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

6 files changed, 71 insertions, 95 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);
diff --git a/src/osmo-bsc/osmo_bsc_bssap.c b/src/osmo-bsc/osmo_bsc_bssap.c
index d07cc558e..db749a3da 100644
--- a/src/osmo-bsc/osmo_bsc_bssap.c
+++ b/src/osmo-bsc/osmo_bsc_bssap.c
@@ -262,15 +262,14 @@ page_subscriber(struct bsc_msc_data *msc, struct gsm_bts *bts,
 
 /* Decode 5-byte LAI list element data (see TS 08.08 3.2.2.27) into MCC/MNC/LAC.
  * Return 0 if successful, negative on error. */
-static int
-decode_lai(const uint8_t *data, uint16_t *mcc, uint16_t *mnc, uint16_t *lac)
+static void
+decode_lai(const uint8_t *data, struct osmo_location_area_id *laid)
 {
 	struct gsm48_loc_area_id lai;
 
 	/* Copy data to stack to prevent unaligned access in gsm48_decode_lai(). */
 	memcpy(&lai, data, sizeof(lai)); /* don't byte swap yet */
-
-	return gsm48_decode_lai(&lai, mcc, mnc, lac) != 0 ? -1 : 0;
+	gsm48_decode_lai2(&lai, laid);
 }
 
