Add vty `reject-cause` to set the reject cause

Allow to set the LU reject cause independently for both of the
following cases; either when an IMSI is unknown to the HLR or
when the mslookup client does not a receive a timely response
to a GSUP request for the remote home HLR.

Original patchset modified by <keith@rhizomatica.org>

Change-Id: Icea39020c23fbbea9e92847df76af8986fdbf48a

7 files changed, 98 insertions, 6 deletions

diff --git a/include/osmocom/hlr/hlr.h b/include/osmocom/hlr/hlr.h
index 3acb3c5..b27fb3d 100644
--- a/include/osmocom/hlr/hlr.h
+++ b/include/osmocom/hlr/hlr.h
@@ -23,6 +23,7 @@
 #pragma once
 
 #include <stdbool.h>
+#include <osmocom/gsm/protocol/gsm_04_08_gprs.h>
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/gsm/ipa.h>
 #include <osmocom/core/tdef.h>
@@ -55,6 +56,8 @@ struct hlr {
 
 	struct llist_head euse_list;
 	struct hlr_euse *euse_default;
+	enum gsm48_gmm_cause reject_cause;
+	enum gsm48_gmm_cause no_proxy_reject_cause;
 
 	/* NCSS (call independent) session guard timeout value */
 	int ncss_guard_timeout;
diff --git a/include/osmocom/hlr/hlr_vty.h b/include/osmocom/hlr/hlr_vty.h
index 10eddc3..83691b8 100644
--- a/include/osmocom/hlr/hlr_vty.h
+++ b/include/osmocom/hlr/hlr_vty.h
@@ -45,5 +45,5 @@ enum hlr_vty_node {
 
 int hlr_vty_is_config_node(struct vty *vty, int node);
 int hlr_vty_go_parent(struct vty *vty);
-void hlr_vty_init(void);
+void hlr_vty_init(void *hlr_ctx);
 void dgsm_vty_init(void);
diff --git a/src/hlr.c b/src/hlr.c
index c6ae4fc..8183d9b 100644
--- a/src/hlr.c
+++ b/src/hlr.c
@@ -324,7 +324,7 @@ static int rx_send_auth_info(struct osmo_gsup_req *req)
 						  " Returning slightly inaccurate cause 'IMSI Unknown' via GSUP");
 			return rc;
 		case -ENOENT:
-			osmo_gsup_req_respond_err(req, GMM_CAUSE_IMSI_UNKNOWN, "IMSI unknown");
+			osmo_gsup_req_respond_err(req, g_hlr->reject_cause, "IMSI unknown");
 			return rc;
 		default:
 			osmo_gsup_req_respond_err(req, GMM_CAUSE_NET_FAIL, "failure to look up IMSI in db");
@@ -759,6 +759,8 @@ int main(int argc, char **argv)
 	g_hlr->db_file_path = talloc_strdup(g_hlr, HLR_DEFAULT_DB_FILE_PATH);
 	g_hlr->mslookup.server.mdns.domain_suffix = talloc_strdup(g_hlr, OSMO_MDNS_DOMAIN_SUFFIX_DEFAULT);
 	g_hlr->mslookup.client.mdns.domain_suffix = talloc_strdup(g_hlr, OSMO_MDNS_DOMAIN_SUFFIX_DEFAULT);
+	g_hlr->reject_cause = GMM_CAUSE_IMSI_UNKNOWN;
+	g_hlr->no_proxy_reject_cause = GMM_CAUSE_IMSI_UNKNOWN;
 
 	/* Init default (call independent) SS session guard timeout value */
 	g_hlr->ncss_guard_timeout = NCSS_GUARD_TIMEOUT_DEFAULT;
@@ -775,7 +777,7 @@ int main(int argc, char **argv)
 	osmo_stats_init(hlr_ctx);
 	vty_init(&vty_info);
 	ctrl_vty_init(hlr_ctx);
-	hlr_vty_init();
+	hlr_vty_init(hlr_ctx);
 	dgsm_vty_init();
 	osmo_cpu_sched_vty_init(hlr_ctx);
 	handle_options(argc, argv);
diff --git a/src/hlr_vty.c b/src/hlr_vty.c
index a440c42..02e0cde 100644
--- a/src/hlr_vty.c
+++ b/src/hlr_vty.c
@@ -25,7 +25,10 @@
  *
  */
 
+#include <errno.h>
+
 #include <osmocom/core/talloc.h>
+#include <osmocom/gsm/protocol/gsm_04_08_gprs.h>
 #include <osmocom/vty/vty.h>
 #include <osmocom/vty/stats.h>
 #include <osmocom/vty/command.h>
@@ -40,6 +43,36 @@
 #include <osmocom/hlr/hlr_ussd.h>
 #include <osmocom/hlr/gsup_server.h>
 
