[bssap] First go at implementing ASSIGNMENT REQUEST

4 files changed, 401 insertions, 6 deletions

diff --git a/openbsc/include/openbsc/bssap.h b/openbsc/include/openbsc/bssap.h
index d6553409a..809cbfd7d 100644
--- a/openbsc/include/openbsc/bssap.h
+++ b/openbsc/include/openbsc/bssap.h
@@ -157,9 +157,9 @@ enum GSM0808_IE_CODING {
 	GSM0808_IE_RESERVED_1			= 15,
 	GSM0808_IE_RESERVED_2			= 16,
 	GSM0808_IE_RESERVED_3			= 17,
-	GSM0808_IE_CLASSMARK_INFORMATION_TYPE_2	= 18,
-	GSM0808_IE_CLASSMARK_INFORMATION_TYPE_3	= 19,
-	GSM0808_IE_INTERFERENCE_BAND_TO_BE_USED	= 20,
+	GSM0808_IE_CLASSMARK_INFORMATION_T2	= 18,
+	GSM0808_IE_CLASSMARK_INFORMATION_T3	= 19,
+	GSM0808_IE_INTERFERENCE_BAND_TO_USE	= 20,
 	GSM0808_IE_RR_CAUSE			= 21,
 	GSM0808_IE_RESERVED_4			= 22,
 	GSM0808_IE_LAYER_3_INFORMATION		= 23,
@@ -196,13 +196,13 @@ enum GSM0808_IE_CODING {
 	GSM0808_IE_CONNECTION_RELEASE_RQSTED	= 54,
 	GSM0808_IE_GROUP_CALL_REFERENCE		= 55,
 	GSM0808_IE_EMLPP_PRIORITY		= 56,
-	GSM0808_IE_CONFIGURATION_EVOLUTION_INDICATION	= 57,
+	GSM0808_IE_CONFIG_EVO_INDI		= 57,
 	GSM0808_IE_OLD_BSS_TO_NEW_BSS_INFORMATION	= 58,
 	GSM0808_IE_LSA_IDENTIFIER		= 59,
 	GSM0808_IE_LSA_IDENTIFIER_LIST		= 60,
 	GSM0808_IE_LSA_INFORMATION		= 61,
 	GSM0808_IE_LCS_QOS			= 62,
-	GSM0808_IE_LSA_ACCESS_CONTROL_SUPPRESSION = 63,
+	GSM0808_IE_LSA_ACCESS_CTRL_SUPPR	= 63,
 	GSM0808_IE_LCS_PRIORITY			= 67,
 	GSM0808_IE_LOCATION_TYPE		= 68,
 	GSM0808_IE_LOCATION_ESTIMATE		= 69,
@@ -274,6 +274,11 @@ struct msgb *bssmap_create_clear_complete(void);
 struct msgb *bssmap_create_cipher_complete(struct msgb *layer3, int bsc_enc_algo);
 struct msgb *bssmap_create_cipher_reject(u_int8_t cause);
 struct msgb *bssmap_create_sapi_reject(u_int8_t link_id);
+struct msgb *bssmap_create_assignment_completed(struct gsm_lchan *lchan, u_int8_t rr_cause);
+struct msgb *bssmap_create_assignment_failure(u_int8_t cause, u_int8_t *rr_cause);
+
+void gsm0808_send_assignment_failure(struct gsm_lchan *l, u_int8_t cause, u_int8_t *rr_value);
+void gsm0808_send_assignment_compl(struct gsm_lchan *l, u_int8_t rr_value);
 
 int dtap_rcvmsg(struct gsm_lchan *lchan, struct msgb *msg, unsigned int length);
 struct msgb *dtap_create_msg(struct msgb *msg_l3, u_int8_t link_id);
diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index d01973e4b..b79722102 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -122,6 +122,15 @@ struct bss_sccp_connection_data {
 	struct sccp_connection *sccp;
 	int ciphering_handled : 1;
 
+        /* Timers... */
+
+        /* for assginment command */
+        struct timer_list T10;
+
+	/* audio handling */
+	int rtp_port;
+	int rtp_payload2;
+
 	/* Queue SCCP and GSM0408 messages */
 	struct llist_head gsm_queue;
 	unsigned int gsm_queue_size;
@@ -130,6 +139,7 @@ struct bss_sccp_connection_data {
 	unsigned int sccp_queue_size;
 };
 
