Return ErrNoGateway when all default routes have an On-link gateway

gateway_parsers.go

@@ -272,6 +272,9 @@ func parseWindowsGatewayIPs(output []byte) ([]net.IP, error) {
 		}
 		result = append(result, ip)
 	}
+	if len(result) == 0 {
+		return nil, &ErrNoGateway{}
+	}
 	return result, nil
 }
 

gateway_test.go

@@ -54,6 +54,7 @@ func TestParseWindows(t *testing.T) {
 		{randomData, false, "", &ErrCantParse{}},
 		{windowsNoRoute, false, "", &ErrNoGateway{}},
 		{windowsNoDefaultRoute, false, "", &ErrNoGateway{}},
+		{windowsOnLinkDefaultRoute, false, "", &ErrNoGateway{}},
 		{windowsBadRoute1, false, "", &ErrCantParse{}},
 		{windowsBadRoute2, false, "", &ErrCantParse{}},
 	}
@@ -71,6 +72,7 @@ func TestParseWindows(t *testing.T) {
 		{randomData, false, "", &ErrCantParse{}},
 		{windowsNoRoute, false, "", &ErrNoGateway{}},
 		{windowsNoDefaultRoute, false, "", &ErrNoGateway{}},
+		{windowsOnLinkDefaultRoute, true, "192.0.2.5", nil},
 		{windowsBadRoute1, false, "", &ErrCantParse{}},
 		{windowsBadRoute2, true, "10.88.88.149", nil},
 	}

route-tables/windowsOnLinkDefaultRoute.txt

@@ -0,0 +1,26 @@
+===========================================================================
+Interface List
+ 43..........................._Common_na_vpn
+ 50...00 42 42 42 42 42 ......Hyper-V Virtual Ethernet Adapter
+ 13...42 42 42 42 42 42 ......Intel(R) Wi-Fi otters #2
+ 10...42 42 42 42 42 48 ......Intel(R) Wi-Fi otters #5
+ 12...42 42 42 42 42 42 ......Intel(R) Wi-Fi otters
+  8...42 42 42 42 42 40 ......Bluetooth Device (Personal Area Network)
+  1...........................Software Loopback Interface 1
+===========================================================================
+
+IPv4 Route Table
+===========================================================================
+Active Routes:
+Network Destination        Netmask          Gateway       Interface  Metric
+          0.0.0.0          0.0.0.0         On-link      192.0.2.5         1
+===========================================================================
+Persistent Routes:
+  None
+
+IPv6 Route Table
+===========================================================================
+Active Routes:
+  None
+Persistent Routes:
+  None