+static const struct value_string gsm48_gmm_cause_vty_names[] = {
+	{ GMM_CAUSE_IMSI_UNKNOWN,	"imsi-unknown" },
+	{ GMM_CAUSE_ILLEGAL_MS,		"illegal-ms" },
+	{ GMM_CAUSE_PLMN_NOTALLOWED,	"plmn-not-allowed" },
+	{ GMM_CAUSE_LA_NOTALLOWED,	"la-not-allowed" },
+	{ GMM_CAUSE_ROAMING_NOTALLOWED,	"roaming-not-allowed" },
+	{ GMM_CAUSE_NO_SUIT_CELL_IN_LA,	"no-suitable-cell-in-la" },
+	{ GMM_CAUSE_NET_FAIL,		"net-fail" },
+	{ GMM_CAUSE_CONGESTION,		"congestion" },
+	{ GMM_CAUSE_GSM_AUTH_UNACCEPT,	"auth-unacceptable" },
+	{ GMM_CAUSE_PROTO_ERR_UNSPEC,	"proto-error-unspec" },
+	{ 0, NULL },
+};
+
+/* TS 24.008 4.4.4.7 */
+static const struct value_string gsm48_gmm_cause_vty_descs[] = {
+	{ GMM_CAUSE_IMSI_UNKNOWN,	" #02: (IMSI unknown in HLR)" },
+	{ GMM_CAUSE_ILLEGAL_MS,		" #03  (Illegal MS)" },
+	{ GMM_CAUSE_PLMN_NOTALLOWED,	" #11: (PLMN not allowed)" },
+	{ GMM_CAUSE_LA_NOTALLOWED,	" #12: (Location Area not allowed)" },
+	{ GMM_CAUSE_ROAMING_NOTALLOWED,	" #13: (Roaming not allowed in this location area)" },
+	{ GMM_CAUSE_NO_SUIT_CELL_IN_LA,	" #15: (No Suitable Cells In Location Area [continue search in PLMN])." },
+	{ GMM_CAUSE_NET_FAIL,		" #17: (Network Failure)" },
+	{ GMM_CAUSE_CONGESTION,		" #22: (Congestion)" },
+	{ GMM_CAUSE_GSM_AUTH_UNACCEPT,	" #23: (GSM authentication unacceptable [UMTS])" },
+	{ GMM_CAUSE_PROTO_ERR_UNSPEC,	"#111: (Protocol error, unspecified)" },
+	{ 0, NULL },
+};
+
+
 struct cmd_node hlr_node = {
 	HLR_NODE,
 	"%s(config-hlr)# ",
@@ -73,6 +106,15 @@ DEFUN(cfg_gsup,
 static int config_write_hlr(struct vty *vty)
 {
 	vty_out(vty, "hlr%s", VTY_NEWLINE);
+
+	if (g_hlr->reject_cause != GMM_CAUSE_IMSI_UNKNOWN)
+		vty_out(vty, " reject-cause not-found %s%s",
+			get_value_string_or_null(gsm48_gmm_cause_vty_names,
+						 (uint32_t) g_hlr->reject_cause), VTY_NEWLINE);
+	if (g_hlr->no_proxy_reject_cause != GMM_CAUSE_IMSI_UNKNOWN)
+		vty_out(vty, " reject-cause no-proxy %s%s",
+			get_value_string_or_null(gsm48_gmm_cause_vty_names,
+						 (uint32_t) g_hlr->no_proxy_reject_cause), VTY_NEWLINE);
 	if (g_hlr->store_imei)
 		vty_out(vty, " store-imei%s", VTY_NEWLINE);
 	if (g_hlr->db_file_path && strcmp(g_hlr->db_file_path, HLR_DEFAULT_DB_FILE_PATH))
@@ -358,6 +400,21 @@ DEFUN(cfg_ncss_guard_timeout, cfg_ncss_guard_timeout_cmd,
 	return CMD_SUCCESS;
 }
 
+
+DEFUN(cfg_reject_cause, cfg_reject_cause_cmd,
+      "reject-cause TYPE CAUSE", "") /* Dynamically Generated */
+{
+	int cause_code = get_string_value(gsm48_gmm_cause_vty_names, argv[1]);
+	OSMO_ASSERT(cause_code >= 0);
+
+	if (strcmp(argv[0], "not-found") == 0)
+		g_hlr->reject_cause = (enum gsm48_gmm_cause) cause_code;
+	if (strcmp(argv[0], "no-proxy") == 0)
+		g_hlr->no_proxy_reject_cause = (enum gsm48_gmm_cause) cause_code;
+
+	return CMD_SUCCESS;
+}
+
 DEFUN(cfg_store_imei, cfg_store_imei_cmd,
 	"store-imei",
 	"Save the IMEI in the database when receiving Check IMEI requests. Note that an MSC does not necessarily send"
@@ -450,8 +507,22 @@ int hlr_vty_is_config_node(struct vty *vty, int node)
 	}
 }
 
