Fix subnet routers

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Target Go 1.19 for Headscale [#778](https://github.com/juanfont/headscale/pull/778)
 - Target Tailscale v1.30.0 to build Headscale [#780](https://github.com/juanfont/headscale/pull/780)
 - Give a warning when running Headscale with reverse proxy improperly configured for WebSockets [#788](https://github.com/juanfont/headscale/pull/788)
+- Fix subnet routers with Primary Routes [#811](https://github.com/juanfont/headscale/pull/811)
 
 ## 0.16.4 (2022-08-21)
 

machine.go

@@ -26,15 +26,22 @@ const (
 	)
 	ErrCouldNotConvertMachineInterface = Error("failed to convert machine interface")
 	ErrHostnameTooLong                 = Error("Hostname too long")
-	ErrDifferentRegisteredNamespace    = Error("machine was previously registered with a different namespace")
-	MachineGivenNameHashLength         = 8
-	MachineGivenNameTrimSize           = 2
+	ErrDifferentRegisteredNamespace    = Error(
+		"machine was previously registered with a different namespace",
+	)
+	MachineGivenNameHashLength = 8
+	MachineGivenNameTrimSize   = 2
 )
 
 const (
 	maxHostnameLength = 255
 )
 
+var (
+	ExitRouteV4 = netip.MustParsePrefix("0.0.0.0/0")
+	ExitRouteV6 = netip.MustParsePrefix("::/0")
+)
+
 // Machine is a Headscale client.
 type Machine struct {
 	ID          uint64 `gorm:"primary_key"`
@@ -633,10 +640,22 @@ func (machine Machine) toNode(
 		[]netip.Prefix{},
 		addrs...) // we append the node own IP, as it is required by the clients
 
-	// TODO(kradalby): Needs investigation, We probably dont need this condition
-	// now that we dont have shared nodes
-	if includeRoutes {
-		allowedIPs = append(allowedIPs, machine.EnabledRoutes...)
+	allowedIPs = append(allowedIPs, machine.EnabledRoutes...)
+
+	// TODO(kradalby): This is kind of a hack where we say that
+	// all the announced routes (except exit), is presented as primary
+	// routes. This might be problematic if two nodes expose the same route.
+	// This was added to address an issue where subnet routers stopped working
+	// when we only populated AllowedIPs.
+	primaryRoutes := []netip.Prefix{}
+	if len(machine.EnabledRoutes) > 0 {
+		for _, route := range machine.EnabledRoutes {
+			if route == ExitRouteV4 || route == ExitRouteV6 {
+				continue
+			}
+
+			primaryRoutes = append(primaryRoutes, route)
+		}
 	}
 
 	var derp string
@@ -683,16 +702,17 @@ func (machine Machine) toNode(
 		StableID: tailcfg.StableNodeID(
 			strconv.FormatUint(machine.ID, Base10),
 		), // in headscale, unlike tailcontrol server, IDs are permanent
-		Name:       hostname,
-		User:       tailcfg.UserID(machine.NamespaceID),
-		Key:        nodeKey,
-		KeyExpiry:  keyExpiry,
-		Machine:    machineKey,
-		DiscoKey:   discoKey,
-		Addresses:  addrs,
-		AllowedIPs: allowedIPs,
-		Endpoints:  machine.Endpoints,
-		DERP:       derp,
+		Name:          hostname,
+		User:          tailcfg.UserID(machine.NamespaceID),
+		Key:           nodeKey,
+		KeyExpiry:     keyExpiry,
+		Machine:       machineKey,
+		DiscoKey:      discoKey,
+		Addresses:     addrs,
+		AllowedIPs:    allowedIPs,
+		PrimaryRoutes: primaryRoutes,
+		Endpoints:     machine.Endpoints,
+		DERP:          derp,
 
 		Online:   &online,
 		Hostinfo: hostInfo.View(),
@@ -807,7 +827,8 @@ func (h *Headscale) RegisterMachineFromAuthCallback(
 			}
 
 			// Registration of expired machine with different namespace
-			if registrationMachine.ID != 0 && registrationMachine.NamespaceID != namespace.ID {
+			if registrationMachine.ID != 0 &&
+				registrationMachine.NamespaceID != namespace.ID {
 				return nil, ErrDifferentRegisteredNamespace
 			}