log: log the sccp message type of messages sent

We already log the message type of sccp messages we receive, but
for transmitting the log output is missing.

Also log the message type for tramsitted sccp messages.

Change-Id: I6736f15ddc03e5f70c3504abffbae6cbf766c9d7
diff --git a/src/osmo-bsc/osmo_bsc_sigtran.c b/src/osmo-bsc/osmo_bsc_sigtran.c
index 48796c1..31a8cea 100644
--- a/src/osmo-bsc/osmo_bsc_sigtran.c
+++ b/src/osmo-bsc/osmo_bsc_sigtran.c
@@ -331,6 +331,22 @@
 
 	msc = conn->msc;
 
+	/* Log the type of the message we are sending. This is just
+	 * informative, do not stop if detecting the type fails */
+	if (msg->len >= 3) {
+		switch (msg->data[0]) {
+		case BSSAP_MSG_BSS_MANAGEMENT:
+			LOGP(DMSC, LOGL_INFO, "Tx MSC %s\n", gsm0808_bssmap_name(msg->data[2]));
+			break;
+		case BSSAP_MSG_DTAP:
+			LOGP(DMSC, LOGL_INFO, "Tx MSC DTAP\n");
+			break;
+		default:
+			LOGP(DMSC, LOGL_ERROR, "Tx MSC (unknwon message type)\n");
+		}
+	} else
+		LOGP(DMSC, LOGL_ERROR, "Tx MSC (message too short)\n");
+
 	if (a_reset_conn_ready(msc->a.reset) == false) {
 		LOGP(DMSC, LOGL_ERROR, "MSC is not connected. Dropping.\n");
 		return -EINVAL;