diff --git a/src/osmo-hnodeb/gtp.c b/src/osmo-hnodeb/gtp.c
index c22de65..ef12cf6 100644
--- a/src/osmo-hnodeb/gtp.c
+++ b/src/osmo-hnodeb/gtp.c
@@ -246,7 +246,7 @@ static int hnb_gtp_wq_read_cb(struct osmo_fd *fd)
 
 	if (hdr->s || hdr->pn || hdr->e)
 		opt_hdr_len = 4;
-	if (hdr->pn)
+	else
 		opt_hdr_len = 0;
 
 	if (msgb_length(msg) < sizeof(*hdr) + opt_hdr_len) {