gsm0808: Add a method to create a new DTAP message with a msgb

2 files changed, 24 insertions, 0 deletions

diff --git a/include/osmocore/gsm0808.h b/include/osmocore/gsm0808.h
index 39a439b2..c6d11e10 100644
--- a/include/osmocore/gsm0808.h
+++ b/include/osmocore/gsm0808.h
@@ -37,6 +37,7 @@ struct msgb *gsm0808_create_assignment_completed(uint8_t rr_cause,
 						 uint8_t speech_mode);
 struct msgb *gsm0808_create_assignment_failure(uint8_t cause, uint8_t *rr_cause);
 
+struct msgb *gsm0808_create_dtap(struct msgb *msg, uint8_t link_id);
 void gsm0808_prepend_dtap_header(struct msgb *msg, uint8_t link_id);
 
 const struct tlv_definition *gsm0808_att_tlvdef();
diff --git a/src/gsm0808.c b/src/gsm0808.c
index 3962baaf..7c9fa091 100644
--- a/src/gsm0808.c
+++ b/src/gsm0808.c
@@ -292,6 +292,29 @@ void gsm0808_prepend_dtap_header(struct msgb *msg, uint8_t link_id)
 	hh[2] = msg->len - 3;
 }
 
+struct msgb *gsm0808_create_dtap(struct msgb *msg_l3, uint8_t link_id)
+{
+	struct dtap_header *header;
+	uint8_t *data;
+	struct msgb *msg = msgb_alloc_headroom(BSSMAP_MSG_SIZE, BSSMAP_MSG_HEADROOM,
+					       "dtap");
+	if (!msg)
+		return NULL;
+
+	/* DTAP header */
+	msg->l3h = msgb_put(msg, sizeof(*header));
+	header = (struct dtap_header *) &msg->l3h[0];
+	header->type = BSSAP_MSG_DTAP;
+	header->link_id = link_id;
+	header->length = msgb_l3len(msg_l3);
+
+	/* Payload */
+	data = msgb_put(msg, header->length);
+	memcpy(data, msg_l3->l3h, header->length);
+
+	return msg;
+}
+
 static const struct tlv_definition bss_att_tlvdef = {
 	.def = {
 		[GSM0808_IE_IMSI]		    = { TLV_TYPE_TLV },