fix: allow ipv4-mapped ipv6 addresses

Signed-off-by: Steven Kreitzer <[email protected]>

source/source.go

@@ -21,7 +21,7 @@ import (
 	"context"
 	"fmt"
 	"math"
-	"net"
+	"net/netip"
 	"reflect"
 	"strconv"
 	"strings"
@@ -255,12 +255,15 @@ func getTargetsFromTargetAnnotation(annotations map[string]string) endpoint.Targ
 }
 
 // suitableType returns the DNS resource record type suitable for the target.
-// In this case type A for IPs and type CNAME for everything else.
+// In this case type A or AAAA for IPs and type CNAME for everything else.
 func suitableType(target string) string {
-	if net.ParseIP(target) != nil && net.ParseIP(target).To4() != nil {
-		return endpoint.RecordTypeA
-	} else if net.ParseIP(target) != nil && net.ParseIP(target).To16() != nil {
-		return endpoint.RecordTypeAAAA
+	netIP, err := netip.ParseAddr(target)
+	if err == nil {
+		if netIP.Is4() {
+			return endpoint.RecordTypeA
+		} else if netIP.Is6() {
+			return endpoint.RecordTypeAAAA
+		}
 	}
 	return endpoint.RecordTypeCNAME
 }
@@ -276,14 +279,8 @@ func endpointsForHostname(hostname string, targets endpoint.Targets, ttl endpoin
 	for _, t := range targets {
 		switch suitableType(t) {
 		case endpoint.RecordTypeA:
-			if isIPv6String(t) {
-				continue
-			}
 			aTargets = append(aTargets, t)
 		case endpoint.RecordTypeAAAA:
-			if !isIPv6String(t) {
-				continue
-			}
 			aaaaTargets = append(aaaaTargets, t)
 		default:
 			cnameTargets = append(cnameTargets, t)
@@ -387,9 +384,3 @@ func waitForDynamicCacheSync(ctx context.Context, factory dynamicInformerFactory
 	}
 	return nil
 }
-
-// isIPv6String returns if ip is IPv6.
-func isIPv6String(ip string) bool {
-	netIP := net.ParseIP(ip)
-	return netIP != nil && netIP.To4() == nil
-}

source/source_test.go

@@ -85,6 +85,7 @@ func TestSuitableType(t *testing.T) {
 	}{
 		{"8.8.8.8", "", "A"},
 		{"2001:db8::1", "", "AAAA"},
+		{"::ffff:c0a8:101", "", "AAAA"},
 		{"foo.example.org", "", "CNAME"},
 		{"bar.eu-central-1.elb.amazonaws.com", "", "CNAME"},
 	} {