fix: check only for IPv4 in DNS lookup, fixes ddev#6592 (ddev#6593)

pkg/ddevapp/hostname_mgt.go

@@ -1,6 +1,7 @@
 package ddevapp
 
 import (
+	"context"
 	"fmt"
 	"net"
 	"os"
@@ -94,11 +95,11 @@ func (app *DdevApp) AddHostsEntriesIfNeeded() error {
 		if app.UseDNSWhenPossible && globalconfig.IsInternetActive() {
 			// If they have provided "*.<name>" then look up the suffix
 			checkName := strings.TrimPrefix(name, "*.")
-			hostIPs, err := net.LookupHost(checkName)
+			hostIPs, err := net.DefaultResolver.LookupIP(context.Background(), "ip4", checkName)
 
 			// If we had successful lookup and the IP address looked up is local
 			// then we don't have to add it to the /etc/hosts.
-			if err == nil && len(hostIPs) > 0 && netutil.IsLocalIP(hostIPs[0]) {
+			if err == nil && len(hostIPs) > 0 && netutil.HasLocalIP(hostIPs) {
 				continue
 			}
 		}

pkg/dockerutil/dockerutils.go

@@ -919,9 +919,9 @@ func GetDockerIP() (string, error) {
 				addr := net.ParseIP(hostPart)
 				if addr == nil {
 					// If it wasn't an IP address, look it up to get IP address
-					ip, err := net.LookupHost(hostPart)
+					ip, err := net.DefaultResolver.LookupIP(context.Background(), "ip4", hostPart)
 					if err == nil && len(ip) > 0 {
-						hostPart = ip[0]
+						hostPart = ip[0].String()
 					} else {
 						return "", fmt.Errorf("failed to look up IP address for $DOCKER_HOST=%s, hostname=%s: %v", dockerHostRawURL, hostPart, err)
 					}

pkg/globalconfig/global_config.go

@@ -817,7 +817,7 @@ var IsInternetActiveResult = false
 // In order to override net.DefaultResolver with a stub, we have to define an
 // interface on our own since there is none from the standard library.
 var IsInternetActiveNetResolver interface {
-	LookupHost(ctx context.Context, host string) (addrs []string, err error)
+	LookupIP(ctx context.Context, network, host string) ([]net.IP, error)
 } = net.DefaultResolver
 
 // IsInternetActive checks to see if we have a viable
@@ -837,7 +837,7 @@ func IsInternetActive() bool {
 	// Using a random URL is more conclusive, but it's more intrusive because
 	// DNS may take some time, and it's really annoying.
 	testURL := "test.ddev.site"
-	addrs, err := IsInternetActiveNetResolver.LookupHost(ctx, testURL)
+	addrs, err := IsInternetActiveNetResolver.LookupIP(ctx, "ip4", testURL)
 
 	// Internet is active (active == true) if both err and ctx.Err() were nil
 	active := err == nil && ctx.Err() == nil

pkg/globalconfig/global_config_test.go

@@ -132,8 +132,8 @@ type internetActiveNetResolverStub struct {
 	err       error
 }
 
-// LookupHost is a custom version of net.LookupHost that wastes some time and then returns
-func (t internetActiveNetResolverStub) LookupHost(ctx context.Context, _ string) ([]string, error) {
+// LookupIP is a custom version of net.LookupIP that wastes some time and then returns
+func (t internetActiveNetResolverStub) LookupIP(ctx context.Context, _, _ string) ([]net.IP, error) {
 	select {
 	case <-time.After(t.sleepTime):
 	case <-ctx.Done():
@@ -150,7 +150,7 @@ func internetActiveResetVariables() {
 	globalconfig.DdevGlobalConfig.InternetDetectionTimeout = nodeps.InternetDetectionTimeoutDefault
 }
 
-// TestIsInternetActiveErrorOccurred tests if IsInternetActive() returns false when LookupHost returns an error
+// TestIsInternetActiveErrorOccurred tests if IsInternetActive() returns false when LookupIP returns an error
 func TestIsInternetActiveErrorOccurred(t *testing.T) {
 	internetActiveResetVariables()
 
@@ -184,8 +184,8 @@ func TestIsInternetActiveAlreadyChecked(t *testing.T) {
 	asrt.True(t, globalconfig.IsInternetActive())
 }
 
-// TestIsInternetActive tests if IsInternetActive() returns true, when the LookupHost call goes well
-// and if it properly sets the globals so it won't execute the LookupHost again.
+// TestIsInternetActive tests if IsInternetActive() returns true, when the LookupIP call goes well
+// and if it properly sets the globals so it won't execute the LookupIP again.
 func TestIsInternetActive(t *testing.T) {
 	internetActiveResetVariables()
 

pkg/netutil/netutil.go

@@ -44,18 +44,20 @@ func IsPortActive(port string) bool {
 	return false
 }
 
-// IsLocalIP returns true if the provided IP address is
+// HasLocalIP returns true if at least one of the provided IP addresses is
 // assigned to the local computer
-func IsLocalIP(ipAddress string) bool {
+func HasLocalIP(ipAddresses []net.IP) bool {
 	dockerIP, err := dockerutil.GetDockerIP()
 
 	if err != nil {
 		util.Warning("Failed to get Docker IP address: %v", err)
 		return false
 	}
 
-	if ipAddress == dockerIP {
-		return true
+	for _, ipAddress := range ipAddresses {
+		if ipAddress.String() == dockerIP {
+			return true
+		}
 	}
 
 	localIPs, err := GetLocalIPs()
@@ -66,10 +68,15 @@ func IsLocalIP(ipAddress string) bool {
 	}
 
 	// Check if the parsed IP address is local using slices.Contains
-	return slices.Contains(localIPs, ipAddress)
+	for _, ipAddress := range ipAddresses {
+		if slices.Contains(localIPs, ipAddress.String()) {
+			return true
+		}
+	}
+	return false
 }
 
-// GetLocalIPs() returns IP addresses associated with the machine
+// GetLocalIPs returns IP addresses associated with the machine
 func GetLocalIPs() ([]string, error) {
 	addrs, err := net.InterfaceAddrs()
 	if err != nil {
@@ -80,12 +87,12 @@ func GetLocalIPs() ([]string, error) {
 	for _, addr := range addrs {
 		switch v := addr.(type) {
 		case *net.IPNet:
-			if v.IP.IsLoopback() {
+			if v.IP.IsLoopback() || v.IP.To4() == nil {
 				continue
 			}
 			localIPs = append(localIPs, v.IP.String())
 		case *net.IPAddr:
-			if v.IP.IsLoopback() {
+			if v.IP.IsLoopback() || v.IP.To4() == nil {
 				continue
 			}
 			localIPs = append(localIPs, v.IP.String())