 static void
@@ -290,37 +289,33 @@ page_cgi(struct bsc_msc_data *msc, const uint8_t *data, uint8_t data_length, siz
 	uint16_t ci;
 	int i = 0;
 	while (remain >= sizeof(struct gsm48_loc_area_id) + sizeof(ci)) {
-		uint16_t mcc, mnc, lac, *ci_be;
+		struct osmo_location_area_id lai;
+		uint16_t *ci_be;
 		size_t lai_offset = 1 + i * (sizeof(struct gsm48_loc_area_id) + sizeof(ci));
-		if (decode_lai(&data[lai_offset], &mcc, &mnc, &lac) != 0) {
-			LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Invalid LAI in Cell Identifier List "
-			     "for BSS (0x%x), paging entire BSS anyway (%s)\n",
-			     mi_string, CELL_IDENT_BSS, osmo_hexdump(data, data_length));
-			page_all_bts(msc, tmsi, mi_string, chan_needed);
-			return;
-		}
+		decode_lai(&data[lai_offset], &lai);
 		ci_be = (uint16_t *)(&data[lai_offset + sizeof(struct gsm48_loc_area_id)]);
 		ci = osmo_load16be(ci_be);
-		if (mcc == msc->network->country_code && mnc == msc->network->network_code) {
+		if (!osmo_plmn_cmp(&lai.plmn, &msc->network->plmn)) {
 			int paged = 0;
 			struct gsm_bts *bts;
 			llist_for_each_entry(bts, &msc->network->bts_list, list) {
-				if (bts->location_area_code != lac)
+				if (bts->location_area_code != lai.lac)
 					continue;
 				if (bts->cell_identity != ci)
 					continue;
 				/* ignore errors from page_subscriber(); keep trying other BTS */
-				page_subscriber(msc, bts, tmsi, lac, mi_string, chan_needed);
+				page_subscriber(msc, bts, tmsi, lai.lac, mi_string, chan_needed);
 				paged = 1;
 			}
 			if (!paged) {
 				LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with LAC %d and CI %d not found\n",
-				     mi_string, lac, ci);
+				     mi_string, lai.lac, ci);
 			}
 		} else {
-			LOGP(DMSC, LOGL_DEBUG, "Paging IMSI %s: MCC/MNC in Cell Identifier List "
-			     "(%d/%d) do not match our network (%d/%d)\n", mi_string, mcc, mnc,
-			     msc->network->country_code, msc->network->network_code);
+			LOGP(DMSC, LOGL_DEBUG, "Paging IMSI %s: MCC-MNC in Cell Identifier List "
+			     "(%s) do not match our network (%s)\n",
+			     mi_string, osmo_plmn_name(&lai.plmn),
+			     osmo_plmn_name2(&msc->network->plmn));
 		}
 		remain -= sizeof(struct gsm48_loc_area_id) + sizeof(ci);
 		i++;
@@ -389,32 +384,27 @@ page_lai_and_lac(struct bsc_msc_data *msc, const uint8_t *data, size_t data_leng
 {
 	int i = 0;
 	while (remain >= sizeof(struct gsm48_loc_area_id)) {
-		uint16_t mcc, mnc, lac;
-		if (decode_lai(&data[1 + i * sizeof(struct gsm48_loc_area_id)], &mcc, &mnc, &lac) != 0) {
-			LOGP(DMSC, LOGL_ERROR, "Paging IMSI %s: Invalid LAI in Cell Identifier List "
-			     "for BSS (0x%x), paging entire BSS anyway (%s)\n",
-			     mi_string, CELL_IDENT_BSS, osmo_hexdump(data, data_length));
-			page_all_bts(msc, tmsi, mi_string, chan_needed);
-			return;
-		}
-		if (mcc == msc->network->country_code && mnc == msc->network->network_code) {
+		struct osmo_location_area_id lai;
+		decode_lai(&data[1 + i * sizeof(struct gsm48_loc_area_id)], &lai);
+		if (!osmo_plmn_cmp(&lai.plmn, &msc->network->plmn)) {
 			int paged = 0;
 			struct gsm_bts *bts;
 			llist_for_each_entry(bts, &msc->network->bts_list, list) {
-				if (bts->location_area_code != lac)
+				if (bts->location_area_code != lai.lac)
 					continue;
 				/* ignore errors from page_subscriber(); keep trying other BTS */
-				page_subscriber(msc, bts, tmsi, lac, mi_string, chan_needed);
+				page_subscriber(msc, bts, tmsi, lai.lac, mi_string, chan_needed);
 				paged = 1;
 			}
 			if (!paged) {
 				LOGP(DMSC, LOGL_NOTICE, "Paging IMSI %s: BTS with LAC %d not found\n",
-				     mi_string, lac);
+				     mi_string, lai.lac);
 			}
 		} else {
-			LOGP(DMSC, LOGL_DEBUG, "Paging IMSI %s: MCC/MNC in Cell Identifier List "
-			     "(%d/%d) do not match our network (%d/%d)\n", mi_string, mcc, mnc,
-			     msc->network->country_code, msc->network->network_code);
+			LOGP(DMSC, LOGL_DEBUG, "Paging IMSI %s: MCC-MNC in Cell Identifier List "
+			     "(%s) do not match our network (%s)\n",
+			     mi_string, osmo_plmn_name(&lai.plmn),
+			     osmo_plmn_name2(&msc->network->plmn));
 		}
 		remain -= sizeof(struct gsm48_loc_area_id);
 		i++;
diff --git a/src/osmo-bsc/osmo_bsc_ctrl.c b/src/osmo-bsc/osmo_bsc_ctrl.c
index 6092f2379..5f88b85f7 100644
--- a/src/osmo-bsc/osmo_bsc_ctrl.c
+++ b/src/osmo-bsc/osmo_bsc_ctrl.c
@@ -207,10 +207,11 @@ static void generate_location_state_trap(struct gsm_bts *bts, struct bsc_msc_con
 	policy = osmo_bsc_rf_get_policy_name(osmo_bsc_rf_get_policy_by_bts(bts));
 
 	cmd->reply = talloc_asprintf_append(cmd->reply,
-				",%s,%s,%s,%d,%d",
+				",%s,%s,%s,%s,%s",
 				oper, admin, policy,
-				bts->network->country_code,
-				bts->network->network_code);
+				osmo_mcc_name(bts->network->plmn.mcc),
+				osmo_mnc_name(bts->network->plmn.mnc,
+					      bts->network->plmn.mnc_3_digits));
 
