Flush using AF_UNSPEC and netfilter package

internal/netlink/conntrack_linux.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/mdlayher/netlink"
 	"github.com/ti-mo/netfilter"
+	"golang.org/x/sys/unix"
 )
 
 func (n *NetLink) FlushConntrack() error {
@@ -14,25 +15,21 @@ func (n *NetLink) FlushConntrack() error {
 	}
 	defer conn.Close()
 
-	families := [...]netfilter.ProtoFamily{netfilter.ProtoIPv4, netfilter.ProtoIPv6}
-	for _, family := range families {
-		const IPCtnlMsgCtDelete = 2
-		request, err := netfilter.MarshalNetlink(
-			netfilter.Header{
-				SubsystemID: netfilter.NFSubsysCTNetlink,
-				MessageType: netfilter.MessageType(IPCtnlMsgCtDelete),
-				Family:      family,
-				Flags:       netlink.Request | netlink.Acknowledge,
-			},
-			nil)
-		if err != nil {
-			return fmt.Errorf("encoding netlink request: %w", err)
-		}
+	const ipCtnlMsgCtDelete = netfilter.MessageType(2)
+	header := netfilter.Header{
+		SubsystemID: netfilter.NFSubsysCTNetlink,
+		MessageType: ipCtnlMsgCtDelete,
+		Family:      unix.AF_UNSPEC,
+		Flags:       netlink.Request | netlink.Acknowledge,
+	}
+	request, err := netfilter.MarshalNetlink(header, nil)
+	if err != nil {
+		return fmt.Errorf("encoding netlink request: %w", err)
+	}
 
-		_, err = conn.Query(request)
-		if err != nil {
-			return fmt.Errorf("querying netlink request: %w", err)
-		}
+	_, err = conn.Query(request)
+	if err != nil {
+		return fmt.Errorf("querying netlink request: %w", err)
 	}
 	return nil
 }