ranap_common_ran: add decoder for CN/MSC originated messages

Lets add a counterpart for ranap_common_cn that works the same, but
decodes CN/MSC originated messages.

Change-Id: Iad4c2743d4d1ddf8ad49002d1fe6866f22eb9e98
Related: OS#5152

include/osmocom/ranap/Makefile.am

@@ -10,6 +10,7 @@ ranap_HEADERS = \
 	ranap_ies_defs.h \
 	ranap_common.h \
 	ranap_common_cn.h \
+	ranap_common_ran.h \
 	ranap_msg_factory.h \
 	iu_helpers.h \
 	iu_client.h \

include/osmocom/ranap/ranap_common.h

@@ -596,6 +596,9 @@ struct gprs_ra_id;
 extern int _ranap_DRANAP;
 #define RANAP_DEBUG(x, args ...) DEBUGP(_ranap_DRANAP, x, ## args)
 
+/* Callback to be used with decoder functions in ranap_common_cn.c  ranap_common_ran.c */
+typedef void (*ranap_handle_cb)(void *ctx, ranap_message *ranap_msg);
+
 extern int asn1_xer_print;
 
 extern const struct value_string ranap_presence_vals[5];

include/osmocom/ranap/ranap_common_cn.h

@@ -5,8 +5,6 @@
 #include <osmocom/ranap/ranap_common.h>
 #include <osmocom/ranap/ranap_ies_defs.h>
 
-typedef void (*ranap_handle_cb)(void *ctx, ranap_message *ranap_msg);
-
 /* free a decoded connection-less RANAP message */
 void ranap_cn_rx_cl_free(ranap_message *message);
 

include/osmocom/ranap/ranap_common_ran.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <stdint.h>
+
+#include <osmocom/ranap/ranap_common.h>
+#include <osmocom/ranap/ranap_ies_defs.h>
+
+/* free a decoded connection-oriented RANAP message */
+void ranap_ran_rx_co_free(ranap_message *message);
+
+/* decode a connection-oriented RANAP message */
+int ranap_ran_rx_co_decode(void *ctx, ranap_message *message, uint8_t *data, size_t len);
+
+/* receive a connection-oriented RANAP message */
+int ranap_ran_rx_co(ranap_handle_cb cb, void *ctx, uint8_t *data, size_t len);

src/Makefile.am

@@ -75,7 +75,7 @@ libosmo_ranap_la_LDFLAGS = $(AM_LDFLAGS) -version-info $(RANAP_LIBVERSION)
 libosmo_ranap_la_LIBADD = $(OSMOCORE_LIBS) $(OSMOGSM_LIBS) $(OSMOVTY_LIBS) $(OSMOSIGTRAN_LIBS) \
 			  $(ASN1C_LIBS) ranap/libosmo-asn1-ranap.la
 libosmo_ranap_la_SOURCES = ranap_common.c ranap_encoder.c ranap_decoder.c ranap_msg_factory.c iu_helpers.c \
-			   ranap_common_cn.c iu_client.c iu_client_vty.c
+			   ranap_common_cn.c ranap_common_ran.c iu_client.c iu_client_vty.c
 
 libosmo_rua_la_LDFLAGS = $(AM_LDFLAGS) -version-info $(HNBAP_LIBVERSION)
 libosmo_rua_la_LIBADD = $(OSMOCORE_LIBS) $(OSMOGSM_LIBS) $(OSMOVTY_LIBS) $(OSMOSIGTRAN_LIBS) \