+#define GSM0808_T10_VALUE	6, 0
 #define sccp_get_lchan(data_ctx) ((struct bss_sccp_connection_data *)data_ctx)->lchan
 #define lchan_get_sccp(lchan) lchan->msc_data->sccp
 struct bss_sccp_connection_data *bss_sccp_create_data();
diff --git a/openbsc/src/bsc_msc_ip.c b/openbsc/src/bsc_msc_ip.c
index f3c85904e..27603a7eb 100644
--- a/openbsc/src/bsc_msc_ip.c
+++ b/openbsc/src/bsc_msc_ip.c
@@ -52,6 +52,7 @@ struct gsm_network *bsc_gsmnet = 0;
 static const char *config_file = "openbsc.cfg";
 static char *msc_address = "127.0.0.1";
 static struct bsc_fd msc_connection;
+static struct in_addr local_addr;
 extern int ipacc_rtp_direct;
 
 extern int bsc_bootstrap_network(int (*layer4)(struct gsm_network *, int, void *), const char *cfg_file);
@@ -74,6 +75,7 @@ struct bss_sccp_connection_data *bss_sccp_create_data()
 
 void bss_sccp_free_data(struct bss_sccp_connection_data *data)
 {
+	bsc_del_timer(&data->T10);
 	bsc_free_queued(data->sccp);
 	bts_free_queued(data);
 	talloc_free(data);
@@ -267,6 +269,67 @@ static int handle_cipher_m_complete(struct msgb *msg)
 	return 1;
 }
 
+/* Receive a ASSIGNMENT COMPLETE */
+static int handle_ass_compl(struct msgb *msg)
+{
+	struct gsm48_hdr *gh = msgb_l3(msg);
+
+	DEBUGP(DMSC, "ASSIGNMENT COMPLETE from MS, forwarding to MSC\n");
+
+	if (!msg->lchan->msc_data) {
+		DEBUGP(DMSC, "No MSC data\n");
+		return -1;
+	}
+
+	if (msgb_l3len(msg) - sizeof(*gh) != 1) {
+		DEBUGP(DMSC, "assignment failure invalid: %d\n",
+			msgb_l3len(msg) - sizeof(*gh));
+		return -1;
+	}
+	gsm0808_send_assignment_compl(msg->lchan, gh->data[0]);
+	return 1;
+}
+
+/*
+ * Receive a ASSIGNMENT FAILURE. If the message is failed
+ * to be parsed the T10 timer will send the failure.
+ */
+static int handle_ass_fail(struct msgb *msg)
+{
+	struct gsm48_hdr *gh = msgb_l3(msg);
+
+	DEBUGP(DMSC, "ASSIGNMENT FAILURE from MS, forwarding to MSC\n");
+	if (!msg->lchan->msc_data) {
+		DEBUGP(DMSC, "No MSC data\n");
+		return -1;
+	}
+
+	if (msgb_l3len(msg) - sizeof(*gh) != 1) {
+		DEBUGP(DMSC, "assignment failure invalid: %d\n",
+			msgb_l3len(msg) - sizeof(*gh));
+		return -1;
+	}
+
+	gsm0808_send_assignment_failure(msg->lchan,
+		GSM0808_CAUSE_RADIO_INTERFACE_MESSAGE_FAILURE, &gh->data[0]);
+	return 1;
+}
+
+/*
+ * Receive a GSM04.08 MODIFY ACK. Actually we have to check
+ * the content to see if this was a success or not.
+ */
+static int handle_modify_ack(struct msgb *msg)
+{
+	int rc;
+
+	/* modify RSL */
+	rc = gsm48_rx_rr_modif_ack(msg);
+
+	gsm0808_send_assignment_compl(msg->lchan, 0);
+	return 1;
+}
+
 /* Receive a GSM 04.08 Radio Resource (RR) message */
 static int gsm0408_rcv_rr(struct msgb *msg)
 {
@@ -284,6 +347,15 @@ static int gsm0408_rcv_rr(struct msgb *msg)
 	case GSM48_MT_RR_CIPH_M_COMPL:
 		rc = handle_cipher_m_complete(msg);
 		break;
+	case GSM48_MT_RR_ASS_COMPL:
+		rc = handle_ass_compl(msg);
+		break;
+	case GSM48_MT_RR_ASS_FAIL:
+		rc = handle_ass_fail(msg);
+		break;
+	case GSM48_MT_RR_CHAN_MODE_MODIF_ACK:
+		rc = handle_modify_ack(msg);
+		break;
 	default:
 		break;
 	}
@@ -345,6 +417,43 @@ int gsm0408_rcvmsg(struct msgb *msg, u_int8_t link_id)
 	return rc;
 }
 
