Refactor limayaml.FirstUsernetIndex implementation and usages

pkg/hostagent/hostagent.go

@@ -305,8 +305,7 @@ func (a *HostAgent) Run(ctx context.Context) error {
 	}()
 	adjustNofileRlimit()
 
-	firstUsernetIndex := limayaml.FirstUsernetIndex(a.y)
-	if firstUsernetIndex == -1 && *a.y.HostResolver.Enabled {
+	if limayaml.FirstUsernetIndex(a.y) == -1 && *a.y.HostResolver.Enabled {
 		hosts := a.y.HostResolver.Hosts
 		hosts["host.lima.internal"] = networks.SlirpGateway
 		hosts[fmt.Sprintf("lima-%s", a.instName)] = networks.SlirpIPAddress

pkg/limayaml/defaults.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"slices"
 	"strconv"
 	"strings"
 	"text/template"
@@ -90,14 +91,7 @@ func defaultContainerdArchives() []File {
 
 // FirstUsernetIndex gets the index of first usernet network under l.Network[]. Returns -1 if no usernet network found
 func FirstUsernetIndex(l *LimaYAML) int {
-	for i := range l.Networks {
-		nwName := l.Networks[i].Lima
-		isUsernet, _ := networks.Usernet(nwName)
-		if isUsernet {
-			return i
-		}
-	}
-	return -1
+	return slices.IndexFunc(l.Networks, func(network Network) bool { return networks.IsUsernet(network.Lima) })
 }
 
 func MACAddress(uniqueID string) string {

pkg/networks/config.go

@@ -171,11 +171,16 @@ func Sock(name string) (string, error) {
 	return cache.config.Sock(name), nil
 }
 
-// Usernet Returns true if the given network name is usernet network
-func Usernet(name string) (bool, error) {
+// IsUsernet returns true if the given network name is a usernet network.
+// It return false if the cache cannot be loaded or the network is not defined.
+func IsUsernet(name string) bool {
 	loadCache()
 	if cache.err != nil {
-		return false, cache.err
+		return false
 	}
-	return cache.config.Usernet(name)
+	isUsernet, err := cache.config.Usernet(name)
+	if err != nil {
+		return false
+	}
+	return isUsernet
 }

pkg/vz/vm_darwin.go

@@ -124,37 +124,36 @@ func startVM(ctx context.Context, driver *driver.BaseDriver) (*virtualMachineWra
 }
 
 func startUsernet(ctx context.Context, driver *driver.BaseDriver) (*usernet.Client, error) {
-	firstUsernetIndex := limayaml.FirstUsernetIndex(driver.Yaml)
-	if firstUsernetIndex == -1 {
-		// Start a in-process gvisor-tap-vsock
-		endpointSock, err := usernet.SockWithDirectory(driver.Instance.Dir, "", usernet.EndpointSock)
-		if err != nil {
-			return nil, err
-		}
-		vzSock, err := usernet.SockWithDirectory(driver.Instance.Dir, "", usernet.FDSock)
-		if err != nil {
-			return nil, err
-		}
-		os.RemoveAll(endpointSock)
-		os.RemoveAll(vzSock)
-		err = usernet.StartGVisorNetstack(ctx, &usernet.GVisorNetstackOpts{
-			MTU:      1500,
-			Endpoint: endpointSock,
-			FdSocket: vzSock,
-			Async:    true,
-			DefaultLeases: map[string]string{
-				networks.SlirpIPAddress: limayaml.MACAddress(driver.Instance.Dir),
-			},
-			Subnet: networks.SlirpNetwork,
-		})
-		if err != nil {
-			return nil, err
-		}
-		subnetIP, _, err := net.ParseCIDR(networks.SlirpNetwork)
-		return usernet.NewClient(endpointSock, subnetIP), err
+	if firstUsernetIndex := limayaml.FirstUsernetIndex(driver.Yaml); firstUsernetIndex != -1 {
+		nwName := driver.Yaml.Networks[firstUsernetIndex].Lima
+		return usernet.NewClientByName(nwName), nil
+	}
+	// Start a in-process gvisor-tap-vsock
+	endpointSock, err := usernet.SockWithDirectory(driver.Instance.Dir, "", usernet.EndpointSock)
+	if err != nil {
+		return nil, err
+	}
+	vzSock, err := usernet.SockWithDirectory(driver.Instance.Dir, "", usernet.FDSock)
+	if err != nil {
+		return nil, err
+	}
+	os.RemoveAll(endpointSock)
+	os.RemoveAll(vzSock)
+	err = usernet.StartGVisorNetstack(ctx, &usernet.GVisorNetstackOpts{
+		MTU:      1500,
+		Endpoint: endpointSock,
+		FdSocket: vzSock,
+		Async:    true,
+		DefaultLeases: map[string]string{
+			networks.SlirpIPAddress: limayaml.MACAddress(driver.Instance.Dir),
+		},
+		Subnet: networks.SlirpNetwork,
+	})
+	if err != nil {
+		return nil, err
 	}
-	nwName := driver.Yaml.Networks[firstUsernetIndex].Lima
-	return usernet.NewClientByName(nwName), nil
+	subnetIP, _, err := net.ParseCIDR(networks.SlirpNetwork)
+	return usernet.NewClient(endpointSock, subnetIP), err
 }
 
 func createVM(driver *driver.BaseDriver) (*vz.VirtualMachine, error) {