src/ranap_common_ran.c

@@ -0,0 +1,184 @@
+/* RANAP interface for a ran-network node */
+
+/* (C) 2021 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#include <osmocom/core/utils.h>
+#include <osmocom/core/logging.h>
+
+#include <osmocom/ranap/ranap_common.h>
+#include <osmocom/ranap/ranap_common_ran.h>
+#include <osmocom/ranap/ranap_ies_defs.h>
+
+#define DRANAP _ranap_DRANAP
+
+static int ran_ranap_rx_initiating_msg_co(void *ctx, RANAP_InitiatingMessage_t *imsg, ranap_message *message)
+{
+	int rc = 0;
+
+	message->procedureCode = imsg->procedureCode;
+	message->criticality = imsg->criticality;
+
+	DEBUGP(DRANAP, "Rx CO IM (%s)\n", get_value_string(ranap_procedure_code_vals, imsg->procedureCode));
+
+	switch (imsg->procedureCode) {
+	case RANAP_ProcedureCode_id_RAB_Assignment:
+		rc = ranap_decode_rab_assignmentrequesties(&message->msg.raB_AssignmentRequestIEs, &imsg->value);
+		break;
+	case RANAP_ProcedureCode_id_Iu_Release:
+		rc = ranap_decode_iu_releasecommandies(&message->msg.iu_ReleaseCommandIEs, &imsg->value);
+		break;
+	default:
+		LOGP(DRANAP, LOGL_NOTICE, "Received suspicious RANAP Procedure %s (CO, IM) from CN, ignoring\n",
+		     get_value_string(ranap_procedure_code_vals, imsg->procedureCode));
+		rc = -1;
+		break;
+	}
+
+	return rc;
+}
+
+static void ran_ranap_free_initiating_msg_co(ranap_message *message)
+{
+	switch (message->procedureCode) {
+	case RANAP_ProcedureCode_id_RAB_Assignment:
+		ranap_free_rab_assignmentrequesties(&message->msg.raB_AssignmentRequestIEs);
+		break;
+	case RANAP_ProcedureCode_id_Iu_Release:
+		ranap_free_iu_releasecommandies(&message->msg.iu_ReleaseCommandIEs);
+		break;
+	default:
+		LOGP(DRANAP, LOGL_NOTICE, "Not freeing suspicious RANAP "
+		     "Procedure %s (CO, IM) from CN\n",
+		     get_value_string(ranap_procedure_code_vals, message->procedureCode));
+		break;
+	}
+}
+
+static int _ran_ranap_rx_co(void *ctx, RANAP_RANAP_PDU_t *pdu, ranap_message *message)
+{
+	int rc = 0;
+
+	switch (pdu->present) {
+	case RANAP_RANAP_PDU_PR_initiatingMessage:
+		rc = ran_ranap_rx_initiating_msg_co(ctx, &pdu->choice.initiatingMessage, message);
+		break;
+	case RANAP_RANAP_PDU_PR_successfulOutcome:
+		LOGP(DRANAP, LOGL_NOTICE, "Received unsupported RANAP "
+		     "successful outcome procedure %s (CO) from CN, ignoring\n",
+		     get_value_string(ranap_procedure_code_vals, pdu->choice.successfulOutcome.procedureCode));
+		rc = -1;
+		break;
+	case RANAP_RANAP_PDU_PR_unsuccessfulOutcome:
+		LOGP(DRANAP, LOGL_NOTICE, "Received unsupported RANAP "
+		     "unsuccessful outcome procedure %s (CO) from CN, ignoring\n",
+		     get_value_string(ranap_procedure_code_vals, pdu->choice.unsuccessfulOutcome.procedureCode));
+		rc = -1;
+		break;
+	case RANAP_RANAP_PDU_PR_outcome:
+		LOGP(DRANAP, LOGL_NOTICE, "Received unsupported RANAP "
+		     "outcome procedure %s (CO) from CN, ignoring\n",
+		     get_value_string(ranap_procedure_code_vals, pdu->choice.outcome.procedureCode));
+		rc = -1;
+		break;
+	default:
+		LOGP(DRANAP, LOGL_NOTICE, "Received suspicious RANAP "
+		     "presence %s (CO) from CN, ignoring\n", get_value_string(ranap_presence_vals, pdu->present));
+		rc = -1;
+		break;
+	}
+
+	return rc;
+}
+
+/* free a decoded connection-oriented RANAP message */
+void ranap_ran_rx_co_free(ranap_message *message)
+{
+	switch (message->direction) {
+	case RANAP_RANAP_PDU_PR_initiatingMessage:
+		ran_ranap_free_initiating_msg_co(message);
+		break;
+	case RANAP_RANAP_PDU_PR_successfulOutcome:
+		LOGP(DRANAP, LOGL_NOTICE, "Not freeing unsupported RANAP "
+		     "successful outcome procedure (CO) from CN\n");
+		break;
+	case RANAP_RANAP_PDU_PR_unsuccessfulOutcome:
+		LOGP(DRANAP, LOGL_NOTICE, "Not freeing unsupported RANAP "
+		     "unsuccessful outcome procedure (CO) from CN\n");
+		break;
+	case RANAP_RANAP_PDU_PR_outcome:
+		LOGP(DRANAP, LOGL_NOTICE, "Not freeing unsupported RANAP "
+		     "outcome procedure (CO) from CN\n");
+		break;
+	default:
+		LOGP(DRANAP, LOGL_NOTICE, "Received suspicious RANAP "
+		     "presence %s (CO) from CN, ignoring\n",
+		     get_value_string(ranap_presence_vals, message->direction));
+		break;
+	}
+}
+
+/* decode a connection-oriented RANAP message */
+int ranap_ran_rx_co_decode(void *ctx, ranap_message *message, uint8_t *data, size_t len)
+{
+	RANAP_RANAP_PDU_t *pdu = NULL;
+	asn_dec_rval_t dec_ret;
+	int rc;
+
+	memset(message, 0, sizeof(*message));
+
+	dec_ret = aper_decode(NULL, &asn_DEF_RANAP_RANAP_PDU, (void **)&pdu, data, len, 0, 0);
+	if (dec_ret.code != RC_OK) {
+		LOGP(DRANAP, LOGL_ERROR, "Error in RANAP ASN.1 decode\n");
+		return -1;
+	}
+
+	message->direction = pdu->present;
+
+	rc = _ran_ranap_rx_co(ctx, pdu, message);
+
+	ASN_STRUCT_FREE(asn_DEF_RANAP_RANAP_PDU, pdu);
+
+	return rc;
+}
+
+/* receive a connection-oriented RANAP message and call
+ * cn_ranap_handle_co() with the resulting ranap_message struct */
+int ranap_ran_rx_co(ranap_handle_cb cb, void *ctx, uint8_t *data, size_t len)
+{
+	ranap_message message;
+	int rc;
+
+	rc = ranap_ran_rx_co_decode(ctx, &message, data, len);
+
+	if (rc == 0)
+		(*cb) (ctx, &message);
+	else
+		LOGP(DRANAP, LOGL_ERROR, "Not calling ran_ranap_handle_co() due to rc=%d\n", rc);
+
+	/* Free the asn1 structs in message */
+	ranap_ran_rx_co_free(&message);
+
+	return rc;
+}