+/* handle ipaccess signals */
+static int handle_abisip_signal(unsigned int subsys, unsigned int signal,
+				 void *handler_data, void *signal_data)
+{
+	struct gsm_lchan *lchan = signal_data;
+	struct gsm_bts_trx_ts *ts;
+	int rc;
+
+	if (subsys != SS_ABISIP)
+		return 0;
+
+	ts = lchan->ts;
+
+	switch (signal) {
+	case S_ABISIP_CRCX_ACK:
+		/* we can ask it to connect now */
+		if (lchan->msc_data) {
+			DEBUGP(DMSC, "Connecting BTS to port: %d conn: %d\n",
+				lchan->msc_data->rtp_port, ts->abis_ip.conn_id);
+
+			rc = rsl_ipacc_mdcx(lchan, ntohl(local_addr.s_addr),
+					    lchan->msc_data->rtp_port,
+					    ts->abis_ip.conn_id,
+					    lchan->msc_data->rtp_payload2);
+			if (rc < 0) {
+				DEBUGP(DMSC, "Failed to send connect: %d\n", rc);
+				return rc;
+			}
+		}
+		break;
+	case S_ABISIP_DLCX_IND:
+		break;
+	}
+
+	return 0;
+}
+
 static void print_usage()
 {
 	printf("Usage: bsc_hack\n");
@@ -522,6 +631,7 @@ static void print_help()
 	printf("  -s --disable-color\n");
 	printf("  -c --config-file filename The config file to use.\n");
 	printf("  -m --msc=IP. The address of the MSC.\n");
+	printf("  -l --local=IP. The local address of the MGCP.\n");
 }
 
 static void handle_options(int argc, char** argv)
@@ -536,10 +646,11 @@ static void handle_options(int argc, char** argv)
 			{"timestamp", 0, 0, 'T'},
 			{"rtp-proxy", 0, 0, 'P'},
 			{"msc", 1, 0, 'm'},
+			{"local", 1, 0, 'l'},
 			{0, 0, 0, 0}
 		};
 
-		c = getopt_long(argc, argv, "hd:sTPc:m:",
+		c = getopt_long(argc, argv, "hd:sTPc:m:l:",
 				long_options, &option_index);
 		if (c == -1)
 			break;
@@ -567,6 +678,9 @@ static void handle_options(int argc, char** argv)
 		case 'm':
 			msc_address = strdup(optarg);
 			break;
+		case 'l':
+			inet_aton(optarg, &local_addr);
+			break;
 		default:
 			/* ignore */
 			break;
@@ -612,6 +726,9 @@ int main(int argc, char **argv)
 	sccp_connection_set_incoming(&sccp_ssn_bssap, msc_sccp_accept, NULL);
 	sccp_set_read(&sccp_ssn_bssap, msc_sccp_read, NULL);
 
+	/* initialize ipaccess handling */
+	register_signal_handler(SS_ABISIP, handle_abisip_signal, NULL);
+
 	rc = connect_to_msc(msc_address, 5000);
 	if (rc < 0) {
 		fprintf(stderr, "Opening the MSC connection failed.\n");
diff --git a/openbsc/src/bssap.c b/openbsc/src/bssap.c
index adf2cabcd..63bcc956b 100644
--- a/openbsc/src/bssap.c
+++ b/openbsc/src/bssap.c
@@ -44,6 +44,17 @@ static const struct tlv_definition bss_att_tlvdef = {
 		[GSM0808_IE_CELL_IDENTIFIER_LIST]   = { TLV_TYPE_TLV },
 		[GSM0808_IE_CHANNEL_NEEDED]	    = { TLV_TYPE_TV },
 		[GSM0808_IE_EMLPP_PRIORITY]	    = { TLV_TYPE_TV },
+		[GSM0808_IE_CHANNEL_TYPE]	    = { TLV_TYPE_TLV },
+		[GSM0808_IE_PRIORITY]		    = { TLV_TYPE_TLV },
+		[GSM0808_IE_CIRCUIT_IDENTITY_CODE]  = { TLV_TYPE_TV },
+		[GSM0808_IE_DOWNLINK_DTX_FLAG]	    = { TLV_TYPE_TV },
+		[GSM0808_IE_INTERFERENCE_BAND_TO_USE] = { TLV_TYPE_TV },
+		[GSM0808_IE_CLASSMARK_INFORMATION_T2] = { TLV_TYPE_TLV },
+		[GSM0808_IE_GROUP_CALL_REFERENCE]   = { TLV_TYPE_TLV },
+		[GSM0808_IE_TALKER_FLAG]	    = { TLV_TYPE_T },
+		[GSM0808_IE_CONFIG_EVO_INDI]	    = { TLV_TYPE_TV },
+		[GSM0808_IE_LSA_ACCESS_CTRL_SUPPR]  = { TLV_TYPE_TV },
+		[GSM0808_IE_SERVICE_HANDOVER]	    = { TLV_TYPE_TV},
 	},
 };
 
@@ -151,6 +162,7 @@ static int bssmap_handle_clear_command(struct sccp_connection *conn,
 
 	if (msg->lchan) {
 		DEBUGP(DMSC, "Releasing all transactions on %p\n", conn);
+		bsc_del_timer(&msg->lchan->msc_data->T10);
 		msg->lchan->msc_data->lchan = NULL;
 		msg->lchan->msc_data = NULL;
 		put_lchan(msg->lchan);
@@ -210,6 +222,75 @@ reject:
 	return -1;
 }
 
+/*
+ * Handle the network configurable T10 parameter
+ */
+static void bssmap_t10_fired(void *_conn)
+{
+	struct sccp_connection *conn = (struct sccp_connection *) _conn;
+	struct msgb *resp;
+
+	DEBUGP(DMSC, "T10 fired, assignment failed: %p\n", conn);
+	resp = bssmap_create_assignment_failure(
+		GSM0808_CAUSE_NO_RADIO_RESOURCE_AVAILABLE, NULL);
+	if (!resp) {
+		DEBUGP(DMSC, "Allocation failure: %p\n", conn);
+		return;
+	}
+
+	bsc_queue_connection_write(conn, resp);
+}
+
+/*
+ * Handle the assignment request message.
+ *
+ * See §3.2.1.1 for the message type
+ */
+static int bssmap_handle_assignm_req(struct sccp_connection *conn,
+				     struct msgb *msg, unsigned int length)
+{
+	struct tlv_parsed tp;
+	struct bss_sccp_connection_data *msc_data;
+	int ret = 0;
+
+	if (!msg->lchan || !msg->lchan->msc_data) {
+		DEBUGP(DMSC, "No lchan/msc_data in cipher mode command.\n");
+		goto reject;
+	}
+
+	msc_data = msg->lchan->msc_data;
+	tlv_parse(&tp, &bss_att_tlvdef, msg->l4h + 1, length - 1, 0, 0);
+
+	if (!TLVP_PRESENT(&tp, GSM0808_IE_CHANNEL_TYPE)) {
+		DEBUGP(DMSC, "Mandantory channel type not present.\n");
+		goto reject;
+	}
+
+	if (!TLVP_PRESENT(&tp, GSM0808_IE_CIRCUIT_IDENTITY_CODE)) {
+		DEBUGP(DMSC, "Identity code missing. Audio routing will not work.\n");
+		goto reject;
+	}
+
+	/*
+	 * currently only activation of speach on the
+	 * existing channel is supported. This means we
+	 * will send a Channel Modify message and take it
+	 * from there.
+	 * Setup channel type, timer
+	 */
+	//gsm48_lchan_modify();
+
+	msc_data->T10.cb = bssmap_t10_fired;
+	msc_data->T10.data = conn;
+	bsc_schedule_timer(&msc_data->T10, GSM0808_T10_VALUE);
+	return ret;
+
+reject:
+	gsm0808_send_assignment_failure(msg->lchan,
+					GSM0808_CAUSE_NO_RADIO_RESOURCE_AVAILABLE, NULL);
+	return -1;
+}
+
 int bssmap_rcvmsg_udt(struct gsm_network *net, struct msgb *msg, unsigned int length)
 {
 	int ret = 0;
@@ -247,6 +328,9 @@ int bssmap_rcvmsg_dt1(struct sccp_connection *conn, struct msgb *msg, unsigned i
 	case BSS_MAP_MSG_CIPHER_MODE_CMD:
 		ret = bssmap_handle_cipher_mode(conn, msg, length);
 		break;
+	case BSS_MAP_MSG_ASSIGMENT_RQST:
+		ret = bssmap_handle_assignm_req(conn, msg, length);
+		break;
 	default:
 		DEBUGP(DMSC, "Unimplemented msg type: %d\n", msg->l4h[0]);
 		break;
@@ -442,6 +526,156 @@ struct msgb *bssmap_create_sapi_reject(u_int8_t link_id)
 	return msg;
 }
 
