diff --git a/ip/ipxfrm.c b/ip/ipxfrm.c
index cce5151..05e4098 100644
--- a/ip/ipxfrm.c
+++ b/ip/ipxfrm.c
@@ -1280,6 +1281,7 @@ static int xfrm_selector_upspec_parse(struct xfrm_selector *sel,
 		missarg("UPSPEC");
 	if (sportp || dportp) {
 		switch (sel->proto) {
+		case IPPROTO_IP:
 		case IPPROTO_TCP:
 		case IPPROTO_UDP:
 		case IPPROTO_SCTP: