diff --git a/gtests/net/packetdrill/packet_parser.c b/gtests/net/packetdrill/packet_parser.c
index 1b4d631d368d2efff3e8f153c0a904322e52a6ce..0c95a70284e219ecf9e1f4056e19705377d29f5f 100644
--- a/gtests/net/packetdrill/packet_parser.c
+++ b/gtests/net/packetdrill/packet_parser.c
@@ -570,7 +570,7 @@ error_out:
 	return PACKET_BAD;
 }
 
-int parse_mpls(struct packet *packet, u8 *header_start, u8 *packet_end,
+static int parse_mpls(struct packet *packet, u8 *header_start, u8 *packet_end,
 		      char **error)
 {
 	struct header *mpls_header = NULL;