+static u_int8_t chan_mode_to_speech(enum gsm48_chan_mode mode)
+{
+	switch (mode) {
+	case GSM48_CMODE_SPEECH_V1:
+		return 1;
+		break;
+	case GSM48_CMODE_SPEECH_EFR:
+		return 0x11;
+		break;
+	case GSM48_CMODE_SPEECH_AMR:
+		return 0x21;
+		break;
+	case GSM48_CMODE_SIGN:
+	case GSM48_CMODE_DATA_14k5:
+	case GSM48_CMODE_DATA_12k0:
+	case GSM48_CMODE_DATA_6k0:
+	case GSM48_CMODE_DATA_3k6:
+	default:
+		DEBUGP(DMSC, "Using non speech mode: %d\n", mode);
+		return 0;
+		break;
+	}
+}
+
+/* 3.2.2.33 */
+static u_int8_t lchan_to_chosen_channel(struct gsm_lchan *lchan)
+{
+	u_int8_t channel_mode = 0, channel = 0;
+
+	switch (lchan->tch_mode) {
+	case GSM48_CMODE_SPEECH_V1:
+	case GSM48_CMODE_SPEECH_EFR:
+	case GSM48_CMODE_SPEECH_AMR:
+		channel_mode = 0x9;
+		break;
+	case GSM48_CMODE_SIGN:
+		channel_mode = 0x8;
+		break;
+	case GSM48_CMODE_DATA_14k5:
+		channel_mode = 0xe;
+		break;
+	case GSM48_CMODE_DATA_12k0:
+		channel_mode = 0xb;
+		break;
+	case GSM48_CMODE_DATA_6k0:
+		channel_mode = 0xc;
+		break;
+	case GSM48_CMODE_DATA_3k6:
+		channel_mode = 0xd;
+		break;
+	}
+
+	switch (lchan->type) {
+	case GSM_LCHAN_NONE:
+		channel = 0x0;
+		break;
+	case GSM_LCHAN_SDCCH:
+		channel = 0x1;
+		break;
+	case GSM_LCHAN_TCH_F:
+		channel = 0x8;
+		break;
+	case GSM_LCHAN_TCH_H:
+		channel = 0x9;
+		break;
+	case GSM_LCHAN_UNKNOWN:
+		DEBUGP(DMSC, "Unknown lchan type: %p\n", lchan);
+		break;
+	}
+
+	return channel_mode << 4 | channel;
+}
+
+struct msgb *bssmap_create_assignment_completed(struct gsm_lchan *lchan, u_int8_t rr_cause)
+{
+	u_int8_t *data;
+	u_int8_t speech_mode;
+
+	struct msgb *msg = msgb_alloc(35, "bssmap: ass compl");
+	if (!msg)
+		return NULL;
+
+	msg->l3h = msgb_put(msg, 3);
+	msg->l3h[0] = BSSAP_MSG_BSS_MANAGEMENT;
+	msg->l3h[1] = 0xff;
+	msg->l3h[2] = BSS_MAP_MSG_ASSIGMENT_COMPLETE;
+
+	/* write 3.2.2.22 */
+	data = msgb_put(msg, 2);
+	data[0] = GSM0808_IE_RR_CAUSE;
+	data[1] = rr_cause;
+
+	/* write cirtcuit identity  code 3.2.2.2 */
+	/* write cell identifier 3.2.2.17 */
+	/* write chosen channel 3.2.2.33 when BTS picked it */
+	data = msgb_put(msg, 2);
+	data[0] = GSM0808_IE_CHOSEN_CHANNEL;
+	data[1] = lchan_to_chosen_channel(lchan);
+
+	/* write chosen encryption algorithm 3.2.2.44 */
+	data = msgb_put(msg, 2);
+	data[0] = GSM0808_IE_CHOSEN_ENCR_ALG;
+	data[1] = RSL_ENC_ALG_A5(lchan->encr.alg_id);
+
+	/* write circuit pool 3.2.2.45 */
+	/* write speech version chosen: 3.2.2.51 when BTS picked it */
+	speech_mode = chan_mode_to_speech(lchan->tch_mode);
+	if (speech_mode != 0) {
+		data = msgb_put(msg, 2);
+		data[0] = GSM0808_IE_SPEECH_VERSION;
+		data[1] = speech_mode;
+	}
+
+	/* write LSA identifier 3.2.2.15 */
+
+
+	/* update the size */
+	msg->l3h[1] = msgb_l3len(msg) - 2;
+	return msg;
+}
+
+struct msgb *bssmap_create_assignment_failure(u_int8_t cause, u_int8_t *rr_cause)
+{
+	u_int8_t *data;
+	struct msgb *msg = msgb_alloc(35, "bssmap: ass fail");
+	if (!msg)
+		return NULL;
+
+	msg->l3h = msgb_put(msg, 5);
+	msg->l3h[0] = BSSAP_MSG_BSS_MANAGEMENT;
+	msg->l3h[1] = 0xff;
+	msg->l3h[2] = BSS_MAP_MSG_ASSIGMENT_FAILURE;
+	msg->l3h[3] = GSM0808_IE_CAUSE;
+	msg->l3h[4] = cause;
+
+	/* RR cause 3.2.2.22 */
+	if (rr_cause) {
+		data = msgb_put(msg, 2);
+		data[0] = GSM0808_IE_RR_CAUSE;
+		data[1] = *rr_cause;
+	}
+
+	/* Circuit pool 3.22.45 */
+	/* Circuit pool list 3.2.2.46 */
+
+	/* update the size */
+	msg->l3h[1] = msgb_l3len(msg) - 2;
+	return msg;
+}
+
 struct msgb *dtap_create_msg(struct msgb *msg_l3, u_int8_t link_id)
 {
 	struct dtap_header *header;
@@ -484,6 +718,7 @@ static int bssap_handle_lchan_signal(unsigned int subsys, unsigned int signal,
 	if (!lchan || !lchan->msc_data)
 		return 0;
 
