diff --git a/route/address.go b/route/address.go
index 5443d67223..9aa2ee113d 100644
--- a/route/address.go
+++ b/route/address.go
@@ -172,7 +172,8 @@ func (a *Inet6Addr) marshal(b []byte) (int, error) {
 func parseInetAddr(af int, b []byte) (Addr, error) {
 	switch af {
 	case syscall.AF_INET:
-		if len(b) < sizeofSockaddrInet {
+		l := int(b[0])
+		if len(b) < l {
 			return nil, errInvalidAddr
 		}
 		a := &Inet4Addr{}