 	osmo_bsc_send_trap(cmd, msc_con);
 	talloc_free(cmd);
diff --git a/src/osmo-bsc/osmo_bsc_filter.c b/src/osmo-bsc/osmo_bsc_filter.c
index c1f3e80a6..5f60989a7 100644
--- a/src/osmo-bsc/osmo_bsc_filter.c
+++ b/src/osmo-bsc/osmo_bsc_filter.c
@@ -36,21 +36,16 @@ static void handle_lu_request(struct gsm_subscriber_connection *conn,
 	struct gsm48_hdr *gh;
 	struct gsm48_loc_upd_req *lu;
 	struct gsm48_loc_area_id lai;
-	struct gsm_network *net;
-	struct gsm_bts *bts = conn_get_bts(conn);
 
 	if (msgb_l3len(msg) < sizeof(*gh) + sizeof(*lu)) {
 		LOGP(DMSC, LOGL_ERROR, "LU too small to look at: %u\n", msgb_l3len(msg));
 		return;
 	}
 
-	net = bts->network;
-
 	gh = msgb_l3(msg);
 	lu = (struct gsm48_loc_upd_req *) gh->data;
 
-	gsm48_generate_lai(&lai, net->country_code, net->network_code,
-			   bts->location_area_code);
+	gsm48_generate_lai2(&lai, bts_lai(conn_get_bts(conn)));
 
 	if (memcmp(&lai, &lu->lai, sizeof(lai)) != 0) {
 		LOGP(DMSC, LOGL_DEBUG, "Marking con for welcome USSD.\n");
@@ -315,9 +310,9 @@ static int bsc_patch_mm_info(struct gsm_subscriber_connection *conn,
 
 static int has_core_identity(struct bsc_msc_data *msc)
 {
-	if (msc->core_mnc != -1)
+	if (msc->core_plmn.mnc != GSM_MCC_MNC_INVALID)
 		return 1;
-	if (msc->core_mcc != -1)
+	if (msc->core_plmn.mcc != GSM_MCC_MNC_INVALID)
 		return 1;
 	if (msc->core_lac != -1)
 		return 1;
@@ -332,8 +327,6 @@ static int has_core_identity(struct bsc_msc_data *msc)
 int bsc_scan_msc_msg(struct gsm_subscriber_connection *conn, struct msgb *msg)
 {
 	struct bsc_msc_data *msc;
-	struct gsm_bts *bts = conn_get_bts(conn);
-	struct gsm_network *net;
 	struct gsm48_loc_area_id *lai;
 	struct gsm48_hdr *gh;
 	uint8_t pdisc;
@@ -353,7 +346,6 @@ int bsc_scan_msc_msg(struct gsm_subscriber_connection *conn, struct msgb *msg)
 		return 0;
 
 	mtype = gsm48_hdr_msg_type(gh);
-	net = bts->network;
 	msc = conn->sccp.msc;
 
 	if (mtype == GSM48_MT_MM_LOC_UPD_ACCEPT) {
@@ -361,9 +353,7 @@ int bsc_scan_msc_msg(struct gsm_subscriber_connection *conn, struct msgb *msg)
 			if (msgb_l3len(msg) >= sizeof(*gh) + sizeof(*lai)) {
 				/* overwrite LAI in the message */
 				lai = (struct gsm48_loc_area_id *) &gh->data[0];
-				gsm48_generate_lai(lai, net->country_code,
-						   net->network_code,
-						   bts->location_area_code);
+				gsm48_generate_lai2(lai, bts_lai(conn_get_bts(conn)));
 			}
 		}
 
