bssap: Handle BSSMAP CONFUSION message.

We decode the mesage and print it to the log files at ERROR log level.
We also count it in the BSSMAP message counters. There is not much
else we could do about it.

Depends: If8afd2d096fb66c6c2f255a08fc1129de3d09cec (libosmocore)
Change-Id: Ib4cd94f185f751b2384842222678ff671ac413c4

2 files changed, 55 insertions, 0 deletions

diff --git a/src/osmo-bsc/osmo_bsc_bssap.c b/src/osmo-bsc/osmo_bsc_bssap.c
index ddebb6a7d..388ad14fc 100644
--- a/src/osmo-bsc/osmo_bsc_bssap.c
+++ b/src/osmo-bsc/osmo_bsc_bssap.c
@@ -1006,6 +1006,56 @@ reject:
 	return -EINVAL;
 }
 
+/* Handle Confusion message, MSC indicating an error to us:
+ *
+ * See 3GPP TS 48.008 §3.2.1.45
+ */
+static int bssmap_handle_confusion(struct gsm_subscriber_connection *conn,
+				      struct msgb *msg, unsigned int length)
+{
+	struct tlv_parsed tp;
+	int diag_len;
+	enum gsm0808_cause cause;
+	enum gsm0808_cause_class cause_class;
+	struct gsm0808_diagnostics *diag;
+
+	osmo_bssap_tlv_parse(&tp, msg->l4h + 1, length - 1);
+
+	/* Check for the Cause and Diagnostic mandatory elements */
+	if (!TLVP_PRESENT(&tp, GSM0808_IE_CAUSE) || !TLVP_PRESENT(&tp, GSM0808_IE_DIAGNOSTIC)) {
+		LOGPFSML(conn->fi, LOGL_ERROR,
+		         "Received BSSMAP Confusion message,"
+		         " but either Cause or Diagnostic mandatory IE is not present: %s\n",
+		         osmo_hexdump(msg->l4h, length));
+		return -EINVAL;
+	}
+
+	diag_len = TLVP_LEN(&tp, GSM0808_IE_DIAGNOSTIC);
+	if (diag_len < 5) {
+		LOGPFSML(conn->fi, LOGL_ERROR,
+		         "Received BSSMAP Confusion message with short Diagnostic length: %d (expected > 5)\n",
+		         diag_len);
+		return -EINVAL;
+	}
+
+	cause = gsm0808_get_cause(&tp);
+	cause_class = gsm0808_cause_class(cause);
+	diag = (struct gsm0808_diagnostics *)TLVP_VAL(&tp, GSM0808_IE_DIAGNOSTIC);
+
+	LOGPFSML(conn->fi, LOGL_ERROR,
+	         "Received BSSMAP Confusion: class 0x%x (%s), cause 0x%x (%s), "
+	         "error octet %d (%s), error bit %d (%s), original message: %s\n",
+	         cause_class, gsm0808_cause_class_name(cause_class),
+	         cause, gsm0808_cause_name(cause),
+	         diag->error_pointer_octet,
+	         gsm0808_diagnostics_octet_location_str(diag->error_pointer_octet),
+	         diag->error_pointer_bit,
+	         gsm0808_diagnostics_bit_location_str(diag->error_pointer_bit),
+	         osmo_hexdump(diag->msg, diag_len-2));
+
+	return 0;
+}
+
 static int bssmap_rcvmsg_udt(struct bsc_msc_data *msc,
 			     struct msgb *msg, unsigned int length)
 {
@@ -1082,6 +1132,10 @@ static int bssmap_rcvmsg_dt1(struct gsm_subscriber_connection *conn,
 		rate_ctr_inc(&ctrs[MSC_CTR_BSSMAP_RX_DT1_CLASSMARK_RQST]);
 		ret = gsm48_send_rr_classmark_enquiry(conn->lchan);
 		break;
+	case BSS_MAP_MSG_CONFUSION:
+		rate_ctr_inc(&ctrs[MSC_CTR_BSSMAP_RX_DT1_CONFUSION]);
+		ret = bssmap_handle_confusion(conn, msg, length);
+		break;
 	default:
 		rate_ctr_inc(&ctrs[MSC_CTR_BSSMAP_RX_DT1_UNKNOWN]);
 		LOGP(DMSC, LOGL_NOTICE, "Unimplemented msg type: %s\n",
diff --git a/src/osmo-bsc/osmo_bsc_msc.c b/src/osmo-bsc/osmo_bsc_msc.c
index db3ffe4e7..e58ff7faf 100644
--- a/src/osmo-bsc/osmo_bsc_msc.c
+++ b/src/osmo-bsc/osmo_bsc_msc.c
@@ -55,6 +55,7 @@ static const struct rate_ctr_desc msc_ctr_description[] = {
 	[MSC_CTR_BSSMAP_RX_DT1_LCLS_CONNECT_CTRL] = {"bssmap:rx:dt1:lcls_connect_ctrl:cmd", "Number of received BSSMAP DT1 LCLS CONNECT CTRL messages"},
 	[MSC_CTR_BSSMAP_RX_DT1_HANDOVER_CMD] =      {"bssmap:rx:dt1:handover:cmd", "Number of received BSSMAP DT1 HANDOVER CMD messages"},
 	[MSC_CTR_BSSMAP_RX_DT1_CLASSMARK_RQST] =    {"bssmap:rx:dt1:classmark:rqst", "Number of received BSSMAP DT1 CLASSMARK RQST messages"},
+	[MSC_CTR_BSSMAP_RX_DT1_CONFUSION] =         {"bssmap:rx:dt1:confusion", "Number of received BSSMAP DT1 CONFUSION messages"},
 	[MSC_CTR_BSSMAP_RX_DT1_UNKNOWN] =           {"bssmap:rx:dt1:err_unknown", "Number of received BSSMAP unknown DT1 messages"},
 	[MSC_CTR_BSSMAP_RX_DT1_DTAP] =              {"bssmap:rx:dt1:dtap:good", "Number of received BSSMAP DTAP messages"},
 	[MSC_CTR_BSSMAP_RX_DT1_DTAP_ERROR] =        {"bssmap:rx:dt1:dtap:error", "Number of received BSSMAP DTAP messages with errors"},