sbcap: Send Error Indication if decoding rx msg fails

Change-Id: I444290f3d697e7485e04eaa38acd8fc3623e0eab

include/osmocom/cbc/sbcap_msg.h

@@ -1,6 +1,7 @@
 #pragma once
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/netif/stream.h>
+#include <osmocom/sbcap/sbcap_common.h>
 
 #include "cbc_data.h"
 
@@ -9,3 +10,4 @@ typedef struct SBcAP_SBC_AP_PDU SBcAP_SBC_AP_PDU_t;
 
 SBcAP_SBC_AP_PDU_t *sbcap_gen_write_replace_warning_req(void *ctx, const struct cbc_message *cbcmsg);
 SBcAP_SBC_AP_PDU_t *sbcap_gen_stop_warning_req(void *ctx, const struct cbc_message *cbcmsg);
+SBcAP_SBC_AP_PDU_t *sbcap_gen_error_ind(void *ctx, SBcAP_Cause_t cause, SBcAP_SBC_AP_PDU_t *rx_pdu);

include/osmocom/sbcap/sbcap_common.h

@@ -141,8 +141,14 @@ const char *sbcap_cause_str(SBcAP_Cause_t cause);
 
 void sbcap_set_log_area(int log_area);
 
+SBcAP_ProcedureCode_t sbcap_pdu_get_procedure_code(const SBcAP_SBC_AP_PDU_t *pdu);
+SBcAP_Criticality_t sbcap_pdu_get_criticality(const SBcAP_SBC_AP_PDU_t *pdu);
+
 SBcAP_Write_Replace_Warning_Request_IEs_t *sbcap_alloc_Write_Replace_Warning_Request_IE(
 	long id, SBcAP_Criticality_t criticality, SBcAP_Write_Replace_Warning_Request_IEs__value_PR present);
 
 SBcAP_Stop_Warning_Request_IEs_t *sbcap_alloc_Stop_Warning_Request_IE(
 	long id, SBcAP_Criticality_t criticality, SBcAP_Stop_Warning_Request_IEs__value_PR present);
+
+SBcAP_ErrorIndicationIEs_t *sbcap_alloc_Error_Indication_IE(
+	long id, SBcAP_Criticality_t criticality, SBcAP_Stop_Warning_Request_IEs__value_PR present);

src/sbcap/sbcap_common.c

@@ -111,6 +111,36 @@ void sbcap_pdu_free(SBcAP_SBC_AP_PDU_t *pdu)
 	ASN_STRUCT_FREE(asn_DEF_SBcAP_SBC_AP_PDU, pdu);
 }
 
+SBcAP_ProcedureCode_t sbcap_pdu_get_procedure_code(const SBcAP_SBC_AP_PDU_t *pdu)
+{
+	switch (pdu->present) {
+	case SBcAP_SBC_AP_PDU_PR_initiatingMessage:
+		return pdu->choice.initiatingMessage.procedureCode;
+	case SBcAP_SBC_AP_PDU_PR_successfulOutcome:
+		return pdu->choice.successfulOutcome.procedureCode;
+	case SBcAP_SBC_AP_PDU_PR_unsuccessfulOutcome:
+		return pdu->choice.unsuccessfulOutcome.procedureCode;
+	case SBcAP_SBC_AP_PDU_PR_NOTHING:
+	default:
+		return -1;
+	}
+}
+
+SBcAP_Criticality_t sbcap_pdu_get_criticality(const SBcAP_SBC_AP_PDU_t *pdu)
+{
+	switch (pdu->present) {
+	case SBcAP_SBC_AP_PDU_PR_initiatingMessage:
+		return pdu->choice.initiatingMessage.criticality;
+	case SBcAP_SBC_AP_PDU_PR_successfulOutcome:
+		return pdu->choice.successfulOutcome.criticality;
+	case SBcAP_SBC_AP_PDU_PR_unsuccessfulOutcome:
+		return pdu->choice.unsuccessfulOutcome.criticality;
+	case SBcAP_SBC_AP_PDU_PR_NOTHING:
+	default:
+		return -1;
+	}
+}
+
 void sbcap_set_log_area(int log_area)
 {
 	_sbcap_DSBCAP = log_area;
@@ -135,3 +165,13 @@ SBcAP_Stop_Warning_Request_IEs_t *sbcap_alloc_Stop_Warning_Request_IE(
 	ie->value.present = present;
 	return ie;
 }
+
+SBcAP_ErrorIndicationIEs_t *sbcap_alloc_Error_Indication_IE(
+	long id, SBcAP_Criticality_t criticality, SBcAP_Stop_Warning_Request_IEs__value_PR present)
+{
+	SBcAP_ErrorIndicationIEs_t *ie = CALLOC(1, sizeof(*ie));
+	ie->id = id;
+	ie->criticality = criticality;
+	ie->value.present = present;
+	return ie;
+}

src/sbcap_link.c

@@ -39,6 +39,7 @@
 #include <osmocom/cbc/cbc_data.h>
 #include <osmocom/cbc/sbcap_link.h>
 #include <osmocom/cbc/sbcap_link_fsm.h>
+#include <osmocom/cbc/sbcap_msg.h>
 #include <osmocom/cbc/cbc_peer.h>
 #include <osmocom/cbc/debug.h>
 
