implement support for 3-digit MNC with leading zeros

Add 3-digit flags and use the new RAI and LAI API from libosmocore throughout
the code base to be able to handle an MNC < 100 that has three digits (leading
zeros).

The changes to abis_test and gsm0408_test show that this code now handles
3-digit MNC correctly, by not dropping the leading zero as 0xf in the encoded
PLMN.

Re-implement CTRL commands 'mcc', 'mnc' and 'mcc-mnc-apply' to preserve the
presence of the third digit of the MNC. Always reply with all leading zeros.
Adjust the expected results in ctrl_test_runner.py, to show that it works.

In VTY and CTRL, the parsing of MCC and MNC is inherently made stricter by use
of osmo_{mcc,mnc}_from_str() -- they will no longer allow surplus characters
and detect errno returned by strtol() (in contrast to atoi()).

Depends: Id2240f7f518494c9df6c8bda52c0d5092f90f221 (libosmocore),
	 Ib7176b1d65a03b76f41f94bc9d3293a8a07d24c6 (libosmocore),
	 I020a4f11791c61742a3d795f782805f7b7e8733e (libosmocore)
Change-Id: I8e722103344186fde118b26d8353db95a4581daa

1 files changed, 13 insertions, 34 deletions

diff --git a/src/osmo-bsc/osmo_bsc_api.c b/src/osmo-bsc/osmo_bsc_api.c
index 465832c82..75dae1293 100644
--- a/src/osmo-bsc/osmo_bsc_api.c
+++ b/src/osmo-bsc/osmo_bsc_api.c
@@ -54,32 +54,20 @@ static int bsc_clear_request(struct gsm_subscriber_connection *conn, uint32_t ca
 static int complete_layer3(struct gsm_subscriber_connection *conn,
 			   struct msgb *msg, struct bsc_msc_data *msc);
 
-static uint16_t get_network_code_for_msc(struct bsc_msc_data *msc)
+static struct osmo_cell_global_id *cgi_for_msc(struct bsc_msc_data *msc, struct gsm_bts *bts)
 {
-	if (msc->core_mnc != -1)
-		return msc->core_mnc;
-	return msc->network->network_code;
-}
-
-static uint16_t get_country_code_for_msc(struct bsc_msc_data *msc)
-{
-	if (msc->core_mcc != -1)
-		return msc->core_mcc;
-	return msc->network->country_code;
-}
-
-static uint16_t get_lac_for_msc(struct bsc_msc_data *msc, struct gsm_bts *bts)
-{
-	if (msc->core_lac != -1)
-		return msc->core_lac;
-	return bts->location_area_code;
-}
+	static struct osmo_cell_global_id cgi;
+	cgi.lai.plmn = msc->network->plmn;
+	if (msc->core_plmn.mcc != GSM_MCC_MNC_INVALID)
+		cgi.lai.plmn.mcc = msc->core_plmn.mcc;
+	if (msc->core_plmn.mnc != GSM_MCC_MNC_INVALID) {
+		cgi.lai.plmn.mnc = msc->core_plmn.mnc;
+		cgi.lai.plmn.mnc_3_digits = msc->core_plmn.mnc_3_digits;
+	}
+	cgi.lai.lac = (msc->core_lac != -1) ? msc->core_lac : bts->location_area_code;
+	cgi.cell_identity = (msc->core_ci != -1) ? msc->core_ci : bts->cell_identity;
 
-static uint16_t get_ci_for_msc(struct bsc_msc_data *msc, struct gsm_bts *bts)
-{
-	if (msc->core_ci != -1)
-		return msc->core_ci;
-	return bts->cell_identity;
+	return &cgi;
 }
 
 static void bsc_maybe_lu_reject(struct gsm_subscriber_connection *conn, int con_type, int cause)
@@ -242,10 +230,6 @@ static int complete_layer3(struct gsm_subscriber_connection *conn,
 	char *imsi = NULL;
 	struct timeval tv;
 	struct msgb *resp;
-	uint16_t network_code;
-	uint16_t country_code;
-	uint16_t lac;
-	uint16_t ci;
 	enum bsc_con ret;
 	int send_ping = msc->advanced_ping;
 
@@ -285,14 +269,9 @@ static int complete_layer3(struct gsm_subscriber_connection *conn,
 
 	/* check return value, if failed check msg for and send USSD */
 
-	network_code = get_network_code_for_msc(conn->sccp.msc);
-	country_code = get_country_code_for_msc(conn->sccp.msc);
-	lac = get_lac_for_msc(conn->sccp.msc, conn_get_bts(conn));
-	ci = get_ci_for_msc(conn->sccp.msc, conn_get_bts(conn));
-
 	bsc_scan_bts_msg(conn, msg);
 
-	resp = gsm0808_create_layer3(msg, network_code, country_code, lac, ci);
+	resp = gsm0808_create_layer3_2(msg, cgi_for_msc(conn->sccp.msc, conn_get_bts(conn)), NULL);
 	if (!resp) {
 		LOGP(DMSC, LOGL_DEBUG, "Failed to create layer3 message.\n");
 		osmo_bsc_sigtran_del_conn(conn);