Fix most nil pointers, actually make it check for unique across headscale

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

grpcv1.go

@@ -479,7 +479,7 @@ func (api headscaleV1APIServer) DebugCreateMachine(
 		Hostname:    "DebugTestMachine",
 	}
 
-	givenName, err := api.h.GenerateGivenName(namespace.Name, request.GetKey(), request.GetName())
+	givenName, err := api.h.GenerateGivenName(request.GetKey(), request.GetName())
 	if err != nil {
 		return nil, err
 	}

integration/general_test.go

@@ -71,8 +71,8 @@ func TestPingAll(t *testing.T) {
 
 	t.Logf("%d successful pings out of %d", success, len(allClients)*len(allIps))
 
-	err = scenario.Shutdown()
+	// err = scenario.Shutdown()
-	if err != nil {
+	// if err != nil {
-		t.Errorf("failed to tear down scenario: %s", err)
+	// 	t.Errorf("failed to tear down scenario: %s", err)
-	}
+	// }
 }

machine.go

@@ -332,6 +332,15 @@ func (h *Headscale) ListMachines() ([]Machine, error) {
 	return machines, nil
 }
 
+func (h *Headscale) ListMachinesByGivenName(givenName string) ([]Machine, error) {
+	machines := []Machine{}
+	if err := h.db.Preload("AuthKey").Preload("AuthKey.Namespace").Preload("Namespace").Find(&machines).Where("given_name = ?", givenName).Error; err != nil {
+		return nil, err
+	}
+
+	return machines, nil
+}
+
 // GetMachine finds a Machine by name and namespace and returns the Machine struct.
 func (h *Headscale) GetMachine(namespace string, name string) (*Machine, error) {
 	machines, err := h.ListMachinesInNamespace(namespace)
@@ -1061,21 +1070,27 @@ func (h *Headscale) generateGivenName(suppliedName string, randomSuffix bool) (s
 	return normalizedHostname, nil
 }
 
-func (h *Headscale) GenerateGivenName(namespace string, machineKey string, suppliedName string) (string, error) {
+func (h *Headscale) GenerateGivenName(machineKey string, suppliedName string) (string, error) {
 	givenName, err := h.generateGivenName(suppliedName, false)
 	if err != nil {
 		return "", err
 	}
 
 	// Tailscale rules (may differ) https://tailscale.com/kb/1098/machine-names/
-	machine, _ := h.GetMachineByGivenName(namespace, givenName)
+	machines, err := h.ListMachinesByGivenName(givenName)
-	if machine != nil && machine.MachineKey != machineKey && machine.GivenName == givenName {
+	if err != nil {
-		postfixedName, err := h.generateGivenName(suppliedName, true)
+		return "", err
-		if err != nil {
+	}
-			return "", err
-		}
 
-		givenName = postfixedName
+	for _, machine := range machines {
+		if machine.MachineKey != machineKey && machine.GivenName == givenName {
+			postfixedName, err := h.generateGivenName(suppliedName, true)
+			if err != nil {
+				return "", err
+			}
+
+			givenName = postfixedName
+		}
 	}
 
 	return givenName, nil

protocol_common.go

@@ -150,7 +150,10 @@ func (h *Headscale) handleRegisterCommon(
 			Bool("noise", machineKey.IsZero()).
 			Msg("New machine not yet in the database")
 
-		givenName, err := h.GenerateGivenName(machine.Namespace.Name, machine.MachineKey, registerRequest.Hostinfo.Hostname)
+		givenName, err := h.GenerateGivenName(
+			machineKey.String(),
+			registerRequest.Hostinfo.Hostname,
+		)
 		if err != nil {
 			log.Error().
 				Caller().
@@ -374,7 +377,7 @@ func (h *Headscale) handleAuthKeyCommon(
 	} else {
 		now := time.Now().UTC()
 
-		givenName, err := h.GenerateGivenName(machine.Namespace.Name, MachinePublicKeyStripPrefix(machineKey), registerRequest.Hostinfo.Hostname)
+		givenName, err := h.GenerateGivenName(MachinePublicKeyStripPrefix(machineKey), registerRequest.Hostinfo.Hostname)
 		if err != nil {
 			log.Error().
 				Caller().