FIX #2231 - Detect duplicate interfaces

Signed-off-by: David Gageot <david@gageot.net>

drivers/virtualbox/network.go

@@ -16,6 +16,7 @@ const (
 
 var (
 	reHostonlyInterfaceCreated            = regexp.MustCompile(`Interface '(.+)' was successfully created`)
+	errDuplicateHostOnlyInterfaceNetworks = errors.New("VirtualBox is configured with multiple host-only interfaces with the same IP. Please remove all of them but one.")
 )
 
 // Host-only network.
@@ -152,6 +153,10 @@ func getOrCreateHostOnlyNetwork(hostIP net.IP, netmask net.IPMask, dhcpIP net.IP
 		return nil, err
 	}
 
+	if len(nets) != countUniqueIps(nets) {
+		return nil, errDuplicateHostOnlyInterfaceNetworks
+	}
+
 	hostOnlyNet := getHostOnlyNetwork(nets, hostIP, netmask)
 	if hostOnlyNet != nil {
 		return hostOnlyNet, nil
@@ -182,6 +187,16 @@ func getOrCreateHostOnlyNetwork(hostIP net.IP, netmask net.IPMask, dhcpIP net.IP
 	return hostOnlyNet, nil
 }
 
+func countUniqueIps(nets map[string]*hostOnlyNetwork) int {
+	ips := map[string]bool{}
+
+	for _, n := range nets {
+		ips[n.IPv4.IP.String()] = true
+	}
+
+	return len(ips)
+}
+
 // DHCP server info.
 type dhcpServer struct {
 	NetworkName string

drivers/virtualbox/network_test.go

@@ -211,3 +211,15 @@ func TestGetHostOnlyNetwork(t *testing.T) {
 	assert.Equal(t, "HostInterfaceNetworking-vboxnet0", net.NetworkName)
 	assert.NoError(t, err)
 }
+
+func TestFailWithDuplicateHostOnlyNetworks(t *testing.T) {
+	vbox := &VBoxManagerMock{
+		args:   "list hostonlyifs",
+		stdOut: stdOutTwoHostOnlyNetwork,
+	}
+
+	net, err := getOrCreateHostOnlyNetwork(net.ParseIP("192.168.99.1"), parseIPv4Mask("255.255.255.0"), nil, nil, nil, vbox)
+
+	assert.Nil(t, net)
+	assert.Equal(t, errDuplicateHostOnlyInterfaceNetworks, err)
+}