network: add support for CIDR addresses Debian routes

OnMetal is changing their template from:
`route add -net 1.2.3.0 netmask 255.255.255.0 gw 10.1.2.1 || true`
to:
`route add -net 1.2.3.0/24 gw 10.1.2.1 || true`

network/stanza.go

@@ -236,7 +236,11 @@ func parseInterfaceStanza(attributes []string, options []string) (*stanzaInterfa
 				for i, field := range fields[:len(fields)-1] {
 					switch field {
 					case "-net":
+						if _, dst, err := net.ParseCIDR(fields[i+1]); err == nil {
+							route.destination = *dst
+						} else {
 							route.destination.IP = net.ParseIP(fields[i+1])
+						}
 					case "netmask":
 						route.destination.Mask = net.IPMask(net.ParseIP(fields[i+1]).To4())
 					case "gw":

network/stanza_test.go

@@ -285,12 +285,17 @@ func TestBadParseInterfaceStanzasStaticPostUp(t *testing.T) {
 }
 
 func TestParseInterfaceStanzaStaticPostUp(t *testing.T) {
-	options := []string{
+	for _, tt := range []struct {
+		options []string
+		expect  []route
+	}{
+		{
+			options: []string{
 				"address 192.168.1.100",
 				"netmask 255.255.255.0",
 				"post-up route add gw 192.168.1.1 -net 192.168.1.0 netmask 255.255.255.0",
-	}
+			},
-	expect := []route{
+			expect: []route{
 				{
 					destination: net.IPNet{
 						IP:   net.IPv4(192, 168, 1, 0),
@@ -298,18 +303,39 @@ func TestParseInterfaceStanzaStaticPostUp(t *testing.T) {
 					},
 					gateway: net.IPv4(192, 168, 1, 1),
 				},
+			},
+		},
+		{
+			options: []string{
+				"address 192.168.1.100",
+				"netmask 255.255.255.0",
+				"post-up route add gw 192.168.1.1 -net 192.168.1.0/24 || true",
+			},
+			expect: []route{
+				{
+					destination: func() net.IPNet {
+						if _, net, err := net.ParseCIDR("192.168.1.0/24"); err == nil {
+							return *net
+						} else {
+							panic(err)
 						}
-
+					}(),
-	iface, err := parseInterfaceStanza([]string{"eth", "inet", "static"}, options)
+					gateway: net.IPv4(192, 168, 1, 1),
+				},
+			},
+		},
+	} {
+		iface, err := parseInterfaceStanza([]string{"eth", "inet", "static"}, tt.options)
 		if err != nil {
-		t.FailNow()
+			t.Fatalf("bad error (%+v): want nil, got %s\n", tt, err)
 		}
 		static, ok := iface.configMethod.(configMethodStatic)
 		if !ok {
-		t.FailNow()
+			t.Fatalf("bad config method (%+v): want configMethodStatic, got %T\n", tt, iface.configMethod)
+		}
+		if !reflect.DeepEqual(static.routes, tt.expect) {
+			t.Fatalf("bad routes (%+v): want %#v, got %#v\n", tt, tt.expect, static.routes)
 		}
-	if !reflect.DeepEqual(static.routes, expect) {
-		t.FailNow()
 	}
 }