-void hlr_vty_init(void)
+void hlr_vty_init(void *hlr_ctx)
 {
+	cfg_reject_cause_cmd.string =
+		vty_cmd_string_from_valstr(hlr_ctx,
+					   gsm48_gmm_cause_vty_names,
+					   "reject-cause (not-found|no-proxy) (", "|", ")",
+					   VTY_DO_LOWER);
+
+	cfg_reject_cause_cmd.doc =
+		vty_cmd_string_from_valstr(hlr_ctx,
+					   gsm48_gmm_cause_vty_descs,
+					   "GSUP/GMM cause to be sent\n"
+					   "in the case the IMSI could not be found in the database\n"
+					   "in the case no remote HLR reponded to mslookup GSUP request\n",
+					   "\n", "", 0);
+
 	logging_vty_add_cmds();
 	osmo_talloc_vty_add_cmds();
 	osmo_stats_vty_add_cmds();
@@ -478,6 +549,7 @@ void hlr_vty_init(void)
 	install_element(HLR_NODE, &cfg_ussd_defaultroute_cmd);
 	install_element(HLR_NODE, &cfg_ussd_no_defaultroute_cmd);
 	install_element(HLR_NODE, &cfg_ncss_guard_timeout_cmd);
+	install_element(HLR_NODE, &cfg_reject_cause_cmd);
 	install_element(HLR_NODE, &cfg_store_imei_cmd);
 	install_element(HLR_NODE, &cfg_no_store_imei_cmd);
 	install_element(HLR_NODE, &cfg_subscr_create_on_demand_cmd);
diff --git a/src/lu_fsm.c b/src/lu_fsm.c
index 8f02f5a..deb180b 100644
--- a/src/lu_fsm.c
+++ b/src/lu_fsm.c
@@ -136,7 +136,7 @@ static void lu_start(struct osmo_gsup_req *update_location_req)
 	}
 
 	if (db_subscr_get_by_imsi(g_hlr->dbc, update_location_req->gsup.imsi, &lu->subscr) < 0) {
-		lu_failure(lu, GMM_CAUSE_IMSI_UNKNOWN, "Subscriber does not exist");
+		lu_failure(lu, g_hlr->reject_cause, "Subscriber does not exist");
 		return;
 	}
 
diff --git a/src/proxy.c b/src/proxy.c
index 152fce8..e909d5a 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -29,6 +29,7 @@
 #include <osmocom/gsupclient/gsup_client.h>
 #include <osmocom/gsupclient/gsup_req.h>
 
+#include <osmocom/hlr/hlr.h>
 #include <osmocom/hlr/logging.h>
 #include <osmocom/hlr/proxy.h>
 #include <osmocom/hlr/remote_hlr.h>
@@ -80,7 +81,19 @@ static void proxy_deferred_gsup_req_add(struct proxy *proxy, struct osmo_gsup_re
 static void proxy_pending_req_remote_hlr_connect_result(struct osmo_gsup_req *req, struct remote_hlr *remote_hlr)
 {
 	if (!remote_hlr || !remote_hlr_is_up(remote_hlr)) {
-		osmo_gsup_req_respond_err(req, GMM_CAUSE_IMSI_UNKNOWN, "Proxy: Failed to connect to home HLR");
+		/* Do not respond with an error to a CHECK_IMEI_REQUEST as osmo-msc will send a LU Reject Cause #6
+		 * Just respond ACK and deal with the IMSI check that comes next. */
+		if (req->gsup.message_type == OSMO_GSUP_MSGT_CHECK_IMEI_REQUEST) {
+			/* Accept all IMEIs */
+			struct osmo_gsup_message gsup_reply = (struct osmo_gsup_message){
+				.message_type = OSMO_GSUP_MSGT_CHECK_IMEI_RESULT,
+				.imei_result  = OSMO_GSUP_IMEI_RESULT_ACK,
+			};
+			osmo_gsup_req_respond(req, &gsup_reply, false, true);
+			return;
+		}
+		osmo_gsup_req_respond_err(req, g_hlr->no_proxy_reject_cause,
+					  "Proxy: Failed to connect to home HLR");
 		return;
 	}
 
diff --git a/tests/test_nodes.vty b/tests/test_nodes.vty
index 0f02f22..ac5d88d 100644
--- a/tests/test_nodes.vty
+++ b/tests/test_nodes.vty
@@ -47,6 +47,7 @@ OsmoHLR(config-hlr)# ?
   no                           Negate a command or set its defaults
   ussd                         USSD Configuration
   ncss-guard-timeout           Set guard timer for NCSS (call independent SS) session activity
+  reject-cause                 GSUP/GMM cause to be sent
   store-imei                   Save the IMEI in the database when receiving Check IMEI requests. Note that an MSC does not necessarily send Check IMEI requests (for OsmoMSC, you may want to set 'check-imei-rqd 1').
   subscriber-create-on-demand  Make a new record when a subscriber is first seen.
 OsmoHLR(config-hlr)# list
@@ -61,6 +62,7 @@ OsmoHLR(config-hlr)# list
   ussd default-route external EUSE
   no ussd default-route
   ncss-guard-timeout <0-255>
+  reject-cause (not-found|no-proxy) (imsi-unknown|illegal-ms|plmn-not-allowed|la-not-allowed|roaming-not-allowed|no-suitable-cell-in-la|net-fail|congestion|auth-unacceptable|proto-error-unspec)
   store-imei
   no store-imei
   subscriber-create-on-demand (no-msisdn|<3-15>) (none|cs|ps|cs+ps)