+	bsc_del_timer(&lchan->msc_data->T10);
 	conn = lchan->msc_data->sccp;
 	lchan->msc_data->lchan = NULL;
 	lchan->msc_data = NULL;
@@ -667,6 +902,34 @@ void bts_send_queued(struct bss_sccp_connection_data *data)
 	data->gsm_queue_size = 0;
 }
 
+void gsm0808_send_assignment_failure(struct gsm_lchan *lchan, u_int8_t cause, u_int8_t *rr_value)
+{
+	struct msgb *resp;
+
+	bsc_del_timer(&lchan->msc_data->T10);
+	resp = bssmap_create_assignment_failure(cause, rr_value);
+	if (!resp) {
+		DEBUGP(DMSC, "Allocation failure: %p\n", lchan_get_sccp(lchan));
+		return;
+	}
+
+	bsc_queue_connection_write(lchan_get_sccp(lchan), resp);
+}
+
+void gsm0808_send_assignment_compl(struct gsm_lchan *lchan, u_int8_t rr_cause)
+{
+	struct msgb *resp;
+
+	bsc_del_timer(&lchan->msc_data->T10);
+	resp = bssmap_create_assignment_completed(lchan, rr_cause);
+	if (!resp) {
+		DEBUGP(DMSC, "Creating MSC response failed: %p\n", lchan_get_sccp(lchan));
+		return;
+	}
+
+	bsc_queue_connection_write(lchan_get_sccp(lchan), resp);
+}
+
 static __attribute__((constructor)) void on_dso_load_bssap(void)
 {
 	register_signal_handler(SS_LCHAN, bssap_handle_lchan_signal, NULL);