invokation")
+
+	_, found := globalRegistry.vrfs[vrfName]
+	assert.True(t, found, "vrf must be in global registry")
+
+	v.Unregister()
+
+	_, found = globalRegistry.vrfs[vrfName]
+	assert.False(t, found, "vrf must not be in global registry")
+
+}