diff --git a/src/gsm0808.c b/src/gsm0808.c
index 114ddbf..1dc035b 100644
--- a/src/gsm0808.c
+++ b/src/gsm0808.c
@@ -266,6 +266,14 @@
 	return msg;
 }
 
+void gsm0808_prepend_dtap_header(struct msgb *msg, uint8_t link_id)
+{
+	uint8_t *hh = msgb_push(msg, 3);
+	hh[0] = BSSAP_MSG_DTAP;
+	hh[1] = link_id;
+	hh[2] = msg->len - 3;
+}
+
 static const struct tlv_definition bss_att_tlvdef = {
 	.def = {
 		[GSM0808_IE_IMSI]		    = { TLV_TYPE_TLV },