@@ -166,6 +167,13 @@ static int cbc_sbcap_link_cli_read_cb(struct osmo_stream_cli *conn)
 		g_cbc->sbcap.mgr->rx_cb(link, pdu);
 	} else {
 		LOGPSBCAPC(link, LOGL_ERROR, "Unable to decode %s\n", msgb_hexdump(msg));
+		pdu = sbcap_gen_error_ind(link, SBcAP_Cause_unrecognised_message, NULL);
+		if (pdu) {
+			cbc_sbcap_link_tx(link, pdu);
+		} else {
+			LOGPSBCAPC(link, LOGL_ERROR,
+				   "Tx SBc-AP Error-Indication: msg gen failed\n");
+		}
 	}
 out:
 	msgb_free(msg);

src/sbcap_msg.c

@@ -291,3 +291,48 @@ SBcAP_SBC_AP_PDU_t *sbcap_gen_stop_warning_req(void *ctx, const struct cbc_messa
 
 	return pdu;
 }
+
+/* generate a SBc-AP ERROR INDICATION, 3GPP TS 29.168 4.3.4.2A.1.
+ * rx_pdu can be NULL.
+ */
+SBcAP_SBC_AP_PDU_t *sbcap_gen_error_ind(void *ctx, SBcAP_Cause_t cause, SBcAP_SBC_AP_PDU_t *rx_pdu)
+{
+	SBcAP_SBC_AP_PDU_t *pdu;
+	SBcAP_ErrorIndicationIEs_t *ie;
+
+	pdu = sbcap_pdu_alloc();
+	if (!pdu)
+		return NULL;
+	pdu->present = SBcAP_SBC_AP_PDU_PR_initiatingMessage;
+	pdu->choice.initiatingMessage.procedureCode = SBcAP_ProcedureId_Error_Indication;
+	pdu->choice.initiatingMessage.criticality = SBcAP_Criticality_ignore;
+	pdu->choice.initiatingMessage.value.present = SBcAP_InitiatingMessage__value_PR_Error_Indication;
+
+	A_SEQUENCE_OF(void) *as_pdu = (void *)&pdu->choice.initiatingMessage.value.choice.Error_Indication.protocolIEs.list;
+
+	/* Cause, Optional:
+	 * 3GPP TS 36.413 4.3.4.3.2
+	 * static const long asn_VAL_19_SBcAP_id_Cause = 1; */
+	ie = sbcap_alloc_Error_Indication_IE(1, SBcAP_Criticality_ignore,
+		SBcAP_ErrorIndicationIEs__value_PR_Cause);
+	ie->value.choice.Cause = cause;
+	ASN_SEQUENCE_ADD(as_pdu, ie);
+
+	if (rx_pdu) {
+		SBcAP_Criticality_Diagnostics_t *diag_ie;
+		/* Criticality Diagnostics, Optional:
+		 * 3GPP TS 36.413 4.3.4.3.3
+		 * static const long asn_VAL_20_SBcAP_id_Criticality_Diagnostics = 2; */
+		ie = sbcap_alloc_Error_Indication_IE(1, SBcAP_Criticality_ignore,
+			SBcAP_ErrorIndicationIEs__value_PR_Criticality_Diagnostics);
+		diag_ie = &ie->value.choice.Criticality_Diagnostics;
+		diag_ie->procedureCode = MALLOC(sizeof(*diag_ie->procedureCode));
+		*diag_ie->procedureCode = sbcap_pdu_get_procedure_code(rx_pdu);
+		diag_ie->triggeringMessage = MALLOC(sizeof(*diag_ie->triggeringMessage));
+		*diag_ie->triggeringMessage = rx_pdu->present;
+		diag_ie->procedureCriticality = MALLOC(sizeof(*diag_ie->procedureCriticality));
+		*diag_ie->procedureCriticality = sbcap_pdu_get_criticality(rx_pdu);
+		ASN_SEQUENCE_ADD(as_pdu, ie);
+	}
+	return pdu;
+}