diff --git a/src/osmo-bsc/osmo_bsc_msc.c b/src/osmo-bsc/osmo_bsc_msc.c
index 46be2e644..e0c7556a9 100644
--- a/src/osmo-bsc/osmo_bsc_msc.c
+++ b/src/osmo-bsc/osmo_bsc_msc.c
@@ -581,8 +581,10 @@ struct bsc_msc_data *osmo_msc_data_alloc(struct gsm_network *net, int nr)
 	INIT_LLIST_HEAD(&msc_data->dests);
 	msc_data->ping_timeout = 20;
 	msc_data->pong_timeout = 5;
-	msc_data->core_mnc = -1;
-	msc_data->core_mcc = -1;
+	msc_data->core_plmn = (struct osmo_plmn_id){
+		.mcc = GSM_MCC_MNC_INVALID,
+		.mnc = GSM_MCC_MNC_INVALID,
+	};
 	msc_data->core_ci = -1;
 	msc_data->core_lac = -1;
 	msc_data->rtp_base = 4000;
diff --git a/src/osmo-bsc/osmo_bsc_vty.c b/src/osmo-bsc/osmo_bsc_vty.c
index e173b4a7b..3455d01af 100644
--- a/src/osmo-bsc/osmo_bsc_vty.c
+++ b/src/osmo-bsc/osmo_bsc_vty.c
@@ -27,6 +27,7 @@
 #include <osmocom/bsc/bsc_msg_filter.h>
 
 #include <osmocom/core/talloc.h>
+#include <osmocom/gsm/gsm48.h>
 #include <osmocom/vty/logging.h>
 #include <osmocom/mgcp_client/mgcp_client.h>
 
@@ -107,12 +108,12 @@ static void write_msc(struct vty *vty, struct bsc_msc_data *msc)
 	struct bsc_msc_dest *dest;
 
 	vty_out(vty, "msc %d%s", msc->nr, VTY_NEWLINE);
-	if (msc->core_mnc != -1)
-		vty_out(vty, " core-mobile-network-code %d%s",
-			msc->core_mnc, VTY_NEWLINE);
-	if (msc->core_mcc != -1)
-		vty_out(vty, " core-mobile-country-code %d%s",
-			msc->core_mcc, VTY_NEWLINE);
+	if (msc->core_plmn.mnc != GSM_MCC_MNC_INVALID)
+		vty_out(vty, " core-mobile-network-code %s%s",
+			osmo_mnc_name(msc->core_plmn.mnc, msc->core_plmn.mnc_3_digits), VTY_NEWLINE);
+	if (msc->core_plmn.mcc != GSM_MCC_MNC_INVALID)
+		vty_out(vty, " core-mobile-country-code %s%s",
+			osmo_mcc_name(msc->core_plmn.mcc), VTY_NEWLINE);
 	if (msc->core_lac != -1)
 		vty_out(vty, " core-location-area-code %d%s",
 			msc->core_lac, VTY_NEWLINE);
@@ -236,7 +237,15 @@ DEFUN(cfg_net_bsc_ncc,
       "Use this network code for the core network\n" "MNC value\n")
 {
 	struct bsc_msc_data *data = bsc_msc_data(vty);
-	data->core_mnc = atoi(argv[0]);
+	uint16_t mnc;
+	bool mnc_3_digits;
+
+	if (osmo_mnc_from_str(argv[0], &mnc, &mnc_3_digits)) {
+		vty_out(vty, "%% Error decoding MNC: %s%s", argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	data->core_plmn.mnc = mnc;
+	data->core_plmn.mnc_3_digits = mnc_3_digits;
 	return CMD_SUCCESS;
 }
 
@@ -245,8 +254,13 @@ DEFUN(cfg_net_bsc_mcc,
       "core-mobile-country-code <1-999>",
       "Use this country code for the core network\n" "MCC value\n")
 {
+	uint16_t mcc;
 	struct bsc_msc_data *data = bsc_msc_data(vty);
-	data->core_mcc = atoi(argv[0]);
+	if (osmo_mcc_from_str(argv[0], &mcc)) {
+		vty_out(vty, "%% Error decoding MCC: %s%s", argv[0], VTY_NEWLINE);
+		return CMD_WARNING;
+	}
+	data->core_plmn.mcc = mcc;
 	return CMD_SUCCESS;
 }