diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index d2a016ef5c41..35d7c887a5b9 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -39,6 +39,7 @@ enum {
 	ND_OPT_DNSSL = 31,		/* RFC6106 */
 	ND_OPT_6CO = 34,		/* RFC6775 */
 	ND_OPT_CAPTIVE_PORTAL = 37,	/* RFC7710 */
+	ND_OPT_PREF64 = 38,		/* RFC-ietf-6man-ra-pref64-09 */
 	__ND_OPT_MAX
 };
 
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 381708112f7d..2241c5f52394 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -197,6 +197,7 @@ static inline int ndisc_is_useropt(const struct net_device *dev,
 	return opt->nd_opt_type == ND_OPT_RDNSS ||
 		opt->nd_opt_type == ND_OPT_DNSSL ||
 		opt->nd_opt_type == ND_OPT_CAPTIVE_PORTAL ||
+		opt->nd_opt_type == ND_OPT_PREF64 ||
 		ndisc_ops_is_useropt(dev, opt->nd_opt_type);
 }