f-28: refactor dhcp config to use VPCRoute and DefaultGateway

Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>

internal/dhcp/dhcp_test.go

@@ -51,10 +51,13 @@ func TestIncrementIP_Carry(t *testing.T) {
 func newConf(t *testing.T, cidr string) Config {
 	t.Helper()
 	_, network, _ := net.ParseCIDR(cidr)
+	_, vpcNet, _ := net.ParseCIDR("10.0.0.0/16")
+	gw := net.ParseIP("192.168.1.1").To4()
 	return Config{
 		Network:        network,
-		Gateway:      net.ParseIP("192.168.1.1").To4(),
+		VPCGateway:     gw,
-		DefaultRoute: true,
+		VPCRoute:       vpcNet,
+		DefaultGateway: gw,
 		Name:           "test",
 		ConfDir:        t.TempDir(),
 	}
@@ -85,24 +88,45 @@ func TestGenerateConfig_FilenameMatchesName(t *testing.T) {
 	}
 }
 
-func TestGenerateConfig_ContainsGateway(t *testing.T) {
+func TestGenerateConfig_ContainsDefaultGateway(t *testing.T) {
 	conf := newConf(t, "192.168.1.0/29")
 	path, _, _ := GenerateConfig(conf)
 	content, _ := os.ReadFile(path)
 
 	if !strings.Contains(string(content), "dhcp-option=3,192.168.1.1") {
-		t.Errorf("gateway absente du fichier généré :\n%s", content)
+		t.Errorf("dhcp-option=3 absente du fichier généré :\n%s", content)
 	}
 }
 
-func TestGenerateConfig_NoDefaultRoute(t *testing.T) {
+func TestGenerateConfig_NoDefaultGateway(t *testing.T) {
 	conf := newConf(t, "192.168.1.0/29")
-	conf.DefaultRoute = false
+	conf.DefaultGateway = nil
 	path, _, _ := GenerateConfig(conf)
 	content, _ := os.ReadFile(path)
 
 	if strings.Contains(string(content), "dhcp-option=3,") {
-		t.Errorf("dhcp-option=3 présente alors que DefaultRoute=false :\n%s", content)
+		t.Errorf("dhcp-option=3 présente alors que DefaultGateway=nil :\n%s", content)
+	}
+}
+
+func TestGenerateConfig_ContainsVPCRoute(t *testing.T) {
+	conf := newConf(t, "192.168.1.0/29")
+	path, _, _ := GenerateConfig(conf)
+	content, _ := os.ReadFile(path)
+
+	if !strings.Contains(string(content), "dhcp-option=121,10.0.0.0/16,192.168.1.1") {
+		t.Errorf("dhcp-option=121 absente ou incorrecte :\n%s", content)
+	}
+}
+
+func TestGenerateConfig_NoVPCRoute(t *testing.T) {
+	conf := newConf(t, "192.168.1.0/29")
+	conf.VPCRoute = nil
+	path, _, _ := GenerateConfig(conf)
+	content, _ := os.ReadFile(path)
+
+	if strings.Contains(string(content), "dhcp-option=121,") {
+		t.Errorf("dhcp-option=121 présente alors que VPCRoute=nil :\n%s", content)
 	}
 }
 
@@ -110,7 +134,6 @@ func TestGenerateConfig_ContainsDhcpRange(t *testing.T) {
 	_, network, _ := net.ParseCIDR("10.10.0.0/24")
 	conf := Config{
 		Network: network,
-		Gateway: net.ParseIP("10.10.0.1").To4(),
 		Name:    "vpc1",
 		ConfDir: t.TempDir(),
 	}
@@ -156,7 +179,6 @@ func TestGenerateConfig_CreatesConfDir(t *testing.T) {
 	_, network, _ := net.ParseCIDR("10.0.0.0/30")
 	conf := Config{
 		Network: network,
-		Gateway: net.ParseIP("10.0.0.1").To4(),
 		Name:    "net",
 		ConfDir: dir,
 	}

internal/dhcp/generate.go

@@ -14,8 +14,11 @@ func GenerateConfig(c Config) (string, map[string]string, error) {
 	var sb strings.Builder
 	fmt.Fprintf(&sb, "no-resolv\n")
 	fmt.Fprintf(&sb, "dhcp-range=%s,static,%s,12h\n", c.Network.IP.String(), mask)
-	if c.DefaultRoute {
+	if c.VPCRoute != nil {
-		fmt.Fprintf(&sb, "dhcp-option=3,%s\n", c.Gateway.String())
+		fmt.Fprintf(&sb, "dhcp-option=121,%s,%s\n", c.VPCRoute.String(), c.VPCGateway.String())
+	}
+	if c.DefaultGateway != nil {
+		fmt.Fprintf(&sb, "dhcp-option=3,%s\n", c.DefaultGateway.String())
 	}
 	fmt.Fprintf(&sb, "dhcp-option=6,1.1.1.1,8.8.8.8\n\n")
 

internal/dhcp/struct.go

@@ -6,8 +6,9 @@ import (
 
 type Config struct {
 	Network        *net.IPNet
-	Gateway      net.IP
+	VPCGateway     net.IP     // next-hop for VPCRoute (option 121)
-	DefaultRoute bool
+	VPCRoute       *net.IPNet // if non-nil, emit dhcp-option=121,VPCRoute,VPCGateway
+	DefaultGateway net.IP     // if non-nil, emit dhcp-option=3,DefaultGateway
 	Name           string
 	ConfDir        string
 }

internal/subnet/create.go

@@ -137,11 +137,22 @@ func setupVxlanHost(d subnetData, vethE string) error {
 func startDHCP(db *badger.DB, subnetName string, d subnetData) error {
 	conf := dhcp.Config{
 		Network: d.cidr,
-		Gateway:      d.interfaceIP,
-		DefaultRoute: d.mode == "vxlan",
 		Name:    d.vpc + "_" + d.bridge,
 		ConfDir: "/etc/dnsmasq.d",
 	}
+	switch d.mode {
+	case "vxlan":
+		conf.VPCGateway = d.interfaceIP
+		conf.VPCRoute = d.vpcCIDR
+	case "bridge":
+		if d.defaultRoute {
+			gw, err := netif.GetDefaultGateway()
+			if err != nil {
+				return fmt.Errorf("get default gateway: %w", err)
+			}
+			conf.DefaultGateway = gw
+		}
+	}
 	_, entries, err := dhcp.GenerateConfig(conf)
 	if err != nil {
 		return fmt.Errorf("generate dhcp config: %w", err)