gsm0808: Add API to wrap a GSM48 msg with a BSSMAP/DTAP msg.

2 files changed, 10 insertions, 0 deletions

diff --git a/include/osmocore/gsm0808.h b/include/osmocore/gsm0808.h
index a40713f7..9166e54f 100644
--- a/include/osmocore/gsm0808.h
+++ b/include/osmocore/gsm0808.h
@@ -36,6 +36,8 @@ struct msgb *gsm0808_create_assignment_completed(struct gsm_lchan *lchan, uint8_
 						 uint8_t speech_mode);
 struct msgb *gsm0808_create_assignment_failure(uint8_t cause, uint8_t *rr_cause);
 
+void gsm0808_prepend_dtap_header(struct msgb *msg, uint8_t link_id);
+
 const struct tlv_definition *gsm0808_att_tlvdef();
 
 #endif
diff --git a/src/gsm0808.c b/src/gsm0808.c
index 114ddbf6..1dc035b3 100644
--- a/src/gsm0808.c
+++ b/src/gsm0808.c
@@ -266,6 +266,14 @@ struct msgb *gsm0808_create_assignment_failure(uint8_t cause, uint8_t *rr_cause)
 	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 },